Bug fixing

* Added NewPath and NewPathFromSvg methods to Canvas interface
* Removed NewPath function
* Removed Reset methods from Path interface

CHANGELOG.md

@@ -1,3 +1,81 @@
+# v0.18.2
+
+* fixed typo: GetShadowPropertys -> GetShadowProperty
+
+# v0.18.0
+
+* Property name type changed from string to PropertyName. 
+
+* Renamed:
+    Transform interface -> TransformProperty
+    NewTransform function -> NewTransformProperty
+    TransformTag constant -> Transform.
+    "origin-x" property -> "transform-origin-x"
+    "origin-y" property -> "transform-origin-y"
+    "origin-z" property -> "transform-origin-z"
+    GetOrigin function -> GetTransformOrigin.
+    BorderBoxClip constant -> BorderBox
+    PaddingBoxClip constant -> PaddingBox
+    ContentBoxClip constant -> ContentBox.
+    ViewShadow interface -> ShadowProperty
+    NewViewShadow function -> NewShadow
+    NewInsetViewShadow function -> NewInsetShadow
+    NewShadowWithParams function -> NewShadowProperty
+    NewColumnSeparator function -> NewColumnSeparatorProperty
+    ClipShape interface -> ClipShapeProperty
+    InsetClip function -> NewInsetClip
+    CircleClip function -> NewCircleClip
+    EllipseClip function -> NewEllipseClip
+    PolygonClip function -> NewPolygonClip
+    PolygonPointsClip function -> NewPolygonPointsClip
+    ViewFilter interface -> FilterProperty
+    NewViewFilter function -> NewFilterProperty
+    Animation interface -> AnimationProperty
+    AnimationTag constant -> Animation
+    NewAnimation function -> NewAnimationProperty
+
+* Added functions: NewBounds, NewEllipticRadius, NewRadii, NewLinearGradient, NewCircleRadialGradient,
+NewEllipseRadialGradient, GetPushTransform, GetPushDuration, GetPushTiming, IsMoveToFrontAnimation,
+GetBackground, GetMask, GetBackgroundClip,GetBackgroundOrigin, GetMaskClip, GetMaskOrigin, NewColumnSeparator,
+NewClipShapeProperty, NewTransitionAnimation, NewAnimation, IsSummaryMarkerHidden.
+
+* Changed ViewByID functions
+
+* Added SetConicGradientFillStyle and SetConicGradientStrokeStyle methods to Canvas interface.
+
+* Changed Push, Pop, MoveToFront, and MoveToFrontByID methods of StackLayout interface.
+
+* Removed DefaultAnimation, StartToEndAnimation, EndToStartAnimation, TopDownAnimation, and BottomUpAnimation constants.
+
+* Added StackLayout properties: "push-transform", "push-duration", "push-timing", "move-to-front-animation", "push-perspective", 
+"push-rotate-x", "push-rotate-y", "push-rotate-z", "push-rotate", "push-skew-x", "push-skew-y",
+"push-scale-x", "push-scale-y", "push-scale-z", "push-translate-x", "push-translate-y", "push-translate-z".
+
+* Added "show-opacity", "show-transform", "show-duration", and "show-timing" Popup properties.
+
+* Added "mask", "mask-clip", "mask-origin", and "background-origin" properties.
+
+* Added "hide-summary-marker" DetailsView property.
+
+* Added LineJoin type. Type of constants MiterJoin, RoundJoin, and BevelJoin changed to LineJoin. Type of Canvas.SetLineJoin function argument changed to LineJoin.
+
+* Added LineCap type. Type of constants ButtCap, RoundCap, and SquareCap changed to LineCap. Type of Canvas.SetLineCap function argument changed to LineCap.
+
+# v0.17.3
+Added SetParams method to View interface
+
+# v0.17.0
+* Added "mod", "rem", "round", "round-up", "round-down", and "round-to-zero" SizeFunc functions
+* Added ModSize, RemSize, RoundSize, RoundUpSize, RoundDownSize, and RoundToZeroSize functions
+* Added Start, Stop, Pause, and Resume methods to Animation interface
+* Added "transform" property and Transform interface
+* Added OpenRawResource, GetCheckboxChangedListeners functions
+* Added RemoveClientItem method to Session interface
+* Added "item-separators" property to DropDownList and GetDropDownItemSeparators function
+* Added NewPath and NewPathFromSvg methods to Canvas interface
+* Removed NewPath function
+* Removed Reset methods from Path interface
+
 # v0.16.0
 * Can use ListAdapter as "content" property value of ListLayout
 * The IsListItemEnabled method of the ListAdapter interface has been made optional 

README-ru.md

@@ -161,6 +161,12 @@ SizeUnit объявлена как
 | "sub(<arg1>, <arg2>)"        | SubSize(arg0, arg1 any)              | находит разность значений аргументов            |
 | "mul(<arg1>, <arg2>)"        | MulSize(arg0, arg1 any)              | находит результат умножения значений аргументов |
 | "div(<arg1>, <arg2>)"        | DivSize(arg0, arg1 any)              | находит результат деления значений аргументов   |
+| "rem(<arg1>, <arg2>)"        | ModSize(arg0, arg1 any)              | находит остаток деления значений аргументов, результат имеет тотже знак что и делимое   |
+| "mod(<arg1>, <arg2>)"        | ModSize(arg0, arg1 any)              | находит остаток деления значений аргументов, результат имеет тотже знак что и делитель   |
+| "round(<arg1>, <arg2>)"      | RoundSize(arg0, arg1 any)            | округляет первый аргумент до ближайшего целого числа кратного второму аргументу   |
+| "round-up(<arg1>, <arg2>)"   | RoundUpSize(arg0, arg1 any)          | округляет первый аргумент до ближайшего большего целого числа, кратного второму аргументу   |
+| "round-down(<arg1>, <arg2>)" | RoundDownSize(arg0, arg1 any)        | округляет первый аргумент до ближайшего меньшего целого числа кратного второму аргументу   |
+| "round-to-zero(<arg1>, <arg2>)" | RoundToZeroSize(arg0, arg1 any)   | округляет первый аргумент до ближайшего целого числа кратного второму аргументу, которое ближе к нулю по сравнению с первым аргументом   |
 | "clamp(<min>, <val>, <max>)" | ClampSize(min, val, max any)         | ограничивает значение заданным диапазоном       |
 
 Дополнительные пояснения к функции "clamp(<min>, <val>, <max>)": результат вычисляется следующим образом:
@@ -169,6 +175,17 @@ SizeUnit объявлена как
 * if val < min then min;
 * if max < val then max;
 
+Аргументы всех функций могут иметь следующий тип:
+
+* SizeUnit;
+* SizeFunc;
+* string являющееся SizeUnit константой или текстовым представлением SizeUnit или SizeFunc.
+
+Кроме этого второй аргумент функций mul, div, mod, rem и всех round может быть числом 
+(float32, float32, int, int8...int64, uint, uint8...unit64).
+
+Также второй аргумент функций div, mod, rem и всех round не может быть нулевым значением.
+
 ### Color
 
 Тип Color описывает 32-битный цвет в формате ARGB:
@@ -408,7 +425,7 @@ View имеет ряд свойств, таких как высота, шири
 (View реализует данный интерфейс):
 
 	type Properties interface {
-		Get(tag string) any
+		Get(tag PropertyName) any
 		Set(tag string, value any) bool
 		Remove(tag string)
 		Clear()
@@ -1030,7 +1047,7 @@ RadiusProperty, а не структура BoxRadius. Получить стру
 ### Свойство "shadow"
 
 Свойство "shadow" позволяет задать тени для View. Теней может быть несколько. Тень описывается
-с помощью интерфейса ViewShadow расширяющего интерфейс Properties (см. выше). У тени имеются следующие свойства:
+с помощью интерфейса ShadowProperty расширяющего интерфейс Properties (см. выше). У тени имеются следующие свойства:
 
 | Свойство        | Константа     | Тип      | Описание                                                      |
 |-----------------|---------------|----------|---------------------------------------------------------------|
@@ -1041,13 +1058,13 @@ RadiusProperty, а не структура BoxRadius. Получить стру
 | "blur"          | BlurRadius    | float    | Радиус размытия тени. Значение должно быть >= 0               |
 | "spread-radius" | SpreadRadius  | float    | Увеличение тени. Значение > 0 увеличивает тень, < 0 уменьшает |
 
-Для создания ViewShadow используются три функции:
+Для создания ShadowProperty используются три функции:
 
-	func NewViewShadow(offsetX, offsetY, blurRadius, spread-radius SizeUnit, color Color) ViewShadow
-	func NewInsetViewShadow(offsetX, offsetY, blurRadius, spread-radius SizeUnit, color Color) ViewShadow
-	func NewShadowWithParams(params Params) ViewShadow
+	func NewShadowProperty(offsetX, offsetY, blurRadius, spread-radius SizeUnit, color Color) ShadowProperty
+	func NewInsetShadowProperty(offsetX, offsetY, blurRadius, spread-radius SizeUnit, color Color) ShadowProperty
+	func NewShadowWithParams(params Params) ShadowProperty
 
-Функция NewViewShadow создает внешнюю тень (Inset == false), NewInsetViewShadow - внутреннюю
+Функция NewShadowProperty создает внешнюю тень (Inset == false), NewInsetShadowProperty - внутреннюю
 (Inset == true).
 Функция NewShadowWithParams используется когда в качестве параметров необходимо использовать
 константы. Например:
@@ -1058,10 +1075,10 @@ RadiusProperty, а не структура BoxRadius. Получить стру
 		rui.Dilation : 16.0,
 	})
 
-В качестве значения свойству "shadow" может быть присвоено ViewShadow, массив ViewShadow,
-текстовое представление ViewShadow.
+В качестве значения свойству "shadow" может быть присвоено ShadowProperty, массив ShadowProperty,
+текстовое представление ShadowProperty.
 
-Текстовое представление ViewShadow имеет следующий формат:
+Текстовое представление ShadowProperty имеет следующий формат:
 
 	_{ color = <цвет> [, x-offset = <смещение>] [, y-offset = <смещение>] [, blur = <радиус>]
 		[, spread-radius = <увеличение>] [, inset = <тип>] }
@@ -1069,7 +1086,7 @@ RadiusProperty, а не структура BoxRadius. Получить стру
 
 Получить значение данного свойства можно с помощью функции
 
-	func GetViewShadows(view View, subviewID ...string) []ViewShadow
+	func GetShadowPropertys(view View, subviewID ...string) []ShadowProperty
 
 Если тень не задана, то данная функция вернет пустой массив
 
@@ -1305,14 +1322,14 @@ AngleUnit или string (угловая константа или текстов
 
 ### Свойство "clip"
 
-Свойство "clip" (константа Clip) типа ClipShape задает задает область образки.
+Свойство "clip" (константа Clip) типа ClipShapeProperty задает задает область образки.
 Есть 4 типа областей обрезки
 
 #### inset
 
 Прямоугольная область обрезки. Создается с помощью функции:
 
-	func InsetClip(top, right, bottom, left SizeUnit, radius RadiusProperty) ClipShape
+	func NewInsetClip(top, right, bottom, left SizeUnit, radius RadiusProperty) ClipShapeProperty
 
 где top, right, bottom, left это расстояние от соответственно верхней, правой, нижней и левой границы
 View до одноименной границы обрезки; radius - задает радиусы скругления углов области обрезки
@@ -1329,7 +1346,7 @@ radius необходимо передать nil
 
 Круглая область обрезки. Создается с помощью функции:
 
-	func CircleClip(x, y, radius SizeUnit) ClipShape
+	func NewCircleClip(x, y, radius SizeUnit) ClipShapeProperty
 
 где x, y - координаты центра окружности; radius - радиус
 
@@ -1341,7 +1358,7 @@ radius необходимо передать nil
 
 Эллиптическая область обрезки. Создается с помощью функции:
 
-	func EllipseClip(x, y, rx, ry SizeUnit) ClipShape
+	func NewEllipseClip(x, y, rx, ry SizeUnit) ClipShapeProperty
 
 где x, y - координаты центра эллипса; rх - радиус эллипса по оси X; ry - радиус эллипса по оси Y.
 
@@ -1353,8 +1370,8 @@ radius необходимо передать nil
 
 Многоугольная область обрезки. Создается с помощью функций:
 
-	func PolygonClip(points []any) ClipShape
-	func PolygonPointsClip(points []SizeUnit) ClipShape
+	func NewPolygonClip(points []any) ClipShapeProperty
+	func NewPolygonPointsClip(points []SizeUnit) ClipShapeProperty
 
 в качестве аргумента передается массив угловых точек многоугольника в следующем порядке: x1, y1, x2, y2, …
 В качестве элементов аргумента функции PolygonClip могут быть или текстовые константы, или
@@ -1418,10 +1435,10 @@ radius необходимо передать nil
 Свойство "filter" (константа Filter) применяет ко View такие графические эффекты, как размытие, смещение цвета, изменение яркости/контрастности и т.п.
 Свойства "backdrop-filter" (константа BackdropFilter) применяет такие же эффекты но к содержимому располагающемся ниже View.
 
-В качестве значения свойств "filter" и "backdrop-filter" используется только интерфейс ViewFilter. ViewFilter создается с помощью
+В качестве значения свойств "filter" и "backdrop-filter" используется только интерфейс FilterProperty. FilterProperty создается с помощью
 функции
 
-	func NewViewFilter(params Params) ViewFilter
+	func NewFilterProperty(params Params) FilterProperty
 
 В аргументе перечисляются применяемые эффекты. Возможны следующие эффекты:
 
@@ -1430,7 +1447,7 @@ radius необходимо передать nil
 | "blur"        | Blur       | float64  0…10000px | Размытие по Гауссу               |
 | "brightness"  | Brightness | float64  0…10000%  | Изменение яркости                |
 | "contrast"    | Contrast   | float64  0…10000%  | Изменение контрастности          |
-| "drop-shadow" | DropShadow | []ViewShadow       | Добавление тени                  |
+| "drop-shadow" | DropShadow | []ShadowProperty       | Добавление тени                  |
 | "grayscale"   | Grayscale  | float64  0…100%    | Преобразование к оттенкам серого |
 | "hue-rotate"  | HueRotate  | AngleUnit          | Вращение оттенка                 |
 | "invert"      | Invert     | float64  0…100%    | Инвертирование цветов            |
@@ -1440,8 +1457,8 @@ radius необходимо передать nil
 
 Получить значение текущего фильтра можно с помощью функций
 
-	func GetFilter(view View, subviewID ...string) ViewFilter
-	func GetBackdropFilter(view View, subviewID ...string) ViewFilter
+	func GetFilter(view View, subviewID ...string) FilterProperty
+	func GetBackdropFilter(view View, subviewID ...string) FilterProperty
 
 ### Свойство "semantics"
 
@@ -1687,14 +1704,14 @@ radius необходимо передать nil
 #### Свойство "text-shadow"
 
 Свойство "text-shadow" позволяет задать тени для текста. Теней может быть несколько. Тень описывается
-с помощью интерфейса ViewShadow (см. выше, раздел "Свойство 'shadow'"). Для тени текста используются только
+с помощью интерфейса ShadowProperty (см. выше, раздел "Свойство 'shadow'"). Для тени текста используются только
 Свойства "color", "x-offset", "y-offset" и "blur". Свойства "inset" и "spread-radius" игнорируются (т.е. их
 задание не является ошибкой, просто никакого влияния на тень текста они не имеют).
 
-Для создания ViewShadow для тени текста используются функции:
+Для создания ShadowProperty для тени текста используются функции:
 
-	func NewTextShadow(offsetX, offsetY, blurRadius SizeUnit, color Color) ViewShadow
-	func NewShadowWithParams(params Params) ViewShadow
+	func NewTextShadow(offsetX, offsetY, blurRadius SizeUnit, color Color) ShadowProperty
+	func NewShadowWithParams(params Params) ShadowProperty
 
 Функция NewShadowWithParams используется когда в качестве параметров необходимо использовать
 константы. Например:
@@ -1704,12 +1721,12 @@ radius необходимо передать nil
 		rui.BlurRadius : 8.0,
 	})
 
-В качестве значения свойству "text-shadow" может быть присвоено ViewShadow, массив ViewShadow,
-текстовое представление ViewShadow (см. выше, раздел "Свойство 'shadow'").
+В качестве значения свойству "text-shadow" может быть присвоено ShadowProperty, массив ShadowProperty,
+текстовое представление ShadowProperty (см. выше, раздел "Свойство 'shadow'").
 
 Получить значение данного свойства можно с помощью функции
 
-	func GetTextShadows(view View, subviewID ...string) []ViewShadow
+	func GetTextShadows(view View, subviewID ...string) []ShadowProperty
 
 Если тень не задана, то данная функция вернет пустой массив
 
@@ -2963,13 +2980,14 @@ DetailsView переключается между состояниями по к
 "expanded" (константа Expanded). Соответственно значение "true" показывает дочерние
 View, "false" - скрывает.
 
-Получить значение свойства "expanded" можно с помощью функции
+По умолчанию в начале элемента "summary" отображается маркер ▶︎/▼. Его можно спрятать.
+Для этого используется свойство "hide-summary-marker" (константа DetailsView) типа bool.
 
-	func IsDetailsExpanded(view View, subviewID ...string) bool
-
-а значение свойства "summary" можно получить с помощью функции
+Получить значение свойств "summary", "expanded" и "hide-summary-marker" можно с помощью функций
 
 	func GetDetailsSummary(view View, subviewID ...string) View
+	func IsDetailsExpanded(view View, subviewID ...string) bool
+	func IsSummaryMarkerHidden(view View, subviewID ...string) bool
 
 ## Resizable
 
@@ -3626,6 +3644,13 @@ float32, float64, int, int8…int64, uint, uint8…uint64.
 
 	func GetDropDownDisabledItems(view View, subviewID ...string) []int
 
+Между пунктами списка можно добавлять разделителями. Для этого используется свойство "item-separators" (константа ItemSeparators).
+Данному свойству присваивается массив индексов пунктов после которых необходимо добавить разделители. 
+Свойству "item-separators" могут присваиваться теже типы данных что и свойству "disabled-items".
+Прочитать значение свойства "item-separators" можно с помощью функции
+
+	func GetDropDownItemSeparators(view View, subviewID ...string) []int
+
 Выбранное значение определяется int свойством "current" (константа Current). Значение по умолчанию 0.
 Прочитать значение данного свойства можно с помощью функции
 
@@ -4426,7 +4451,17 @@ rotation - угол поворота эллипса относительно ц
 
 #### Path
 
-Интерфейс Path позволяет описать сложную фигуру. Создается Path с помощью функции NewPath().
+Интерфейс Path позволяет описать сложную фигуру. Для создания объекта Path используются два метода Canvas:
+
+	NewPath() Path
+	NewPathFromSvg(data string) Path
+
+Метод NewPath() создает пустую фигуру. Далее вы должны описать фигуру используя методы интерфейса Path
+
+Метод NewPathFromSvg(data string) Path создает фигуру описанную в параметре data. 
+Параметр data является описанием фигуры в формате елемента <path> svg изображения. Например
+
+	path := canvas.NewPathFromSvg("M 30,0 C 30,0 27,8.6486 17,21.622 7,34.595 0,40 0,40 0,40 6,44.3243 17,58.378 28,72.432 30,80 30,80 30,80 37.8387,65.074 43,58.378 53,45.405 60,40 60,40 60,40 53,34.5946 43,21.622 33,8.649 30,0 30,0 Z")
 
 После создания вы должны описать фигуру. Для этого могут использоваться следующие функции интерфейса:
 
@@ -5004,14 +5039,14 @@ onNo или onCancel (если она не nil).
 * Анимированное изменения значения свойства (далее "анимация перехода") 
 * Сценарий анимированного изменения одного или нескольких свойств (далее просто "сценарий анимации")
 
-### Интерфейс Animation
+### Интерфейс AnimationProperty
 
-Для задания параметров анимации используется интерфейс Animation. Он расширяет интерфейс Properties.
+Для задания параметров анимации используется интерфейс AnimationProperty. Он расширяет интерфейс Properties.
 Интерфейс создается с помощью функции:
 
-	func NewAnimation(params Params) Animation
+	func NewAnimationProperty(params Params) AnimationProperty
 
-Часть свойств интерфейса Animation используется в обоих типах анимации, остальные используются 
+Часть свойств интерфейса AnimationProperty используется в обоих типах анимации, остальные используются 
 только в сценариях анимации.
 
 Общими свойствами являются
@@ -5048,13 +5083,13 @@ onNo или onCancel (если она не nil).
 
 Например
 
-	animation := rui.NewAnimation(rui.Params{
+	animation := rui.NewAnimationProperty(rui.Params{
 		rui.TimingFunction: rui.StepsTiming(10),
 	})
 
 эквивалентно 
 
-	animation := rui.NewAnimation(rui.Params{
+	animation := rui.NewAnimationProperty(rui.Params{
 		rui.TimingFunction: "steps(10)",
 	})
 	
@@ -5078,31 +5113,31 @@ x1 и x2 должны быть в диапазоне [0, 1]. Вы можете
 Однократная анимация запускается с помощью функции SetAnimated интерфейса View. Данная функция имеет следующее
 описание:
 
-	SetAnimated(tag string, value any, animation Animation) bool
+	SetAnimated(tag string, value any, animation AnimationProperty) bool
 
 Она присваивает свойству новое значение, при этом изменение происходит с использованием заданной анимации.
 Например,
 
-	view.SetAnimated(rui.Width, rui.Px(400), rui.NewAnimation(rui.Params{
+	view.SetAnimated(rui.Width, rui.Px(400), rui.NewAnimationProperty(rui.Params{
 		rui.Duration:       0.75,
 		rui.TimingFunction: rui.EaseOutTiming,
 	}))
 
 Есть также глобальная функция для анимированного однократного изменения значения свойства дочернего View
 
-	func SetAnimated(rootView View, viewID, tag string, value any, animation Animation) bool
+	func SetAnimated(rootView View, viewID, tag string, value any, animation AnimationProperty) bool
 
 Постоянная анимация запускается каждый раз когда изменяется значение свойства. Для задания постоянной 
 анимации перехода используется свойство "transition" (константа Transition). В качества значения данному 
-Свойству присваивается rui.Params, где в качестве ключа должно быть имя свойства, а значение - интерфейс Animation.
+Свойству присваивается rui.Params, где в качестве ключа должно быть имя свойства, а значение - интерфейс AnimationProperty.
 Например,
 
 	view.Set(rui.Transition, rui.Params{
-		rui.Height: rui.NewAnimation(rui.Params{
+		rui.Height: rui.NewAnimationProperty(rui.Params{
 			rui.Duration:       0.75,
 			rui.TimingFunction: rui.EaseOutTiming,
 		},
-		rui.BackgroundColor: rui.NewAnimation(rui.Params{
+		rui.BackgroundColor: rui.NewAnimationProperty(rui.Params{
 			rui.Duration:       1.5,
 			rui.Delay:          0.5,
 			rui.TimingFunction: rui.Linear,
@@ -5117,7 +5152,7 @@ x1 и x2 должны быть в диапазоне [0, 1]. Вы можете
 
 Добавлять новые анимации перехода рекомендуется с помощью функции 
 
-	func AddTransition(view View, subviewID, tag string, animation Animation) bool
+	func AddTransition(view View, subviewID, tag string, animation AnimationProperty) bool
 
 Вызов данной функции эквивалентен следующему коду
 
@@ -5158,7 +5193,7 @@ x1 и x2 должны быть в диапазоне [0, 1]. Вы можете
 ### Сценарий анимации
 
 Сценарий анимации описывает более сложную анимацию, по сравнению с анимацией перехода. Для этого
-в Animation добавляются дополнительные свойства:
+в AnimationProperty добавляются дополнительные свойства:
 
 #### Свойство "property"
 
@@ -5222,11 +5257,11 @@ KeyFrames - промежуточные значения свойства (клю
 
 #### Запуск анимации
 
-Для запуска сценария анимации необходимо созданный Animation интерфейс присвоить свойству "animation"
-(константа AnimationTag). Если View уже отображается на экране, то анимация запускается сразу (с учетом
+Для запуска сценария анимации необходимо созданный AnimationProperty интерфейс присвоить свойству "animation"
+(константа Animation). Если View уже отображается на экране, то анимация запускается сразу (с учетом
 заданной задержки), в противоположном случае анимация запускается как только View отобразится на экране.
 
-Свойству "animation" можно присваивать Animation и []Animation, т.е. можно запускать несколько анимаций 
+Свойству "animation" можно присваивать AnimationProperty и []AnimationProperty, т.е. можно запускать несколько анимаций 
 одновременно для одного View
 
 Пример,
@@ -5239,12 +5274,12 @@ KeyFrames - промежуточные значения свойства (клю
 			90: rui.Px(220),
 		}
 	}
-	animation := rui.NewAnimation(rui.Params{
+	animation := rui.NewAnimationProperty(rui.Params{
 		rui.PropertyTag:    []rui.AnimatedProperty{prop},
 		rui.Duration:       2,
 		rui.TimingFunction: LinearTiming,
 	})
-	rui.Set(view, "subview", rui.AnimationTag, animation)
+	rui.Set(view, "subview", rui.Animation, animation)
 
 #### Свойство "animation-paused"
 

README.md

@@ -164,6 +164,12 @@ In addition to "min", there are the following functions
 | "sub(<arg1>, <arg2>)"        | SubSize(arg0, arg1 any)              | calculates the subtraction of argument values            |
 | "mul(<arg1>, <arg2>)"        | MulSize(arg0, arg1 any)              | calculates the result of multiplying the argument values |
 | "div(<arg1>, <arg2>)"        | DivSize(arg0, arg1 any)              | calculates the result of dividing the argument values    |
+| "rem(<arg1>, <arg2>)"        | ModSize(arg0, arg1 any)              | calculates the remainder of a division operation with the same sign as the dividend   |
+| "mod(<arg1>, <arg2>)"        | ModSize(arg0, arg1 any)              | calculates the remainder of a division operation with the same sign as the divisor   |
+| "round(<arg1>, <arg2>)"      | RoundSize(arg0, arg1 any)            | rounds the first argument to the nearest integer multiple of the second argument, which may be either above or below the value.  |
+| "round-up(<arg1>, <arg2>)"   | RoundUpSize(arg0, arg1 any)          | rounds the first argument up to the nearest integer multiple of the second argument (if the value is negative, it will become "more positive") |
+| "round-down(<arg1>, <arg2>)" | RoundDownSize(arg0, arg1 any)        | rounds the first argument down to the nearest integer multiple of the second argument (if the value is negative, it will become "more negative") |
+| "round-to-zero(<arg1>, <arg2>)" | RoundToZeroSize(arg0, arg1 any)   | rounds the first argument to the nearest integer multiple of the second argument closer to/towards zero (a positive number will decrease, while a negative value will become "less negative") |
 | "clamp(<min>, <val>, <max>)" | ClampSize(min, val, max any)         | limits value to specified range                          |
 
 Additional explanations for the function "clamp(<min>, <val>, <max>)": the result is calculated as follows:
@@ -172,6 +178,17 @@ Additional explanations for the function "clamp(<min>, <val>, <max>)": the resul
 * if val < min then min;
 * if max < val then max;
 
+The arguments of all functions can be of the following type:
+
+* SizeUnit;
+* SizeFunc;
+* string being a SizeUnit constant or a text representation of SizeUnit or SizeFunc.
+
+In addition, the second argument of the functions mul, div, mod, rem, and all round can be a number
+(float32, float32, int, int8...int64, uint, uint8...unit64).
+
+Also, the second argument of the div, mod, rem, and all round functions cannot be a zero value.
+
 ### Color
 
 The Color type describes a 32-bit ARGB color:
@@ -412,7 +429,7 @@ View has a number of properties like height, width, color, text parameters, etc.
 The Properties interface is used to read and write the property value (View implements this interface):
 
 	type Properties interface {
-		Get(tag string) any
+		Get(tag PropertyName) any
 		Set(tag string, value any) bool
 		Remove(tag string)
 		Clear()
@@ -1007,7 +1024,7 @@ equivalent to
 ### "shadow" property
 
 The "shadow" property allows you to set shadows for the View. There may be several shadows. 
-The shadow is described using the ViewShadow interface extending the Properties interface (see above). 
+The shadow is described using the ShadowProperty interface extending the Properties interface (see above). 
 The shadow has the following properties:
 
 | Property        | Constant      | Type     | Description                                                           |
@@ -1019,14 +1036,14 @@ The shadow has the following properties:
 | "blur"          | BlurRadius    | float    | Shadow blur radius. The value must be >= 0                            |
 | "spread-radius" | SpreadRadius  | float    | Increase the shadow. Value > 0 increases shadow, < 0 decreases shadow |
 
-Three functions are used to create a ViewShadow:
+Three functions are used to create a ShadowProperty:
 
-	func NewViewShadow(offsetX, offsetY, blurRadius, spread-radius SizeUnit, color Color) ViewShadow
-	func NewInsetViewShadow(offsetX, offsetY, blurRadius, spread-radius SizeUnit, color Color) ViewShadow
-	func NewShadowWithParams(params Params) ViewShadow
+	func NewShadowProperty(offsetX, offsetY, blurRadius, spread-radius SizeUnit, color Color) ShadowProperty
+	func NewInsetShadowProperty(offsetX, offsetY, blurRadius, spread-radius SizeUnit, color Color) ShadowProperty
+	func NewShadowWithParams(params Params) ShadowProperty
 
-The NewViewShadow function creates an outer shadow (Inset == false), 
-NewInsetViewShadow - an inner one (Inset == true).
+The NewShadowProperty function creates an outer shadow (Inset == false), 
+NewInsetShadowProperty - an inner one (Inset == true).
 The NewShadowWithParams function is used when constants must be used as parameters. 
 For example:
 
@@ -1036,16 +1053,16 @@ For example:
 		rui.Dilation  : 16.0,
 	})
 
-ViewShadow, ViewShadow array, and ViewShadow textual representation can be assigned as a value to the "shadow" property.
+ShadowProperty, ShadowProperty array, and ShadowProperty textual representation can be assigned as a value to the "shadow" property.
 
-The ViewShadow text representation has the following format:
+The ShadowProperty text representation has the following format:
 
 	_{ color = <color> [, x-offset = <offset>] [, y-offset = <offset>] [, blur = <radius>]
 		[, spread-radius = <increase>] [, inset = <type>] }
 
 You can get the value of "shadow" property using the function
 
-	func GetViewShadows(view View, subviewID ...string) []ViewShadow
+	func GetShadowPropertys(view View, subviewID ...string) []ShadowProperty
 
 If no shadow is specified, then this function will return an empty array
 
@@ -1202,6 +1219,10 @@ The textual representation of a conic gradient looks like this:
 
 #### Image
 
+The background image is created using the function
+
+	func NewBackgroundImage(params Params) BackgroundElement
+
 The image has the following parameters:
 
 * Source ("src") - Specifies the URL of the image
@@ -1280,14 +1301,14 @@ You can get the value of this property using the function
 
 ### "clip" property
 
-The "clip" property (Clip constant) of the ClipShape type specifies the crop area.
+The "clip" property (Clip constant) of the ClipShapeProperty type specifies the crop area.
 There are 4 types of crop areas
 
 #### inset
 
 Rectangular cropping area. Created with the function:
 
-	func InsetClip(top, right, bottom, left SizeUnit, radius RadiusProperty) ClipShape
+	func NewInsetClip(top, right, bottom, left SizeUnit, radius RadiusProperty) ClipShapeProperty
 
 where top, right, bottom, left are the distance from respectively the top, right, bottom and left borders of the View 
 to the cropping border of the same name; radius - sets the radii of the corners of the cropping area 
@@ -1303,7 +1324,7 @@ The textual description of the rectangular cropping area is in the following for
 
 Round cropping area. Created with the function:
 
-	func CircleClip(x, y, radius SizeUnit) ClipShape
+	func NewCircleClip(x, y, radius SizeUnit) ClipShapeProperty
 
 where x, y - coordinates of the center of the circle; radius - radius
 
@@ -1315,7 +1336,7 @@ The textual description of the circular cropping area is in the following format
 
 Elliptical cropping area. Created with the function:
 
-	func EllipseClip(x, y, rx, ry SizeUnit) ClipShape
+	func NewEllipseClip(x, y, rx, ry SizeUnit) ClipShapeProperty
 
 where x, y - coordinates of the center of the ellipse; rх - radius of the ellipse along the X axis; ry is the radius of the ellipse along the Y axis.
 
@@ -1327,8 +1348,8 @@ The textual description of the elliptical clipping region is in the following fo
 
 Polygonal cropping area. Created using functions:
 
-	func PolygonClip(points []any) ClipShape
-	func PolygonPointsClip(points []SizeUnit) ClipShape
+	func NewPolygonClip(points []any) ClipShapeProperty
+	func NewPolygonPointsClip(points []SizeUnit) ClipShapeProperty
 
 an array of corner points of the polygon is passed as an argument in the following order: x1, y1, x2, y2, …
 The elements of the argument to the PolygonClip function can be either text constants, 
@@ -1392,10 +1413,10 @@ You can get the value of this property using the function
 The "filter" property (Filter constant) applies graphical effects to the View, such as blurring, color shifting, changing brightness/contrast, etc.
 The "backdrop-filter" property (BackdropFilter constant) applies the same effects but to the area behind a View.
 
-Only the ViewFilter interface is used as the value of the "filter" properties. 
-ViewFilter is created using the function
+Only the FilterProperty interface is used as the value of the "filter" properties. 
+FilterProperty is created using the function
 
-	func NewViewFilter(params Params) ViewFilter
+	func NewFilterProperty(params Params) FilterProperty
 
 The argument lists the effects to apply. The following effects are possible:
 
@@ -1404,7 +1425,7 @@ The argument lists the effects to apply. The following effects are possible:
 | "blur"        | Blur       | float64  0…10000px | Gaussian blur           |
 | "brightness"  | Brightness | float64  0…10000%  | Brightness change       |
 | "contrast"    | Contrast   | float64  0…10000%  | Contrast change         |
-| "drop-shadow" | DropShadow | []ViewShadow       | Adding shadow           |
+| "drop-shadow" | DropShadow | []ShadowProperty       | Adding shadow           |
 | "grayscale"   | Grayscale  | float64  0…100%    | Converting to grayscale |
 | "hue-rotate"  | HueRotate  | AngleUnit          | Hue rotation            |
 | "invert"      | Invert     | float64  0…100%    | Invert colors           |
@@ -1421,8 +1442,8 @@ Example
 
 You can get the value of the current filter using functions
 
-	func GetFilter(view View, subviewID ...string) ViewFilter
-	func GetBackdropFilter(view View, subviewID ...string) ViewFilter
+	func GetFilter(view View, subviewID ...string) FilterProperty
+	func GetBackdropFilter(view View, subviewID ...string) FilterProperty
 
 ### "semantics" property
 
@@ -1665,14 +1686,14 @@ You can get the value of this property using the function
 #### "text-shadow" property
 
 The "text-shadow" property allows you to set shadows for the text. There may be several shadows. 
-The shadow is described using the ViewShadow interface (see above, section "The 'shadow' property"). 
+The shadow is described using the ShadowProperty interface (see above, section "The 'shadow' property"). 
 For text shadow, only the "color", "x-offset", "y-offset" and "blur" properties are used. 
 The "inset" and "spread-radius" properties are ignored (i.e. setting them is not an error, they just have no effect on the text shadow).
 
-To create a ViewShadow for the text shadow, the following functions are used:
+To create a ShadowProperty for the text shadow, the following functions are used:
 
-	func NewTextShadow(offsetX, offsetY, blurRadius SizeUnit, color Color) ViewShadow
-	func NewShadowWithParams(params Params) ViewShadow
+	func NewTextShadow(offsetX, offsetY, blurRadius SizeUnit, color Color) ShadowProperty
+	func NewShadowWithParams(params Params) ShadowProperty
 
 The NewShadowWithParams function is used when constants must be used as parameters. For example:
 
@@ -1681,11 +1702,11 @@ The NewShadowWithParams function is used when constants must be used as paramete
 		rui.BlurRadius: 8.0,
 	})
 
-ViewShadow, ViewShadow array, ViewShadow textual representation can be assigned as a value to the "text-shadow" property (see above, section "The 'shadow' property").
+ShadowProperty, ShadowProperty array, ShadowProperty textual representation can be assigned as a value to the "text-shadow" property (see above, section "The 'shadow' property").
 
 You can get the value of this property using the function
 
-	func GetTextShadows(view View, subviewID ...string) []ViewShadow
+	func GetTextShadows(view View, subviewID ...string) []ShadowProperty
 
 If no shadow is specified, then this function will return an empty array
 
@@ -2942,13 +2963,14 @@ DetailsView switches between states by clicking on "summary" view.
 For forced switching of the DetailsView states, the bool property "expanded" (Expanded constant) is used. 
 Accordingly, the value "true" shows child Views, "false" - hides.
 
-You can get the value of the "expanded" property using the function
+By default, a ▶︎/▼ marker is displayed at the beginning of the "summary" element. It can be hidden.
+For this, the "hide-summary-marker" bool property (DetailsView constant) is used.
 
-	func IsDetailsExpanded(view View, subviewID ...string) bool
-
-and the value of the "summary" property can be obtained using the function
+The value of the "summary", "expanded" and "hide-summary-marker" properties can be obtained using the functions
 
 	func GetDetailsSummary(view View, subviewID ...string) View
+	func IsDetailsExpanded(view View, subviewID ...string) bool
+	func IsSummaryMarkerHidden(view View, subviewID ...string) bool
 
 ## Resizable
 
@@ -3599,6 +3621,13 @@ You can read the value of the "disabled-items" property using the function
 
 	func GetDropDownDisabledItems(view View, subviewID ...string) []int
 
+You can add separators between list items. To do this, use the "item-separators" property (the ItemSeparators constant).
+This property is assigned an array of item indices after which separators must be added.
+The "item-separators" property can be assigned the same data types as the "disabled-items" property.
+You can read the value of the "item-separators" property using the function
+
+	func GetDropDownItemSeparators(view View, subviewID ...string) []int
+
 The selected value is determined by the int property "current" (Current constant). The default is 0.
 You can read the value of this property using the function
 
@@ -4390,7 +4419,17 @@ rotation - the angle of rotation of the ellipse relative to the center in radian
 
 #### Path
 
-The Path interface allows you to describe a complex shape. Path is created using the NewPath () function.
+The Path interface allows you to describe a complex shape. Two Canvas methods are used to create a Path object:
+
+	NewPath() Path
+	NewPathFromSvg(data string) Path
+
+The NewPath() method creates an empty shape. Next, you must describe the shape using the methods of the Path interface
+
+The NewPathFromSvg(data string) Path method creates the shape described in the data parameter.
+The data parameter is a description of the shape in the format of a <path> svg image element. For example
+
+	path := canvas.NewPathFromSvg("M 30,0 C 30,0 27,8.6486 17,21.622 7,34.595 0,40 0,40 0,40 6,44.3243 17,58.378 28,72.432 30,80 30,80 30,80 37.8387,65.074 43,58.378 53,45.405 60,40 60,40 60,40 53,34.5946 43,21.622 33,8.649 30,0 30,0 Z")
 
 Once created, you must describe the shape. For this, the following interface functions can be used:
 
@@ -4971,14 +5010,14 @@ The library supports two types of animation:
 * Animated property value changes (hereinafter "transition animation")
 * Script animated change of one or more properties (hereinafter simply "animation script")
 
-### Animation interface
+### AnimationProperty interface
 
-The Animation interface is used to set animation parameters. It extends the Properties interface.
+The AnimationProperty interface is used to set animation parameters. It extends the Properties interface.
 The interface is created using the function:
 
-	func NewAnimation(params Params) Animation
+	func NewAnimationProperty(params Params) AnimationProperty
 
-Some of the properties of the Animation interface are used in both types of animation, the rest are used only 
+Some of the properties of the AnimationProperty interface are used in both types of animation, the rest are used only 
 in animation scripts.
 
 Common properties are
@@ -5015,13 +5054,13 @@ You can specify this function either as text or using the function:
 
 For example
 
-	animation := rui.NewAnimation(rui.Params{
+	animation := rui.NewAnimationProperty(rui.Params{
 		rui.TimingFunction: rui.StepsTiming(10),
 	})
 
 equivalent to 
 
-	animation := rui.NewAnimation(rui.Params{
+	animation := rui.NewAnimationProperty(rui.Params{
 		rui.TimingFunction: "steps(10)",
 	})
 	
@@ -5044,32 +5083,32 @@ There are two types of transition animations:
 A one-time animation is triggered using the SetAnimated function of the View interface. 
 This function has the following description:
 
-	SetAnimated(tag string, value any, animation Animation) bool
+	SetAnimated(tag string, value any, animation AnimationProperty) bool
 
 It assigns a new value to the property, and the change occurs using the specified animation.
 For example,
 
-	view.SetAnimated(rui.Width, rui.Px(400), rui.NewAnimation(rui.Params{
+	view.SetAnimated(rui.Width, rui.Px(400), rui.NewAnimationProperty(rui.Params{
 		rui.Duration:       0.75,
 		rui.TimingFunction: rui.EaseOutTiming,
 	}))
 
 There is also a global function for animated one-time change of the property value of the child View
 
-	func SetAnimated(rootView View, viewID, tag string, value any, animation Animation) bool
+	func SetAnimated(rootView View, viewID, tag string, value any, animation AnimationProperty) bool
 
 A persistent animation runs every time the property value changes. 
 To set the constant animation of the transition, use the "transition" property (the Transition constant). 
 As a value, this property is assigned rui.Params, where the property name should be the key, 
-and the value should be the Animation interface.
+and the value should be the AnimationProperty interface.
 For example,
 
 	view.Set(rui.Transition, rui.Params{
-		rui.Height: rui.NewAnimation(rui.Params{
+		rui.Height: rui.NewAnimationProperty(rui.Params{
 			rui.Duration:       0.75,
 			rui.TimingFunction: rui.EaseOutTiming,
 		},
-		rui.BackgroundColor: rui.NewAnimation(rui.Params{
+		rui.BackgroundColor: rui.NewAnimationProperty(rui.Params{
 			rui.Duration:       1.5,
 			rui.Delay:          0.5,
 			rui.TimingFunction: rui.Linear,
@@ -5084,7 +5123,7 @@ To get the current list of permanent transition animations, use the function
 
 It is recommended to add new transition animations using the function 
 
-	func AddTransition(view View, subviewID, tag string, animation Animation) bool
+	func AddTransition(view View, subviewID, tag string, animation AnimationProperty) bool
 
 Calling this function is equivalent to the following code
 
@@ -5124,7 +5163,7 @@ Get lists of listeners for transition animation events using functions:
 
 ### Animation script
 
-An animation script describes a more complex animation than a transition animation. To do this, additional properties are added to Animation:
+An animation script describes a more complex animation than a transition animation. To do this, additional properties are added to AnimationProperty:
 
 #### "property" property
 
@@ -5190,12 +5229,12 @@ backward playback of the sequence. It can take the following values:
 
 #### Animation start
 
-To start the animation script, you must assign the interface created by Animation to the "animation" property 
-(the AnimationTag constant). If the View is already displayed on the screen, then the animation starts immediately
+To start the animation script, you must assign the interface created by AnimationProperty to the "animation" property 
+(the Animation constant). If the View is already displayed on the screen, then the animation starts immediately
 (taking into account the specified delay), otherwise the animation starts as soon as the View is displayed 
 on the screen.
 
-The "animation" property can be assigned Animation and [] Animation, ie. you can run several animations 
+The "animation" property can be assigned AnimationProperty and [] AnimationProperty, ie. you can run several animations 
 at the same time for one View
 
 Example,
@@ -5208,12 +5247,12 @@ Example,
 			90: rui.Px(220),
 		}
 	}
-	animation := rui.NewAnimation(rui.Params{
+	animation := rui.NewAnimationProperty(rui.Params{
 		rui.PropertyTag:    []rui.AnimatedProperty{prop},
 		rui.Duration:       2,
 		rui.TimingFunction: LinearTiming,
 	})
-	rui.Set(view, "subview", rui.AnimationTag, animation)
+	rui.Set(view, "subview", rui.Animation, animation)
 
 #### "animation-paused" property
 

absoluteLayout.go

@@ -2,7 +2,7 @@ package rui
 
 import "strings"
 
-// AbsoluteLayout - list-container of View
+// AbsoluteLayout represent an AbsoluteLayout view where child views can be arbitrary positioned
 type AbsoluteLayout interface {
 	ViewsContainer
 }
@@ -20,7 +20,8 @@ func NewAbsoluteLayout(session Session, params Params) AbsoluteLayout {
 }
 
 func newAbsoluteLayout(session Session) View {
-	return NewAbsoluteLayout(session, nil)
+	//return NewAbsoluteLayout(session, nil)
+	return new(absoluteLayoutData)
 }
 
 // Init initialize fields of ViewsContainer by default values
@@ -34,7 +35,7 @@ func (layout *absoluteLayoutData) htmlSubviews(self View, buffer *strings.Builde
 	if layout.views != nil {
 		for _, view := range layout.views {
 			view.addToCSSStyle(map[string]string{`position`: `absolute`})
-			viewHTML(view, buffer)
+			viewHTML(view, buffer, "")
 		}
 	}
 }

angleUnit.go

@@ -11,43 +11,51 @@ import (
 // Can take the following values: Radian, Degree, Gradian, and Turn
 type AngleUnitType uint8
 
+// Constants which represent values or the [AngleUnitType]
 const (
 	// Radian - angle in radians
 	Radian AngleUnitType = 0
+
 	// Radian - angle in radians * π
 	PiRadian AngleUnitType = 1
+
 	// Degree - angle in degrees
 	Degree AngleUnitType = 2
+
 	// Gradian - angle in gradian (1⁄400 of a full circle)
 	Gradian AngleUnitType = 3
+
 	// Turn - angle in turns (1 turn = 360 degree)
 	Turn AngleUnitType = 4
 )
 
-// AngleUnit describe a size (Value field) and size unit (Type field).
+// AngleUnit used to represent an angular values
 type AngleUnit struct {
-	Type  AngleUnitType
+	// Type of the angle value
+	Type AngleUnitType
+
+	// Value of the angle in Type units
 	Value float64
 }
 
 // Deg creates AngleUnit with Degree type
-func Deg(value float64) AngleUnit {
-	return AngleUnit{Type: Degree, Value: value}
+func Deg[T float64 | float32 | int | int8 | int16 | int32 | int64 | uint | uint8 | uint16 | uint32 | uint64](value T) AngleUnit {
+	return AngleUnit{Type: Degree, Value: float64(value)}
 }
 
 // Rad create AngleUnit with Radian type
-func Rad(value float64) AngleUnit {
-	return AngleUnit{Type: Radian, Value: value}
+func Rad[T float64 | float32 | int | int8 | int16 | int32 | int64 | uint | uint8 | uint16 | uint32 | uint64](value T) AngleUnit {
+	return AngleUnit{Type: Radian, Value: float64(value)}
 }
 
 // PiRad create AngleUnit with PiRadian type
-func PiRad(value float64) AngleUnit {
-	return AngleUnit{Type: PiRadian, Value: value}
+func PiRad[T float64 | float32 | int | int8 | int16 | int32 | int64 | uint | uint8 | uint16 | uint32 | uint64](value T) AngleUnit {
+	return AngleUnit{Type: PiRadian, Value: float64(value)}
 }
 
 // Grad create AngleUnit with Gradian type
-func Grad(value float64) AngleUnit {
-	return AngleUnit{Type: Gradian, Value: value}
+func Grad[T float64 | float32 | int | int8 | int16 | int32 | int64 | uint | uint8 | uint16 | uint32 | uint64](value T) AngleUnit {
+	return AngleUnit{Type: Gradian, Value: float64(value)}
 }
 
 // Equal compare two AngleUnit. Return true if AngleUnit are equal

animationEvents.go

@@ -1,176 +1,259 @@
 package rui
 
-import "strings"
-
+// Constants which describe values for view's animation events properties
 const (
 	// TransitionRunEvent is the constant for "transition-run-event" property tag.
-	// The "transition-run-event" is fired when a transition is first created,
-	// i.e. before any transition delay has begun.
-	TransitionRunEvent = "transition-run-event"
+	//
+	// Used by View:
+	// Is fired when a transition is first created, i.e. before any transition delay has begun.
+	//
+	// General listener format:
+	//  func(view rui.View, propertyName rui.PropertyName).
+	//
+	// where:
+	//   - view - Interface of a view which generated this event,
+	//   - propertyName - Name of the property.
+	//
+	// Allowed listener formats:
+	//  func(view rui.View),
+	//  func(propertyName rui.PropertyName)
+	//  func().
+	TransitionRunEvent PropertyName = "transition-run-event"
 
-	// TransitionStartEvent is the constant for "transition-end-event" property tag.
-	// The "transition-start-event" is fired when a transition has actually started,
-	// i.e., after "delay" has ended.
-	TransitionStartEvent = "transition-start-event"
+	// TransitionStartEvent is the constant for "transition-start-event" property tag.
+	//
+	// Used by View:
+	// Is fired when a transition has actually started, i.e., after "delay" has ended.
+	//
+	// General listener format:
+	//  func(view rui.View, propertyName rui.PropertyName).
+	//
+	// where:
+	//   - view - Interface of a view which generated this event,
+	//   - propertyName - Name of the property.
+	//
+	// Allowed listener formats:
+	//  func(view rui.View)
+	//  func(propertyName rui.PropertyName)
+	//  func()
+	TransitionStartEvent PropertyName = "transition-start-event"
 
 	// TransitionEndEvent is the constant for "transition-end-event" property tag.
-	// The "transition-end-event" is fired when a transition has completed.
-	TransitionEndEvent = "transition-end-event"
+	//
+	// Used by View:
+	// Is fired when a transition has completed.
+	//
+	// General listener format:
+	//  func(view rui.View, propertyName rui.PropertyName).
+	//
+	// where:
+	//   - view - Interface of a view which generated this event,
+	//   - propertyName - Name of the property.
+	//
+	// Allowed listener formats:
+	//  func(view rui.View)
+	//  func(propertyName rui.PropertyName)
+	//  func()
+	TransitionEndEvent PropertyName = "transition-end-event"
 
 	// TransitionCancelEvent is the constant for "transition-cancel-event" property tag.
-	// The "transition-cancel-event" is fired when a transition is cancelled. The transition is cancelled when:
-	// * A new property transition has begun.
-	// * The "visibility" property is set to "gone".
-	// * The transition is stopped before it has run to completion, e.g. by moving the mouse off a hover-transitioning view.
-	TransitionCancelEvent = "transition-cancel-event"
+	//
+	// Used by View:
+	// Is fired when a transition is cancelled. The transition is cancelled when:
+	//   - A new property transition has begun.
+	//   - The "visibility" property is set to "gone".
+	//   - The transition is stopped before it has run to completion, e.g. by moving the mouse off a hover-transitioning view.
+	//
+	// General listener format:
+	//  func(view rui.View, propertyName rui.PropertyName).
+	//
+	// where:
+	//   - view - Interface of a view which generated this event,
+	//   - propertyName - Name of the property.
+	//
+	// Allowed listener formats:
+	//  func(view rui.View)
+	//  func(propertyName rui.PropertyName)
+	//  func()
+	TransitionCancelEvent PropertyName = "transition-cancel-event"
 
 	// AnimationStartEvent is the constant for "animation-start-event" property tag.
-	// The "animation-start-event" is fired when an animation has started.
-	// If there is an animation-delay, this event will fire once the delay period has expired.
-	AnimationStartEvent = "animation-start-event"
+	//
+	// Used by View:
+	// Fired when an animation has started. If there is an "animation-delay", this event will fire once the delay period has
+	// expired.
+	//
+	// General listener format:
+	//  func(view rui.View, animationId string).
+	//
+	// where:
+	//   - view - Interface of a view which generated this event,
+	//   - animationId - Id of the animation.
+	//
+	// Allowed listener formats:
+	//  func(view rui.View)
+	//  func(animationId string)
+	//  func()
+	AnimationStartEvent PropertyName = "animation-start-event"
 
 	// AnimationEndEvent is the constant for "animation-end-event" property tag.
-	// The "animation-end-event" is fired when an animation has completed.
-	// If the animation aborts before reaching completion, such as if the element is removed
-	// or the animation is removed from the element, the "animation-end-event" is not fired.
-	AnimationEndEvent = "animation-end-event"
+	//
+	// Used by View:
+	// Fired when an animation has completed. If the animation aborts before reaching completion, such as if the element is
+	// removed or the animation is removed from the element, the "animation-end-event" is not fired.
+	//
+	// General listener format:
+	//  func(view rui.View, animationId string).
+	//
+	// where:
+	//   - view - Interface of a view which generated this event,
+	//   - animationId - Id of the animation.
+	//
+	// Allowed listener formats:
+	//  func(view rui.View)
+	//  func(animationId string)
+	//  func()
+	AnimationEndEvent PropertyName = "animation-end-event"
 
 	// AnimationCancelEvent is the constant for "animation-cancel-event" property tag.
-	// The "animation-cancel-event" is fired when an animation unexpectedly aborts.
-	// In other words, any time it stops running without sending the "animation-end-event".
-	// This might happen when the animation-name is changed such that the animation is removed,
-	// or when the animating view is hidden. Therefore, either directly or because any of its
-	// containing views are hidden.
-	// The event is not supported by all browsers.
-	AnimationCancelEvent = "animation-cancel-event"
+	//
+	// Used by View:
+	// Fired when an animation unexpectedly aborts. In other words, any time it stops running without sending the
+	// "animation-end-event". This might happen when the animation-name is changed such that the animation is removed, or when
+	// the animating view is hidden. Therefore, either directly or because any of its containing views are hidden. The event
+	// is not supported by all browsers.
+	//
+	// General listener format:
+	//  func(view rui.View, animationId string).
+	//
+	// where:
+	//   - view - Interface of a view which generated this event,
+	//   - animationId - Id of the animation.
+	//
+	// Allowed listener formats:
+	//  func(view rui.View)
+	//  func(animationId string)
+	//  func()
+	AnimationCancelEvent PropertyName = "animation-cancel-event"
 
 	// AnimationIterationEvent is the constant for "animation-iteration-event" property tag.
-	// The "animation-iteration-event" is fired when an iteration of an animation ends,
-	// and another one begins. This event does not occur at the same time as the animation end event,
-	// and therefore does not occur for animations with an "iteration-count" of one.
-	AnimationIterationEvent = "animation-iteration-event"
+	//
+	// Used by View:
+	// Fired when an iteration of an animation ends, and another one begins. This event does not occur at the same time as the
+	// animation end event, and therefore does not occur for animations with an "iteration-count" of one.
+	//
+	// General listener format:
+	//  func(view rui.View, animationId string).
+	//
+	// where:
+	//   - view - Interface of a view which generated this event,
+	//   - animationId - Id of the animation.
+	//
+	// Allowed listener formats:
+	//  func(view rui.View)
+	//  func(animationId string)
+	//  func()
+	AnimationIterationEvent PropertyName = "animation-iteration-event"
 )
 
-var transitionEvents = map[string]struct{ jsEvent, jsFunc string }{
-	TransitionRunEvent:    {jsEvent: "ontransitionrun", jsFunc: "transitionRunEvent"},
-	TransitionStartEvent:  {jsEvent: "ontransitionstart", jsFunc: "transitionStartEvent"},
-	TransitionEndEvent:    {jsEvent: "ontransitionend", jsFunc: "transitionEndEvent"},
-	TransitionCancelEvent: {jsEvent: "ontransitioncancel", jsFunc: "transitionCancelEvent"},
-}
-
-func (view *viewData) setTransitionListener(tag string, value any) bool {
-	listeners, ok := valueToEventListeners[View, string](value)
-	if !ok {
-		notCompatibleType(tag, value)
-		return false
-	}
-
-	if listeners == nil {
-		view.removeTransitionListener(tag)
-	} else if js, ok := transitionEvents[tag]; ok {
-		view.properties[tag] = listeners
-		if view.created {
-			view.session.updateProperty(view.htmlID(), js.jsEvent, js.jsFunc+"(this, event)")
+/*
+func setTransitionListener(properties Properties, tag PropertyName, value any) bool {
+	if listeners, ok := valueToOneArgEventListeners[View, string](value); ok {
+		if len(listeners) == 0 {
+			properties.setRaw(tag, nil)
+		} else {
+			properties.setRaw(tag, listeners)
 		}
-	} else {
-		return false
+		return true
 	}
-	return true
+	notCompatibleType(tag, value)
+	return false
 }
 
-func (view *viewData) removeTransitionListener(tag string) {
+func (view *viewData) removeTransitionListener(tag PropertyName) {
 	delete(view.properties, tag)
 	if view.created {
-		if js, ok := transitionEvents[tag]; ok {
+		if js, ok := eventJsFunc[tag]; ok {
 			view.session.removeProperty(view.htmlID(), js.jsEvent)
 		}
 	}
 }
 
 func transitionEventsHtml(view View, buffer *strings.Builder) {
-	for tag, js := range transitionEvents {
+	for _, tag := range []PropertyName{TransitionRunEvent, TransitionStartEvent, TransitionEndEvent, TransitionCancelEvent} {
 		if value := view.getRaw(tag); value != nil {
-			if listeners, ok := value.([]func(View, string)); ok && len(listeners) > 0 {
-				buffer.WriteString(js.jsEvent)
-				buffer.WriteString(`="`)
-				buffer.WriteString(js.jsFunc)
-				buffer.WriteString(`(this, event)" `)
+			if js, ok := eventJsFunc[tag]; ok {
+				if listeners, ok := value.([]func(View, string)); ok && len(listeners) > 0 {
+					buffer.WriteString(js.jsEvent)
+					buffer.WriteString(`="`)
+					buffer.WriteString(js.jsFunc)
+					buffer.WriteString(`(this, event)" `)
+				}
 			}
 		}
 	}
 }
+*/
 
-func (view *viewData) handleTransitionEvents(tag string, data DataObject) {
-	if property, ok := data.PropertyValue("property"); ok {
+func (view *viewData) handleTransitionEvents(tag PropertyName, data DataObject) {
+	if propertyName, ok := data.PropertyValue("property"); ok {
+		property := PropertyName(propertyName)
 		if tag == TransitionEndEvent || tag == TransitionCancelEvent {
 			if animation, ok := view.singleTransition[property]; ok {
 				delete(view.singleTransition, property)
-				if animation != nil {
-					view.transitions[property] = animation
-				} else {
-					delete(view.transitions, property)
-				}
-				view.updateTransitionCSS()
+				setTransition(view, property, animation)
+				session := view.session
+				session.updateCSSProperty(view.htmlID(), "transition", transitionCSS(view, session))
 			}
 		}
 
-		for _, listener := range getEventListeners[View, string](view, nil, tag) {
+		for _, listener := range getOneArgEventListeners[View, PropertyName](view, nil, tag) {
 			listener(view, property)
 		}
 	}
 }
 
-var animationEvents = map[string]struct{ jsEvent, jsFunc string }{
-	AnimationStartEvent:     {jsEvent: "onanimationstart", jsFunc: "animationStartEvent"},
-	AnimationEndEvent:       {jsEvent: "onanimationend", jsFunc: "animationEndEvent"},
-	AnimationIterationEvent: {jsEvent: "onanimationiteration", jsFunc: "animationIterationEvent"},
-	AnimationCancelEvent:    {jsEvent: "onanimationcancel", jsFunc: "animationCancelEvent"},
-}
-
-func (view *viewData) setAnimationListener(tag string, value any) bool {
-	listeners, ok := valueToEventListeners[View, string](value)
-	if !ok {
+/*
+	func setAnimationListener(properties Properties, tag PropertyName, value any) bool {
+		if listeners, ok := valueToOneArgEventListeners[View, string](value); ok {
+			if len(listeners) == 0 {
+				properties.setRaw(tag, nil)
+			} else {
+				properties.setRaw(tag, listeners)
+			}
+			return true
+		}
 		notCompatibleType(tag, value)
 		return false
 	}
 
-	if listeners == nil {
-		view.removeAnimationListener(tag)
-	} else if js, ok := animationEvents[tag]; ok {
-		view.properties[tag] = listeners
-		if view.created {
-			view.session.updateProperty(view.htmlID(), js.jsEvent, js.jsFunc+"(this, event)")
-		}
-	} else {
-		return false
-	}
-	return true
-}
-
-func (view *viewData) removeAnimationListener(tag string) {
+func (view *viewData) removeAnimationListener(tag PropertyName) {
 	delete(view.properties, tag)
 	if view.created {
-		if js, ok := animationEvents[tag]; ok {
+		if js, ok := eventJsFunc[tag]; ok {
 			view.session.removeProperty(view.htmlID(), js.jsEvent)
 		}
 	}
 }
 
 func animationEventsHtml(view View, buffer *strings.Builder) {
-	for tag, js := range animationEvents {
+	for _, tag := range []PropertyName{AnimationStartEvent, AnimationEndEvent, AnimationIterationEvent, AnimationCancelEvent} {
 		if value := view.getRaw(tag); value != nil {
-			if listeners, ok := value.([]func(View)); ok && len(listeners) > 0 {
-				buffer.WriteString(js.jsEvent)
-				buffer.WriteString(`="`)
-				buffer.WriteString(js.jsFunc)
-				buffer.WriteString(`(this, event)" `)
+			if js, ok := eventJsFunc[tag]; ok {
+				if listeners, ok := value.([]func(View, string)); ok && len(listeners) > 0 {
+					buffer.WriteString(js.jsEvent)
+					buffer.WriteString(`="`)
+					buffer.WriteString(js.jsFunc)
+					buffer.WriteString(`(this, event)" `)
+				}
 			}
 		}
 	}
 }
+*/
 
-func (view *viewData) handleAnimationEvents(tag string, data DataObject) {
-	if listeners := getEventListeners[View, string](view, nil, tag); len(listeners) > 0 {
+func (view *viewData) handleAnimationEvents(tag PropertyName, data DataObject) {
+	if listeners := getOneArgEventListeners[View, string](view, nil, tag); len(listeners) > 0 {
 		id := ""
 		if name, ok := data.PropertyValue("name"); ok {
 			for _, animation := range GetAnimation(view) {
@@ -189,54 +272,54 @@ func (view *viewData) handleAnimationEvents(tag string, data DataObject) {
 // If there are no listeners then the empty list is returned.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetTransitionRunListeners(view View, subviewID ...string) []func(View, string) {
-	return getEventListeners[View, string](view, subviewID, TransitionRunEvent)
+	return getOneArgEventListeners[View, string](view, subviewID, TransitionRunEvent)
 }
 
 // GetTransitionStartListeners returns the "transition-start-event" listener list.
 // If there are no listeners then the empty list is returned.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetTransitionStartListeners(view View, subviewID ...string) []func(View, string) {
-	return getEventListeners[View, string](view, subviewID, TransitionStartEvent)
+	return getOneArgEventListeners[View, string](view, subviewID, TransitionStartEvent)
 }
 
 // GetTransitionEndListeners returns the "transition-end-event" listener list.
 // If there are no listeners then the empty list is returned.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetTransitionEndListeners(view View, subviewID ...string) []func(View, string) {
-	return getEventListeners[View, string](view, subviewID, TransitionEndEvent)
+	return getOneArgEventListeners[View, string](view, subviewID, TransitionEndEvent)
 }
 
 // GetTransitionCancelListeners returns the "transition-cancel-event" listener list.
 // If there are no listeners then the empty list is returned.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetTransitionCancelListeners(view View, subviewID ...string) []func(View, string) {
-	return getEventListeners[View, string](view, subviewID, TransitionCancelEvent)
+	return getOneArgEventListeners[View, string](view, subviewID, TransitionCancelEvent)
 }
 
 // GetAnimationStartListeners returns the "animation-start-event" listener list.
 // If there are no listeners then the empty list is returned.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetAnimationStartListeners(view View, subviewID ...string) []func(View, string) {
-	return getEventListeners[View, string](view, subviewID, AnimationStartEvent)
+	return getOneArgEventListeners[View, string](view, subviewID, AnimationStartEvent)
 }
 
 // GetAnimationEndListeners returns the "animation-end-event" listener list.
 // If there are no listeners then the empty list is returned.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetAnimationEndListeners(view View, subviewID ...string) []func(View, string) {
-	return getEventListeners[View, string](view, subviewID, AnimationEndEvent)
+	return getOneArgEventListeners[View, string](view, subviewID, AnimationEndEvent)
 }
 
 // GetAnimationCancelListeners returns the "animation-cancel-event" listener list.
 // If there are no listeners then the empty list is returned.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetAnimationCancelListeners(view View, subviewID ...string) []func(View, string) {
-	return getEventListeners[View, string](view, subviewID, AnimationCancelEvent)
+	return getOneArgEventListeners[View, string](view, subviewID, AnimationCancelEvent)
 }
 
 // GetAnimationIterationListeners returns the "animation-iteration-event" listener list.
 // If there are no listeners then the empty list is returned.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetAnimationIterationListeners(view View, subviewID ...string) []func(View, string) {
-	return getEventListeners[View, string](view, subviewID, AnimationIterationEvent)
+	return getOneArgEventListeners[View, string](view, subviewID, AnimationIterationEvent)
 }

animationRun.go

@@ -0,0 +1,139 @@
+package rui
+
+func (animation *animationData) Start(view View, listener func(view View, animation AnimationProperty, event PropertyName)) bool {
+	if view == nil {
+		ErrorLog("nil View in animation.Start() function")
+		return false
+	}
+	if !animation.hasAnimatedProperty() {
+		return false
+	}
+
+	animation.view = view
+	animation.listener = listener
+
+	animation.oldAnimation = nil
+	if value := view.Get(Animation); value != nil {
+		if oldAnimation, ok := value.([]AnimationProperty); ok && len(oldAnimation) > 0 {
+			animation.oldAnimation = oldAnimation
+		}
+	}
+
+	animation.oldListeners = map[PropertyName][]func(View, PropertyName){}
+
+	setListeners := func(event PropertyName, listener func(View, PropertyName)) {
+		var listeners []func(View, PropertyName) = nil
+		if value := view.Get(event); value != nil {
+			if oldListeners, ok := value.([]func(View, PropertyName)); ok && len(oldListeners) > 0 {
+				listeners = oldListeners
+			}
+		}
+
+		if listeners == nil {
+			view.Set(event, listener)
+		} else {
+			animation.oldListeners[event] = listeners
+			view.Set(event, append(listeners, listener))
+		}
+	}
+
+	setListeners(AnimationStartEvent, animation.onAnimationStart)
+	setListeners(AnimationEndEvent, animation.onAnimationEnd)
+	setListeners(AnimationCancelEvent, animation.onAnimationCancel)
+	setListeners(AnimationIterationEvent, animation.onAnimationIteration)
+
+	view.Set(Animation, animation)
+	return true
+}
+
+func (animation *animationData) finish() {
+	if animation.view != nil {
+		for _, event := range []PropertyName{AnimationStartEvent, AnimationEndEvent, AnimationCancelEvent, AnimationIterationEvent} {
+			if listeners, ok := animation.oldListeners[event]; ok {
+				animation.view.Set(event, listeners)
+			} else {
+				animation.view.Remove(event)
+			}
+		}
+
+		if animation.oldAnimation != nil {
+			animation.view.Set(Animation, animation.oldAnimation)
+			animation.oldAnimation = nil
+		} else {
+			animation.view.Set(Animation, "")
+		}
+
+		animation.oldListeners = map[PropertyName][]func(View, PropertyName){}
+
+		animation.view = nil
+		animation.listener = nil
+	}
+}
+
+func (animation *animationData) Stop() {
+	animation.onAnimationCancel(animation.view, "")
+}
+
+func (animation *animationData) Pause() {
+	if animation.view != nil {
+		animation.view.Set(AnimationPaused, true)
+	}
+}
+
+func (animation *animationData) Resume() {
+	if animation.view != nil {
+		animation.view.Remove(AnimationPaused)
+	}
+}
+
+func (animation *animationData) onAnimationStart(view View, _ PropertyName) {
+	if animation.view != nil && animation.listener != nil {
+		animation.listener(animation.view, animation, AnimationStartEvent)
+	}
+}
+
+func (animation *animationData) onAnimationEnd(view View, _ PropertyName) {
+	if animation.view != nil {
+		animationView := animation.view
+		listener := animation.listener
+
+		if value, ok := animation.properties[PropertyTag]; ok {
+			if props, ok := value.([]AnimatedProperty); ok {
+				for _, prop := range props {
+					animationView.setRaw(prop.Tag, prop.To)
+				}
+			}
+		}
+
+		animation.finish()
+		if listener != nil {
+			listener(animationView, animation, AnimationEndEvent)
+		}
+	}
+}
+
+func (animation *animationData) onAnimationIteration(view View, _ PropertyName) {
+	if animation.view != nil && animation.listener != nil {
+		animation.listener(animation.view, animation, AnimationIterationEvent)
+	}
+}
+
+func (animation *animationData) onAnimationCancel(view View, _ PropertyName) {
+	if animation.view != nil {
+		animationView := animation.view
+		listener := animation.listener
+
+		if value, ok := animation.properties[PropertyTag]; ok {
+			if props, ok := value.([]AnimatedProperty); ok {
+				for _, prop := range props {
+					animationView.Set(prop.Tag, prop.To)
+				}
+			}
+		}
+
+		animation.finish()
+		if listener != nil {
+			listener(animationView, animation, AnimationCancelEvent)
+		}
+	}
+}

appServer.go

@@ -415,6 +415,7 @@ func StartApp(addr string, createContentFunc func(Session) SessionContent, param
 	}
 }
 
+// FinishApp finishes application
 func FinishApp() {
 	for _, app := range apps {
 		app.Finish()
@@ -422,6 +423,8 @@ func FinishApp() {
 	apps = []*application{}
 }
 
+// OpenBrowser open browser with specific URL locally. Useful for applications which run on local machine
+// or for debug purposes.
 func OpenBrowser(url string) bool {
 	var err error
 

appWasm.go

@@ -141,7 +141,7 @@ func (app *wasmApp) init(params AppParams) {
 	div := document.Call("createElement", "div")
 	div.Set("className", "ruiRoot")
 	div.Set("id", "ruiRootView")
-	viewHTML(app.session.RootView(), buffer)
+	viewHTML(app.session.RootView(), buffer, "")
 	div.Set("innerHTML", buffer.String())
 	body.Call("appendChild", div)
 

app_scripts.js

@@ -215,6 +215,21 @@ function appendToInnerHTML(elementId, content) {
 	}
 }
 
+function appendToInputValue(elementId, content) {
+	const element = document.getElementById(elementId);
+	if (element) {
+		element.value += content;
+		scanElementsSize();
+	}
+}
+
+function removeView(elementId) {
+	const element = document.getElementById(elementId);
+	if (element) {
+		element.remove()
+	}
+}
+
 function setDisabled(elementId, disabled) {
 	const element = document.getElementById(elementId);
 	if (element) {
@@ -251,22 +266,22 @@ function activateTab(layoutId, tabNumber) {
 	if (element) {
 		const currentNumber = element.getAttribute("data-current");
 		if (currentNumber != tabNumber) {
-			function setTab(number, styleProperty, display) {
+			function setTab(number, styleProperty, visibility) {
 				const tab = document.getElementById(layoutId + '-' + number);
 				if (tab) {	
 					tab.className = element.getAttribute(styleProperty);
 					const page = document.getElementById(tab.getAttribute("data-view"));
 					if (page) {
-						page.style.display = display;
+						page.style.visibility = visibility
 					}
 					return
 				}
 				const page = document.getElementById(layoutId + "-page" + number);
 				if (page) {
-					page.style.display = display;
+					page.style.visibility = visibility
 				}
 			}
-			setTab(currentNumber, "data-inactiveTabStyle", "none")
+			setTab(currentNumber, "data-inactiveTabStyle", "hidden")
 			setTab(tabNumber, "data-activeTabStyle", "");
 			element.setAttribute("data-current", tabNumber);
 			scanElementsSize()
@@ -615,21 +630,11 @@ function listItemClickEvent(element, event) {
 		return
 	}
 
-	let selected = false;
-	if (element.classList) {
-		const focusStyle = getListFocusedItemStyle(element);
-		const blurStyle = getListSelectedItemStyle(element);
-		selected = (element.classList.contains(focusStyle) || element.classList.contains(blurStyle));
-	} 
-
 	const list = element.parentNode.parentNode
 	if (list) {
-		if (!selected) {
-			selectListItem(list, element, true)
-		}
-
-		const message = "itemClick{session=" + sessionID + ",id=" + list.id + "}"
-		sendMessage(message);
+		const number = getListItemNumber(element.id)
+		selectListItem(list, element)
+		sendMessage("itemClick{session=" + sessionID + ",id=" + list.id + ",number=" + number + "}");
 	}
 }
 
@@ -656,7 +661,7 @@ function getListSelectedItemStyle(element) {
 	return getStyleAttribute(element, "data-bluritemstyle", "ruiListItemSelected");
 }
 
-function selectListItem(element, item, needSendMessage) {
+function selectListItem(element, item) {
 	const currentId = element.getAttribute("data-current");
 	let message;
 	const focusStyle = getListFocusedItemStyle(element);
@@ -668,9 +673,7 @@ function selectListItem(element, item, needSendMessage) {
 			if (current.classList) {
 				current.classList.remove(focusStyle, blurStyle);
 			}
-			if (sendMessage) {
-				message = "itemUnselected{session=" + sessionID + ",id=" + element.id + "}";
-			}
+			message = "itemUnselected{session=" + sessionID + ",id=" + element.id + "}";
 		}
 	}
 
@@ -685,12 +688,10 @@ function selectListItem(element, item, needSendMessage) {
 			}
 		}
 
-		element.setAttribute("data-current", item.id);
-		if (sendMessage) {
-			const number = getListItemNumber(item.id)
-			if (number != undefined) {
-				message = "itemSelected{session=" + sessionID + ",id=" + element.id + ",number=" + number + "}";
-			}
+		element.setAttribute("data-current", item.id);		
+		const number = getListItemNumber(item.id)
+		if (number != undefined) {
+			message = "itemSelected{session=" + sessionID + ",id=" + element.id + ",number=" + number + "}";
 		}
 
 		if (item.scrollIntoViewIfNeeded) {
@@ -698,29 +699,9 @@ function selectListItem(element, item, needSendMessage) {
 		} else {
 			item.scrollIntoView({block: "nearest", inline: "nearest"});
 		}
-	/*
-		let left = item.offsetLeft - element.offsetLeft;
-		if (left < element.scrollLeft) {
-			element.scrollLeft = left;
-		}
-
-		let top = item.offsetTop - element.offsetTop;
-		if (top < element.scrollTop) {
-			element.scrollTop = top;
-		}
-		
-		let right = left + item.offsetWidth;
-		if (right > element.scrollLeft + element.clientWidth) {
-			element.scrollLeft = right - element.clientWidth;
-		}
-
-		let bottom = top + item.offsetHeight
-		if (bottom > element.scrollTop + element.clientHeight) {
-			element.scrollTop = bottom - element.clientHeight;
-		}*/
 	}
 
-	if (needSendMessage && message != undefined) {
+	if (message != undefined) {
 		sendMessage(message);
 	}
 	scanElementsSize();
@@ -849,7 +830,7 @@ function listViewKeyDownEvent(element, event) {
 			switch (key) {
 				case " ": 
 				case "Enter":
-					const message = "itemClick{session=" + sessionID + ",id=" + element.id + "}";
+					const message = "itemClick{session=" + sessionID + ",id=" + element.id + ",number=" + getListItemNumber(currentId) + "}";
 					sendMessage(message);
 					break;
 
@@ -889,7 +870,7 @@ function listViewKeyDownEvent(element, event) {
 					return;
 			}
 			if (item && item !== current) {
-				selectListItem(element, item, true);
+				selectListItem(element, item);
 			}
 		} else {
 			switch (key) {
@@ -908,7 +889,7 @@ function listViewKeyDownEvent(element, event) {
 						if (item.getAttribute("data-disabled") == "1") {
 							continue;
 						}
-						selectListItem(element, item, true);
+						selectListItem(element, item);
 						return;
 					}
 					break;
@@ -1982,7 +1963,15 @@ function getCanvasContext(elementId) {
 
 function localStorageSet(key, value) {
 	try {
-		localStorage.setItem(key, value)
+		localStorage.setItem(key, value);
+	} catch (err) {
+		sendMessage("storageError{session=" + sessionID + ", error=`" + err + "`}")
+	}
+}
+
+function localStorageRemove(key) {
+	try {
+		localStorage.removeItem(key);
 	} catch (err) {
 		sendMessage("storageError{session=" + sessionID + ", error=`" + err + "`}")
 	}
@@ -1990,7 +1979,7 @@ function localStorageSet(key, value) {
 
 function localStorageClear() {
 	try {
-		localStorage.setItem(key, value)
+		localStorage.clear();
 	} catch (err) {
 		sendMessage("storageError{session=" + sessionID + ", error=`" + err + "`}")
 	}
@@ -2128,3 +2117,11 @@ function setCssVar(tag, value) {
 		root.style.setProperty(tag, value);
 	}
 }
+
+function createPath2D(svg) {
+	if (svg) {
+		return new Path2D(svg);
+	} else {
+		return new Path2D();
+	}
+}

app_styles.css

@@ -79,7 +79,7 @@ ul:focus {
 }
 
 .ruiPopupLayer {
-  background-color: rgba(128,128,128,0.1);
+  /*background-color: rgba(128,128,128,0.1);*/
   position: absolute;
   top: 0px;
   bottom: 0px;
@@ -147,6 +147,11 @@ ul:focus {
 
 .ruiListLayout {
   display: flex;
+  overflow: auto;
+}
+
+.ruiColumnLayout {
+  overflow: auto;
 }
 
 .ruiStackLayout {
@@ -181,6 +186,14 @@ ul:focus {
   overflow: auto;
 }
 
+.hiddenMarker {
+  list-style: none;
+}
+
+.hiddenMarker::-webkit-details-marker {
+  display: none;
+}
+
 /*
 @media (prefers-color-scheme: light) {
   body {

application.go

@@ -14,10 +14,14 @@ var appStyles string
 //go:embed defaultTheme.rui
 var defaultThemeText string
 
-// Application - app interface
+// Application represent generic application interface, see also [Session]
 type Application interface {
+	// Finish finishes the application
 	Finish()
+
+	// Params returns application parameters set by StartApp function
 	Params() AppParams
+
 	removeSession(id int)
 }
 

audioPlayer.go

@@ -1,5 +1,6 @@
 package rui
 
+// AudioPlayer is a type of a [View] which can play audio files
 type AudioPlayer interface {
 	MediaPlayer
 }
@@ -12,13 +13,12 @@ type audioPlayerData struct {
 func NewAudioPlayer(session Session, params Params) AudioPlayer {
 	view := new(audioPlayerData)
 	view.init(session)
-	view.tag = "AudioPlayer"
 	setInitParams(view, params)
 	return view
 }
 
 func newAudioPlayer(session Session) View {
-	return NewAudioPlayer(session, nil)
+	return new(audioPlayerData) // NewAudioPlayer(session, nil)
 }
 
 func (player *audioPlayerData) init(session Session) {
@@ -26,10 +26,6 @@ func (player *audioPlayerData) init(session Session) {
 	player.tag = "AudioPlayer"
 }
 
-func (player *audioPlayerData) String() string {
-	return getViewString(player, nil)
-}
-
 func (player *audioPlayerData) htmlTag() string {
 	return "audio"
 }

background.go

@@ -2,107 +2,65 @@ package rui
 
 import (
 	"fmt"
-	"strings"
 )
 
 const (
-	// NoRepeat is value of the Repeat property of an background image:
-	// The image is not repeated (and hence the background image painting area
-	// will not necessarily be entirely covered). The position of the non-repeated
-	// background image is defined by the background-position CSS property.
-	NoRepeat = 0
-	// RepeatXY is value of the Repeat property of an background image:
-	// The image is repeated as much as needed to cover the whole background
-	// image painting area. The last image will be clipped if it doesn't fit.
-	RepeatXY = 1
-	// RepeatX is value of the Repeat property of an background image:
-	// The image is repeated horizontally as much as needed to cover
-	// the whole width background image painting area. The image is not repeated vertically.
-	// The last image will be clipped if it doesn't fit.
-	RepeatX = 2
-	// RepeatY is value of the Repeat property of an background image:
-	// The image is repeated vertically as much as needed to cover
-	// the whole height background image painting area. The image is not repeated horizontally.
-	// The last image will be clipped if it doesn't fit.
-	RepeatY = 3
-	// RepeatRound is value of the Repeat property of an background image:
-	// As the allowed space increases in size, the repeated images will stretch (leaving no gaps)
-	// until there is room (space left >= half of the image width) for another one to be added.
-	// When the next image is added, all of the current ones compress to allow room.
-	RepeatRound = 4
-	// RepeatSpace is value of the Repeat property of an background image:
-	// The image is repeated as much as possible without clipping. The first and last images
-	// are pinned to either side of the element, and whitespace is distributed evenly between the images.
-	RepeatSpace = 5
+	// BorderBox is the value of the following properties:
+	//   - BackgroundClip - The background extends to the outside edge of the border (but underneath the border in z-ordering).
+	//   - BackgroundOrigin - The background is positioned relative to the border box.
+	//   - MaskClip - The painted content is clipped to the border box.
+	//   - MaskOrigin - The mask is positioned relative to the border box.
+	BorderBox = 0
 
-	// ScrollAttachment is value of the Attachment property of an background image:
-	// The background is fixed relative to the element itself and does not scroll with its contents.
-	// (It is effectively attached to the element's border.)
-	ScrollAttachment = 0
-	// FixedAttachment is value of the Attachment property of an background image:
-	// The background is fixed relative to the viewport. Even if an element has
-	// a scrolling mechanism, the background doesn't move with the element.
-	FixedAttachment = 1
-	// LocalAttachment is value of the Attachment property of an background image:
-	// The background is fixed relative to the element's contents. If the element has a scrolling mechanism,
-	// the background scrolls with the element's contents, and the background painting area
-	// and background positioning area are relative to the scrollable area of the element
-	// rather than to the border framing them.
-	LocalAttachment = 2
+	// PaddingBox is value of the BackgroundClip and MaskClip property:
+	//   - BackgroundClip - The background extends to the outside edge of the padding. No background is drawn beneath the border.
+	//   - BackgroundOrigin - The background is positioned relative to the padding box.
+	//   - MaskClip - The painted content is clipped to the padding box.
+	//   - MaskOrigin - The mask is positioned relative to the padding box.
+	PaddingBox = 1
 
-	// BorderBoxClip is value of the BackgroundClip property:
-	// The background extends to the outside edge of the border (but underneath the border in z-ordering).
-	BorderBoxClip = 0
-	// PaddingBoxClip is value of the BackgroundClip property:
-	// The background extends to the outside edge of the padding. No background is drawn beneath the border.
-	PaddingBoxClip = 1
-	// ContentBoxClip is value of the BackgroundClip property:
-	// The background is painted within (clipped to) the content box.
-	ContentBoxClip = 2
+	// ContentBox is value of the BackgroundClip and MaskClip property:
+	//   - BackgroundClip - The background is painted within (clipped to) the content box.
+	//   - BackgroundOrigin - The background is positioned relative to the content box.
+	//   - MaskClip - The painted content is clipped to the content box.
+	//   - MaskOrigin - The mask is positioned relative to the content box.
+	ContentBox = 2
 )
 
-// BackgroundElement describes the background element.
+// BackgroundElement describes the background element
 type BackgroundElement interface {
 	Properties
 	fmt.Stringer
 	stringWriter
 	cssStyle(session Session) string
+
+	// Tag returns type of the background element.
+	// Possible values are: "image", "conic-gradient", "linear-gradient" and "radial-gradient"
 	Tag() string
+
+	// Clone creates a new copy of BackgroundElement
 	Clone() BackgroundElement
 }
 
 type backgroundElement struct {
-	propertyList
+	dataProperty
 }
 
-type backgroundImage struct {
-	backgroundElement
-}
-
-// NewBackgroundImage creates the new background image
 func createBackground(obj DataObject) BackgroundElement {
 	var result BackgroundElement = nil
 
 	switch obj.Tag() {
 	case "image":
-		image := new(backgroundImage)
-		image.properties = map[string]any{}
-		result = image
+		result = NewBackgroundImage(nil)
 
 	case "linear-gradient":
-		gradient := new(backgroundLinearGradient)
-		gradient.properties = map[string]any{}
-		result = gradient
+		result = NewBackgroundLinearGradient(nil)
 
 	case "radial-gradient":
-		gradient := new(backgroundRadialGradient)
-		gradient.properties = map[string]any{}
-		result = gradient
+		result = NewBackgroundRadialGradient(nil)
 
 	case "conic-gradient":
-		gradient := new(backgroundConicGradient)
-		gradient.properties = map[string]any{}
-		result = gradient
+		result = NewBackgroundConicGradient(nil)
 
 	default:
 		return nil
@@ -112,7 +70,7 @@ func createBackground(obj DataObject) BackgroundElement {
 	for i := 0; i < count; i++ {
 		if node := obj.Property(i); node.Type() == TextNode {
 			if value := node.Text(); value != "" {
-				result.Set(node.Tag(), value)
+				result.Set(PropertyName(node.Tag()), value)
 			}
 		}
 	}
@@ -120,144 +78,240 @@ func createBackground(obj DataObject) BackgroundElement {
 	return result
 }
 
-// NewBackgroundImage creates the new background image
-func NewBackgroundImage(params Params) BackgroundElement {
-	result := new(backgroundImage)
-	result.properties = map[string]any{}
-	for tag, value := range params {
-		result.Set(tag, value)
-	}
-	return result
-}
+func parseBackgroundValue(value any) []BackgroundElement {
 
-func (image *backgroundImage) Tag() string {
-	return "image"
-}
+	switch value := value.(type) {
+	case BackgroundElement:
+		return []BackgroundElement{value}
 
-func (image *backgroundImage) Clone() BackgroundElement {
-	result := NewBackgroundImage(nil)
-	for tag, value := range image.properties {
-		result.setRaw(tag, value)
-	}
-	return result
-}
+	case []BackgroundElement:
+		return value
 
-func (image *backgroundImage) normalizeTag(tag string) string {
-	tag = strings.ToLower(tag)
-	switch tag {
-	case "source":
-		tag = Source
+	case []DataValue:
+		background := []BackgroundElement{}
+		for _, el := range value {
+			if el.IsObject() {
+				if element := createBackground(el.Object()); element != nil {
+					background = append(background, element)
+				} else {
+					return nil
+				}
+			} else if obj := ParseDataText(el.Value()); obj != nil {
+				if element := createBackground(obj); element != nil {
+					background = append(background, element)
+				} else {
+					return nil
+				}
+			} else {
+				return nil
+			}
+		}
+		return background
 
-	case Fit:
-		tag = backgroundFit
-
-	case HorizontalAlign:
-		tag = ImageHorizontalAlign
-
-	case VerticalAlign:
-		tag = ImageVerticalAlign
-	}
-
-	return tag
-}
-
-func (image *backgroundImage) Set(tag string, value any) bool {
-	tag = image.normalizeTag(tag)
-	switch tag {
-	case Attachment, Width, Height, Repeat, ImageHorizontalAlign, ImageVerticalAlign,
-		backgroundFit, Source:
-		return image.backgroundElement.Set(tag, value)
-	}
-
-	return false
-}
-
-func (image *backgroundImage) Get(tag string) any {
-	return image.backgroundElement.Get(image.normalizeTag(tag))
-}
-
-func (image *backgroundImage) cssStyle(session Session) string {
-	if src, ok := imageProperty(image, Source, session); ok && src != "" {
-		buffer := allocStringBuilder()
-		defer freeStringBuilder(buffer)
-
-		buffer.WriteString(`url(`)
-		buffer.WriteString(src)
-		buffer.WriteRune(')')
-
-		attachment, _ := enumProperty(image, Attachment, session, NoRepeat)
-		values := enumProperties[Attachment].values
-		if attachment > 0 && attachment < len(values) {
-			buffer.WriteRune(' ')
-			buffer.WriteString(values[attachment])
+	case DataObject:
+		if element := createBackground(value); element != nil {
+			return []BackgroundElement{element}
 		}
 
-		align, _ := enumProperty(image, ImageHorizontalAlign, session, LeftAlign)
-		values = enumProperties[ImageHorizontalAlign].values
-		if align >= 0 && align < len(values) {
-			buffer.WriteRune(' ')
-			buffer.WriteString(values[align])
-		} else {
-			buffer.WriteString(` left`)
+	case []DataObject:
+		background := []BackgroundElement{}
+		for _, obj := range value {
+			if element := createBackground(obj); element != nil {
+				background = append(background, element)
+			} else {
+				return nil
+			}
 		}
+		return background
 
-		align, _ = enumProperty(image, ImageVerticalAlign, session, TopAlign)
-		values = enumProperties[ImageVerticalAlign].values
-		if align >= 0 && align < len(values) {
-			buffer.WriteRune(' ')
-			buffer.WriteString(values[align])
-		} else {
-			buffer.WriteString(` top`)
-		}
-
-		fit, _ := enumProperty(image, backgroundFit, session, NoneFit)
-		values = enumProperties[backgroundFit].values
-		if fit > 0 && fit < len(values) {
-
-			buffer.WriteString(` / `)
-			buffer.WriteString(values[fit])
-
-		} else {
-
-			width, _ := sizeProperty(image, Width, session)
-			height, _ := sizeProperty(image, Height, session)
-
-			if width.Type != Auto || height.Type != Auto {
-				buffer.WriteString(` / `)
-				buffer.WriteString(width.cssString("auto", session))
-				buffer.WriteRune(' ')
-				buffer.WriteString(height.cssString("auto", session))
+	case string:
+		if obj := ParseDataText(value); obj != nil {
+			if element := createBackground(obj); element != nil {
+				return []BackgroundElement{element}
 			}
 		}
 
-		repeat, _ := enumProperty(image, Repeat, session, NoRepeat)
-		values = enumProperties[Repeat].values
-		if repeat >= 0 && repeat < len(values) {
-			buffer.WriteRune(' ')
-			buffer.WriteString(values[repeat])
-		} else {
-			buffer.WriteString(` no-repeat`)
+	case []string:
+		elements := make([]BackgroundElement, 0, len(value))
+		for _, element := range value {
+			if obj := ParseDataText(element); obj != nil {
+				if element := createBackground(obj); element != nil {
+					elements = append(elements, element)
+				} else {
+					return nil
+				}
+			} else {
+				return nil
+			}
 		}
+		return elements
+
+	case []any:
+		elements := make([]BackgroundElement, 0, len(value))
+		for _, element := range value {
+			switch element := element.(type) {
+			case BackgroundElement:
+				elements = append(elements, element)
+
+			case string:
+				if obj := ParseDataText(element); obj != nil {
+					if element := createBackground(obj); element != nil {
+						elements = append(elements, element)
+					} else {
+						return nil
+					}
+				} else {
+					return nil
+				}
+
+			default:
+				return nil
+			}
+		}
+		return elements
 
-		return buffer.String()
 	}
 
+	return nil
+}
+
+func setBackgroundProperty(properties Properties, tag PropertyName, value any) []PropertyName {
+
+	background := parseBackgroundValue(value)
+	if background == nil {
+		notCompatibleType(tag, value)
+		return nil
+	}
+
+	if len(background) > 0 {
+		properties.setRaw(tag, background)
+	} else if properties.getRaw(tag) != nil {
+		properties.setRaw(tag, nil)
+	} else {
+		return []PropertyName{}
+	}
+
+	return []PropertyName{tag}
+}
+
+func backgroundCSS(properties Properties, session Session) string {
+
+	if value := properties.getRaw(Background); value != nil {
+		if backgrounds, ok := value.([]BackgroundElement); ok && len(backgrounds) > 0 {
+			buffer := allocStringBuilder()
+			defer freeStringBuilder(buffer)
+
+			for _, background := range backgrounds {
+				if value := background.cssStyle(session); value != "" {
+					if buffer.Len() > 0 {
+						buffer.WriteString(", ")
+					}
+					buffer.WriteString(value)
+				}
+			}
+
+			if buffer.Len() > 0 {
+				backgroundColor, _ := colorProperty(properties, BackgroundColor, session)
+				if backgroundColor != 0 {
+					buffer.WriteRune(' ')
+					buffer.WriteString(backgroundColor.cssString())
+				}
+				return buffer.String()
+			}
+		}
+	}
 	return ""
 }
 
-func (image *backgroundImage) writeString(buffer *strings.Builder, indent string) {
-	image.writeToBuffer(buffer, indent, image.Tag(), []string{
-		Source,
-		Width,
-		Height,
-		ImageHorizontalAlign,
-		ImageVerticalAlign,
-		backgroundFit,
-		Repeat,
-		Attachment,
-	})
+func maskCSS(properties Properties, session Session) string {
+
+	if value := properties.getRaw(Mask); value != nil {
+		if backgrounds, ok := value.([]BackgroundElement); ok && len(backgrounds) > 0 {
+			buffer := allocStringBuilder()
+			defer freeStringBuilder(buffer)
+
+			for _, background := range backgrounds {
+				if value := background.cssStyle(session); value != "" {
+					if buffer.Len() > 0 {
+						buffer.WriteString(", ")
+					}
+					buffer.WriteString(value)
+				}
+			}
+			return buffer.String()
+		}
+	}
+	return ""
 }
 
-func (image *backgroundImage) String() string {
-	return runStringWriter(image)
+func backgroundStyledPropery(view View, subviewID []string, tag PropertyName) []BackgroundElement {
+	var background []BackgroundElement = nil
+
+	if view = getSubview(view, subviewID); view != nil {
+		if value := view.getRaw(tag); value != nil {
+			if backgrounds, ok := value.([]BackgroundElement); ok {
+				background = backgrounds
+			}
+		} else if value := valueFromStyle(view, tag); value != nil {
+			background = parseBackgroundValue(value)
+		}
+	}
+
+	if count := len(background); count > 0 {
+		result := make([]BackgroundElement, count)
+		copy(result, background)
+		return result
+	}
+
+	return []BackgroundElement{}
+}
+
+// GetBackground returns the view background.
+//
+// If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
+func GetBackground(view View, subviewID ...string) []BackgroundElement {
+	return backgroundStyledPropery(view, subviewID, Background)
+}
+
+// GetMask returns the view mask.
+//
+// If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
+func GetMask(view View, subviewID ...string) []BackgroundElement {
+	return backgroundStyledPropery(view, subviewID, Mask)
+}
+
+// GetBackgroundClip returns a "background-clip" of the subview. Returns one of next values:
+//
+//	BorderBox (0), PaddingBox (1), ContentBox (2)
+//
+// If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
+func GetBackgroundClip(view View, subviewID ...string) int {
+	return enumStyledProperty(view, subviewID, BackgroundClip, 0, false)
+}
+
+// GetBackgroundOrigin returns a "background-origin" of the subview. Returns one of next values:
+//
+//	BorderBox (0), PaddingBox (1), ContentBox (2)
+//
+// If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
+func GetBackgroundOrigin(view View, subviewID ...string) int {
+	return enumStyledProperty(view, subviewID, BackgroundOrigin, 0, false)
+}
+
+// GetMaskClip returns a "mask-clip" of the subview. Returns one of next values:
+//
+//	BorderBox (0), PaddingBox (1), ContentBox (2)
+//
+// If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
+func GetMaskClip(view View, subviewID ...string) int {
+	return enumStyledProperty(view, subviewID, MaskClip, 0, false)
+}
+
+// GetMaskOrigin returns a "mask-origin" of the subview. Returns one of next values:
+//
+//	BorderBox (0), PaddingBox (1), ContentBox (2)
+//
+// If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
+func GetMaskOrigin(view View, subviewID ...string) int {
+	return enumStyledProperty(view, subviewID, MaskOrigin, 0, false)
 }

backgroundConicGradient.go

@@ -19,15 +19,23 @@ type BackgroundGradientAngle struct {
 }
 
 // NewBackgroundConicGradient creates the new background conic gradient
+//
+// The following properties can be used:
+//   - "gradient" [Gradient] - Describes gradient stop points. This is a mandatory property while describing background gradients.
+//   - "center-x" [CenterX] - center X point of the gradient.
+//   - "center-y" [CenterY] - center Y point of the gradient.
+//   - "from" [From] - start angle position of the gradient.
+//   - "repeating" [Repeating] - Defines whether stop points needs to be repeated after the last one.
 func NewBackgroundConicGradient(params Params) BackgroundElement {
 	result := new(backgroundConicGradient)
-	result.properties = map[string]any{}
+	result.init()
 	for tag, value := range params {
 		result.Set(tag, value)
 	}
 	return result
 }
 
+// String convert internal representation of [BackgroundGradientAngle] into a string.
 func (point *BackgroundGradientAngle) String() string {
 	result := "black"
 	if point.Color != nil {
@@ -47,7 +55,6 @@ func (point *BackgroundGradientAngle) String() string {
 
 		case AngleUnit:
 			result += " " + value.String()
-
 		}
 	}
 
@@ -72,6 +79,11 @@ func (point *BackgroundGradientAngle) color(session Session) (Color, bool) {
 
 		case Color:
 			return color, true
+
+		default:
+			if n, ok := isInt(color); ok {
+				return Color(n), true
+			}
 		}
 	}
 	return 0, false
@@ -114,6 +126,15 @@ func (point *BackgroundGradientAngle) cssString(session Session, buffer *strings
 	}
 }
 
+func (gradient *backgroundConicGradient) init() {
+	gradient.backgroundElement.init()
+	gradient.normalize = normalizeConicGradientTag
+	gradient.set = backgroundConicGradientSet
+	gradient.supportedProperties = []PropertyName{
+		CenterX, CenterY, Repeating, From, Gradient,
+	}
+}
+
 func (gradient *backgroundConicGradient) Tag() string {
 	return "conic-gradient"
 }
@@ -126,8 +147,8 @@ func (image *backgroundConicGradient) Clone() BackgroundElement {
 	return result
 }
 
-func (gradient *backgroundConicGradient) normalizeTag(tag string) string {
-	tag = strings.ToLower(tag)
+func normalizeConicGradientTag(tag PropertyName) PropertyName {
+	tag = defaultNormalize(tag)
 	switch tag {
 	case "x-center":
 		tag = CenterX
@@ -139,18 +160,50 @@ func (gradient *backgroundConicGradient) normalizeTag(tag string) string {
 	return tag
 }
 
-func (gradient *backgroundConicGradient) Set(tag string, value any) bool {
-	tag = gradient.normalizeTag(tag)
+func backgroundConicGradientSet(properties Properties, tag PropertyName, value any) []PropertyName {
 	switch tag {
-	case CenterX, CenterY, Repeating, From:
-		return gradient.propertyList.Set(tag, value)
-
 	case Gradient:
-		return gradient.setGradient(value)
+		switch value := value.(type) {
+		case string:
+			if value == "" {
+				return propertiesRemove(properties, tag)
+			}
+
+			if strings.Contains(value, ",") || strings.Contains(value, " ") {
+				if vector := parseGradientText(value); vector != nil {
+					properties.setRaw(Gradient, vector)
+					return []PropertyName{tag}
+				}
+			} else if isConstantName(value) {
+				properties.setRaw(Gradient, value)
+				return []PropertyName{tag}
+			}
+
+			ErrorLogF(`Invalid conic gradient: "%s"`, value)
+
+		case []BackgroundGradientAngle:
+			count := len(value)
+			if count < 2 {
+				ErrorLog("The gradient must contain at least 2 points")
+				return nil
+			}
+
+			for i, point := range value {
+				if point.Color == nil {
+					ErrorLogF("Invalid %d element of the conic gradient: Color is nil", i)
+					return nil
+				}
+			}
+			properties.setRaw(Gradient, value)
+			return []PropertyName{tag}
+
+		default:
+			notCompatibleType(tag, value)
+		}
+		return nil
 	}
 
-	ErrorLogF(`"%s" property is not supported by BackgroundConicGradient`, tag)
-	return false
+	return propertiesSet(properties, tag, value)
 }
 
 func (gradient *backgroundConicGradient) stringToAngle(text string) (any, bool) {
@@ -215,57 +268,6 @@ func (gradient *backgroundConicGradient) parseGradientText(value string) []Backg
 	}
 	return vector
 }
-
-func (gradient *backgroundConicGradient) setGradient(value any) bool {
-	if value == nil {
-		delete(gradient.properties, Gradient)
-		return true
-	}
-
-	switch value := value.(type) {
-	case string:
-		if value == "" {
-			delete(gradient.properties, Gradient)
-			return true
-		}
-
-		if strings.Contains(value, ",") || strings.Contains(value, " ") {
-			if vector := gradient.parseGradientText(value); vector != nil {
-				gradient.properties[Gradient] = vector
-				return true
-			}
-			return false
-		} else if value[0] == '@' {
-			gradient.properties[Gradient] = value
-			return true
-		}
-
-		ErrorLogF(`Invalid conic gradient: "%s"`, value)
-		return false
-
-	case []BackgroundGradientAngle:
-		count := len(value)
-		if count < 2 {
-			ErrorLog("The gradient must contain at least 2 points")
-			return false
-		}
-
-		for i, point := range value {
-			if point.Color == nil {
-				ErrorLogF("Invalid %d element of the conic gradient: Color is nil", i)
-				return false
-			}
-		}
-		gradient.properties[Gradient] = value
-		return true
-	}
-	return false
-}
-
-func (gradient *backgroundConicGradient) Get(tag string) any {
-	return gradient.backgroundElement.Get(gradient.normalizeTag(tag))
-}
-
 func (gradient *backgroundConicGradient) cssStyle(session Session) string {
 
 	points := []BackgroundGradientAngle{}
@@ -338,7 +340,7 @@ func (gradient *backgroundConicGradient) cssStyle(session Session) string {
 }
 
 func (gradient *backgroundConicGradient) writeString(buffer *strings.Builder, indent string) {
-	gradient.writeToBuffer(buffer, indent, gradient.Tag(), []string{
+	gradient.writeToBuffer(buffer, indent, gradient.Tag(), []PropertyName{
 		Gradient,
 		CenterX,
 		CenterY,

backgroundGradient.go

@@ -1,665 +0,0 @@
-package rui
-
-import "strings"
-
-const (
-
-	// ToTopGradient is value of the Direction property of a linear gradient. The value is equivalent to the 0deg angle
-	ToTopGradient = 0
-	// ToRightTopGradient is value of the Direction property of a linear gradient.
-	ToRightTopGradient = 1
-	// ToRightGradient is value of the Direction property of a linear gradient. The value is equivalent to the 90deg angle
-	ToRightGradient = 2
-	// ToRightBottomGradient is value of the Direction property of a linear gradient.
-	ToRightBottomGradient = 3
-	// ToBottomGradient is value of the Direction property of a linear gradient. The value is equivalent to the 180deg angle
-	ToBottomGradient = 4
-	// ToLeftBottomGradient is value of the Direction property of a linear gradient.
-	ToLeftBottomGradient = 5
-	// ToLeftGradient is value of the Direction property of a linear gradient. The value is equivalent to the 270deg angle
-	ToLeftGradient = 6
-	// ToLeftTopGradient is value of the Direction property of a linear gradient.
-	ToLeftTopGradient = 7
-
-	// EllipseGradient is value of the Shape property of a radial gradient background:
-	// the shape is an axis-aligned ellipse
-	EllipseGradient = 0
-	// CircleGradient is value of the Shape property of a radial gradient background:
-	// the gradient's shape is a circle with constant radius
-	CircleGradient = 1
-
-	// ClosestSideGradient is value of the Radius property of a radial gradient background:
-	// The gradient's ending shape meets the side of the box closest to its center (for circles)
-	// or meets both the vertical and horizontal sides closest to the center (for ellipses).
-	ClosestSideGradient = 0
-	// ClosestCornerGradient is value of the Radius property of a radial gradient background:
-	// The gradient's ending shape is sized so that it exactly meets the closest corner
-	// of the box from its center.
-	ClosestCornerGradient = 1
-	// FarthestSideGradient is value of the Radius property of a radial gradient background:
-	// Similar to closest-side, except the ending shape is sized to meet the side of the box
-	// farthest from its center (or vertical and horizontal sides).
-	FarthestSideGradient = 2
-	// FarthestCornerGradient is value of the Radius property of a radial gradient background:
-	// The default value, the gradient's ending shape is sized so that it exactly meets
-	// the farthest corner of the box from its center.
-	FarthestCornerGradient = 3
-)
-
-// BackgroundGradientPoint define point on gradient straight line
-type BackgroundGradientPoint struct {
-	// Color - the color of the point. Must not be nil.
-	// Can take a value of Color type or string (color constant or textual description of the color)
-	Color any
-	// Pos - the distance from the start of the gradient straight line. Optional (may be nil).
-	// Can take a value of SizeUnit type or string (angle constant or textual description of the SizeUnit)
-	Pos any
-}
-
-type backgroundGradient struct {
-	backgroundElement
-}
-
-type backgroundLinearGradient struct {
-	backgroundGradient
-}
-
-type backgroundRadialGradient struct {
-	backgroundGradient
-}
-
-// NewBackgroundLinearGradient creates the new background linear gradient
-func NewBackgroundLinearGradient(params Params) BackgroundElement {
-	result := new(backgroundLinearGradient)
-	result.properties = map[string]any{}
-	for tag, value := range params {
-		result.Set(tag, value)
-	}
-	return result
-}
-
-// NewBackgroundRadialGradient creates the new background radial gradient
-func NewBackgroundRadialGradient(params Params) BackgroundElement {
-	result := new(backgroundRadialGradient)
-	result.properties = map[string]any{}
-	for tag, value := range params {
-		result.Set(tag, value)
-	}
-	return result
-}
-
-func (gradient *backgroundGradient) parseGradientText(value string) []BackgroundGradientPoint {
-	elements := strings.Split(value, ",")
-	count := len(elements)
-	if count < 2 {
-		ErrorLog("The gradient must contain at least 2 points")
-		return nil
-	}
-
-	points := make([]BackgroundGradientPoint, count)
-	for i, element := range elements {
-		if !points[i].setValue(element) {
-			ErrorLogF(`Invalid %d element of the conic gradient: "%s"`, i, element)
-			return nil
-		}
-	}
-	return points
-}
-
-func (gradient *backgroundGradient) Set(tag string, value any) bool {
-
-	switch tag = strings.ToLower(tag); tag {
-	case Repeating:
-		return gradient.setBoolProperty(tag, value)
-
-	case Gradient:
-		switch value := value.(type) {
-		case string:
-			if value != "" {
-				if strings.Contains(value, " ") || strings.Contains(value, ",") {
-					if points := gradient.parseGradientText(value); len(points) >= 2 {
-						gradient.properties[Gradient] = points
-						return true
-					}
-				} else if value[0] == '@' {
-					gradient.properties[Gradient] = value
-					return true
-				}
-			}
-
-		case []BackgroundGradientPoint:
-			if len(value) >= 2 {
-				gradient.properties[Gradient] = value
-				return true
-			}
-
-		case []Color:
-			count := len(value)
-			if count >= 2 {
-				points := make([]BackgroundGradientPoint, count)
-				for i, color := range value {
-					points[i].Color = color
-				}
-				gradient.properties[Gradient] = points
-				return true
-			}
-
-		case []GradientPoint:
-			count := len(value)
-			if count >= 2 {
-				points := make([]BackgroundGradientPoint, count)
-				for i, point := range value {
-					points[i].Color = point.Color
-					points[i].Pos = Percent(point.Offset * 100)
-				}
-				gradient.properties[Gradient] = points
-				return true
-			}
-		}
-
-		ErrorLogF("Invalid gradient %v", value)
-		return false
-	}
-
-	ErrorLogF("Property %s is not supported by a background gradient", tag)
-	return false
-}
-
-func (point *BackgroundGradientPoint) setValue(text string) bool {
-	text = strings.Trim(text, " ")
-
-	colorText := text
-	pointText := ""
-
-	if index := strings.Index(text, " "); index > 0 {
-		colorText = text[:index]
-		pointText = strings.Trim(text[index+1:], " ")
-	}
-
-	if colorText == "" {
-		return false
-	}
-
-	if colorText[0] == '@' {
-		point.Color = colorText
-	} else if color, ok := StringToColor(colorText); ok {
-		point.Color = color
-	} else {
-		return false
-	}
-
-	if pointText == "" {
-		point.Pos = nil
-	} else if pointText[0] == '@' {
-		point.Pos = pointText
-	} else if pos, ok := StringToSizeUnit(pointText); ok {
-		point.Pos = pos
-	} else {
-		return false
-	}
-
-	return true
-}
-
-func (point *BackgroundGradientPoint) color(session Session) (Color, bool) {
-	if point.Color != nil {
-		switch color := point.Color.(type) {
-		case string:
-			if color != "" {
-				if color[0] == '@' {
-					if clr, ok := session.Color(color[1:]); ok {
-						return clr, true
-					}
-				} else {
-					if clr, ok := StringToColor(color); ok {
-						return clr, true
-					}
-				}
-			}
-
-		case Color:
-			return color, true
-		}
-	}
-	return 0, false
-}
-
-func (point *BackgroundGradientPoint) String() string {
-	result := "black"
-	if point.Color != nil {
-		switch color := point.Color.(type) {
-		case string:
-			result = color
-
-		case Color:
-			result = color.String()
-		}
-	}
-
-	if point.Pos != nil {
-		switch value := point.Pos.(type) {
-		case string:
-			result += " " + value
-
-		case SizeUnit:
-			if value.Type != Auto {
-				result += " " + value.String()
-			}
-		}
-	}
-
-	return result
-}
-
-func (gradient *backgroundGradient) writeGradient(session Session, buffer *strings.Builder) bool {
-
-	value, ok := gradient.properties[Gradient]
-	if !ok {
-		return false
-	}
-
-	var points []BackgroundGradientPoint = nil
-
-	switch value := value.(type) {
-	case string:
-		if value != "" && value[0] == '@' {
-			if text, ok := session.Constant(value[1:]); ok {
-				points = gradient.parseGradientText(text)
-			}
-		}
-
-	case []BackgroundGradientPoint:
-		points = value
-	}
-
-	if len(points) > 0 {
-		for i, point := range points {
-			if i > 0 {
-				buffer.WriteString(`, `)
-			}
-
-			if color, ok := point.color(session); ok {
-				buffer.WriteString(color.cssString())
-			} else {
-				return false
-			}
-
-			if point.Pos != nil {
-				switch value := point.Pos.(type) {
-				case string:
-					if value != "" {
-						if value, ok := session.resolveConstants(value); ok {
-							if pos, ok := StringToSizeUnit(value); ok && pos.Type != Auto {
-								buffer.WriteRune(' ')
-								buffer.WriteString(pos.cssString("", session))
-							}
-						}
-					}
-
-				case SizeUnit:
-					if value.Type != Auto {
-						buffer.WriteRune(' ')
-						buffer.WriteString(value.cssString("", session))
-					}
-				}
-			}
-		}
-		return true
-	}
-
-	return false
-}
-
-func (gradient *backgroundLinearGradient) Tag() string {
-	return "linear-gradient"
-}
-
-func (image *backgroundLinearGradient) Clone() BackgroundElement {
-	result := NewBackgroundLinearGradient(nil)
-	for tag, value := range image.properties {
-		result.setRaw(tag, value)
-	}
-	return result
-}
-
-func (gradient *backgroundLinearGradient) Set(tag string, value any) bool {
-	if strings.ToLower(tag) == Direction {
-		switch value := value.(type) {
-		case AngleUnit:
-			gradient.properties[Direction] = value
-			return true
-
-		case string:
-			if gradient.setSimpleProperty(tag, value) {
-				return true
-			}
-			if angle, ok := StringToAngleUnit(value); ok {
-				gradient.properties[Direction] = angle
-				return true
-			}
-		}
-		return gradient.setEnumProperty(tag, value, enumProperties[Direction].values)
-	}
-
-	return gradient.backgroundGradient.Set(tag, value)
-}
-
-func (gradient *backgroundLinearGradient) cssStyle(session Session) string {
-	buffer := allocStringBuilder()
-	defer freeStringBuilder(buffer)
-
-	if repeating, _ := boolProperty(gradient, Repeating, session); repeating {
-		buffer.WriteString(`repeating-linear-gradient(`)
-	} else {
-		buffer.WriteString(`linear-gradient(`)
-	}
-
-	if value, ok := gradient.properties[Direction]; ok {
-		switch value := value.(type) {
-		case string:
-			if text, ok := session.resolveConstants(value); ok {
-				direction := enumProperties[Direction]
-				if n, ok := enumStringToInt(text, direction.values, false); ok {
-					buffer.WriteString(direction.cssValues[n])
-					buffer.WriteString(", ")
-				} else {
-					if angle, ok := StringToAngleUnit(text); ok {
-						buffer.WriteString(angle.cssString())
-						buffer.WriteString(", ")
-					} else {
-						ErrorLog(`Invalid linear gradient direction: ` + text)
-					}
-				}
-			} else {
-				ErrorLog(`Invalid linear gradient direction: ` + value)
-			}
-
-		case int:
-			values := enumProperties[Direction].cssValues
-			if value >= 0 && value < len(values) {
-				buffer.WriteString(values[value])
-				buffer.WriteString(", ")
-			} else {
-				ErrorLogF(`Invalid linear gradient direction: %d`, value)
-			}
-
-		case AngleUnit:
-			buffer.WriteString(value.cssString())
-			buffer.WriteString(", ")
-		}
-	}
-
-	if !gradient.writeGradient(session, buffer) {
-		return ""
-	}
-
-	buffer.WriteString(") ")
-	return buffer.String()
-}
-
-func (gradient *backgroundLinearGradient) writeString(buffer *strings.Builder, indent string) {
-	gradient.writeToBuffer(buffer, indent, gradient.Tag(), []string{
-		Gradient,
-		Repeating,
-		Direction,
-	})
-}
-
-func (gradient *backgroundLinearGradient) String() string {
-	return runStringWriter(gradient)
-}
-
-func (gradient *backgroundRadialGradient) Tag() string {
-	return "radial-gradient"
-}
-
-func (image *backgroundRadialGradient) Clone() BackgroundElement {
-	result := NewBackgroundRadialGradient(nil)
-	for tag, value := range image.properties {
-		result.setRaw(tag, value)
-	}
-	return result
-}
-
-func (gradient *backgroundRadialGradient) normalizeTag(tag string) string {
-	tag = strings.ToLower(tag)
-	switch tag {
-	case Radius:
-		tag = RadialGradientRadius
-
-	case Shape:
-		tag = RadialGradientShape
-
-	case "x-center":
-		tag = CenterX
-
-	case "y-center":
-		tag = CenterY
-	}
-
-	return tag
-}
-
-func (gradient *backgroundRadialGradient) Set(tag string, value any) bool {
-	tag = gradient.normalizeTag(tag)
-	switch tag {
-	case RadialGradientRadius:
-		switch value := value.(type) {
-		case []SizeUnit:
-			switch len(value) {
-			case 0:
-				delete(gradient.properties, RadialGradientRadius)
-				return true
-
-			case 1:
-				if value[0].Type == Auto {
-					delete(gradient.properties, RadialGradientRadius)
-				} else {
-					gradient.properties[RadialGradientRadius] = value[0]
-				}
-				return true
-
-			default:
-				gradient.properties[RadialGradientRadius] = value
-				return true
-			}
-
-		case []any:
-			switch len(value) {
-			case 0:
-				delete(gradient.properties, RadialGradientRadius)
-				return true
-
-			case 1:
-				return gradient.Set(RadialGradientRadius, value[0])
-
-			default:
-				gradient.properties[RadialGradientRadius] = value
-				return true
-			}
-
-		case string:
-			if gradient.setSimpleProperty(RadialGradientRadius, value) {
-				return true
-			}
-			if size, err := stringToSizeUnit(value); err == nil {
-				if size.Type == Auto {
-					delete(gradient.properties, RadialGradientRadius)
-				} else {
-					gradient.properties[RadialGradientRadius] = size
-				}
-				return true
-			}
-			return gradient.setEnumProperty(RadialGradientRadius, value, enumProperties[RadialGradientRadius].values)
-
-		case SizeUnit:
-			if value.Type == Auto {
-				delete(gradient.properties, RadialGradientRadius)
-			} else {
-				gradient.properties[RadialGradientRadius] = value
-			}
-			return true
-
-		case int:
-			n := value
-			if n >= 0 && n < len(enumProperties[RadialGradientRadius].values) {
-				return gradient.propertyList.Set(RadialGradientRadius, value)
-			}
-		}
-		ErrorLogF(`Invalid value of "%s" property: %v`, tag, value)
-
-	case RadialGradientShape, CenterX, CenterY:
-		return gradient.propertyList.Set(tag, value)
-	}
-
-	return gradient.backgroundGradient.Set(tag, value)
-}
-
-func (gradient *backgroundRadialGradient) Get(tag string) any {
-	return gradient.backgroundGradient.Get(gradient.normalizeTag(tag))
-}
-
-func (gradient *backgroundRadialGradient) cssStyle(session Session) string {
-	buffer := allocStringBuilder()
-	defer freeStringBuilder(buffer)
-
-	if repeating, _ := boolProperty(gradient, Repeating, session); repeating {
-		buffer.WriteString(`repeating-radial-gradient(`)
-	} else {
-		buffer.WriteString(`radial-gradient(`)
-	}
-
-	var shapeText string
-	if shape, ok := enumProperty(gradient, RadialGradientShape, session, EllipseGradient); ok && shape == CircleGradient {
-		shapeText = `circle `
-	} else {
-		shapeText = `ellipse `
-	}
-
-	if value, ok := gradient.properties[RadialGradientRadius]; ok {
-		switch value := value.(type) {
-		case string:
-			if text, ok := session.resolveConstants(value); ok {
-				values := enumProperties[RadialGradientRadius]
-				if n, ok := enumStringToInt(text, values.values, false); ok {
-					buffer.WriteString(shapeText)
-					shapeText = ""
-					buffer.WriteString(values.cssValues[n])
-					buffer.WriteString(" ")
-				} else {
-					if r, ok := StringToSizeUnit(text); ok && r.Type != Auto {
-						buffer.WriteString("ellipse ")
-						shapeText = ""
-						buffer.WriteString(r.cssString("", session))
-						buffer.WriteString(" ")
-						buffer.WriteString(r.cssString("", session))
-						buffer.WriteString(" ")
-					} else {
-						ErrorLog(`Invalid radial gradient radius: ` + text)
-					}
-				}
-			} else {
-				ErrorLog(`Invalid radial gradient radius: ` + value)
-			}
-
-		case int:
-			values := enumProperties[RadialGradientRadius].cssValues
-			if value >= 0 && value < len(values) {
-				buffer.WriteString(shapeText)
-				shapeText = ""
-				buffer.WriteString(values[value])
-				buffer.WriteString(" ")
-			} else {
-				ErrorLogF(`Invalid radial gradient radius: %d`, value)
-			}
-
-		case SizeUnit:
-			if value.Type != Auto {
-				buffer.WriteString("ellipse ")
-				shapeText = ""
-				buffer.WriteString(value.cssString("", session))
-				buffer.WriteString(" ")
-				buffer.WriteString(value.cssString("", session))
-				buffer.WriteString(" ")
-			}
-
-		case []SizeUnit:
-			count := len(value)
-			if count > 2 {
-				count = 2
-			}
-			buffer.WriteString("ellipse ")
-			shapeText = ""
-			for i := 0; i < count; i++ {
-				buffer.WriteString(value[i].cssString("50%", session))
-				buffer.WriteString(" ")
-			}
-
-		case []any:
-			count := len(value)
-			if count > 2 {
-				count = 2
-			}
-			buffer.WriteString("ellipse ")
-			shapeText = ""
-			for i := 0; i < count; i++ {
-				if value[i] != nil {
-					switch value := value[i].(type) {
-					case SizeUnit:
-						buffer.WriteString(value.cssString("50%", session))
-						buffer.WriteString(" ")
-
-					case string:
-						if text, ok := session.resolveConstants(value); ok {
-							if size, err := stringToSizeUnit(text); err == nil {
-								buffer.WriteString(size.cssString("50%", session))
-								buffer.WriteString(" ")
-							} else {
-								buffer.WriteString("50% ")
-							}
-						} else {
-							buffer.WriteString("50% ")
-						}
-					}
-				} else {
-					buffer.WriteString("50% ")
-				}
-			}
-		}
-	}
-
-	x, _ := sizeProperty(gradient, CenterX, session)
-	y, _ := sizeProperty(gradient, CenterX, session)
-	if x.Type != Auto || y.Type != Auto {
-		if shapeText != "" {
-			buffer.WriteString(shapeText)
-		}
-		buffer.WriteString("at ")
-		buffer.WriteString(x.cssString("50%", session))
-		buffer.WriteString(" ")
-		buffer.WriteString(y.cssString("50%", session))
-	}
-
-	buffer.WriteString(", ")
-	if !gradient.writeGradient(session, buffer) {
-		return ""
-	}
-
-	buffer.WriteString(") ")
-
-	return buffer.String()
-}
-func (gradient *backgroundRadialGradient) writeString(buffer *strings.Builder, indent string) {
-	gradient.writeToBuffer(buffer, indent, gradient.Tag(), []string{
-		Gradient,
-		CenterX,
-		CenterY,
-		Repeating,
-		RadialGradientShape,
-		RadialGradientRadius,
-	})
-}
-
-func (gradient *backgroundRadialGradient) String() string {
-	return runStringWriter(gradient)
-}

backgroundImage.go

@@ -0,0 +1,217 @@
+package rui
+
+import (
+	"strings"
+)
+
+// Constants related to view's background description
+const (
+	// NoRepeat is value of the Repeat property of an background image:
+	//
+	// The image is not repeated (and hence the background image painting area
+	// will not necessarily be entirely covered). The position of the non-repeated
+	// background image is defined by the background-position CSS property.
+	NoRepeat = 0
+
+	// RepeatXY is value of the Repeat property of an background image:
+	//
+	// The image is repeated as much as needed to cover the whole background
+	// image painting area. The last image will be clipped if it doesn't fit.
+	RepeatXY = 1
+
+	// RepeatX is value of the Repeat property of an background image:
+	//
+	// The image is repeated horizontally as much as needed to cover
+	// the whole width background image painting area. The image is not repeated vertically.
+	// The last image will be clipped if it doesn't fit.
+	RepeatX = 2
+
+	// RepeatY is value of the Repeat property of an background image:
+	//
+	// The image is repeated vertically as much as needed to cover
+	// the whole height background image painting area. The image is not repeated horizontally.
+	// The last image will be clipped if it doesn't fit.
+	RepeatY = 3
+
+	// RepeatRound is value of the Repeat property of an background image:
+	//
+	// As the allowed space increases in size, the repeated images will stretch (leaving no gaps)
+	// until there is room (space left >= half of the image width) for another one to be added.
+	// When the next image is added, all of the current ones compress to allow room.
+	RepeatRound = 4
+
+	// RepeatSpace is value of the Repeat property of an background image:
+	//
+	// The image is repeated as much as possible without clipping. The first and last images
+	// are pinned to either side of the element, and whitespace is distributed evenly between the images.
+	RepeatSpace = 5
+
+	// ScrollAttachment is value of the Attachment property of an background image:
+	//
+	// The background is fixed relative to the element itself and does not scroll with its contents.
+	// (It is effectively attached to the element's border.)
+	ScrollAttachment = 0
+
+	// FixedAttachment is value of the Attachment property of an background image:
+	//
+	// The background is fixed relative to the viewport. Even if an element has
+	// a scrolling mechanism, the background doesn't move with the element.
+	FixedAttachment = 1
+
+	// LocalAttachment is value of the Attachment property of an background image:
+	//
+	// The background is fixed relative to the element's contents. If the element has a scrolling mechanism,
+	// the background scrolls with the element's contents, and the background painting area
+	// and background positioning area are relative to the scrollable area of the element
+	// rather than to the border framing them.
+	LocalAttachment = 2
+)
+
+type backgroundImage struct {
+	backgroundElement
+}
+
+// NewBackgroundImage creates the new background image
+//
+// The following properties can be used:
+//   - "src" [Source] - the name of the image in the "images" folder of the resources, or the URL of the image or inline-image.
+//   - "width" [Width] - the width of the image.
+//   - "height" [Height] - the height of the image.
+//   - "image-horizontal-align" [ImageHorizontalAlign] - the horizontal alignment of the image relative to view's bounds.
+//   - "image-vertical-align" [ImageVerticalAlign] - the vertical alignment of the image relative to view's  bounds.
+//   - "repeat" [Repeat] - the repetition of the image.
+//   - "fit" [Fit] - the image scaling parameters.
+//   - "attachment" [Attachment] - defines whether a background image's position is fixed within the viewport or scrolls with its containing block.
+func NewBackgroundImage(params Params) BackgroundElement {
+	result := new(backgroundImage)
+	result.init()
+	for tag, value := range params {
+		result.Set(tag, value)
+	}
+	return result
+}
+
+func (image *backgroundImage) init() {
+	image.backgroundElement.init()
+	image.normalize = normalizeBackgroundImageTag
+	image.supportedProperties = []PropertyName{
+		Attachment, Width, Height, Repeat, ImageHorizontalAlign, ImageVerticalAlign, backgroundFit, Source,
+	}
+}
+
+func (image *backgroundImage) Tag() string {
+	return "image"
+}
+
+func (image *backgroundImage) Clone() BackgroundElement {
+	result := NewBackgroundImage(nil)
+	for tag, value := range image.properties {
+		result.setRaw(tag, value)
+	}
+	return result
+}
+
+func normalizeBackgroundImageTag(tag PropertyName) PropertyName {
+	tag = defaultNormalize(tag)
+	switch tag {
+	case "source":
+		tag = Source
+
+	case Fit:
+		tag = backgroundFit
+
+	case HorizontalAlign:
+		tag = ImageHorizontalAlign
+
+	case VerticalAlign:
+		tag = ImageVerticalAlign
+	}
+
+	return tag
+}
+
+func (image *backgroundImage) cssStyle(session Session) string {
+	if src, ok := imageProperty(image, Source, session); ok && src != "" {
+		buffer := allocStringBuilder()
+		defer freeStringBuilder(buffer)
+
+		buffer.WriteString(`url(`)
+		buffer.WriteString(src)
+		buffer.WriteRune(')')
+
+		attachment, _ := enumProperty(image, Attachment, session, NoRepeat)
+		values := enumProperties[Attachment].values
+		if attachment > 0 && attachment < len(values) {
+			buffer.WriteRune(' ')
+			buffer.WriteString(values[attachment])
+		}
+
+		align, _ := enumProperty(image, ImageHorizontalAlign, session, LeftAlign)
+		values = enumProperties[ImageHorizontalAlign].values
+		if align >= 0 && align < len(values) {
+			buffer.WriteRune(' ')
+			buffer.WriteString(values[align])
+		} else {
+			buffer.WriteString(` left`)
+		}
+
+		align, _ = enumProperty(image, ImageVerticalAlign, session, TopAlign)
+		values = enumProperties[ImageVerticalAlign].values
+		if align >= 0 && align < len(values) {
+			buffer.WriteRune(' ')
+			buffer.WriteString(values[align])
+		} else {
+			buffer.WriteString(` top`)
+		}
+
+		fit, _ := enumProperty(image, backgroundFit, session, NoneFit)
+		values = enumProperties[backgroundFit].values
+		if fit > 0 && fit < len(values) {
+
+			buffer.WriteString(` / `)
+			buffer.WriteString(values[fit])
+
+		} else {
+
+			width, _ := sizeProperty(image, Width, session)
+			height, _ := sizeProperty(image, Height, session)
+
+			if width.Type != Auto || height.Type != Auto {
+				buffer.WriteString(` / `)
+				buffer.WriteString(width.cssString("auto", session))
+				buffer.WriteRune(' ')
+				buffer.WriteString(height.cssString("auto", session))
+			}
+		}
+
+		repeat, _ := enumProperty(image, Repeat, session, NoRepeat)
+		values = enumProperties[Repeat].values
+		if repeat >= 0 && repeat < len(values) {
+			buffer.WriteRune(' ')
+			buffer.WriteString(values[repeat])
+		} else {
+			buffer.WriteString(` no-repeat`)
+		}
+
+		return buffer.String()
+	}
+
+	return ""
+}
+
+func (image *backgroundImage) writeString(buffer *strings.Builder, indent string) {
+	image.writeToBuffer(buffer, indent, image.Tag(), []PropertyName{
+		Source,
+		Width,
+		Height,
+		ImageHorizontalAlign,
+		ImageVerticalAlign,
+		backgroundFit,
+		Repeat,
+		Attachment,
+	})
+}
+
+func (image *backgroundImage) String() string {
+	return runStringWriter(image)
+}

backgroundLinearGradient.go

@@ -0,0 +1,413 @@
+package rui
+
+import "strings"
+
+type LinearGradientDirectionType int
+
+// Constants related to view's background gradient description
+const (
+	// ToTopGradient is value of the Direction property of a linear gradient. The value is equivalent to the 0deg angle
+	ToTopGradient LinearGradientDirectionType = 0
+
+	// ToRightTopGradient is value of the Direction property of a linear gradient.
+	ToRightTopGradient LinearGradientDirectionType = 1
+
+	// ToRightGradient is value of the Direction property of a linear gradient. The value is equivalent to the 90deg angle
+	ToRightGradient LinearGradientDirectionType = 2
+
+	// ToRightBottomGradient is value of the Direction property of a linear gradient.
+	ToRightBottomGradient LinearGradientDirectionType = 3
+
+	// ToBottomGradient is value of the Direction property of a linear gradient. The value is equivalent to the 180deg angle
+	ToBottomGradient LinearGradientDirectionType = 4
+
+	// ToLeftBottomGradient is value of the Direction property of a linear gradient.
+	ToLeftBottomGradient LinearGradientDirectionType = 5
+
+	// ToLeftGradient is value of the Direction property of a linear gradient. The value is equivalent to the 270deg angle
+	ToLeftGradient LinearGradientDirectionType = 6
+
+	// ToLeftTopGradient is value of the Direction property of a linear gradient.
+	ToLeftTopGradient LinearGradientDirectionType = 7
+)
+
+// BackgroundGradientPoint define point on gradient straight line
+type BackgroundGradientPoint struct {
+	// Color - the color of the point. Must not be nil.
+	// Can take a value of Color type or string (color constant or textual description of the color)
+	Color any
+	// Pos - the distance from the start of the gradient straight line. Optional (may be nil).
+	// Can take a value of SizeUnit type or string (size constant or textual description of the SizeUnit)
+	Pos any
+}
+
+type backgroundGradient struct {
+	backgroundElement
+}
+
+type backgroundLinearGradient struct {
+	backgroundGradient
+}
+
+// NewBackgroundLinearGradient creates the new background linear gradient.
+//
+// The following properties can be used:
+//   - "gradient" [Gradient] - Describes gradient stop points. This is a mandatory property while describing background gradients.
+//   - "direction" [Direction] - Defines the direction of the gradient line.
+//   - "repeating" [Repeating] - Defines whether stop points needs to be repeated after the last one.
+func NewBackgroundLinearGradient(params Params) BackgroundElement {
+	result := new(backgroundLinearGradient)
+	result.init()
+	for tag, value := range params {
+		result.Set(tag, value)
+	}
+	return result
+}
+
+// NewLinearGradient creates the new background linear gradient.
+func NewLinearGradient[DirectionType LinearGradientDirectionType | AngleUnit](direction DirectionType, repeating bool, point1 GradientPoint, point2 GradientPoint, points ...GradientPoint) BackgroundElement {
+	params := Params{
+		Direction: direction,
+		Gradient:  append([]GradientPoint{point1, point2}, points...),
+	}
+	if repeating {
+		params[Repeating] = true
+	}
+	return NewBackgroundLinearGradient(params)
+}
+
+func parseGradientText(value string) []BackgroundGradientPoint {
+	elements := strings.Split(value, ",")
+	count := len(elements)
+	if count < 2 {
+		ErrorLog("The gradient must contain at least 2 points")
+		return nil
+	}
+
+	points := make([]BackgroundGradientPoint, count)
+	for i, element := range elements {
+		if !points[i].setValue(element) {
+			ErrorLogF(`Invalid %d element of the conic gradient: "%s"`, i, element)
+			return nil
+		}
+	}
+	return points
+}
+
+func backgroundGradientSet(properties Properties, tag PropertyName, value any) []PropertyName {
+
+	switch tag {
+	case Repeating:
+		return setBoolProperty(properties, tag, value)
+
+	case Gradient:
+		switch value := value.(type) {
+		case string:
+			if value != "" {
+				if strings.Contains(value, " ") || strings.Contains(value, ",") {
+					if points := parseGradientText(value); len(points) >= 2 {
+						properties.setRaw(Gradient, points)
+						return []PropertyName{tag}
+					}
+				} else if value[0] == '@' {
+					properties.setRaw(Gradient, value)
+					return []PropertyName{tag}
+				}
+			}
+
+		case []BackgroundGradientPoint:
+			if len(value) >= 2 {
+				properties.setRaw(Gradient, value)
+				return []PropertyName{tag}
+			}
+
+		case []Color:
+			count := len(value)
+			if count >= 2 {
+				points := make([]BackgroundGradientPoint, count)
+				for i, color := range value {
+					points[i].Color = color
+				}
+				properties.setRaw(Gradient, points)
+				return []PropertyName{tag}
+			}
+
+		case []GradientPoint:
+			count := len(value)
+			if count >= 2 {
+				points := make([]BackgroundGradientPoint, count)
+				for i, point := range value {
+					points[i].Color = point.Color
+					points[i].Pos = Percent(point.Offset * 100)
+				}
+				properties.setRaw(Gradient, points)
+				return []PropertyName{tag}
+			}
+		}
+
+		ErrorLogF("Invalid gradient %v", value)
+		return nil
+	}
+
+	ErrorLogF("Property %s is not supported by a background gradient", tag)
+	return nil
+}
+
+func (point *BackgroundGradientPoint) setValue(text string) bool {
+	text = strings.Trim(text, " ")
+
+	colorText := text
+	pointText := ""
+
+	if index := strings.Index(text, " "); index > 0 {
+		colorText = text[:index]
+		pointText = strings.Trim(text[index+1:], " ")
+	}
+
+	if colorText == "" {
+		return false
+	}
+
+	if colorText[0] == '@' {
+		point.Color = colorText
+	} else if color, ok := StringToColor(colorText); ok {
+		point.Color = color
+	} else {
+		return false
+	}
+
+	if pointText == "" {
+		point.Pos = nil
+	} else if pointText[0] == '@' {
+		point.Pos = pointText
+	} else if pos, ok := StringToSizeUnit(pointText); ok {
+		point.Pos = pos
+	} else {
+		return false
+	}
+
+	return true
+}
+
+func (point *BackgroundGradientPoint) color(session Session) (Color, bool) {
+	if point.Color != nil {
+		switch color := point.Color.(type) {
+		case string:
+			if color != "" {
+				if color[0] == '@' {
+					if clr, ok := session.Color(color[1:]); ok {
+						return clr, true
+					}
+				} else {
+					if clr, ok := StringToColor(color); ok {
+						return clr, true
+					}
+				}
+			}
+
+		case Color:
+			return color, true
+
+		default:
+			if n, ok := isInt(point.Color); ok {
+				return Color(n), true
+			}
+		}
+	}
+	return 0, false
+}
+
+// String convert internal representation of [BackgroundGradientPoint] into a string.
+func (point *BackgroundGradientPoint) String() string {
+	result := "black"
+	if point.Color != nil {
+		switch color := point.Color.(type) {
+		case string:
+			result = color
+
+		case Color:
+			result = color.String()
+		}
+	}
+
+	if point.Pos != nil {
+		switch value := point.Pos.(type) {
+		case string:
+			result += " " + value
+
+		case SizeUnit:
+			if value.Type != Auto {
+				result += " " + value.String()
+			}
+		}
+	}
+
+	return result
+}
+
+func (gradient *backgroundGradient) writeGradient(session Session, buffer *strings.Builder) bool {
+
+	value, ok := gradient.properties[Gradient]
+	if !ok {
+		return false
+	}
+
+	var points []BackgroundGradientPoint = nil
+
+	switch value := value.(type) {
+	case string:
+		if value != "" && value[0] == '@' {
+			if text, ok := session.Constant(value[1:]); ok {
+				points = parseGradientText(text)
+			}
+		}
+
+	case []BackgroundGradientPoint:
+		points = value
+	}
+
+	if len(points) > 0 {
+		for i, point := range points {
+			if i > 0 {
+				buffer.WriteString(`, `)
+			}
+
+			if color, ok := point.color(session); ok {
+				buffer.WriteString(color.cssString())
+			} else {
+				return false
+			}
+
+			if point.Pos != nil {
+				switch value := point.Pos.(type) {
+				case string:
+					if value != "" {
+						if value, ok := session.resolveConstants(value); ok {
+							if pos, ok := StringToSizeUnit(value); ok && pos.Type != Auto {
+								buffer.WriteRune(' ')
+								buffer.WriteString(pos.cssString("", session))
+							}
+						}
+					}
+
+				case SizeUnit:
+					if value.Type != Auto {
+						buffer.WriteRune(' ')
+						buffer.WriteString(value.cssString("", session))
+					}
+				}
+			}
+		}
+		return true
+	}
+
+	return false
+}
+
+func (gradient *backgroundLinearGradient) init() {
+	gradient.backgroundElement.init()
+	gradient.set = backgroundLinearGradientSet
+	gradient.supportedProperties = []PropertyName{Direction, Repeating, Gradient}
+}
+
+func (gradient *backgroundLinearGradient) Tag() string {
+	return "linear-gradient"
+}
+
+func (image *backgroundLinearGradient) Clone() BackgroundElement {
+	result := NewBackgroundLinearGradient(nil)
+	for tag, value := range image.properties {
+		result.setRaw(tag, value)
+	}
+	return result
+}
+
+func backgroundLinearGradientSet(properties Properties, tag PropertyName, value any) []PropertyName {
+	if tag == Direction {
+		switch value := value.(type) {
+		case AngleUnit:
+			properties.setRaw(Direction, value)
+			return []PropertyName{tag}
+
+		case string:
+			if setSimpleProperty(properties, tag, value) {
+				return []PropertyName{tag}
+			}
+			if angle, ok := StringToAngleUnit(value); ok {
+				properties.setRaw(Direction, angle)
+				return []PropertyName{tag}
+			}
+
+		case LinearGradientDirectionType:
+			return setEnumProperty(properties, tag, int(value), enumProperties[Direction].values)
+		}
+		return setEnumProperty(properties, tag, value, enumProperties[Direction].values)
+	}
+
+	return backgroundGradientSet(properties, tag, value)
+}
+
+func (gradient *backgroundLinearGradient) cssStyle(session Session) string {
+	buffer := allocStringBuilder()
+	defer freeStringBuilder(buffer)
+
+	if repeating, _ := boolProperty(gradient, Repeating, session); repeating {
+		buffer.WriteString(`repeating-linear-gradient(`)
+	} else {
+		buffer.WriteString(`linear-gradient(`)
+	}
+
+	if value, ok := gradient.properties[Direction]; ok {
+		switch value := value.(type) {
+		case string:
+			if text, ok := session.resolveConstants(value); ok {
+				direction := enumProperties[Direction]
+				if n, ok := enumStringToInt(text, direction.values, false); ok {
+					buffer.WriteString(direction.cssValues[n])
+					buffer.WriteString(", ")
+				} else {
+					if angle, ok := StringToAngleUnit(text); ok {
+						buffer.WriteString(angle.cssString())
+						buffer.WriteString(", ")
+					} else {
+						ErrorLog(`Invalid linear gradient direction: ` + text)
+					}
+				}
+			} else {
+				ErrorLog(`Invalid linear gradient direction: ` + value)
+			}
+
+		case int:
+			values := enumProperties[Direction].cssValues
+			if value >= 0 && value < len(values) {
+				buffer.WriteString(values[value])
+				buffer.WriteString(", ")
+			} else {
+				ErrorLogF(`Invalid linear gradient direction: %d`, value)
+			}
+
+		case AngleUnit:
+			buffer.WriteString(value.cssString())
+			buffer.WriteString(", ")
+		}
+	}
+
+	if !gradient.writeGradient(session, buffer) {
+		return ""
+	}
+
+	buffer.WriteString(") ")
+	return buffer.String()
+}
+
+func (gradient *backgroundLinearGradient) writeString(buffer *strings.Builder, indent string) {
+	gradient.writeToBuffer(buffer, indent, gradient.Tag(), []PropertyName{
+		Gradient,
+		Repeating,
+		Direction,
+	})
+}
+
+func (gradient *backgroundLinearGradient) String() string {
+	return runStringWriter(gradient)
+}

backgroundRadialGradient.go

@@ -0,0 +1,357 @@
+package rui
+
+import "strings"
+
+type RadialGradientRadiusType int
+
+// Constants related to view's background gradient description
+const (
+	// EllipseGradient is value of the Shape property of a radial gradient background:
+	// the shape is an axis-aligned ellipse
+	EllipseGradient = 0
+
+	// CircleGradient is value of the Shape property of a radial gradient background:
+	// the gradient's shape is a circle with constant radius
+	CircleGradient = 1
+
+	// ClosestSideGradient is value of the Radius property of a radial gradient background:
+	// The gradient's ending shape meets the side of the box closest to its center (for circles)
+	// or meets both the vertical and horizontal sides closest to the center (for ellipses).
+	ClosestSideGradient RadialGradientRadiusType = 0
+
+	// ClosestCornerGradient is value of the Radius property of a radial gradient background:
+	// The gradient's ending shape is sized so that it exactly meets the closest corner
+	// of the box from its center.
+	ClosestCornerGradient RadialGradientRadiusType = 1
+
+	// FarthestSideGradient is value of the Radius property of a radial gradient background:
+	// Similar to closest-side, except the ending shape is sized to meet the side of the box
+	// farthest from its center (or vertical and horizontal sides).
+	FarthestSideGradient RadialGradientRadiusType = 2
+
+	// FarthestCornerGradient is value of the Radius property of a radial gradient background:
+	// The default value, the gradient's ending shape is sized so that it exactly meets
+	// the farthest corner of the box from its center.
+	FarthestCornerGradient RadialGradientRadiusType = 3
+)
+
+type backgroundRadialGradient struct {
+	backgroundGradient
+}
+
+// NewBackgroundRadialGradient creates the new background radial gradient.
+//
+// The following properties can be used:
+//   - "gradient" (Gradient) - Describes gradient stop points. This is a mandatory property while describing background gradients.
+//   - "center-x" (CenterX), "center-y" (CenterY) - Defines the gradient center point cooordinates.
+//   - "radial-gradient-radius" (RadialGradientRadius) - Defines radius of the radial gradient.
+//   - "radial-gradient-shape" (RadialGradientShape) - Defines shape of the radial gradient.
+//   - "repeating" (Repeating) - Defines whether stop points needs to be repeated after the last one.
+func NewBackgroundRadialGradient(params Params) BackgroundElement {
+	result := new(backgroundRadialGradient)
+	result.init()
+	for tag, value := range params {
+		result.Set(tag, value)
+	}
+	return result
+}
+
+// NewCircleRadialGradient creates the new background circle radial gradient.
+func NewCircleRadialGradient[radiusType SizeUnit | RadialGradientRadiusType](xCenter, yCenter SizeUnit, radius radiusType, repeating bool, point1 GradientPoint, point2 GradientPoint, points ...GradientPoint) BackgroundElement {
+	params := Params{
+		RadialGradientShape:  CircleGradient,
+		Gradient:             append([]GradientPoint{point1, point2}, points...),
+		RadialGradientRadius: radius,
+	}
+	if xCenter.Type != Auto {
+		params[CenterX] = xCenter
+	}
+	if yCenter.Type != Auto {
+		params[CenterY] = yCenter
+	}
+	if repeating {
+		params[Repeating] = true
+	}
+	return NewBackgroundRadialGradient(params)
+}
+
+// NewEllipseRadialGradient creates the new background ellipse radial gradient.
+func NewEllipseRadialGradient[radiusType []SizeUnit | RadialGradientRadiusType](xCenter, yCenter SizeUnit, radius radiusType, repeating bool, point1 GradientPoint, point2 GradientPoint, points ...GradientPoint) BackgroundElement {
+	params := Params{
+		RadialGradientShape:  EllipseGradient,
+		Gradient:             append([]GradientPoint{point1, point2}, points...),
+		RadialGradientRadius: radius,
+	}
+	if xCenter.Type != Auto {
+		params[CenterX] = xCenter
+	}
+	if yCenter.Type != Auto {
+		params[CenterY] = yCenter
+	}
+	if repeating {
+		params[Repeating] = true
+	}
+	return NewBackgroundRadialGradient(params)
+}
+
+func (gradient *backgroundRadialGradient) init() {
+	gradient.backgroundElement.init()
+	gradient.normalize = normalizeRadialGradientTag
+	gradient.set = backgroundRadialGradientSet
+	gradient.supportedProperties = []PropertyName{
+		RadialGradientRadius, RadialGradientShape, CenterX, CenterY, Gradient, Repeating,
+	}
+}
+
+func (gradient *backgroundRadialGradient) Tag() string {
+	return "radial-gradient"
+}
+
+func (image *backgroundRadialGradient) Clone() BackgroundElement {
+	result := NewBackgroundRadialGradient(nil)
+	for tag, value := range image.properties {
+		result.setRaw(tag, value)
+	}
+	return result
+}
+
+func normalizeRadialGradientTag(tag PropertyName) PropertyName {
+	tag = defaultNormalize(tag)
+	switch tag {
+	case Radius:
+		tag = RadialGradientRadius
+
+	case Shape:
+		tag = RadialGradientShape
+
+	case "x-center":
+		tag = CenterX
+
+	case "y-center":
+		tag = CenterY
+	}
+
+	return tag
+}
+
+func backgroundRadialGradientSet(properties Properties, tag PropertyName, value any) []PropertyName {
+	switch tag {
+	case RadialGradientRadius:
+		switch value := value.(type) {
+		case []SizeUnit:
+			switch len(value) {
+			case 0:
+				properties.setRaw(RadialGradientRadius, nil)
+
+			case 1:
+				if value[0].Type == Auto {
+					properties.setRaw(RadialGradientRadius, nil)
+				} else {
+					properties.setRaw(RadialGradientRadius, value[0])
+				}
+
+			default:
+				properties.setRaw(RadialGradientRadius, value)
+			}
+			return []PropertyName{tag}
+
+		case []any:
+			switch len(value) {
+			case 0:
+				properties.setRaw(RadialGradientRadius, nil)
+				return []PropertyName{tag}
+
+			case 1:
+				return backgroundRadialGradientSet(properties, RadialGradientRadius, value[0])
+
+			default:
+				properties.setRaw(RadialGradientRadius, value)
+				return []PropertyName{tag}
+			}
+
+		case string:
+			if setSimpleProperty(properties, RadialGradientRadius, value) {
+				return []PropertyName{tag}
+			}
+			if size, err := stringToSizeUnit(value); err == nil {
+				if size.Type == Auto {
+					properties.setRaw(RadialGradientRadius, nil)
+				} else {
+					properties.setRaw(RadialGradientRadius, size)
+				}
+				return []PropertyName{tag}
+			}
+			return setEnumProperty(properties, RadialGradientRadius, value, enumProperties[RadialGradientRadius].values)
+
+		case SizeUnit:
+			if value.Type == Auto {
+				properties.setRaw(RadialGradientRadius, nil)
+			} else {
+				properties.setRaw(RadialGradientRadius, value)
+			}
+			return []PropertyName{tag}
+
+		case RadialGradientRadiusType:
+			return setEnumProperty(properties, RadialGradientRadius, int(value), enumProperties[RadialGradientRadius].values)
+
+		case int:
+			return setEnumProperty(properties, RadialGradientRadius, value, enumProperties[RadialGradientRadius].values)
+		}
+
+		ErrorLogF(`Invalid value of "%s" property: %v`, tag, value)
+		return nil
+
+	case RadialGradientShape, CenterX, CenterY:
+		return propertiesSet(properties, tag, value)
+	}
+
+	return backgroundGradientSet(properties, tag, value)
+}
+
+func (gradient *backgroundRadialGradient) cssStyle(session Session) string {
+	buffer := allocStringBuilder()
+	defer freeStringBuilder(buffer)
+
+	if repeating, _ := boolProperty(gradient, Repeating, session); repeating {
+		buffer.WriteString(`repeating-radial-gradient(`)
+	} else {
+		buffer.WriteString(`radial-gradient(`)
+	}
+
+	var shapeText string
+	if shape, ok := enumProperty(gradient, RadialGradientShape, session, EllipseGradient); ok && shape == CircleGradient {
+		shapeText = `circle `
+	} else {
+		shapeText = `ellipse `
+	}
+
+	if value, ok := gradient.properties[RadialGradientRadius]; ok {
+		switch value := value.(type) {
+		case string:
+			if text, ok := session.resolveConstants(value); ok {
+				values := enumProperties[RadialGradientRadius]
+				if n, ok := enumStringToInt(text, values.values, false); ok {
+					buffer.WriteString(shapeText)
+					shapeText = ""
+					buffer.WriteString(values.cssValues[n])
+					buffer.WriteString(" ")
+				} else {
+					if r, ok := StringToSizeUnit(text); ok && r.Type != Auto {
+						buffer.WriteString("ellipse ")
+						shapeText = ""
+						buffer.WriteString(r.cssString("", session))
+						buffer.WriteString(" ")
+						buffer.WriteString(r.cssString("", session))
+						buffer.WriteString(" ")
+					} else {
+						ErrorLog(`Invalid radial gradient radius: ` + text)
+					}
+				}
+			} else {
+				ErrorLog(`Invalid radial gradient radius: ` + value)
+			}
+
+		case int:
+			values := enumProperties[RadialGradientRadius].cssValues
+			if value >= 0 && value < len(values) {
+				buffer.WriteString(shapeText)
+				shapeText = ""
+				buffer.WriteString(values[value])
+				buffer.WriteString(" ")
+			} else {
+				ErrorLogF(`Invalid radial gradient radius: %d`, value)
+			}
+
+		case SizeUnit:
+			if value.Type != Auto {
+				buffer.WriteString("ellipse ")
+				shapeText = ""
+				buffer.WriteString(value.cssString("", session))
+				buffer.WriteString(" ")
+				buffer.WriteString(value.cssString("", session))
+				buffer.WriteString(" ")
+			}
+
+		case []SizeUnit:
+			count := len(value)
+			if count > 2 {
+				count = 2
+			}
+			buffer.WriteString("ellipse ")
+			shapeText = ""
+			for i := 0; i < count; i++ {
+				buffer.WriteString(value[i].cssString("50%", session))
+				buffer.WriteString(" ")
+			}
+
+		case []any:
+			count := len(value)
+			if count > 2 {
+				count = 2
+			}
+			buffer.WriteString("ellipse ")
+			shapeText = ""
+			for i := 0; i < count; i++ {
+				if value[i] != nil {
+					switch value := value[i].(type) {
+					case SizeUnit:
+						buffer.WriteString(value.cssString("50%", session))
+						buffer.WriteString(" ")
+
+					case string:
+						if text, ok := session.resolveConstants(value); ok {
+							if size, err := stringToSizeUnit(text); err == nil {
+								buffer.WriteString(size.cssString("50%", session))
+								buffer.WriteString(" ")
+							} else {
+								buffer.WriteString("50% ")
+							}
+						} else {
+							buffer.WriteString("50% ")
+						}
+					}
+				} else {
+					buffer.WriteString("50% ")
+				}
+			}
+		}
+	}
+
+	x, _ := sizeProperty(gradient, CenterX, session)
+	y, _ := sizeProperty(gradient, CenterX, session)
+	if x.Type != Auto || y.Type != Auto {
+		if shapeText != "" {
+			buffer.WriteString(shapeText)
+		}
+		buffer.WriteString("at ")
+		buffer.WriteString(x.cssString("50%", session))
+		buffer.WriteString(" ")
+		buffer.WriteString(y.cssString("50%", session))
+	} else if shapeText != "" {
+		buffer.WriteString(shapeText)
+	}
+
+	buffer.WriteString(", ")
+	if !gradient.writeGradient(session, buffer) {
+		return ""
+	}
+
+	buffer.WriteString(") ")
+
+	return buffer.String()
+}
+
+func (gradient *backgroundRadialGradient) writeString(buffer *strings.Builder, indent string) {
+	gradient.writeToBuffer(buffer, indent, gradient.Tag(), []PropertyName{
+		Gradient,
+		CenterX,
+		CenterY,
+		Repeating,
+		RadialGradientShape,
+		RadialGradientRadius,
+	})
+}
+
+func (gradient *backgroundRadialGradient) String() string {
+	return runStringWriter(gradient)
+}

border.go

@@ -5,44 +5,173 @@ import (
 	"strings"
 )
 
+// Constants related to view's border description
 const (
 	// NoneLine constant specifies that there is no border
 	NoneLine = 0
+
 	// SolidLine constant specifies the border/line as a solid line
 	SolidLine = 1
+
 	// DashedLine constant specifies the border/line as a dashed line
 	DashedLine = 2
+
 	// DottedLine constant specifies the border/line as a dotted line
 	DottedLine = 3
+
 	// DoubleLine constant specifies the border/line as a double solid line
 	DoubleLine = 4
+
 	// DoubleLine constant specifies the border/line as a double solid line
 	WavyLine = 5
 
 	// LeftStyle is the constant for "left-style" property tag.
-	LeftStyle = "left-style"
-	// RightStyle is the constant for "-right-style" property tag.
-	RightStyle = "right-style"
+	//
+	// Used by BorderProperty.
+	// Left border line style.
+	//
+	// Supported types: int, string.
+	//
+	// Values:
+	//  - 0 (NoneLine) or "none" - The border will not be drawn.
+	//  - 1 (SolidLine) or "solid" - Solid line as a border.
+	//  - 2 (DashedLine) or "dashed" - Dashed line as a border.
+	//  - 3 (DottedLine) or "dotted" - Dotted line as a border.
+	//  - 4 (DoubleLine) or "double" - Double line as a border.
+	LeftStyle PropertyName = "left-style"
+
+	// RightStyle is the constant for "right-style" property tag.
+	//
+	// Used by BorderProperty.
+	// Right border line style.
+	//
+	// Supported types: int, string.
+	//
+	// Values:
+	//  - 0 (NoneLine) or "none" - The border will not be drawn.
+	//  - 1 (SolidLine) or "solid" - Solid line as a border.
+	//  - 2 (DashedLine) or "dashed" - Dashed line as a border.
+	//  - 3 (DottedLine) or "dotted" - Dotted line as a border.
+	//  - 4 (DoubleLine) or "double" - Double line as a border.
+	RightStyle PropertyName = "right-style"
+
 	// TopStyle is the constant for "top-style" property tag.
-	TopStyle = "top-style"
+	//
+	// Used by BorderProperty.
+	// Top border line style.
+	//
+	// Supported types: int, string.
+	//
+	// Values:
+	//  - 0 (NoneLine) or "none" - The border will not be drawn.
+	//  - 1 (SolidLine) or "solid" - Solid line as a border.
+	//  - 2 (DashedLine) or "dashed" - Dashed line as a border.
+	//  - 3 (DottedLine) or "dotted" - Dotted line as a border.
+	//  - 4 (DoubleLine) or "double" - Double line as a border.
+	TopStyle PropertyName = "top-style"
+
 	// BottomStyle is the constant for "bottom-style" property tag.
-	BottomStyle = "bottom-style"
+	//
+	// Used by BorderProperty.
+	// Bottom border line style.
+	//
+	// Supported types: int, string.
+	//
+	// Values:
+	//  - 0 (NoneLine) or "none" - The border will not be drawn.
+	//  - 1 (SolidLine) or "solid" - Solid line as a border.
+	//  - 2 (DashedLine) or "dashed" - Dashed line as a border.
+	//  - 3 (DottedLine) or "dotted" - Dotted line as a border.
+	//  - 4 (DoubleLine) or "double" - Double line as a border.
+	BottomStyle PropertyName = "bottom-style"
+
 	// LeftWidth is the constant for "left-width" property tag.
-	LeftWidth = "left-width"
-	// RightWidth is the constant for "-right-width" property tag.
-	RightWidth = "right-width"
+	//
+	// Used by BorderProperty.
+	// Left border line width.
+	//
+	// Supported types: SizeUnit, SizeFunc, string, float, int.
+	//
+	// Internal type is SizeUnit, other types converted to it during assignment.
+	// See [SizeUnit] description for more details.
+	LeftWidth PropertyName = "left-width"
+
+	// RightWidth is the constant for "right-width" property tag.
+	//
+	// Used by BorderProperty.
+	// Right border line width.
+	//
+	// Supported types: SizeUnit, SizeFunc, string, float, int.
+	//
+	// Internal type is SizeUnit, other types converted to it during assignment.
+	// See [SizeUnit] description for more details.
+	RightWidth PropertyName = "right-width"
+
 	// TopWidth is the constant for "top-width" property tag.
-	TopWidth = "top-width"
+	//
+	// Used by BorderProperty.
+	// Top border line width.
+	//
+	// Supported types: SizeUnit, SizeFunc, string, float, int.
+	//
+	// Internal type is SizeUnit, other types converted to it during assignment.
+	// See [SizeUnit] description for more details.
+	TopWidth PropertyName = "top-width"
+
 	// BottomWidth is the constant for "bottom-width" property tag.
-	BottomWidth = "bottom-width"
+	//
+	// Used by BorderProperty.
+	// Bottom border line width.
+	//
+	// Supported types: SizeUnit, SizeFunc, string, float, int.
+	//
+	// Internal type is SizeUnit, other types converted to it during assignment.
+	// See [SizeUnit] description for more details.
+	BottomWidth PropertyName = "bottom-width"
+
 	// LeftColor is the constant for "left-color" property tag.
-	LeftColor = "left-color"
-	// RightColor is the constant for "-right-color" property tag.
-	RightColor = "right-color"
+	//
+	// Used by BorderProperty.
+	// Left border line color.
+	//
+	// Supported types: Color, string.
+	//
+	// Internal type is Color, other types converted to it during assignment.
+	// See [Color] description for more details.
+	LeftColor PropertyName = "left-color"
+
+	// RightColor is the constant for "right-color" property tag.
+	//
+	// Used by BorderProperty.
+	// Right border line color.
+	//
+	// Supported types: Color, string.
+	//
+	// Internal type is Color, other types converted to it during assignment.
+	// See [Color] description for more details.
+	RightColor PropertyName = "right-color"
+
 	// TopColor is the constant for "top-color" property tag.
-	TopColor = "top-color"
+	//
+	// Used by BorderProperty.
+	// Top border line color.
+	//
+	// Supported types: Color, string.
+	//
+	// Internal type is Color, other types converted to it during assignment.
+	// See [Color] description for more details.
+	TopColor PropertyName = "top-color"
+
 	// BottomColor is the constant for "bottom-color" property tag.
-	BottomColor = "bottom-color"
+	//
+	// Used by BorderProperty.
+	// Bottom border line color.
+	//
+	// Supported types: Color, string.
+	//
+	// Internal type is Color, other types converted to it during assignment.
+	// See [Color] description for more details.
+	BottomColor PropertyName = "bottom-color"
 )
 
 // BorderProperty is the interface of a view border data
@@ -50,8 +179,11 @@ type BorderProperty interface {
 	Properties
 	fmt.Stringer
 	stringWriter
+
+	// ViewBorders returns top, right, bottom and left borders information all together
 	ViewBorders(session Session) ViewBorders
-	delete(tag string)
+
+	deleteTag(tag PropertyName) bool
 	cssStyle(builder cssBuilder, session Session)
 	cssWidth(builder cssBuilder, session Session)
 	cssColor(builder cssBuilder, session Session)
@@ -61,12 +193,12 @@ type BorderProperty interface {
 }
 
 type borderProperty struct {
-	propertyList
+	dataProperty
 }
 
 func newBorderProperty(value any) BorderProperty {
 	border := new(borderProperty)
-	border.properties = map[string]any{}
+	border.init()
 
 	if value != nil {
 		switch value := value.(type) {
@@ -128,12 +260,20 @@ func newBorderProperty(value any) BorderProperty {
 	return border
 }
 
-// NewBorder creates the new BorderProperty
+// NewBorder creates the new BorderProperty.
+// The following properties can be used:
+//
+// "style" (Style). Determines the line style (int). Valid values: 0 (NoneLine), 1 (SolidLine), 2 (DashedLine), 3 (DottedLine), or 4 (DoubleLine);
+//
+// "color" (ColorTag). Determines the line color (Color);
+//
+// "width" (Width). Determines the line thickness (SizeUnit).
 func NewBorder(params Params) BorderProperty {
 	border := new(borderProperty)
-	border.properties = map[string]any{}
+	border.init()
+
 	if params != nil {
-		for _, tag := range []string{Style, Width, ColorTag, Left, Right, Top, Bottom,
+		for _, tag := range []PropertyName{Style, Width, ColorTag, Left, Right, Top, Bottom,
 			LeftStyle, RightStyle, TopStyle, BottomStyle,
 			LeftWidth, RightWidth, TopWidth, BottomWidth,
 			LeftColor, RightColor, TopColor, BottomColor} {
@@ -145,8 +285,37 @@ func NewBorder(params Params) BorderProperty {
 	return border
 }
 
-func (border *borderProperty) normalizeTag(tag string) string {
-	tag = strings.ToLower(tag)
+func (border *borderProperty) init() {
+	border.dataProperty.init()
+	border.normalize = normalizeBorderTag
+	border.get = borderGet
+	border.set = borderSet
+	border.remove = borderRemove
+	border.supportedProperties = []PropertyName{
+		Left,
+		Right,
+		Top,
+		Bottom,
+		Style,
+		LeftStyle,
+		RightStyle,
+		TopStyle,
+		BottomStyle,
+		Width,
+		LeftWidth,
+		RightWidth,
+		TopWidth,
+		BottomWidth,
+		ColorTag,
+		LeftColor,
+		RightColor,
+		TopColor,
+		BottomColor,
+	}
+}
+
+func normalizeBorderTag(tag PropertyName) PropertyName {
+	tag = defaultNormalize(tag)
 	switch tag {
 	case BorderLeft, CellBorderLeft:
 		return Left
@@ -213,23 +382,23 @@ func (border *borderProperty) writeString(buffer *strings.Builder, indent string
 	buffer.WriteString("_{ ")
 	comma := false
 
-	write := func(tag string, value any) {
+	write := func(tag PropertyName, value any) {
 		if comma {
 			buffer.WriteString(", ")
 		}
-		buffer.WriteString(tag)
+		buffer.WriteString(string(tag))
 		buffer.WriteString(" = ")
 		writePropertyValue(buffer, BorderStyle, value, indent)
 		comma = true
 	}
 
-	for _, tag := range []string{Style, Width, ColorTag} {
+	for _, tag := range []PropertyName{Style, Width, ColorTag} {
 		if value, ok := border.properties[tag]; ok {
 			write(tag, value)
 		}
 	}
 
-	for _, side := range []string{Top, Right, Bottom, Left} {
+	for _, side := range []PropertyName{Top, Right, Bottom, Left} {
 		style, okStyle := border.properties[side+"-"+Style]
 		width, okWidth := border.properties[side+"-"+Width]
 		color, okColor := border.properties[side+"-"+ColorTag]
@@ -239,7 +408,7 @@ func (border *borderProperty) writeString(buffer *strings.Builder, indent string
 				comma = false
 			}
 
-			buffer.WriteString(side)
+			buffer.WriteString(string(side))
 			buffer.WriteString(" = _{ ")
 			if okStyle {
 				write(Style, style)
@@ -262,164 +431,96 @@ func (border *borderProperty) String() string {
 	return runStringWriter(border)
 }
 
-func (border *borderProperty) setSingleBorderObject(prefix string, obj DataObject) bool {
-	result := true
-	if text, ok := obj.PropertyValue(Style); ok {
-		if !border.setEnumProperty(prefix+"-style", text, enumProperties[BorderStyle].values) {
-			result = false
-		}
-	}
-	if text, ok := obj.PropertyValue(ColorTag); ok {
-		if !border.setColorProperty(prefix+"-color", text) {
-			result = false
-		}
-	}
-	if text, ok := obj.PropertyValue("width"); ok {
-		if !border.setSizeProperty(prefix+"-width", text) {
-			result = false
-		}
-	}
-	return result
-}
-
 func (border *borderProperty) setBorderObject(obj DataObject) bool {
 	result := true
-
-	for _, side := range []string{Top, Right, Bottom, Left} {
-		if node := obj.PropertyByTag(side); node != nil {
-			if node.Type() == ObjectNode {
-				if !border.setSingleBorderObject(side, node.Object()) {
+	for i := 0; i < obj.PropertyCount(); i++ {
+		if node := obj.Property(i); node != nil {
+			tag := PropertyName(node.Tag())
+			switch node.Type() {
+			case TextNode:
+				if borderSet(border, tag, node.Text()) == nil {
 					result = false
 				}
-			} else {
-				notCompatibleType(side, node)
-				result = false
-			}
-		}
-	}
 
-	if text, ok := obj.PropertyValue(Style); ok {
-		values := split4Values(text)
-		styles := enumProperties[BorderStyle].values
-		switch len(values) {
-		case 1:
-			if !border.setEnumProperty(Style, values[0], styles) {
-				result = false
-			}
-
-		case 4:
-			for n, tag := range [4]string{TopStyle, RightStyle, BottomStyle, LeftStyle} {
-				if !border.setEnumProperty(tag, values[n], styles) {
+			case ObjectNode:
+				if borderSet(border, tag, node.Object()) == nil {
 					result = false
 				}
-			}
 
-		default:
-			notCompatibleType(Style, text)
+			default:
+				result = false
+			}
+		} else {
 			result = false
 		}
 	}
-
-	if text, ok := obj.PropertyValue(ColorTag); ok {
-		values := split4Values(text)
-		switch len(values) {
-		case 1:
-			if !border.setColorProperty(ColorTag, values[0]) {
-				return false
-			}
-
-		case 4:
-			for n, tag := range [4]string{TopColor, RightColor, BottomColor, LeftColor} {
-				if !border.setColorProperty(tag, values[n]) {
-					return false
-				}
-			}
-
-		default:
-			notCompatibleType(ColorTag, text)
-			result = false
-		}
-	}
-
-	if text, ok := obj.PropertyValue(Width); ok {
-		values := split4Values(text)
-		switch len(values) {
-		case 1:
-			if !border.setSizeProperty(Width, values[0]) {
-				result = false
-			}
-
-		case 4:
-			for n, tag := range [4]string{TopWidth, RightWidth, BottomWidth, LeftWidth} {
-				if !border.setSizeProperty(tag, values[n]) {
-					result = false
-				}
-			}
-
-		default:
-			notCompatibleType(Width, text)
-			result = false
-		}
-	}
-
 	return result
 }
 
-func (border *borderProperty) Remove(tag string) {
-	tag = border.normalizeTag(tag)
+func borderRemove(properties Properties, tag PropertyName) []PropertyName {
+	result := []PropertyName{}
+	removeTag := func(t PropertyName) {
+		if properties.getRaw(t) != nil {
+			properties.setRaw(t, nil)
+			result = append(result, t)
+		}
+	}
 
 	switch tag {
 	case Style:
-		for _, t := range []string{tag, TopStyle, RightStyle, BottomStyle, LeftStyle} {
-			delete(border.properties, t)
+		for _, t := range []PropertyName{tag, TopStyle, RightStyle, BottomStyle, LeftStyle} {
+			removeTag(t)
 		}
 
 	case Width:
-		for _, t := range []string{tag, TopWidth, RightWidth, BottomWidth, LeftWidth} {
-			delete(border.properties, t)
+		for _, t := range []PropertyName{tag, TopWidth, RightWidth, BottomWidth, LeftWidth} {
+			removeTag(t)
 		}
 
 	case ColorTag:
-		for _, t := range []string{tag, TopColor, RightColor, BottomColor, LeftColor} {
-			delete(border.properties, t)
+		for _, t := range []PropertyName{tag, TopColor, RightColor, BottomColor, LeftColor} {
+			removeTag(t)
 		}
 
 	case Left, Right, Top, Bottom:
-		border.Remove(tag + "-style")
-		border.Remove(tag + "-width")
-		border.Remove(tag + "-color")
+		removeTag(tag + "-style")
+		removeTag(tag + "-width")
+		removeTag(tag + "-color")
 
 	case LeftStyle, RightStyle, TopStyle, BottomStyle:
-		delete(border.properties, tag)
-		if style, ok := border.properties[Style]; ok && style != nil {
-			for _, t := range []string{TopStyle, RightStyle, BottomStyle, LeftStyle} {
+		removeTag(tag)
+		if style := properties.getRaw(Style); style != nil {
+			for _, t := range []PropertyName{TopStyle, RightStyle, BottomStyle, LeftStyle} {
 				if t != tag {
-					if _, ok := border.properties[t]; !ok {
-						border.properties[t] = style
+					if properties.getRaw(t) == nil {
+						properties.setRaw(t, style)
+						result = append(result, t)
 					}
 				}
 			}
 		}
 
 	case LeftWidth, RightWidth, TopWidth, BottomWidth:
-		delete(border.properties, tag)
-		if width, ok := border.properties[Width]; ok && width != nil {
-			for _, t := range []string{TopWidth, RightWidth, BottomWidth, LeftWidth} {
+		removeTag(tag)
+		if width := properties.getRaw(Width); width != nil {
+			for _, t := range []PropertyName{TopWidth, RightWidth, BottomWidth, LeftWidth} {
 				if t != tag {
-					if _, ok := border.properties[t]; !ok {
-						border.properties[t] = width
+					if properties.getRaw(t) == nil {
+						properties.setRaw(t, width)
+						result = append(result, t)
 					}
 				}
 			}
 		}
 
 	case LeftColor, RightColor, TopColor, BottomColor:
-		delete(border.properties, tag)
-		if color, ok := border.properties[ColorTag]; ok && color != nil {
-			for _, t := range []string{TopColor, RightColor, BottomColor, LeftColor} {
+		removeTag(tag)
+		if color := properties.getRaw(ColorTag); color != nil {
+			for _, t := range []PropertyName{TopColor, RightColor, BottomColor, LeftColor} {
 				if t != tag {
-					if _, ok := border.properties[t]; !ok {
-						border.properties[t] = color
+					if properties.getRaw(t) == nil {
+						properties.setRaw(t, color)
+						result = append(result, t)
 					}
 				}
 			}
@@ -428,80 +529,118 @@ func (border *borderProperty) Remove(tag string) {
 	default:
 		ErrorLogF(`"%s" property is not compatible with the BorderProperty`, tag)
 	}
+
+	return result
 }
 
-func (border *borderProperty) Set(tag string, value any) bool {
-	if value == nil {
-		border.Remove(tag)
-		return true
-	}
+func borderSet(properties Properties, tag PropertyName, value any) []PropertyName {
 
-	tag = border.normalizeTag(tag)
+	setSingleBorderObject := func(prefix PropertyName, obj DataObject) []PropertyName {
+		result := []PropertyName{}
+		if text, ok := obj.PropertyValue(string(Style)); ok {
+			props := setEnumProperty(properties, prefix+"-style", text, enumProperties[BorderStyle].values)
+			if props == nil {
+				return nil
+			}
+			result = append(result, props...)
+		}
+		if text, ok := obj.PropertyValue(string(ColorTag)); ok {
+			props := setColorProperty(properties, prefix+"-color", text)
+			if props == nil && len(result) == 0 {
+				return nil
+			}
+			result = append(result, props...)
+		}
+		if text, ok := obj.PropertyValue("width"); ok {
+			props := setSizeProperty(properties, prefix+"-width", text)
+			if props == nil && len(result) == 0 {
+				return nil
+			}
+			result = append(result, props...)
+		}
+		if len(result) > 0 {
+			result = append(result, prefix)
+		}
+		return result
+	}
 
 	switch tag {
 	case Style:
-		if border.setEnumProperty(Style, value, enumProperties[BorderStyle].values) {
-			for _, side := range []string{TopStyle, RightStyle, BottomStyle, LeftStyle} {
-				delete(border.properties, side)
+		if result := setEnumProperty(properties, Style, value, enumProperties[BorderStyle].values); result != nil {
+			for _, side := range []PropertyName{TopStyle, RightStyle, BottomStyle, LeftStyle} {
+				if value := properties.getRaw(side); value != nil {
+					properties.setRaw(side, nil)
+					result = append(result, side)
+				}
 			}
-			return true
+			return result
 		}
 
 	case Width:
-		if border.setSizeProperty(Width, value) {
-			for _, side := range []string{TopWidth, RightWidth, BottomWidth, LeftWidth} {
-				delete(border.properties, side)
+		if result := setSizeProperty(properties, Width, value); result != nil {
+			for _, side := range []PropertyName{TopWidth, RightWidth, BottomWidth, LeftWidth} {
+				if value := properties.getRaw(side); value != nil {
+					properties.setRaw(side, nil)
+					result = append(result, side)
+				}
 			}
-			return true
+			return result
 		}
 
 	case ColorTag:
-		if border.setColorProperty(ColorTag, value) {
-			for _, side := range []string{TopColor, RightColor, BottomColor, LeftColor} {
-				delete(border.properties, side)
+		if result := setColorProperty(properties, ColorTag, value); result != nil {
+			for _, side := range []PropertyName{TopColor, RightColor, BottomColor, LeftColor} {
+				if value := properties.getRaw(side); value != nil {
+					properties.setRaw(side, nil)
+					result = append(result, side)
+				}
 			}
-			return true
+			return result
 		}
 
 	case LeftStyle, RightStyle, TopStyle, BottomStyle:
-		return border.setEnumProperty(tag, value, enumProperties[BorderStyle].values)
+		return setEnumProperty(properties, tag, value, enumProperties[BorderStyle].values)
 
 	case LeftWidth, RightWidth, TopWidth, BottomWidth:
-		return border.setSizeProperty(tag, value)
+		return setSizeProperty(properties, tag, value)
 
 	case LeftColor, RightColor, TopColor, BottomColor:
-		return border.setColorProperty(tag, value)
+		return setColorProperty(properties, tag, value)
 
 	case Left, Right, Top, Bottom:
 		switch value := value.(type) {
 		case string:
 			if obj := ParseDataText(value); obj != nil {
-				return border.setSingleBorderObject(tag, obj)
+				return setSingleBorderObject(tag, obj)
 			}
 
 		case DataObject:
-			return border.setSingleBorderObject(tag, value)
+			return setSingleBorderObject(tag, value)
 
 		case BorderProperty:
+			result := []PropertyName{}
 			styleTag := tag + "-" + Style
 			if style := value.Get(styleTag); value != nil {
-				border.properties[styleTag] = style
+				properties.setRaw(styleTag, style)
+				result = append(result, styleTag)
 			}
 			colorTag := tag + "-" + ColorTag
 			if color := value.Get(colorTag); value != nil {
-				border.properties[colorTag] = color
+				properties.setRaw(colorTag, color)
+				result = append(result, colorTag)
 			}
 			widthTag := tag + "-" + Width
 			if width := value.Get(widthTag); value != nil {
-				border.properties[widthTag] = width
+				properties.setRaw(widthTag, width)
+				result = append(result, widthTag)
 			}
-			return true
+			return result
 
 		case ViewBorder:
-			border.properties[tag+"-"+Style] = value.Style
-			border.properties[tag+"-"+Width] = value.Width
-			border.properties[tag+"-"+ColorTag] = value.Color
-			return true
+			properties.setRaw(tag+"-"+Style, value.Style)
+			properties.setRaw(tag+"-"+Width, value.Width)
+			properties.setRaw(tag+"-"+ColorTag, value.Color)
+			return []PropertyName{tag + "-" + Style, tag + "-" + Width, tag + "-" + ColorTag}
 		}
 		fallthrough
 
@@ -509,105 +648,119 @@ func (border *borderProperty) Set(tag string, value any) bool {
 		ErrorLogF(`"%s" property is not compatible with the BorderProperty`, tag)
 	}
 
-	return false
+	return nil
 }
 
-func (border *borderProperty) Get(tag string) any {
-	tag = border.normalizeTag(tag)
-
-	if result, ok := border.properties[tag]; ok {
+func borderGet(properties Properties, tag PropertyName) any {
+	if result := properties.getRaw(tag); result != nil {
 		return result
 	}
 
 	switch tag {
 	case Left, Right, Top, Bottom:
 		result := newBorderProperty(nil)
-		if style, ok := border.properties[tag+"-"+Style]; ok {
+		if style := properties.getRaw(tag + "-" + Style); style != nil {
 			result.Set(Style, style)
-		} else if style, ok := border.properties[Style]; ok {
+		} else if style := properties.getRaw(Style); style != nil {
 			result.Set(Style, style)
 		}
-		if width, ok := border.properties[tag+"-"+Width]; ok {
+		if width := properties.getRaw(tag + "-" + Width); width != nil {
 			result.Set(Width, width)
-		} else if width, ok := border.properties[Width]; ok {
+		} else if width := properties.getRaw(Width); width != nil {
 			result.Set(Width, width)
 		}
-		if color, ok := border.properties[tag+"-"+ColorTag]; ok {
+		if color := properties.getRaw(tag + "-" + ColorTag); color != nil {
 			result.Set(ColorTag, color)
-		} else if color, ok := border.properties[ColorTag]; ok {
+		} else if color := properties.getRaw(ColorTag); color != nil {
 			result.Set(ColorTag, color)
 		}
 		return result
 
 	case LeftStyle, RightStyle, TopStyle, BottomStyle:
-		if style, ok := border.properties[tag]; ok {
+		if style := properties.getRaw(tag); style != nil {
 			return style
 		}
-		return border.properties[Style]
+		return properties.getRaw(Style)
 
 	case LeftWidth, RightWidth, TopWidth, BottomWidth:
-		if width, ok := border.properties[tag]; ok {
+		if width := properties.getRaw(tag); width != nil {
 			return width
 		}
-		return border.properties[Width]
+		return properties.getRaw(Width)
 
 	case LeftColor, RightColor, TopColor, BottomColor:
-		if color, ok := border.properties[tag]; ok {
+		if color := properties.getRaw(tag); color != nil {
 			return color
 		}
-		return border.properties[ColorTag]
+		return properties.getRaw(ColorTag)
 	}
 
 	return nil
 }
 
-func (border *borderProperty) delete(tag string) {
-	tag = border.normalizeTag(tag)
-	remove := []string{}
+func (border *borderProperty) deleteTag(tag PropertyName) bool {
+
+	result := false
+	removeTags := func(tags []PropertyName) {
+		for _, tag := range tags {
+			if border.getRaw(tag) != nil {
+				border.setRaw(tag, nil)
+				result = true
+			}
+		}
+	}
 
 	switch tag {
 	case Style:
-		remove = []string{Style, LeftStyle, RightStyle, TopStyle, BottomStyle}
+		removeTags([]PropertyName{Style, LeftStyle, RightStyle, TopStyle, BottomStyle})
 
 	case Width:
-		remove = []string{Width, LeftWidth, RightWidth, TopWidth, BottomWidth}
+		removeTags([]PropertyName{Width, LeftWidth, RightWidth, TopWidth, BottomWidth})
 
 	case ColorTag:
-		remove = []string{ColorTag, LeftColor, RightColor, TopColor, BottomColor}
+		removeTags([]PropertyName{ColorTag, LeftColor, RightColor, TopColor, BottomColor})
 
 	case Left, Right, Top, Bottom:
 		if border.Get(Style) != nil {
 			border.properties[tag+"-"+Style] = 0
-			remove = []string{tag + "-" + ColorTag, tag + "-" + Width}
+			result = true
+			removeTags([]PropertyName{tag + "-" + ColorTag, tag + "-" + Width})
 		} else {
-			remove = []string{tag + "-" + Style, tag + "-" + ColorTag, tag + "-" + Width}
+			removeTags([]PropertyName{tag + "-" + Style, tag + "-" + ColorTag, tag + "-" + Width})
 		}
 
 	case LeftStyle, RightStyle, TopStyle, BottomStyle:
-		if border.Get(Style) != nil {
-			border.properties[tag] = 0
-		} else {
-			remove = []string{tag}
+		if border.getRaw(tag) != nil {
+			if border.Get(Style) != nil {
+				border.properties[tag] = 0
+				result = true
+			} else {
+				removeTags([]PropertyName{tag})
+			}
 		}
 
 	case LeftWidth, RightWidth, TopWidth, BottomWidth:
-		if border.Get(Width) != nil {
-			border.properties[tag] = AutoSize()
-		} else {
-			remove = []string{tag}
+		if border.getRaw(tag) != nil {
+			if border.Get(Width) != nil {
+				border.properties[tag] = AutoSize()
+				result = true
+			} else {
+				removeTags([]PropertyName{tag})
+			}
 		}
 
 	case LeftColor, RightColor, TopColor, BottomColor:
-		if border.Get(ColorTag) != nil {
-			border.properties[tag] = 0
-		} else {
-			remove = []string{tag}
+		if border.getRaw(tag) != nil {
+			if border.Get(ColorTag) != nil {
+				border.properties[tag] = 0
+				result = true
+			} else {
+				removeTags([]PropertyName{tag})
+			}
 		}
 	}
 
-	for _, tag := range remove {
-		delete(border.properties, tag)
-	}
+	return result
 }
 
 func (border *borderProperty) ViewBorders(session Session) ViewBorders {
@@ -616,7 +769,7 @@ func (border *borderProperty) ViewBorders(session Session) ViewBorders {
 	defWidth, _ := sizeProperty(border, Width, session)
 	defColor, _ := colorProperty(border, ColorTag, session)
 
-	getBorder := func(prefix string) ViewBorder {
+	getBorder := func(prefix PropertyName) ViewBorder {
 		var result ViewBorder
 		var ok bool
 		if result.Style, ok = valueToEnum(border.getRaw(prefix+Style), BorderStyle, session, NoneLine); !ok {
@@ -645,9 +798,9 @@ func (border *borderProperty) cssStyle(builder cssBuilder, session Session) {
 	if borders.Top.Style == borders.Right.Style &&
 		borders.Top.Style == borders.Left.Style &&
 		borders.Top.Style == borders.Bottom.Style {
-		builder.add(BorderStyle, values[borders.Top.Style])
+		builder.add(string(BorderStyle), values[borders.Top.Style])
 	} else {
-		builder.addValues(BorderStyle, " ", values[borders.Top.Style],
+		builder.addValues(string(BorderStyle), " ", values[borders.Top.Style],
 			values[borders.Right.Style], values[borders.Bottom.Style], values[borders.Left.Style])
 	}
 }
@@ -703,8 +856,13 @@ func (border *borderProperty) cssColorValue(session Session) string {
 
 // ViewBorder describes parameters of a view border
 type ViewBorder struct {
+	// Style of the border line
 	Style int
+
+	// Color of the border line
 	Color Color
+
+	// Width of the border line
 	Width SizeUnit
 }
 
@@ -726,11 +884,25 @@ func (border *ViewBorders) AllTheSame() bool {
 		border.Top.Width.Equal(border.Bottom.Width)
 }
 
-func getBorder(style Properties, tag string) BorderProperty {
-	if value := style.Get(tag); value != nil {
+func getBorderProperty(properties Properties, tag PropertyName) BorderProperty {
+	if value := properties.getRaw(tag); value != nil {
 		if border, ok := value.(BorderProperty); ok {
 			return border
 		}
 	}
 	return nil
 }
+
+func setBorderPropertyElement(properties Properties, mainTag, tag PropertyName, value any) []PropertyName {
+	border := getBorderProperty(properties, mainTag)
+	if border == nil {
+		border = NewBorder(nil)
+		if border.Set(tag, value) {
+			properties.setRaw(mainTag, border)
+			return []PropertyName{mainTag, tag}
+		}
+	} else if border.Set(tag, value) {
+		return []PropertyName{mainTag, tag}
+	}
+	return nil
+}

bounds.go

@@ -5,34 +5,60 @@ import (
 	"strings"
 )
 
-// BorderProperty is the interface of a bounds property data
+// BorderProperty is an interface of a bounds property data
 type BoundsProperty interface {
 	Properties
 	fmt.Stringer
 	stringWriter
+
+	// Bounds returns top, right, bottom and left size of the bounds
 	Bounds(session Session) Bounds
 }
 
 type boundsPropertyData struct {
-	propertyList
+	dataProperty
 }
 
-// NewBoundsProperty creates the new BoundsProperty object
+// NewBoundsProperty creates the new BoundsProperty object.
+//
+// The following SizeUnit properties can be used: "left" (Left), "right" (Right), "top" (Top), and "bottom" (Bottom).
 func NewBoundsProperty(params Params) BoundsProperty {
 	bounds := new(boundsPropertyData)
-	bounds.properties = map[string]any{}
+	bounds.init()
+
 	if params != nil {
-		for _, tag := range []string{Top, Right, Bottom, Left} {
-			if value, ok := params[tag]; ok {
-				bounds.Set(tag, value)
+		for _, tag := range bounds.supportedProperties {
+			if value, ok := params[tag]; ok && value != nil {
+				bounds.set(bounds, tag, value)
 			}
 		}
 	}
 	return bounds
 }
 
-func (bounds *boundsPropertyData) normalizeTag(tag string) string {
-	tag = strings.ToLower(tag)
+// NewBounds creates the new BoundsProperty object.
+//
+// The arguments specify the boundaries in a clockwise direction: "top", "right", "bottom", and "left".
+//
+// If the argument is specified as int or float64, the value is considered to be in pixels.
+func NewBounds[topType SizeUnit | int | float64, rightType SizeUnit | int | float64, bottomType SizeUnit | int | float64, leftType SizeUnit | int | float64](
+	top topType, right rightType, bottom bottomType, left leftType) BoundsProperty {
+	return NewBoundsProperty(Params{
+		Top:    top,
+		Right:  right,
+		Bottom: bottom,
+		Left:   left,
+	})
+}
+
+func (bounds *boundsPropertyData) init() {
+	bounds.dataProperty.init()
+	bounds.normalize = normalizeBoundsTag
+	bounds.supportedProperties = []PropertyName{Top, Right, Bottom, Left}
+}
+
+func normalizeBoundsTag(tag PropertyName) PropertyName {
+	tag = defaultNormalize(tag)
 	switch tag {
 	case MarginTop, PaddingTop, CellPaddingTop,
 		"top-margin", "top-padding", "top-cell-padding":
@@ -61,12 +87,12 @@ func (bounds *boundsPropertyData) String() string {
 func (bounds *boundsPropertyData) writeString(buffer *strings.Builder, indent string) {
 	buffer.WriteString("_{ ")
 	comma := false
-	for _, tag := range []string{Top, Right, Bottom, Left} {
+	for _, tag := range []PropertyName{Top, Right, Bottom, Left} {
 		if value, ok := bounds.properties[tag]; ok {
 			if comma {
 				buffer.WriteString(", ")
 			}
-			buffer.WriteString(tag)
+			buffer.WriteString(string(tag))
 			buffer.WriteString(" = ")
 			writePropertyValue(buffer, tag, value, indent)
 			comma = true
@@ -75,38 +101,6 @@ func (bounds *boundsPropertyData) writeString(buffer *strings.Builder, indent st
 	buffer.WriteString(" }")
 }
 
-func (bounds *boundsPropertyData) Remove(tag string) {
-	bounds.propertyList.Remove(bounds.normalizeTag(tag))
-}
-
-func (bounds *boundsPropertyData) Set(tag string, value any) bool {
-	if value == nil {
-		bounds.Remove(tag)
-		return true
-	}
-
-	tag = bounds.normalizeTag(tag)
-
-	switch tag {
-	case Top, Right, Bottom, Left:
-		return bounds.setSizeProperty(tag, value)
-
-	default:
-		ErrorLogF(`"%s" property is not compatible with the BoundsProperty`, tag)
-	}
-
-	return false
-}
-
-func (bounds *boundsPropertyData) Get(tag string) any {
-	tag = bounds.normalizeTag(tag)
-	if value, ok := bounds.properties[tag]; ok {
-		return value
-	}
-
-	return nil
-}
-
 func (bounds *boundsPropertyData) Bounds(session Session) Bounds {
 	top, _ := sizeProperty(bounds, Top, session)
 	right, _ := sizeProperty(bounds, Right, session)
@@ -138,7 +132,7 @@ func (bounds *Bounds) SetAll(value SizeUnit) {
 	bounds.Left = value
 }
 
-func (bounds *Bounds) setFromProperties(tag, topTag, rightTag, bottomTag, leftTag string, properties Properties, session Session) {
+func (bounds *Bounds) setFromProperties(tag, topTag, rightTag, bottomTag, leftTag PropertyName, properties Properties, session Session) {
 	bounds.Top = AutoSize()
 	if size, ok := sizeProperty(properties, tag, session); ok {
 		bounds.Top = size
@@ -161,22 +155,6 @@ func (bounds *Bounds) setFromProperties(tag, topTag, rightTag, bottomTag, leftTa
 	}
 }
 
-/*
-func (bounds *Bounds) allFieldsAuto() bool {
-	return bounds.Left.Type == Auto &&
-		bounds.Top.Type == Auto &&
-		bounds.Right.Type == Auto &&
-		bounds.Bottom.Type == Auto
-}
-
-func (bounds *Bounds) allFieldsZero() bool {
-	return (bounds.Left.Type == Auto || bounds.Left.Value == 0) &&
-		(bounds.Top.Type == Auto || bounds.Top.Value == 0) &&
-		(bounds.Right.Type == Auto || bounds.Right.Value == 0) &&
-		(bounds.Bottom.Type == Auto || bounds.Bottom.Value == 0)
-}
-*/
-
 func (bounds *Bounds) allFieldsEqual() bool {
 	if bounds.Left.Type == bounds.Top.Type &&
 		bounds.Left.Type == bounds.Right.Type &&
@@ -190,20 +168,6 @@ func (bounds *Bounds) allFieldsEqual() bool {
 	return false
 }
 
-/*
-func (bounds Bounds) writeCSSString(buffer *strings.Builder, textForAuto string) {
-	buffer.WriteString(bounds.Top.cssString(textForAuto))
-	if !bounds.allFieldsEqual() {
-		buffer.WriteRune(' ')
-		buffer.WriteString(bounds.Right.cssString(textForAuto))
-		buffer.WriteRune(' ')
-		buffer.WriteString(bounds.Bottom.cssString(textForAuto))
-		buffer.WriteRune(' ')
-		buffer.WriteString(bounds.Left.cssString(textForAuto))
-	}
-}
-*/
-
 // String convert Bounds to string
 func (bounds *Bounds) String() string {
 	if bounds.allFieldsEqual() {
@@ -213,11 +177,11 @@ func (bounds *Bounds) String() string {
 		bounds.Bottom.String() + "," + bounds.Left.String()
 }
 
-func (bounds *Bounds) cssValue(tag string, builder cssBuilder, session Session) {
+func (bounds *Bounds) cssValue(tag PropertyName, builder cssBuilder, session Session) {
 	if bounds.allFieldsEqual() {
-		builder.add(tag, bounds.Top.cssString("0", session))
+		builder.add(string(tag), bounds.Top.cssString("0", session))
 	} else {
-		builder.addValues(tag, " ",
+		builder.addValues(string(tag), " ",
 			bounds.Top.cssString("0", session),
 			bounds.Right.cssString("0", session),
 			bounds.Bottom.cssString("0", session),
@@ -231,8 +195,8 @@ func (bounds *Bounds) cssString(session Session) string {
 	return builder.finish()
 }
 
-func (properties *propertyList) setBounds(tag string, value any) bool {
-	if !properties.setSimpleProperty(tag, value) {
+func setBoundsProperty(properties Properties, tag PropertyName, value any) []PropertyName {
+	if !setSimpleProperty(properties, tag, value) {
 		switch value := value.(type) {
 		case string:
 			if strings.Contains(value, ",") {
@@ -244,88 +208,119 @@ func (properties *propertyList) setBounds(tag string, value any) bool {
 
 				case 4:
 					bounds := NewBoundsProperty(nil)
-					for i, tag := range []string{Top, Right, Bottom, Left} {
+					for i, tag := range []PropertyName{Top, Right, Bottom, Left} {
 						if !bounds.Set(tag, values[i]) {
-							notCompatibleType(tag, value)
-							return false
+							return nil
 						}
 					}
-					properties.properties[tag] = bounds
-					return true
+					properties.setRaw(tag, bounds)
+					return []PropertyName{tag}
 
 				default:
 					notCompatibleType(tag, value)
-					return false
+					return nil
 				}
 			}
-			return properties.setSizeProperty(tag, value)
+			return setSizeProperty(properties, tag, value)
 
 		case SizeUnit:
-			properties.properties[tag] = value
+			properties.setRaw(tag, value)
 
 		case float32:
-			properties.properties[tag] = Px(float64(value))
+			properties.setRaw(tag, Px(float64(value)))
 
 		case float64:
-			properties.properties[tag] = Px(value)
+			properties.setRaw(tag, Px(value))
 
 		case Bounds:
 			bounds := NewBoundsProperty(nil)
 			if value.Top.Type != Auto {
-				bounds.Set(Top, value.Top)
+				bounds.setRaw(Top, value.Top)
 			}
 			if value.Right.Type != Auto {
-				bounds.Set(Right, value.Right)
+				bounds.setRaw(Right, value.Right)
 			}
 			if value.Bottom.Type != Auto {
-				bounds.Set(Bottom, value.Bottom)
+				bounds.setRaw(Bottom, value.Bottom)
 			}
 			if value.Left.Type != Auto {
-				bounds.Set(Left, value.Left)
+				bounds.setRaw(Left, value.Left)
 			}
-			properties.properties[tag] = bounds
+			properties.setRaw(tag, bounds)
 
 		case BoundsProperty:
-			properties.properties[tag] = value
+			properties.setRaw(tag, value)
 
 		case DataObject:
 			bounds := NewBoundsProperty(nil)
-			for _, tag := range []string{Top, Right, Bottom, Left} {
-				if text, ok := value.PropertyValue(tag); ok {
+			for _, tag := range []PropertyName{Top, Right, Bottom, Left} {
+				if text, ok := value.PropertyValue(string(tag)); ok {
 					if !bounds.Set(tag, text) {
 						notCompatibleType(tag, value)
-						return false
+						return nil
 					}
 				}
 			}
-			properties.properties[tag] = bounds
+			properties.setRaw(tag, bounds)
 
 		default:
 			if n, ok := isInt(value); ok {
-				properties.properties[tag] = Px(float64(n))
+				properties.setRaw(tag, Px(float64(n)))
 			} else {
 				notCompatibleType(tag, value)
-				return false
+				return nil
 			}
 		}
 	}
 
-	return true
+	return []PropertyName{tag}
 }
 
-func (properties *propertyList) boundsProperty(tag string) BoundsProperty {
-	if value, ok := properties.properties[tag]; ok {
+func removeBoundsPropertySide(properties Properties, mainTag, sideTag PropertyName) []PropertyName {
+	if bounds := getBoundsProperty(properties, mainTag); bounds != nil {
+		if bounds.getRaw(sideTag) != nil {
+			bounds.Remove(sideTag)
+			if bounds.empty() {
+				bounds = nil
+			}
+			properties.setRaw(mainTag, bounds)
+			return []PropertyName{mainTag, sideTag}
+		}
+	}
+	return []PropertyName{}
+}
+
+func setBoundsPropertySide(properties Properties, mainTag, sideTag PropertyName, value any) []PropertyName {
+	if value == nil {
+		return removeBoundsPropertySide(properties, mainTag, sideTag)
+	}
+
+	bounds := getBoundsProperty(properties, mainTag)
+	if bounds == nil {
+		bounds = NewBoundsProperty(nil)
+	}
+	if bounds.Set(sideTag, value) {
+		properties.setRaw(mainTag, bounds)
+		return []PropertyName{mainTag, sideTag}
+	}
+
+	notCompatibleType(sideTag, value)
+	return nil
+}
+
+func getBoundsProperty(properties Properties, tag PropertyName) BoundsProperty {
+	if value := properties.getRaw(tag); value != nil {
 		switch value := value.(type) {
 		case string:
 			bounds := NewBoundsProperty(nil)
-			for _, t := range []string{Top, Right, Bottom, Left} {
+			for _, t := range []PropertyName{Top, Right, Bottom, Left} {
 				bounds.Set(t, value)
 			}
 			return bounds
 
 		case SizeUnit:
 			bounds := NewBoundsProperty(nil)
-			for _, t := range []string{Top, Right, Bottom, Left} {
+			for _, t := range []PropertyName{Top, Right, Bottom, Left} {
 				bounds.Set(t, value)
 			}
 			return bounds
@@ -342,29 +337,10 @@ func (properties *propertyList) boundsProperty(tag string) BoundsProperty {
 		}
 	}
 
-	return NewBoundsProperty(nil)
+	return nil
 }
 
-func (properties *propertyList) removeBoundsSide(mainTag, sideTag string) {
-	bounds := properties.boundsProperty(mainTag)
-	if bounds.Get(sideTag) != nil {
-		bounds.Remove(sideTag)
-		properties.properties[mainTag] = bounds
-	}
-}
-
-func (properties *propertyList) setBoundsSide(mainTag, sideTag string, value any) bool {
-	bounds := properties.boundsProperty(mainTag)
-	if bounds.Set(sideTag, value) {
-		properties.properties[mainTag] = bounds
-		return true
-	}
-
-	notCompatibleType(sideTag, value)
-	return false
-}
-
-func boundsProperty(properties Properties, tag string, session Session) (Bounds, bool) {
+func getBounds(properties Properties, tag PropertyName, session Session) (Bounds, bool) {
 	if value := properties.Get(tag); value != nil {
 		switch value := value.(type) {
 		case string:

button.go

@@ -1,6 +1,6 @@
 package rui
 
-// Button - button view
+// Button represent a Button view
 type Button interface {
 	CustomView
 }
@@ -18,6 +18,7 @@ func NewButton(session Session, params Params) Button {
 
 func newButton(session Session) View {
 	return NewButton(session, nil)
+	//return new(buttonData)
 }
 
 func (button *buttonData) CreateSuperView(session Session) View {

canvas.go

@@ -6,38 +6,54 @@ import (
 	"strings"
 )
 
+// LineJoin is the type for setting the shape used to join two line segments where they meet.
+type LineJoin int
+
+// LineCap is the type for setting the shape used to draw the end points of lines.
+type LineCap int
+
+// Constants related to canvas view operations
 const (
 	// MiterJoin - Connected segments are joined by extending their outside edges
 	// to connect at a single point, with the effect of filling an additional
 	// lozenge-shaped area. This setting is affected by the miterLimit property
-	MiterJoin = 0
+	MiterJoin LineJoin = 0
+
 	// RoundJoin - rounds off the corners of a shape by filling an additional sector
 	// of disc centered at the common endpoint of connected segments.
 	// The radius for these rounded corners is equal to the line width.
-	RoundJoin = 1
+	RoundJoin LineJoin = 1
+
 	// BevelJoin - Fills an additional triangular area between the common endpoint
 	// of connected segments, and the separate outside rectangular corners of each segment.
-	BevelJoin = 2
+	BevelJoin LineJoin = 2
 
 	// ButtCap - the ends of lines are squared off at the endpoints. Default value.
-	ButtCap = 0
+	ButtCap LineCap = 0
+
 	// RoundCap - the ends of lines are rounded.
-	RoundCap = 1
+	RoundCap LineCap = 1
+
 	// SquareCap - the ends of lines are squared off by adding a box with an equal width
 	// and half the height of the line's thickness.
-	SquareCap = 2
+	SquareCap LineCap = 2
 
 	// AlphabeticBaseline - the text baseline is the normal alphabetic baseline. Default value.
 	AlphabeticBaseline = 0
+
 	// TopBaseline - the text baseline is the top of the em square.
 	TopBaseline = 1
+
 	// MiddleBaseline - the text baseline is the middle of the em square.
 	MiddleBaseline = 2
+
 	// BottomBaseline - the text baseline is the bottom of the bounding box.
 	// This differs from the ideographic baseline in that the ideographic baseline doesn't consider descenders.
 	BottomBaseline = 3
+
 	// HangingBaseline - the text baseline is the hanging baseline. (Used by Tibetan and other Indic scripts.)
 	HangingBaseline = 4
+
 	// IdeographicBaseline - the text baseline is the ideographic baseline; this is
 	// the bottom of the body of the characters, if the main body of characters protrudes
 	// beneath the alphabetic baseline. (Used by Chinese, Japanese, and Korean scripts.)
@@ -46,6 +62,7 @@ const (
 	// StartAlign - the text is aligned at the normal start of the line (left-aligned
 	// for left-to-right locales, right-aligned for right-to-left locales).
 	StartAlign = 3
+
 	// EndAlign - the text is aligned at the normal end of the line (right-aligned
 	// for left-to-right locales, left-aligned for right-to-left locales).
 	EndAlign = 4
@@ -91,7 +108,7 @@ type TextMetrics struct {
 	Right float64
 }
 
-// Canvas is a drawing interface
+// Canvas is a drawing interface used by the [CanvasView]
 type Canvas interface {
 	// View return the view for the drawing
 	View() CanvasView
@@ -112,15 +129,15 @@ type Canvas interface {
 	ClipPath(path Path)
 
 	// SetScale adds a scaling transformation to the canvas units horizontally and/or vertically.
-	//   x - scaling factor in the horizontal direction. A negative value flips pixels across
+	//   * x - scaling factor in the horizontal direction. A negative value flips pixels across
 	//       the vertical axis. A value of 1 results in no horizontal scaling;
-	//   y - scaling factor in the vertical direction. A negative value flips pixels across
+	//   * y - scaling factor in the vertical direction. A negative value flips pixels across
 	//       the horizontal axis. A value of 1 results in no vertical scaling.
 	SetScale(x, y float64)
 
 	// SetTranslation adds a translation transformation to the current matrix.
-	//   x - distance to move in the horizontal direction. Positive values are to the right, and negative to the left;
-	//   y - distance to move in the vertical direction. Positive values are down, and negative are up.
+	//   * x - distance to move in the horizontal direction. Positive values are to the right, and negative to the left;
+	//   * y - distance to move in the vertical direction. Positive values are down, and negative are up.
 	SetTranslation(x, y float64)
 
 	// SetRotation adds a rotation to the transformation matrix.
@@ -130,12 +147,13 @@ type Canvas interface {
 	// SetTransformation multiplies the current transformation with the matrix described by the arguments
 	// of this method. This lets you scale, rotate, translate (move), and skew the context.
 	// The transformation matrix is described by:
-	// ⎡ xScale xSkew  dx ⎤
-	// ⎢ ySkew  yScale dy ⎥
-	// ⎣   0      0     1 ⎦
-	//   xScale, yScale - horizontal and vertical scaling. A value of 1 results in no scaling;
-	//   xSkew, ySkew - horizontal and vertical skewing;
-	//   dx, dy - horizontal and vertical translation (moving).
+	//  ⎡ xScale xSkew  dx ⎤
+	//  ⎢ ySkew  yScale dy ⎥
+	//  ⎣   0      0     1 ⎦
+	// where
+	//   * xScale, yScale - horizontal and vertical scaling. A value of 1 results in no scaling;
+	//   * xSkew, ySkew - horizontal and vertical skewing;
+	//   * dx, dy - horizontal and vertical translation (moving).
 	SetTransformation(xScale, yScale, xSkew, ySkew, dx, dy float64)
 
 	// ResetTransformation resets the current transform to the identity matrix
@@ -148,45 +166,64 @@ type Canvas interface {
 	SetSolidColorStrokeStyle(color Color)
 
 	// SetLinearGradientFillStyle sets a gradient along the line connecting two given coordinates to use inside shapes
-	//   x0, y0 - coordinates of the start point;
-	//   x1, y1 - coordinates of the end point;
-	//   startColor, endColor - the start and end color
-	//   stopPoints - the array of stop points
+	//   * x0, y0 - coordinates of the start point;
+	//   * x1, y1 - coordinates of the end point;
+	//   * startColor, endColor - the start and end color
+	//   * stopPoints - the array of stop points
 	SetLinearGradientFillStyle(x0, y0 float64, color0 Color, x1, y1 float64, color1 Color, stopPoints []GradientPoint)
 
 	// SetLinearGradientStrokeStyle sets a gradient along the line connecting two given coordinates to use for the strokes (outlines) around shapes
-	//   x0, y0 - coordinates of the start point;
-	//   x1, y1 - coordinates of the end point;
-	//   color0, color1 - the start and end color
-	//   stopPoints - the array of stop points
+	//   * x0, y0 - coordinates of the start point;
+	//   * x1, y1 - coordinates of the end point;
+	//   * color0, color1 - the start and end color
+	//   * stopPoints - the array of stop points
 	SetLinearGradientStrokeStyle(x0, y0 float64, color0 Color, x1, y1 float64, color1 Color, stopPoints []GradientPoint)
 
 	// SetRadialGradientFillStyle sets a radial gradient using the size and coordinates of two circles
 	// to use inside shapes
-	//   x0, y0 - coordinates of the center of the start circle;
-	//   r0 - the radius of the start circle;
-	//   x1, y1 - coordinates the center of the end circle;
-	//   r1 - the radius of the end circle;
-	//   color0, color1 - the start and end color
-	//   stopPoints - the array of stop points
+	//   * x0, y0 - coordinates of the center of the start circle;
+	//   * r0 - the radius of the start circle;
+	//   * x1, y1 - coordinates the center of the end circle;
+	//   * r1 - the radius of the end circle;
+	//   * color0, color1 - the start and end color
+	//   * stopPoints - the array of stop points
 	SetRadialGradientFillStyle(x0, y0, r0 float64, color0 Color, x1, y1, r1 float64, color1 Color, stopPoints []GradientPoint)
 
 	// SetRadialGradientStrokeStyle sets a radial gradient using the size and coordinates of two circles
 	// to use for the strokes (outlines) around shapes
-	//   x0, y0 - coordinates of the center of the start circle;
-	//   r0 - the radius of the start circle;
-	//   x1, y1 - coordinates the center of the end circle;
-	//   r1 - the radius of the end circle;
-	//   color0, color1 - the start and end color
-	//   stopPoints - the array of stop points
+	//   * x0, y0 - coordinates of the center of the start circle;
+	//   * r0 - the radius of the start circle;
+	//   * x1, y1 - coordinates the center of the end circle;
+	//   * r1 - the radius of the end circle;
+	//   * color0, color1 - the start and end color
+	//   * stopPoints - the array of stop points
 	SetRadialGradientStrokeStyle(x0, y0, r0 float64, color0 Color, x1, y1, r1 float64, color1 Color, stopPoints []GradientPoint)
 
+	// SetConicGradientFillStyle sets a conic gradient around a point
+	// to use inside shapes
+	//   * x, y - coordinates of the center of the conic gradient in pilels;
+	//   * startAngle - the angle at which to begin the gradient, in radians. The angle starts from a line going horizontally right from the center, and proceeds clockwise.
+	//   * startColor - the start color;
+	//   * endColor - the end color;
+	//   * stopPoints - the array of stop points. The Pos field of GradientPoint, in the range from 0 to 1, specifies the angle in turns.
+	SetConicGradientFillStyle(x, y, startAngle float64, startColor, endColor Color, stopPoints []GradientPoint)
+
+	// SetConicGradientFillStyle sets a conic gradient around a point
+	// to use inside shapes
+	//   * x, y - coordinates of the center of the conic gradient in pilels;
+	//   * startAngle - the angle at which to begin the gradient, in radians. The angle starts from a line going horizontally right from the center, and proceeds clockwise.
+	//   * startColor - the start color;
+	//   * endColor - the end color;
+	//   * stopPoints - the array of stop points. The Pos field of GradientPoint, in the range from 0 to 1, specifies the angle in turns.
+	SetConicGradientStrokeStyle(x, y, startAngle float64, startColor, endColor Color, stopPoints []GradientPoint)
+
 	// SetImageFillStyle set the image as the filling pattern.
-	//   repeat - indicating how to repeat the pattern's image. Possible values are:
-	//     NoRepeat (0) - neither direction,
-	//     RepeatXY (1) - both directions,
-	//     RepeatX (2) - horizontal only,
-	//     RepeatY (3) - vertical only.
+	//
+	// repeat - indicating how to repeat the pattern's image. Possible values are:
+	//   * NoRepeat (0) - neither direction,
+	//   * RepeatXY (1) - both directions,
+	//   * RepeatX (2) - horizontal only,
+	//   * RepeatY (3) - vertical only.
 	SetImageFillStyle(image Image, repeat int)
 
 	// SetLineWidth the line width, in coordinate space units. Zero, negative, Infinity, and NaN values are ignored.
@@ -194,11 +231,11 @@ type Canvas interface {
 
 	// SetLineJoin sets the shape used to join two line segments where they meet.
 	// Valid values: MiterJoin (0), RoundJoin (1), BevelJoin (2). All other values are ignored.
-	SetLineJoin(join int)
+	SetLineJoin(join LineJoin)
 
 	// SetLineJoin sets the shape used to draw the end points of lines.
 	// Valid values: ButtCap (0), RoundCap (1), SquareCap (2). All other values are ignored.
-	SetLineCap(cap int)
+	SetLineCap(cap LineCap)
 
 	// SetLineDash sets the line dash pattern used when stroking lines.
 	// dash - an array of values that specify alternating lengths of lines and gaps which describe the pattern.
@@ -223,51 +260,67 @@ type Canvas interface {
 	SetTextAlign(align int)
 
 	// SetShadow sets shadow parameters:
-	//   offsetX, offsetY - the distance that shadows will be offset horizontally and vertically;
-	//   blur - the amount of blur applied to shadows. Must be non-negative;
-	//   color - the color of shadows.
+	//   * offsetX, offsetY - the distance that shadows will be offset horizontally and vertically;
+	//   * blur - the amount of blur applied to shadows. Must be non-negative;
+	//   * color - the color of shadows.
 	SetShadow(offsetX, offsetY, blur float64, color Color)
+
 	// ResetShadow sets shadow parameters to default values (invisible shadow)
 	ResetShadow()
 
 	// ClearRect erases the pixels in a rectangular area by setting them to transparent black
 	ClearRect(x, y, width, height float64)
+
 	// FillRect draws a rectangle that is filled according to the current FillStyle.
 	FillRect(x, y, width, height float64)
+
 	// StrokeRect draws a rectangle that is stroked (outlined) according to the current strokeStyle
 	// and other context settings
 	StrokeRect(x, y, width, height float64)
+
 	// FillAndStrokeRect draws a rectangle that is filled according to the current FillStyle and
 	// is stroked (outlined) according to the current strokeStyle and other context settings
 	FillAndStrokeRect(x, y, width, height float64)
 
 	// FillRoundedRect draws a rounded rectangle that is filled according to the current FillStyle.
 	FillRoundedRect(x, y, width, height, r float64)
+
 	// StrokeRoundedRect draws a rounded rectangle that is stroked (outlined) according
 	// to the current strokeStyle and other context settings
 	StrokeRoundedRect(x, y, width, height, r float64)
+
 	// FillAndStrokeRoundedRect draws a rounded rectangle that is filled according to the current FillStyle
 	// and is stroked (outlined) according to the current strokeStyle and other context settings
 	FillAndStrokeRoundedRect(x, y, width, height, r float64)
 
 	// FillEllipse draws a ellipse that is filled according to the current FillStyle.
-	//   x, y - coordinates of the ellipse's center;
-	//   radiusX - the ellipse's major-axis radius. Must be non-negative;
-	//   radiusY - the ellipse's minor-axis radius. Must be non-negative;
-	//   rotation - the rotation of the ellipse, expressed in radians.
+	//   * x, y - coordinates of the ellipse's center;
+	//   * radiusX - the ellipse's major-axis radius. Must be non-negative;
+	//   * radiusY - the ellipse's minor-axis radius. Must be non-negative;
+	//   * rotation - the rotation of the ellipse, expressed in radians.
 	FillEllipse(x, y, radiusX, radiusY, rotation float64)
+
 	// StrokeRoundedRect draws a ellipse that is stroked (outlined) according
 	// to the current strokeStyle and other context settings
 	StrokeEllipse(x, y, radiusX, radiusY, rotation float64)
+
 	// FillAndStrokeEllipse draws a ellipse that is filled according to the current FillStyle
 	// and is stroked (outlined) according to the current strokeStyle and other context settings
 	FillAndStrokeEllipse(x, y, radiusX, radiusY, rotation float64)
 
+	// NewPath creates a new Path object
+	NewPath() Path
+
+	// NewPathFromSvg creates a new Path and initialize it by a string consisting of SVG path data
+	NewPathFromSvg(data string) Path
+
 	// FillPath draws a path that is filled according to the current FillStyle.
 	FillPath(path Path)
+
 	// StrokePath draws a path that is stroked (outlined) according to the current strokeStyle
 	// and other context settings
 	StrokePath(path Path)
+
 	// FillAndStrokeRect draws a path that is filled according to the current FillStyle and
 	// is stroked (outlined) according to the current strokeStyle and other context settings
 	FillAndStrokePath(path Path)
@@ -278,14 +331,17 @@ type Canvas interface {
 	// FillText draws a text string at the specified coordinates, filling the string's characters
 	// with the current FillStyle
 	FillText(x, y float64, text string)
+
 	// StrokeText strokes — that is, draws the outlines of — the characters of a text string
 	// at the specified coordinates
 	StrokeText(x, y float64, text string)
 
 	// DrawImage draws the image at the (x, y) position
 	DrawImage(x, y float64, image Image)
+
 	// DrawImageInRect draws the image in the rectangle (x, y, width, height), scaling in height and width if necessary
 	DrawImageInRect(x, y, width, height float64, image Image)
+
 	// DrawImageFragment draws the fragment (described by srcX, srcY, srcWidth, srcHeight) of image
 	// in the rectangle (dstX, dstY, dstWidth, dstHeight), scaling in height and width if necessary
 	DrawImageFragment(srcX, srcY, srcWidth, srcHeight, dstX, dstY, dstWidth, dstHeight float64, image Image)
@@ -299,10 +355,13 @@ type canvasData struct {
 }
 
 func newCanvas(view CanvasView) Canvas {
+	session := view.Session()
+	if !session.canvasStart(view.htmlID()) {
+		return nil
+	}
 	canvas := new(canvasData)
 	canvas.view = view
-	canvas.session = view.Session()
-	canvas.session.canvasStart(view.htmlID())
+	canvas.session = session
 	return canvas
 }
 
@@ -343,8 +402,7 @@ func (canvas *canvasData) ClipRect(x, y, width, height float64) {
 }
 
 func (canvas *canvasData) ClipPath(path Path) {
-	path.create(canvas.session)
-	canvas.session.callCanvasFunc("clip")
+	canvas.session.callCanvasFunc("clip", path.obj())
 }
 
 func (canvas *canvasData) SetScale(x, y float64) {
@@ -427,6 +485,30 @@ func (canvas *canvasData) SetRadialGradientStrokeStyle(x0, y0, r0 float64, color
 	canvas.session.updateCanvasProperty("strokeStyle", gradient)
 }
 
+func (canvas *canvasData) createConicGradient(x, y, startAngle float64, startColor, endColor Color, stopPoints []GradientPoint) any {
+	gradient := canvas.session.createCanvasVar("createConicGradient", startAngle, x, y)
+	canvas.session.callCanvasVarFunc(gradient, "addColorStop", 0, startColor.cssString())
+
+	for _, point := range stopPoints {
+		if point.Offset >= 0 && point.Offset <= 1 {
+			canvas.session.callCanvasVarFunc(gradient, "addColorStop", point.Offset, point.Color.cssString())
+		}
+	}
+
+	canvas.session.callCanvasVarFunc(gradient, "addColorStop", 1, endColor.cssString())
+	return gradient
+}
+
+func (canvas *canvasData) SetConicGradientFillStyle(x, y, startAngle float64, startColor, endColor Color, stopPoints []GradientPoint) {
+	gradient := canvas.createConicGradient(x, y, startAngle, startColor, endColor, stopPoints)
+	canvas.session.updateCanvasProperty("fillStyle", gradient)
+}
+
+func (canvas *canvasData) SetConicGradientStrokeStyle(x, y, startAngle float64, startColor, endColor Color, stopPoints []GradientPoint) {
+	gradient := canvas.createConicGradient(x, y, startAngle, startColor, endColor, stopPoints)
+	canvas.session.updateCanvasProperty("strokeStyle", gradient)
+}
+
 func (canvas *canvasData) SetImageFillStyle(image Image, repeat int) {
 	if image == nil || image.LoadingStatus() != ImageReady {
 		return
@@ -459,7 +541,7 @@ func (canvas *canvasData) SetLineWidth(width float64) {
 	}
 }
 
-func (canvas *canvasData) SetLineJoin(join int) {
+func (canvas *canvasData) SetLineJoin(join LineJoin) {
 	switch join {
 	case MiterJoin:
 		canvas.session.updateCanvasProperty("lineJoin", "miter")
@@ -472,7 +554,7 @@ func (canvas *canvasData) SetLineJoin(join int) {
 	}
 }
 
-func (canvas *canvasData) SetLineCap(cap int) {
+func (canvas *canvasData) SetLineCap(cap LineCap) {
 	switch cap {
 	case ButtCap:
 		canvas.session.updateCanvasProperty("lineCap", "butt")
@@ -776,19 +858,16 @@ func (canvas *canvasData) StrokeText(x, y float64, text string) {
 }
 
 func (canvas *canvasData) FillPath(path Path) {
-	path.create(canvas.session)
-	canvas.session.callCanvasFunc("fill")
+	canvas.session.callCanvasFunc("fill", path.obj())
 }
 
 func (canvas *canvasData) StrokePath(path Path) {
-	path.create(canvas.session)
-	canvas.session.callCanvasFunc("stroke")
+	canvas.session.callCanvasFunc("stroke", path.obj())
 }
 
 func (canvas *canvasData) FillAndStrokePath(path Path) {
-	path.create(canvas.session)
-	canvas.session.callCanvasFunc("fill")
-	canvas.session.callCanvasFunc("stroke")
+	canvas.session.callCanvasFunc("fill", path.obj())
+	canvas.session.callCanvasFunc("stroke", path.obj())
 }
 
 func (canvas *canvasData) DrawLine(x0, y0, x1, y1 float64) {

canvasView.go

@@ -1,21 +1,23 @@
 package rui
 
-import "strings"
-
-// DrawFunction is the constant for the "draw-function" property tag.
-// The "draw-function" property sets the draw function of CanvasView.
-// The function should have the following format: func(Canvas)
-const DrawFunction = "draw-function"
+// DrawFunction is the constant for "draw-function" property tag.
+//
+// Used by `CanvasView`.
+// Property sets the draw function of `CanvasView`.
+//
+// Supported types: `func(Canvas)`.
+const DrawFunction PropertyName = "draw-function"
 
 // CanvasView interface of a custom draw view
 type CanvasView interface {
 	View
+
+	// Redraw forces CanvasView to redraw its content
 	Redraw()
 }
 
 type canvasViewData struct {
 	viewData
-	drawer func(Canvas)
 }
 
 // NewCanvasView creates the new custom draw view
@@ -27,21 +29,21 @@ func NewCanvasView(session Session, params Params) CanvasView {
 }
 
 func newCanvasView(session Session) View {
-	return NewCanvasView(session, nil)
+	return new(canvasViewData)
 }
 
 // Init initialize fields of ViewsContainer by default values
 func (canvasView *canvasViewData) init(session Session) {
 	canvasView.viewData.init(session)
 	canvasView.tag = "CanvasView"
+	canvasView.normalize = normalizeCanvasViewTag
+	canvasView.set = canvasView.setFunc
+	canvasView.remove = canvasView.removeFunc
+	canvasView.changed = canvasView.propertyChanged
 }
 
-func (canvasView *canvasViewData) String() string {
-	return getViewString(canvasView, nil)
-}
-
-func (canvasView *canvasViewData) normalizeTag(tag string) string {
-	tag = strings.ToLower(tag)
+func normalizeCanvasViewTag(tag PropertyName) PropertyName {
+	tag = defaultNormalize(tag)
 	switch tag {
 	case "draw-func":
 		tag = DrawFunction
@@ -49,51 +51,39 @@ func (canvasView *canvasViewData) normalizeTag(tag string) string {
 	return tag
 }
 
-func (canvasView *canvasViewData) Remove(tag string) {
-	canvasView.remove(canvasView.normalizeTag(tag))
-}
-
-func (canvasView *canvasViewData) remove(tag string) {
+func (canvasView *canvasViewData) removeFunc(tag PropertyName) []PropertyName {
 	if tag == DrawFunction {
-		canvasView.drawer = nil
-		canvasView.Redraw()
-		canvasView.propertyChangedEvent(tag)
-	} else {
-		canvasView.viewData.remove(tag)
+		if canvasView.getRaw(DrawFunction) != nil {
+			canvasView.setRaw(DrawFunction, nil)
+			canvasView.Redraw()
+			return []PropertyName{DrawFunction}
+		}
+		return []PropertyName{}
 	}
+
+	return canvasView.viewData.removeFunc(tag)
 }
 
-func (canvasView *canvasViewData) Set(tag string, value any) bool {
-	return canvasView.set(canvasView.normalizeTag(tag), value)
-}
-
-func (canvasView *canvasViewData) set(tag string, value any) bool {
+func (canvasView *canvasViewData) setFunc(tag PropertyName, value any) []PropertyName {
 	if tag == DrawFunction {
-		if value == nil {
-			canvasView.drawer = nil
-		} else if fn, ok := value.(func(Canvas)); ok {
-			canvasView.drawer = fn
+		if fn, ok := value.(func(Canvas)); ok {
+			canvasView.setRaw(DrawFunction, fn)
 		} else {
 			notCompatibleType(tag, value)
-			return false
+			return nil
 		}
-		canvasView.Redraw()
-		canvasView.propertyChangedEvent(tag)
-		return true
+		return []PropertyName{DrawFunction}
 	}
 
-	return canvasView.viewData.set(tag, value)
+	return canvasView.viewData.setFunc(tag, value)
 }
 
-func (canvasView *canvasViewData) Get(tag string) any {
-	return canvasView.get(canvasView.normalizeTag(tag))
-}
-
-func (canvasView *canvasViewData) get(tag string) any {
+func (canvasView *canvasViewData) propertyChanged(tag PropertyName) {
 	if tag == DrawFunction {
-		return canvasView.drawer
+		canvasView.Redraw()
+	} else {
+		canvasView.viewData.propertyChanged(tag)
 	}
-	return canvasView.viewData.get(tag)
 }
 
 func (canvasView *canvasViewData) htmlTag() string {
@@ -101,14 +91,14 @@ func (canvasView *canvasViewData) htmlTag() string {
 }
 
 func (canvasView *canvasViewData) Redraw() {
-	if canvasView.drawer != nil {
-		canvas := newCanvas(canvasView)
-		canvas.ClearRect(0, 0, canvasView.frame.Width, canvasView.frame.Height)
-		if canvasView.drawer != nil {
-			canvasView.drawer(canvas)
+	canvas := newCanvas(canvasView)
+	canvas.ClearRect(0, 0, canvasView.frame.Width, canvasView.frame.Height)
+	if value := canvasView.getRaw(DrawFunction); value != nil {
+		if drawer, ok := value.(func(Canvas)); ok {
+			drawer(canvas)
 		}
-		canvas.finishDraw()
 	}
+	canvas.finishDraw()
 }
 
 func (canvasView *canvasViewData) onResize(self View, x, y, width, height float64) {

checkbox.go

@@ -5,183 +5,149 @@ import (
 )
 
 // CheckboxChangedEvent is the constant for "checkbox-event" property tag.
-// The "checkbox-event" event occurs when the checkbox becomes checked/unchecked.
-// The main listener format: func(Checkbox, bool), where the second argument is the checkbox state.
-const CheckboxChangedEvent = "checkbox-event"
+//
+// Used by `Checkbox`.
+// Event occurs when the checkbox becomes checked/unchecked.
+//
+// General listener format:
+//
+//	func(checkbox rui.Checkbox, checked bool)
+//
+// where:
+//   - checkbox - Interface of a checkbox which generated this event,
+//   - checked - Checkbox state.
+//
+// Allowed listener formats:
+//
+//	func(checkbox rui.Checkbox)
+//	func(checked bool)
+//	func()
+const CheckboxChangedEvent PropertyName = "checkbox-event"
 
-// Checkbox - checkbox view
+// Checkbox represent a Checkbox view
 type Checkbox interface {
 	ViewsContainer
 }
 
 type checkboxData struct {
 	viewsContainerData
-	checkedListeners []func(Checkbox, bool)
 }
 
 // NewCheckbox create new Checkbox object and return it
 func NewCheckbox(session Session, params Params) Checkbox {
 	view := new(checkboxData)
 	view.init(session)
-	setInitParams(view, Params{
-		ClickEvent:   checkboxClickListener,
-		KeyDownEvent: checkboxKeyListener,
-	})
 	setInitParams(view, params)
 	return view
 }
 
 func newCheckbox(session Session) View {
-	return NewCheckbox(session, nil)
+	return new(checkboxData)
 }
 
 func (button *checkboxData) init(session Session) {
 	button.viewsContainerData.init(session)
 	button.tag = "Checkbox"
 	button.systemClass = "ruiGridLayout ruiCheckbox"
-	button.checkedListeners = []func(Checkbox, bool){}
-}
+	button.set = button.setFunc
+	button.remove = button.removeFunc
+	button.changed = button.propertyChanged
 
-func (button *checkboxData) String() string {
-	return getViewString(button, nil)
+	button.setRaw(ClickEvent, []func(View, MouseEvent){checkboxClickListener})
+	button.setRaw(KeyDownEvent, []func(View, KeyEvent){checkboxKeyListener})
 }
 
 func (button *checkboxData) Focusable() bool {
 	return true
 }
 
-func (button *checkboxData) Get(tag string) any {
-	switch strings.ToLower(tag) {
-	case CheckboxChangedEvent:
-		return button.checkedListeners
-	}
-
-	return button.viewsContainerData.Get(tag)
-}
-
-func (button *checkboxData) Set(tag string, value any) bool {
-	return button.set(tag, value)
-}
-
-func (button *checkboxData) set(tag string, value any) bool {
+func (button *checkboxData) propertyChanged(tag PropertyName) {
 	switch tag {
-	case CheckboxChangedEvent:
-		if !button.setChangedListener(value) {
-			notCompatibleType(tag, value)
-			return false
-		}
 
 	case Checked:
-		oldChecked := button.checked()
-		if !button.setBoolProperty(Checked, value) {
-			return false
-		}
-		if button.created {
-			checked := button.checked()
-			if checked != oldChecked {
-				button.changedCheckboxState(checked)
+		session := button.Session()
+		checked := IsCheckboxChecked(button)
+		if listeners := GetCheckboxChangedListeners(button); len(listeners) > 0 {
+			for _, listener := range listeners {
+				listener(button, checked)
 			}
 		}
 
+		buffer := allocStringBuilder()
+		defer freeStringBuilder(buffer)
+
+		checkboxHtml(button, buffer, checked)
+		session.updateInnerHTML(button.htmlID()+"checkbox", buffer.String())
+
 	case CheckboxHorizontalAlign, CheckboxVerticalAlign:
-		if !button.setEnumProperty(tag, value, enumProperties[tag].values) {
-			return false
-		}
-		if button.created {
-			htmlID := button.htmlID()
-			updateCSSStyle(htmlID, button.session)
-			updateInnerHTML(htmlID, button.session)
-		}
+		htmlID := button.htmlID()
+		session := button.Session()
+		updateCSSStyle(htmlID, session)
+		updateInnerHTML(htmlID, session)
 
 	case VerticalAlign:
-		if !button.setEnumProperty(tag, value, enumProperties[tag].values) {
-			return false
-		}
-		if button.created {
-			button.session.updateCSSProperty(button.htmlID()+"content", "align-items", button.cssVerticalAlign())
-		}
+		button.Session().updateCSSProperty(button.htmlID()+"content", "align-items", checkboxVerticalAlignCSS(button))
 
 	case HorizontalAlign:
-		if !button.setEnumProperty(tag, value, enumProperties[tag].values) {
-			return false
-		}
-		if button.created {
-			button.session.updateCSSProperty(button.htmlID()+"content", "justify-items", button.cssHorizontalAlign())
-		}
+		button.Session().updateCSSProperty(button.htmlID()+"content", "justify-items", checkboxHorizontalAlignCSS(button))
 
-	case CellVerticalAlign, CellHorizontalAlign, CellWidth, CellHeight:
-		return false
+	case AccentColor:
+		updateInnerHTML(button.htmlID(), button.Session())
 
 	default:
-		return button.viewsContainerData.set(tag, value)
+		button.viewsContainerData.propertyChanged(tag)
 	}
-
-	button.propertyChangedEvent(tag)
-	return true
 }
 
-func (button *checkboxData) Remove(tag string) {
-	button.remove(strings.ToLower(tag))
-}
-
-func (button *checkboxData) remove(tag string) {
+func (button *checkboxData) setFunc(tag PropertyName, value any) []PropertyName {
 	switch tag {
 	case ClickEvent:
-		if !button.viewsContainerData.set(ClickEvent, checkboxClickListener) {
-			delete(button.properties, tag)
+		if listeners, ok := valueToOneArgEventListeners[View, MouseEvent](value); ok && listeners != nil {
+			listeners = append(listeners, checkboxClickListener)
+			button.setRaw(tag, listeners)
+			return []PropertyName{tag}
 		}
+		return nil
 
 	case KeyDownEvent:
-		if !button.viewsContainerData.set(KeyDownEvent, checkboxKeyListener) {
-			delete(button.properties, tag)
+		if listeners, ok := valueToOneArgEventListeners[View, KeyEvent](value); ok && listeners != nil {
+			listeners = append(listeners, checkboxKeyListener)
+			button.setRaw(tag, listeners)
+			return []PropertyName{tag}
 		}
+		return nil
 
 	case CheckboxChangedEvent:
-		if len(button.checkedListeners) > 0 {
-			button.checkedListeners = []func(Checkbox, bool){}
-		}
+		return setOneArgEventListener[Checkbox, bool](button, tag, value)
 
 	case Checked:
-		oldChecked := button.checked()
-		delete(button.properties, tag)
-		if button.created && oldChecked {
-			button.changedCheckboxState(false)
-		}
+		return setBoolProperty(button, Checked, value)
 
-	case CheckboxHorizontalAlign, CheckboxVerticalAlign:
-		delete(button.properties, tag)
-		if button.created {
-			htmlID := button.htmlID()
-			updateCSSStyle(htmlID, button.session)
-			updateInnerHTML(htmlID, button.session)
-		}
-
-	case VerticalAlign:
-		delete(button.properties, tag)
-		if button.created {
-			button.session.updateCSSProperty(button.htmlID()+"content", "align-items", button.cssVerticalAlign())
-		}
-
-	case HorizontalAlign:
-		delete(button.properties, tag)
-		if button.created {
-			button.session.updateCSSProperty(button.htmlID()+"content", "justify-items", button.cssHorizontalAlign())
-		}
-
-	default:
-		button.viewsContainerData.remove(tag)
-		return
+	case CellVerticalAlign, CellHorizontalAlign, CellWidth, CellHeight:
+		ErrorLogF(`"%s" property is not compatible with the BoundsProperty`, string(tag))
+		return nil
 	}
-	button.propertyChangedEvent(tag)
+
+	return button.viewsContainerData.setFunc(tag, value)
 }
 
-func (button *checkboxData) checked() bool {
-	checked, _ := boolProperty(button, Checked, button.Session())
-	return checked
+func (button *checkboxData) removeFunc(tag PropertyName) []PropertyName {
+	switch tag {
+	case ClickEvent:
+		button.setRaw(ClickEvent, []func(View, MouseEvent){checkboxClickListener})
+		return []PropertyName{ClickEvent}
+
+	case KeyDownEvent:
+		button.setRaw(KeyDownEvent, []func(View, KeyEvent){checkboxKeyListener})
+		return []PropertyName{ClickEvent}
+	}
+
+	return button.viewsContainerData.removeFunc(tag)
 }
 
+/*
 func (button *checkboxData) changedCheckboxState(state bool) {
-	for _, listener := range button.checkedListeners {
+	for _, listener := range GetCheckboxChangedListeners(button) {
 		listener(button, state)
 	}
 
@@ -191,8 +157,9 @@ func (button *checkboxData) changedCheckboxState(state bool) {
 	button.htmlCheckbox(buffer, state)
 	button.Session().updateInnerHTML(button.htmlID()+"checkbox", buffer.String())
 }
+*/
 
-func checkboxClickListener(view View) {
+func checkboxClickListener(view View, _ MouseEvent) {
 	view.Set(Checked, !IsCheckboxChecked(view))
 	BlurView(view)
 }
@@ -204,17 +171,6 @@ func checkboxKeyListener(view View, event KeyEvent) {
 	}
 }
 
-func (button *checkboxData) setChangedListener(value any) bool {
-	listeners, ok := valueToEventListeners[Checkbox, bool](value)
-	if !ok {
-		return false
-	} else if listeners == nil {
-		listeners = []func(Checkbox, bool){}
-	}
-	button.checkedListeners = listeners
-	return true
-}
-
 func (button *checkboxData) cssStyle(self View, builder cssBuilder) {
 	session := button.Session()
 	vAlign := GetCheckboxVerticalAlign(button)
@@ -241,10 +197,11 @@ func (button *checkboxData) cssStyle(self View, builder cssBuilder) {
 	builder.add("align-items", "stretch")
 	builder.add("justify-items", "stretch")
 
-	button.viewsContainerData.cssStyle(self, builder)
+	button.viewData.cssStyle(self, builder)
 }
 
-func (button *checkboxData) htmlCheckbox(buffer *strings.Builder, checked bool) (int, int) {
+func checkboxHtml(button View, buffer *strings.Builder, checked bool) (int, int) {
+	//func (button *checkboxData) htmlCheckbox(buffer *strings.Builder, checked bool) (int, int) {
 	vAlign := GetCheckboxVerticalAlign(button)
 	hAlign := GetCheckboxHorizontalAlign(button)
 
@@ -278,10 +235,16 @@ func (button *checkboxData) htmlCheckbox(buffer *strings.Builder, checked bool)
 	}
 
 	buffer.WriteString(`">`)
+
+	accentColor := Color(0)
+	if color := GetAccentColor(button, ""); color != 0 {
+		accentColor = color
+	}
+
 	if checked {
-		buffer.WriteString(button.Session().checkboxOnImage())
+		buffer.WriteString(button.Session().checkboxOnImage(accentColor))
 	} else {
-		buffer.WriteString(button.Session().checkboxOffImage())
+		buffer.WriteString(button.Session().checkboxOffImage(accentColor))
 	}
 	buffer.WriteString(`</div>`)
 
@@ -290,7 +253,7 @@ func (button *checkboxData) htmlCheckbox(buffer *strings.Builder, checked bool)
 
 func (button *checkboxData) htmlSubviews(self View, buffer *strings.Builder) {
 
-	vCheckboxAlign, hCheckboxAlign := button.htmlCheckbox(buffer, IsCheckboxChecked(button))
+	vCheckboxAlign, hCheckboxAlign := checkboxHtml(button, buffer, IsCheckboxChecked(button))
 
 	buffer.WriteString(`<div id="`)
 	buffer.WriteString(button.htmlID())
@@ -308,11 +271,11 @@ func (button *checkboxData) htmlSubviews(self View, buffer *strings.Builder) {
 	}
 
 	buffer.WriteString(" align-items: ")
-	buffer.WriteString(button.cssVerticalAlign())
+	buffer.WriteString(checkboxVerticalAlignCSS(button))
 	buffer.WriteRune(';')
 
 	buffer.WriteString(" justify-items: ")
-	buffer.WriteString(button.cssHorizontalAlign())
+	buffer.WriteString(checkboxHorizontalAlignCSS(button))
 	buffer.WriteRune(';')
 
 	buffer.WriteString(`">`)
@@ -320,8 +283,8 @@ func (button *checkboxData) htmlSubviews(self View, buffer *strings.Builder) {
 	buffer.WriteString(`</div>`)
 }
 
-func (button *checkboxData) cssHorizontalAlign() string {
-	align := GetHorizontalAlign(button)
+func checkboxHorizontalAlignCSS(view View) string {
+	align := GetHorizontalAlign(view)
 	values := enumProperties[CellHorizontalAlign].cssValues
 	if align >= 0 && align < len(values) {
 		return values[align]
@@ -329,8 +292,8 @@ func (button *checkboxData) cssHorizontalAlign() string {
 	return values[0]
 }
 
-func (button *checkboxData) cssVerticalAlign() string {
-	align := GetVerticalAlign(button)
+func checkboxVerticalAlignCSS(view View) string {
+	align := GetVerticalAlign(view)
 	values := enumProperties[CellVerticalAlign].cssValues
 	if align >= 0 && align < len(values) {
 		return values[align]
@@ -355,3 +318,10 @@ func GetCheckboxVerticalAlign(view View, subviewID ...string) int {
 func GetCheckboxHorizontalAlign(view View, subviewID ...string) int {
 	return enumStyledProperty(view, subviewID, CheckboxHorizontalAlign, TopAlign, false)
 }
+
+// GetCheckboxChangedListeners returns the CheckboxChangedListener list of an Checkbox subview.
+// If there are no listeners then the empty list is returned
+// If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
+func GetCheckboxChangedListeners(view View, subviewID ...string) []func(Checkbox, bool) {
+	return getOneArgEventListeners[Checkbox, bool](view, subviewID, CheckboxChangedEvent)
+}

clipShape.go

@@ -0,0 +1,690 @@
+package rui
+
+import (
+	"fmt"
+	"strings"
+)
+
+type ClipShape string
+
+const (
+	InsetClip   ClipShape = "inset"
+	CircleClip  ClipShape = "circle"
+	EllipseClip ClipShape = "ellipse"
+	PolygonClip ClipShape = "polygon"
+)
+
+// ClipShapeProperty defines a View clipping area
+type ClipShapeProperty interface {
+	Properties
+	fmt.Stringer
+	stringWriter
+
+	// Shape returns the clip shape type
+	Shape() ClipShape
+	cssStyle(session Session) string
+	valid(session Session) bool
+}
+
+type insetClipData struct {
+	dataProperty
+}
+
+type ellipseClipData struct {
+	dataProperty
+}
+
+type circleClipData struct {
+	dataProperty
+}
+
+type polygonClipData struct {
+	dataProperty
+}
+
+// NewClipShapeProperty creates ClipShapeProperty.
+//
+// The following properties can be used for shapes:
+//
+// InsetClip:
+//   - "top" (Top) - offset (SizeUnit) from the top border of a View;
+//   - "right" (Right) - offset (SizeUnit) from the right border of a View;
+//   - "bottom" (Bottom) - offset (SizeUnit) from the bottom border of a View;
+//   - "left" (Left) - offset (SizeUnit) from the left border of a View;
+//   - "radius" (Radius) - corner radius (RadiusProperty).
+//
+// CircleClip:
+//   - "x" (X) - x-axis position (SizeUnit) of the circle clip center;
+//   - "y" (Y) - y-axis position (SizeUnit) of the circle clip center;
+//   - "radius" (Radius) - radius (SizeUnit) of the circle clip center.
+//
+// EllipseClip:
+//   - "x" (X) - x-axis position (SizeUnit) of the ellipse clip center;
+//   - "y" (Y) - y-axis position (SizeUnit) of the ellipse clip center;
+//   - "radius-x" (RadiusX) - x-axis radius (SizeUnit) of the ellipse clip center;
+//   - "radius-y" (RadiusY) - y-axis radius (SizeUnit) of the ellipse clip center.
+//
+// PolygonClip:
+//   - "points" (Points) - an array ([]SizeUnit) of corner points of the polygon in the following order: x1, y1, x2, y2, ….
+//
+// The function will return nil if no properties are specified, unsupported properties are specified, or at least one property has an invalid value.
+func NewClipShapeProperty(shape ClipShape, params Params) ClipShapeProperty {
+	if len(params) == 0 {
+		ErrorLog("No ClipShapeProperty params")
+		return nil
+	}
+
+	var result ClipShapeProperty
+
+	switch shape {
+	case InsetClip:
+		clip := new(insetClipData)
+		clip.init()
+		result = clip
+
+	case CircleClip:
+		clip := new(circleClipData)
+		clip.init()
+		result = clip
+
+	case EllipseClip:
+		clip := new(ellipseClipData)
+		clip.init()
+		result = clip
+
+	case PolygonClip:
+		clip := new(polygonClipData)
+		clip.init()
+		result = clip
+
+	default:
+		ErrorLog("Unknown ClipShape: " + string(shape))
+		return nil
+	}
+
+	for tag, value := range params {
+		if !result.Set(tag, value) {
+			return nil
+		}
+	}
+
+	return result
+}
+
+// NewInsetClip creates a rectangle View clipping area.
+//   - top - offset from the top border of a View;
+//   - right - offset from the right border of a View;
+//   - bottom - offset from the bottom border of a View;
+//   - left - offset from the left border of a View;
+//   - radius - corner radius, pass nil if you don't need to round corners
+func NewInsetClip(top, right, bottom, left SizeUnit, radius RadiusProperty) ClipShapeProperty {
+	clip := new(insetClipData)
+	clip.init()
+	clip.setRaw(Top, top)
+	clip.setRaw(Right, right)
+	clip.setRaw(Bottom, bottom)
+	clip.setRaw(Left, left)
+	if radius != nil {
+		clip.setRaw(Radius, radius)
+	}
+	return clip
+}
+
+// NewCircleClip creates a circle View clipping area.
+//   - x - x-axis position of the circle clip center;
+//   - y - y-axis position of the circle clip center;
+//   - radius - radius of the circle clip center.
+func NewCircleClip(x, y, radius SizeUnit) ClipShapeProperty {
+	clip := new(circleClipData)
+	clip.init()
+	clip.setRaw(X, x)
+	clip.setRaw(Y, y)
+	clip.setRaw(Radius, radius)
+	return clip
+}
+
+// NewEllipseClip creates a ellipse View clipping area.
+//   - x - x-axis position of the ellipse clip center;
+//   - y - y-axis position of the ellipse clip center;
+//   - rx - x-axis radius of the ellipse clip center;
+//   - ry - y-axis radius of the ellipse clip center.
+func NewEllipseClip(x, y, rx, ry SizeUnit) ClipShapeProperty {
+	clip := new(ellipseClipData)
+	clip.init()
+	clip.setRaw(X, x)
+	clip.setRaw(Y, y)
+	clip.setRaw(RadiusX, rx)
+	clip.setRaw(RadiusY, ry)
+	return clip
+}
+
+// NewPolygonClip creates a polygon View clipping area.
+//   - points - an array of corner points of the polygon in the following order: x1, y1, x2, y2, …
+//
+// The elements of the function argument can be or text constants,
+// or the text representation of SizeUnit, or elements of SizeUnit type.
+func NewPolygonClip(points []any) ClipShapeProperty {
+	clip := new(polygonClipData)
+	clip.init()
+	if polygonClipDataSet(clip, Points, points) != nil {
+		return clip
+	}
+	return nil
+}
+
+// NewPolygonPointsClip creates a polygon View clipping area.
+//   - points - an array of corner points of the polygon in the following order: x1, y1, x2, y2, …
+func NewPolygonPointsClip(points []SizeUnit) ClipShapeProperty {
+	clip := new(polygonClipData)
+	clip.init()
+	if polygonClipDataSet(clip, Points, points) != nil {
+		return clip
+	}
+	return nil
+}
+
+func (clip *insetClipData) init() {
+	clip.dataProperty.init()
+	clip.set = insetClipDataSet
+	clip.supportedProperties = []PropertyName{
+		Top, Right, Bottom, Left, Radius,
+		RadiusX, RadiusY, RadiusTopLeft, RadiusTopLeftX, RadiusTopLeftY,
+		RadiusTopRight, RadiusTopRightX, RadiusTopRightY,
+		RadiusBottomLeft, RadiusBottomLeftX, RadiusBottomLeftY,
+		RadiusBottomRight, RadiusBottomRightX, RadiusBottomRightY,
+	}
+}
+
+func (clip *insetClipData) Shape() ClipShape {
+	return InsetClip
+}
+
+func insetClipDataSet(properties Properties, tag PropertyName, value any) []PropertyName {
+	switch tag {
+	case Top, Right, Bottom, Left:
+		return setSizeProperty(properties, tag, value)
+
+	case Radius:
+		return setRadiusProperty(properties, value)
+
+	case RadiusX, RadiusY, RadiusTopLeft, RadiusTopLeftX, RadiusTopLeftY,
+		RadiusTopRight, RadiusTopRightX, RadiusTopRightY,
+		RadiusBottomLeft, RadiusBottomLeftX, RadiusBottomLeftY,
+		RadiusBottomRight, RadiusBottomRightX, RadiusBottomRightY:
+		if setRadiusPropertyElement(properties, tag, value) {
+			return []PropertyName{tag, Radius}
+		}
+		return nil
+	}
+
+	ErrorLogF(`"%s" property is not supported by the inset clip shape`, tag)
+	return nil
+}
+
+func (clip *insetClipData) String() string {
+	return runStringWriter(clip)
+}
+
+func (clip *insetClipData) writeString(buffer *strings.Builder, indent string) {
+	buffer.WriteString("inset { ")
+	comma := false
+	for _, tag := range []PropertyName{Top, Right, Bottom, Left, Radius} {
+		if value, ok := clip.properties[tag]; ok {
+			if comma {
+				buffer.WriteString(", ")
+			}
+			buffer.WriteString(string(tag))
+			buffer.WriteString(" = ")
+			writePropertyValue(buffer, tag, value, indent)
+			comma = true
+		}
+	}
+
+	buffer.WriteString(" }")
+}
+
+func (clip *insetClipData) cssStyle(session Session) string {
+
+	buffer := allocStringBuilder()
+	defer freeStringBuilder(buffer)
+
+	leadText := "inset("
+	for _, tag := range []PropertyName{Top, Right, Bottom, Left} {
+		value, _ := sizeProperty(clip, tag, session)
+		buffer.WriteString(leadText)
+		buffer.WriteString(value.cssString("0px", session))
+		leadText = " "
+	}
+
+	if radius := getRadiusProperty(clip); radius != nil {
+		buffer.WriteString(" round ")
+		buffer.WriteString(radius.BoxRadius(session).cssString(session))
+	}
+
+	buffer.WriteRune(')')
+	return buffer.String()
+}
+
+func (clip *insetClipData) valid(session Session) bool {
+	for _, tag := range []PropertyName{Top, Right, Bottom, Left, Radius, RadiusX, RadiusY} {
+		if value, ok := sizeProperty(clip, tag, session); ok && value.Type != Auto && value.Value != 0 {
+			return true
+		}
+	}
+	return false
+}
+
+func (clip *circleClipData) init() {
+	clip.dataProperty.init()
+	clip.set = circleClipDataSet
+	clip.supportedProperties = []PropertyName{X, Y, Radius}
+}
+
+func (clip *circleClipData) Shape() ClipShape {
+	return CircleClip
+}
+
+func circleClipDataSet(properties Properties, tag PropertyName, value any) []PropertyName {
+	switch tag {
+	case X, Y, Radius:
+		return setSizeProperty(properties, tag, value)
+	}
+
+	ErrorLogF(`"%s" property is not supported by the circle clip shape`, tag)
+	return nil
+}
+
+func (clip *circleClipData) String() string {
+	return runStringWriter(clip)
+}
+
+func (clip *circleClipData) writeString(buffer *strings.Builder, indent string) {
+	buffer.WriteString("circle { ")
+	comma := false
+	for _, tag := range []PropertyName{Radius, X, Y} {
+		if value, ok := clip.properties[tag]; ok {
+			if comma {
+				buffer.WriteString(", ")
+			}
+			buffer.WriteString(string(tag))
+			buffer.WriteString(" = ")
+			writePropertyValue(buffer, tag, value, indent)
+			comma = true
+		}
+	}
+
+	buffer.WriteString(" }")
+}
+
+func (clip *circleClipData) cssStyle(session Session) string {
+
+	buffer := allocStringBuilder()
+	defer freeStringBuilder(buffer)
+
+	buffer.WriteString("circle(")
+	r, _ := sizeProperty(clip, Radius, session)
+	buffer.WriteString(r.cssString("50%", session))
+
+	buffer.WriteString(" at ")
+	x, _ := sizeProperty(clip, X, session)
+	buffer.WriteString(x.cssString("50%", session))
+	buffer.WriteRune(' ')
+
+	y, _ := sizeProperty(clip, Y, session)
+	buffer.WriteString(y.cssString("50%", session))
+	buffer.WriteRune(')')
+
+	return buffer.String()
+}
+
+func (clip *circleClipData) valid(session Session) bool {
+	if value, ok := sizeProperty(clip, Radius, session); ok && value.Value == 0 {
+		return false
+	}
+	return true
+}
+
+func (clip *ellipseClipData) init() {
+	clip.dataProperty.init()
+	clip.set = ellipseClipDataSet
+	clip.supportedProperties = []PropertyName{X, Y, Radius, RadiusX, RadiusY}
+}
+
+func (clip *ellipseClipData) Shape() ClipShape {
+	return EllipseClip
+}
+
+func ellipseClipDataSet(properties Properties, tag PropertyName, value any) []PropertyName {
+	switch tag {
+	case X, Y, RadiusX, RadiusY:
+		return setSizeProperty(properties, tag, value)
+
+	case Radius:
+		if result := setSizeProperty(properties, RadiusX, value); result != nil {
+			properties.setRaw(RadiusY, properties.getRaw(RadiusX))
+			return append(result, RadiusY)
+		}
+		return nil
+	}
+
+	ErrorLogF(`"%s" property is not supported by the ellipse clip shape`, tag)
+	return nil
+}
+
+func (clip *ellipseClipData) String() string {
+	return runStringWriter(clip)
+}
+
+func (clip *ellipseClipData) writeString(buffer *strings.Builder, indent string) {
+	buffer.WriteString("ellipse { ")
+	comma := false
+	for _, tag := range []PropertyName{RadiusX, RadiusY, X, Y} {
+		if value, ok := clip.properties[tag]; ok {
+			if comma {
+				buffer.WriteString(", ")
+			}
+			buffer.WriteString(string(tag))
+			buffer.WriteString(" = ")
+			writePropertyValue(buffer, tag, value, indent)
+			comma = true
+		}
+	}
+
+	buffer.WriteString(" }")
+}
+
+func (clip *ellipseClipData) cssStyle(session Session) string {
+
+	buffer := allocStringBuilder()
+	defer freeStringBuilder(buffer)
+
+	rx, _ := sizeProperty(clip, RadiusX, session)
+	ry, _ := sizeProperty(clip, RadiusX, session)
+	buffer.WriteString("ellipse(")
+	buffer.WriteString(rx.cssString("50%", session))
+	buffer.WriteRune(' ')
+	buffer.WriteString(ry.cssString("50%", session))
+
+	buffer.WriteString(" at ")
+	x, _ := sizeProperty(clip, X, session)
+	buffer.WriteString(x.cssString("50%", session))
+	buffer.WriteRune(' ')
+
+	y, _ := sizeProperty(clip, Y, session)
+	buffer.WriteString(y.cssString("50%", session))
+	buffer.WriteRune(')')
+
+	return buffer.String()
+}
+
+func (clip *ellipseClipData) valid(session Session) bool {
+	rx, _ := sizeProperty(clip, RadiusX, session)
+	ry, _ := sizeProperty(clip, RadiusY, session)
+	return rx.Value != 0 && ry.Value != 0
+}
+
+func (clip *polygonClipData) init() {
+	clip.dataProperty.init()
+	clip.set = polygonClipDataSet
+	clip.supportedProperties = []PropertyName{Points}
+}
+
+func (clip *polygonClipData) Shape() ClipShape {
+	return PolygonClip
+}
+
+func polygonClipDataSet(properties Properties, tag PropertyName, value any) []PropertyName {
+	if Points == tag {
+		switch value := value.(type) {
+		case []any:
+			points := make([]any, len(value))
+			for i, val := range value {
+				switch val := val.(type) {
+				case string:
+					if isConstantName(val) {
+						points[i] = val
+					} else if size, ok := StringToSizeUnit(val); ok {
+						points[i] = size
+					} else {
+						notCompatibleType(tag, val)
+						return nil
+					}
+
+				case SizeUnit:
+					points[i] = val
+
+				default:
+					notCompatibleType(tag, val)
+					points[i] = AutoSize()
+					return nil
+				}
+			}
+			properties.setRaw(Points, points)
+			return []PropertyName{tag}
+
+		case []SizeUnit:
+			points := make([]any, len(value))
+			for i, point := range value {
+				points[i] = point
+			}
+			properties.setRaw(Points, points)
+			return []PropertyName{tag}
+
+		case string:
+			values := strings.Split(value, ",")
+			points := make([]any, len(values))
+			for i, val := range values {
+				val = strings.Trim(val, " \t\n\r")
+				if isConstantName(val) {
+					points[i] = val
+				} else if size, ok := StringToSizeUnit(val); ok {
+					points[i] = size
+				} else {
+					notCompatibleType(tag, val)
+					return nil
+				}
+			}
+			properties.setRaw(Points, points)
+			return []PropertyName{tag}
+		}
+	}
+	return nil
+}
+
+func (clip *polygonClipData) String() string {
+	return runStringWriter(clip)
+}
+
+func (clip *polygonClipData) points() []any {
+	if value := clip.getRaw(Points); value != nil {
+		if points, ok := value.([]any); ok {
+			return points
+		}
+	}
+	return nil
+}
+
+func (clip *polygonClipData) writeString(buffer *strings.Builder, indent string) {
+
+	buffer.WriteString("inset { ")
+
+	if points := clip.points(); points != nil {
+		buffer.WriteString(string(Points))
+		buffer.WriteString(` = "`)
+		for i, value := range points {
+			if i > 0 {
+				buffer.WriteString(", ")
+			}
+			writePropertyValue(buffer, "", value, indent)
+		}
+
+		buffer.WriteString(`" `)
+	}
+	buffer.WriteRune('}')
+}
+
+func (clip *polygonClipData) cssStyle(session Session) string {
+
+	points := clip.points()
+	count := len(points)
+	if count < 2 {
+		return ""
+	}
+
+	buffer := allocStringBuilder()
+	defer freeStringBuilder(buffer)
+
+	writePoint := func(value any) {
+		switch value := value.(type) {
+		case string:
+			if val, ok := session.resolveConstants(value); ok {
+				if size, ok := StringToSizeUnit(val); ok {
+					buffer.WriteString(size.cssString("0px", session))
+					return
+				}
+			}
+
+		case SizeUnit:
+			buffer.WriteString(value.cssString("0px", session))
+			return
+		}
+
+		buffer.WriteString("0px")
+	}
+
+	leadText := "polygon("
+	for i := 1; i < count; i += 2 {
+		buffer.WriteString(leadText)
+		writePoint(points[i-1])
+		buffer.WriteRune(' ')
+		writePoint(points[i])
+		leadText = ", "
+	}
+
+	buffer.WriteRune(')')
+	return buffer.String()
+}
+
+func (clip *polygonClipData) valid(session Session) bool {
+	return len(clip.points()) > 0
+}
+
+func parseClipShapeProperty(obj DataObject) ClipShapeProperty {
+	switch obj.Tag() {
+	case "inset":
+		clip := new(insetClipData)
+		clip.init()
+		for _, tag := range []PropertyName{Top, Right, Bottom, Left, Radius, RadiusX, RadiusY} {
+			if value, ok := obj.PropertyValue(string(tag)); ok {
+				insetClipDataSet(clip, tag, value)
+			}
+		}
+		return clip
+
+	case "circle":
+		clip := new(circleClipData)
+		clip.init()
+		for _, tag := range []PropertyName{X, Y, Radius} {
+			if value, ok := obj.PropertyValue(string(tag)); ok {
+				circleClipDataSet(clip, tag, value)
+			}
+		}
+		return clip
+
+	case "ellipse":
+		clip := new(ellipseClipData)
+		clip.init()
+		for _, tag := range []PropertyName{X, Y, RadiusX, RadiusY} {
+			if value, ok := obj.PropertyValue(string(tag)); ok {
+				ellipseClipDataSet(clip, tag, value)
+			}
+		}
+		return clip
+
+	case "polygon":
+		clip := new(polygonClipData)
+		clip.init()
+		if value, ok := obj.PropertyValue(string(Points)); ok {
+			polygonClipDataSet(clip, Points, value)
+		}
+		return clip
+	}
+
+	return nil
+}
+
+func setClipShapePropertyProperty(properties Properties, tag PropertyName, value any) []PropertyName {
+	switch value := value.(type) {
+	case ClipShapeProperty:
+		properties.setRaw(tag, value)
+		return []PropertyName{tag}
+
+	case string:
+		if isConstantName(value) {
+			properties.setRaw(tag, value)
+			return []PropertyName{tag}
+		}
+
+		if obj := NewDataObject(value); obj == nil {
+			if clip := parseClipShapeProperty(obj); clip != nil {
+				properties.setRaw(tag, clip)
+				return []PropertyName{tag}
+			}
+		}
+
+	case DataObject:
+		if clip := parseClipShapeProperty(value); clip != nil {
+			properties.setRaw(tag, clip)
+			return []PropertyName{tag}
+		}
+
+	case DataValue:
+		if value.IsObject() {
+			if clip := parseClipShapeProperty(value.Object()); clip != nil {
+				properties.setRaw(tag, clip)
+				return []PropertyName{tag}
+			}
+		}
+	}
+
+	notCompatibleType(tag, value)
+	return nil
+}
+
+func getClipShapeProperty(prop Properties, tag PropertyName, session Session) ClipShapeProperty {
+	if value := prop.getRaw(tag); value != nil {
+		switch value := value.(type) {
+		case ClipShapeProperty:
+			return value
+
+		case string:
+			if text, ok := session.resolveConstants(value); ok {
+				if obj := NewDataObject(text); obj == nil {
+					return parseClipShapeProperty(obj)
+				}
+			}
+		}
+	}
+
+	return nil
+}
+
+// GetClip returns a View clipping area.
+// If the second argument (subviewID) is not specified or it is "" then a top position of the first argument (view) is returned
+func GetClip(view View, subviewID ...string) ClipShapeProperty {
+	if view = getSubview(view, subviewID); view != nil {
+		return getClipShapeProperty(view, Clip, view.Session())
+	}
+
+	return nil
+}
+
+// GetShapeOutside returns a shape around which adjacent inline content.
+// If the second argument (subviewID) is not specified or it is "" then a top position of the first argument (view) is returned
+func GetShapeOutside(view View, subviewID ...string) ClipShapeProperty {
+	if view = getSubview(view, subviewID); view != nil {
+		return getClipShapeProperty(view, ShapeOutside, view.Session())
+	}
+
+	return nil
+}

color.go

@@ -11,6 +11,22 @@ import (
 // Color - represent color in argb format
 type Color uint32
 
+// ARGB creates Color using alpha, red, green and blue components
+func ARGB[T int | uint | int8 | uint8](alpha, red, green, blue T) Color {
+	return ((Color(alpha) & 0xFF) << 24) +
+		((Color(red) & 0xFF) << 16) +
+		((Color(green) & 0xFF) << 8) +
+		(Color(blue) & 0xFF)
+}
+
+// RGB creates Color using red, green and blue components
+func RGB[T int | uint | int8 | uint8](red, green, blue T) Color {
+	return (Color(0xFF) << 24) +
+		((Color(red) & 0xFF) << 16) +
+		((Color(green) & 0xFF) << 8) +
+		(Color(blue) & 0xFF)
+}
+
 // ARGB - return alpha, red, green and blue components of the color
 func (color Color) ARGB() (uint8, uint8, uint8, uint8) {
 	return uint8(color >> 24),

colorConstants.go

@@ -2,6 +2,7 @@ package rui
 
 import "sort"
 
+// A set of predefined colors used in the library
 const (
 	// Black color constant
 	Black Color = 0xff000000
@@ -449,8 +450,12 @@ var colorConstants = map[string]Color{
 	"yellowgreen":          0xff9acd32,
 }
 
+// NamedColor make a relation between color and its name
 type NamedColor struct {
-	Name  string
+	// Name of a color
+	Name string
+
+	// Color value
 	Color Color
 }
 

colorPicker.go

@@ -4,20 +4,48 @@ import (
 	"strings"
 )
 
+// Constants for [ColorPicker] specific properties and events.
 const (
-	ColorChangedEvent = "color-changed"
-	ColorPickerValue  = "color-picker-value"
+	// ColorChangedEvent is the constant for "color-changed" property tag.
+	//
+	// Used by `ColorPicker`.
+	// Event generated when color picker value has been changed.
+	//
+	// General listener format:
+	//  func(picker rui.ColorPicker, newColor, oldColor rui.Color)
+	//
+	// where:
+	//   - picker - Interface of a color picker which generated this event,
+	//   - newColor - New color value,
+	//   - oldColor - Old color value.
+	//
+	// Allowed listener formats:
+	//  func(picker rui.ColorPicker, newColor rui.Color)
+	//  func(newColor, oldColor rui.Color)
+	//  func(newColor rui.Color)
+	//  func(picker rui.ColorPicker)
+	//  func()
+	ColorChangedEvent PropertyName = "color-changed"
+
+	// ColorPickerValue is the constant for "color-picker-value" property tag.
+	//
+	// Used by `ColorPicker`.
+	// Define current color picker value.
+	//
+	// Supported types: `Color`, `string`.
+	//
+	// Internal type is `Color`, other types converted to it during assignment.
+	// See `Color` description for more details.
+	ColorPickerValue PropertyName = "color-picker-value"
 )
 
-// ColorPicker - ColorPicker view
+// ColorPicker represent a ColorPicker view
 type ColorPicker interface {
 	View
 }
 
 type colorPickerData struct {
 	viewData
-	dataList
-	colorChangedListeners []func(ColorPicker, Color, Color)
 }
 
 // NewColorPicker create new ColorPicker object and return it
@@ -29,125 +57,69 @@ func NewColorPicker(session Session, params Params) ColorPicker {
 }
 
 func newColorPicker(session Session) View {
-	return NewColorPicker(session, nil)
+	return new(colorPickerData)
 }
 
 func (picker *colorPickerData) init(session Session) {
 	picker.viewData.init(session)
 	picker.tag = "ColorPicker"
 	picker.hasHtmlDisabled = true
-	picker.colorChangedListeners = []func(ColorPicker, Color, Color){}
 	picker.properties[Padding] = Px(0)
-	picker.dataListInit()
+	picker.normalize = normalizeColorPickerTag
+	picker.set = picker.setFunc
+	picker.changed = picker.propertyChanged
 }
 
-func (picker *colorPickerData) String() string {
-	return getViewString(picker, nil)
-}
-
-func (picker *colorPickerData) normalizeTag(tag string) string {
-	tag = strings.ToLower(tag)
+func normalizeColorPickerTag(tag PropertyName) PropertyName {
+	tag = defaultNormalize(tag)
 	switch tag {
 	case Value, ColorTag:
 		return ColorPickerValue
 	}
 
-	return picker.normalizeDataListTag(tag)
+	return normalizeDataListTag(tag)
 }
 
-func (picker *colorPickerData) Remove(tag string) {
-	picker.remove(picker.normalizeTag(tag))
-}
-
-func (picker *colorPickerData) remove(tag string) {
+func (picker *colorPickerData) setFunc(tag PropertyName, value any) []PropertyName {
 	switch tag {
 	case ColorChangedEvent:
-		if len(picker.colorChangedListeners) > 0 {
-			picker.colorChangedListeners = []func(ColorPicker, Color, Color){}
-			picker.propertyChangedEvent(tag)
-		}
+		return setTwoArgEventListener[ColorPicker, Color](picker, tag, value)
 
 	case ColorPickerValue:
 		oldColor := GetColorPickerValue(picker)
-		delete(picker.properties, ColorPickerValue)
-		picker.colorChanged(oldColor)
+		result := setColorProperty(picker, ColorPickerValue, value)
+		if result != nil {
+			picker.setRaw("old-color", oldColor)
+		}
+		return result
 
 	case DataList:
-		if len(picker.dataList.dataList) > 0 {
-			picker.setDataList(picker, []string{}, true)
-		}
-
-	default:
-		picker.viewData.remove(tag)
-	}
-}
-
-func (picker *colorPickerData) Set(tag string, value any) bool {
-	return picker.set(picker.normalizeTag(tag), value)
-}
-
-func (picker *colorPickerData) set(tag string, value any) bool {
-	if value == nil {
-		picker.remove(tag)
-		return true
+		return setDataList(picker, value, "")
 	}
 
+	return picker.viewData.setFunc(tag, value)
+}
+
+func (picker *colorPickerData) propertyChanged(tag PropertyName) {
 	switch tag {
-	case ColorChangedEvent:
-		listeners, ok := valueToEventWithOldListeners[ColorPicker, Color](value)
-		if !ok {
-			notCompatibleType(tag, value)
-			return false
-		} else if listeners == nil {
-			listeners = []func(ColorPicker, Color, Color){}
-		}
-		picker.colorChangedListeners = listeners
-		picker.propertyChangedEvent(tag)
-		return true
-
 	case ColorPickerValue:
-		oldColor := GetColorPickerValue(picker)
-		if picker.setColorProperty(ColorPickerValue, value) {
-			picker.colorChanged(oldColor)
-			return true
-		}
+		color := GetColorPickerValue(picker)
+		picker.Session().callFunc("setInputValue", picker.htmlID(), color.rgbString())
 
-	case DataList:
-		return picker.setDataList(picker, value, picker.created)
+		if listeners := GetColorChangedListeners(picker); len(listeners) > 0 {
+			oldColor := Color(0)
+			if value := picker.getRaw("old-color"); value != nil {
+				oldColor = value.(Color)
+			}
+			for _, listener := range listeners {
+				listener(picker, color, oldColor)
+			}
+		}
 
 	default:
-		return picker.viewData.set(tag, value)
+		picker.viewData.propertyChanged(tag)
 	}
-	return false
-}
 
-func (picker *colorPickerData) colorChanged(oldColor Color) {
-	if newColor := GetColorPickerValue(picker); oldColor != newColor {
-		if picker.created {
-			picker.session.callFunc("setInputValue", picker.htmlID(), newColor.rgbString())
-		}
-		for _, listener := range picker.colorChangedListeners {
-			listener(picker, newColor, oldColor)
-		}
-		picker.propertyChangedEvent(ColorTag)
-	}
-}
-
-func (picker *colorPickerData) Get(tag string) any {
-	return picker.get(picker.normalizeTag(tag))
-}
-
-func (picker *colorPickerData) get(tag string) any {
-	switch tag {
-	case ColorChangedEvent:
-		return picker.colorChangedListeners
-
-	case DataList:
-		return picker.dataList.dataList
-
-	default:
-		return picker.viewData.get(tag)
-	}
 }
 
 func (picker *colorPickerData) htmlTag() string {
@@ -155,7 +127,10 @@ func (picker *colorPickerData) htmlTag() string {
 }
 
 func (picker *colorPickerData) htmlSubviews(self View, buffer *strings.Builder) {
-	picker.dataListHtmlSubviews(self, buffer)
+	dataListHtmlSubviews(self, buffer, func(text string, session Session) string {
+		text, _ = session.resolveConstants(text)
+		return text
+	})
 }
 
 func (picker *colorPickerData) htmlProperties(self View, buffer *strings.Builder) {
@@ -170,20 +145,23 @@ func (picker *colorPickerData) htmlProperties(self View, buffer *strings.Builder
 		buffer.WriteString(` onclick="stopEventPropagation(this, event)"`)
 	}
 
-	picker.dataListHtmlProperties(picker, buffer)
+	dataListHtmlProperties(picker, buffer)
 }
 
-func (picker *colorPickerData) handleCommand(self View, command string, data DataObject) bool {
+func (picker *colorPickerData) handleCommand(self View, command PropertyName, data DataObject) bool {
 	switch command {
 	case "textChanged":
 		if text, ok := data.PropertyValue("text"); ok {
-			oldColor := GetColorPickerValue(picker)
 			if color, ok := StringToColor(text); ok {
+				oldColor := GetColorPickerValue(picker)
 				picker.properties[ColorPickerValue] = color
 				if color != oldColor {
-					for _, listener := range picker.colorChangedListeners {
+					for _, listener := range GetColorChangedListeners(picker) {
 						listener(picker, color, oldColor)
 					}
+					if listener, ok := picker.changeListener[ColorPickerValue]; ok {
+						listener(picker, ColorPickerValue)
+					}
 				}
 			}
 		}
@@ -196,14 +174,11 @@ func (picker *colorPickerData) handleCommand(self View, command string, data Dat
 // GetColorPickerValue returns the value of ColorPicker subview.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetColorPickerValue(view View, subviewID ...string) Color {
-	if len(subviewID) > 0 && subviewID[0] != "" {
-		view = ViewByID(view, subviewID[0])
-	}
-	if view != nil {
+	if view = getSubview(view, subviewID); view != nil {
 		if value, ok := colorProperty(view, ColorPickerValue, view.Session()); ok {
 			return value
 		}
-		for _, tag := range []string{ColorPickerValue, Value, ColorTag} {
+		for _, tag := range []PropertyName{ColorPickerValue, Value, ColorTag} {
 			if value := valueFromStyle(view, tag); value != nil {
 				if result, ok := valueToColor(value, view.Session()); ok {
 					return result
@@ -218,5 +193,5 @@ func GetColorPickerValue(view View, subviewID ...string) Color {
 // If there are no listeners then the empty list is returned
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetColorChangedListeners(view View, subviewID ...string) []func(ColorPicker, Color, Color) {
-	return getEventWithOldListeners[ColorPicker, Color](view, subviewID, ColorChangedEvent)
+	return getTwoArgEventListeners[ColorPicker, Color](view, subviewID, ColorChangedEvent)
 }

columnLayout.go

@@ -2,57 +2,120 @@ package rui
 
 import (
 	"strconv"
-	"strings"
 )
 
+// Constants for [ColumnLayout] specific properties and events
 const (
-	// ColumnCount is the constant for the "column-count" property tag.
-	// The "column-count" int property specifies number of columns into which the content is break
-	// Values less than zero are not valid. if the "column-count" property value is 0 then
-	// the number of columns is calculated based on the "column-width" property
-	ColumnCount = "column-count"
+	// ColumnCount is the constant for "column-count" property tag.
+	//
+	// Used by ColumnLayout.
+	// Specifies number of columns into which the content is break. Values less than zero are not valid. If this property
+	// value is 0 then the number of columns is calculated based on the "column-width" property.
+	//
+	// Supported types: int, string.
+	//
+	// Values:
+	//   - 0 or "0" - Use "column-width" to control how many columns will be created.
+	//   - positive value - Тhe number of columns into which the content is divided.
+	ColumnCount PropertyName = "column-count"
 
-	// ColumnWidth is the constant for the "column-width" property tag.
-	// The "column-width" SizeUnit property specifies the width of each column.
-	ColumnWidth = "column-width"
+	// ColumnWidth is the constant for "column-width" property tag.
+	//
+	// Used by ColumnLayout.
+	// Specifies the width of each column.
+	//
+	// Supported types: SizeUnit, SizeFunc, string, float, int.
+	//
+	// Internal type is SizeUnit, other types converted to it during assignment.
+	// See [SizeUnit] description for more details.
+	ColumnWidth PropertyName = "column-width"
 
-	// ColumnGap is the constant for the "column-gap" property tag.
-	// The "column-width" SizeUnit property sets the size of the gap (gutter) between columns.
-	ColumnGap = "column-gap"
+	// ColumnGap is the constant for "column-gap" property tag.
+	//
+	// Used by ColumnLayout.
+	// Set the size of the gap (gutter) between columns.
+	//
+	// Supported types: SizeUnit, SizeFunc, string, float, int.
+	//
+	// Internal type is SizeUnit, other types converted to it during assignment.
+	// See [SizeUnit] description for more details.
+	ColumnGap PropertyName = "column-gap"
 
-	// ColumnSeparator is the constant for the "column-separator" property tag.
-	// The "column-separator" property specifies the line drawn between columns in a multi-column layout.
-	ColumnSeparator = "column-separator"
+	// ColumnSeparator is the constant for "column-separator" property tag.
+	//
+	// Used by ColumnLayout.
+	// Specifies the line drawn between columns in a multi-column layout.
+	//
+	// Supported types: ColumnSeparatorProperty, ViewBorder.
+	//
+	// Internal type is ColumnSeparatorProperty, other types converted to it during assignment.
+	// See [ColumnSeparatorProperty] and [ViewBorder] description for more details.
+	ColumnSeparator PropertyName = "column-separator"
 
-	// ColumnSeparatorStyle is the constant for the "column-separator-style" property tag.
-	// The "column-separator-style" int property sets the style of the line drawn between
-	// columns in a multi-column layout.
-	// Valid values are NoneLine (0), SolidLine (1), DashedLine (2), DottedLine (3), and DoubleLine (4).
-	ColumnSeparatorStyle = "column-separator-style"
+	// ColumnSeparatorStyle is the constant for "column-separator-style" property tag.
+	//
+	// Used by ColumnLayout.
+	// Controls the style of the line drawn between columns in a multi-column layout.
+	//
+	// Supported types: int, string.
+	//
+	// Values:
+	//   - 0 (NoneLine) or "none" - The separator will not be drawn.
+	//   - 1 (SolidLine) or "solid" - Solid line as a separator.
+	//   - 2 (DashedLine) or "dashed" - Dashed line as a separator.
+	//   - 3 (DottedLine) or "dotted" - Dotted line as a separator.
+	//   - 4 (DoubleLine) or "double" - Double line as a separator.
+	ColumnSeparatorStyle PropertyName = "column-separator-style"
 
-	// ColumnSeparatorWidth is the constant for the "column-separator-width" property tag.
-	// The "column-separator-width" SizeUnit property sets the width of the line drawn between
-	// columns in a multi-column layout.
-	ColumnSeparatorWidth = "column-separator-width"
+	// ColumnSeparatorWidth is the constant for "column-separator-width" property tag.
+	//
+	// Used by ColumnLayout.
+	// Set the width of the line drawn between columns in a multi-column layout.
+	//
+	// Supported types: SizeUnit, SizeFunc, string, float, int.
+	//
+	// Internal type is SizeUnit, other types converted to it during assignment.
+	// See SizeUnit description for more details.
+	ColumnSeparatorWidth PropertyName = "column-separator-width"
 
-	// ColumnSeparatorColor is the constant for the "column-separator-color" property tag.
-	// The "column-separator-color" Color property sets the color of the line drawn between
-	// columns in a multi-column layout.
-	ColumnSeparatorColor = "column-separator-color"
+	// ColumnSeparatorColor is the constant for "column-separator-color" property tag.
+	//
+	// Used by ColumnLayout.
+	// Set the color of the line drawn between columns in a multi-column layout.
+	//
+	// Supported types: Color, string.
+	//
+	// Internal type is Color, other types converted to it during assignment.
+	// See Color description for more details.
+	ColumnSeparatorColor PropertyName = "column-separator-color"
 
-	// ColumnFill is the constant for the "column-fill" property tag.
-	// The "column-fill" int property controls how an ColumnLayout's contents are balanced when broken into columns.
-	// Valid values are
-	// * ColumnFillBalance (0) - Content is equally divided between columns (default value);
-	// * ColumnFillAuto (1) - Columns are filled sequentially. Content takes up only the room it needs, possibly resulting in some columns remaining empty.
-	ColumnFill = "column-fill"
+	// ColumnFill is the constant for "column-fill" property tag.
+	//
+	// Used by ColumnLayout.
+	// Controls how a ColumnLayout's content is balanced when broken into columns. Default value is "balance".
+	//
+	// Supported types: int, string.
+	//
+	// Values:
+	//   - 0 (ColumnFillBalance) or "balance" - Content is equally divided between columns.
+	//   - 1 (ColumnFillAuto) or "auto" - Columns are filled sequentially. Content takes up only the room it needs, possibly resulting in some columns remaining empty.
+	ColumnFill PropertyName = "column-fill"
 
-	// ColumnSpanAll is the constant for the "column-span-all" property tag.
-	// The "column-span-all" bool property makes it possible for a view to span across all columns when its value is set to true.
-	ColumnSpanAll = "column-span-all"
+	// ColumnSpanAll is the constant for "column-span-all" property tag.
+	//
+	// Used by ColumnLayout.
+	// Property used in views placed inside the column layout container. Makes it possible for a view to span across all
+	// columns. Default value is false.
+	//
+	// Supported types: bool, int, string.
+	//
+	// Values:
+	//   - true, 1, "true", "yes", "on", or  "1" - View will span across all columns.
+	//   - false, 0, "false", "no", "off", or "0" - View will be a part of a column.
+	ColumnSpanAll PropertyName = "column-span-all"
 )
 
-// ColumnLayout - grid-container of View
+// ColumnLayout represent a ColumnLayout view
 type ColumnLayout interface {
 	ViewsContainer
 }
@@ -70,22 +133,20 @@ func NewColumnLayout(session Session, params Params) ColumnLayout {
 }
 
 func newColumnLayout(session Session) View {
-	return NewColumnLayout(session, nil)
+	return new(columnLayoutData)
 }
 
 // Init initialize fields of ColumnLayout by default values
-func (ColumnLayout *columnLayoutData) init(session Session) {
-	ColumnLayout.viewsContainerData.init(session)
-	ColumnLayout.tag = "ColumnLayout"
-	//ColumnLayout.systemClass = "ruiColumnLayout"
+func (columnLayout *columnLayoutData) init(session Session) {
+	columnLayout.viewsContainerData.init(session)
+	columnLayout.tag = "ColumnLayout"
+	columnLayout.systemClass = "ruiColumnLayout"
+	columnLayout.normalize = normalizeColumnLayoutTag
+	columnLayout.changed = columnLayout.propertyChanged
 }
 
-func (columnLayout *columnLayoutData) String() string {
-	return getViewString(columnLayout, nil)
-}
-
-func (columnLayout *columnLayoutData) normalizeTag(tag string) string {
-	tag = strings.ToLower(tag)
+func normalizeColumnLayoutTag(tag PropertyName) PropertyName {
+	tag = defaultNormalize(tag)
 	switch tag {
 	case Gap:
 		return ColumnGap
@@ -93,62 +154,28 @@ func (columnLayout *columnLayoutData) normalizeTag(tag string) string {
 	return tag
 }
 
-func (columnLayout *columnLayoutData) Get(tag string) any {
-	return columnLayout.get(columnLayout.normalizeTag(tag))
-}
-
-func (columnLayout *columnLayoutData) Remove(tag string) {
-	columnLayout.remove(columnLayout.normalizeTag(tag))
-}
-
-func (columnLayout *columnLayoutData) remove(tag string) {
-	columnLayout.viewsContainerData.remove(tag)
-	if columnLayout.created {
-		switch tag {
-		case ColumnCount, ColumnWidth, ColumnGap:
-			columnLayout.session.updateCSSProperty(columnLayout.htmlID(), tag, "")
-
-		case ColumnSeparator:
-			columnLayout.session.updateCSSProperty(columnLayout.htmlID(), "column-rule", "")
+func (columnLayout *columnLayoutData) propertyChanged(tag PropertyName) {
+	switch tag {
+	case ColumnSeparator:
+		css := ""
+		session := columnLayout.Session()
+		if value := columnLayout.getRaw(ColumnSeparator); value != nil {
+			separator := value.(ColumnSeparatorProperty)
+			css = separator.cssValue(session)
 		}
-	}
-}
+		session.updateCSSProperty(columnLayout.htmlID(), "column-rule", css)
 
-func (columnLayout *columnLayoutData) Set(tag string, value any) bool {
-	return columnLayout.set(columnLayout.normalizeTag(tag), value)
-}
-
-func (columnLayout *columnLayoutData) set(tag string, value any) bool {
-	if value == nil {
-		columnLayout.remove(tag)
-		return true
-	}
-
-	if !columnLayout.viewsContainerData.set(tag, value) {
-		return false
-	}
-
-	if columnLayout.created {
-		switch tag {
-		case ColumnSeparator:
-			css := ""
-			session := columnLayout.Session()
-			if val, ok := columnLayout.properties[ColumnSeparator]; ok {
-				separator := val.(ColumnSeparatorProperty)
-				css = separator.cssValue(columnLayout.Session())
-			}
-			session.updateCSSProperty(columnLayout.htmlID(), "column-rule", css)
-
-		case ColumnCount:
-			session := columnLayout.Session()
-			if count, ok := intProperty(columnLayout, tag, session, 0); ok && count > 0 {
-				session.updateCSSProperty(columnLayout.htmlID(), tag, strconv.Itoa(count))
-			} else {
-				session.updateCSSProperty(columnLayout.htmlID(), tag, "auto")
-			}
+	case ColumnCount:
+		session := columnLayout.Session()
+		if count := GetColumnCount(columnLayout); count > 0 {
+			session.updateCSSProperty(columnLayout.htmlID(), string(ColumnCount), strconv.Itoa(count))
+		} else {
+			session.updateCSSProperty(columnLayout.htmlID(), string(ColumnCount), "auto")
 		}
+
+	default:
+		columnLayout.viewsContainerData.propertyChanged(tag)
 	}
-	return true
 }
 
 // GetColumnCount returns int value which specifies number of columns into which the content of
@@ -172,11 +199,7 @@ func GetColumnGap(view View, subviewID ...string) SizeUnit {
 }
 
 func getColumnSeparator(view View, subviewID []string) ViewBorder {
-	if len(subviewID) > 0 && subviewID[0] != "" {
-		view = ViewByID(view, subviewID[0])
-	}
-
-	if view != nil {
+	if view = getSubview(view, subviewID); view != nil {
 		value := view.Get(ColumnSeparator)
 		if value == nil {
 			value = valueFromStyle(view, ColumnSeparator)

columnSeparator.go

@@ -10,19 +10,22 @@ type ColumnSeparatorProperty interface {
 	Properties
 	fmt.Stringer
 	stringWriter
+
+	// ViewBorder returns column separator description in a form of ViewBorder
 	ViewBorder(session Session) ViewBorder
+
 	cssValue(session Session) string
 }
 
 type columnSeparatorProperty struct {
-	propertyList
+	dataProperty
 }
 
 func newColumnSeparatorProperty(value any) ColumnSeparatorProperty {
 
 	if value == nil {
 		separator := new(columnSeparatorProperty)
-		separator.properties = map[string]any{}
+		separator.init()
 		return separator
 	}
 
@@ -32,17 +35,18 @@ func newColumnSeparatorProperty(value any) ColumnSeparatorProperty {
 
 	case DataObject:
 		separator := new(columnSeparatorProperty)
-		separator.properties = map[string]any{}
-		for _, tag := range []string{Style, Width, ColorTag} {
-			if val, ok := value.PropertyValue(tag); ok && val != "" {
-				separator.set(tag, value)
+		separator.init()
+		for _, tag := range []PropertyName{Style, Width, ColorTag} {
+			if val, ok := value.PropertyValue(string(tag)); ok && val != "" {
+				propertiesSet(separator, tag, value)
 			}
 		}
 		return separator
 
 	case ViewBorder:
 		separator := new(columnSeparatorProperty)
-		separator.properties = map[string]any{
+		separator.init()
+		separator.properties = map[PropertyName]any{
 			Style:    value.Style,
 			Width:    value.Width,
 			ColorTag: value.Color,
@@ -54,12 +58,17 @@ func newColumnSeparatorProperty(value any) ColumnSeparatorProperty {
 	return nil
 }
 
-// NewColumnSeparator creates the new ColumnSeparatorProperty
-func NewColumnSeparator(params Params) ColumnSeparatorProperty {
+// NewColumnSeparatorProperty creates the new ColumnSeparatorProperty.
+//
+// The following properties can be used:
+//   - "style" (Style) - Determines the line style (type is int). Valid values: 0 (NoneLine), 1 (SolidLine), 2 (DashedLine), 3 (DottedLine), or 4 (DoubleLine);
+//   - "color" (ColorTag) - Determines the line color (type is [Color]);
+//   - "width" (Width) - Determines the line thickness (type is [SizeUnit]).
+func NewColumnSeparatorProperty(params Params) ColumnSeparatorProperty {
 	separator := new(columnSeparatorProperty)
-	separator.properties = map[string]any{}
+	separator.init()
 	if params != nil {
-		for _, tag := range []string{Style, Width, ColorTag} {
+		for _, tag := range []PropertyName{Style, Width, ColorTag} {
 			if value, ok := params[tag]; ok && value != nil {
 				separator.Set(tag, value)
 			}
@@ -68,8 +77,29 @@ func NewColumnSeparator(params Params) ColumnSeparatorProperty {
 	return separator
 }
 
-func (separator *columnSeparatorProperty) normalizeTag(tag string) string {
-	tag = strings.ToLower(tag)
+// NewColumnSeparator creates the new ColumnSeparatorProperty.
+//
+// Arguments:
+//   - style - determines the line style. Valid values: 0 [NoneLine], 1 [SolidLine], 2 [DashedLine], 3 [DottedLine], or 4 [DoubleLine];
+//   - color - determines the line color;
+//   - width - determines the line thickness.
+func NewColumnSeparator(style int, color Color, width SizeUnit) ColumnSeparatorProperty {
+	return NewColumnSeparatorProperty(Params{
+		Width:    width,
+		Style:    style,
+		ColorTag: color,
+	})
+}
+
+func (separator *columnSeparatorProperty) init() {
+	separator.dataProperty.init()
+	separator.normalize = normalizeVolumnSeparatorTag
+	separator.set = columnSeparatorSet
+	separator.supportedProperties = []PropertyName{Style, Width, ColorTag}
+}
+
+func normalizeVolumnSeparatorTag(tag PropertyName) PropertyName {
+	tag = defaultNormalize(tag)
 	switch tag {
 	case ColumnSeparatorStyle, "separator-style":
 		return Style
@@ -87,12 +117,12 @@ func (separator *columnSeparatorProperty) normalizeTag(tag string) string {
 func (separator *columnSeparatorProperty) writeString(buffer *strings.Builder, indent string) {
 	buffer.WriteString("_{ ")
 	comma := false
-	for _, tag := range []string{Style, Width, ColorTag} {
+	for _, tag := range []PropertyName{Style, Width, ColorTag} {
 		if value, ok := separator.properties[tag]; ok {
 			if comma {
 				buffer.WriteString(", ")
 			}
-			buffer.WriteString(tag)
+			buffer.WriteString(string(tag))
 			buffer.WriteString(" = ")
 			writePropertyValue(buffer, BorderStyle, value, indent)
 			comma = true
@@ -106,47 +136,12 @@ func (separator *columnSeparatorProperty) String() string {
 	return runStringWriter(separator)
 }
 
-func (separator *columnSeparatorProperty) Remove(tag string) {
-
-	switch tag = separator.normalizeTag(tag); tag {
-	case Style, Width, ColorTag:
-		delete(separator.properties, tag)
-
-	default:
-		ErrorLogF(`"%s" property is not compatible with the ColumnSeparatorProperty`, tag)
+func getColumnSeparatorProperty(properties Properties) ColumnSeparatorProperty {
+	if val := properties.getRaw(ColumnSeparator); val != nil {
+		if separator, ok := val.(ColumnSeparatorProperty); ok {
+			return separator
+		}
 	}
-}
-
-func (separator *columnSeparatorProperty) Set(tag string, value any) bool {
-	tag = separator.normalizeTag(tag)
-
-	if value == nil {
-		separator.remove(tag)
-		return true
-	}
-
-	switch tag {
-	case Style:
-		return separator.setEnumProperty(Style, value, enumProperties[BorderStyle].values)
-
-	case Width:
-		return separator.setSizeProperty(Width, value)
-
-	case ColorTag:
-		return separator.setColorProperty(ColorTag, value)
-	}
-
-	ErrorLogF(`"%s" property is not compatible with the ColumnSeparatorProperty`, tag)
-	return false
-}
-
-func (separator *columnSeparatorProperty) Get(tag string) any {
-	tag = separator.normalizeTag(tag)
-
-	if result, ok := separator.properties[tag]; ok {
-		return result
-	}
-
 	return nil
 }
 
@@ -189,3 +184,10 @@ func (separator *columnSeparatorProperty) cssValue(session Session) string {
 
 	return buffer.String()
 }
+
+func columnSeparatorSet(properties Properties, tag PropertyName, value any) []PropertyName {
+	if tag == Style {
+		return setEnumProperty(properties, Style, value, enumProperties[BorderStyle].values)
+	}
+	return propertiesSet(properties, tag, value)
+}

cssBuilder.go

@@ -150,9 +150,11 @@ func (builder *cssValueBuilder) addValues(key, separator string, values ...strin
 	}
 }
 
-func (builder *cssStyleBuilder) init() {
+func (builder *cssStyleBuilder) init(kbSize int) {
 	builder.buffer = allocStringBuilder()
-	builder.buffer.Grow(16 * 1024)
+	if kbSize > 0 {
+		builder.buffer.Grow(kbSize * 1024)
+	}
 }
 
 func (builder *cssStyleBuilder) finish() string {
@@ -168,7 +170,7 @@ func (builder *cssStyleBuilder) finish() string {
 
 func (builder *cssStyleBuilder) startMedia(rule string) {
 	if builder.buffer == nil {
-		builder.init()
+		builder.init(0)
 	}
 	builder.buffer.WriteString(`@media screen`)
 	builder.buffer.WriteString(rule)
@@ -178,7 +180,7 @@ func (builder *cssStyleBuilder) startMedia(rule string) {
 
 func (builder *cssStyleBuilder) endMedia() {
 	if builder.buffer == nil {
-		builder.init()
+		builder.init(0)
 	}
 	builder.buffer.WriteString(`}\n`)
 	builder.media = false
@@ -192,7 +194,7 @@ func (builder *cssStyleBuilder) startStyle(name string) {
 	}
 
 	if builder.buffer == nil {
-		builder.init()
+		builder.init(0)
 	}
 	if builder.media {
 		builder.buffer.WriteString(`\t`)
@@ -210,7 +212,7 @@ func (builder *cssStyleBuilder) startStyle(name string) {
 
 func (builder *cssStyleBuilder) endStyle() {
 	if builder.buffer == nil {
-		builder.init()
+		builder.init(0)
 	}
 	if builder.media {
 		builder.buffer.WriteString(`\t`)
@@ -220,7 +222,7 @@ func (builder *cssStyleBuilder) endStyle() {
 
 func (builder *cssStyleBuilder) startAnimation(name string) {
 	if builder.buffer == nil {
-		builder.init()
+		builder.init(0)
 	}
 
 	builder.media = true
@@ -231,7 +233,7 @@ func (builder *cssStyleBuilder) startAnimation(name string) {
 
 func (builder *cssStyleBuilder) endAnimation() {
 	if builder.buffer == nil {
-		builder.init()
+		builder.init(0)
 	}
 	builder.buffer.WriteString(`}\n`)
 	builder.media = false
@@ -239,7 +241,7 @@ func (builder *cssStyleBuilder) endAnimation() {
 
 func (builder *cssStyleBuilder) startAnimationFrame(name string) {
 	if builder.buffer == nil {
-		builder.init()
+		builder.init(0)
 	}
 
 	builder.buffer.WriteString(`\t`)
@@ -249,7 +251,7 @@ func (builder *cssStyleBuilder) startAnimationFrame(name string) {
 
 func (builder *cssStyleBuilder) endAnimationFrame() {
 	if builder.buffer == nil {
-		builder.init()
+		builder.init(0)
 	}
 	builder.buffer.WriteString(`\t}\n`)
 }
@@ -257,7 +259,7 @@ func (builder *cssStyleBuilder) endAnimationFrame() {
 func (builder *cssStyleBuilder) add(key, value string) {
 	if value != "" {
 		if builder.buffer == nil {
-			builder.init()
+			builder.init(0)
 		}
 		if builder.media {
 			builder.buffer.WriteString(`\t`)
@@ -276,7 +278,7 @@ func (builder *cssStyleBuilder) addValues(key, separator string, values ...strin
 	}
 
 	if builder.buffer == nil {
-		builder.init()
+		builder.init(0)
 	}
 	if builder.media {
 		builder.buffer.WriteString(`\t`)

customView.go

@@ -5,8 +5,13 @@ import "strings"
 // CustomView defines a custom view interface
 type CustomView interface {
 	ViewsContainer
+
+	// CreateSuperView must be implemented to create a base view from which custom control has been built
 	CreateSuperView(session Session) View
+
+	// SuperView must be implemented to return a base view from which custom control has been built
 	SuperView() View
+
 	setSuperView(view View)
 	setTag(tag string)
 }
@@ -31,6 +36,9 @@ func InitCustomView(customView CustomView, tag string, session Session, params P
 	return true
 }
 
+func (customView *CustomViewData) init(session Session) {
+}
+
 // SuperView returns a super view
 func (customView *CustomViewData) SuperView() View {
 	return customView.superView
@@ -52,43 +60,62 @@ func (customView *CustomViewData) setTag(tag string) {
 
 // Get returns a value of the property with name defined by the argument.
 // The type of return value depends on the property. If the property is not set then nil is returned.
-func (customView *CustomViewData) Get(tag string) any {
+func (customView *CustomViewData) Get(tag PropertyName) any {
 	return customView.superView.Get(tag)
 }
 
-func (customView *CustomViewData) getRaw(tag string) any {
+func (customView *CustomViewData) getRaw(tag PropertyName) any {
 	return customView.superView.getRaw(tag)
 }
 
-func (customView *CustomViewData) setRaw(tag string, value any) {
+func (customView *CustomViewData) setRaw(tag PropertyName, value any) {
 	customView.superView.setRaw(tag, value)
 }
 
+func (customView *CustomViewData) setContent(value any) bool {
+	if container, ok := customView.superView.(ViewsContainer); ok {
+		return container.setContent(value)
+	}
+	return false
+}
+
 // Set sets the value (second argument) of the property with name defined by the first argument.
 // Return "true" if the value has been set, in the opposite case "false" are returned and
 // a description of the error is written to the log
-func (customView *CustomViewData) Set(tag string, value any) bool {
+func (customView *CustomViewData) Set(tag PropertyName, value any) bool {
 	return customView.superView.Set(tag, value)
 }
 
-func (customView *CustomViewData) SetAnimated(tag string, value any, animation Animation) bool {
+// SetAnimated sets the value (second argument) of the property with name defined by the first argument.
+// Return "true" if the value has been set, in the opposite case "false" are returned and
+// a description of the error is written to the log
+func (customView *CustomViewData) SetAnimated(tag PropertyName, value any, animation AnimationProperty) bool {
 	return customView.superView.SetAnimated(tag, value, animation)
 }
 
-func (customView *CustomViewData) SetChangeListener(tag string, listener func(View, string)) {
+func (customView *CustomViewData) SetParams(params Params) bool {
+	return customView.superView.SetParams(params)
+}
+
+// SetChangeListener set the function to track the change of the View property
+func (customView *CustomViewData) SetChangeListener(tag PropertyName, listener func(View, PropertyName)) {
 	customView.superView.SetChangeListener(tag, listener)
 }
 
 // Remove removes the property with name defined by the argument
-func (customView *CustomViewData) Remove(tag string) {
+func (customView *CustomViewData) Remove(tag PropertyName) {
 	customView.superView.Remove(tag)
 }
 
 // AllTags returns an array of the set properties
-func (customView *CustomViewData) AllTags() []string {
+func (customView *CustomViewData) AllTags() []PropertyName {
 	return customView.superView.AllTags()
 }
 
+func (customView *CustomViewData) empty() bool {
+	return customView.superView.empty()
+}
+
 // Clear removes all properties
 func (customView *CustomViewData) Clear() {
 	customView.superView.Clear()
@@ -151,10 +178,12 @@ func (customView *CustomViewData) Frame() Frame {
 	return customView.superView.Frame()
 }
 
+// Scroll returns a location and size of a scrollable view in pixels
 func (customView *CustomViewData) Scroll() Frame {
 	return customView.superView.Scroll()
 }
 
+// HasFocus returns "true" if the view has focus
 func (customView *CustomViewData) HasFocus() bool {
 	return customView.superView.HasFocus()
 }
@@ -167,7 +196,7 @@ func (customView *CustomViewData) onItemResize(self View, index string, x, y, wi
 	customView.superView.onItemResize(customView.superView, index, x, y, width, height)
 }
 
-func (customView *CustomViewData) handleCommand(self View, command string, data DataObject) bool {
+func (customView *CustomViewData) handleCommand(self View, command PropertyName, data DataObject) bool {
 	return customView.superView.handleCommand(customView.superView, command, data)
 }
 
@@ -195,6 +224,10 @@ func (customView *CustomViewData) htmlProperties(self View, buffer *strings.Buil
 	customView.superView.htmlProperties(customView.superView, buffer)
 }
 
+func (customView *CustomViewData) htmlDisabledProperty() bool {
+	return customView.superView.htmlDisabledProperty()
+}
+
 func (customView *CustomViewData) cssStyle(self View, builder cssBuilder) {
 	customView.superView.cssStyle(customView.superView, builder)
 }
@@ -259,9 +292,9 @@ func (customView *CustomViewData) ViewIndex(view View) int {
 	return -1
 }
 
-func (customView *CustomViewData) exscludeTags() []string {
+func (customView *CustomViewData) exscludeTags() []PropertyName {
 	if customView.superView != nil {
-		exsclude := []string{}
+		exsclude := []PropertyName{}
 		for tag, value := range customView.defaultParams {
 			if value == customView.superView.getRaw(tag) {
 				exsclude = append(exsclude, tag)
@@ -272,9 +305,13 @@ func (customView *CustomViewData) exscludeTags() []string {
 	return nil
 }
 
+// String convert internal representation of a [CustomViewData] into a string.
 func (customView *CustomViewData) String() string {
 	if customView.superView != nil {
-		return getViewString(customView, customView.exscludeTags())
+		buffer := allocStringBuilder()
+		defer freeStringBuilder(buffer)
+		writeViewStyle(customView.tag, customView, buffer, "", customView.exscludeTags())
+		return buffer.String()
 	}
 	return customView.tag + " { }"
 }
@@ -285,21 +322,26 @@ func (customView *CustomViewData) setScroll(x, y, width, height float64) {
 	}
 }
 
-func (customView *CustomViewData) Transition(tag string) Animation {
+// Transition returns the transition animation of the property(tag). Returns nil is there is no transition animation.
+func (customView *CustomViewData) Transition(tag PropertyName) AnimationProperty {
 	if customView.superView != nil {
 		return customView.superView.Transition(tag)
 	}
 	return nil
 }
 
-func (customView *CustomViewData) Transitions() map[string]Animation {
+// Transitions returns a map of transition animations. The result is always non-nil.
+func (customView *CustomViewData) Transitions() map[PropertyName]AnimationProperty {
 	if customView.superView != nil {
 		return customView.superView.Transitions()
 	}
-	return map[string]Animation{}
+	return map[PropertyName]AnimationProperty{}
 }
 
-func (customView *CustomViewData) SetTransition(tag string, animation Animation) {
+// SetTransition sets the transition animation for the property if "animation" argument is not nil, and
+// removes the transition animation of the property if "animation" argument  is nil.
+// The "tag" argument is the property name.
+func (customView *CustomViewData) SetTransition(tag PropertyName, animation AnimationProperty) {
 	if customView.superView != nil {
 		customView.superView.SetTransition(tag, animation)
 	}

data.go

@@ -7,25 +7,49 @@ import (
 
 // DataValue interface of a data node value
 type DataValue interface {
+	// IsObject returns "true" if data value is an object
 	IsObject() bool
+
+	// Object returns data value as a data object
 	Object() DataObject
+
+	// Value returns value as a string
 	Value() string
 }
 
 // DataObject interface of a data object
 type DataObject interface {
 	DataValue
+
+	// Tag returns data object tag
 	Tag() string
+
+	// PropertyCount returns properties count
 	PropertyCount() int
+
+	// Property returns a data node corresponding to a property with specific index
 	Property(index int) DataNode
+
+	// PropertyByTag returns a data node corresponding to a property tag
 	PropertyByTag(tag string) DataNode
+
+	// PropertyValue returns a string value of a property with a specific tag
 	PropertyValue(tag string) (string, bool)
+
+	// PropertyObject returns an object value of a property with a specific tag
 	PropertyObject(tag string) DataObject
+
+	// SetPropertyValue sets a string value of a property with a specific tag
 	SetPropertyValue(tag, value string)
+
+	// SetPropertyObject sets an object value of a property with a specific tag
 	SetPropertyObject(tag string, object DataObject)
+
+	// ToParams create a params(map) representation of a data object
 	ToParams() Params
 }
 
+// Constants which are used to describe a node type, see [DataNode]
 const (
 	// TextNode - node is the pair "tag - text value". Syntax: <tag> = <text>
 	TextNode = 0
@@ -37,13 +61,28 @@ const (
 
 // DataNode interface of a data node
 type DataNode interface {
+	// Tag returns a tag name
 	Tag() string
+
+	// Type returns a node type. Possible values are TextNode, ObjectNode and ArrayNode
 	Type() int
+
+	// Text returns node text
 	Text() string
+
+	// Object returns node as object if that node type is an object
 	Object() DataObject
+
+	// ArraySize returns array size if that node type is an array
 	ArraySize() int
+
+	// ArrayElement returns a value of an array if that node type is an array
 	ArrayElement(index int) DataValue
+
+	// ArrayElements returns an array of objects if that node is an array
 	ArrayElements() []DataValue
+
+	// ArrayAsParams returns an array of a params(map) if that node is an array
 	ArrayAsParams() []Params
 }
 
@@ -134,7 +173,7 @@ func (object *dataObject) PropertyObject(tag string) DataObject {
 }
 
 func (object *dataObject) setNode(node DataNode) {
-	if object.property == nil || len(object.property) == 0 {
+	if len(object.property) == 0 {
 		object.property = []DataNode{node}
 	} else {
 		tag := node.Tag()
@@ -173,12 +212,12 @@ func (object *dataObject) ToParams() Params {
 		switch node.Type() {
 		case TextNode:
 			if text := node.Text(); text != "" {
-				params[node.Tag()] = text
+				params[PropertyName(node.Tag())] = text
 			}
 
 		case ObjectNode:
 			if obj := node.Object(); obj != nil {
-				params[node.Tag()] = node.Object()
+				params[PropertyName(node.Tag())] = node.Object()
 			}
 
 		case ArrayNode:
@@ -195,7 +234,7 @@ func (object *dataObject) ToParams() Params {
 				}
 			}
 			if len(array) > 0 {
-				params[node.Tag()] = array
+				params[PropertyName(node.Tag())] = array
 			}
 		}
 	}

dataList.go

@@ -1,26 +1,105 @@
 package rui
 
-import "strings"
-
-const (
-	// DataList is the constant for the "data-list" property tag.
-	DataList = "data-list"
+import (
+	"fmt"
+	"strconv"
+	"strings"
+	"time"
 )
 
-type dataList struct {
-	dataList     []string
-	dataListHtml bool
-}
+const (
+	// DataList is the constant for "data-list" property tag.
+	//
+	// Used by ColorPicker, DatePicker, EditView, NumberPicker, TimePicker.
+	//
+	// # Usage in ColorPicker
+	//
+	// List of pre-defined colors.
+	//
+	// Supported types: []string, string, []fmt.Stringer, []Color, []any containing
+	// elements of string, fmt.Stringer, int, int8…int64, uint, uint8…uint64.
+	//
+	// Internal type is []string, other types converted to it during assignment.
+	//
+	// Conversion rules:
+	//   - string - contain single item.
+	//   - []string - an array of items.
+	//   - []fmt.Stringer - an array of objects convertible to a string.
+	//   - []Color - An array of color values which will be converted to a string array.
+	//   - []any - this array must contain only types which were listed in Types section.
+	//
+	// # Usage in DatePicker
+	//
+	// List of predefined dates. If we set this property, date picker may have a drop-down menu with a list of these values.
+	// Some browsers may ignore this property, such as Safari for macOS. The value of this property must be an array of
+	// strings in the format "YYYY-MM-DD".
+	//
+	// Supported types: []string, string, []fmt.Stringer, []time.Time, []any containing elements of string, fmt.Stringer, time.Time.
+	//
+	// Internal type is []string, other types converted to it during assignment.
+	//
+	// Conversion rules:
+	//   - string - contain single item.
+	//   - []string - an array of items.
+	//   - []fmt.Stringer - an array of objects convertible to a string.
+	//   - []time.Time - an array of Time values which will be converted to a string array.
+	//   - []any - this array must contain only types which were listed in Types section.
+	//
+	// # Usage in EditView
+	//
+	// Array of recommended values.
+	//
+	// Supported types: []string, string, []fmt.Stringer, and []any containing
+	// elements of string, fmt.Stringer, bool, rune, float32, float64, int, int8…int64, uint, uint8…uint64.
+	//
+	// Internal type is []string, other types converted to it during assignment.
+	//
+	// Conversion rules:
+	//   - string - contain single item.
+	//   - []string - an array of items.
+	//   - []fmt.Stringer - an array of objects convertible to a string.
+	//   - []any - this array must contain only types which were listed in Types section.
+	//
+	// # Usage in NumberPicker
+	//
+	// Specify an array of recommended values.
+	//
+	// Supported types: []string, string, []fmt.Stringer, []float, []int, []bool, []any containing elements
+	// of string, fmt.Stringer, rune, float32, float64, int, int8…int64, uint, uint8…uint64.
+	//
+	// Internal type is []string, other types converted to it during assignment.
+	//
+	// Conversion rules:
+	//   - string - must contain integer or floating point number, converted to []string.
+	//   - []string - an array of strings which must contain integer or floating point numbers, stored as is.
+	//   - []fmt.Stringer - object which implement this interface must contain integer or floating point numbers, converted to a []string.
+	//   - []float - converted to []string.
+	//   - []int - converted to []string.
+	//   - []any - an array which may contain types listed in Types section above, each value will be converted to a string and wrapped to array.
+	//
+	// # Usage in TimePicker
+	//
+	// An array of recommended values. The value of this property must be an array of strings in the format "HH:MM:SS" or
+	// "HH:MM".
+	//
+	// Supported types: []string, string, []fmt.Stringer, []time.Time, []any containing elements of string, fmt.Stringer, time.Time.
+	//
+	// Internal type is []string, other types converted to it during assignment.
+	//
+	// Conversion rules:
+	//   - string - contain single item.
+	//   - []string - an array of items.
+	//   - []fmt.Stringer - an array of objects convertible to a string.
+	//   - []time.Time - An array of Time values which will be converted to a string array.
+	//   - []any - this array must contain only types which were listed in Types section.
+	DataList PropertyName = "data-list"
+)
 
-func (list *dataList) dataListInit() {
-	list.dataList = []string{}
-}
-
-func (list *dataList) dataListID(view View) string {
+func dataListID(view View) string {
 	return view.htmlID() + "-datalist"
 }
 
-func (list *dataList) normalizeDataListTag(tag string) string {
+func normalizeDataListTag(tag PropertyName) PropertyName {
 	switch tag {
 	case "datalist":
 		return DataList
@@ -29,69 +108,205 @@ func (list *dataList) normalizeDataListTag(tag string) string {
 	return tag
 }
 
-func (list *dataList) setDataList(view View, value any, created bool) bool {
-	items, ok := anyToStringArray(value)
-	if !ok {
-		notCompatibleType(DataList, value)
-		return false
+func setDataList(properties Properties, value any, dateTimeFormat string) []PropertyName {
+	if items, ok := anyToStringArray(value, dateTimeFormat); ok {
+		properties.setRaw(DataList, items)
+		return []PropertyName{DataList}
 	}
 
-	list.dataList = items
-	if created {
+	notCompatibleType(DataList, value)
+	return nil
+}
+
+func anyToStringArray(value any, dateTimeFormat string) ([]string, bool) {
+
+	switch value := value.(type) {
+	case string:
+		return []string{value}, true
+
+	case []string:
+		return value, true
+
+	case []DataValue:
+		items := make([]string, 0, len(value))
+		for _, val := range value {
+			if !val.IsObject() {
+				items = append(items, val.Value())
+			}
+		}
+		return items, true
+
+	case []fmt.Stringer:
+		items := make([]string, len(value))
+		for i, str := range value {
+			items[i] = str.String()
+		}
+		return items, true
+
+	case []Color:
+		items := make([]string, len(value))
+		for i, str := range value {
+			items[i] = str.String()
+		}
+		return items, true
+
+	case []SizeUnit:
+		items := make([]string, len(value))
+		for i, str := range value {
+			items[i] = str.String()
+		}
+		return items, true
+
+	case []AngleUnit:
+		items := make([]string, len(value))
+		for i, str := range value {
+			items[i] = str.String()
+		}
+		return items, true
+
+	case []float32:
+		items := make([]string, len(value))
+		for i, val := range value {
+			items[i] = fmt.Sprintf("%g", float64(val))
+		}
+		return items, true
+
+	case []float64:
+		items := make([]string, len(value))
+		for i, val := range value {
+			items[i] = fmt.Sprintf("%g", val)
+		}
+		return items, true
+
+	case []int:
+		return intArrayToStringArray(value), true
+
+	case []uint:
+		return intArrayToStringArray(value), true
+
+	case []int8:
+		return intArrayToStringArray(value), true
+
+	case []uint8:
+		return intArrayToStringArray(value), true
+
+	case []int16:
+		return intArrayToStringArray(value), true
+
+	case []uint16:
+		return intArrayToStringArray(value), true
+
+	case []int32:
+		return intArrayToStringArray(value), true
+
+	case []uint32:
+		return intArrayToStringArray(value), true
+
+	case []int64:
+		return intArrayToStringArray(value), true
+
+	case []uint64:
+		return intArrayToStringArray(value), true
+
+	case []bool:
+		items := make([]string, len(value))
+		for i, val := range value {
+			if val {
+				items[i] = "true"
+			} else {
+				items[i] = "false"
+			}
+		}
+		return items, true
+
+	case []time.Time:
+		if dateTimeFormat == "" {
+			dateTimeFormat = dateFormat + " " + timeFormat
+		}
+
+		items := make([]string, len(value))
+		for i, val := range value {
+			items[i] = val.Format(dateTimeFormat)
+		}
+		return items, true
+
+	case []any:
+		items := make([]string, 0, len(value))
+		for _, v := range value {
+			switch val := v.(type) {
+			case string:
+				items = append(items, val)
+
+			case fmt.Stringer:
+				items = append(items, val.String())
+
+			case bool:
+				if val {
+					items = append(items, "true")
+				} else {
+					items = append(items, "false")
+				}
+
+			case float32:
+				items = append(items, fmt.Sprintf("%g", float64(val)))
+
+			case float64:
+				items = append(items, fmt.Sprintf("%g", val))
+
+			case rune:
+				items = append(items, string(val))
+
+			default:
+				if n, ok := isInt(v); ok {
+					items = append(items, strconv.Itoa(n))
+				} else {
+					return []string{}, false
+				}
+			}
+		}
+
+		return items, true
+	}
+
+	return []string{}, false
+}
+
+func getDataListProperty(properties Properties) []string {
+	if value := properties.getRaw(DataList); value != nil {
+		if items, ok := value.([]string); ok {
+			return items
+		}
+	}
+	return nil
+}
+
+func dataListHtmlSubviews(view View, buffer *strings.Builder, normalizeItem func(text string, session Session) string) {
+	if items := getDataListProperty(view); len(items) > 0 {
 		session := view.Session()
-		dataListID := list.dataListID(view)
-		buffer := allocStringBuilder()
-		defer freeStringBuilder(buffer)
+		buffer.WriteString(`<datalist id="`)
+		buffer.WriteString(dataListID(view))
+		buffer.WriteString(`">`)
+		for _, text := range items {
+			text = normalizeItem(text, session)
 
-		if list.dataListHtml {
-			list.dataListItemsHtml(buffer)
-			session.updateInnerHTML(dataListID, buffer.String())
-		} else {
-			list.dataListHtmlCode(view, buffer)
-			session.appendToInnerHTML(view.parentHTMLID(), buffer.String())
-			list.dataListHtml = true
-			session.updateProperty(view.htmlID(), "list", dataListID)
+			if strings.ContainsRune(text, '"') {
+				text = strings.ReplaceAll(text, `"`, `&#34;`)
+			}
+			if strings.ContainsRune(text, '\n') {
+				text = strings.ReplaceAll(text, "\n", `\n`)
+			}
+			buffer.WriteString(`<option value="`)
+			buffer.WriteString(text)
+			buffer.WriteString(`"></option>`)
 		}
-	}
-
-	return true
-}
-
-func (list *dataList) dataListHtmlSubviews(view View, buffer *strings.Builder) {
-	if len(list.dataList) > 0 {
-		list.dataListHtmlCode(view, buffer)
-		list.dataListHtml = true
-	} else {
-		list.dataListHtml = false
+		buffer.WriteString(`</datalist>`)
 	}
 }
 
-func (list *dataList) dataListHtmlCode(view View, buffer *strings.Builder) {
-	buffer.WriteString(`<datalist id="`)
-	buffer.WriteString(list.dataListID(view))
-	buffer.WriteString(`">`)
-	list.dataListItemsHtml(buffer)
-	buffer.WriteString(`</datalist>`)
-}
-
-func (list *dataList) dataListItemsHtml(buffer *strings.Builder) {
-	for _, text := range list.dataList {
-		if strings.ContainsRune(text, '"') {
-			text = strings.ReplaceAll(text, `"`, `&#34;`)
-		}
-		if strings.ContainsRune(text, '\n') {
-			text = strings.ReplaceAll(text, "\n", `\n`)
-		}
-		buffer.WriteString(`<option value="`)
-		buffer.WriteString(text)
-		buffer.WriteString(`"></option>`)
-	}
-}
-
-func (list *dataList) dataListHtmlProperties(view View, buffer *strings.Builder) {
-	if len(list.dataList) > 0 {
+func dataListHtmlProperties(view View, buffer *strings.Builder) {
+	if len(getDataListProperty(view)) > 0 {
 		buffer.WriteString(` list="`)
-		buffer.WriteString(list.dataListID(view))
+		buffer.WriteString(dataListID(view))
 		buffer.WriteString(`"`)
 	}
 }
@@ -99,16 +314,8 @@ func (list *dataList) dataListHtmlProperties(view View, buffer *strings.Builder)
 // GetDataList returns the data list of an editor.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetDataList(view View, subviewID ...string) []string {
-	if len(subviewID) > 0 && subviewID[0] != "" {
-		view = ViewByID(view, subviewID[0])
-	}
-
-	if view != nil {
-		if value := view.Get(DataList); value != nil {
-			if list, ok := value.([]string); ok {
-				return list
-			}
-		}
+	if view = getSubview(view, subviewID); view != nil {
+		return getDataListProperty(view)
 	}
 
 	return []string{}

datePicker.go

@@ -6,24 +6,119 @@ import (
 	"time"
 )
 
+// Constants for [DatePicker] specific properties and events.
 const (
-	DateChangedEvent = "date-changed"
-	DatePickerMin    = "date-picker-min"
-	DatePickerMax    = "date-picker-max"
-	DatePickerStep   = "date-picker-step"
-	DatePickerValue  = "date-picker-value"
-	dateFormat       = "2006-01-02"
+	// DateChangedEvent is the constant for "date-changed" property tag.
+	//
+	// Used by DatePicker.
+	// Occur when date picker value has been changed.
+	//
+	// General listener format:
+	//  func(picker rui.DatePicker, newDate time.Time, oldDate time.Time)
+	//
+	// where:
+	//   - picker - Interface of a date picker which generated this event,
+	//   - newDate - New date value,
+	//   - oldDate - Old date value.
+	//
+	// Allowed listener formats:
+	//  func(picker rui.DatePicker, newDate time.Time)
+	//  func(newDate time.Time, oldDate time.Time)
+	//  func(newDate time.Time)
+	//  func(picker rui.DatePicker)
+	//  func()
+	DateChangedEvent PropertyName = "date-changed"
+
+	// DatePickerMin is the constant for "date-picker-min" property tag.
+	//
+	// Used by DatePicker.
+	// Minimum date value.
+	//
+	// Supported types: time.Time, string.
+	//
+	// Internal type is time.Time, other types converted to it during assignment.
+	//
+	// Conversion rules:
+	// string - values of this type parsed and converted to time.Time. The following formats are supported:
+	//   - "YYYYMMDD" - "20240102".
+	//   - "Mon-DD-YYYY" - "Jan-02-24".
+	//   - "Mon-DD-YY" - "Jan-02-2024".
+	//   - "DD-Mon-YYYY" - "02-Jan-2024".
+	//   - "YYYY-MM-DD" - "2024-01-02".
+	//   - "Month DD, YYYY" - "January 02, 2024".
+	//   - "DD Month YYYY" - "02 January 2024".
+	//   - "MM/DD/YYYY" - "01/02/2024".
+	//   - "MM/DD/YY" - "01/02/24".
+	//   - "MMDDYY" - "010224".
+	DatePickerMin PropertyName = "date-picker-min"
+
+	// DatePickerMax is the constant for "date-picker-max" property tag.
+	//
+	// Used by DatePicker.
+	// Maximum date value.
+	//
+	// Supported types: time.Time, string.
+	//
+	// Internal type is time.Time, other types converted to it during assignment.
+	//
+	// Conversion rules:
+	// string - values of this type parsed and converted to time.Time. The following formats are supported:
+	//   - "YYYYMMDD" - "20240102".
+	//   - "Mon-DD-YYYY" - "Jan-02-24".
+	//   - "Mon-DD-YY" - "Jan-02-2024".
+	//   - "DD-Mon-YYYY" - "02-Jan-2024".
+	//   - "YYYY-MM-DD" - "2024-01-02".
+	//   - "Month DD, YYYY" - "January 02, 2024".
+	//   - "DD Month YYYY" - "02 January 2024".
+	//   - "MM/DD/YYYY" - "01/02/2024".
+	//   - "MM/DD/YY" - "01/02/24".
+	//   - "MMDDYY" - "010224".
+	DatePickerMax PropertyName = "date-picker-max"
+
+	// DatePickerStep is the constant for "date-picker-step" property tag.
+	//
+	// Used by DatePicker.
+	// Date change step in days.
+	//
+	// Supported types: int, string.
+	//
+	// Values:
+	// positive value - Step value in days used to increment or decrement date.
+	DatePickerStep PropertyName = "date-picker-step"
+
+	// DatePickerValue is the constant for "date-picker-value" property tag.
+	//
+	// Used by DatePicker.
+	// Current value.
+	//
+	// Supported types: time.Time, string.
+	//
+	// Internal type is time.Time, other types converted to it during assignment.
+	//
+	// Conversion rules:
+	// string - values of this type parsed and converted to time.Time. The following formats are supported:
+	//   - "YYYYMMDD" - "20240102".
+	//   - "Mon-DD-YYYY" - "Jan-02-24".
+	//   - "Mon-DD-YY" - "Jan-02-2024".
+	//   - "DD-Mon-YYYY" - "02-Jan-2024".
+	//   - "YYYY-MM-DD" - "2024-01-02".
+	//   - "Month DD, YYYY" - "January 02, 2024".
+	//   - "DD Month YYYY" - "02 January 2024".
+	//   - "MM/DD/YYYY" - "01/02/2024".
+	//   - "MM/DD/YY" - "01/02/24".
+	//   - "MMDDYY" - "010224".
+	DatePickerValue PropertyName = "date-picker-value"
+
+	dateFormat = "2006-01-02"
 )
 
-// DatePicker - DatePicker view
+// DatePicker represent a DatePicker view
 type DatePicker interface {
 	View
 }
 
 type datePickerData struct {
 	viewData
-	dataList
-	dateChangedListeners []func(DatePicker, time.Time, time.Time)
 }
 
 // NewDatePicker create new DatePicker object and return it
@@ -35,248 +130,164 @@ func NewDatePicker(session Session, params Params) DatePicker {
 }
 
 func newDatePicker(session Session) View {
-	return NewDatePicker(session, nil)
+	return new(datePickerData) // NewDatePicker(session, nil)
 }
 
 func (picker *datePickerData) init(session Session) {
 	picker.viewData.init(session)
 	picker.tag = "DatePicker"
 	picker.hasHtmlDisabled = true
-	picker.dateChangedListeners = []func(DatePicker, time.Time, time.Time){}
-	picker.dataListInit()
-}
-
-func (picker *datePickerData) String() string {
-	return getViewString(picker, nil)
+	picker.normalize = normalizeDatePickerTag
+	picker.set = picker.setFunc
+	picker.changed = picker.propertyChanged
 }
 
 func (picker *datePickerData) Focusable() bool {
 	return true
 }
 
-func (picker *datePickerData) normalizeTag(tag string) string {
-	tag = strings.ToLower(tag)
+func normalizeDatePickerTag(tag PropertyName) PropertyName {
+	tag = defaultNormalize(tag)
 	switch tag {
 	case Type, Min, Max, Step, Value:
 		return "date-picker-" + tag
 	}
 
-	return tag
+	return normalizeDataListTag(tag)
 }
 
-func (picker *datePickerData) Remove(tag string) {
-	picker.remove(picker.normalizeTag(tag))
-}
-
-func (picker *datePickerData) remove(tag string) {
-	switch tag {
-	case DateChangedEvent:
-		if len(picker.dateChangedListeners) > 0 {
-			picker.dateChangedListeners = []func(DatePicker, time.Time, time.Time){}
-			picker.propertyChangedEvent(tag)
-		}
-		return
-
-	case DatePickerMin:
-		delete(picker.properties, DatePickerMin)
-		if picker.created {
-			picker.session.removeProperty(picker.htmlID(), Min)
-		}
-
-	case DatePickerMax:
-		delete(picker.properties, DatePickerMax)
-		if picker.created {
-			picker.session.removeProperty(picker.htmlID(), Max)
-		}
-
-	case DatePickerStep:
-		delete(picker.properties, DatePickerStep)
-		if picker.created {
-			picker.session.removeProperty(picker.htmlID(), Step)
-		}
-
-	case DatePickerValue:
-		if _, ok := picker.properties[DatePickerValue]; ok {
-			oldDate := GetDatePickerValue(picker)
-			delete(picker.properties, DatePickerValue)
-			date := GetDatePickerValue(picker)
-			if picker.created {
-				picker.session.callFunc("setInputValue", picker.htmlID(), date.Format(dateFormat))
+func stringToDate(value string) (time.Time, bool) {
+	format := "20060102"
+	if strings.ContainsRune(value, '-') {
+		if part := strings.Split(value, "-"); len(part) == 3 {
+			if part[0] != "" && part[0][0] > '9' {
+				if len(part[2]) == 2 {
+					format = "Jan-02-06"
+				} else {
+					format = "Jan-02-2006"
+				}
+			} else if part[1] != "" && part[1][0] > '9' {
+				format = "02-Jan-2006"
+			} else {
+				format = "2006-01-02"
 			}
-			for _, listener := range picker.dateChangedListeners {
-				listener(picker, date, oldDate)
+		}
+	} else if strings.ContainsRune(value, ' ') {
+		if part := strings.Split(value, " "); len(part) == 3 {
+			if part[0] != "" && part[0][0] > '9' {
+				format = "January 02, 2006"
+			} else {
+				format = "02 January 2006"
 			}
-		} else {
-			return
 		}
-
-	case DataList:
-		if len(picker.dataList.dataList) > 0 {
-			picker.setDataList(picker, []string{}, true)
+	} else if strings.ContainsRune(value, '/') {
+		if part := strings.Split(value, "/"); len(part) == 3 {
+			if len(part[2]) == 2 {
+				format = "01/02/06"
+			} else {
+				format = "01/02/2006"
+			}
 		}
-
-	default:
-		picker.viewData.remove(tag)
-		return
-	}
-	picker.propertyChangedEvent(tag)
-}
-
-func (picker *datePickerData) Set(tag string, value any) bool {
-	return picker.set(picker.normalizeTag(tag), value)
-}
-
-func (picker *datePickerData) set(tag string, value any) bool {
-	if value == nil {
-		picker.remove(tag)
-		return true
+	} else if len(value) == 6 {
+		format = "010206"
 	}
 
-	setTimeValue := func(tag string) (time.Time, bool) {
+	if date, err := time.Parse(format, value); err == nil {
+		return date, true
+	}
+	return time.Now(), false
+}
+
+func (picker *datePickerData) setFunc(tag PropertyName, value any) []PropertyName {
+
+	setDateValue := func(tag PropertyName) []PropertyName {
 		switch value := value.(type) {
 		case time.Time:
-			picker.properties[tag] = value
-			return value, true
+			picker.setRaw(tag, value)
+			return []PropertyName{tag}
 
 		case string:
-			if text, ok := picker.Session().resolveConstants(value); ok {
-				format := "20060102"
-				if strings.ContainsRune(text, '-') {
-					if part := strings.Split(text, "-"); len(part) == 3 {
-						if part[0] != "" && part[0][0] > '9' {
-							if len(part[2]) == 2 {
-								format = "Jan-02-06"
-							} else {
-								format = "Jan-02-2006"
-							}
-						} else if part[1] != "" && part[1][0] > '9' {
-							format = "02-Jan-2006"
-						} else {
-							format = "2006-01-02"
-						}
-					}
-				} else if strings.ContainsRune(text, ' ') {
-					if part := strings.Split(text, " "); len(part) == 3 {
-						if part[0] != "" && part[0][0] > '9' {
-							format = "January 02, 2006"
-						} else {
-							format = "02 January 2006"
-						}
-					}
-				} else if strings.ContainsRune(text, '/') {
-					if part := strings.Split(text, "/"); len(part) == 3 {
-						if len(part[2]) == 2 {
-							format = "01/02/06"
-						} else {
-							format = "01/02/2006"
-						}
-					}
-				} else if len(text) == 6 {
-					format = "010206"
-				}
+			if isConstantName(value) {
+				picker.setRaw(tag, value)
+				return []PropertyName{tag}
+			}
 
-				if date, err := time.Parse(format, text); err == nil {
-					picker.properties[tag] = value
-					return date, true
-				}
+			if date, ok := stringToDate(value); ok {
+				picker.setRaw(tag, date)
+				return []PropertyName{tag}
 			}
 		}
 
 		notCompatibleType(tag, value)
-		return time.Now(), false
+		return nil
 	}
 
 	switch tag {
+	case DatePickerMin, DatePickerMax:
+		return setDateValue(tag)
+
+	case DatePickerStep:
+		return setIntProperty(picker, DatePickerStep, value)
+
+	case DatePickerValue:
+		picker.setRaw("old-date", GetDatePickerValue(picker))
+		return setDateValue(tag)
+
+	case DateChangedEvent:
+		return setTwoArgEventListener[DatePicker, time.Time](picker, tag, value)
+
+	case DataList:
+		return setDataList(picker, value, dateFormat)
+	}
+
+	return picker.viewData.setFunc(tag, value)
+}
+
+func (picker *datePickerData) propertyChanged(tag PropertyName) {
+
+	session := picker.Session()
+
+	switch tag {
+
 	case DatePickerMin:
-		old, oldOK := getDateProperty(picker, DatePickerMin, Min)
-		if date, ok := setTimeValue(DatePickerMin); ok {
-			if !oldOK || date != old {
-				if picker.created {
-					picker.session.updateProperty(picker.htmlID(), Min, date.Format(dateFormat))
-				}
-				picker.propertyChangedEvent(tag)
-			}
-			return true
+		if date, ok := GetDatePickerMin(picker); ok {
+			session.updateProperty(picker.htmlID(), "min", date.Format(dateFormat))
+		} else {
+			session.removeProperty(picker.htmlID(), "min")
 		}
 
 	case DatePickerMax:
-		old, oldOK := getDateProperty(picker, DatePickerMax, Max)
-		if date, ok := setTimeValue(DatePickerMax); ok {
-			if !oldOK || date != old {
-				if picker.created {
-					picker.session.updateProperty(picker.htmlID(), Max, date.Format(dateFormat))
-				}
-				picker.propertyChangedEvent(tag)
-			}
-			return true
+		if date, ok := GetDatePickerMax(picker); ok {
+			session.updateProperty(picker.htmlID(), "max", date.Format(dateFormat))
+		} else {
+			session.removeProperty(picker.htmlID(), "max")
 		}
 
 	case DatePickerStep:
-		oldStep := GetDatePickerStep(picker)
-		if picker.setIntProperty(DatePickerStep, value) {
-			if step := GetDatePickerStep(picker); oldStep != step {
-				if picker.created {
-					if step > 0 {
-						picker.session.updateProperty(picker.htmlID(), Step, strconv.Itoa(step))
-					} else {
-						picker.session.removeProperty(picker.htmlID(), Step)
-					}
-				}
-				picker.propertyChangedEvent(tag)
-			}
-			return true
+		if step := GetDatePickerStep(picker); step > 0 {
+			session.updateProperty(picker.htmlID(), "step", strconv.Itoa(step))
+		} else {
+			session.removeProperty(picker.htmlID(), "step")
 		}
 
 	case DatePickerValue:
-		oldDate := GetDatePickerValue(picker)
-		if date, ok := setTimeValue(DatePickerValue); ok {
-			if date != oldDate {
-				if picker.created {
-					picker.session.callFunc("setInputValue", picker.htmlID(), date.Format(dateFormat))
+		date := GetDatePickerValue(picker)
+		session.callFunc("setInputValue", picker.htmlID(), date.Format(dateFormat))
+
+		if listeners := GetDateChangedListeners(picker); len(listeners) > 0 {
+			oldDate := time.Now()
+			if value := picker.getRaw("old-date"); value != nil {
+				if date, ok := value.(time.Time); ok {
+					oldDate = date
 				}
-				for _, listener := range picker.dateChangedListeners {
-					listener(picker, date, oldDate)
-				}
-				picker.propertyChangedEvent(tag)
 			}
-			return true
+			for _, listener := range listeners {
+				listener(picker, date, oldDate)
+			}
 		}
 
-	case DateChangedEvent:
-		listeners, ok := valueToEventWithOldListeners[DatePicker, time.Time](value)
-		if !ok {
-			notCompatibleType(tag, value)
-			return false
-		} else if listeners == nil {
-			listeners = []func(DatePicker, time.Time, time.Time){}
-		}
-		picker.dateChangedListeners = listeners
-		picker.propertyChangedEvent(tag)
-		return true
-
-	case DataList:
-		return picker.setDataList(picker, value, picker.created)
-
 	default:
-		return picker.viewData.set(tag, value)
-	}
-	return false
-}
-
-func (picker *datePickerData) Get(tag string) any {
-	return picker.get(picker.normalizeTag(tag))
-}
-
-func (picker *datePickerData) get(tag string) any {
-	switch tag {
-	case DateChangedEvent:
-		return picker.dateChangedListeners
-
-	case DataList:
-		return picker.dataList.dataList
-
-	default:
-		return picker.viewData.get(tag)
+		picker.viewData.propertyChanged(tag)
 	}
 }
 
@@ -285,7 +296,13 @@ func (picker *datePickerData) htmlTag() string {
 }
 
 func (picker *datePickerData) htmlSubviews(self View, buffer *strings.Builder) {
-	picker.dataListHtmlSubviews(self, buffer)
+	dataListHtmlSubviews(self, buffer, func(text string, session Session) string {
+		text, _ = session.resolveConstants(text)
+		if date, ok := stringToDate(text); ok {
+			return date.Format(dateFormat)
+		}
+		return text
+	})
 }
 
 func (picker *datePickerData) htmlProperties(self View, buffer *strings.Builder) {
@@ -320,10 +337,10 @@ func (picker *datePickerData) htmlProperties(self View, buffer *strings.Builder)
 		buffer.WriteString(` onclick="stopEventPropagation(this, event)"`)
 	}
 
-	picker.dataListHtmlProperties(picker, buffer)
+	dataListHtmlProperties(picker, buffer)
 }
 
-func (picker *datePickerData) handleCommand(self View, command string, data DataObject) bool {
+func (picker *datePickerData) handleCommand(self View, command PropertyName, data DataObject) bool {
 	switch command {
 	case "textChanged":
 		if text, ok := data.PropertyValue("text"); ok {
@@ -331,9 +348,12 @@ func (picker *datePickerData) handleCommand(self View, command string, data Data
 				oldValue := GetDatePickerValue(picker)
 				picker.properties[DatePickerValue] = value
 				if value != oldValue {
-					for _, listener := range picker.dateChangedListeners {
+					for _, listener := range GetDateChangedListeners(picker) {
 						listener(picker, value, oldValue)
 					}
+					if listener, ok := picker.changeListener[DatePickerValue]; ok {
+						listener(picker, DatePickerValue)
+					}
 				}
 			}
 		}
@@ -343,7 +363,7 @@ func (picker *datePickerData) handleCommand(self View, command string, data Data
 	return picker.viewData.handleCommand(self, command, data)
 }
 
-func getDateProperty(view View, mainTag, shortTag string) (time.Time, bool) {
+func getDateProperty(view View, mainTag, shortTag PropertyName) (time.Time, bool) {
 	valueToTime := func(value any) (time.Time, bool) {
 		if value != nil {
 			switch value := value.(type) {
@@ -352,7 +372,7 @@ func getDateProperty(view View, mainTag, shortTag string) (time.Time, bool) {
 
 			case string:
 				if text, ok := view.Session().resolveConstants(value); ok {
-					if result, err := time.Parse(dateFormat, text); err == nil {
+					if result, ok := stringToDate(text); ok {
 						return result, true
 					}
 				}
@@ -366,9 +386,11 @@ func getDateProperty(view View, mainTag, shortTag string) (time.Time, bool) {
 			return result, true
 		}
 
-		if value := valueFromStyle(view, shortTag); value != nil {
-			if result, ok := valueToTime(value); ok {
-				return result, true
+		for _, tag := range []PropertyName{mainTag, shortTag} {
+			if value := valueFromStyle(view, tag); value != nil {
+				if result, ok := valueToTime(value); ok {
+					return result, true
+				}
 			}
 		}
 	}
@@ -380,10 +402,7 @@ func getDateProperty(view View, mainTag, shortTag string) (time.Time, bool) {
 // "false" as the second value otherwise.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetDatePickerMin(view View, subviewID ...string) (time.Time, bool) {
-	if len(subviewID) > 0 && subviewID[0] != "" {
-		view = ViewByID(view, subviewID[0])
-	}
-	if view != nil {
+	if view = getSubview(view, subviewID); view != nil {
 		return getDateProperty(view, DatePickerMin, Min)
 	}
 	return time.Now(), false
@@ -393,10 +412,7 @@ func GetDatePickerMin(view View, subviewID ...string) (time.Time, bool) {
 // "false" as the second value otherwise.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetDatePickerMax(view View, subviewID ...string) (time.Time, bool) {
-	if len(subviewID) > 0 && subviewID[0] != "" {
-		view = ViewByID(view, subviewID[0])
-	}
-	if view != nil {
+	if view = getSubview(view, subviewID); view != nil {
 		return getDateProperty(view, DatePickerMax, Max)
 	}
 	return time.Now(), false
@@ -411,10 +427,7 @@ func GetDatePickerStep(view View, subviewID ...string) int {
 // GetDatePickerValue returns the date of DatePicker subview.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetDatePickerValue(view View, subviewID ...string) time.Time {
-	if len(subviewID) > 0 && subviewID[0] != "" {
-		view = ViewByID(view, subviewID[0])
-	}
-	if view == nil {
+	if view = getSubview(view, subviewID); view == nil {
 		return time.Now()
 	}
 	date, _ := getDateProperty(view, DatePickerValue, Value)
@@ -425,5 +438,5 @@ func GetDatePickerValue(view View, subviewID ...string) time.Time {
 // If there are no listeners then the empty list is returned
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetDateChangedListeners(view View, subviewID ...string) []func(DatePicker, time.Time, time.Time) {
-	return getEventWithOldListeners[DatePicker, time.Time](view, subviewID, DateChangedEvent)
+	return getTwoArgEventListeners[DatePicker, time.Time](view, subviewID, DateChangedEvent)
 }

defaultTheme.rui

@@ -136,8 +136,8 @@ theme {
 			margin = 2px,
 		},
 		ruiCheckbox:focus {
-			margin = 0,
-			border = _{style = solid, color = @ruiHighlightColor, width = 2px },
+			outline = _{style = solid, color = @ruiHighlightColor, width = 2px },
+			outline-offset = -1px,
 		},
 		ruiListItem {
 			radius = 4px,

detailsView.go

@@ -2,17 +2,44 @@ package rui
 
 import "strings"
 
+// Constants for [DetailsView] specific properties and events
 const (
-	// Summary is the constant for the "summary" property tag.
-	// The contents of the "summary" property are used as the label for the disclosure widget.
-	Summary = "summary"
-	// Expanded is the constant for the "expanded" property tag.
-	// If the "expanded" boolean property is "true", then the content of view is visible.
-	// If the value is "false" then the content is collapsed.
-	Expanded = "expanded"
+	// Summary is the constant for "summary" property tag.
+	//
+	// Used by DetailsView.
+	// The content of this property is used as the label for the disclosure widget.
+	//
+	// Supported types:
+	//   - string - Summary as a text.
+	//   - View - Summary as a view, in this case it can be quite complex if needed.
+	Summary PropertyName = "summary"
+
+	// Expanded is the constant for "expanded" property tag.
+	//
+	// Used by DetailsView.
+	// Controls the content expanded state of the details view. Default value is false.
+	//
+	// Supported types: bool, int, string.
+	//
+	// Values:
+	//   - true, 1, "true", "yes", "on", or "1" - Content is visible.
+	//   - false, 0, "false", "no", "off", or "0" - Content is collapsed (hidden).
+	Expanded PropertyName = "expanded"
+
+	// HideSummaryMarker is the constant for "hide-summary-marker" property tag.
+	//
+	// Used by DetailsView.
+	// Allows you to hide the summary marker (▶︎). Default value is false.
+	//
+	// Supported types: bool, int, string.
+	//
+	// Values:
+	//   - true, 1, "true", "yes", "on", or "1" - The summary marker is hidden.
+	//   - false, 0, "false", "no", "off", or "0" - The summary marker is displayed (default value).
+	HideSummaryMarker PropertyName = "hide-summary-marker"
 )
 
-// DetailsView - collapsible container of View
+// DetailsView represent a DetailsView view, which is a collapsible container of views
 type DetailsView interface {
 	ViewsContainer
 }
@@ -30,19 +57,21 @@ func NewDetailsView(session Session, params Params) DetailsView {
 }
 
 func newDetailsView(session Session) View {
-	return NewDetailsView(session, nil)
+	return new(detailsViewData)
 }
 
 // Init initialize fields of DetailsView by default values
 func (detailsView *detailsViewData) init(session Session) {
 	detailsView.viewsContainerData.init(session)
 	detailsView.tag = "DetailsView"
+	detailsView.set = detailsView.setFunc
+	detailsView.changed = detailsView.propertyChanged
 	//detailsView.systemClass = "ruiDetailsView"
 }
 
 func (detailsView *detailsViewData) Views() []View {
 	views := detailsView.viewsContainerData.Views()
-	if summary := detailsView.get(Summary); summary != nil {
+	if summary := detailsView.Get(Summary); summary != nil {
 		switch summary := summary.(type) {
 		case View:
 			return append([]View{summary}, views...)
@@ -51,94 +80,53 @@ func (detailsView *detailsViewData) Views() []View {
 	return views
 }
 
-func (detailsView *detailsViewData) Remove(tag string) {
-	detailsView.remove(strings.ToLower(tag))
-}
-
-func (detailsView *detailsViewData) remove(tag string) {
-	detailsView.viewsContainerData.remove(tag)
-	if detailsView.created {
-		switch tag {
-		case Summary:
-			updateInnerHTML(detailsView.htmlID(), detailsView.Session())
-
-		case Expanded:
-			detailsView.session.removeProperty(detailsView.htmlID(), "open")
-		}
-	}
-}
-
-func (detailsView *detailsViewData) Set(tag string, value any) bool {
-	return detailsView.set(strings.ToLower(tag), value)
-}
-
-func (detailsView *detailsViewData) set(tag string, value any) bool {
-	if value == nil {
-		detailsView.remove(tag)
-		return true
-	}
-
+func (detailsView *detailsViewData) setFunc(tag PropertyName, value any) []PropertyName {
 	switch tag {
 	case Summary:
 		switch value := value.(type) {
 		case string:
-			detailsView.properties[Summary] = value
+			detailsView.setRaw(Summary, value)
 
 		case View:
-			detailsView.properties[Summary] = value
+			detailsView.setRaw(Summary, value)
 			value.setParentID(detailsView.htmlID())
 
 		case DataObject:
 			if view := CreateViewFromObject(detailsView.Session(), value); view != nil {
-				detailsView.properties[Summary] = view
+				detailsView.setRaw(Summary, view)
 				view.setParentID(detailsView.htmlID())
 			} else {
-				return false
+				return nil
 			}
 
 		default:
 			notCompatibleType(tag, value)
-			return false
-		}
-		if detailsView.created {
-			updateInnerHTML(detailsView.htmlID(), detailsView.Session())
+			return nil
 		}
+		return []PropertyName{tag}
+	}
+
+	return detailsView.viewsContainerData.setFunc(tag, value)
+}
+
+func (detailsView *detailsViewData) propertyChanged(tag PropertyName) {
+	switch tag {
+	case Summary, HideSummaryMarker:
+		updateInnerHTML(detailsView.htmlID(), detailsView.Session())
 
 	case Expanded:
-		if !detailsView.setBoolProperty(tag, value) {
-			notCompatibleType(tag, value)
-			return false
-		}
-		if detailsView.created {
-			if IsDetailsExpanded(detailsView) {
-				detailsView.session.updateProperty(detailsView.htmlID(), "open", "")
-			} else {
-				detailsView.session.removeProperty(detailsView.htmlID(), "open")
-			}
+		if IsDetailsExpanded(detailsView) {
+			detailsView.Session().updateProperty(detailsView.htmlID(), "open", "")
+		} else {
+			detailsView.Session().removeProperty(detailsView.htmlID(), "open")
 		}
 
 	case NotTranslate:
-		if !detailsView.viewData.set(tag, value) {
-			return false
-		}
-		if detailsView.created {
-			updateInnerHTML(detailsView.htmlID(), detailsView.Session())
-		}
+		updateInnerHTML(detailsView.htmlID(), detailsView.Session())
 
 	default:
-		return detailsView.viewsContainerData.Set(tag, value)
+		detailsView.viewsContainerData.propertyChanged(tag)
 	}
-
-	detailsView.propertyChangedEvent(tag)
-	return true
-}
-
-func (detailsView *detailsViewData) Get(tag string) any {
-	return detailsView.get(strings.ToLower(tag))
-}
-
-func (detailsView *detailsViewData) get(tag string) any {
-	return detailsView.viewsContainerData.get(tag)
 }
 
 func (detailsView *detailsViewData) htmlTag() string {
@@ -154,31 +142,59 @@ func (detailsView *detailsViewData) htmlProperties(self View, buffer *strings.Bu
 }
 
 func (detailsView *detailsViewData) htmlSubviews(self View, buffer *strings.Builder) {
+	summary := false
+	hidden := IsSummaryMarkerHidden(detailsView)
+
 	if value, ok := detailsView.properties[Summary]; ok {
+
 		switch value := value.(type) {
 		case string:
 			if !GetNotTranslate(detailsView) {
 				value, _ = detailsView.session.GetString(value)
 			}
-			buffer.WriteString("<summary>")
+			if hidden {
+				buffer.WriteString(`<summary class="hiddenMarker">`)
+			} else {
+				buffer.WriteString("<summary>")
+			}
 			buffer.WriteString(value)
 			buffer.WriteString("</summary>")
+			summary = true
 
 		case View:
-			buffer.WriteString("<summary>")
-			viewHTML(value, buffer)
-			buffer.WriteString("</summary>")
+			if hidden {
+				buffer.WriteString(`<summary class="hiddenMarker">`)
+				viewHTML(value, buffer, "")
+				buffer.WriteString("</summary>")
+			} else if value.htmlTag() == "div" {
+				viewHTML(value, buffer, "summary")
+			} else {
+				buffer.WriteString(`<summary><div style="display: inline-block;">`)
+				viewHTML(value, buffer, "")
+				buffer.WriteString("</div></summary>")
+			}
+			summary = true
+		}
+	}
+
+	if !summary {
+		if hidden {
+			buffer.WriteString(`<summary class="hiddenMarker"></summary>`)
+		} else {
+			buffer.WriteString("<summary></summary>")
 		}
 	}
 
 	detailsView.viewsContainerData.htmlSubviews(self, buffer)
 }
 
-func (detailsView *detailsViewData) handleCommand(self View, command string, data DataObject) bool {
+func (detailsView *detailsViewData) handleCommand(self View, command PropertyName, data DataObject) bool {
 	if command == "details-open" {
 		if n, ok := dataIntProperty(data, "open"); ok {
 			detailsView.properties[Expanded] = (n != 0)
-			detailsView.propertyChangedEvent(Expanded)
+			if listener, ok := detailsView.changeListener[Expanded]; ok {
+				listener(detailsView, Expanded)
+			}
 		}
 		return true
 	}
@@ -188,10 +204,7 @@ func (detailsView *detailsViewData) handleCommand(self View, command string, dat
 // GetDetailsSummary returns a value of the Summary property of DetailsView.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetDetailsSummary(view View, subviewID ...string) View {
-	if len(subviewID) > 0 && subviewID[0] != "" {
-		view = ViewByID(view, subviewID[0])
-	}
-	if view != nil {
+	if view = getSubview(view, subviewID); view != nil {
 		if value := view.Get(Summary); value != nil {
 			switch value := value.(type) {
 			case string:
@@ -210,3 +223,9 @@ func GetDetailsSummary(view View, subviewID ...string) View {
 func IsDetailsExpanded(view View, subviewID ...string) bool {
 	return boolStyledProperty(view, subviewID, Expanded, false)
 }
+
+// IsDetailsExpanded returns a value of the HideSummaryMarker property of DetailsView.
+// If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
+func IsSummaryMarkerHidden(view View, subviewID ...string) bool {
+	return boolStyledProperty(view, subviewID, HideSummaryMarker, false)
+}

dropDownList.go

@@ -1,27 +1,37 @@
 package rui
 
 import (
-	"fmt"
 	"strconv"
 	"strings"
 )
 
 // DropDownEvent is the constant for "drop-down-event" property tag.
-// The "drop-down-event" event occurs when a list item becomes selected.
-// The main listener format: func(DropDownList, int), where the second argument is the item index.
-const DropDownEvent = "drop-down-event"
+//
+// Used by DropDownList.
+// Occur when a list item becomes selected.
+//
+// General listener format:
+//
+//	func(list rui.DropDownList, index int)
+//
+// where:
+//   - list - Interface of a drop down list which generated this event,
+//   - index - Index of a newly selected item.
+//
+// Allowed listener formats:
+//
+//	func(index int)
+//	func(list rui.DropDownList)
+//	func()
+const DropDownEvent PropertyName = "drop-down-event"
 
-// DropDownList - the interface of a drop-down list view
+// DropDownList represent a DropDownList view
 type DropDownList interface {
 	View
-	getItems() []string
 }
 
 type dropDownListData struct {
 	viewData
-	items            []string
-	disabledItems    []any
-	dropDownListener []func(DropDownList, int, int)
 }
 
 // NewDropDownList create new DropDownList object and return it
@@ -33,135 +43,76 @@ func NewDropDownList(session Session, params Params) DropDownList {
 }
 
 func newDropDownList(session Session) View {
-	return NewDropDownList(session, nil)
+	return new(dropDownListData)
 }
 
 func (list *dropDownListData) init(session Session) {
 	list.viewData.init(session)
 	list.tag = "DropDownList"
 	list.hasHtmlDisabled = true
-	list.items = []string{}
-	list.disabledItems = []any{}
-	list.dropDownListener = []func(DropDownList, int, int){}
-}
-
-func (list *dropDownListData) String() string {
-	return getViewString(list, nil)
+	list.normalize = normalizeDropDownListTag
+	list.set = list.setFunc
+	list.changed = list.propertyChanged
 }
 
 func (list *dropDownListData) Focusable() bool {
 	return true
 }
 
-func (list *dropDownListData) Remove(tag string) {
-	list.remove(strings.ToLower(tag))
+func normalizeDropDownListTag(tag PropertyName) PropertyName {
+	tag = defaultNormalize(tag)
+	if tag == "separators" {
+		return ItemSeparators
+	}
+	return tag
 }
 
-func (list *dropDownListData) remove(tag string) {
+func (list *dropDownListData) setFunc(tag PropertyName, value any) []PropertyName {
 	switch tag {
 	case Items:
-		if len(list.items) > 0 {
-			list.items = []string{}
-			if list.created {
-				updateInnerHTML(list.htmlID(), list.session)
-			}
-			list.propertyChangedEvent(tag)
+		if items, ok := anyToStringArray(value, ""); ok {
+			return setArrayPropertyValue(list, tag, items)
 		}
+		notCompatibleType(Items, value)
+		return nil
 
-	case DisabledItems:
-		if len(list.disabledItems) > 0 {
-			list.disabledItems = []any{}
-			if list.created {
-				updateInnerHTML(list.htmlID(), list.session)
-			}
-			list.propertyChangedEvent(tag)
+	case DisabledItems, ItemSeparators:
+		if items, ok := parseIndicesArray(value); ok {
+			return setArrayPropertyValue(list, tag, items)
 		}
+		notCompatibleType(tag, value)
+		return nil
 
 	case DropDownEvent:
-		if len(list.dropDownListener) > 0 {
-			list.dropDownListener = []func(DropDownList, int, int){}
-			list.propertyChangedEvent(tag)
-		}
+		return setTwoArgEventListener[DropDownList, int](list, tag, value)
 
 	case Current:
-		oldCurrent := GetCurrent(list)
-		delete(list.properties, Current)
-		if oldCurrent != 0 {
-			if list.created {
-				list.session.callFunc("selectDropDownListItem", list.htmlID(), 0)
-			}
-			list.onSelectedItemChanged(0, oldCurrent)
+		list.setRaw("old-current", GetCurrent(list))
+		return setIntProperty(list, Current, value)
+	}
+
+	return list.viewData.setFunc(tag, value)
+}
+
+func (list *dropDownListData) propertyChanged(tag PropertyName) {
+	switch tag {
+	case Items, DisabledItems, ItemSeparators:
+		updateInnerHTML(list.htmlID(), list.Session())
+
+	case Current:
+		current := GetCurrent(list)
+		list.Session().callFunc("selectDropDownListItem", list.htmlID(), current)
+
+		oldCurrent, _ := intProperty(list, "old-current", list.Session(), -1)
+		for _, listener := range GetDropDownListeners(list) {
+			listener(list, current, oldCurrent)
 		}
 
 	default:
-		list.viewData.remove(tag)
-		return
+		list.viewData.propertyChanged(tag)
 	}
 }
 
-func (list *dropDownListData) Set(tag string, value any) bool {
-	return list.set(strings.ToLower(tag), value)
-}
-
-func (list *dropDownListData) set(tag string, value any) bool {
-	if value == nil {
-		list.remove(tag)
-		return true
-	}
-
-	switch tag {
-	case Items:
-		return list.setItems(value)
-
-	case DisabledItems:
-		return list.setDisabledItems(value)
-
-	case DropDownEvent:
-		listeners, ok := valueToEventWithOldListeners[DropDownList, int](value)
-		if !ok {
-			notCompatibleType(tag, value)
-			return false
-		} else if listeners == nil {
-			listeners = []func(DropDownList, int, int){}
-		}
-		list.dropDownListener = listeners
-		list.propertyChangedEvent(tag)
-		return true
-
-	case Current:
-		oldCurrent := GetCurrent(list)
-		if !list.setIntProperty(Current, value) {
-			return false
-		}
-
-		if current := GetCurrent(list); oldCurrent != current {
-			if list.created {
-				list.session.callFunc("selectDropDownListItem", list.htmlID(), current)
-			}
-			list.onSelectedItemChanged(current, oldCurrent)
-		}
-		return true
-	}
-
-	return list.viewData.set(tag, value)
-}
-
-func (list *dropDownListData) setItems(value any) bool {
-	items, ok := anyToStringArray(value)
-	if !ok {
-		notCompatibleType(Items, value)
-		return false
-	}
-
-	list.items = items
-	if list.created {
-		updateInnerHTML(list.htmlID(), list.session)
-	}
-
-	list.propertyChangedEvent(Items)
-	return true
-}
-
 func intArrayToStringArray[T int | uint | int8 | uint8 | int16 | uint16 | int32 | uint32 | int64 | uint64](array []T) []string {
 	items := make([]string, len(array))
 	for i, val := range array {
@@ -170,14 +121,60 @@ func intArrayToStringArray[T int | uint | int8 | uint8 | int16 | uint16 | int32
 	return items
 }
 
-func anyToStringArray(value any) ([]string, bool) {
-
+func parseIndicesArray(value any) ([]any, bool) {
 	switch value := value.(type) {
-	case string:
-		return []string{value}, true
+	case int:
+		return []any{value}, true
+
+	case []int:
+		items := make([]any, len(value))
+		for i, n := range value {
+			items[i] = n
+		}
+		return items, true
+
+	case []any:
+		items := make([]any, 0, len(value))
+		for _, val := range value {
+			if val != nil {
+				switch val := val.(type) {
+				case string:
+					if isConstantName(val) {
+						items = append(items, val)
+					} else if n, err := strconv.Atoi(val); err == nil {
+						items = append(items, n)
+					} else {
+						return nil, false
+					}
+
+				default:
+					if n, ok := isInt(val); ok {
+						items = append(items, n)
+					} else {
+						return nil, false
+					}
+				}
+			}
+		}
+		return items, true
 
 	case []string:
-		return value, true
+		items := make([]any, 0, len(value))
+		for _, str := range value {
+			if str = strings.Trim(str, " \t"); str != "" {
+				if isConstantName(str) {
+					items = append(items, str)
+				} else if n, err := strconv.Atoi(str); err == nil {
+					items = append(items, n)
+				} else {
+					return nil, false
+				}
+			}
+		}
+		return items, true
+
+	case string:
+		return parseIndicesArray(strings.Split(value, ","))
 
 	case []DataValue:
 		items := make([]string, 0, len(value))
@@ -186,242 +183,10 @@ func anyToStringArray(value any) ([]string, bool) {
 				items = append(items, val.Value())
 			}
 		}
-		return items, true
-
-	case []fmt.Stringer:
-		items := make([]string, len(value))
-		for i, str := range value {
-			items[i] = str.String()
-		}
-		return items, true
-
-	case []Color:
-		items := make([]string, len(value))
-		for i, str := range value {
-			items[i] = str.String()
-		}
-		return items, true
-
-	case []SizeUnit:
-		items := make([]string, len(value))
-		for i, str := range value {
-			items[i] = str.String()
-		}
-		return items, true
-
-	case []AngleUnit:
-		items := make([]string, len(value))
-		for i, str := range value {
-			items[i] = str.String()
-		}
-		return items, true
-
-	case []float32:
-		items := make([]string, len(value))
-		for i, val := range value {
-			items[i] = fmt.Sprintf("%g", float64(val))
-		}
-		return items, true
-
-	case []float64:
-		items := make([]string, len(value))
-		for i, val := range value {
-			items[i] = fmt.Sprintf("%g", val)
-		}
-		return items, true
-
-	case []int:
-		return intArrayToStringArray(value), true
-
-	case []uint:
-		return intArrayToStringArray(value), true
-
-	case []int8:
-		return intArrayToStringArray(value), true
-
-	case []uint8:
-		return intArrayToStringArray(value), true
-
-	case []int16:
-		return intArrayToStringArray(value), true
-
-	case []uint16:
-		return intArrayToStringArray(value), true
-
-	case []int32:
-		return intArrayToStringArray(value), true
-
-	case []uint32:
-		return intArrayToStringArray(value), true
-
-	case []int64:
-		return intArrayToStringArray(value), true
-
-	case []uint64:
-		return intArrayToStringArray(value), true
-
-	case []bool:
-		items := make([]string, len(value))
-		for i, val := range value {
-			if val {
-				items[i] = "true"
-			} else {
-				items[i] = "false"
-			}
-		}
-		return items, true
-
-	case []any:
-		items := make([]string, 0, len(value))
-		for _, v := range value {
-			switch val := v.(type) {
-			case string:
-				items = append(items, val)
-
-			case fmt.Stringer:
-				items = append(items, val.String())
-
-			case bool:
-				if val {
-					items = append(items, "true")
-				} else {
-					items = append(items, "false")
-				}
-
-			case float32:
-				items = append(items, fmt.Sprintf("%g", float64(val)))
-
-			case float64:
-				items = append(items, fmt.Sprintf("%g", val))
-
-			case rune:
-				items = append(items, string(val))
-
-			default:
-				if n, ok := isInt(v); ok {
-					items = append(items, strconv.Itoa(n))
-				} else {
-					return []string{}, false
-				}
-			}
-		}
-
-		return items, true
+		return parseIndicesArray(items)
 	}
 
-	return []string{}, false
-}
-
-func (list *dropDownListData) setDisabledItems(value any) bool {
-	switch value := value.(type) {
-	case []int:
-		list.disabledItems = make([]any, len(value))
-		for i, n := range value {
-			list.disabledItems[i] = n
-		}
-
-	case []any:
-		disabledItems := make([]any, len(value))
-		for i, val := range value {
-			if val == nil {
-				notCompatibleType(DisabledItems, value)
-				return false
-			}
-
-			switch val := val.(type) {
-			case string:
-				if isConstantName(val) {
-					disabledItems[i] = val
-				} else {
-					n, err := strconv.Atoi(val)
-					if err != nil {
-						notCompatibleType(DisabledItems, value)
-						return false
-					}
-					disabledItems[i] = n
-				}
-			default:
-				if n, ok := isInt(val); ok {
-					disabledItems[i] = n
-				} else {
-					notCompatibleType(DisabledItems, value)
-					return false
-				}
-			}
-
-		}
-		list.disabledItems = disabledItems
-
-	case string:
-		values := strings.Split(value, ",")
-		disabledItems := make([]any, len(values))
-		for i, str := range values {
-			str = strings.Trim(str, " ")
-			if str == "" {
-				notCompatibleType(DisabledItems, value)
-				return false
-			}
-			if isConstantName(str) {
-				disabledItems[i] = str
-			} else {
-				n, err := strconv.Atoi(str)
-				if err != nil {
-					notCompatibleType(DisabledItems, value)
-					return false
-				}
-				disabledItems[i] = n
-			}
-		}
-		list.disabledItems = disabledItems
-
-	case []DataValue:
-		disabledItems := make([]string, 0, len(value))
-		for _, val := range value {
-			if !val.IsObject() {
-				disabledItems = append(disabledItems, val.Value())
-			}
-		}
-		return list.setDisabledItems(disabledItems)
-
-	default:
-		notCompatibleType(DisabledItems, value)
-		return false
-	}
-
-	if list.created {
-		updateInnerHTML(list.htmlID(), list.session)
-	}
-
-	list.propertyChangedEvent(Items)
-	return true
-
-}
-
-func (list *dropDownListData) Get(tag string) any {
-	return list.get(strings.ToLower(tag))
-}
-
-func (list *dropDownListData) get(tag string) any {
-	switch tag {
-	case Items:
-		return list.items
-
-	case DisabledItems:
-		return list.disabledItems
-
-	case Current:
-		result, _ := intProperty(list, Current, list.session, 0)
-		return result
-
-	case DropDownEvent:
-		return list.dropDownListener
-	}
-
-	return list.viewData.get(tag)
-}
-
-func (list *dropDownListData) getItems() []string {
-	return list.items
+	return nil, false
 }
 
 func (list *dropDownListData) htmlTag() string {
@@ -429,11 +194,12 @@ func (list *dropDownListData) htmlTag() string {
 }
 
 func (list *dropDownListData) htmlSubviews(self View, buffer *strings.Builder) {
-	if list.items != nil {
+	if items := GetDropDownItems(list); len(items) > 0 {
 		current := GetCurrent(list)
 		notTranslate := GetNotTranslate(list)
 		disabledItems := GetDropDownDisabledItems(list)
-		for i, item := range list.items {
+		separators := GetDropDownItemSeparators(list)
+		for i, item := range items {
 			disabled := false
 			for _, index := range disabledItems {
 				if i == index {
@@ -455,6 +221,12 @@ func (list *dropDownListData) htmlSubviews(self View, buffer *strings.Builder) {
 
 			buffer.WriteString(item)
 			buffer.WriteString("</option>")
+			for _, index := range separators {
+				if i == index {
+					buffer.WriteString("<hr>")
+					break
+				}
+			}
 		}
 	}
 }
@@ -464,22 +236,21 @@ func (list *dropDownListData) htmlProperties(self View, buffer *strings.Builder)
 	buffer.WriteString(` size="1" onchange="dropDownListEvent(this, event)"`)
 }
 
-func (list *dropDownListData) onSelectedItemChanged(number, old int) {
-	for _, listener := range list.dropDownListener {
-		listener(list, number, old)
-	}
-	list.propertyChangedEvent(Current)
-}
-
-func (list *dropDownListData) handleCommand(self View, command string, data DataObject) bool {
+func (list *dropDownListData) handleCommand(self View, command PropertyName, data DataObject) bool {
 	switch command {
 	case "itemSelected":
 		if text, ok := data.PropertyValue("number"); ok {
 			if number, err := strconv.Atoi(text); err == nil {
-				if GetCurrent(list) != number && number >= 0 && number < len(list.items) {
+				items := GetDropDownItems(list)
+				if GetCurrent(list) != number && number >= 0 && number < len(items) {
 					old := GetCurrent(list)
 					list.properties[Current] = number
-					list.onSelectedItemChanged(number, old)
+					for _, listener := range GetDropDownListeners(list) {
+						listener(list, number, old)
+					}
+					if listener, ok := list.changeListener[Current]; ok {
+						listener(list, Current)
+					}
 				}
 			} else {
 				ErrorLog(err.Error())
@@ -495,32 +266,25 @@ func (list *dropDownListData) handleCommand(self View, command string, data Data
 // GetDropDownListeners returns the "drop-down-event" listener list. If there are no listeners then the empty list is returned.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetDropDownListeners(view View, subviewID ...string) []func(DropDownList, int, int) {
-	return getEventWithOldListeners[DropDownList, int](view, subviewID, DropDownEvent)
+	return getTwoArgEventListeners[DropDownList, int](view, subviewID, DropDownEvent)
 }
 
 // GetDropDownItems return the DropDownList items list.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetDropDownItems(view View, subviewID ...string) []string {
-	if len(subviewID) > 0 && subviewID[0] != "" {
-		view = ViewByID(view, subviewID[0])
-	}
-	if view != nil {
-		if list, ok := view.(DropDownList); ok {
-			return list.getItems()
+	if view = getSubview(view, subviewID); view != nil {
+		if value := view.Get(Items); value != nil {
+			if items, ok := value.([]string); ok {
+				return items
+			}
 		}
 	}
 	return []string{}
 }
 
-// GetDropDownDisabledItems return the list of DropDownList disabled item indexes.
-// If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
-func GetDropDownDisabledItems(view View, subviewID ...string) []int {
-	if len(subviewID) > 0 && subviewID[0] != "" {
-		view = ViewByID(view, subviewID[0])
-	}
-
+func getIndicesArray(view View, tag PropertyName) []int {
 	if view != nil {
-		if value := view.Get(DisabledItems); value != nil {
+		if value := view.Get(tag); value != nil {
 			if values, ok := value.([]any); ok {
 				count := len(values)
 				if count > 0 {
@@ -547,3 +311,17 @@ func GetDropDownDisabledItems(view View, subviewID ...string) []int {
 	}
 	return []int{}
 }
+
+// GetDropDownDisabledItems return an array of disabled(non selectable) items indices of DropDownList.
+// If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
+func GetDropDownDisabledItems(view View, subviewID ...string) []int {
+	view = getSubview(view, subviewID)
+	return getIndicesArray(view, DisabledItems)
+}
+
+// GetDropDownItemSeparators return an array of indices of DropDownList items after which a separator should be added.
+// If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
+func GetDropDownItemSeparators(view View, subviewID ...string) []int {
+	view = getSubview(view, subviewID)
+	return getIndicesArray(view, ItemSeparators)
+}

editView.go

@@ -5,47 +5,103 @@ import (
 	"strings"
 )
 
+// Constants for [EditView] specific properties and events
 const (
-	// EditTextChangedEvent is the constant for the "edit-text-changed" property tag.
-	EditTextChangedEvent = "edit-text-changed"
+	// EditTextChangedEvent is the constant for "edit-text-changed" property tag.
+	//
+	// Used by EditView.
+	// Occur when edit view text has been changed.
+	//
+	// General listener format:
+	//  func(editView rui.EditView, newText string, oldText string).
+	//
+	// where:
+	//   - editView - Interface of an edit view which generated this event,
+	//   - newText - New edit view text,
+	//   - oldText - Previous edit view text.
+	//
+	// Allowed listener formats:
+	//   - func(editView rui.EditView, newText string)
+	//   - func(newText string, oldText string)
+	//   - func(newText string)
+	//   - func(editView rui.EditView)
+	//   - func()
+	EditTextChangedEvent PropertyName = "edit-text-changed"
 
-	// EditViewType is the constant for the "edit-view-type" property tag.
-	EditViewType = "edit-view-type"
+	// EditViewType is the constant for "edit-view-type" property tag.
+	//
+	// Used by EditView.
+	// Type of the text input. Default value is "text".
+	//
+	// Supported types: int, string.
+	//
+	// Values:
+	//   - 0 (SingleLineText) or "text" - One-line text editor.
+	//   - 1 (PasswordText) or "password" - Password editor. The text is hidden by asterisks.
+	//   - 2 (EmailText) or "email" - Single e-mail editor.
+	//   - 3 (EmailsText) or "emails" - Multiple e-mail editor.
+	//   - 4 (URLText) or "url" - Internet address input editor.
+	//   - 5 (PhoneText) or "phone" - Phone number editor.
+	//   - 6 (MultiLineText) or "multiline" - Multi-line text editor.
+	EditViewType PropertyName = "edit-view-type"
 
-	// EditViewPattern is the constant for the "edit-view-pattern" property tag.
-	EditViewPattern = "edit-view-pattern"
+	// EditViewPattern is the constant for "edit-view-pattern" property tag.
+	//
+	// Used by EditView.
+	// Regular expression to limit editing of a text.
+	//
+	// Supported types: string.
+	EditViewPattern PropertyName = "edit-view-pattern"
 
-	// Spellcheck is the constant for the "spellcheck" property tag.
-	Spellcheck = "spellcheck"
+	// Spellcheck is the constant for "spellcheck" property tag.
+	//
+	// Used by EditView.
+	// Enable or disable spell checker. Available in SingleLineText and MultiLineText types of edit view. Default value is
+	// false.
+	//
+	// Supported types: bool, int, string.
+	//
+	// Values:
+	//   - true, 1, "true", "yes", "on", "1" - Enable spell checker for text.
+	//   - false, 0, "false", "no", "off", "0" - Disable spell checker for text.
+	Spellcheck PropertyName = "spellcheck"
 )
 
+// Constants for the values of an [EditView] "edit-view-type" property
 const (
 	// SingleLineText - single-line text type of EditView
 	SingleLineText = 0
+
 	// PasswordText - password type of EditView
 	PasswordText = 1
+
 	// EmailText - e-mail type of EditView. Allows to enter one email
 	EmailText = 2
+
 	// EmailsText - e-mail type of EditView. Allows to enter multiple emails separated by comma
 	EmailsText = 3
+
 	// URLText - url type of EditView. Allows to enter one url
 	URLText = 4
+
 	// PhoneText - telephone type of EditView. Allows to enter one phone number
 	PhoneText = 5
+
 	// MultiLineText - multi-line text type of EditView
 	MultiLineText = 6
 )
 
-// EditView - grid-container of View
+// EditView represent an EditView view
 type EditView interface {
 	View
+
+	// AppendText appends text to the current text of an EditView view
 	AppendText(text string)
+	textChanged(newText, oldText string)
 }
 
 type editViewData struct {
 	viewData
-	dataList
-	textChangeListeners []func(EditView, string, string)
 }
 
 // NewEditView create new EditView object and return it
@@ -57,27 +113,24 @@ func NewEditView(session Session, params Params) EditView {
 }
 
 func newEditView(session Session) View {
-	return NewEditView(session, nil)
+	return new(editViewData) // NewEditView(session, nil)
 }
 
 func (edit *editViewData) init(session Session) {
 	edit.viewData.init(session)
 	edit.hasHtmlDisabled = true
-	edit.textChangeListeners = []func(EditView, string, string){}
 	edit.tag = "EditView"
-	edit.dataListInit()
-}
-
-func (edit *editViewData) String() string {
-	return getViewString(edit, nil)
+	edit.normalize = normalizeEditViewTag
+	edit.set = edit.setFunc
+	edit.changed = edit.propertyChanged
 }
 
 func (edit *editViewData) Focusable() bool {
 	return true
 }
 
-func (edit *editViewData) normalizeTag(tag string) string {
-	tag = strings.ToLower(tag)
+func normalizeEditViewTag(tag PropertyName) PropertyName {
+	tag = defaultNormalize(tag)
 	switch tag {
 	case Type, "edit-type":
 		return EditViewType
@@ -92,279 +145,107 @@ func (edit *editViewData) normalizeTag(tag string) string {
 		return EditWrap
 	}
 
-	return edit.normalizeDataListTag(tag)
+	return normalizeDataListTag(tag)
 }
 
-func (edit *editViewData) Remove(tag string) {
-	edit.remove(edit.normalizeTag(tag))
-}
-
-func (edit *editViewData) remove(tag string) {
-	_, exists := edit.properties[tag]
+func (edit *editViewData) setFunc(tag PropertyName, value any) []PropertyName {
 	switch tag {
-	case Hint:
-		if exists {
-			delete(edit.properties, Hint)
-			if edit.created {
-				edit.session.removeProperty(edit.htmlID(), "placeholder")
-			}
-			edit.propertyChangedEvent(tag)
-		}
-
-	case MaxLength:
-		if exists {
-			delete(edit.properties, MaxLength)
-			if edit.created {
-				edit.session.removeProperty(edit.htmlID(), "maxlength")
-			}
-			edit.propertyChangedEvent(tag)
-		}
-
-	case ReadOnly, Spellcheck:
-		if exists {
-			delete(edit.properties, tag)
-			if edit.created {
-				edit.session.updateProperty(edit.htmlID(), tag, false)
-			}
-			edit.propertyChangedEvent(tag)
-		}
-
-	case EditTextChangedEvent:
-		if len(edit.textChangeListeners) > 0 {
-			edit.textChangeListeners = []func(EditView, string, string){}
-			edit.propertyChangedEvent(tag)
-		}
-
 	case Text:
-		if exists {
-			oldText := GetText(edit)
-			delete(edit.properties, tag)
-			if oldText != "" {
-				edit.textChanged("", oldText)
-				if edit.created {
-					edit.session.callFunc("setInputValue", edit.htmlID(), "")
+		if text, ok := value.(string); ok {
+			old := ""
+			if val := edit.getRaw(Text); val != nil {
+				if txt, ok := val.(string); ok {
+					old = txt
 				}
 			}
+			edit.setRaw("old-text", old)
+			edit.setRaw(tag, text)
+			return []PropertyName{tag}
 		}
 
-	case EditViewPattern:
-		if exists {
-			oldText := GetEditViewPattern(edit)
-			delete(edit.properties, tag)
-			if oldText != "" {
-				if edit.created {
-					edit.session.removeProperty(edit.htmlID(), Pattern)
-				}
-				edit.propertyChangedEvent(tag)
-			}
-		}
+		notCompatibleType(tag, value)
+		return nil
 
-	case EditViewType:
-		if exists {
-			oldType := GetEditViewType(edit)
-			delete(edit.properties, tag)
-			if oldType != 0 {
-				if edit.created {
-					updateInnerHTML(edit.parentHTMLID(), edit.session)
-				}
-				edit.propertyChangedEvent(tag)
-			}
-		}
-
-	case EditWrap:
-		if exists {
-			oldWrap := IsEditViewWrap(edit)
-			delete(edit.properties, tag)
-			if GetEditViewType(edit) == MultiLineText {
-				if wrap := IsEditViewWrap(edit); wrap != oldWrap {
-					if edit.created {
-						if wrap {
-							edit.session.updateProperty(edit.htmlID(), "wrap", "soft")
-						} else {
-							edit.session.updateProperty(edit.htmlID(), "wrap", "off")
-						}
-					}
-					edit.propertyChangedEvent(tag)
-				}
-			}
+	case Hint:
+		if text, ok := value.(string); ok {
+			return setStringPropertyValue(edit, tag, strings.Trim(text, " \t\n"))
 		}
+		notCompatibleType(tag, value)
+		return nil
 
 	case DataList:
-		if len(edit.dataList.dataList) > 0 {
-			edit.setDataList(edit, []string{}, true)
-		}
+		setDataList(edit, value, "")
 
-	default:
-		edit.viewData.remove(tag)
+	case EditTextChangedEvent:
+		return setTwoArgEventListener[EditView, string](edit, tag, value)
 	}
+
+	return edit.viewData.setFunc(tag, value)
 }
 
-func (edit *editViewData) Set(tag string, value any) bool {
-	return edit.set(edit.normalizeTag(tag), value)
-}
-
-func (edit *editViewData) set(tag string, value any) bool {
-	if value == nil {
-		edit.remove(tag)
-		return true
-	}
+func (edit *editViewData) propertyChanged(tag PropertyName) {
+	session := edit.Session()
 
 	switch tag {
 	case Text:
-		if text, ok := value.(string); ok {
-			oldText := GetText(edit)
-			edit.properties[Text] = text
-			if text = GetText(edit); oldText != text {
-				edit.textChanged(text, oldText)
-				if edit.created {
-					edit.session.callFunc("setInputValue", edit.htmlID(), text)
-				}
+		text := GetText(edit)
+		session.callFunc("setInputValue", edit.htmlID(), text)
+
+		old := ""
+		if val := edit.getRaw("old-text"); val != nil {
+			if txt, ok := val.(string); ok {
+				old = txt
 			}
-			return true
 		}
-		return false
+		edit.textChanged(text, old)
 
 	case Hint:
-		if text, ok := value.(string); ok {
-			oldText := GetHint(edit)
-			edit.properties[Hint] = text
-			if text = GetHint(edit); oldText != text {
-				if edit.created {
-					if text != "" {
-						edit.session.updateProperty(edit.htmlID(), "placeholder", text)
-					} else {
-						edit.session.removeProperty(edit.htmlID(), "placeholder")
-					}
-				}
-				edit.propertyChangedEvent(tag)
-			}
-			return true
+		if text := GetHint(edit); text != "" {
+			session.updateProperty(edit.htmlID(), "placeholder", text)
+		} else {
+			session.removeProperty(edit.htmlID(), "placeholder")
 		}
-		return false
 
 	case MaxLength:
-		oldMaxLength := GetMaxLength(edit)
-		if edit.setIntProperty(MaxLength, value) {
-			if maxLength := GetMaxLength(edit); maxLength != oldMaxLength {
-				if edit.created {
-					if maxLength > 0 {
-						edit.session.updateProperty(edit.htmlID(), "maxlength", strconv.Itoa(maxLength))
-					} else {
-						edit.session.removeProperty(edit.htmlID(), "maxlength")
-					}
-				}
-				edit.propertyChangedEvent(tag)
-			}
-			return true
+		if maxLength := GetMaxLength(edit); maxLength > 0 {
+			session.updateProperty(edit.htmlID(), "maxlength", strconv.Itoa(maxLength))
+		} else {
+			session.removeProperty(edit.htmlID(), "maxlength")
 		}
-		return false
 
 	case ReadOnly:
-		if edit.setBoolProperty(ReadOnly, value) {
-			if edit.created {
-				if IsReadOnly(edit) {
-					edit.session.updateProperty(edit.htmlID(), ReadOnly, "")
-				} else {
-					edit.session.removeProperty(edit.htmlID(), ReadOnly)
-				}
-			}
-			edit.propertyChangedEvent(tag)
-			return true
+		if IsReadOnly(edit) {
+			session.updateProperty(edit.htmlID(), "readonly", "")
+		} else {
+			session.removeProperty(edit.htmlID(), "readonly")
 		}
-		return false
 
 	case Spellcheck:
-		if edit.setBoolProperty(Spellcheck, value) {
-			if edit.created {
-				edit.session.updateProperty(edit.htmlID(), Spellcheck, IsSpellcheck(edit))
-			}
-			edit.propertyChangedEvent(tag)
-			return true
-		}
-		return false
+		session.updateProperty(edit.htmlID(), "spellcheck", IsSpellcheck(edit))
 
 	case EditViewPattern:
-		oldText := GetEditViewPattern(edit)
-		if text, ok := value.(string); ok {
-			edit.properties[EditViewPattern] = text
-			if text = GetEditViewPattern(edit); oldText != text {
-				if edit.created {
-					if text != "" {
-						edit.session.updateProperty(edit.htmlID(), Pattern, text)
-					} else {
-						edit.session.removeProperty(edit.htmlID(), Pattern)
-					}
-				}
-				edit.propertyChangedEvent(tag)
-			}
-			return true
+		if text := GetEditViewPattern(edit); text != "" {
+			session.updateProperty(edit.htmlID(), "pattern", text)
+		} else {
+			session.removeProperty(edit.htmlID(), "pattern")
 		}
-		return false
 
 	case EditViewType:
-		oldType := GetEditViewType(edit)
-		if edit.setEnumProperty(EditViewType, value, enumProperties[EditViewType].values) {
-			if GetEditViewType(edit) != oldType {
-				if edit.created {
-					updateInnerHTML(edit.parentHTMLID(), edit.session)
-				}
-				edit.propertyChangedEvent(tag)
-			}
-			return true
-		}
-		return false
+		updateInnerHTML(edit.parentHTMLID(), session)
 
 	case EditWrap:
-		oldWrap := IsEditViewWrap(edit)
-		if edit.setBoolProperty(EditWrap, value) {
-			if GetEditViewType(edit) == MultiLineText {
-				if wrap := IsEditViewWrap(edit); wrap != oldWrap {
-					if edit.created {
-						if wrap {
-							edit.session.updateProperty(edit.htmlID(), "wrap", "soft")
-						} else {
-							edit.session.updateProperty(edit.htmlID(), "wrap", "off")
-						}
-					}
-					edit.propertyChangedEvent(tag)
-				}
-			}
-			return true
+		if wrap := IsEditViewWrap(edit); wrap {
+			session.updateProperty(edit.htmlID(), "wrap", "soft")
+		} else {
+			session.updateProperty(edit.htmlID(), "wrap", "off")
 		}
-		return false
 
 	case DataList:
-		return edit.setDataList(edit, value, edit.created)
+		updateInnerHTML(edit.htmlID(), session)
 
-	case EditTextChangedEvent:
-		listeners, ok := valueToEventWithOldListeners[EditView, string](value)
-		if !ok {
-			notCompatibleType(tag, value)
-			return false
-		} else if listeners == nil {
-			listeners = []func(EditView, string, string){}
-		}
-		edit.textChangeListeners = listeners
-		edit.propertyChangedEvent(tag)
-		return true
+	default:
+		edit.viewData.propertyChanged(tag)
 	}
-
-	return edit.viewData.set(tag, value)
-}
-
-func (edit *editViewData) Get(tag string) any {
-	return edit.get(edit.normalizeTag(tag))
-}
-
-func (edit *editViewData) get(tag string) any {
-	switch tag {
-	case EditTextChangedEvent:
-		return edit.textChangeListeners
-
-	case DataList:
-		return edit.dataList.dataList
-	}
-	return edit.viewData.get(tag)
 }
 
 func (edit *editViewData) AppendText(text string) {
@@ -375,21 +256,24 @@ func (edit *editViewData) AppendText(text string) {
 				textValue += text
 				edit.properties[Text] = textValue
 				edit.session.callFunc("appendToInnerHTML", edit.htmlID(), text)
+				edit.session.callFunc("appendToInputValue", edit.htmlID(), text)
 				edit.textChanged(textValue, oldText)
 				return
 			}
 		}
-		edit.set(Text, text)
+		edit.setRaw(Text, text)
 	} else {
-		edit.set(Text, GetText(edit)+text)
+		edit.setRaw(Text, GetText(edit)+text)
 	}
 }
 
 func (edit *editViewData) textChanged(newText, oldText string) {
-	for _, listener := range edit.textChangeListeners {
+	for _, listener := range GetTextChangedListeners(edit) {
 		listener(edit, newText, oldText)
 	}
-	edit.propertyChangedEvent(Text)
+	if listener, ok := edit.changeListener[Text]; ok {
+		listener(edit, Text)
+	}
 }
 
 func (edit *editViewData) htmlTag() string {
@@ -405,7 +289,9 @@ func (edit *editViewData) htmlSubviews(self View, buffer *strings.Builder) {
 			buffer.WriteString(text)
 		}
 	}
-	edit.dataListHtmlSubviews(self, buffer)
+	dataListHtmlSubviews(self, buffer, func(text string, session Session) string {
+		return text
+	})
 }
 
 func (edit *editViewData) htmlProperties(self View, buffer *strings.Builder) {
@@ -490,16 +376,16 @@ func (edit *editViewData) htmlProperties(self View, buffer *strings.Builder) {
 		}
 	}
 
-	edit.dataListHtmlProperties(edit, buffer)
+	dataListHtmlProperties(edit, buffer)
 }
 
-func (edit *editViewData) handleCommand(self View, command string, data DataObject) bool {
+func (edit *editViewData) handleCommand(self View, command PropertyName, data DataObject) bool {
 	switch command {
 	case "textChanged":
 		oldText := GetText(edit)
 		if text, ok := data.PropertyValue("text"); ok {
-			edit.properties[Text] = text
-			if text := GetText(edit); text != oldText {
+			edit.setRaw(Text, text)
+			if text != oldText {
 				edit.textChanged(text, oldText)
 			}
 		}
@@ -512,10 +398,7 @@ func (edit *editViewData) handleCommand(self View, command string, data DataObje
 // GetText returns a text of the EditView subview.
 // If the second argument (subviewID) is not specified or it is "" then a text of the first argument (view) is returned.
 func GetText(view View, subviewID ...string) string {
-	if len(subviewID) > 0 && subviewID[0] != "" {
-		view = ViewByID(view, subviewID[0])
-	}
-	if view != nil {
+	if view = getSubview(view, subviewID); view != nil {
 		if value := view.getRaw(Text); value != nil {
 			if text, ok := value.(string); ok {
 				return text
@@ -528,9 +411,7 @@ func GetText(view View, subviewID ...string) string {
 // GetHint returns a hint text of the subview.
 // If the second argument (subviewID) is not specified or it is "" then a text of the first argument (view) is returned.
 func GetHint(view View, subviewID ...string) string {
-	if len(subviewID) > 0 && subviewID[0] != "" {
-		view = ViewByID(view, subviewID[0])
-	}
+	view = getSubview(view, subviewID)
 
 	session := view.Session()
 	text := ""
@@ -579,7 +460,7 @@ func IsSpellcheck(view View, subviewID ...string) bool {
 // If there are no listeners then the empty list is returned
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetTextChangedListeners(view View, subviewID ...string) []func(EditView, string, string) {
-	return getEventWithOldListeners[EditView, string](view, subviewID, EditTextChangedEvent)
+	return getTwoArgEventListeners[EditView, string](view, subviewID, EditTextChangedEvent)
 }
 
 // GetEditViewType returns a value of the Type property of EditView.
@@ -591,10 +472,7 @@ func GetEditViewType(view View, subviewID ...string) int {
 // GetEditViewPattern returns a value of the Pattern property of EditView.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetEditViewPattern(view View, subviewID ...string) string {
-	if len(subviewID) > 0 && subviewID[0] != "" {
-		view = ViewByID(view, subviewID[0])
-	}
-	if view != nil {
+	if view = getSubview(view, subviewID); view != nil {
 		if pattern, ok := stringProperty(view, EditViewPattern, view.Session()); ok {
 			return pattern
 		}

events.go

@@ -0,0 +1,517 @@
+package rui
+
+import "strings"
+
+var eventJsFunc = map[PropertyName]struct{ jsEvent, jsFunc string }{
+	FocusEvent:              {jsEvent: "onfocus", jsFunc: "focusEvent"},
+	LostFocusEvent:          {jsEvent: "onblur", jsFunc: "blurEvent"},
+	KeyDownEvent:            {jsEvent: "onkeydown", jsFunc: "keyDownEvent"},
+	KeyUpEvent:              {jsEvent: "onkeyup", jsFunc: "keyUpEvent"},
+	ClickEvent:              {jsEvent: "onclick", jsFunc: "clickEvent"},
+	DoubleClickEvent:        {jsEvent: "ondblclick", jsFunc: "doubleClickEvent"},
+	MouseDown:               {jsEvent: "onmousedown", jsFunc: "mouseDownEvent"},
+	MouseUp:                 {jsEvent: "onmouseup", jsFunc: "mouseUpEvent"},
+	MouseMove:               {jsEvent: "onmousemove", jsFunc: "mouseMoveEvent"},
+	MouseOut:                {jsEvent: "onmouseout", jsFunc: "mouseOutEvent"},
+	MouseOver:               {jsEvent: "onmouseover", jsFunc: "mouseOverEvent"},
+	ContextMenuEvent:        {jsEvent: "oncontextmenu", jsFunc: "contextMenuEvent"},
+	PointerDown:             {jsEvent: "onpointerdown", jsFunc: "pointerDownEvent"},
+	PointerUp:               {jsEvent: "onpointerup", jsFunc: "pointerUpEvent"},
+	PointerMove:             {jsEvent: "onpointermove", jsFunc: "pointerMoveEvent"},
+	PointerCancel:           {jsEvent: "onpointercancel", jsFunc: "pointerCancelEvent"},
+	PointerOut:              {jsEvent: "onpointerout", jsFunc: "pointerOutEvent"},
+	PointerOver:             {jsEvent: "onpointerover", jsFunc: "pointerOverEvent"},
+	TouchStart:              {jsEvent: "ontouchstart", jsFunc: "touchStartEvent"},
+	TouchEnd:                {jsEvent: "ontouchend", jsFunc: "touchEndEvent"},
+	TouchMove:               {jsEvent: "ontouchmove", jsFunc: "touchMoveEvent"},
+	TouchCancel:             {jsEvent: "ontouchcancel", jsFunc: "touchCancelEvent"},
+	TransitionRunEvent:      {jsEvent: "ontransitionrun", jsFunc: "transitionRunEvent"},
+	TransitionStartEvent:    {jsEvent: "ontransitionstart", jsFunc: "transitionStartEvent"},
+	TransitionEndEvent:      {jsEvent: "ontransitionend", jsFunc: "transitionEndEvent"},
+	TransitionCancelEvent:   {jsEvent: "ontransitioncancel", jsFunc: "transitionCancelEvent"},
+	AnimationStartEvent:     {jsEvent: "onanimationstart", jsFunc: "animationStartEvent"},
+	AnimationEndEvent:       {jsEvent: "onanimationend", jsFunc: "animationEndEvent"},
+	AnimationIterationEvent: {jsEvent: "onanimationiteration", jsFunc: "animationIterationEvent"},
+	AnimationCancelEvent:    {jsEvent: "onanimationcancel", jsFunc: "animationCancelEvent"},
+}
+
+func valueToNoArgEventListeners[V any](value any) ([]func(V), bool) {
+	if value == nil {
+		return nil, true
+	}
+
+	switch value := value.(type) {
+	case func(V):
+		return []func(V){value}, true
+
+	case func():
+		fn := func(V) {
+			value()
+		}
+		return []func(V){fn}, true
+
+	case []func(V):
+		if len(value) == 0 {
+			return nil, true
+		}
+		for _, fn := range value {
+			if fn == nil {
+				return nil, false
+			}
+		}
+		return value, true
+
+	case []func():
+		count := len(value)
+		if count == 0 {
+			return nil, true
+		}
+		listeners := make([]func(V), count)
+		for i, v := range value {
+			if v == nil {
+				return nil, false
+			}
+			listeners[i] = func(V) {
+				v()
+			}
+		}
+		return listeners, true
+
+	case []any:
+		count := len(value)
+		if count == 0 {
+			return nil, true
+		}
+		listeners := make([]func(V), count)
+		for i, v := range value {
+			if v == nil {
+				return nil, false
+			}
+			switch v := v.(type) {
+			case func(V):
+				listeners[i] = v
+
+			case func():
+				listeners[i] = func(V) {
+					v()
+				}
+
+			default:
+				return nil, false
+			}
+		}
+		return listeners, true
+	}
+
+	return nil, false
+}
+
+func valueToOneArgEventListeners[V View, E any](value any) ([]func(V, E), bool) {
+	if value == nil {
+		return nil, true
+	}
+
+	switch value := value.(type) {
+	case func(V, E):
+		return []func(V, E){value}, true
+
+	case func(E):
+		fn := func(_ V, event E) {
+			value(event)
+		}
+		return []func(V, E){fn}, true
+
+	case func(V):
+		fn := func(view V, _ E) {
+			value(view)
+		}
+		return []func(V, E){fn}, true
+
+	case func():
+		fn := func(V, E) {
+			value()
+		}
+		return []func(V, E){fn}, true
+
+	case []func(V, E):
+		if len(value) == 0 {
+			return nil, true
+		}
+		for _, fn := range value {
+			if fn == nil {
+				return nil, false
+			}
+		}
+		return value, true
+
+	case []func(E):
+		count := len(value)
+		if count == 0 {
+			return nil, true
+		}
+		listeners := make([]func(V, E), count)
+		for i, v := range value {
+			if v == nil {
+				return nil, false
+			}
+			listeners[i] = func(_ V, event E) {
+				v(event)
+			}
+		}
+		return listeners, true
+
+	case []func(V):
+		count := len(value)
+		if count == 0 {
+			return nil, true
+		}
+		listeners := make([]func(V, E), count)
+		for i, v := range value {
+			if v == nil {
+				return nil, false
+			}
+			listeners[i] = func(view V, _ E) {
+				v(view)
+			}
+		}
+		return listeners, true
+
+	case []func():
+		count := len(value)
+		if count == 0 {
+			return nil, true
+		}
+		listeners := make([]func(V, E), count)
+		for i, v := range value {
+			if v == nil {
+				return nil, false
+			}
+			listeners[i] = func(V, E) {
+				v()
+			}
+		}
+		return listeners, true
+
+	case []any:
+		count := len(value)
+		if count == 0 {
+			return nil, true
+		}
+		listeners := make([]func(V, E), count)
+		for i, v := range value {
+			if v == nil {
+				return nil, false
+			}
+			switch v := v.(type) {
+			case func(V, E):
+				listeners[i] = v
+
+			case func(E):
+				listeners[i] = func(_ V, event E) {
+					v(event)
+				}
+
+			case func(V):
+				listeners[i] = func(view V, _ E) {
+					v(view)
+				}
+
+			case func():
+				listeners[i] = func(V, E) {
+					v()
+				}
+
+			default:
+				return nil, false
+			}
+		}
+		return listeners, true
+	}
+
+	return nil, false
+}
+
+func valueToTwoArgEventListeners[V View, E any](value any) ([]func(V, E, E), bool) {
+	if value == nil {
+		return nil, true
+	}
+
+	switch value := value.(type) {
+	case func(V, E, E):
+		return []func(V, E, E){value}, true
+
+	case func(V, E):
+		fn := func(v V, val, _ E) {
+			value(v, val)
+		}
+		return []func(V, E, E){fn}, true
+
+	case func(E, E):
+		fn := func(_ V, val, old E) {
+			value(val, old)
+		}
+		return []func(V, E, E){fn}, true
+
+	case func(E):
+		fn := func(_ V, val, _ E) {
+			value(val)
+		}
+		return []func(V, E, E){fn}, true
+
+	case func(V):
+		fn := func(v V, _, _ E) {
+			value(v)
+		}
+		return []func(V, E, E){fn}, true
+
+	case func():
+		fn := func(V, E, E) {
+			value()
+		}
+		return []func(V, E, E){fn}, true
+
+	case []func(V, E, E):
+		if len(value) == 0 {
+			return nil, true
+		}
+		for _, fn := range value {
+			if fn == nil {
+				return nil, false
+			}
+		}
+		return value, true
+
+	case []func(V, E):
+		count := len(value)
+		if count == 0 {
+			return nil, true
+		}
+		listeners := make([]func(V, E, E), count)
+		for i, fn := range value {
+			if fn == nil {
+				return nil, false
+			}
+			listeners[i] = func(view V, val, _ E) {
+				fn(view, val)
+			}
+		}
+		return listeners, true
+
+	case []func(E):
+		count := len(value)
+		if count == 0 {
+			return nil, true
+		}
+		listeners := make([]func(V, E, E), count)
+		for i, fn := range value {
+			if fn == nil {
+				return nil, false
+			}
+			listeners[i] = func(_ V, val, _ E) {
+				fn(val)
+			}
+		}
+		return listeners, true
+
+	case []func(E, E):
+		count := len(value)
+		if count == 0 {
+			return nil, true
+		}
+		listeners := make([]func(V, E, E), count)
+		for i, fn := range value {
+			if fn == nil {
+				return nil, false
+			}
+			listeners[i] = func(_ V, val, old E) {
+				fn(val, old)
+			}
+		}
+		return listeners, true
+
+	case []func(V):
+		count := len(value)
+		if count == 0 {
+			return nil, true
+		}
+		listeners := make([]func(V, E, E), count)
+		for i, fn := range value {
+			if fn == nil {
+				return nil, false
+			}
+			listeners[i] = func(view V, _, _ E) {
+				fn(view)
+			}
+		}
+		return listeners, true
+
+	case []func():
+		count := len(value)
+		if count == 0 {
+			return nil, true
+		}
+		listeners := make([]func(V, E, E), count)
+		for i, fn := range value {
+			if fn == nil {
+				return nil, false
+			}
+			listeners[i] = func(V, E, E) {
+				fn()
+			}
+		}
+		return listeners, true
+
+	case []any:
+		count := len(value)
+		if count == 0 {
+			return nil, true
+		}
+		listeners := make([]func(V, E, E), count)
+		for i, v := range value {
+			if v == nil {
+				return nil, false
+			}
+			switch fn := v.(type) {
+			case func(V, E, E):
+				listeners[i] = fn
+
+			case func(V, E):
+				listeners[i] = func(view V, val, _ E) {
+					fn(view, val)
+				}
+
+			case func(E, E):
+				listeners[i] = func(_ V, val, old E) {
+					fn(val, old)
+				}
+
+			case func(E):
+				listeners[i] = func(_ V, val, _ E) {
+					fn(val)
+				}
+
+			case func(V):
+				listeners[i] = func(view V, _, _ E) {
+					fn(view)
+				}
+
+			case func():
+				listeners[i] = func(V, E, E) {
+					fn()
+				}
+
+			default:
+				return nil, false
+			}
+		}
+		return listeners, true
+	}
+
+	return nil, false
+}
+
+func getNoArgEventListeners[V View](view View, subviewID []string, tag PropertyName) []func(V) {
+	if view = getSubview(view, subviewID); view != nil {
+		if value := view.Get(tag); value != nil {
+			if result, ok := value.([]func(V)); ok {
+				return result
+			}
+		}
+	}
+	return []func(V){}
+}
+
+func getOneArgEventListeners[V View, E any](view View, subviewID []string, tag PropertyName) []func(V, E) {
+	if view = getSubview(view, subviewID); view != nil {
+		if value := view.Get(tag); value != nil {
+			if result, ok := value.([]func(V, E)); ok {
+				return result
+			}
+		}
+	}
+	return []func(V, E){}
+}
+
+func getTwoArgEventListeners[V View, E any](view View, subviewID []string, tag PropertyName) []func(V, E, E) {
+	if view = getSubview(view, subviewID); view != nil {
+		if value := view.Get(tag); value != nil {
+			if result, ok := value.([]func(V, E, E)); ok {
+				return result
+			}
+		}
+	}
+	return []func(V, E, E){}
+}
+
+func setNoArgEventListener[V View](properties Properties, tag PropertyName, value any) []PropertyName {
+	if listeners, ok := valueToNoArgEventListeners[V](value); ok {
+		if len(listeners) > 0 {
+			properties.setRaw(tag, listeners)
+		} else if properties.getRaw(tag) != nil {
+			properties.setRaw(tag, nil)
+		} else {
+			return []PropertyName{}
+		}
+		return []PropertyName{tag}
+	}
+	notCompatibleType(tag, value)
+	return nil
+}
+
+func setOneArgEventListener[V View, T any](properties Properties, tag PropertyName, value any) []PropertyName {
+	if listeners, ok := valueToOneArgEventListeners[V, T](value); ok {
+		if len(listeners) > 0 {
+			properties.setRaw(tag, listeners)
+		} else if properties.getRaw(tag) != nil {
+			properties.setRaw(tag, nil)
+		} else {
+			return []PropertyName{}
+		}
+		return []PropertyName{tag}
+	}
+	notCompatibleType(tag, value)
+	return nil
+}
+
+func setTwoArgEventListener[V View, T any](properties Properties, tag PropertyName, value any) []PropertyName {
+	listeners, ok := valueToTwoArgEventListeners[V, T](value)
+	if !ok {
+		notCompatibleType(tag, value)
+		return nil
+	} else if len(listeners) > 0 {
+		properties.setRaw(tag, listeners)
+	} else if properties.getRaw(tag) != nil {
+		properties.setRaw(tag, nil)
+	} else {
+		return []PropertyName{}
+	}
+	return []PropertyName{tag}
+}
+
+func viewEventsHtml[T any](view View, events []PropertyName, buffer *strings.Builder) {
+	for _, tag := range events {
+		if value := view.getRaw(tag); value != nil {
+			if js, ok := eventJsFunc[tag]; ok {
+				if listeners, ok := value.([]func(View, T)); ok && len(listeners) > 0 {
+					buffer.WriteString(js.jsEvent)
+					buffer.WriteString(`="`)
+					buffer.WriteString(js.jsFunc)
+					buffer.WriteString(`(this, event)" `)
+				}
+			}
+		}
+	}
+}
+
+func updateEventListenerHtml(view View, tag PropertyName) {
+	if js, ok := eventJsFunc[tag]; ok {
+		value := view.getRaw(tag)
+		session := view.Session()
+		htmlID := view.htmlID()
+		if value == nil {
+			session.removeProperty(view.htmlID(), js.jsEvent)
+		} else {
+			session.updateProperty(htmlID, js.jsEvent, js.jsFunc+"(this, event)")
+		}
+	}
+}

filePicker.go

@@ -7,31 +7,69 @@ import (
 	"time"
 )
 
+// Constants for [FilePicker] specific properties and events
 const (
 	// FileSelectedEvent is the constant for "file-selected-event" property tag.
-	// The "file-selected-event" is fired when user selects file(s) in the FilePicker.
-	FileSelectedEvent = "file-selected-event"
+	//
+	// Used by FilePicker.
+	// Fired when user selects file(s).
+	//
+	// General listener format:
+	//  func(picker rui.FilePicker, files []rui.FileInfo).
+	//
+	// where:
+	// picker - Interface of a file picker which generated this event,
+	// files - Array of description of selected files.
+	//
+	// Allowed listener formats:
+	//  func(picker rui.FilePicker)
+	//  func(files []rui.FileInfo)
+	//  func()
+	FileSelectedEvent PropertyName = "file-selected-event"
+
 	// Accept is the constant for "accept" property tag.
-	// The "accept" property of the FilePicker sets the list of allowed file extensions or MIME types.
-	Accept = "accept"
+	//
+	// Used by FilePicker.
+	// Set the list of allowed file extensions or MIME types.
+	//
+	// Supported types: string, []string.
+	//
+	// Internal type is string, other types converted to it during assignment.
+	//
+	// Conversion rules:
+	//   - string - may contain single value of multiple separated by comma(,).
+	//   - []string - an array of acceptable file extensions or MIME types.
+	Accept PropertyName = "accept"
+
 	// Multiple is the constant for "multiple" property tag.
-	// The "multiple" bool property of the FilePicker sets whether multiple files can be selected
-	Multiple = "multiple"
+	//
+	// Used by FilePicker.
+	// Controls whether multiple files can be selected.
+	//
+	// Supported types: bool, int, string.
+	//
+	// Values:
+	//   - true, 1, "true", "yes", "on", "1" - Several files can be selected.
+	//   - false, 0, "false", "no", "off", "0" - Only one file can be selected.
+	Multiple PropertyName = "multiple"
 )
 
 // FileInfo describes a file which selected in the FilePicker view
 type FileInfo struct {
 	// Name - the file's name.
 	Name string
+
 	// LastModified specifying the date and time at which the file was last modified
 	LastModified time.Time
+
 	// Size - the size of the file in bytes.
 	Size int64
+
 	// MimeType - the file's MIME type.
 	MimeType string
 }
 
-// FilePicker - the control view for the files selecting
+// FilePicker represents the FilePicker view
 type FilePicker interface {
 	View
 	// Files returns the list of selected files.
@@ -44,9 +82,8 @@ type FilePicker interface {
 
 type filePickerData struct {
 	viewData
-	files                 []FileInfo
-	fileSelectedListeners []func(FilePicker, []FileInfo)
-	loader                map[int]func(FileInfo, []byte)
+	files  []FileInfo
+	loader map[int]func(FileInfo, []byte)
 }
 
 func (file *FileInfo) initBy(node DataValue) {
@@ -77,7 +114,7 @@ func NewFilePicker(session Session, params Params) FilePicker {
 }
 
 func newFilePicker(session Session) View {
-	return NewFilePicker(session, nil)
+	return new(filePickerData) // NewFilePicker(session, nil)
 }
 
 func (picker *filePickerData) init(session Session) {
@@ -86,11 +123,9 @@ func (picker *filePickerData) init(session Session) {
 	picker.hasHtmlDisabled = true
 	picker.files = []FileInfo{}
 	picker.loader = map[int]func(FileInfo, []byte){}
-	picker.fileSelectedListeners = []func(FilePicker, []FileInfo){}
-}
+	picker.set = picker.setFunc
+	picker.changed = picker.propertyChanged
 
-func (picker *filePickerData) String() string {
-	return getViewString(picker, nil)
 }
 
 func (picker *filePickerData) Focusable() bool {
@@ -115,62 +150,16 @@ func (picker *filePickerData) LoadFile(file FileInfo, result func(FileInfo, []by
 	}
 }
 
-func (picker *filePickerData) Remove(tag string) {
-	picker.remove(strings.ToLower(tag))
-}
-
-func (picker *filePickerData) remove(tag string) {
-	switch tag {
-	case FileSelectedEvent:
-		if len(picker.fileSelectedListeners) > 0 {
-			picker.fileSelectedListeners = []func(FilePicker, []FileInfo){}
-			picker.propertyChangedEvent(tag)
-		}
-
-	case Accept:
-		delete(picker.properties, tag)
-		if picker.created {
-			picker.session.removeProperty(picker.htmlID(), "accept")
-		}
-		picker.propertyChangedEvent(tag)
-
-	default:
-		picker.viewData.remove(tag)
-	}
-}
-
-func (picker *filePickerData) Set(tag string, value any) bool {
-	return picker.set(strings.ToLower(tag), value)
-}
-
-func (picker *filePickerData) set(tag string, value any) bool {
-	if value == nil {
-		picker.remove(tag)
-		return true
-	}
+func (picker *filePickerData) setFunc(tag PropertyName, value any) []PropertyName {
 
 	switch tag {
 	case FileSelectedEvent:
-		listeners, ok := valueToEventListeners[FilePicker, []FileInfo](value)
-		if !ok {
-			notCompatibleType(tag, value)
-			return false
-		} else if listeners == nil {
-			listeners = []func(FilePicker, []FileInfo){}
-		}
-		picker.fileSelectedListeners = listeners
-		picker.propertyChangedEvent(tag)
-		return true
+		return setOneArgEventListener[FilePicker, []FileInfo](picker, tag, value)
 
 	case Accept:
 		switch value := value.(type) {
 		case string:
-			value = strings.Trim(value, " \t\n")
-			if value == "" {
-				picker.remove(Accept)
-			} else {
-				picker.properties[Accept] = value
-			}
+			return setStringPropertyValue(picker, Accept, strings.Trim(value, " \t\n"))
 
 		case []string:
 			buffer := allocStringBuilder()
@@ -184,29 +173,27 @@ func (picker *filePickerData) set(tag string, value any) bool {
 					buffer.WriteString(val)
 				}
 			}
-			if buffer.Len() == 0 {
-				picker.remove(Accept)
-			} else {
-				picker.properties[Accept] = buffer.String()
-			}
-
-		default:
-			notCompatibleType(tag, value)
-			return false
+			return setStringPropertyValue(picker, Accept, buffer.String())
 		}
+		notCompatibleType(tag, value)
+		return nil
+	}
 
-		if picker.created {
-			if css := picker.acceptCSS(); css != "" {
-				picker.session.updateProperty(picker.htmlID(), "accept", css)
-			} else {
-				picker.session.removeProperty(picker.htmlID(), "accept")
-			}
+	return picker.viewData.setFunc(tag, value)
+}
+
+func (picker *filePickerData) propertyChanged(tag PropertyName) {
+	switch tag {
+	case Accept:
+		session := picker.Session()
+		if css := acceptPropertyCSS(picker); css != "" {
+			session.updateProperty(picker.htmlID(), "accept", css)
+		} else {
+			session.removeProperty(picker.htmlID(), "accept")
 		}
-		picker.propertyChangedEvent(tag)
-		return true
 
 	default:
-		return picker.viewData.set(tag, value)
+		picker.viewData.propertyChanged(tag)
 	}
 }
 
@@ -214,10 +201,10 @@ func (picker *filePickerData) htmlTag() string {
 	return "input"
 }
 
-func (picker *filePickerData) acceptCSS() string {
-	accept, ok := stringProperty(picker, Accept, picker.Session())
+func acceptPropertyCSS(view View) string {
+	accept, ok := stringProperty(view, Accept, view.Session())
 	if !ok {
-		if value := valueFromStyle(picker, Accept); value != nil {
+		if value := valueFromStyle(view, Accept); value != nil {
 			accept, ok = value.(string)
 		}
 	}
@@ -244,7 +231,7 @@ func (picker *filePickerData) acceptCSS() string {
 func (picker *filePickerData) htmlProperties(self View, buffer *strings.Builder) {
 	picker.viewData.htmlProperties(self, buffer)
 
-	if accept := picker.acceptCSS(); accept != "" {
+	if accept := acceptPropertyCSS(picker); accept != "" {
 		buffer.WriteString(` accept="`)
 		buffer.WriteString(accept)
 		buffer.WriteRune('"')
@@ -261,7 +248,7 @@ func (picker *filePickerData) htmlProperties(self View, buffer *strings.Builder)
 	}
 }
 
-func (picker *filePickerData) handleCommand(self View, command string, data DataObject) bool {
+func (picker *filePickerData) handleCommand(self View, command PropertyName, data DataObject) bool {
 	switch command {
 	case "fileSelected":
 		if node := data.PropertyByTag("files"); node != nil && node.Type() == ArrayNode {
@@ -274,7 +261,7 @@ func (picker *filePickerData) handleCommand(self View, command string, data Data
 			}
 			picker.files = files
 
-			for _, listener := range picker.fileSelectedListeners {
+			for _, listener := range GetFileSelectedListeners(picker) {
 				listener(picker, files)
 			}
 		}
@@ -358,10 +345,7 @@ func IsMultipleFilePicker(view View, subviewID ...string) bool {
 // GetFilePickerAccept returns sets the list of allowed file extensions or MIME types.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetFilePickerAccept(view View, subviewID ...string) []string {
-	if len(subviewID) > 0 && subviewID[0] != "" {
-		view = ViewByID(view, subviewID[0])
-	}
-	if view != nil {
+	if view = getSubview(view, subviewID); view != nil {
 		accept, ok := stringProperty(view, Accept, view.Session())
 		if !ok {
 			if value := valueFromStyle(view, Accept); value != nil {
@@ -383,5 +367,5 @@ func GetFilePickerAccept(view View, subviewID ...string) []string {
 // If there are no listeners then the empty list is returned.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetFileSelectedListeners(view View, subviewID ...string) []func(FilePicker, []FileInfo) {
-	return getEventListeners[FilePicker, []FileInfo](view, subviewID, FileSelectedEvent)
+	return getOneArgEventListeners[FilePicker, []FileInfo](view, subviewID, FileSelectedEvent)
 }

filter.go

@@ -0,0 +1,357 @@
+package rui
+
+import (
+	"fmt"
+	"strings"
+)
+
+// Constants for [FilterProperty] specific properties and events
+const (
+	// Blur is the constant for "blur" property tag.
+	//
+	// Used by FilterProperty.
+	// Applies a Gaussian blur. The value of radius defines the value of the standard deviation to the Gaussian function, or
+	// how many pixels on the screen blend into each other, so a larger value will create more blur. The lacuna value for
+	// interpolation is 0. The parameter is specified as a length in pixels.
+	//
+	// Supported types: float, int, string.
+	//
+	// Internal type is float, other types converted to it during assignment.
+	Blur PropertyName = "blur"
+
+	// Brightness is the constant for "brightness" property tag.
+	//
+	// Used by FilterProperty.
+	// Applies a linear multiplier to input image, making it appear more or less bright. A value of 0% will create an image
+	// that is completely black. A value of 100% leaves the input unchanged. Other values are linear multipliers on the
+	// effect. Values of an amount over 100% are allowed, providing brighter results.
+	//
+	// Supported types: float, int, string.
+	//
+	// Internal type is float, other types converted to it during assignment.
+	Brightness PropertyName = "brightness"
+
+	// Contrast is the constant for "contrast" property tag.
+	//
+	// Used by FilterProperty.
+	// Adjusts the contrast of the input. A value of 0% will create an image that is completely black. A value of 100% leaves
+	// the input unchanged. Values of amount over 100% are allowed, providing results with less contrast.
+	//
+	// Supported types: float, int, string.
+	//
+	// Internal type is float, other types converted to it during assignment.
+	Contrast PropertyName = "contrast"
+
+	// DropShadow is the constant for "drop-shadow" property tag.
+	//
+	// Used by FilterProperty.
+	// Applies a drop shadow effect to the input image. A drop shadow is effectively a blurred, offset version of the input
+	// image's alpha mask drawn in a particular color, composited below the image. Shadow parameters are set using the
+	// ShadowProperty interface.
+	//
+	// Supported types: []ShadowProperty, ShadowProperty, string.
+	//
+	// Internal type is []ShadowProperty, other types converted to it during assignment.
+	// See ShadowProperty description for more details.
+	//
+	// Conversion rules:
+	//   - []ShadowProperty - stored as is, no conversion performed.
+	//   - ShadowProperty - converted to []ShadowProperty.
+	//   - string - string representation of ShadowProperty. Example: "_{blur = 1em, color = black, spread-radius = 0.5em}".
+	DropShadow PropertyName = "drop-shadow"
+
+	// Grayscale is the constant for "grayscale" property tag.
+	//
+	// Used by FilterProperty.
+	// Converts the input image to grayscale. The value of ‘amount’ defines the proportion of the conversion. A value of 100%
+	// is completely grayscale. A value of 0% leaves the input unchanged. Values between 0% and 100% are linear multipliers on
+	// the effect.
+	//
+	// Supported types: float, int, string.
+	//
+	// Internal type is float, other types converted to it during assignment.
+	Grayscale PropertyName = "grayscale"
+
+	// HueRotate is the constant for "hue-rotate" property tag.
+	//
+	// Used by FilterProperty.
+	// Applies a hue rotation on the input image. The value of ‘angle’ defines the number of degrees around the color circle
+	// the input samples will be adjusted. A value of 0deg leaves the input unchanged. If the ‘angle’ parameter is missing, a
+	// value of 0deg is used. Though there is no maximum value, the effect of values above 360deg wraps around.
+	//
+	// Supported types: AngleUnit, string, float, int.
+	//
+	// Internal type is AngleUnit, other types will be converted to it during assignment.
+	// See AngleUnit description for more details.
+	//
+	// Conversion rules:
+	//   - AngleUnit - stored as is, no conversion performed.
+	//   - string - must contain string representation of AngleUnit. If numeric value will be provided without any suffix then AngleUnit with value and Radian value type will be created.
+	//   - float - a new AngleUnit value will be created with Radian as a type.
+	//   - int - a new AngleUnit value will be created with Radian as a type.
+	HueRotate PropertyName = "hue-rotate"
+
+	// Invert is the constant for "invert" property tag.
+	//
+	// Used by FilterProperty.
+	// Inverts the samples in the input image. The value of ‘amount’ defines the proportion of the conversion. A value of 100%
+	// is completely inverted. A value of 0% leaves the input unchanged. Values between 0% and 100% are linear multipliers on
+	// the effect.
+	//
+	// Supported types: float64, int, string.
+	//
+	// Internal type is float, other types converted to it during assignment.
+	Invert PropertyName = "invert"
+
+	// Saturate is the constant for "saturate" property tag.
+	//
+	// Used by FilterProperty.
+	// Saturates the input image. The value of ‘amount’ defines the proportion of the conversion. A value of 0% is completely
+	// un-saturated. A value of 100% leaves the input unchanged. Other values are linear multipliers on the effect. Values of
+	// amount over 100% are allowed, providing super-saturated results.
+	//
+	// Supported types: float, int, string.
+	//
+	// Internal type is float, other types converted to it during assignment.
+	Saturate PropertyName = "saturate"
+
+	// Sepia is the constant for "sepia" property tag.
+	//
+	// Used by FilterProperty.
+	// Converts the input image to sepia. The value of ‘amount’ defines the proportion of the conversion. A value of 100% is
+	// completely sepia. A value of 0% leaves the input unchanged. Values between 0% and 100% are linear multipliers on the
+	// effect.
+	//
+	// Supported types: float, int, string.
+	//
+	// Internal type is float, other types converted to it during assignment.
+	Sepia PropertyName = "sepia"
+)
+
+// FilterProperty defines an applied to a View a graphical effects like blur or color shift.
+// Allowable properties are Blur, Brightness, Contrast, DropShadow, Grayscale, HueRotate, Invert, Opacity, Saturate, and Sepia
+type FilterProperty interface {
+	Properties
+	fmt.Stringer
+	stringWriter
+	cssStyle(session Session) string
+}
+
+type filterData struct {
+	dataProperty
+}
+
+// NewFilterProperty creates the new FilterProperty
+func NewFilterProperty(params Params) FilterProperty {
+	if len(params) > 0 {
+		filter := new(filterData)
+		filter.init()
+		for tag, value := range params {
+			if !filter.Set(tag, value) {
+				return nil
+			}
+		}
+		return filter
+	}
+	return nil
+}
+
+func newFilterProperty(obj DataObject) FilterProperty {
+	filter := new(filterData)
+	filter.init()
+	for i := 0; i < obj.PropertyCount(); i++ {
+		if node := obj.Property(i); node != nil {
+			tag := node.Tag()
+			switch node.Type() {
+			case TextNode:
+				filter.Set(PropertyName(tag), node.Text())
+
+			case ObjectNode:
+				if tag == string(HueRotate) {
+					// TODO
+				} else {
+					ErrorLog(`Invalid value of "` + tag + `"`)
+				}
+
+			default:
+				ErrorLog(`Invalid value of "` + tag + `"`)
+			}
+		}
+	}
+
+	if len(filter.properties) > 0 {
+		return filter
+	}
+	ErrorLog("Empty view filter")
+	return nil
+}
+
+func (filter *filterData) init() {
+	filter.dataProperty.init()
+	filter.set = filterDataSet
+	filter.supportedProperties = []PropertyName{Blur, Brightness, Contrast, Saturate, Grayscale, Invert, Opacity, Sepia, HueRotate, DropShadow}
+}
+
+func filterDataSet(properties Properties, tag PropertyName, value any) []PropertyName {
+	switch tag {
+	case Blur, Brightness, Contrast, Saturate:
+		return setFloatProperty(properties, tag, value, 0, 10000)
+
+	case Grayscale, Invert, Opacity, Sepia:
+		return setFloatProperty(properties, tag, value, 0, 100)
+
+	case HueRotate:
+		return setAngleProperty(properties, tag, value)
+
+	case DropShadow:
+		if setShadowProperty(properties, tag, value) {
+			return []PropertyName{tag}
+		}
+	}
+
+	ErrorLogF(`"%s" property is not supported by the view filter`, tag)
+	return nil
+}
+
+func (filter *filterData) String() string {
+	return runStringWriter(filter)
+}
+
+func (filter *filterData) writeString(buffer *strings.Builder, indent string) {
+	buffer.WriteString("filter { ")
+	comma := false
+	tags := filter.AllTags()
+	for _, tag := range tags {
+		if value, ok := filter.properties[tag]; ok {
+			if comma {
+				buffer.WriteString(", ")
+			}
+			buffer.WriteString(string(tag))
+			buffer.WriteString(" = ")
+			writePropertyValue(buffer, tag, value, indent)
+			comma = true
+		}
+	}
+	buffer.WriteString(" }")
+}
+
+func (filter *filterData) cssStyle(session Session) string {
+	buffer := allocStringBuilder()
+	defer freeStringBuilder(buffer)
+
+	if value, ok := floatTextProperty(filter, Blur, session, 0); ok {
+		buffer.WriteString(string(Blur))
+		buffer.WriteRune('(')
+		buffer.WriteString(value)
+		buffer.WriteString("px)")
+	}
+
+	for _, tag := range []PropertyName{Brightness, Contrast, Saturate, Grayscale, Invert, Opacity, Sepia} {
+		if value, ok := floatTextProperty(filter, tag, session, 0); ok {
+			if buffer.Len() > 0 {
+				buffer.WriteRune(' ')
+			}
+			buffer.WriteString(string(tag))
+			buffer.WriteRune('(')
+			buffer.WriteString(value)
+			buffer.WriteString("%)")
+		}
+	}
+
+	if value, ok := angleProperty(filter, HueRotate, session); ok {
+		if buffer.Len() > 0 {
+			buffer.WriteRune(' ')
+		}
+		buffer.WriteString(string(HueRotate))
+		buffer.WriteRune('(')
+		buffer.WriteString(value.cssString())
+		buffer.WriteRune(')')
+	}
+
+	var lead string
+	if buffer.Len() > 0 {
+		lead = " drop-shadow("
+	} else {
+		lead = "drop-shadow("
+	}
+
+	for _, shadow := range getShadows(filter, DropShadow) {
+		if shadow.cssTextStyle(buffer, session, lead) {
+			buffer.WriteRune(')')
+			lead = " drop-shadow("
+		}
+	}
+
+	return buffer.String()
+}
+
+func setFilterProperty(properties Properties, tag PropertyName, value any) []PropertyName {
+	switch value := value.(type) {
+	case FilterProperty:
+		properties.setRaw(tag, value)
+		return []PropertyName{tag}
+
+	case string:
+		if obj := NewDataObject(value); obj == nil {
+			if filter := newFilterProperty(obj); filter != nil {
+				properties.setRaw(tag, filter)
+				return []PropertyName{tag}
+			}
+		}
+
+	case DataObject:
+		if filter := newFilterProperty(value); filter != nil {
+			properties.setRaw(tag, filter)
+			return []PropertyName{tag}
+		}
+
+	case DataValue:
+		if value.IsObject() {
+			if filter := newFilterProperty(value.Object()); filter != nil {
+				properties.setRaw(tag, filter)
+				return []PropertyName{tag}
+			}
+		}
+	}
+
+	notCompatibleType(tag, value)
+	return nil
+}
+
+// GetFilter returns a View graphical effects like blur or color shift.
+// If the second argument (subviewID) is not specified or it is "" then a top position of the first argument (view) is returned
+func GetFilter(view View, subviewID ...string) FilterProperty {
+	if view = getSubview(view, subviewID); view != nil {
+		if value := view.getRaw(Filter); value != nil {
+			if filter, ok := value.(FilterProperty); ok {
+				return filter
+			}
+		}
+		if value := valueFromStyle(view, Filter); value != nil {
+			if filter, ok := value.(FilterProperty); ok {
+				return filter
+			}
+		}
+	}
+
+	return nil
+}
+
+// GetBackdropFilter returns the area behind a View graphical effects like blur or color shift.
+// If the second argument (subviewID) is not specified or it is "" then a top position of the first argument (view) is returned
+func GetBackdropFilter(view View, subviewID ...string) FilterProperty {
+	if view = getSubview(view, subviewID); view != nil {
+		if value := view.getRaw(BackdropFilter); value != nil {
+			if filter, ok := value.(FilterProperty); ok {
+				return filter
+			}
+		}
+		if value := valueFromStyle(view, BackdropFilter); value != nil {
+			if filter, ok := value.(FilterProperty); ok {
+				return filter
+			}
+		}
+	}
+
+	return nil
+}

focusEvents.go

@@ -2,151 +2,48 @@ package rui
 
 import "strings"
 
+// Constants which represent [View] specific focus events properties
 const (
 	// FocusEvent is the constant for "focus-event" property tag.
-	// The "focus-event" event occurs when the View takes input focus.
-	// The main listener format:
-	//   func(View).
-	// The additional listener format:
-	//   func().
-	FocusEvent = "focus-event"
+	//
+	// Used by View.
+	// Occur when the view takes input focus.
+	//
+	// General listener format:
+	//  func(rui.View).
+	//
+	// where:
+	// view - Interface of a view which generated this event.
+	//
+	// Allowed listener formats:
+	//  func().
+	FocusEvent PropertyName = "focus-event"
 
 	// LostFocusEvent is the constant for "lost-focus-event" property tag.
-	// The "lost-focus-event" event occurs when the View lost input focus.
-	// The main listener format:
-	//   func(View).
-	// The additional listener format:
-	//   func().
-	LostFocusEvent = "lost-focus-event"
+	//
+	// Used by View.
+	// Occur when the View lost input focus.
+	//
+	// General listener format:
+	//  func(view rui.View).
+	//
+	// where:
+	// view - Interface of a view which generated this event.
+	//
+	// Allowed listener formats:
+	//  func()
+	LostFocusEvent PropertyName = "lost-focus-event"
 )
 
-func valueToNoParamListeners[V any](value any) ([]func(V), bool) {
-	if value == nil {
-		return nil, true
-	}
-
-	switch value := value.(type) {
-	case func(V):
-		return []func(V){value}, true
-
-	case func():
-		fn := func(V) {
-			value()
-		}
-		return []func(V){fn}, true
-
-	case []func(V):
-		if len(value) == 0 {
-			return nil, true
-		}
-		for _, fn := range value {
-			if fn == nil {
-				return nil, false
-			}
-		}
-		return value, true
-
-	case []func():
-		count := len(value)
-		if count == 0 {
-			return nil, true
-		}
-		listeners := make([]func(V), count)
-		for i, v := range value {
-			if v == nil {
-				return nil, false
-			}
-			listeners[i] = func(V) {
-				v()
-			}
-		}
-		return listeners, true
-
-	case []any:
-		count := len(value)
-		if count == 0 {
-			return nil, true
-		}
-		listeners := make([]func(V), count)
-		for i, v := range value {
-			if v == nil {
-				return nil, false
-			}
-			switch v := v.(type) {
-			case func(V):
-				listeners[i] = v
-
-			case func():
-				listeners[i] = func(V) {
-					v()
-				}
-
-			default:
-				return nil, false
-			}
-		}
-		return listeners, true
-	}
-
-	return nil, false
-}
-
-var focusEvents = map[string]struct{ jsEvent, jsFunc string }{
-	FocusEvent:     {jsEvent: "onfocus", jsFunc: "focusEvent"},
-	LostFocusEvent: {jsEvent: "onblur", jsFunc: "blurEvent"},
-}
-
-func (view *viewData) setFocusListener(tag string, value any) bool {
-	listeners, ok := valueToNoParamListeners[View](value)
-	if !ok {
-		notCompatibleType(tag, value)
-		return false
-	}
-
-	if listeners == nil {
-		view.removeFocusListener(tag)
-	} else if js, ok := focusEvents[tag]; ok {
-		view.properties[tag] = listeners
-		if view.created {
-			view.session.updateProperty(view.htmlID(), js.jsEvent, js.jsFunc+"(this, event)")
-		}
-	} else {
-		return false
-	}
-	return true
-}
-
-func (view *viewData) removeFocusListener(tag string) {
-	delete(view.properties, tag)
-	if view.created {
-		if js, ok := focusEvents[tag]; ok {
-			view.session.removeProperty(view.htmlID(), js.jsEvent)
-		}
-	}
-}
-
-func getFocusListeners(view View, subviewID []string, tag string) []func(View) {
-	if len(subviewID) > 0 && subviewID[0] != "" {
-		view = ViewByID(view, subviewID[0])
-	}
-
-	if view != nil {
-		if value := view.Get(tag); value != nil {
-			if result, ok := value.([]func(View)); ok {
-				return result
-			}
-		}
-	}
-	return []func(View){}
-}
-
 func focusEventsHtml(view View, buffer *strings.Builder) {
 	if view.Focusable() {
-		for _, js := range focusEvents {
-			buffer.WriteString(js.jsEvent)
-			buffer.WriteString(`="`)
-			buffer.WriteString(js.jsFunc)
-			buffer.WriteString(`(this, event)" `)
+		for _, tag := range []PropertyName{FocusEvent, LostFocusEvent} {
+			if js, ok := eventJsFunc[tag]; ok {
+				buffer.WriteString(js.jsEvent)
+				buffer.WriteString(`="`)
+				buffer.WriteString(js.jsFunc)
+				buffer.WriteString(`(this, event)" `)
+			}
 		}
 	}
 }
@@ -154,11 +51,11 @@ func focusEventsHtml(view View, buffer *strings.Builder) {
 // GetFocusListeners returns a FocusListener list. If there are no listeners then the empty list is returned
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetFocusListeners(view View, subviewID ...string) []func(View) {
-	return getFocusListeners(view, subviewID, FocusEvent)
+	return getNoArgEventListeners[View](view, subviewID, FocusEvent)
 }
 
 // GetLostFocusListeners returns a LostFocusListener list. If there are no listeners then the empty list is returned
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetLostFocusListeners(view View, subviewID ...string) []func(View) {
-	return getFocusListeners(view, subviewID, LostFocusEvent)
+	return getNoArgEventListeners[View](view, subviewID, LostFocusEvent)
 }

go.mod

@@ -2,6 +2,12 @@ module github.com/anoshenko/rui
 
 go 1.18
 
-require github.com/gorilla/websocket v1.5.1
+require (
+	github.com/gorilla/websocket v1.5.1
+	golang.org/x/crypto v0.14.0
+)
 
-require golang.org/x/net v0.17.0 // indirect
+require (
+	golang.org/x/net v0.17.0 // indirect
+	golang.org/x/text v0.13.0 // indirect
+)

go.sum

@@ -1,4 +1,8 @@
 github.com/gorilla/websocket v1.5.1 h1:gmztn0JnHVt9JZquRuzLw3g4wouNVzKL15iLr/zn/QY=
 github.com/gorilla/websocket v1.5.1/go.mod h1:x3kM2JMyaluk02fnUJpQuwD2dCS5NDG2ZHL0uE0tcaY=
+golang.org/x/crypto v0.14.0 h1:wBqGXzWJW6m1XrIKlAH0Hs1JJ7+9KBwnIO8v66Q9cHc=
+golang.org/x/crypto v0.14.0/go.mod h1:MVFd36DqK4CsrnJYDkBA3VC4m2GkXAM0PvzMCn4JQf4=
 golang.org/x/net v0.17.0 h1:pVaXccu2ozPjCXewfr1S7xza/zcXTity9cCdXQYSjIM=
 golang.org/x/net v0.17.0/go.mod h1:NxSsAGuq816PNPmqtQdLE42eU2Fs7NoRIZrHJAlaCOE=
+golang.org/x/text v0.13.0 h1:ablQoSUd0tRdKxZewP80B+BaqeKJuVhuRxj/dkrun3k=
+golang.org/x/text v0.13.0/go.mod h1:TvPlkZtksWOMsz7fbANvkp4WM8x/WCo/om8BMLbz+aE=

gridLayout.go

@@ -5,44 +5,79 @@ import (
 	"strings"
 )
 
+// Constants related to [GridLayout] specific properties and events
 const (
-	// CellVerticalAlign is the constant for the "cell-vertical-align" property tag.
-	// The "cell-vertical-align" int property sets the default vertical alignment
-	// of GridLayout children within the cell they are occupying. Valid values:
-	// * TopAlign (0) / "top"
-	// * BottomAlign (1) / "bottom"
-	// * CenterAlign (2) / "center", and
-	// * StretchAlign (2) / "stretch"
-	CellVerticalAlign = "cell-vertical-align"
+	// CellVerticalAlign is the constant for "cell-vertical-align" property tag.
+	//
+	// Used by GridLayout, SvgImageView.
+	//
+	// Usage in GridLayout:
+	// Sets the default vertical alignment of GridLayout children within the cell they are occupying.
+	//
+	// Supported types: int, string.
+	//
+	// Values:
+	//   - 0 (TopAlign) or "top" - Top alignment.
+	//   - 1 (BottomAlign) or "bottom" - Bottom alignment.
+	//   - 2 (CenterAlign) or "center" - Center alignment.
+	//   - 3 (StretchAlign) or "stretch" - Full height stretch.
+	//
+	// Usage in SvgImageView:
+	// Same as "vertical-align".
+	CellVerticalAlign PropertyName = "cell-vertical-align"
 
-	// CellHorizontalAlign is the constant for the "cell-horizontal-align" property tag.
-	// The "cell-horizontal-align" int property sets the default horizontal alignment
-	// of GridLayout children within the occupied cell. Valid values:
-	// * LeftAlign (0) / "left"
-	// * RightAlign (1) / "right"
-	// * CenterAlign (2) / "center"
-	// * StretchAlign (3) / "stretch"
-	CellHorizontalAlign = "cell-horizontal-align"
+	// CellHorizontalAlign is the constant for "cell-horizontal-align" property tag.
+	//
+	// Used by GridLayout, SvgImageView.
+	//
+	// Usage in GridLayout:
+	// Sets the default horizontal alignment of GridLayout children within the occupied cell.
+	//
+	// Supported types: int, string.
+	//
+	// Values:
+	//   - 0 (LeftAlign) or "left" - Left alignment.
+	//   - 1 (RightAlign) or "right" - Right alignment.
+	//   - 2 (CenterAlign) or "center" - Center alignment.
+	//   - 3 (StretchAlign) or "stretch" - Full width stretch.
+	//
+	// Usage in SvgImageView:
+	// Same as "horizontal-align".
+	CellHorizontalAlign PropertyName = "cell-horizontal-align"
 
-	// CellVerticalSelfAlign is the constant for the "cell-vertical-self-align" property tag.
-	// The "cell-vertical-align" int property sets the vertical alignment of GridLayout children
-	// within the cell they are occupying. The property is set for the child view of GridLayout. Valid values:
-	// * TopAlign (0) / "top"
-	// * BottomAlign (1) / "bottom"
-	// * CenterAlign (2) / "center", and
-	// * StretchAlign (2) / "stretch"
-	CellVerticalSelfAlign = "cell-vertical-self-align"
+	// CellVerticalSelfAlign is the constant for "cell-vertical-self-align" property tag.
+	//
+	// Used by GridLayout.
+	// Sets the vertical alignment of GridLayout children within the cell they are occupying. The property is set for the
+	// child view of GridLayout.
+	//
+	// Supported types: int, string.
+	//
+	// Values:
+	//   - 0 (TopAlign) or "top" - Top alignment.
+	//   - 1 (BottomAlign) or "bottom" - Bottom alignment.
+	//   - 2 (CenterAlign) or "center" - Center alignment.
+	//   - 3 (StretchAlign) or "stretch" - Full height stretch.
+	CellVerticalSelfAlign PropertyName = "cell-vertical-self-align"
 
-	// CellHorizontalSelfAlign is the constant for the "cell-horizontal-self-align" property tag.
-	// The "cell-horizontal-self align" int property sets the horizontal alignment of GridLayout children
-	// within the occupied cell. The property is set for the child view of GridLayout. Valid values:
-	// * LeftAlign (0) / "left"
-	// * RightAlign (1) / "right"
-	// * CenterAlign (2) / "center"
-	// * StretchAlign (3) / "stretch"
-	CellHorizontalSelfAlign = "cell-horizontal-self-align"
+	// CellHorizontalSelfAlign is the constant for "cell-horizontal-self-align" property tag.
+	//
+	// Used by GridLayout.
+	// Sets the horizontal alignment of GridLayout children within the occupied cell. The property is set for the child view
+	// of GridLayout.
+	//
+	// Supported types: int, string.
+	//
+	// Values:
+	//   - 0 (LeftAlign) or "left" - Left alignment.
+	//   - 1 (RightAlign) or "right" - Right alignment.
+	//   - 2 (CenterAlign) or "center" - Center alignment.
+	//   - 3 (StretchAlign) or "stretch" - Full width stretch.
+	CellHorizontalSelfAlign PropertyName = "cell-horizontal-self-align"
 )
 
+// GridAdapter is an interface to define [GridLayout] content. [GridLayout] will query interface functions to populate
+// its content
 type GridAdapter interface {
 	// GridColumnCount returns the number of columns in the grid
 	GridColumnCount() int
@@ -54,21 +89,21 @@ type GridAdapter interface {
 	GridCellContent(row, column int, session Session) View
 }
 
-// GridCellColumnSpanAdapter implements the optional method of GridAdapter interface
+// GridCellColumnSpanAdapter implements the optional method of the [GridAdapter] interface
 type GridCellColumnSpanAdapter interface {
 	// GridCellColumnSpan returns the number of columns that a cell spans.
 	// Values ​​less than 1 are ignored.
 	GridCellColumnSpan(row, column int) int
 }
 
-// GridCellColumnSpanAdapter implements the optional method of GridAdapter interface
+// GridCellColumnSpanAdapter implements the optional method of the [GridAdapter] interface
 type GridCellRowSpanAdapter interface {
 	// GridCellRowSpan returns the number of rows that a cell spans
 	// Values ​​less than 1 are ignored.
 	GridCellRowSpan(row, column int) int
 }
 
-// GridLayout - grid-container of View
+// GridLayout represents a GridLayout view
 type GridLayout interface {
 	ViewsContainer
 
@@ -91,7 +126,8 @@ func NewGridLayout(session Session, params Params) GridLayout {
 }
 
 func newGridLayout(session Session) View {
-	return NewGridLayout(session, nil)
+	//return NewGridLayout(session, nil)
+	return new(gridLayoutData)
 }
 
 // Init initialize fields of GridLayout by default values
@@ -100,13 +136,14 @@ func (gridLayout *gridLayoutData) init(session Session) {
 	gridLayout.tag = "GridLayout"
 	gridLayout.systemClass = "ruiGridLayout"
 	gridLayout.adapter = nil
+	gridLayout.normalize = normalizeGridLayoutTag
+	gridLayout.get = gridLayout.getFunc
+	gridLayout.set = gridLayout.setFunc
+	gridLayout.remove = gridLayout.removeFunc
+	gridLayout.changed = gridLayout.propertyChanged
 }
 
-func (gridLayout *gridLayoutData) String() string {
-	return getViewString(gridLayout, nil)
-}
-
-func (style *viewStyle) setGridCellSize(tag string, value any) bool {
+func setGridCellSize(properties Properties, tag PropertyName, value any) []PropertyName {
 	setValues := func(values []string) bool {
 		count := len(values)
 		if count > 1 {
@@ -124,11 +161,11 @@ func (style *viewStyle) setGridCellSize(tag string, value any) bool {
 					return false
 				}
 			}
-			style.properties[tag] = sizes
+			properties.setRaw(tag, sizes)
 		} else if isConstantName(values[0]) {
-			style.properties[tag] = values[0]
+			properties.setRaw(tag, values[0])
 		} else if size, err := stringToSizeUnit(values[0]); err == nil {
-			style.properties[tag] = size
+			properties.setRaw(tag, size)
 		} else {
 			invalidPropertyValue(tag, value)
 			return false
@@ -140,41 +177,41 @@ func (style *viewStyle) setGridCellSize(tag string, value any) bool {
 	case CellWidth, CellHeight:
 		switch value := value.(type) {
 		case SizeUnit, []SizeUnit:
-			style.properties[tag] = value
+			properties.setRaw(tag, value)
 
 		case string:
 			if !setValues(strings.Split(value, ",")) {
-				return false
+				return nil
 			}
 
 		case []string:
 			if !setValues(value) {
-				return false
+				return nil
 			}
 
 		case []DataValue:
 			count := len(value)
 			if count == 0 {
 				invalidPropertyValue(tag, value)
-				return false
+				return nil
 			}
 			values := make([]string, count)
 			for i, val := range value {
 				if val.IsObject() {
 					invalidPropertyValue(tag, value)
-					return false
+					return nil
 				}
 				values[i] = val.Value()
 			}
 			if !setValues(values) {
-				return false
+				return nil
 			}
 
 		case []any:
 			count := len(value)
 			if count == 0 {
 				invalidPropertyValue(tag, value)
-				return false
+				return nil
 			}
 			sizes := make([]any, count)
 			for i, val := range value {
@@ -189,29 +226,29 @@ func (style *viewStyle) setGridCellSize(tag string, value any) bool {
 						sizes[i] = size
 					} else {
 						invalidPropertyValue(tag, value)
-						return false
+						return nil
 					}
 
 				default:
 					invalidPropertyValue(tag, value)
-					return false
+					return nil
 				}
 			}
-			style.properties[tag] = sizes
+			properties.setRaw(tag, sizes)
 
 		default:
 			notCompatibleType(tag, value)
-			return false
+			return nil
 		}
 
-		return true
+		return []PropertyName{tag}
 	}
 
-	return false
+	return nil
 }
 
-func (style *viewStyle) gridCellSizesCSS(tag string, session Session) string {
-	switch cellSize := gridCellSizes(style, tag, session); len(cellSize) {
+func gridCellSizesCSS(properties Properties, tag PropertyName, session Session) string {
+	switch cellSize := gridCellSizes(properties, tag, session); len(cellSize) {
 	case 0:
 
 	case 1:
@@ -248,8 +285,8 @@ func (style *viewStyle) gridCellSizesCSS(tag string, session Session) string {
 	return ""
 }
 
-func (gridLayout *gridLayoutData) normalizeTag(tag string) string {
-	tag = strings.ToLower(tag)
+func normalizeGridLayoutTag(tag PropertyName) PropertyName {
+	tag = defaultNormalize(tag)
 	switch tag {
 	case VerticalAlign:
 		return CellVerticalAlign
@@ -266,162 +303,169 @@ func (gridLayout *gridLayoutData) normalizeTag(tag string) string {
 	return tag
 }
 
-func (gridLayout *gridLayoutData) Get(tag string) any {
-	return gridLayout.get(gridLayout.normalizeTag(tag))
-}
-
-func (gridLayout *gridLayoutData) get(tag string) any {
-	if tag == Gap {
+func (gridLayout *gridLayoutData) getFunc(tag PropertyName) any {
+	switch tag {
+	case Gap:
 		rowGap := GetGridRowGap(gridLayout)
 		columnGap := GetGridColumnGap(gridLayout)
 		if rowGap.Equal(columnGap) {
 			return rowGap
 		}
 		return AutoSize()
-	}
-
-	return gridLayout.viewsContainerData.get(tag)
-}
-
-func (gridLayout *gridLayoutData) Remove(tag string) {
-	gridLayout.remove(gridLayout.normalizeTag(tag))
-}
-
-func (gridLayout *gridLayoutData) remove(tag string) {
-	switch tag {
-	case Gap:
-		gridLayout.remove(GridRowGap)
-		gridLayout.remove(GridColumnGap)
-		gridLayout.propertyChangedEvent(Gap)
-		return
 
 	case Content:
-		gridLayout.adapter = nil
-	}
-
-	gridLayout.viewsContainerData.remove(tag)
-
-	if gridLayout.created {
-		switch tag {
-		case CellWidth:
-			gridLayout.session.updateCSSProperty(gridLayout.htmlID(), `grid-template-columns`,
-				gridLayout.gridCellSizesCSS(CellWidth, gridLayout.session))
-
-		case CellHeight:
-			gridLayout.session.updateCSSProperty(gridLayout.htmlID(), `grid-template-rows`,
-				gridLayout.gridCellSizesCSS(CellHeight, gridLayout.session))
-
+		if gridLayout.adapter != nil {
+			return gridLayout.adapter
 		}
 	}
+
+	return gridLayout.viewsContainerData.getFunc(tag)
 }
 
-func (gridLayout *gridLayoutData) Set(tag string, value any) bool {
-	return gridLayout.set(gridLayout.normalizeTag(tag), value)
-}
-
-func (gridLayout *gridLayoutData) set(tag string, value any) bool {
-	if value == nil {
-		gridLayout.remove(tag)
-		return true
-	}
-
+func (gridLayout *gridLayoutData) removeFunc(tag PropertyName) []PropertyName {
 	switch tag {
 	case Gap:
-		return gridLayout.set(GridRowGap, value) && gridLayout.set(GridColumnGap, value)
+		result := []PropertyName{}
+		for _, tag := range []PropertyName{GridRowGap, GridColumnGap} {
+			if gridLayout.getRaw(tag) != nil {
+				gridLayout.setRaw(tag, nil)
+				result = append(result, tag)
+			}
+		}
+		return result
+
+	case Content:
+		if len(gridLayout.views) > 0 || gridLayout.adapter != nil {
+			gridLayout.views = []View{}
+			gridLayout.adapter = nil
+			return []PropertyName{Content}
+		}
+		return []PropertyName{}
+	}
+
+	return gridLayout.viewsContainerData.removeFunc(tag)
+}
+
+func (gridLayout *gridLayoutData) setFunc(tag PropertyName, value any) []PropertyName {
+	switch tag {
+	case Gap:
+		result := gridLayout.setFunc(GridRowGap, value)
+		if result != nil {
+			if gap := gridLayout.getRaw(GridRowGap); gap != nil {
+				gridLayout.setRaw(GridColumnGap, gap)
+				result = append(result, GridColumnGap)
+			}
+		}
+		return result
 
 	case Content:
 		if adapter, ok := value.(GridAdapter); ok {
 			gridLayout.adapter = adapter
-			gridLayout.UpdateGridContent()
-			return true
+			gridLayout.createGridContent()
+		} else if gridLayout.setContent(value) {
+			gridLayout.adapter = nil
+		} else {
+			return nil
 		}
-		gridLayout.adapter = nil
+		return []PropertyName{Content}
 	}
 
-	if gridLayout.viewsContainerData.set(tag, value) {
-		if gridLayout.created {
-			switch tag {
-			case CellWidth:
-				gridLayout.session.updateCSSProperty(gridLayout.htmlID(), `grid-template-columns`,
-					gridLayout.gridCellSizesCSS(CellWidth, gridLayout.session))
+	return gridLayout.viewsContainerData.setFunc(tag, value)
+}
 
-			case CellHeight:
-				gridLayout.session.updateCSSProperty(gridLayout.htmlID(), `grid-template-rows`,
-					gridLayout.gridCellSizesCSS(CellHeight, gridLayout.session))
+func (gridLayout *gridLayoutData) propertyChanged(tag PropertyName) {
+	switch tag {
+	case CellWidth:
+		session := gridLayout.Session()
+		session.updateCSSProperty(gridLayout.htmlID(), `grid-template-columns`,
+			gridCellSizesCSS(gridLayout, CellWidth, session))
 
+	case CellHeight:
+		session := gridLayout.Session()
+		session.updateCSSProperty(gridLayout.htmlID(), `grid-template-rows`,
+			gridCellSizesCSS(gridLayout, CellHeight, session))
+
+	default:
+		gridLayout.viewsContainerData.propertyChanged(tag)
+	}
+}
+
+func (gridLayout *gridLayoutData) createGridContent() bool {
+	if gridLayout.adapter == nil {
+		return false
+	}
+
+	adapter := gridLayout.adapter
+	gridLayout.views = []View{}
+
+	session := gridLayout.session
+	htmlID := gridLayout.htmlID()
+	isDisabled := IsDisabled(gridLayout)
+
+	var columnSpan GridCellColumnSpanAdapter = nil
+	if span, ok := adapter.(GridCellColumnSpanAdapter); ok {
+		columnSpan = span
+	}
+
+	var rowSpan GridCellRowSpanAdapter = nil
+	if span, ok := adapter.(GridCellRowSpanAdapter); ok {
+		rowSpan = span
+	}
+
+	width := adapter.GridColumnCount()
+	height := adapter.GridRowCount()
+	for column := 0; column < width; column++ {
+		for row := 0; row < height; row++ {
+			if view := adapter.GridCellContent(row, column, session); view != nil {
+				view.setParentID(htmlID)
+
+				columnCount := 1
+				if columnSpan != nil {
+					columnCount = columnSpan.GridCellColumnSpan(row, column)
+				}
+
+				if columnCount > 1 {
+					view.Set(Column, Range{First: column, Last: column + columnCount - 1})
+				} else {
+					view.Set(Column, column)
+				}
+
+				rowCount := 1
+				if rowSpan != nil {
+					rowCount = rowSpan.GridCellRowSpan(row, column)
+				}
+
+				if rowCount > 1 {
+					view.Set(Row, Range{First: row, Last: row + rowCount - 1})
+				} else {
+					view.Set(Row, row)
+				}
+
+				if isDisabled {
+					view.Set(Disabled, true)
+				}
+
+				gridLayout.views = append(gridLayout.views, view)
 			}
 		}
-		return true
 	}
 
-	return false
+	return true
 }
 
 func (gridLayout *gridLayoutData) UpdateGridContent() {
-	if adapter := gridLayout.adapter; adapter != nil {
-		gridLayout.views = []View{}
-
-		session := gridLayout.session
-		htmlID := gridLayout.htmlID()
-		isDisabled := IsDisabled(gridLayout)
-
-		var columnSpan GridCellColumnSpanAdapter = nil
-		if span, ok := adapter.(GridCellColumnSpanAdapter); ok {
-			columnSpan = span
-		}
-
-		var rowSpan GridCellRowSpanAdapter = nil
-		if span, ok := adapter.(GridCellRowSpanAdapter); ok {
-			rowSpan = span
-		}
-
-		width := adapter.GridColumnCount()
-		height := adapter.GridRowCount()
-		for column := 0; column < width; column++ {
-			for row := 0; row < height; row++ {
-				if view := adapter.GridCellContent(row, column, session); view != nil {
-					view.setParentID(htmlID)
-
-					columnCount := 1
-					if columnSpan != nil {
-						columnCount = columnSpan.GridCellColumnSpan(row, column)
-					}
-
-					if columnCount > 1 {
-						view.Set(Column, Range{First: column, Last: column + columnCount - 1})
-					} else {
-						view.Set(Column, column)
-					}
-
-					rowCount := 1
-					if rowSpan != nil {
-						rowCount = rowSpan.GridCellRowSpan(row, column)
-					}
-
-					if rowCount > 1 {
-						view.Set(Row, Range{First: row, Last: row + rowCount - 1})
-					} else {
-						view.Set(Row, row)
-					}
-
-					if isDisabled {
-						view.Set(Disabled, true)
-					}
-
-					gridLayout.views = append(gridLayout.views, view)
-				}
-			}
-		}
-
+	if gridLayout.createGridContent() {
 		if gridLayout.created {
-			updateInnerHTML(htmlID, session)
+			updateInnerHTML(gridLayout.htmlID(), gridLayout.session)
 		}
 
-		gridLayout.propertyChangedEvent(Content)
+		if listener, ok := gridLayout.changeListener[Content]; ok {
+			listener(gridLayout, Content)
+		}
 	}
 }
 
-func gridCellSizes(properties Properties, tag string, session Session) []SizeUnit {
+func gridCellSizes(properties Properties, tag PropertyName, session Session) []SizeUnit {
 	if value := properties.Get(tag); value != nil {
 		switch value := value.(type) {
 		case []SizeUnit:
@@ -461,12 +505,6 @@ func gridCellSizes(properties Properties, tag string, session Session) []SizeUni
 	return []SizeUnit{}
 }
 
-/*
-func (gridLayout *gridLayoutData) cssStyle(self View, builder cssBuilder) {
-	gridLayout.viewsContainerData.cssStyle(self, builder)
-}
-*/
-
 // GetCellVerticalAlign returns the vertical align of a GridLayout cell content: TopAlign (0), BottomAlign (1), CenterAlign (2), StretchAlign (3)
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetCellVerticalAlign(view View, subviewID ...string) int {
@@ -489,10 +527,7 @@ func GetGridAutoFlow(view View, subviewID ...string) int {
 // If the result is a single value array, then the width of all cell is equal.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetCellWidth(view View, subviewID ...string) []SizeUnit {
-	if len(subviewID) > 0 && subviewID[0] != "" {
-		view = ViewByID(view, subviewID[0])
-	}
-	if view != nil {
+	if view = getSubview(view, subviewID); view != nil {
 		return gridCellSizes(view, CellWidth, view.Session())
 	}
 	return []SizeUnit{}
@@ -502,10 +537,7 @@ func GetCellWidth(view View, subviewID ...string) []SizeUnit {
 // If the result is a single value array, then the height of all cell is equal.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetCellHeight(view View, subviewID ...string) []SizeUnit {
-	if len(subviewID) > 0 && subviewID[0] != "" {
-		view = ViewByID(view, subviewID[0])
-	}
-	if view != nil {
+	if view = getSubview(view, subviewID); view != nil {
 		return gridCellSizes(view, CellHeight, view.Session())
 	}
 	return []SizeUnit{}

httpHandler.go

@@ -1,3 +1,5 @@
+//go:build !wasm
+
 package rui
 
 import (
@@ -20,25 +22,24 @@ func (h *httpHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 	}
 }
 
-/*
-NewHandler is used to embed the rui application in third-party web frameworks (net/http, gin, echo...).
-Example for echo:
-
-	e := echo.New()
-	e.Any(`/ui/*`, func()echo.HandlerFunc{
-		rui.AddEmbedResources(&resources)
-
-		h := rui.NewHandler("/ui", CreateSessionContent, rui.AppParams{
-			Title: `Awesome app`,
-			Icon: `favicon.png`,
-		})
-
-		return func(c echo.Context) error {
-			h.ServeHTTP(c.Response(), c.Request())
-			return nil
-		}
-	})
-*/
+// NewHandler is used to embed the rui application in third-party web frameworks (net/http, gin, echo...).
+//
+// Example for echo:
+//
+//	e := echo.New()
+//	e.Any(`/ui/*`, func()echo.HandlerFunc{
+//		rui.AddEmbedResources(&resources)
+//
+//		h := rui.NewHandler("/ui", CreateSessionContent, rui.AppParams{
+//			Title: `Awesome app`,
+//			Icon: `favicon.png`,
+//		})
+//
+//		return func(c echo.Context) error {
+//			h.ServeHTTP(c.Response(), c.Request())
+//			return nil
+//		}
+//	})
 func NewHandler(urlPrefix string, createContentFunc func(Session) SessionContent, params AppParams) *httpHandler {
 	app := new(application)
 	app.params = params

image.go

@@ -4,6 +4,7 @@ import (
 	"strconv"
 )
 
+// Constants which represent return values of the LoadingStatus function of an [Image] view
 const (
 	// ImageLoading is the image loading status: in the process of loading
 	ImageLoading = 0

imageView.go

@@ -5,35 +5,63 @@ import (
 	"strings"
 )
 
+// Constants which represent [ImageView] specific properties and events
 const (
-	// LoadedEvent is the constant for the "loaded-event" property tag.
-	// The "loaded-event" event occurs event occurs when the image has been loaded.
-	LoadedEvent = "loaded-event"
-	// ErrorEvent is the constant for the "error-event" property tag.
-	// The "error-event" event occurs event occurs when the image loading failed.
-	ErrorEvent = "error-event"
+	// LoadedEvent is the constant for "loaded-event" property tag.
+	//
+	// Used by ImageView.
+	// Occur when the image has been loaded.
+	//
+	// General listener format:
+	//  func(image rui.ImageView)
+	//
+	// where:
+	// image - Interface of an image view which generated this event.
+	//
+	// Allowed listener formats:
+	//  func()
+	LoadedEvent PropertyName = "loaded-event"
+
+	// ErrorEvent is the constant for "error-event" property tag.
+	//
+	// Used by ImageView.
+	// Occur when the image loading has been failed.
+	//
+	// General listener format:
+	//  func(image rui.ImageView)
+	//
+	// where:
+	// image - Interface of an image view which generated this event.
+	//
+	// Allowed listener formats:
+	//  func()
+	ErrorEvent PropertyName = "error-event"
 
 	// NoneFit - value of the "object-fit" property of an ImageView. The replaced content is not resized
 	NoneFit = 0
+
 	// ContainFit - value of the "object-fit" property of an ImageView. The replaced content
 	// is scaled to maintain its aspect ratio while fitting within the element’s content box.
 	// The entire object is made to fill the box, while preserving its aspect ratio, so the object
 	// will be "letterboxed" if its aspect ratio does not match the aspect ratio of the box.
 	ContainFit = 1
+
 	// CoverFit - value of the "object-fit" property of an ImageView. The replaced content
 	// is sized to maintain its aspect ratio while filling the element’s entire content box.
 	// If the object's aspect ratio does not match the aspect ratio of its box, then the object will be clipped to fit.
 	CoverFit = 2
+
 	// FillFit - value of the "object-fit" property of an ImageView. The replaced content is sized
 	// to fill the element’s content box. The entire object will completely fill the box.
 	// If the object's aspect ratio does not match the aspect ratio of its box, then the object will be stretched to fit.
 	FillFit = 3
+
 	// ScaleDownFit - value of the "object-fit" property of an ImageView. The content is sized as
 	// if NoneFit or ContainFit were specified, whichever would result in a smaller concrete object size.
 	ScaleDownFit = 4
 )
 
-// ImageView - image View
+// ImageView represents an ImageView view
 type ImageView interface {
 	View
 	// NaturalSize returns the intrinsic, density-corrected size (width, height) of the image in pixels.
@@ -60,7 +88,7 @@ func NewImageView(session Session, params Params) ImageView {
 }
 
 func newImageView(session Session) View {
-	return NewImageView(session, nil)
+	return new(imageViewData)
 }
 
 // Init initialize fields of imageView by default values
@@ -68,14 +96,13 @@ func (imageView *imageViewData) init(session Session) {
 	imageView.viewData.init(session)
 	imageView.tag = "ImageView"
 	imageView.systemClass = "ruiImageView"
+	imageView.normalize = normalizeImageViewTag
+	imageView.set = imageView.setFunc
+	imageView.changed = imageView.propertyChanged
 }
 
-func (imageView *imageViewData) String() string {
-	return getViewString(imageView, nil)
-}
-
-func (imageView *imageViewData) normalizeTag(tag string) string {
-	tag = strings.ToLower(tag)
+func normalizeImageViewTag(tag PropertyName) PropertyName {
+	tag = defaultNormalize(tag)
 	switch tag {
 	case "source":
 		tag = Source
@@ -95,127 +122,58 @@ func (imageView *imageViewData) normalizeTag(tag string) string {
 	return tag
 }
 
-func (imageView *imageViewData) Remove(tag string) {
-	imageView.remove(imageView.normalizeTag(tag))
-}
+func (imageView *imageViewData) setFunc(tag PropertyName, value any) []PropertyName {
 
-func (imageView *imageViewData) remove(tag string) {
-	imageView.viewData.remove(tag)
-	if imageView.created {
-		switch tag {
-		case Source:
-			imageView.session.updateProperty(imageView.htmlID(), "src", "")
-			imageView.session.removeProperty(imageView.htmlID(), "srcset")
-
-		case AltText:
-			updateInnerHTML(imageView.htmlID(), imageView.session)
-
-		case ImageVerticalAlign, ImageHorizontalAlign:
-			updateCSSStyle(imageView.htmlID(), imageView.session)
+	switch tag {
+	case Source, SrcSet, AltText:
+		if text, ok := value.(string); ok {
+			return setStringPropertyValue(imageView, tag, text)
 		}
+		notCompatibleType(tag, value)
+		return nil
+
+	case LoadedEvent, ErrorEvent:
+		return setNoArgEventListener[ImageView](imageView, tag, value)
 	}
+
+	return imageView.viewData.setFunc(tag, value)
 }
 
-func (imageView *imageViewData) Set(tag string, value any) bool {
-	return imageView.set(imageView.normalizeTag(tag), value)
-}
-
-func (imageView *imageViewData) set(tag string, value any) bool {
-	if value == nil {
-		imageView.remove(tag)
-		return true
-	}
+func (imageView *imageViewData) propertyChanged(tag PropertyName) {
+	session := imageView.Session()
+	htmlID := imageView.htmlID()
 
 	switch tag {
 	case Source:
-		if text, ok := value.(string); ok {
-			imageView.properties[tag] = text
-			if imageView.created {
-				src, srcset := imageView.src(text)
-				imageView.session.updateProperty(imageView.htmlID(), "src", src)
-
-				if srcset != "" {
-					imageView.session.updateProperty(imageView.htmlID(), "srcset", srcset)
-				} else {
-					imageView.session.removeProperty(imageView.htmlID(), "srcset")
-				}
-			}
-			imageView.propertyChangedEvent(Source)
-			return true
+		src, srcset := imageViewSrc(imageView, GetImageViewSource(imageView))
+		session.updateProperty(htmlID, "src", src)
+		if srcset != "" {
+			session.updateProperty(htmlID, "srcset", srcset)
+		} else {
+			session.removeProperty(htmlID, "srcset")
 		}
-		notCompatibleType(Source, value)
 
 	case SrcSet:
-		if text, ok := value.(string); ok {
-			if text == "" {
-				delete(imageView.properties, tag)
-			} else {
-				imageView.properties[tag] = text
-			}
-			if imageView.created {
-				_, srcset := imageView.src(text)
-				if srcset != "" {
-					imageView.session.updateProperty(imageView.htmlID(), "srcset", srcset)
-				} else {
-					imageView.session.removeProperty(imageView.htmlID(), "srcset")
-				}
-			}
-			imageView.propertyChangedEvent(Source)
-			return true
+		_, srcset := imageViewSrc(imageView, GetImageViewSource(imageView))
+		if srcset != "" {
+			session.updateProperty(htmlID, "srcset", srcset)
+		} else {
+			session.removeProperty(htmlID, "srcset")
 		}
-		notCompatibleType(Source, value)
 
 	case AltText:
-		if text, ok := value.(string); ok {
-			imageView.properties[AltText] = text
-			if imageView.created {
-				updateInnerHTML(imageView.htmlID(), imageView.session)
-			}
-			imageView.propertyChangedEvent(Source)
-			return true
-		}
-		notCompatibleType(tag, value)
+		updateInnerHTML(htmlID, session)
 
-	case LoadedEvent, ErrorEvent:
-		if listeners, ok := valueToNoParamListeners[ImageView](value); ok {
-			if listeners == nil {
-				delete(imageView.properties, tag)
-			} else {
-				imageView.properties[tag] = listeners
-			}
-			return true
-		}
+	case ImageVerticalAlign, ImageHorizontalAlign:
+		updateCSSStyle(htmlID, session)
 
 	default:
-		if imageView.viewData.set(tag, value) {
-			if imageView.created {
-				switch tag {
-				case ImageVerticalAlign, ImageHorizontalAlign:
-					updateCSSStyle(imageView.htmlID(), imageView.session)
-				}
-			}
-			return true
-		}
+		imageView.viewData.propertyChanged(tag)
 	}
-
-	return false
 }
 
-func (imageView *imageViewData) Get(tag string) any {
-	return imageView.viewData.get(imageView.normalizeTag(tag))
-}
-
-func (imageView *imageViewData) imageListeners(tag string) []func(ImageView) {
-	if value := imageView.getRaw(tag); value != nil {
-		if listeners, ok := value.([]func(ImageView)); ok {
-			return listeners
-		}
-	}
-	return []func(ImageView){}
-}
-
-func (imageView *imageViewData) srcSet(path string) string {
-	if value := imageView.getRaw(SrcSet); value != nil {
+func imageViewSrcSet(view View, path string) string {
+	if value := view.getRaw(SrcSet); value != nil {
 		if text, ok := value.(string); ok {
 			srcset := strings.Split(text, ",")
 			buffer := allocStringBuilder()
@@ -258,9 +216,9 @@ func (imageView *imageViewData) htmlTag() string {
 	return "img"
 }
 
-func (imageView *imageViewData) src(src string) (string, string) {
+func imageViewSrc(view View, src string) (string, string) {
 	if src != "" && src[0] == '@' {
-		if image, ok := imageView.Session().ImageConstant(src[1:]); ok {
+		if image, ok := view.Session().ImageConstant(src[1:]); ok {
 			src = image
 		} else {
 			src = ""
@@ -268,7 +226,7 @@ func (imageView *imageViewData) src(src string) (string, string) {
 	}
 
 	if src != "" {
-		return src, imageView.srcSet(src)
+		return src, imageViewSrcSet(view, src)
 	}
 	return "", ""
 }
@@ -278,7 +236,7 @@ func (imageView *imageViewData) htmlProperties(self View, buffer *strings.Builde
 	imageView.viewData.htmlProperties(self, buffer)
 
 	if imageResource, ok := imageProperty(imageView, Source, imageView.Session()); ok && imageResource != "" {
-		if src, srcset := imageView.src(imageResource); src != "" {
+		if src, srcset := imageViewSrc(imageView, imageResource); src != "" {
 			buffer.WriteString(` src="`)
 			buffer.WriteString(src)
 			buffer.WriteString(`"`)
@@ -298,7 +256,7 @@ func (imageView *imageViewData) htmlProperties(self View, buffer *strings.Builde
 
 	buffer.WriteString(` onload="imageLoaded(this, event)"`)
 
-	if len(imageView.imageListeners(ErrorEvent)) > 0 {
+	if len(getNoArgEventListeners[ImageView](imageView, nil, ErrorEvent)) > 0 {
 		buffer.WriteString(` onerror="imageError(this, event)"`)
 	}
 }
@@ -338,10 +296,10 @@ func (imageView *imageViewData) cssStyle(self View, builder cssBuilder) {
 	}
 }
 
-func (imageView *imageViewData) handleCommand(self View, command string, data DataObject) bool {
+func (imageView *imageViewData) handleCommand(self View, command PropertyName, data DataObject) bool {
 	switch command {
 	case "imageViewError":
-		for _, listener := range imageView.imageListeners(ErrorEvent) {
+		for _, listener := range getNoArgEventListeners[ImageView](imageView, nil, ErrorEvent) {
 			listener(imageView)
 		}
 
@@ -350,7 +308,7 @@ func (imageView *imageViewData) handleCommand(self View, command string, data Da
 		imageView.naturalHeight = dataFloatProperty(data, "natural-height")
 		imageView.currentSrc, _ = data.PropertyValue("current-src")
 
-		for _, listener := range imageView.imageListeners(LoadedEvent) {
+		for _, listener := range getNoArgEventListeners[ImageView](imageView, nil, LoadedEvent) {
 			listener(imageView)
 		}
 
@@ -371,11 +329,7 @@ func (imageView *imageViewData) CurrentSource() string {
 // GetImageViewSource returns the image URL of an ImageView subview.
 // If the second argument (subviewID) is not specified or it is "" then a left position of the first argument (view) is returned
 func GetImageViewSource(view View, subviewID ...string) string {
-	if len(subviewID) > 0 && subviewID[0] != "" {
-		view = ViewByID(view, subviewID[0])
-	}
-
-	if view != nil {
+	if view = getSubview(view, subviewID); view != nil {
 		if image, ok := imageProperty(view, Source, view.Session()); ok {
 			return image
 		}
@@ -387,11 +341,7 @@ func GetImageViewSource(view View, subviewID ...string) string {
 // GetImageViewAltText returns an alternative text description of an ImageView subview.
 // If the second argument (subviewID) is not specified or it is "" then a left position of the first argument (view) is returned
 func GetImageViewAltText(view View, subviewID ...string) string {
-	if len(subviewID) > 0 && subviewID[0] != "" {
-		view = ViewByID(view, subviewID[0])
-	}
-
-	if view != nil {
+	if view = getSubview(view, subviewID); view != nil {
 		if value := view.getRaw(AltText); value != nil {
 			if text, ok := value.(string); ok {
 				text, _ = view.Session().GetString(text)

keyEvents.go

@@ -2,27 +2,58 @@ package rui
 
 import "strings"
 
+// Constants which represent [View] specific keyboard events properties
 const (
-	// KeyDown is the constant for "key-down-event" property tag.
-	// The "key-down-event" event is fired when a key is pressed.
-	// The main listener format:
-	//   func(View, KeyEvent).
-	// The additional listener formats:
-	//   func(KeyEvent), func(View), and func().
-	KeyDownEvent = "key-down-event"
+	// KeyDownEvent is the constant for "key-down-event" property tag.
+	//
+	// Used by View.
+	// Is fired when a key is pressed.
+	//
+	// General listener format:
+	//
+	//  func(view rui.View, event rui.KeyEvent).
+	//
+	// where:
+	//   - view - Interface of a view which generated this event,
+	//   - event - Key event.
+	//
+	// Allowed listener formats:
+	//
+	//  func(view rui.View)
+	//  func(event rui.KeyEvent)
+	//  func()
+	KeyDownEvent PropertyName = "key-down-event"
 
-	// KeyPp is the constant for "key-up-event" property tag.
-	// The "key-up-event" event is fired when a key is released.
-	// The main listener format:
-	//   func(View, KeyEvent).
-	// The additional listener formats:
-	//   func(KeyEvent), func(View), and func().
-	KeyUpEvent = "key-up-event"
+	// KeyUpEvent is the constant for "key-up-event" property tag.
+	//
+	// Used by View.
+	// Is fired when a key is released.
+	//
+	// General listener format:
+	//
+	//  func(view rui.View, event rui.KeyEvent)
+	//
+	// where:
+	//   - view - Interface of a view which generated this event,
+	//   - event - Key event.
+	//
+	// Allowed listener formats:
+	//
+	//  func(view rui.View)
+	//  func(event rui.KeyEvent)
+	//  func()
+	KeyUpEvent PropertyName = "key-up-event"
 )
 
+// ControlKeyMask represent ORed state of keyboard's control keys like [AltKey], [CtrlKey], [ShiftKey] and [MetaKey]
 type ControlKeyMask int
+
+// KeyCode is a string representation the a physical key being pressed.
+// The value is not affected by the current keyboard layout or modifier state,
+// so a particular key will always have the same value.
 type KeyCode string
 
+// Constants for specific keyboard keys.
 const (
 	// AltKey is the mask of the "alt" key
 	AltKey ControlKeyMask = 1
@@ -33,114 +64,326 @@ const (
 	// MetaKey is the mask of the "meta" key
 	MetaKey ControlKeyMask = 8
 
-	KeyA              KeyCode = "KeyA"
-	KeyB              KeyCode = "KeyB"
-	KeyC              KeyCode = "KeyC"
-	KeyD              KeyCode = "KeyD"
-	KeyE              KeyCode = "KeyE"
-	KeyF              KeyCode = "KeyF"
-	KeyG              KeyCode = "KeyG"
-	KeyH              KeyCode = "KeyH"
-	KeyI              KeyCode = "KeyI"
-	KeyJ              KeyCode = "KeyJ"
-	KeyK              KeyCode = "KeyK"
-	KeyL              KeyCode = "KeyL"
-	KeyM              KeyCode = "KeyM"
-	KeyN              KeyCode = "KeyN"
-	KeyO              KeyCode = "KeyO"
-	KeyP              KeyCode = "KeyP"
-	KeyQ              KeyCode = "KeyQ"
-	KeyR              KeyCode = "KeyR"
-	KeyS              KeyCode = "KeyS"
-	KeyT              KeyCode = "KeyT"
-	KeyU              KeyCode = "KeyU"
-	KeyV              KeyCode = "KeyV"
-	KeyW              KeyCode = "KeyW"
-	KeyX              KeyCode = "KeyX"
-	KeyY              KeyCode = "KeyY"
-	KeyZ              KeyCode = "KeyZ"
-	Digit0Key         KeyCode = "Digit0"
-	Digit1Key         KeyCode = "Digit1"
-	Digit2Key         KeyCode = "Digit2"
-	Digit3Key         KeyCode = "Digit3"
-	Digit4Key         KeyCode = "Digit4"
-	Digit5Key         KeyCode = "Digit5"
-	Digit6Key         KeyCode = "Digit6"
-	Digit7Key         KeyCode = "Digit7"
-	Digit8Key         KeyCode = "Digit8"
-	Digit9Key         KeyCode = "Digit9"
-	SpaceKey          KeyCode = "Space"
-	MinusKey          KeyCode = "Minus"
-	EqualKey          KeyCode = "Equal"
-	IntlBackslashKey  KeyCode = "IntlBackslash"
-	BracketLeftKey    KeyCode = "BracketLeft"
-	BracketRightKey   KeyCode = "BracketRight"
-	SemicolonKey      KeyCode = "Semicolon"
-	CommaKey          KeyCode = "Comma"
-	PeriodKey         KeyCode = "Period"
-	QuoteKey          KeyCode = "Quote"
-	BackquoteKey      KeyCode = "Backquote"
-	SlashKey          KeyCode = "Slash"
-	EscapeKey         KeyCode = "Escape"
-	EnterKey          KeyCode = "Enter"
-	TabKey            KeyCode = "Tab"
-	CapsLockKey       KeyCode = "CapsLock"
-	DeleteKey         KeyCode = "Delete"
-	InsertKey         KeyCode = "Insert"
-	HelpKey           KeyCode = "Help"
-	BackspaceKey      KeyCode = "Backspace"
-	PrintScreenKey    KeyCode = "PrintScreen"
-	ScrollLockKey     KeyCode = "ScrollLock"
-	PauseKey          KeyCode = "Pause"
-	ContextMenuKey    KeyCode = "ContextMenu"
-	ArrowLeftKey      KeyCode = "ArrowLeft"
-	ArrowRightKey     KeyCode = "ArrowRight"
-	ArrowUpKey        KeyCode = "ArrowUp"
-	ArrowDownKey      KeyCode = "ArrowDown"
-	HomeKey           KeyCode = "Home"
-	EndKey            KeyCode = "End"
-	PageUpKey         KeyCode = "PageUp"
-	PageDownKey       KeyCode = "PageDown"
-	F1Key             KeyCode = "F1"
-	F2Key             KeyCode = "F2"
-	F3Key             KeyCode = "F3"
-	F4Key             KeyCode = "F4"
-	F5Key             KeyCode = "F5"
-	F6Key             KeyCode = "F6"
-	F7Key             KeyCode = "F7"
-	F8Key             KeyCode = "F8"
-	F9Key             KeyCode = "F9"
-	F10Key            KeyCode = "F10"
-	F11Key            KeyCode = "F11"
-	F12Key            KeyCode = "F12"
-	F13Key            KeyCode = "F13"
-	NumLockKey        KeyCode = "NumLock"
-	NumpadKey0        KeyCode = "Numpad0"
-	NumpadKey1        KeyCode = "Numpad1"
-	NumpadKey2        KeyCode = "Numpad2"
-	NumpadKey3        KeyCode = "Numpad3"
-	NumpadKey4        KeyCode = "Numpad4"
-	NumpadKey5        KeyCode = "Numpad5"
-	NumpadKey6        KeyCode = "Numpad6"
-	NumpadKey7        KeyCode = "Numpad7"
-	NumpadKey8        KeyCode = "Numpad8"
-	NumpadKey9        KeyCode = "Numpad9"
-	NumpadDecimalKey  KeyCode = "NumpadDecimal"
-	NumpadEnterKey    KeyCode = "NumpadEnter"
-	NumpadAddKey      KeyCode = "NumpadAdd"
+	// KeyA represent "A" key on the keyboard
+	KeyA KeyCode = "KeyA"
+
+	// KeyB represent "B" key on the keyboard
+	KeyB KeyCode = "KeyB"
+
+	// KeyC represent "C" key on the keyboard
+	KeyC KeyCode = "KeyC"
+
+	// KeyD represent "D" key on the keyboard
+	KeyD KeyCode = "KeyD"
+
+	// KeyE represent "E" key on the keyboard
+	KeyE KeyCode = "KeyE"
+
+	// KeyF represent "F" key on the keyboard
+	KeyF KeyCode = "KeyF"
+
+	// KeyG represent "G" key on the keyboard
+	KeyG KeyCode = "KeyG"
+
+	// KeyH represent "H" key on the keyboard
+	KeyH KeyCode = "KeyH"
+
+	// KeyI represent "I" key on the keyboard
+	KeyI KeyCode = "KeyI"
+
+	// KeyJ represent "J" key on the keyboard
+	KeyJ KeyCode = "KeyJ"
+
+	// KeyK represent "K" key on the keyboard
+	KeyK KeyCode = "KeyK"
+
+	// KeyL represent "L" key on the keyboard
+	KeyL KeyCode = "KeyL"
+
+	// KeyM represent "M" key on the keyboard
+	KeyM KeyCode = "KeyM"
+
+	// KeyN represent "N" key on the keyboard
+	KeyN KeyCode = "KeyN"
+
+	// KeyO represent "O" key on the keyboard
+	KeyO KeyCode = "KeyO"
+
+	// KeyP represent "P" key on the keyboard
+	KeyP KeyCode = "KeyP"
+
+	// KeyQ represent "Q" key on the keyboard
+	KeyQ KeyCode = "KeyQ"
+
+	// KeyR represent "R" key on the keyboard
+	KeyR KeyCode = "KeyR"
+
+	// KeyS represent "S" key on the keyboard
+	KeyS KeyCode = "KeyS"
+
+	// KeyT represent "T" key on the keyboard
+	KeyT KeyCode = "KeyT"
+
+	// KeyU represent "U" key on the keyboard
+	KeyU KeyCode = "KeyU"
+
+	// KeyV represent "V" key on the keyboard
+	KeyV KeyCode = "KeyV"
+
+	// KeyW represent "W" key on the keyboard
+	KeyW KeyCode = "KeyW"
+
+	// KeyX represent "X" key on the keyboard
+	KeyX KeyCode = "KeyX"
+
+	// KeyY represent "Y" key on the keyboard
+	KeyY KeyCode = "KeyY"
+
+	// KeyZ represent "Z" key on the keyboard
+	KeyZ KeyCode = "KeyZ"
+
+	// Digit0Key represent "Digit0" key on the keyboard
+	Digit0Key KeyCode = "Digit0"
+
+	// Digit1Key represent "Digit1" key on the keyboard
+	Digit1Key KeyCode = "Digit1"
+
+	// Digit2Key represent "Digit2" key on the keyboard
+	Digit2Key KeyCode = "Digit2"
+
+	// Digit3Key represent "Digit3" key on the keyboard
+	Digit3Key KeyCode = "Digit3"
+
+	// Digit4Key represent "Digit4" key on the keyboard
+	Digit4Key KeyCode = "Digit4"
+
+	// Digit5Key represent "Digit5" key on the keyboard
+	Digit5Key KeyCode = "Digit5"
+
+	// Digit6Key represent "Digit6" key on the keyboard
+	Digit6Key KeyCode = "Digit6"
+
+	// Digit7Key represent "Digit7" key on the keyboard
+	Digit7Key KeyCode = "Digit7"
+
+	// Digit8Key represent "Digit8" key on the keyboard
+	Digit8Key KeyCode = "Digit8"
+
+	// Digit9Key represent "Digit9" key on the keyboard
+	Digit9Key KeyCode = "Digit9"
+
+	// SpaceKey represent "Space" key on the keyboard
+	SpaceKey KeyCode = "Space"
+
+	// MinusKey represent "Minus" key on the keyboard
+	MinusKey KeyCode = "Minus"
+
+	// EqualKey represent "Equal" key on the keyboard
+	EqualKey KeyCode = "Equal"
+
+	// IntlBackslashKey represent "IntlBackslash" key on the keyboard
+	IntlBackslashKey KeyCode = "IntlBackslash"
+
+	// BracketLeftKey represent "BracketLeft" key on the keyboard
+	BracketLeftKey KeyCode = "BracketLeft"
+
+	// BracketRightKey represent "BracketRight" key on the keyboard
+	BracketRightKey KeyCode = "BracketRight"
+
+	// SemicolonKey represent "Semicolon" key on the keyboard
+	SemicolonKey KeyCode = "Semicolon"
+
+	// CommaKey represent "Comma" key on the keyboard
+	CommaKey KeyCode = "Comma"
+
+	// PeriodKey represent "Period" key on the keyboard
+	PeriodKey KeyCode = "Period"
+
+	// QuoteKey represent "Quote" key on the keyboard
+	QuoteKey KeyCode = "Quote"
+
+	// BackquoteKey represent "Backquote" key on the keyboard
+	BackquoteKey KeyCode = "Backquote"
+
+	// SlashKey represent "Slash" key on the keyboard
+	SlashKey KeyCode = "Slash"
+
+	// EscapeKey represent "Escape" key on the keyboard
+	EscapeKey KeyCode = "Escape"
+
+	// EnterKey represent "Enter" key on the keyboard
+	EnterKey KeyCode = "Enter"
+
+	// TabKey represent "Tab" key on the keyboard
+	TabKey KeyCode = "Tab"
+
+	// CapsLockKey represent "CapsLock" key on the keyboard
+	CapsLockKey KeyCode = "CapsLock"
+
+	// DeleteKey represent "Delete" key on the keyboard
+	DeleteKey KeyCode = "Delete"
+
+	// InsertKey represent "Insert" key on the keyboard
+	InsertKey KeyCode = "Insert"
+
+	// HelpKey represent "Help" key on the keyboard
+	HelpKey KeyCode = "Help"
+
+	// BackspaceKey represent "Backspace" key on the keyboard
+	BackspaceKey KeyCode = "Backspace"
+
+	// PrintScreenKey represent "PrintScreen" key on the keyboard
+	PrintScreenKey KeyCode = "PrintScreen"
+
+	// ScrollLockKey represent "ScrollLock" key on the keyboard
+	ScrollLockKey KeyCode = "ScrollLock"
+
+	// PauseKey represent "Pause" key on the keyboard
+	PauseKey KeyCode = "Pause"
+
+	// ContextMenuKey represent "ContextMenu" key on the keyboard
+	ContextMenuKey KeyCode = "ContextMenu"
+
+	// ArrowLeftKey represent "ArrowLeft" key on the keyboard
+	ArrowLeftKey KeyCode = "ArrowLeft"
+
+	// ArrowRightKey represent "ArrowRight" key on the keyboard
+	ArrowRightKey KeyCode = "ArrowRight"
+
+	// ArrowUpKey represent "ArrowUp" key on the keyboard
+	ArrowUpKey KeyCode = "ArrowUp"
+
+	// ArrowDownKey represent "ArrowDown" key on the keyboard
+	ArrowDownKey KeyCode = "ArrowDown"
+
+	// HomeKey represent "Home" key on the keyboard
+	HomeKey KeyCode = "Home"
+
+	// EndKey represent "End" key on the keyboard
+	EndKey KeyCode = "End"
+
+	// PageUpKey represent "PageUp" key on the keyboard
+	PageUpKey KeyCode = "PageUp"
+
+	// PageDownKey represent "PageDown" key on the keyboard
+	PageDownKey KeyCode = "PageDown"
+
+	// F1Key represent "F1" key on the keyboard
+	F1Key KeyCode = "F1"
+
+	// F2Key represent "F2" key on the keyboard
+	F2Key KeyCode = "F2"
+
+	// F3Key represent "F3" key on the keyboard
+	F3Key KeyCode = "F3"
+
+	// F4Key represent "F4" key on the keyboard
+	F4Key KeyCode = "F4"
+
+	// F5Key represent "F5" key on the keyboard
+	F5Key KeyCode = "F5"
+
+	// F6Key represent "F6" key on the keyboard
+	F6Key KeyCode = "F6"
+
+	// F7Key represent "F7" key on the keyboard
+	F7Key KeyCode = "F7"
+
+	// F8Key represent "F8" key on the keyboard
+	F8Key KeyCode = "F8"
+
+	// F9Key represent "F9" key on the keyboard
+	F9Key KeyCode = "F9"
+
+	// F10Key represent "F10" key on the keyboard
+	F10Key KeyCode = "F10"
+
+	// F11Key represent "F11" key on the keyboard
+	F11Key KeyCode = "F11"
+
+	// F12Key represent "F12" key on the keyboard
+	F12Key KeyCode = "F12"
+
+	// F13Key represent "F13" key on the keyboard
+	F13Key KeyCode = "F13"
+
+	// NumLockKey represent "NumLock" key on the keyboard
+	NumLockKey KeyCode = "NumLock"
+
+	// NumpadKey0 represent "Numpad0" key on the keyboard
+	NumpadKey0 KeyCode = "Numpad0"
+
+	// NumpadKey1 represent "Numpad1" key on the keyboard
+	NumpadKey1 KeyCode = "Numpad1"
+
+	// NumpadKey2 represent "Numpad2" key on the keyboard
+	NumpadKey2 KeyCode = "Numpad2"
+
+	// NumpadKey3 represent "Numpad3" key on the keyboard
+	NumpadKey3 KeyCode = "Numpad3"
+
+	// NumpadKey4 represent "Numpad4" key on the keyboard
+	NumpadKey4 KeyCode = "Numpad4"
+
+	// NumpadKey5 represent "Numpad5" key on the keyboard
+	NumpadKey5 KeyCode = "Numpad5"
+
+	// NumpadKey6 represent "Numpad6" key on the keyboard
+	NumpadKey6 KeyCode = "Numpad6"
+
+	// NumpadKey7 represent "Numpad7" key on the keyboard
+	NumpadKey7 KeyCode = "Numpad7"
+
+	// NumpadKey8 represent "Numpad8" key on the keyboard
+	NumpadKey8 KeyCode = "Numpad8"
+
+	// NumpadKey9 represent "Numpad9" key on the keyboard
+	NumpadKey9 KeyCode = "Numpad9"
+
+	// NumpadDecimalKey represent "NumpadDecimal" key on the keyboard
+	NumpadDecimalKey KeyCode = "NumpadDecimal"
+
+	// NumpadEnterKey represent "NumpadEnter" key on the keyboard
+	NumpadEnterKey KeyCode = "NumpadEnter"
+
+	// NumpadAddKey represent "NumpadAdd" key on the keyboard
+	NumpadAddKey KeyCode = "NumpadAdd"
+
+	// NumpadSubtractKey represent "NumpadSubtract" key on the keyboard
 	NumpadSubtractKey KeyCode = "NumpadSubtract"
+
+	// NumpadMultiplyKey represent "NumpadMultiply" key on the keyboard
 	NumpadMultiplyKey KeyCode = "NumpadMultiply"
-	NumpadDivideKey   KeyCode = "NumpadDivide"
-	ShiftLeftKey      KeyCode = "ShiftLeft"
-	ShiftRightKey     KeyCode = "ShiftRight"
-	ControlLeftKey    KeyCode = "ControlLeft"
-	ControlRightKey   KeyCode = "ControlRight"
-	AltLeftKey        KeyCode = "AltLeft"
-	AltRightKey       KeyCode = "AltRight"
-	MetaLeftKey       KeyCode = "MetaLeft"
-	MetaRightKey      KeyCode = "MetaRight"
+
+	// NumpadDivideKey represent "NumpadDivide" key on the keyboard
+	NumpadDivideKey KeyCode = "NumpadDivide"
+
+	// ShiftLeftKey represent "ShiftLeft" key on the keyboard
+	ShiftLeftKey KeyCode = "ShiftLeft"
+
+	// ShiftRightKey represent "ShiftRight" key on the keyboard
+	ShiftRightKey KeyCode = "ShiftRight"
+
+	// ControlLeftKey represent "ControlLeft" key on the keyboard
+	ControlLeftKey KeyCode = "ControlLeft"
+
+	// ControlRightKey represent "ControlRight" key on the keyboard
+	ControlRightKey KeyCode = "ControlRight"
+
+	// AltLeftKey represent "AltLeft" key on the keyboard
+	AltLeftKey KeyCode = "AltLeft"
+
+	// AltRightKey represent "AltRight" key on the keyboard
+	AltRightKey KeyCode = "AltRight"
+
+	// MetaLeftKey represent "MetaLeft" key on the keyboard
+	MetaLeftKey KeyCode = "MetaLeft"
+
+	// MetaRightKey represent "MetaRight" key on the keyboard
+	MetaRightKey KeyCode = "MetaRight"
 )
 
+// KeyEvent represent a keyboard event
 type KeyEvent struct {
 	// TimeStamp is the time at which the event was created (in milliseconds).
 	// This value is time since epoch—but in reality, browsers' definitions vary.
@@ -190,402 +433,24 @@ func (event *KeyEvent) init(data DataObject) {
 	event.MetaKey = getBool("metaKey")
 }
 
-func valueToEventListeners[V View, E any](value any) ([]func(V, E), bool) {
-	if value == nil {
-		return nil, true
-	}
-
-	switch value := value.(type) {
-	case func(V, E):
-		return []func(V, E){value}, true
-
-	case func(E):
-		fn := func(_ V, event E) {
-			value(event)
-		}
-		return []func(V, E){fn}, true
-
-	case func(V):
-		fn := func(view V, _ E) {
-			value(view)
-		}
-		return []func(V, E){fn}, true
-
-	case func():
-		fn := func(V, E) {
-			value()
-		}
-		return []func(V, E){fn}, true
-
-	case []func(V, E):
-		if len(value) == 0 {
-			return nil, true
-		}
-		for _, fn := range value {
-			if fn == nil {
-				return nil, false
-			}
-		}
-		return value, true
-
-	case []func(E):
-		count := len(value)
-		if count == 0 {
-			return nil, true
-		}
-		listeners := make([]func(V, E), count)
-		for i, v := range value {
-			if v == nil {
-				return nil, false
-			}
-			listeners[i] = func(_ V, event E) {
-				v(event)
-			}
-		}
-		return listeners, true
-
-	case []func(V):
-		count := len(value)
-		if count == 0 {
-			return nil, true
-		}
-		listeners := make([]func(V, E), count)
-		for i, v := range value {
-			if v == nil {
-				return nil, false
-			}
-			listeners[i] = func(view V, _ E) {
-				v(view)
-			}
-		}
-		return listeners, true
-
-	case []func():
-		count := len(value)
-		if count == 0 {
-			return nil, true
-		}
-		listeners := make([]func(V, E), count)
-		for i, v := range value {
-			if v == nil {
-				return nil, false
-			}
-			listeners[i] = func(V, E) {
-				v()
-			}
-		}
-		return listeners, true
-
-	case []any:
-		count := len(value)
-		if count == 0 {
-			return nil, true
-		}
-		listeners := make([]func(V, E), count)
-		for i, v := range value {
-			if v == nil {
-				return nil, false
-			}
-			switch v := v.(type) {
-			case func(V, E):
-				listeners[i] = v
-
-			case func(E):
-				listeners[i] = func(_ V, event E) {
-					v(event)
-				}
-
-			case func(V):
-				listeners[i] = func(view V, _ E) {
-					v(view)
-				}
-
-			case func():
-				listeners[i] = func(V, E) {
-					v()
-				}
-
-			default:
-				return nil, false
-			}
-		}
-		return listeners, true
-	}
-
-	return nil, false
-}
-
-func valueToEventWithOldListeners[V View, E any](value any) ([]func(V, E, E), bool) {
-	if value == nil {
-		return nil, true
-	}
-
-	switch value := value.(type) {
-	case func(V, E, E):
-		return []func(V, E, E){value}, true
-
-	case func(V, E):
-		fn := func(v V, val, _ E) {
-			value(v, val)
-		}
-		return []func(V, E, E){fn}, true
-
-	case func(E, E):
-		fn := func(_ V, val, old E) {
-			value(val, old)
-		}
-		return []func(V, E, E){fn}, true
-
-	case func(E):
-		fn := func(_ V, val, _ E) {
-			value(val)
-		}
-		return []func(V, E, E){fn}, true
-
-	case func(V):
-		fn := func(v V, _, _ E) {
-			value(v)
-		}
-		return []func(V, E, E){fn}, true
-
-	case func():
-		fn := func(V, E, E) {
-			value()
-		}
-		return []func(V, E, E){fn}, true
-
-	case []func(V, E, E):
-		if len(value) == 0 {
-			return nil, true
-		}
-		for _, fn := range value {
-			if fn == nil {
-				return nil, false
-			}
-		}
-		return value, true
-
-	case []func(V, E):
-		count := len(value)
-		if count == 0 {
-			return nil, true
-		}
-		listeners := make([]func(V, E, E), count)
-		for i, fn := range value {
-			if fn == nil {
-				return nil, false
-			}
-			listeners[i] = func(view V, val, _ E) {
-				fn(view, val)
-			}
-		}
-		return listeners, true
-
-	case []func(E):
-		count := len(value)
-		if count == 0 {
-			return nil, true
-		}
-		listeners := make([]func(V, E, E), count)
-		for i, fn := range value {
-			if fn == nil {
-				return nil, false
-			}
-			listeners[i] = func(_ V, val, _ E) {
-				fn(val)
-			}
-		}
-		return listeners, true
-
-	case []func(E, E):
-		count := len(value)
-		if count == 0 {
-			return nil, true
-		}
-		listeners := make([]func(V, E, E), count)
-		for i, fn := range value {
-			if fn == nil {
-				return nil, false
-			}
-			listeners[i] = func(_ V, val, old E) {
-				fn(val, old)
-			}
-		}
-		return listeners, true
-
-	case []func(V):
-		count := len(value)
-		if count == 0 {
-			return nil, true
-		}
-		listeners := make([]func(V, E, E), count)
-		for i, fn := range value {
-			if fn == nil {
-				return nil, false
-			}
-			listeners[i] = func(view V, _, _ E) {
-				fn(view)
-			}
-		}
-		return listeners, true
-
-	case []func():
-		count := len(value)
-		if count == 0 {
-			return nil, true
-		}
-		listeners := make([]func(V, E, E), count)
-		for i, fn := range value {
-			if fn == nil {
-				return nil, false
-			}
-			listeners[i] = func(V, E, E) {
-				fn()
-			}
-		}
-		return listeners, true
-
-	case []any:
-		count := len(value)
-		if count == 0 {
-			return nil, true
-		}
-		listeners := make([]func(V, E, E), count)
-		for i, v := range value {
-			if v == nil {
-				return nil, false
-			}
-			switch fn := v.(type) {
-			case func(V, E, E):
-				listeners[i] = fn
-
-			case func(V, E):
-				listeners[i] = func(view V, val, _ E) {
-					fn(view, val)
-				}
-
-			case func(E, E):
-				listeners[i] = func(_ V, val, old E) {
-					fn(val, old)
-				}
-
-			case func(E):
-				listeners[i] = func(_ V, val, _ E) {
-					fn(val)
-				}
-
-			case func(V):
-				listeners[i] = func(view V, _, _ E) {
-					fn(view)
-				}
-
-			case func():
-				listeners[i] = func(V, E, E) {
-					fn()
-				}
-
-			default:
-				return nil, false
-			}
-		}
-		return listeners, true
-	}
-
-	return nil, false
-}
-
-func (view *viewData) setKeyListener(tag string, value any) bool {
-	listeners, ok := valueToEventListeners[View, KeyEvent](value)
-	if !ok {
-		notCompatibleType(tag, value)
-		return false
-	}
-
-	if listeners == nil {
-		view.removeKeyListener(tag)
-	} else {
-		switch tag {
-		case KeyDownEvent:
-			view.properties[tag] = listeners
-			if view.created {
-				view.session.updateProperty(view.htmlID(), "onkeydown", "keyDownEvent(this, event)")
-			}
-
-		case KeyUpEvent:
-			view.properties[tag] = listeners
-			if view.created {
-				view.session.updateProperty(view.htmlID(), "onkeyup", "keyUpEvent(this, event)")
-			}
-
-		default:
-			return false
-		}
-	}
-
-	return true
-}
-
-func (view *viewData) removeKeyListener(tag string) {
-	delete(view.properties, tag)
-	if view.created {
-		switch tag {
-		case KeyDownEvent:
-			if !view.Focusable() {
-				view.session.removeProperty(view.htmlID(), "onkeydown")
-			}
-
-		case KeyUpEvent:
-			view.session.removeProperty(view.htmlID(), "onkeyup")
-		}
-	}
-}
-
-func getEventWithOldListeners[V View, E any](view View, subviewID []string, tag string) []func(V, E, E) {
-	if len(subviewID) > 0 && subviewID[0] != "" {
-		view = ViewByID(view, subviewID[0])
-	}
-	if view != nil {
-		if value := view.Get(tag); value != nil {
-			if result, ok := value.([]func(V, E, E)); ok {
-				return result
-			}
-		}
-	}
-	return []func(V, E, E){}
-}
-
-func getEventListeners[V View, E any](view View, subviewID []string, tag string) []func(V, E) {
-	if len(subviewID) > 0 && subviewID[0] != "" {
-		view = ViewByID(view, subviewID[0])
-	}
-	if view != nil {
-		if value := view.Get(tag); value != nil {
-			if result, ok := value.([]func(V, E)); ok {
-				return result
-			}
-		}
-	}
-	return []func(V, E){}
-}
-
 func keyEventsHtml(view View, buffer *strings.Builder) {
-	if len(getEventListeners[View, KeyEvent](view, nil, KeyDownEvent)) > 0 {
+	if len(getOneArgEventListeners[View, KeyEvent](view, nil, KeyDownEvent)) > 0 {
 		buffer.WriteString(`onkeydown="keyDownEvent(this, event)" `)
 	} else if view.Focusable() {
-		if len(getEventListeners[View, MouseEvent](view, nil, ClickEvent)) > 0 {
+		if len(getOneArgEventListeners[View, MouseEvent](view, nil, ClickEvent)) > 0 {
 			buffer.WriteString(`onkeydown="keyDownEvent(this, event)" `)
 		}
 	}
 
-	if listeners := getEventListeners[View, KeyEvent](view, nil, KeyUpEvent); len(listeners) > 0 {
+	if listeners := getOneArgEventListeners[View, KeyEvent](view, nil, KeyUpEvent); len(listeners) > 0 {
 		buffer.WriteString(`onkeyup="keyUpEvent(this, event)" `)
 	}
 }
 
-func handleKeyEvents(view View, tag string, data DataObject) {
+func handleKeyEvents(view View, tag PropertyName, data DataObject) {
 	var event KeyEvent
 	event.init(data)
-	listeners := getEventListeners[View, KeyEvent](view, nil, tag)
+	listeners := getOneArgEventListeners[View, KeyEvent](view, nil, tag)
 
 	if len(listeners) > 0 {
 		for _, listener := range listeners {
@@ -595,7 +460,7 @@ func handleKeyEvents(view View, tag string, data DataObject) {
 	}
 
 	if tag == KeyDownEvent && view.Focusable() && (event.Key == " " || event.Key == "Enter") && !IsDisabled(view) {
-		if listeners := getEventListeners[View, MouseEvent](view, nil, ClickEvent); len(listeners) > 0 {
+		if listeners := getOneArgEventListeners[View, MouseEvent](view, nil, ClickEvent); len(listeners) > 0 {
 			clickEvent := MouseEvent{
 				TimeStamp: event.TimeStamp,
 				Button:    PrimaryMouseButton,
@@ -621,11 +486,11 @@ func handleKeyEvents(view View, tag string, data DataObject) {
 // GetKeyDownListeners returns the "key-down-event" listener list. If there are no listeners then the empty list is returned.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetKeyDownListeners(view View, subviewID ...string) []func(View, KeyEvent) {
-	return getEventListeners[View, KeyEvent](view, subviewID, KeyDownEvent)
+	return getOneArgEventListeners[View, KeyEvent](view, subviewID, KeyDownEvent)
 }
 
 // GetKeyUpListeners returns the "key-up-event" listener list. If there are no listeners then the empty list is returned.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetKeyUpListeners(view View, subviewID ...string) []func(View, KeyEvent) {
-	return getEventListeners[View, KeyEvent](view, subviewID, KeyUpEvent)
+	return getOneArgEventListeners[View, KeyEvent](view, subviewID, KeyUpEvent)
 }

listLayout.go

@@ -4,6 +4,7 @@ import (
 	"strings"
 )
 
+// Constants which represent values of the "orientation" property of the [ListLayout]
 const (
 	// TopDownOrientation - subviews are arranged from top to bottom. Synonym of VerticalOrientation
 	TopDownOrientation = 0
@@ -16,7 +17,10 @@ const (
 
 	// EndToStartOrientation - subviews are arranged from right to left
 	EndToStartOrientation = 3
+)
 
+// Constants which represent values of the "list-wrap" property of the [ListLayout]
+const (
 	// ListWrapOff - subviews are scrolled and "true" if a new row/column starts
 	ListWrapOff = 0
 
@@ -27,7 +31,7 @@ const (
 	ListWrapReverse = 2
 )
 
-// ListLayout - list-container of View
+// ListLayout represents a ListLayout view
 type ListLayout interface {
 	ViewsContainer
 	// UpdateContent updates child Views if the "content" property value is set to ListAdapter,
@@ -49,7 +53,8 @@ func NewListLayout(session Session, params Params) ListLayout {
 }
 
 func newListLayout(session Session) View {
-	return NewListLayout(session, nil)
+	//return NewListLayout(session, nil)
+	return new(listLayoutData)
 }
 
 // Init initialize fields of ViewsAlignContainer by default values
@@ -57,14 +62,16 @@ func (listLayout *listLayoutData) init(session Session) {
 	listLayout.viewsContainerData.init(session)
 	listLayout.tag = "ListLayout"
 	listLayout.systemClass = "ruiListLayout"
+	listLayout.normalize = normalizeListLayoutTag
+	listLayout.get = listLayout.getFunc
+	listLayout.set = listLayout.setFunc
+	listLayout.remove = listLayout.removeFunc
+	listLayout.changed = listLayout.propertyChanged
+
 }
 
-func (listLayout *listLayoutData) String() string {
-	return getViewString(listLayout, nil)
-}
-
-func (listLayout *listLayoutData) normalizeTag(tag string) string {
-	tag = strings.ToLower(tag)
+func normalizeListLayoutTag(tag PropertyName) PropertyName {
+	tag = defaultNormalize(tag)
 	switch tag {
 	case "wrap":
 		tag = ListWrap
@@ -78,91 +85,90 @@ func (listLayout *listLayoutData) normalizeTag(tag string) string {
 	return tag
 }
 
-func (listLayout *listLayoutData) Get(tag string) any {
-	return listLayout.get(listLayout.normalizeTag(tag))
-}
-
-func (listLayout *listLayoutData) get(tag string) any {
-	if tag == Gap {
+func (listLayout *listLayoutData) getFunc(tag PropertyName) any {
+	switch tag {
+	case Gap:
 		if rowGap := GetListRowGap(listLayout); rowGap.Equal(GetListColumnGap(listLayout)) {
 			return rowGap
 		}
 		return AutoSize()
-	}
-
-	return listLayout.viewsContainerData.get(tag)
-}
-
-func (listLayout *listLayoutData) Remove(tag string) {
-	listLayout.remove(listLayout.normalizeTag(tag))
-}
-
-func (listLayout *listLayoutData) remove(tag string) {
-	switch tag {
-	case Gap:
-		listLayout.remove(ListRowGap)
-		listLayout.remove(ListColumnGap)
-		return
 
 	case Content:
-		listLayout.adapter = nil
-	}
-
-	listLayout.viewsContainerData.remove(tag)
-	if listLayout.created {
-		switch tag {
-		case Orientation, ListWrap, HorizontalAlign, VerticalAlign:
-			updateCSSStyle(listLayout.htmlID(), listLayout.session)
+		if listLayout.adapter != nil {
+			return listLayout.adapter
 		}
 	}
+
+	return listLayout.viewsContainerData.getFunc(tag)
 }
 
-func (listLayout *listLayoutData) Set(tag string, value any) bool {
-	return listLayout.set(listLayout.normalizeTag(tag), value)
-}
-
-func (listLayout *listLayoutData) set(tag string, value any) bool {
-	if value == nil {
-		listLayout.remove(tag)
-		return true
-	}
-
+func (listLayout *listLayoutData) removeFunc(tag PropertyName) []PropertyName {
 	switch tag {
 	case Gap:
-		return listLayout.set(ListRowGap, value) && listLayout.set(ListColumnGap, value)
+		result := []PropertyName{}
+		for _, tag := range []PropertyName{ListRowGap, ListColumnGap} {
+			if listLayout.getRaw(tag) != nil {
+				listLayout.setRaw(tag, nil)
+				result = append(result, tag)
+			}
+		}
+		return result
+
+	case Content:
+		listLayout.viewsContainerData.removeFunc(Content)
+		listLayout.adapter = nil
+		return []PropertyName{Content}
+	}
+
+	return listLayout.viewsContainerData.removeFunc(tag)
+}
+
+func (listLayout *listLayoutData) setFunc(tag PropertyName, value any) []PropertyName {
+	switch tag {
+	case Gap:
+		result := listLayout.setFunc(ListRowGap, value)
+		if result != nil {
+			if gap := listLayout.getRaw(ListRowGap); gap != nil {
+				listLayout.setRaw(ListColumnGap, gap)
+				result = append(result, ListColumnGap)
+			}
+		}
+		return result
 
 	case Content:
 		if adapter, ok := value.(ListAdapter); ok {
 			listLayout.adapter = adapter
-			listLayout.UpdateContent()
-			// TODO
-			return true
+			listLayout.createContent()
+		} else if listLayout.setContent(value) {
+			listLayout.adapter = nil
+		} else {
+			return nil
 		}
-		listLayout.adapter = nil
+		return []PropertyName{Content}
 	}
+	return listLayout.viewsContainerData.setFunc(tag, value)
+}
 
-	if listLayout.viewsContainerData.set(tag, value) {
-		if listLayout.created {
-			switch tag {
-			case Orientation, ListWrap, HorizontalAlign, VerticalAlign:
-				updateCSSStyle(listLayout.htmlID(), listLayout.session)
-			}
-		}
-		return true
+func (listLayout *listLayoutData) propertyChanged(tag PropertyName) {
+	switch tag {
+	case Orientation, ListWrap, HorizontalAlign, VerticalAlign:
+		updateCSSStyle(listLayout.htmlID(), listLayout.Session())
+
+	default:
+		listLayout.viewsContainerData.propertyChanged(tag)
 	}
-	return false
 }
 
 func (listLayout *listLayoutData) htmlSubviews(self View, buffer *strings.Builder) {
 	if listLayout.views != nil {
 		for _, view := range listLayout.views {
 			view.addToCSSStyle(map[string]string{`flex`: `0 0 auto`})
-			viewHTML(view, buffer)
+			viewHTML(view, buffer, "")
 		}
 	}
 }
 
-func (listLayout *listLayoutData) UpdateContent() {
+func (listLayout *listLayoutData) createContent() bool {
 	if adapter := listLayout.adapter; adapter != nil {
 		listLayout.views = []View{}
 
@@ -181,11 +187,20 @@ func (listLayout *listLayoutData) UpdateContent() {
 			}
 		}
 
+		return true
+	}
+	return false
+}
+
+func (listLayout *listLayoutData) UpdateContent() {
+	if listLayout.createContent() {
 		if listLayout.created {
-			updateInnerHTML(htmlID, session)
+			updateInnerHTML(listLayout.htmlID(), listLayout.session)
 		}
 
-		listLayout.propertyChangedEvent(Content)
+		if listener, ok := listLayout.changeListener[Content]; ok {
+			listener(listLayout, Content)
+		}
 	}
 }
 
@@ -207,11 +222,7 @@ func GetListHorizontalAlign(view View, subviewID ...string) int {
 // TopDownOrientation (0), StartToEndOrientation (1), BottomUpOrientation (2), or EndToStartOrientation (3)
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetListOrientation(view View, subviewID ...string) int {
-	if len(subviewID) > 0 && subviewID[0] != "" {
-		view = ViewByID(view, subviewID[0])
-	}
-
-	if view != nil {
+	if view = getSubview(view, subviewID); view != nil {
 		if orientation, ok := valueToOrientation(view.Get(Orientation), view.Session()); ok {
 			return orientation
 		}
@@ -249,11 +260,7 @@ func GetListColumnGap(view View, subviewID ...string) SizeUnit {
 // otherwise does nothing.
 // If the second argument (subviewID) is not specified or it is "" then the first argument (view) updates.
 func UpdateContent(view View, subviewID ...string) {
-	if len(subviewID) > 0 && subviewID[0] != "" {
-		view = ViewByID(view, subviewID[0])
-	}
-
-	if view != nil {
+	if view = getSubview(view, subviewID); view != nil {
 		switch view := view.(type) {
 		case GridLayout:
 			view.UpdateGridContent()
@@ -263,6 +270,9 @@ func UpdateContent(view View, subviewID ...string) {
 
 		case ListView:
 			view.ReloadListViewData()
+
+		case TableView:
+			view.ReloadTableData()
 		}
 	}
 }

mouseEvents.go

@@ -5,80 +5,171 @@ import (
 	"strings"
 )
 
+// Constants related to [View] mouse events properties
 const (
 	// ClickEvent is the constant for "click-event" property tag.
-	// The "click-event" event occurs when the user clicks on the View.
-	// The main listener format:
-	//   func(View, MouseEvent).
-	// The additional listener formats:
-	//   func(MouseEvent), func(View), and func().
-	ClickEvent = "click-event"
+	//
+	// Used by View.
+	// Occur when the user clicks on the view.
+	//
+	// General listener format:
+	//
+	//  func(view rui.View, event rui.MouseEvent)
+	//
+	// where:
+	//   - view - Interface of a view which generated this event,
+	//   - event - Mouse event.
+	//
+	// Allowed listener formats:
+	//
+	//  func(view rui.View)
+	//  func(event rui.MouseEvent)
+	//  func()
+	ClickEvent PropertyName = "click-event"
 
 	// DoubleClickEvent is the constant for "double-click-event" property tag.
-	// The "double-click-event" event occurs when the user double clicks on the View.
-	// The main listener format:
-	//   func(View, MouseEvent).
-	// The additional listener formats:
-	//   func(MouseEvent), func(View), and func().
-	DoubleClickEvent = "double-click-event"
+	//
+	// Used by View.
+	// Occur when the user double clicks on the view.
+	//
+	// General listener format:
+	//
+	//  func(view rui.View, event rui.MouseEvent)
+	//
+	// where:
+	//   - view - Interface of a view which generated this event,
+	//   - event - Mouse event.
+	//
+	// Allowed listener formats:
+	//
+	//  func(view rui.View)
+	//  func(event rui.MouseEvent)
+	//  func()
+	DoubleClickEvent PropertyName = "double-click-event"
 
 	// MouseDown is the constant for "mouse-down" property tag.
-	// The "mouse-down" event is fired at a View when a pointing device button is pressed
-	// while the pointer is inside the view.
-	// The main listener format:
-	//   func(View, MouseEvent).
-	// The additional listener formats:
-	//   func(MouseEvent), func(View), and func().
-	MouseDown = "mouse-down"
+	//
+	// Used by View.
+	// Is fired at a View when a pointing device button is pressed while the pointer is inside the view.
+	//
+	// General listener format:
+	//
+	//  func(view rui.View, event rui.MouseEvent)
+	//
+	// where:
+	//   - view - Interface of a view which generated this event,
+	//   - event - Mouse event.
+	//
+	// Allowed listener formats:
+	//
+	//  func(view rui.View)
+	//  func(event rui.MouseEvent)
+	//  func()
+	MouseDown PropertyName = "mouse-down"
 
 	// MouseUp is the constant for "mouse-up" property tag.
-	// The "mouse-up" event is fired at a View when a button on a pointing device (such as a mouse
-	// or trackpad) is released while the pointer is located inside it.
-	// "mouse-up" events are the counterpoint to "mouse-down" events.
-	// The main listener format:
-	//   func(View, MouseEvent).
-	// The additional listener formats:
-	//   func(MouseEvent), func(View), and func().
-	MouseUp = "mouse-up"
+	//
+	// Used by View.
+	// Is fired at a View when a button on a pointing device (such as a mouse or trackpad) is released while the pointer is
+	// located inside it. "mouse-up" events are the counterpoint to "mouse-down" events.
+	//
+	// General listener format:
+	//
+	//  func(view rui.View, event rui.MouseEvent)
+	//
+	// where:
+	//   - view - Interface of a view which generated this event,
+	//   - event - Mouse event.
+	//
+	// Allowed listener formats:
+	//
+	//  func(view rui.View)
+	//  func(event rui.MouseEvent)
+	//  func()
+	MouseUp PropertyName = "mouse-up"
 
 	// MouseMove is the constant for "mouse-move" property tag.
-	// The "mouse-move" event is fired at a view when a pointing device (usually a mouse) is moved
-	// while the cursor's hotspot is inside it.
-	// The main listener format:
-	//   func(View, MouseEvent).
-	// The additional listener formats:
-	//   func(MouseEvent), func(View), and func().
-	MouseMove = "mouse-move"
+	//
+	// Used by View.
+	// Is fired at a view when a pointing device(usually a mouse) is moved while the cursor's hotspot is inside it.
+	//
+	// General listener format:
+	//
+	//  func(view rui.View, event rui.MouseEvent)
+	//
+	// where:
+	//   - view - Interface of a view which generated this event,
+	//   - event - Mouse event.
+	//
+	// Allowed listener formats:
+	//
+	//  func(view rui.View)
+	//  func(event rui.MouseEvent)
+	//  func()
+	MouseMove PropertyName = "mouse-move"
 
 	// MouseOut is the constant for "mouse-out" property tag.
-	// The "mouse-out" event is fired at a View when a pointing device (usually a mouse) is used to move
-	// the cursor so that it is no longer contained within the view or one of its children.
-	// "mouse-out" is also delivered to a view if the cursor enters a child view,
-	// because the child view obscures the visible area of the view.
-	// The main listener format:
-	//   func(View, MouseEvent).
-	// The additional listener formats:
-	//   func(MouseEvent), func(View), and func().
-	// The additional listener formats:
-	//   func(MouseEvent), func(View), and func().
-	MouseOut = "mouse-out"
+	//
+	// Used by View.
+	// Is fired at a View when a pointing device (usually a mouse) is used to move the cursor so that it is no longer
+	// contained within the view or one of its children. "mouse-out" is also delivered to a view if the cursor enters a child
+	// view, because the child view obscures the visible area of the view.
+	//
+	// General listener format:
+	//
+	//  func(view rui.View, event rui.MouseEvent)
+	//
+	// where:
+	//   - view - Interface of a view which generated this event,
+	//   - event - Mouse event.
+	//
+	// Allowed listener formats:
+	//
+	//  func(view rui.View)
+	//  func(event rui.MouseEvent)
+	//  func()
+	MouseOut PropertyName = "mouse-out"
 
 	// MouseOver is the constant for "mouse-over" property tag.
-	// The "mouse-over" event is fired at a View when a pointing device (such as a mouse or trackpad)
-	// is used to move the cursor onto the view or one of its child views.
-	// The main listener formats:
-	//   func(View, MouseEvent).
-	// The additional listener formats:
-	//   func(MouseEvent), func(View), and func().
-	MouseOver = "mouse-over"
+	//
+	// Used by View.
+	// Is fired at a View when a pointing device (such as a mouse or trackpad) is used to move the cursor onto the view or one
+	// of its child views.
+	//
+	// General listener format:
+	//
+	//  func(view rui.View, event rui.MouseEvent)
+	//
+	// where:
+	//   - view - Interface of a view which generated this event,
+	//   - event - Mouse event.
+	//
+	// Allowed listener formats:
+	//
+	//  func(view rui.View)
+	//  func(event rui.MouseEvent)
+	//  func()
+	MouseOver PropertyName = "mouse-over"
 
 	// ContextMenuEvent is the constant for "context-menu-event" property tag.
-	// The "context-menu-event" event occurs when the user calls the context menu by the right mouse clicking.
-	// The main listener format:
-	//   func(View, MouseEvent).
-	// The additional listener formats:
-	//   func(MouseEvent), func(View), and func().
-	ContextMenuEvent = "context-menu-event"
+	//
+	// Used by View.
+	// Occur when the user calls the context menu by the right mouse clicking.
+	//
+	// General listener format:
+	//
+	//  func(view rui.View, event rui.MouseEvent)
+	//
+	// where:
+	//   - view - Interface of a view which generated this event,
+	//   - event - Mouse event.
+	//
+	// Allowed listener formats:
+	//
+	//  func(view rui.View)
+	//  func(event rui.MouseEvent)
+	//  func()
+	ContextMenuEvent PropertyName = "context-menu-event"
 
 	// PrimaryMouseButton is a number of the main pressed button, usually the left button or the un-initialized state
 	PrimaryMouseButton = 0
@@ -112,6 +203,7 @@ const (
 	MouseMask5 = 16
 )
 
+// MouseEvent represent a mouse event
 type MouseEvent struct {
 	// TimeStamp is the time at which the event was created (in milliseconds).
 	// This value is time since epoch—but in reality, browsers' definitions vary.
@@ -152,64 +244,6 @@ type MouseEvent struct {
 	MetaKey bool
 }
 
-var mouseEvents = map[string]struct{ jsEvent, jsFunc string }{
-	ClickEvent:       {jsEvent: "onclick", jsFunc: "clickEvent"},
-	DoubleClickEvent: {jsEvent: "ondblclick", jsFunc: "doubleClickEvent"},
-	MouseDown:        {jsEvent: "onmousedown", jsFunc: "mouseDownEvent"},
-	MouseUp:          {jsEvent: "onmouseup", jsFunc: "mouseUpEvent"},
-	MouseMove:        {jsEvent: "onmousemove", jsFunc: "mouseMoveEvent"},
-	MouseOut:         {jsEvent: "onmouseout", jsFunc: "mouseOutEvent"},
-	MouseOver:        {jsEvent: "onmouseover", jsFunc: "mouseOverEvent"},
-	ContextMenuEvent: {jsEvent: "oncontextmenu", jsFunc: "contextMenuEvent"},
-}
-
-func (view *viewData) setMouseListener(tag string, value any) bool {
-	listeners, ok := valueToEventListeners[View, MouseEvent](value)
-	if !ok {
-		notCompatibleType(tag, value)
-		return false
-	}
-
-	if listeners == nil {
-		view.removeMouseListener(tag)
-	} else if js, ok := mouseEvents[tag]; ok {
-		view.properties[tag] = listeners
-		if view.created {
-			view.session.updateProperty(view.htmlID(), js.jsEvent, js.jsFunc+"(this, event)")
-		}
-	} else {
-		return false
-	}
-	return true
-}
-
-func (view *viewData) removeMouseListener(tag string) {
-	delete(view.properties, tag)
-	if view.created {
-		if js, ok := mouseEvents[tag]; ok {
-			view.session.removeProperty(view.htmlID(), js.jsEvent)
-		}
-	}
-}
-
-func mouseEventsHtml(view View, buffer *strings.Builder, hasTooltip bool) {
-	for tag, js := range mouseEvents {
-		if value := view.getRaw(tag); value != nil {
-			if listeners, ok := value.([]func(View, MouseEvent)); ok && len(listeners) > 0 {
-				buffer.WriteString(js.jsEvent)
-				buffer.WriteString(`="`)
-				buffer.WriteString(js.jsFunc)
-				buffer.WriteString(`(this, event)" `)
-			}
-		}
-	}
-
-	if hasTooltip {
-		buffer.WriteString(`onmouseenter="mouseEnterEvent(this, event)" `)
-		buffer.WriteString(`onmouseleave="mouseLeaveEvent(this, event)" `)
-	}
-}
-
 func getTimeStamp(data DataObject) uint64 {
 	if value, ok := data.PropertyValue("timeStamp"); ok {
 		if index := strings.Index(value, "."); index > 0 {
@@ -239,8 +273,8 @@ func (event *MouseEvent) init(data DataObject) {
 	event.MetaKey = dataBoolProperty(data, "metaKey")
 }
 
-func handleMouseEvents(view View, tag string, data DataObject) {
-	listeners := getEventListeners[View, MouseEvent](view, nil, tag)
+func handleMouseEvents(view View, tag PropertyName, data DataObject) {
+	listeners := getOneArgEventListeners[View, MouseEvent](view, nil, tag)
 	if len(listeners) > 0 {
 		var event MouseEvent
 		event.init(data)
@@ -254,48 +288,48 @@ func handleMouseEvents(view View, tag string, data DataObject) {
 // GetClickListeners returns the "click-event" listener list. If there are no listeners then the empty list is returned.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetClickListeners(view View, subviewID ...string) []func(View, MouseEvent) {
-	return getEventListeners[View, MouseEvent](view, subviewID, ClickEvent)
+	return getOneArgEventListeners[View, MouseEvent](view, subviewID, ClickEvent)
 }
 
 // GetDoubleClickListeners returns the "double-click-event" listener list. If there are no listeners then the empty list is returned.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetDoubleClickListeners(view View, subviewID ...string) []func(View, MouseEvent) {
-	return getEventListeners[View, MouseEvent](view, subviewID, DoubleClickEvent)
+	return getOneArgEventListeners[View, MouseEvent](view, subviewID, DoubleClickEvent)
 }
 
 // GetContextMenuListeners returns the "context-menu" listener list.
 // If there are no listeners then the empty list is returned.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetContextMenuListeners(view View, subviewID ...string) []func(View, MouseEvent) {
-	return getEventListeners[View, MouseEvent](view, subviewID, ContextMenuEvent)
+	return getOneArgEventListeners[View, MouseEvent](view, subviewID, ContextMenuEvent)
 }
 
 // GetMouseDownListeners returns the "mouse-down" listener list. If there are no listeners then the empty list is returned.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetMouseDownListeners(view View, subviewID ...string) []func(View, MouseEvent) {
-	return getEventListeners[View, MouseEvent](view, subviewID, MouseDown)
+	return getOneArgEventListeners[View, MouseEvent](view, subviewID, MouseDown)
 }
 
 // GetMouseUpListeners returns the "mouse-up" listener list. If there are no listeners then the empty list is returned.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetMouseUpListeners(view View, subviewID ...string) []func(View, MouseEvent) {
-	return getEventListeners[View, MouseEvent](view, subviewID, MouseUp)
+	return getOneArgEventListeners[View, MouseEvent](view, subviewID, MouseUp)
 }
 
 // GetMouseMoveListeners returns the "mouse-move" listener list. If there are no listeners then the empty list is returned.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetMouseMoveListeners(view View, subviewID ...string) []func(View, MouseEvent) {
-	return getEventListeners[View, MouseEvent](view, subviewID, MouseMove)
+	return getOneArgEventListeners[View, MouseEvent](view, subviewID, MouseMove)
 }
 
 // GetMouseOverListeners returns the "mouse-over" listener list. If there are no listeners then the empty list is returned.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetMouseOverListeners(view View, subviewID ...string) []func(View, MouseEvent) {
-	return getEventListeners[View, MouseEvent](view, subviewID, MouseOver)
+	return getOneArgEventListeners[View, MouseEvent](view, subviewID, MouseOver)
 }
 
 // GetMouseOutListeners returns the "mouse-out" listener list. If there are no listeners then the empty list is returned.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetMouseOutListeners(view View, subviewID ...string) []func(View, MouseEvent) {
-	return getEventListeners[View, MouseEvent](view, subviewID, MouseOut)
+	return getOneArgEventListeners[View, MouseEvent](view, subviewID, MouseOut)
 }

numberPicker.go

@@ -1,39 +1,100 @@
 package rui
 
 import (
+	"fmt"
 	"math"
 	"strconv"
 	"strings"
 )
 
+// Constants related to [NumberPicker] specific properties and events
 const (
-	// NumberChangedEvent is the constant for the "" property tag.
-	// The "number-changed" property sets listener(s) that track the change in the entered value.
-	NumberChangedEvent = "number-changed"
+	// NumberChangedEvent is the constant for "number-changed" property tag.
+	//
+	// Used by NumberPicker.
+	// Set listener(s) that track the change in the entered value.
+	//
+	// General listener format:
+	//
+	//  func(picker rui.NumberPicker, newValue float64, oldValue float64)
+	//
+	// where:
+	//   - picker - Interface of a number picker which generated this event,
+	//   - newValue - New value,
+	//   - oldValue - Old Value.
+	//
+	// Allowed listener formats:
+	//
+	//  func(picker rui.NumberPicker, newValue float64)
+	//  func(newValue float64, oldValue float64)
+	//  func(newValue float64)
+	//  func()
+	NumberChangedEvent PropertyName = "number-changed"
 
-	// NumberPickerType is the constant for the "number-picker-type" property tag.
-	// The "number-picker-type" int property sets the mode of NumberPicker. It can take the following values:
-	// * NumberEditor (0) - NumberPicker is presented by editor. Default value;
-	// * NumberSlider (1) - NumberPicker is presented by slider.                     |
-	NumberPickerType = "number-picker-type"
+	// NumberPickerType is the constant for "number-picker-type" property tag.
+	//
+	// Used by NumberPicker.
+	// Sets the visual representation.
+	//
+	// Supported types: int, string.
+	//
+	// Values:
+	//   - 0 (NumberEditor) or "editor" - Displayed as an editor.
+	//   - 1 (NumberSlider) or "slider" - Displayed as a slider.
+	NumberPickerType PropertyName = "number-picker-type"
 
-	// NumberPickerMin is the constant for the "number-picker-min" property tag.
-	// The "number-picker-min" int property sets the minimum value of NumberPicker. The default value is 0.
-	NumberPickerMin = "number-picker-min"
+	// NumberPickerMin is the constant for "number-picker-min" property tag.
+	//
+	// Used by NumberPicker.
+	// Set the minimum value. The default value is 0.
+	//
+	// Supported types: float, int, string.
+	//
+	// Internal type is float, other types converted to it during assignment.
+	NumberPickerMin PropertyName = "number-picker-min"
 
-	// NumberPickerMax is the constant for the "number-picker-max" property tag.
-	// The "number-picker-max" int property sets the maximum value of NumberPicker. The default value is 1.
-	NumberPickerMax = "number-picker-max"
+	// NumberPickerMax is the constant for "number-picker-max" property tag.
+	//
+	// Used by NumberPicker.
+	// Set the maximum value. The default value is 1.
+	//
+	// Supported types: float, int, string.
+	//
+	// Internal type is float, other types converted to it during assignment.
+	NumberPickerMax PropertyName = "number-picker-max"
 
-	// NumberPickerStep is the constant for the "number-picker-step" property tag.
-	// The "number-picker-step" int property sets the value change step of NumberPicker
-	NumberPickerStep = "number-picker-step"
+	// NumberPickerStep is the constant for "number-picker-step" property tag.
+	//
+	// Used by NumberPicker.
+	// Set the value change step.
+	//
+	// Supported types: float, int, string.
+	//
+	// Internal type is float, other types converted to it during assignment.
+	NumberPickerStep PropertyName = "number-picker-step"
 
-	// NumberPickerValue is the constant for the "number-picker-value" property tag.
-	// The "number-picker-value" int property sets the current value of NumberPicker. The default value is 0.
-	NumberPickerValue = "number-picker-value"
+	// NumberPickerValue is the constant for "number-picker-value" property tag.
+	//
+	// Used by NumberPicker.
+	// Current value. The default value is 0.
+	//
+	// Supported types: float, int, string.
+	//
+	// Internal type is float, other types converted to it during assignment.
+	NumberPickerValue PropertyName = "number-picker-value"
+
+	// NumberPickerValue is the constant for "number-picker-value" property tag.
+	//
+	// Used by NumberPicker.
+	// Precision of displaying fractional part in editor. The default value is 0 (not used).
+	//
+	// Supported types: int, int8...int64, uint, uint8...uint64, string.
+	//
+	// Internal type is float, other types converted to it during assignment.
+	NumberPickerPrecision PropertyName = "number-picker-precision"
 )
 
+// Constants which describe values of the "number-picker-type" property of a [NumberPicker]
 const (
 	// NumberEditor - type of NumberPicker. NumberPicker is presented by editor
 	NumberEditor = 0
@@ -42,15 +103,13 @@ const (
 	NumberSlider = 1
 )
 
-// NumberPicker - NumberPicker view
+// NumberPicker represents a NumberPicker view
 type NumberPicker interface {
 	View
 }
 
 type numberPickerData struct {
 	viewData
-	dataList
-	numberChangedListeners []func(NumberPicker, float64, float64)
 }
 
 // NewNumberPicker create new NumberPicker object and return it
@@ -62,165 +121,102 @@ func NewNumberPicker(session Session, params Params) NumberPicker {
 }
 
 func newNumberPicker(session Session) View {
-	return NewNumberPicker(session, nil)
+	return new(numberPickerData)
 }
 
 func (picker *numberPickerData) init(session Session) {
 	picker.viewData.init(session)
 	picker.tag = "NumberPicker"
 	picker.hasHtmlDisabled = true
-	picker.numberChangedListeners = []func(NumberPicker, float64, float64){}
-	picker.dataListInit()
-}
-
-func (picker *numberPickerData) String() string {
-	return getViewString(picker, nil)
+	picker.normalize = normalizeNumberPickerTag
+	picker.set = picker.setFunc
+	picker.changed = picker.propertyChanged
 }
 
 func (picker *numberPickerData) Focusable() bool {
 	return true
 }
 
-func (picker *numberPickerData) normalizeTag(tag string) string {
-	tag = strings.ToLower(tag)
+func normalizeNumberPickerTag(tag PropertyName) PropertyName {
+	tag = defaultNormalize(tag)
 	switch tag {
-	case Type, Min, Max, Step, Value:
+	case Type, Min, Max, Step, Value, "precision":
 		return "number-picker-" + tag
 	}
 
-	return picker.normalizeDataListTag(tag)
+	return normalizeDataListTag(tag)
 }
 
-func (picker *numberPickerData) Remove(tag string) {
-	picker.remove(picker.normalizeTag(tag))
-}
-
-func (picker *numberPickerData) remove(tag string) {
+func (picker *numberPickerData) setFunc(tag PropertyName, value any) []PropertyName {
 	switch tag {
 	case NumberChangedEvent:
-		if len(picker.numberChangedListeners) > 0 {
-			picker.numberChangedListeners = []func(NumberPicker, float64, float64){}
-			picker.propertyChangedEvent(tag)
-		}
+		return setTwoArgEventListener[NumberPicker, float64](picker, tag, value)
 
 	case NumberPickerValue:
-		oldValue := GetNumberPickerValue(picker)
-		picker.viewData.remove(tag)
-		if oldValue != 0 {
-			if picker.created {
-				picker.session.callFunc("setInputValue", picker.htmlID(), 0)
-			}
-			for _, listener := range picker.numberChangedListeners {
-				listener(picker, 0, oldValue)
-			}
-			picker.propertyChangedEvent(tag)
-		}
-
-	case DataList:
-		if len(picker.dataList.dataList) > 0 {
-			picker.setDataList(picker, []string{}, true)
-		}
-
-	default:
-		picker.viewData.remove(tag)
-		picker.propertyChanged(tag)
-	}
-}
-
-func (picker *numberPickerData) Set(tag string, value any) bool {
-	return picker.set(picker.normalizeTag(tag), value)
-}
-
-func (picker *numberPickerData) set(tag string, value any) bool {
-	if value == nil {
-		picker.remove(tag)
-		return true
-	}
-
-	switch tag {
-	case NumberChangedEvent:
-		listeners, ok := valueToEventWithOldListeners[NumberPicker, float64](value)
-		if !ok {
-			notCompatibleType(tag, value)
-			return false
-		} else if listeners == nil {
-			listeners = []func(NumberPicker, float64, float64){}
-		}
-		picker.numberChangedListeners = listeners
-		picker.propertyChangedEvent(tag)
-		return true
-
-	case NumberPickerValue:
-		oldValue := GetNumberPickerValue(picker)
+		picker.setRaw("old-number", GetNumberPickerValue(picker))
 		min, max := GetNumberPickerMinMax(picker)
-		if picker.setFloatProperty(NumberPickerValue, value, min, max) {
-			if f, ok := floatProperty(picker, NumberPickerValue, picker.Session(), min); ok && f != oldValue {
-				newValue, _ := floatTextProperty(picker, NumberPickerValue, picker.Session(), min)
-				if picker.created {
-					picker.session.callFunc("setInputValue", picker.htmlID(), newValue)
-				}
-				for _, listener := range picker.numberChangedListeners {
-					listener(picker, f, oldValue)
-				}
-				picker.propertyChangedEvent(tag)
-			}
-			return true
-		}
+
+		return setFloatProperty(picker, NumberPickerValue, value, min, max)
 
 	case DataList:
-		return picker.setDataList(picker, value, picker.created)
-
-	default:
-		if picker.viewData.set(tag, value) {
-			picker.propertyChanged(tag)
-			return true
-		}
+		return setDataList(picker, value, "")
 	}
-	return false
+
+	return picker.viewData.setFunc(tag, value)
 }
 
-func (picker *numberPickerData) propertyChanged(tag string) {
-	if picker.created {
-		switch tag {
-		case NumberPickerType:
-			if GetNumberPickerType(picker) == NumberSlider {
-				picker.session.updateProperty(picker.htmlID(), "type", "range")
-			} else {
-				picker.session.updateProperty(picker.htmlID(), "type", "number")
-			}
-
-		case NumberPickerMin:
-			min, _ := GetNumberPickerMinMax(picker)
-			picker.session.updateProperty(picker.htmlID(), Min, strconv.FormatFloat(min, 'f', -1, 32))
-
-		case NumberPickerMax:
-			_, max := GetNumberPickerMinMax(picker)
-			picker.session.updateProperty(picker.htmlID(), Max, strconv.FormatFloat(max, 'f', -1, 32))
-
-		case NumberPickerStep:
-			if step := GetNumberPickerStep(picker); step > 0 {
-				picker.session.updateProperty(picker.htmlID(), Step, strconv.FormatFloat(step, 'f', -1, 32))
-			} else {
-				picker.session.updateProperty(picker.htmlID(), Step, "any")
-			}
-		}
+func (picker *numberPickerData) numberFormat() string {
+	if precission := GetNumberPickerPrecision(picker); precission > 0 {
+		return fmt.Sprintf("%%.%df", precission)
 	}
+	return "%g"
 }
 
-func (picker *numberPickerData) Get(tag string) any {
-	return picker.get(picker.normalizeTag(tag))
-}
-
-func (picker *numberPickerData) get(tag string) any {
+func (picker *numberPickerData) propertyChanged(tag PropertyName) {
 	switch tag {
-	case NumberChangedEvent:
-		return picker.numberChangedListeners
+	case NumberPickerType:
+		if GetNumberPickerType(picker) == NumberSlider {
+			picker.Session().updateProperty(picker.htmlID(), "type", "range")
+		} else {
+			picker.Session().updateProperty(picker.htmlID(), "type", "number")
+		}
 
-	case DataList:
-		return picker.dataList.dataList
+	case NumberPickerMin:
+		min, _ := GetNumberPickerMinMax(picker)
+		picker.Session().updateProperty(picker.htmlID(), "min", fmt.Sprintf(picker.numberFormat(), min))
+
+	case NumberPickerMax:
+		_, max := GetNumberPickerMinMax(picker)
+		picker.Session().updateProperty(picker.htmlID(), "max", fmt.Sprintf(picker.numberFormat(), max))
+
+	case NumberPickerStep:
+		if step := GetNumberPickerStep(picker); step > 0 {
+			picker.Session().updateProperty(picker.htmlID(), "step", fmt.Sprintf(picker.numberFormat(), step))
+		} else {
+			picker.Session().updateProperty(picker.htmlID(), "step", "any")
+		}
+
+	case NumberPickerValue:
+		value := GetNumberPickerValue(picker)
+		format := picker.numberFormat()
+		picker.Session().callFunc("setInputValue", picker.htmlID(), fmt.Sprintf(format, value))
+
+		if listeners := GetNumberChangedListeners(picker); len(listeners) > 0 {
+			old := 0.0
+			if val := picker.getRaw("old-number"); val != nil {
+				if n, ok := val.(float64); ok {
+					old = n
+				}
+			}
+			if old != value {
+				for _, listener := range listeners {
+					listener(picker, value, old)
+				}
+			}
+		}
 
 	default:
-		return picker.viewData.get(tag)
+		picker.viewData.propertyChanged(tag)
 	}
 }
 
@@ -229,7 +225,10 @@ func (picker *numberPickerData) htmlTag() string {
 }
 
 func (picker *numberPickerData) htmlSubviews(self View, buffer *strings.Builder) {
-	picker.dataListHtmlSubviews(self, buffer)
+	dataListHtmlSubviews(self, buffer, func(text string, session Session) string {
+		text, _ = session.resolveConstants(text)
+		return text
+	})
 }
 
 func (picker *numberPickerData) htmlProperties(self View, buffer *strings.Builder) {
@@ -241,38 +240,39 @@ func (picker *numberPickerData) htmlProperties(self View, buffer *strings.Builde
 		buffer.WriteString(` type="number"`)
 	}
 
+	format := picker.numberFormat()
 	min, max := GetNumberPickerMinMax(picker)
 	if min != math.Inf(-1) {
 		buffer.WriteString(` min="`)
-		buffer.WriteString(strconv.FormatFloat(min, 'f', -1, 64))
+		buffer.WriteString(fmt.Sprintf(format, min))
 		buffer.WriteByte('"')
 	}
 
 	if max != math.Inf(1) {
 		buffer.WriteString(` max="`)
-		buffer.WriteString(strconv.FormatFloat(max, 'f', -1, 64))
+		buffer.WriteString(fmt.Sprintf(format, max))
 		buffer.WriteByte('"')
 	}
 
 	step := GetNumberPickerStep(picker)
 	if step != 0 {
 		buffer.WriteString(` step="`)
-		buffer.WriteString(strconv.FormatFloat(step, 'f', -1, 64))
+		buffer.WriteString(fmt.Sprintf(format, step))
 		buffer.WriteByte('"')
 	} else {
 		buffer.WriteString(` step="any"`)
 	}
 
 	buffer.WriteString(` value="`)
-	buffer.WriteString(strconv.FormatFloat(GetNumberPickerValue(picker), 'f', -1, 64))
+	buffer.WriteString(fmt.Sprintf(format, GetNumberPickerValue(picker)))
 	buffer.WriteByte('"')
 
 	buffer.WriteString(` oninput="editViewInputEvent(this)"`)
 
-	picker.dataListHtmlProperties(picker, buffer)
+	dataListHtmlProperties(picker, buffer)
 }
 
-func (picker *numberPickerData) handleCommand(self View, command string, data DataObject) bool {
+func (picker *numberPickerData) handleCommand(self View, command PropertyName, data DataObject) bool {
 	switch command {
 	case "textChanged":
 		if text, ok := data.PropertyValue("text"); ok {
@@ -280,9 +280,12 @@ func (picker *numberPickerData) handleCommand(self View, command string, data Da
 				oldValue := GetNumberPickerValue(picker)
 				picker.properties[NumberPickerValue] = text
 				if value != oldValue {
-					for _, listener := range picker.numberChangedListeners {
+					for _, listener := range GetNumberChangedListeners(picker) {
 						listener(picker, value, oldValue)
 					}
+					if listener, ok := picker.changeListener[NumberPickerValue]; ok {
+						listener(picker, NumberPickerValue)
+					}
 				}
 			}
 		}
@@ -303,12 +306,8 @@ func GetNumberPickerType(view View, subviewID ...string) int {
 // GetNumberPickerMinMax returns the min and max value of NumberPicker subview.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetNumberPickerMinMax(view View, subviewID ...string) (float64, float64) {
-	var pickerType int
-	if len(subviewID) > 0 && subviewID[0] != "" {
-		pickerType = GetNumberPickerType(view, subviewID[0])
-	} else {
-		pickerType = GetNumberPickerType(view)
-	}
+	view = getSubview(view, subviewID)
+	pickerType := GetNumberPickerType(view)
 
 	var defMin, defMax float64
 	if pickerType == NumberSlider {
@@ -319,8 +318,8 @@ func GetNumberPickerMinMax(view View, subviewID ...string) (float64, float64) {
 		defMax = math.Inf(1)
 	}
 
-	min := floatStyledProperty(view, subviewID, NumberPickerMin, defMin)
-	max := floatStyledProperty(view, subviewID, NumberPickerMax, defMax)
+	min := floatStyledProperty(view, nil, NumberPickerMin, defMin)
+	max := floatStyledProperty(view, nil, NumberPickerMax, defMax)
 
 	if min > max {
 		return max, min
@@ -331,14 +330,10 @@ func GetNumberPickerMinMax(view View, subviewID ...string) (float64, float64) {
 // GetNumberPickerStep returns the value changing step of NumberPicker subview.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetNumberPickerStep(view View, subviewID ...string) float64 {
-	var max float64
-	if len(subviewID) > 0 && subviewID[0] != "" {
-		_, max = GetNumberPickerMinMax(view, subviewID[0])
-	} else {
-		_, max = GetNumberPickerMinMax(view)
-	}
+	view = getSubview(view, subviewID)
+	_, max := GetNumberPickerMinMax(view)
 
-	result := floatStyledProperty(view, subviewID, NumberPickerStep, 0)
+	result := floatStyledProperty(view, nil, NumberPickerStep, 0)
 	if result > max {
 		return max
 	}
@@ -348,20 +343,20 @@ func GetNumberPickerStep(view View, subviewID ...string) float64 {
 // GetNumberPickerValue returns the value of NumberPicker subview.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetNumberPickerValue(view View, subviewID ...string) float64 {
-	var min float64
-	if len(subviewID) > 0 && subviewID[0] != "" {
-		min, _ = GetNumberPickerMinMax(view, subviewID[0])
-	} else {
-		min, _ = GetNumberPickerMinMax(view)
-	}
-
-	result := floatStyledProperty(view, subviewID, NumberPickerValue, min)
-	return result
+	view = getSubview(view, subviewID)
+	min, _ := GetNumberPickerMinMax(view)
+	return floatStyledProperty(view, nil, NumberPickerValue, min)
 }
 
 // GetNumberChangedListeners returns the NumberChangedListener list of an NumberPicker subview.
 // If there are no listeners then the empty list is returned
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetNumberChangedListeners(view View, subviewID ...string) []func(NumberPicker, float64, float64) {
-	return getEventWithOldListeners[NumberPicker, float64](view, subviewID, NumberChangedEvent)
+	return getTwoArgEventListeners[NumberPicker, float64](view, subviewID, NumberChangedEvent)
+}
+
+// GetNumberPickerPrecision returns the precision of displaying fractional part in editor of NumberPicker subview.
+// If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
+func GetNumberPickerPrecision(view View, subviewID ...string) int {
+	return intStyledProperty(view, subviewID, NumberPickerPrecision, 0)
 }

outline.go

@@ -5,35 +5,50 @@ import (
 	"strings"
 )
 
+// OutlineProperty defines a view's outside border
 type OutlineProperty interface {
 	Properties
 	stringWriter
 	fmt.Stringer
+
+	// ViewOutline returns style color and line width of an outline
 	ViewOutline(session Session) ViewOutline
 }
 
 type outlinePropertyData struct {
-	propertyList
+	dataProperty
 }
 
+// NewOutlineProperty creates the new OutlineProperty.
+//
+// The following properties can be used:
+//   - "color" (ColorTag) - Determines the line color (Color);
+//   - "width" (Width) -  Determines the line thickness (SizeUnit).
 func NewOutlineProperty(params Params) OutlineProperty {
 	outline := new(outlinePropertyData)
-	outline.properties = map[string]any{}
+	outline.init()
 	for tag, value := range params {
 		outline.Set(tag, value)
 	}
 	return outline
 }
 
+func (outline *outlinePropertyData) init() {
+	outline.propertyList.init()
+	outline.normalize = normalizeOutlineTag
+	outline.set = outlineSet
+	outline.supportedProperties = []PropertyName{Style, Width, ColorTag}
+}
+
 func (outline *outlinePropertyData) writeString(buffer *strings.Builder, indent string) {
 	buffer.WriteString("_{ ")
 	comma := false
-	for _, tag := range []string{Style, Width, ColorTag} {
+	for _, tag := range []PropertyName{Style, Width, ColorTag} {
 		if value, ok := outline.properties[tag]; ok {
 			if comma {
 				buffer.WriteString(", ")
 			}
-			buffer.WriteString(tag)
+			buffer.WriteString(string(tag))
 			buffer.WriteString(" = ")
 			writePropertyValue(buffer, BorderStyle, value, indent)
 			comma = true
@@ -47,46 +62,33 @@ func (outline *outlinePropertyData) String() string {
 	return runStringWriter(outline)
 }
 
-func (outline *outlinePropertyData) normalizeTag(tag string) string {
-	return strings.TrimPrefix(strings.ToLower(tag), "outline-")
+func normalizeOutlineTag(tag PropertyName) PropertyName {
+	tag = defaultNormalize(tag)
+	return PropertyName(strings.TrimPrefix(string(tag), "outline-"))
 }
 
-func (outline *outlinePropertyData) Remove(tag string) {
-	delete(outline.properties, outline.normalizeTag(tag))
-}
-
-func (outline *outlinePropertyData) Set(tag string, value any) bool {
-	if value == nil {
-		outline.Remove(tag)
-		return true
-	}
-
-	tag = outline.normalizeTag(tag)
+func outlineSet(properties Properties, tag PropertyName, value any) []PropertyName {
 	switch tag {
 	case Style:
-		return outline.setEnumProperty(Style, value, enumProperties[BorderStyle].values)
+		return setEnumProperty(properties, Style, value, enumProperties[BorderStyle].values)
 
 	case Width:
 		if width, ok := value.(SizeUnit); ok {
 			switch width.Type {
 			case SizeInFraction, SizeInPercent:
 				notCompatibleType(tag, value)
-				return false
+				return nil
 			}
 		}
-		return outline.setSizeProperty(Width, value)
+		return setSizeProperty(properties, Width, value)
 
 	case ColorTag:
-		return outline.setColorProperty(ColorTag, value)
+		return setColorProperty(properties, ColorTag, value)
 
 	default:
 		ErrorLogF(`"%s" property is not compatible with the OutlineProperty`, tag)
 	}
-	return false
-}
-
-func (outline *outlinePropertyData) Get(tag string) any {
-	return outline.propertyList.Get(outline.normalizeTag(tag))
+	return nil
 }
 
 func (outline *outlinePropertyData) ViewOutline(session Session) ViewOutline {
@@ -98,8 +100,13 @@ func (outline *outlinePropertyData) ViewOutline(session Session) ViewOutline {
 
 // ViewOutline describes parameters of a view border
 type ViewOutline struct {
+	// Style of the outline line
 	Style int
+
+	// Color of the outline line
 	Color Color
+
+	// Width of the outline line
 	Width SizeUnit
 }
 
@@ -118,7 +125,7 @@ func (outline ViewOutline) cssString(session Session) string {
 	return builder.finish()
 }
 
-func getOutline(properties Properties) OutlineProperty {
+func getOutlineProperty(properties Properties) OutlineProperty {
 	if value := properties.Get(Outline); value != nil {
 		if outline, ok := value.(OutlineProperty); ok {
 			return outline
@@ -128,30 +135,30 @@ func getOutline(properties Properties) OutlineProperty {
 	return nil
 }
 
-func (style *viewStyle) setOutline(value any) bool {
+func setOutlineProperty(properties Properties, value any) []PropertyName {
 	switch value := value.(type) {
 	case OutlineProperty:
-		style.properties[Outline] = value
+		properties.setRaw(Outline, value)
 
 	case ViewOutline:
-		style.properties[Outline] = NewOutlineProperty(Params{Style: value.Style, Width: value.Width, ColorTag: value.Color})
+		properties.setRaw(Outline, NewOutlineProperty(Params{Style: value.Style, Width: value.Width, ColorTag: value.Color}))
 
 	case ViewBorder:
-		style.properties[Outline] = NewOutlineProperty(Params{Style: value.Style, Width: value.Width, ColorTag: value.Color})
+		properties.setRaw(Outline, NewOutlineProperty(Params{Style: value.Style, Width: value.Width, ColorTag: value.Color}))
 
 	case DataObject:
 		outline := NewOutlineProperty(nil)
-		for _, tag := range []string{Style, Width, ColorTag} {
-			if text, ok := value.PropertyValue(tag); ok && text != "" {
+		for _, tag := range []PropertyName{Style, Width, ColorTag} {
+			if text, ok := value.PropertyValue(string(tag)); ok && text != "" {
 				outline.Set(tag, text)
 			}
 		}
-		style.properties[Outline] = outline
+		properties.setRaw(Outline, outline)
 
 	default:
 		notCompatibleType(Outline, value)
-		return false
+		return nil
 	}
 
-	return true
+	return []PropertyName{Outline}
 }

params.go

@@ -3,25 +3,29 @@ package rui
 import "sort"
 
 // Params defines a type of a parameters list
-type Params map[string]any
+type Params map[PropertyName]any
 
-func (params Params) Get(tag string) any {
+// Get returns a value of the property with name defined by the argument. The type of return value depends
+// on the property. If the property is not set then nil is returned.
+func (params Params) Get(tag PropertyName) any {
 	return params.getRaw(tag)
 }
 
-func (params Params) getRaw(tag string) any {
+func (params Params) getRaw(tag PropertyName) any {
 	if value, ok := params[tag]; ok {
 		return value
 	}
 	return nil
 }
 
-func (params Params) Set(tag string, value any) bool {
+// Set sets the value (second argument) of the property with name defined by the first argument.
+// Return "true" if the value has been set, in the opposite case "false" is returned and a description of an error is written to the log
+func (params Params) Set(tag PropertyName, value any) bool {
 	params.setRaw(tag, value)
 	return true
 }
 
-func (params Params) setRaw(tag string, value any) {
+func (params Params) setRaw(tag PropertyName, value any) {
 	if value != nil {
 		params[tag] = value
 	} else {
@@ -29,21 +33,30 @@ func (params Params) setRaw(tag string, value any) {
 	}
 }
 
-func (params Params) Remove(tag string) {
+// Remove removes the property with name defined by the argument from a map.
+func (params Params) Remove(tag PropertyName) {
 	delete(params, tag)
 }
 
+// Clear removes all properties from a map.
 func (params Params) Clear() {
 	for tag := range params {
 		delete(params, tag)
 	}
 }
 
-func (params Params) AllTags() []string {
-	tags := make([]string, 0, len(params))
+// AllTags returns a sorted slice of all properties.
+func (params Params) AllTags() []PropertyName {
+	tags := make([]PropertyName, 0, len(params))
 	for t := range params {
 		tags = append(tags, t)
 	}
-	sort.Strings(tags)
+	sort.Slice(tags, func(i, j int) bool {
+		return tags[i] < tags[j]
+	})
 	return tags
 }
+
+func (params Params) empty() bool {
+	return len(params) == 0
+}

path.go

@@ -2,9 +2,6 @@ package rui
 
 // Path is a path interface
 type Path interface {
-	// Reset erases the Path
-	Reset()
-
 	// MoveTo begins a new sub-path at the point specified by the given (x, y) coordinates
 	MoveTo(x, y float64)
 
@@ -14,123 +11,119 @@ type Path interface {
 
 	// ArcTo adds a circular arc to the current sub-path, using the given control points and radius.
 	// The arc is automatically connected to the path's latest point with a straight line, if necessary.
-	//   x0, y0 - coordinates of the first control point;
-	//   x1, y1 - coordinates of the second control point;
-	//   radius - the arc's radius. Must be non-negative.
+	//  - x0, y0 - coordinates of the first control point;
+	//  - x1, y1 - coordinates of the second control point;
+	//  - radius - the arc's radius. Must be non-negative.
 	ArcTo(x0, y0, x1, y1, radius float64)
 
 	// Arc adds a circular arc to the current sub-path.
-	//   x, y - coordinates of the arc's center;
-	//   radius - the arc's radius. Must be non-negative;
-	//   startAngle - the angle at which the arc starts, measured clockwise from the positive
+	//   - x, y - coordinates of the arc's center;
+	//   - radius - the arc's radius. Must be non-negative;
+	//   - startAngle - the angle at which the arc starts, measured clockwise from the positive
 	//                x-axis and expressed in radians.
-	//   endAngle - the angle at which the arc ends, measured clockwise from the positive
+	//   - endAngle - the angle at which the arc ends, measured clockwise from the positive
 	//                x-axis and expressed in radians.
-	//   clockwise - if true, causes the arc to be drawn clockwise between the start and end angles,
+	//   - clockwise - if true, causes the arc to be drawn clockwise between the start and end angles,
 	//               otherwise - counter-clockwise
 	Arc(x, y, radius, startAngle, endAngle float64, clockwise bool)
 
 	// BezierCurveTo adds a cubic Bézier curve to the current sub-path. The starting point is
 	// the latest point in the current path.
-	//   cp0x, cp0y - coordinates of the first control point;
-	//   cp1x, cp1y - coordinates of the second control point;
-	//   x, y - coordinates of the end point.
+	//   - cp0x, cp0y - coordinates of the first control point;
+	//   - cp1x, cp1y - coordinates of the second control point;
+	//   - x, y - coordinates of the end point.
 	BezierCurveTo(cp0x, cp0y, cp1x, cp1y, x, y float64)
 
 	// QuadraticCurveTo  adds a quadratic Bézier curve to the current sub-path.
-	//   cpx, cpy - coordinates of the control point;
-	//   x, y - coordinates of the end point.
+	//   - cpx, cpy - coordinates of the control point;
+	//   - x, y - coordinates of the end point.
 	QuadraticCurveTo(cpx, cpy, x, y float64)
 
 	// Ellipse adds an elliptical arc to the current sub-path
-	//   x, y - coordinates of the ellipse's center;
-	//   radiusX - the ellipse's major-axis radius. Must be non-negative;
-	//   radiusY - the ellipse's minor-axis radius. Must be non-negative;
-	//   rotation - the rotation of the ellipse, expressed in radians;
-	//   startAngle - the angle at which the ellipse starts, measured clockwise
+	//   - x, y - coordinates of the ellipse's center;
+	//   - radiusX - the ellipse's major-axis radius. Must be non-negative;
+	//   - radiusY - the ellipse's minor-axis radius. Must be non-negative;
+	//   - rotation - the rotation of the ellipse, expressed in radians;
+	//   - startAngle - the angle at which the ellipse starts, measured clockwise
 	//                from the positive x-axis and expressed in radians;
-	//   endAngle - the angle at which the ellipse ends, measured clockwise
+	//   - endAngle - the angle at which the ellipse ends, measured clockwise
 	//	            from the positive x-axis and expressed in radians.
-	//   clockwise - if true, draws the ellipse clockwise, otherwise draws counter-clockwise
+	//   - clockwise - if true, draws the ellipse clockwise, otherwise draws counter-clockwise
 	Ellipse(x, y, radiusX, radiusY, rotation, startAngle, endAngle float64, clockwise bool)
 
 	// Close adds a straight line from the current point to the start of the current sub-path.
 	// If the shape has already been closed or has only one point, this function does nothing.
 	Close()
 
-	create(session Session)
-}
-
-type pathElement struct {
-	funcName string
-	args     []any
+	obj() any
 }
 
 type pathData struct {
-	elements []pathElement
+	session Session
+	varName any
 }
 
 // NewPath creates a new empty Path
-func NewPath() Path {
+func (canvas *canvasData) NewPath() Path {
 	path := new(pathData)
-	path.Reset()
+	path.session = canvas.session
+	path.varName = canvas.session.createPath("")
 	return path
 }
 
-func (path *pathData) Reset() {
-	path.elements = []pathElement{
-		{funcName: "beginPath", args: []any{}},
-	}
+func (canvas *canvasData) NewPathFromSvg(data string) Path {
+	path := new(pathData)
+	path.session = canvas.session
+	path.varName = canvas.session.createPath(data)
+	return path
 }
 
 func (path *pathData) MoveTo(x, y float64) {
-	path.elements = append(path.elements, pathElement{funcName: "moveTo", args: []any{x, y}})
+	path.session.callCanvasVarFunc(path.varName, "moveTo", x, y)
 }
 
 func (path *pathData) LineTo(x, y float64) {
-	path.elements = append(path.elements, pathElement{funcName: "lineTo", args: []any{x, y}})
+	path.session.callCanvasVarFunc(path.varName, "lineTo", x, y)
 }
 
 func (path *pathData) ArcTo(x0, y0, x1, y1, radius float64) {
 	if radius > 0 {
-		path.elements = append(path.elements, pathElement{funcName: "arcTo", args: []any{x0, y0, x1, y1, radius}})
+		path.session.callCanvasVarFunc(path.varName, "arcTo", x0, y0, x1, y1, radius)
 	}
 }
 
 func (path *pathData) Arc(x, y, radius, startAngle, endAngle float64, clockwise bool) {
 	if radius > 0 {
 		if !clockwise {
-			path.elements = append(path.elements, pathElement{funcName: "arc", args: []any{x, y, radius, startAngle, endAngle, true}})
+			path.session.callCanvasVarFunc(path.varName, "arc", x, y, radius, startAngle, endAngle, true)
 		} else {
-			path.elements = append(path.elements, pathElement{funcName: "arc", args: []any{x, y, radius, startAngle, endAngle}})
+			path.session.callCanvasVarFunc(path.varName, "arc", x, y, radius, startAngle, endAngle)
 		}
 	}
 }
 
 func (path *pathData) BezierCurveTo(cp0x, cp0y, cp1x, cp1y, x, y float64) {
-	path.elements = append(path.elements, pathElement{funcName: "bezierCurveTo", args: []any{cp0x, cp0y, cp1x, cp1y, x, y}})
+	path.session.callCanvasVarFunc(path.varName, "bezierCurveTo", cp0x, cp0y, cp1x, cp1y, x, y)
 }
 
 func (path *pathData) QuadraticCurveTo(cpx, cpy, x, y float64) {
-	path.elements = append(path.elements, pathElement{funcName: "quadraticCurveTo", args: []any{cpx, cpy, x, y}})
+	path.session.callCanvasVarFunc(path.varName, "quadraticCurveTo", cpx, cpy, x, y)
 }
 
 func (path *pathData) Ellipse(x, y, radiusX, radiusY, rotation, startAngle, endAngle float64, clockwise bool) {
 	if radiusX > 0 && radiusY > 0 {
 		if !clockwise {
-			path.elements = append(path.elements, pathElement{funcName: "ellipse", args: []any{x, y, radiusX, radiusY, rotation, startAngle, endAngle, true}})
+			path.session.callCanvasVarFunc(path.varName, "ellipse", x, y, radiusX, radiusY, rotation, startAngle, endAngle, true)
 		} else {
-			path.elements = append(path.elements, pathElement{funcName: "ellipse", args: []any{x, y, radiusX, radiusY, rotation, startAngle, endAngle}})
+			path.session.callCanvasVarFunc(path.varName, "ellipse", x, y, radiusX, radiusY, rotation, startAngle, endAngle)
 		}
 	}
 }
 
 func (path *pathData) Close() {
-	path.elements = append(path.elements, pathElement{funcName: "close", args: []any{}})
+	path.session.callCanvasVarFunc(path.varName, "closePath")
 }
 
-func (path *pathData) create(session Session) {
-	for _, element := range path.elements {
-		session.callCanvasFunc(element.funcName, element.args...)
-	}
+func (path *pathData) obj() any {
+	return path.varName
 }

pointerEvents.go

@@ -1,54 +1,133 @@
 package rui
 
-import (
-	"strings"
-)
-
+// Constants for [View] specific pointer events properties
 const (
 	// PointerDown is the constant for "pointer-down" property tag.
-	// The "pointer-down" event is fired when a pointer becomes active. For mouse, it is fired when
-	// the device transitions from no buttons depressed to at least one button depressed.
-	// For touch, it is fired when physical contact is made with the digitizer.
-	// For pen, it is fired when the stylus makes physical contact with the digitizer.
-	// The main listener format: func(View, PointerEvent).
-	// The additional listener formats: func(PointerEvent), func(View), and func().
-	PointerDown = "pointer-down"
+	//
+	// Used by View.
+	// Fired when a pointer becomes active. For mouse, it is fired when the device transitions from no buttons depressed to at
+	// least one button depressed. For touch, it is fired when physical contact is made with the digitizer. For pen, it is
+	// fired when the stylus makes physical contact with the digitizer.
+	//
+	// General listener format:
+	//
+	//  func(view rui.View, event rui.PointerEvent)
+	//
+	// where:
+	//   - view - Interface of a view which generated this event,
+	//   - event - Pointer event.
+	//
+	// Allowed listener formats:
+	//
+	//  func(event rui.PointerEvent)
+	//  func(view rui.View)
+	//  func()
+	PointerDown PropertyName = "pointer-down"
 
 	// PointerUp is the constant for "pointer-up" property tag.
-	// The "pointer-up" event is fired when a pointer is no longer active.
-	// The main listener format: func(View, PointerEvent).
-	// The additional listener formats: func(PointerEvent), func(View), and func().
-	PointerUp = "pointer-up"
+	//
+	// Used by View.
+	// Is fired when a pointer is no longer active.
+	//
+	// General listener format:
+	//
+	//  func(view rui.View, event rui.PointerEvent)
+	//
+	// where:
+	//   - view - Interface of a view which generated this event,
+	//   - event - Pointer event.
+	//
+	// Allowed listener formats:
+	//
+	//  func(event rui.PointerEvent)
+	//  func(view rui.View)
+	//  func()
+	PointerUp PropertyName = "pointer-up"
 
 	// PointerMove is the constant for "pointer-move" property tag.
-	// The "pointer-move" event is fired when a pointer changes coordinates.
-	// The main listener format: func(View, PointerEvent).
-	// The additional listener formats: func(PointerEvent), func(View), and func().
-	PointerMove = "pointer-move"
+	//
+	// Used by View.
+	// Is fired when a pointer changes coordinates.
+	//
+	// General listener format:
+	//
+	//  func(view rui.View, event rui.PointerEvent)
+	//
+	// where:
+	//   - view - Interface of a view which generated this event,
+	//   - event - Pointer event.
+	//
+	// Allowed listener formats:
+	//
+	//  func(event rui.PointerEvent)
+	//  func(view rui.View)
+	//  func()
+	PointerMove PropertyName = "pointer-move"
 
 	// PointerCancel is the constant for "pointer-cancel" property tag.
-	// The "pointer-cancel" event is fired if the pointer will no longer be able to generate events
-	// (for example the related device is deactivated).
-	// The main listener format: func(View, PointerEvent).
-	// The additional listener formats: func(PointerEvent), func(View), and func().
-	PointerCancel = "pointer-cancel"
+	//
+	// Used by View.
+	// Is fired if the pointer will no longer be able to generate events (for example the related device is deactivated).
+	//
+	// General listener format:
+	//
+	//  func(view rui.View, event rui.PointerEvent)
+	//
+	// where:
+	//   - view - Interface of a view which generated this event,
+	//   - event - Pointer event.
+	//
+	// Allowed listener formats:
+	//
+	//  func(event rui.PointerEvent)
+	//  func(view rui.View)
+	//  func()
+	PointerCancel PropertyName = "pointer-cancel"
 
 	// PointerOut is the constant for "pointer-out" property tag.
-	// The "pointer-out" event is fired for several reasons including: pointing device is moved out
-	// of the hit test boundaries of an element; firing the pointerup event for a device
-	// that does not support hover (see "pointer-up"); after firing the pointercancel event (see "pointer-cancel");
-	// when a pen stylus leaves the hover range detectable by the digitizer.
-	// The main listener format: func(View, PointerEvent).
-	// The additional listener formats: func(PointerEvent), func(View), and func().
-	PointerOut = "pointer-out"
+	//
+	// Used by View.
+	// Is fired for several reasons including: pointing device is moved out of the hit test boundaries of an element; firing
+	// the "pointer-up" event for a device that does not support hover (see "pointer-up"); after firing the "pointer-cancel"
+	// event (see "pointer-cancel"); when a pen stylus leaves the hover range detectable by the digitizer.
+	//
+	// General listener format:
+	//
+	//  func(view rui.View, event rui.PointerEvent)
+	//
+	// where:
+	//   - view - Interface of a view which generated this event,
+	//   - event - Pointer event.
+	//
+	// Allowed listener formats:
+	//
+	//  func(event rui.PointerEvent)
+	//  func(view rui.View)
+	//  func()
+	PointerOut PropertyName = "pointer-out"
 
 	// PointerOver is the constant for "pointer-over" property tag.
-	// The "pointer-over" event is fired when a pointing device is moved into an view's hit test boundaries.
-	// The main listener format: func(View, PointerEvent).
-	// The additional listener formats: func(PointerEvent), func(View), and func().
-	PointerOver = "pointer-over"
+	//
+	// Used by View.
+	// Is fired when a pointing device is moved into an view's hit test boundaries.
+	//
+	// General listener format:
+	//
+	//  func(view rui.View, event rui.PointerEvent)
+	//
+	// where:
+	//   - view - Interface of a view which generated this event,
+	//   - event - Pointer event.
+	//
+	// Allowed listener formats:
+	//
+	//  func(event rui.PointerEvent)
+	//  func(view rui.View)
+	//  func()
+	PointerOver PropertyName = "pointer-over"
 )
 
+// PointerEvent represent a stylus events. Also inherit [MouseEvent] attributes
 type PointerEvent struct {
 	MouseEvent
 
@@ -87,57 +166,6 @@ type PointerEvent struct {
 	IsPrimary bool
 }
 
-var pointerEvents = map[string]struct{ jsEvent, jsFunc string }{
-	PointerDown:   {jsEvent: "onpointerdown", jsFunc: "pointerDownEvent"},
-	PointerUp:     {jsEvent: "onpointerup", jsFunc: "pointerUpEvent"},
-	PointerMove:   {jsEvent: "onpointermove", jsFunc: "pointerMoveEvent"},
-	PointerCancel: {jsEvent: "onpointercancel", jsFunc: "pointerCancelEvent"},
-	PointerOut:    {jsEvent: "onpointerout", jsFunc: "pointerOutEvent"},
-	PointerOver:   {jsEvent: "onpointerover", jsFunc: "pointerOverEvent"},
-}
-
-func (view *viewData) setPointerListener(tag string, value any) bool {
-	listeners, ok := valueToEventListeners[View, PointerEvent](value)
-	if !ok {
-		notCompatibleType(tag, value)
-		return false
-	}
-
-	if listeners == nil {
-		view.removePointerListener(tag)
-	} else if js, ok := pointerEvents[tag]; ok {
-		view.properties[tag] = listeners
-		if view.created {
-			view.session.updateProperty(view.htmlID(), js.jsEvent, js.jsFunc+"(this, event)")
-		}
-	} else {
-		return false
-	}
-	return true
-}
-
-func (view *viewData) removePointerListener(tag string) {
-	delete(view.properties, tag)
-	if view.created {
-		if js, ok := pointerEvents[tag]; ok {
-			view.session.removeProperty(view.htmlID(), js.jsEvent)
-		}
-	}
-}
-
-func pointerEventsHtml(view View, buffer *strings.Builder) {
-	for tag, js := range pointerEvents {
-		if value := view.getRaw(tag); value != nil {
-			if listeners, ok := value.([]func(View, PointerEvent)); ok && len(listeners) > 0 {
-				buffer.WriteString(js.jsEvent)
-				buffer.WriteString(`="`)
-				buffer.WriteString(js.jsFunc)
-				buffer.WriteString(`(this, event)" `)
-			}
-		}
-	}
-}
-
 func (event *PointerEvent) init(data DataObject) {
 	event.MouseEvent.init(data)
 
@@ -154,8 +182,8 @@ func (event *PointerEvent) init(data DataObject) {
 	event.IsPrimary = dataBoolProperty(data, "isPrimary")
 }
 
-func handlePointerEvents(view View, tag string, data DataObject) {
-	listeners := getEventListeners[View, PointerEvent](view, nil, tag)
+func handlePointerEvents(view View, tag PropertyName, data DataObject) {
+	listeners := getOneArgEventListeners[View, PointerEvent](view, nil, tag)
 	if len(listeners) == 0 {
 		return
 	}
@@ -171,35 +199,35 @@ func handlePointerEvents(view View, tag string, data DataObject) {
 // GetPointerDownListeners returns the "pointer-down" listener list. If there are no listeners then the empty list is returned.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetPointerDownListeners(view View, subviewID ...string) []func(View, PointerEvent) {
-	return getEventListeners[View, PointerEvent](view, subviewID, PointerDown)
+	return getOneArgEventListeners[View, PointerEvent](view, subviewID, PointerDown)
 }
 
 // GetPointerUpListeners returns the "pointer-up" listener list. If there are no listeners then the empty list is returned.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetPointerUpListeners(view View, subviewID ...string) []func(View, PointerEvent) {
-	return getEventListeners[View, PointerEvent](view, subviewID, PointerUp)
+	return getOneArgEventListeners[View, PointerEvent](view, subviewID, PointerUp)
 }
 
 // GetPointerMoveListeners returns the "pointer-move" listener list. If there are no listeners then the empty list is returned.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetPointerMoveListeners(view View, subviewID ...string) []func(View, PointerEvent) {
-	return getEventListeners[View, PointerEvent](view, subviewID, PointerMove)
+	return getOneArgEventListeners[View, PointerEvent](view, subviewID, PointerMove)
 }
 
 // GetPointerCancelListeners returns the "pointer-cancel" listener list. If there are no listeners then the empty list is returned.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetPointerCancelListeners(view View, subviewID ...string) []func(View, PointerEvent) {
-	return getEventListeners[View, PointerEvent](view, subviewID, PointerCancel)
+	return getOneArgEventListeners[View, PointerEvent](view, subviewID, PointerCancel)
 }
 
 // GetPointerOverListeners returns the "pointer-over" listener list. If there are no listeners then the empty list is returned.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetPointerOverListeners(view View, subviewID ...string) []func(View, PointerEvent) {
-	return getEventListeners[View, PointerEvent](view, subviewID, PointerOver)
+	return getOneArgEventListeners[View, PointerEvent](view, subviewID, PointerOver)
 }
 
 // GetPointerOutListeners returns the "pointer-out" listener list. If there are no listeners then the empty list is returned.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetPointerOutListeners(view View, subviewID ...string) []func(View, PointerEvent) {
-	return getEventListeners[View, PointerEvent](view, subviewID, PointerOut)
+	return getOneArgEventListeners[View, PointerEvent](view, subviewID, PointerOut)
 }

popup.go

@@ -1,64 +1,216 @@
 package rui
 
 import (
+	"fmt"
 	"strings"
 )
 
+// Constants for [Popup] specific properties and events
 const (
-	// Title is the constant for the "title" property tag.
-	// The "title" property is defined the Popup/Tabs title
-	Title = "title"
+	// Title is the constant for "title" property tag.
+	//
+	// Used by Popup, TabsLayout.
+	//
+	// Usage in Popup:
+	// Define the title.
+	//
+	// Supported types: string.
+	//
+	// Usage in TabsLayout:
+	// Set the title of the tab. The property is set for the child view of TabsLayout.
+	//
+	// Supported types: string.
+	Title PropertyName = "title"
 
-	// TitleStyle is the constant for the "title-style" property tag.
-	// The "title-style" string property is used to set the title style of the Popup.
-	TitleStyle = "title-style"
+	// TitleStyle is the constant for "title-style" property tag.
+	//
+	// Used by Popup.
+	// Set popup title style. Default title style is "ruiPopupTitle".
+	//
+	// Supported types: string.
+	TitleStyle PropertyName = "title-style"
 
-	// CloseButton is the constant for the "close-button" property tag.
-	// The "close-button" bool property allow to add the close button to the Popup.
-	// Setting this property to "true" adds a window close button to the title bar (the default value is "false").
-	CloseButton = "close-button"
+	// CloseButton is the constant for "close-button" property tag.
+	//
+	// Used by Popup.
+	// Controls whether a close button can be added to the popup. Default value is false.
+	//
+	// Supported types: bool, int, string.
+	//
+	// Values:
+	//   - true, 1, "true", "yes", "on", "1" - Close button will be added to a title bar of a window.
+	//   - false, 0, "false", "no", "off", "0" - Popup without a close button.
+	CloseButton PropertyName = "close-button"
 
-	// OutsideClose is the constant for the "outside-close" property tag.
-	// The "outside-close" is a bool property. If it is set to "true",
-	// then clicking outside the popup window automatically calls the Dismiss() method.
-	OutsideClose = "outside-close"
+	// OutsideClose is the constant for "outside-close" property tag.
+	//
+	// Used by Popup.
+	// Controls whether popup can be closed by clicking outside of the window. Default value is false.
+	//
+	// Supported types: bool, int, string.
+	//
+	// Values:
+	//   - true, 1, "true", "yes", "on", "1" - Clicking outside the popup window will automatically call the Dismiss() method.
+	//   - false, 0, "false", "no", "off", "0" - Clicking outside the popup window has no effect.
+	OutsideClose PropertyName = "outside-close"
 
-	// Buttons is the constant for the "buttons" property tag.
-	// Using the "buttons" property you can add buttons that will be placed at the bottom of the Popup.
-	// The "buttons" property can be assigned the following data types: PopupButton and []PopupButton
-	Buttons = "buttons"
+	// Buttons is the constant for "buttons" property tag.
+	//
+	// Used by Popup.
+	// Buttons that will be placed at the bottom of the popup.
+	//
+	// Supported types: PopupButton, []PopupButton.
+	//
+	// Internal type is []PopupButton, other types converted to it during assignment.
+	// See PopupButton description for more details.
+	Buttons PropertyName = "buttons"
 
-	// ButtonsAlign is the constant for the "buttons-align" property tag.
-	// The "buttons-align" int property is used for set the horizontal alignment of Popup buttons.
-	// Valid values: LeftAlign (0), RightAlign (1), CenterAlign (2), and StretchAlign (3)
-	ButtonsAlign = "buttons-align"
+	// ButtonsAlign is the constant for "buttons-align" property tag.
+	//
+	// Used by Popup.
+	// Set the horizontal alignment of popup buttons.
+	//
+	// Supported types: int, string.
+	//
+	// Values:
+	//   - 0 (LeftAlign) or "left" - Left alignment.
+	//   - 1 (RightAlign) or "right" - Right alignment.
+	//   - 2 (CenterAlign) or "center" - Center alignment.
+	//   - 3 (StretchAlign) or "stretch" - Width alignment.
+	ButtonsAlign PropertyName = "buttons-align"
 
-	// DismissEvent is the constant for the "dismiss-event" property tag.
-	// The "dismiss-event" event is used to track the closing of the Popup.
-	// It occurs after the Popup disappears from the screen.
-	// The main listener for this event has the following format: func(Popup)
-	DismissEvent = "dismiss-event"
+	// DismissEvent is the constant for "dismiss-event" property tag.
+	//
+	// Used by Popup.
+	// Used to track the closing state of the Popup. It occurs after the Popup disappears from the screen.
+	//
+	// General listener format:
+	//
+	//  func(popup rui.Popup)
+	//
+	// where:
+	// popup - Interface of a popup which generated this event.
+	//
+	// Allowed listener formats:
+	//
+	//  func()
+	DismissEvent PropertyName = "dismiss-event"
 
-	// Arrow is the constant for the "arrow" property tag.
-	// Using the "popup-arrow" int property you can add ...
-	Arrow = "arrow"
+	// Arrow is the constant for "arrow" property tag.
+	//
+	// Used by Popup.
+	// Add an arrow to popup. Default value is "none".
+	//
+	// Supported types: int, string.
+	//
+	// Values:
+	//   - 0 (NoneArrow) or "none" - No arrow.
+	//   - 1 (TopArrow) or "top" - Arrow at the top side of the pop-up window.
+	//   - 2 (RightArrow) or "right" - Arrow on the right side of the pop-up window.
+	//   - 3 (BottomArrow) or "bottom" - Arrow at the bottom of the pop-up window.
+	//   - 4 (LeftArrow) or "left" - Arrow on the left side of the pop-up window.
+	Arrow PropertyName = "arrow"
 
-	// ArrowAlign is the constant for the "arrow-align" property tag.
-	// The "arrow-align" int property is used for set the horizontal alignment of the Popup arrow.
-	// Valid values: LeftAlign (0), RightAlign (1), TopAlign (0), BottomAlign (1), CenterAlign (2)
-	ArrowAlign = "arrow-align"
+	// ArrowAlign is the constant for "arrow-align" property tag.
+	//
+	// Used by Popup.
+	// Set the horizontal alignment of the popup arrow. Default value is "center".
+	//
+	// Supported types: int, string.
+	//
+	// Values:
+	//   - 0 (TopAlign/LeftAlign) or "top" - Top/left alignment.
+	//   - 1 (BottomAlign/RightAlign) or "bottom" - Bottom/right alignment.
+	//   - 2 (CenterAlign) or "center" - Center alignment.
+	ArrowAlign PropertyName = "arrow-align"
 
-	// ArrowSize is the constant for the "arrow-size" property tag.
-	// The "arrow-size" SizeUnit property is used for set the size (length) of the Popup arrow.
-	ArrowSize = "arrow-size"
+	// ArrowSize is the constant for "arrow-size" property tag.
+	//
+	// Used by Popup.
+	// Set the size(length) of the popup arrow. Default value is 16px defined by @ruiArrowSize constant.
+	//
+	// Supported types: SizeUnit, SizeFunc, string, float, int.
+	//
+	// Internal type is SizeUnit, other types converted to it during assignment.
+	// See SizeUnit description for more details.
+	ArrowSize PropertyName = "arrow-size"
 
-	// ArrowWidth is the constant for the "arrow-width" property tag.
-	// The "arrow-width" SizeUnit property is used for set the width of the Popup arrow.
-	ArrowWidth = "arrow-width"
+	// ArrowWidth is the constant for "arrow-width" property tag.
+	//
+	// Used by Popup.
+	// Set the width of the popup arrow. Default value is 16px defined by @ruiArrowWidth constant.
+	//
+	// Supported types: SizeUnit, SizeFunc, string, float, int.
+	//
+	// Internal type is SizeUnit, other types converted to it during assignment.
+	// See SizeUnit description for more details.
+	ArrowWidth PropertyName = "arrow-width"
 
-	// ArrowOffset is the constant for the "arrow-offset" property tag.
-	// The "arrow-offset" SizeUnit property is used for set the offset of the Popup arrow.
-	ArrowOffset = "arrow-offset"
+	// ShowTransform is the constant for "show-transform" property tag.
+	//
+	// Used by Popup.
+	// Specify start translation, scale and rotation over x, y and z axes as well as a distortion
+	// for an animated Popup showing/hidding.
+	//
+	// Supported types: TransformProperty, string.
+	//
+	// See TransformProperty description for more details.
+	//
+	// Conversion rules:
+	//   - TransformProperty - stored as is, no conversion performed.
+	//   - string - string representation of Transform interface. Example:
+	//
+	//	"_{ translate-x = 10px, scale-y = 1.1}"
+	ShowTransform PropertyName = "show-transform"
+
+	// ShowDuration is the constant for "show-duration" property tag.
+	//
+	// Used by Popup.
+	// Sets the length of time in seconds that a Popup show/hide animation takes to complete.
+	//
+	// Supported types: float, int, string.
+	//
+	// Internal type is float, other types converted to it during assignment.
+	ShowDuration PropertyName = "show-duration"
+
+	// ShowTiming is the constant for "show-timing" property tag.
+	//
+	// Used by Popup.
+	// Set how a Popup show/hide animation progresses through the duration of each cycle.
+	//
+	// Supported types: string.
+	//
+	// Values:
+	//   - "ease" (EaseTiming) - Speed increases towards the middle and slows down at the end.
+	//   - "ease-in" (EaseInTiming) - Speed is slow at first, but increases in the end.
+	//   - "ease-out" (EaseOutTiming) - Speed is fast at first, but decreases in the end.
+	//   - "ease-in-out" (EaseInOutTiming) - Speed is slow at first, but quickly increases and at the end it decreases again.
+	//   - "linear" (LinearTiming) - Constant speed.
+	//   - "step(n)" (StepTiming(n int) function) - Timing function along stepCount stops along the transition, displaying each stop for equal lengths of time.
+	//   - "cubic-bezier(x1, y1, x2, y2)" (CubicBezierTiming(x1, y1, x2, y2 float64) function) - Cubic-Bezier curve timing function. x1 and x2 must be in the range [0, 1].
+	ShowTiming PropertyName = "show-timing"
+
+	// ShowOpacity is the constant for "show-opacity" property tag.
+	//
+	// Used by Popup.
+	// In [1..0] range sets the start opacity of Popup show animation (the finish animation opacity is 1).
+	// Opacity is the degree to which content behind the view is hidden, and is the opposite of transparency.
+	//
+	// Supported types: float, int, string.
+	//
+	// Internal type is float, other types converted to it during assignment.
+	ShowOpacity PropertyName = "show-opacity"
+
+	// ArrowOffset is the constant for "arrow-offset" property tag.
+	//
+	// Used by Popup.
+	// Set the offset of the popup arrow.
+	//
+	// Supported types: SizeUnit, SizeFunc, string, float, int.
+	//
+	// Internal type is SizeUnit, other types converted to it during assignment.
+	// See SizeUnit description for more details.
+	ArrowOffset PropertyName = "arrow-offset"
 
 	// NoneArrow is value of the popup "arrow" property: no arrow
 	NoneArrow = 0
@@ -78,42 +230,68 @@ const (
 	// LeftArrow is value of the popup "arrow" property:
 	// Arrow on the left side of the pop-up window
 	LeftArrow = 4
+)
 
+// Constants which are used as a values of [PopupButtonType] variables
+const (
 	// NormalButton is the constant of the popup button type: the normal button
 	NormalButton PopupButtonType = 0
+
 	// DefaultButton is the constant of the popup button type: button that fires when the "Enter" key is pressed
 	DefaultButton PopupButtonType = 1
+
 	// CancelButton is the constant of the popup button type: button that fires when the "Escape" key is pressed
 	CancelButton PopupButtonType = 2
 )
 
+// PopupButtonType represent popup button type
 type PopupButtonType int
 
 // PopupButton describes a button that will be placed at the bottom of the window.
 type PopupButton struct {
-	Title   string
-	Type    PopupButtonType
+	// Title of the button
+	Title string
+
+	// Type of the button
+	Type PopupButtonType
+
+	// OnClick is the handler function that gets called when the button is pressed
 	OnClick func(Popup)
 }
 
-// Popup interface
+// Popup represents a Popup view
 type Popup interface {
+	// View returns a content view of the popup
 	View() View
+
+	// Session returns current client session
 	Session() Session
+
+	// Show displays a popup
 	Show()
+
+	// Dismiss closes a popup
 	Dismiss()
+
 	onDismiss()
 	html(buffer *strings.Builder)
 	viewByHTMLID(id string) View
 	keyEvent(event KeyEvent) bool
+	showAnimation()
+	dissmissAnimation(listener func(PropertyName)) bool
 }
 
 type popupData struct {
-	layerView       View
-	view            View
+	layerView       GridLayout
+	popupView       GridLayout
+	contentView     View
 	buttons         []PopupButton
 	cancelable      bool
 	dismissListener []func(Popup)
+	showTransform   TransformProperty
+	showOpacity     float64
+	showDuration    float64
+	showTiming      string
 }
 
 type popupManager struct {
@@ -191,7 +369,7 @@ func (arrow *popupArrow) createView(popupView View) View {
 
 	params := Params{BackgroundColor: GetBackgroundColor(popupView)}
 
-	if shadow := GetViewShadows(popupView); shadow != nil {
+	if shadow := GetShadowProperty(popupView); shadow != nil {
 		params[Shadow] = shadow
 	}
 
@@ -203,28 +381,28 @@ func (arrow *popupArrow) createView(popupView View) View {
 	case TopArrow:
 		params[Row] = 0
 		params[Column] = 1
-		params[Clip] = PolygonClip([]any{"0%", "100%", "50%", "0%", "100%", "100%"})
+		params[Clip] = NewPolygonClip([]any{"0%", "100%", "50%", "0%", "100%", "100%"})
 		params[Width] = arrow.width
 		params[Height] = arrow.size
 
 	case RightArrow:
 		params[Row] = 1
 		params[Column] = 0
-		params[Clip] = PolygonClip([]any{"0%", "0%", "100%", "50%", "0%", "100%"})
+		params[Clip] = NewPolygonClip([]any{"0%", "0%", "100%", "50%", "0%", "100%"})
 		params[Width] = arrow.size
 		params[Height] = arrow.width
 
 	case BottomArrow:
 		params[Row] = 0
 		params[Column] = 1
-		params[Clip] = PolygonClip([]any{"0%", "0%", "50%", "100%", "100%", "0%"})
+		params[Clip] = NewPolygonClip([]any{"0%", "0%", "50%", "100%", "100%", "0%"})
 		params[Width] = arrow.width
 		params[Height] = arrow.size
 
 	case LeftArrow:
 		params[Row] = 1
 		params[Column] = 0
-		params[Clip] = PolygonClip([]any{"100%", "0%", "0%", "50%", "100%", "100%"})
+		params[Clip] = NewPolygonClip([]any{"100%", "0%", "0%", "50%", "100%", "100%"})
 		params[Width] = arrow.size
 		params[Height] = arrow.width
 	}
@@ -284,39 +462,15 @@ func (arrow *popupArrow) createView(popupView View) View {
 	return NewGridLayout(session, params)
 }
 
-func (popup *popupData) init(view View, popupParams Params) {
-	popup.view = view
-	popup.cancelable = false
-	session := view.Session()
+func (popup *popupData) layerCellWidth(arrowLocation int, popupParams Params, session Session) []SizeUnit {
 
-	columnCount := 3
-	rowCount := 3
-	popupRow := 1
-	popupColumn := 1
-	arrow := popupArrow{
-		row:    1,
-		column: 1,
-		align:  CenterAlign,
-	}
-
-	switch arrow.location, _ = enumProperty(popupParams, Arrow, session, NoneArrow); arrow.location {
-	case TopArrow:
-		rowCount = 4
-		popupRow = 2
-
-	case BottomArrow:
-		rowCount = 4
-		arrow.row = 2
-
-	case LeftArrow:
+	var columnCount int
+	switch arrowLocation {
+	case LeftArrow, RightArrow:
 		columnCount = 4
-		popupColumn = 2
-
-	case RightArrow:
-		columnCount = 4
-		arrow.column = 2
 
 	default:
+		columnCount = 3
 	}
 
 	cellWidth := make([]SizeUnit, columnCount)
@@ -331,6 +485,19 @@ func (popup *popupData) init(view View, popupParams Params) {
 		cellWidth[0] = Fr(1)
 		cellWidth[columnCount-1] = Fr(1)
 	}
+	return cellWidth
+}
+
+func (popup *popupData) layerCellHeight(arrowLocation int, popupParams Params, session Session) []SizeUnit {
+
+	var rowCount int
+	switch arrowLocation {
+	case TopArrow, BottomArrow:
+		rowCount = 4
+
+	default:
+		rowCount = 3
+	}
 
 	cellHeight := make([]SizeUnit, rowCount)
 	switch vAlign, _ := enumProperty(popupParams, VerticalAlign, session, CenterAlign); vAlign {
@@ -345,16 +512,47 @@ func (popup *popupData) init(view View, popupParams Params) {
 		cellHeight[rowCount-1] = Fr(1)
 	}
 
+	return cellHeight
+}
+
+func (popup *popupData) init(view View, popupParams Params) {
+	popup.contentView = view
+	popup.cancelable = false
+	session := view.Session()
+
+	popupRow := 1
+	popupColumn := 1
+	arrow := popupArrow{
+		row:    1,
+		column: 1,
+		align:  CenterAlign,
+	}
+
+	switch arrow.location, _ = enumProperty(popupParams, Arrow, session, NoneArrow); arrow.location {
+	case TopArrow:
+		popupRow = 2
+
+	case BottomArrow:
+		arrow.row = 2
+
+	case LeftArrow:
+		popupColumn = 2
+
+	case RightArrow:
+		arrow.column = 2
+	}
+
 	layerParams := Params{
 		Style:      "ruiPopupLayer",
 		MaxWidth:   Percent(100),
 		MaxHeight:  Percent(100),
-		CellWidth:  cellWidth,
-		CellHeight: cellHeight,
+		CellWidth:  popup.layerCellWidth(arrow.location, popupParams, session),
+		CellHeight: popup.layerCellHeight(arrow.location, popupParams, session),
 	}
 
 	params := Params{
 		Style:               "ruiPopup",
+		ID:                  "ruiPopup",
 		Row:                 popupRow,
 		Column:              popupColumn,
 		MaxWidth:            Percent(100),
@@ -362,7 +560,7 @@ func (popup *popupData) init(view View, popupParams Params) {
 		CellVerticalAlign:   StretchAlign,
 		CellHorizontalAlign: StretchAlign,
 		ClickEvent:          func(View) {},
-		Shadow: NewShadowWithParams(Params{
+		Shadow: NewShadowProperty(Params{
 			SpreadRadius: Px(4),
 			Blur:         Px(16),
 			ColorTag:     "@ruiPopupShadow",
@@ -370,10 +568,14 @@ func (popup *popupData) init(view View, popupParams Params) {
 	}
 
 	var closeButton View = nil
-	outsideClose := false
-	buttons := []PopupButton{}
-	titleStyle := "ruiPopupTitle"
 	var title View = nil
+	outsideClose := false
+	popup.buttons = []PopupButton{}
+	titleStyle := "ruiPopupTitle"
+
+	popup.showOpacity = 1.0
+	popup.showDuration = 1.0
+	popup.showTiming = "easy"
 
 	for tag, value := range popupParams {
 		if value != nil {
@@ -419,10 +621,10 @@ func (popup *popupData) init(view View, popupParams Params) {
 			case Buttons:
 				switch value := value.(type) {
 				case PopupButton:
-					buttons = []PopupButton{value}
+					popup.buttons = []PopupButton{value}
 
 				case []PopupButton:
-					buttons = value
+					popup.buttons = value
 				}
 
 			case Title:
@@ -447,7 +649,7 @@ func (popup *popupData) init(view View, popupParams Params) {
 				}
 
 			case DismissEvent:
-				if listeners, ok := valueToNoParamListeners[Popup](value); ok {
+				if listeners, ok := valueToNoArgEventListeners[Popup](value); ok {
 					if listeners != nil {
 						popup.dismissListener = listeners
 					}
@@ -474,13 +676,36 @@ func (popup *popupData) init(view View, popupParams Params) {
 			case ArrowOffset:
 				arrow.off, _ = sizeProperty(popupParams, ArrowOffset, session)
 
+			case ShowOpacity:
+				if opacity, _ := floatProperty(popupParams, ShowOpacity, session, 1); opacity >= 0 && opacity < 1 {
+					popup.showOpacity = opacity
+				}
+
+			case ShowTransform:
+				if transform := valueToTransformProperty(value); transform != nil && !transform.empty() {
+					popup.showTransform = transform
+				}
+
+			case ShowDuration:
+				if duration, _ := floatProperty(popupParams, ShowDuration, session, 1); duration > 0 {
+					popup.showDuration = duration
+				}
+
+			case ShowTiming:
+				if text, ok := value.(string); ok {
+					text, _ = session.resolveConstants(text)
+					if isTimingFunctionValid(text) {
+						popup.showTiming = text
+					}
+				}
+
 			default:
 				params[tag] = value
 			}
 		}
 	}
 
-	popupView := NewGridLayout(view.Session(), params)
+	popup.popupView = NewGridLayout(view.Session(), params)
 
 	var popupCellHeight []SizeUnit
 	viewRow := 0
@@ -492,7 +717,7 @@ func (popup *popupData) init(view View, popupParams Params) {
 		if closeButton != nil {
 			titleContent = append(titleContent, closeButton)
 		}
-		popupView.Append(NewGridLayout(session, Params{
+		popup.popupView.Append(NewGridLayout(session, Params{
 			Row:               0,
 			Style:             titleStyle,
 			CellWidth:         []any{Fr(1), AutoSize()},
@@ -508,10 +733,9 @@ func (popup *popupData) init(view View, popupParams Params) {
 	}
 
 	view.Set(Row, viewRow)
-	popupView.Append(view)
+	popup.popupView.Append(view)
 
-	popup.buttons = buttons
-	if buttonCount := len(buttons); buttonCount > 0 {
+	if buttonCount := len(popup.buttons); buttonCount > 0 {
 		buttonsAlign, _ := enumProperty(params, ButtonsAlign, session, RightAlign)
 		popupCellHeight = append(popupCellHeight, AutoSize())
 		gap, _ := sizeConstant(session, "ruiPopupButtonGap")
@@ -528,7 +752,7 @@ func (popup *popupData) init(view View, popupParams Params) {
 			buttonsPanel.Set(Margin, gap)
 		}
 
-		for i, button := range buttons {
+		for i, button := range popup.buttons {
 			title := button.Title
 			if title == "" && button.Type == CancelButton {
 				title = "Cancel"
@@ -555,33 +779,82 @@ func (popup *popupData) init(view View, popupParams Params) {
 			buttonsPanel.Append(buttonView)
 		}
 
-		popupView.Append(NewGridLayout(session, Params{
+		popup.popupView.Append(NewGridLayout(session, Params{
 			Row:                 viewRow + 1,
 			CellHorizontalAlign: buttonsAlign,
 			Content:             buttonsPanel,
 		}))
 	}
 
-	popupView.Set(CellHeight, popupCellHeight)
+	popup.popupView.Set(CellHeight, popupCellHeight)
 
 	if arrow.location != NoneArrow {
-		layerParams[Content] = []View{popupView, arrow.createView(popupView)}
+		layerParams[Content] = []View{popup.popupView, arrow.createView(popup.popupView)}
 	} else {
-		layerParams[Content] = []View{popupView}
+		layerParams[Content] = []View{popup.popupView}
 	}
 
 	popup.layerView = NewGridLayout(session, layerParams)
+
+	if popup.showOpacity != 1 || popup.showTransform != nil {
+		animation := NewAnimationProperty(Params{
+			Duration:       popup.showDuration,
+			TimingFunction: popup.showTiming,
+		})
+		if popup.showOpacity != 1 {
+			popup.popupView.Set(Opacity, popup.showOpacity)
+			popup.popupView.SetTransition(Opacity, animation)
+		}
+		if popup.showTransform != nil {
+			popup.popupView.Set(Transform, popup.showTransform)
+			popup.popupView.SetTransition(Transform, animation)
+		}
+	} else {
+		session.updateCSSProperty("ruiPopupLayer", "transition", "")
+	}
+
 	if outsideClose {
 		popup.layerView.Set(ClickEvent, popup.cancel)
 	}
 }
 
-func (popup popupData) View() View {
-	return popup.view
+func (popup *popupData) showAnimation() {
+	if popup.showOpacity != 1 || popup.showTransform != nil {
+		htmlID := popup.popupView.htmlID()
+		session := popup.Session()
+		if popup.showOpacity != 1 {
+			session.updateCSSProperty(htmlID, string(Opacity), "1")
+		}
+		if popup.showTransform != nil {
+			session.updateCSSProperty(htmlID, string(Transform), "")
+		}
+	}
+}
+
+func (popup *popupData) dissmissAnimation(listener func(PropertyName)) bool {
+	if popup.showOpacity != 1 || popup.showTransform != nil {
+		session := popup.Session()
+		popup.popupView.Set(TransitionEndEvent, listener)
+		popup.popupView.Set(TransitionCancelEvent, listener)
+
+		htmlID := popup.popupView.htmlID()
+		if popup.showOpacity != 1 {
+			session.updateCSSProperty(htmlID, string(Opacity), fmt.Sprintf("%.2f", popup.showOpacity))
+		}
+		if popup.showTransform != nil {
+			session.updateCSSProperty(htmlID, string(Transform), popup.showTransform.transformCSS(session))
+		}
+		return true
+	}
+	return false
+}
+
+func (popup *popupData) View() View {
+	return popup.contentView
 }
 
 func (popup *popupData) Session() Session {
-	return popup.view.Session()
+	return popup.contentView.Session()
 }
 
 func (popup *popupData) cancel() {
@@ -596,9 +869,6 @@ func (popup *popupData) cancel() {
 
 func (popup *popupData) Dismiss() {
 	popup.Session().popupManager().dismissPopup(popup)
-	for _, listener := range popup.dismissListener {
-		listener(popup)
-	}
 }
 
 func (popup *popupData) Show() {
@@ -606,8 +876,7 @@ func (popup *popupData) Show() {
 }
 
 func (popup *popupData) html(buffer *strings.Builder) {
-
-	viewHTML(popup.layerView, buffer)
+	viewHTML(popup.layerView, buffer, "")
 }
 
 func (popup *popupData) viewByHTMLID(id string) View {
@@ -615,6 +884,8 @@ func (popup *popupData) viewByHTMLID(id string) View {
 }
 
 func (popup *popupData) onDismiss() {
+	popup.Session().callFunc("removeView", popup.layerView.htmlID())
+
 	for _, listener := range popup.dismissListener {
 		listener(popup)
 	}
@@ -683,7 +954,7 @@ func (manager *popupManager) showPopup(popup Popup) {
 	}
 
 	session := popup.Session()
-	if manager.popups == nil || len(manager.popups) == 0 {
+	if len(manager.popups) == 0 {
 		manager.popups = []Popup{popup}
 	} else {
 		manager.popups = append(manager.popups, popup)
@@ -695,6 +966,7 @@ func (manager *popupManager) showPopup(popup Popup) {
 	session.updateCSSProperty("ruiTooltipLayer", "opacity", "0")
 	session.updateCSSProperty("ruiPopupLayer", "visibility", "visible")
 	session.updateCSSProperty("ruiRoot", "pointer-events", "none")
+	popup.showAnimation()
 }
 
 func (manager *popupManager) dismissPopup(popup Popup) {
@@ -708,31 +980,37 @@ func (manager *popupManager) dismissPopup(popup Popup) {
 		return
 	}
 
-	session := popup.Session()
-	if manager.popups[count-1] == popup {
-		if count == 1 {
-			manager.popups = []Popup{}
-			session.updateCSSProperty("ruiRoot", "pointer-events", "auto")
-			session.updateCSSProperty("ruiPopupLayer", "visibility", "hidden")
-			session.updateInnerHTML("ruiPopupLayer", "")
-		} else {
-			manager.popups = manager.popups[:count-1]
-			manager.updatePopupLayerInnerHTML(session)
+	index := -1
+	for n, p := range manager.popups {
+		if p == popup {
+			index = n
+			break
 		}
-		popup.onDismiss()
+	}
+
+	if index < 0 {
 		return
 	}
 
-	for n, p := range manager.popups {
-		if p == popup {
-			if n == 0 {
-				manager.popups = manager.popups[1:]
+	session := popup.Session()
+	listener := func(PropertyName) {
+		if index == count-1 {
+			if count == 1 {
+				manager.popups = []Popup{}
+				session.updateCSSProperty("ruiRoot", "pointer-events", "auto")
+				session.updateCSSProperty("ruiPopupLayer", "visibility", "hidden")
 			} else {
-				manager.popups = append(manager.popups[:n], manager.popups[n+1:]...)
+				manager.popups = manager.popups[:count-1]
 			}
-			manager.updatePopupLayerInnerHTML(session)
-			popup.onDismiss()
-			return
+		} else if index == 0 {
+			manager.popups = manager.popups[1:]
+		} else {
+			manager.popups = append(manager.popups[:index], manager.popups[index+1:]...)
 		}
+		popup.onDismiss()
+	}
+
+	if !popup.dissmissAnimation(listener) {
+		listener("")
 	}
 }

popupUtils.go

@@ -17,7 +17,9 @@ func ShowMessage(title, text string, session Session) {
 }
 
 // ShowQuestion displays a message with the given title and text and two buttons "Yes" and "No".
+//
 // When the "Yes" button is clicked, the message is closed and the onYes function is called (if it is not nil).
+//
 // When the "No" button is pressed, the message is closed and the onNo function is called (if it is not nil).
 func ShowQuestion(title, text string, session Session, onYes func(), onNo func()) {
 	textView := NewTextView(session, Params{
@@ -57,6 +59,7 @@ func ShowQuestion(title, text string, session Session, onYes func(), onNo func()
 }
 
 // ShowCancellableQuestion displays a message with the given title and text and three buttons "Yes", "No" and "Cancel".
+//
 // When the "Yes", "No" or "Cancel" button is pressed, the message is closed and the onYes, onNo or onCancel function
 // (if it is not nil) is called, respectively.
 func ShowCancellableQuestion(title, text string, session Session, onYes func(), onNo func(), onCancel func()) {
@@ -152,9 +155,12 @@ func (popup *popupMenuData) IsListItemEnabled(index int) bool {
 	return true
 }
 
-// PopupMenuResult is the constant for the "popup-menu-result" property tag.
-// The "popup-menu-result" property sets the function (format: func(int)) to be called when
-// a menu item of popup menu is selected.
+// PopupMenuResult is the constant for "popup-menu-result" property tag.
+//
+// Used by `Popup`.
+// Set the function to be called when the menu item of popup menu is selected.
+//
+// Supported types: `func(index int)`.
 const PopupMenuResult = "popup-menu-result"
 
 // ShowMenu displays the menu. Menu items are set using the Items property.

progressBar.go

@@ -5,12 +5,30 @@ import (
 	"strings"
 )
 
+// Constants for [ProgressBar] specific properties and events
 const (
-	ProgressBarMax   = "progress-max"
-	ProgressBarValue = "progress-value"
+	// ProgressBarMax is the constant for "progress-max" property tag.
+	//
+	// Used by ProgressBar.
+	// Maximum value, default is 1.
+	//
+	// Supported types: float, int, string.
+	//
+	// Internal type is float, other types converted to it during assignment.
+	ProgressBarMax PropertyName = "progress-max"
+
+	// ProgressBarValue is the constant for "progress-value" property tag.
+	//
+	// Used by ProgressBar.
+	// Current value, default is 0.
+	//
+	// Supported types: float, int, string.
+	//
+	// Internal type is float, other types converted to it during assignment.
+	ProgressBarValue PropertyName = "progress-value"
 )
 
-// ProgressBar - ProgressBar view
+// ProgressBar represents a ProgressBar view
 type ProgressBar interface {
 	View
 }
@@ -28,20 +46,18 @@ func NewProgressBar(session Session, params Params) ProgressBar {
 }
 
 func newProgressBar(session Session) View {
-	return NewProgressBar(session, nil)
+	return new(progressBarData)
 }
 
 func (progress *progressBarData) init(session Session) {
 	progress.viewData.init(session)
 	progress.tag = "ProgressBar"
+	progress.normalize = normalizeProgressBarTag
+	progress.changed = progress.propertyChanged
 }
 
-func (progress *progressBarData) String() string {
-	return getViewString(progress, nil)
-}
-
-func (progress *progressBarData) normalizeTag(tag string) string {
-	tag = strings.ToLower(tag)
+func normalizeProgressBarTag(tag PropertyName) PropertyName {
+	tag = defaultNormalize(tag)
 	switch tag {
 	case Max, "progress-bar-max", "progressbar-max":
 		return ProgressBarMax
@@ -52,45 +68,22 @@ func (progress *progressBarData) normalizeTag(tag string) string {
 	return tag
 }
 
-func (progress *progressBarData) Remove(tag string) {
-	progress.remove(progress.normalizeTag(tag))
-}
+func (progress *progressBarData) propertyChanged(tag PropertyName) {
 
-func (progress *progressBarData) remove(tag string) {
-	progress.viewData.remove(tag)
-	progress.propertyChanged(tag)
-}
+	switch tag {
+	case ProgressBarMax:
+		progress.Session().updateProperty(progress.htmlID(), "max",
+			strconv.FormatFloat(GetProgressBarMax(progress), 'f', -1, 32))
 
-func (progress *progressBarData) propertyChanged(tag string) {
-	if progress.created {
-		switch tag {
-		case ProgressBarMax:
-			progress.session.updateProperty(progress.htmlID(), Max,
-				strconv.FormatFloat(GetProgressBarMax(progress), 'f', -1, 32))
+	case ProgressBarValue:
+		progress.Session().updateProperty(progress.htmlID(), "value",
+			strconv.FormatFloat(GetProgressBarValue(progress), 'f', -1, 32))
 
-		case ProgressBarValue:
-			progress.session.updateProperty(progress.htmlID(), Value,
-				strconv.FormatFloat(GetProgressBarValue(progress), 'f', -1, 32))
-		}
+	default:
+		progress.viewData.propertyChanged(tag)
 	}
 }
 
-func (progress *progressBarData) Set(tag string, value any) bool {
-	return progress.set(progress.normalizeTag(tag), value)
-}
-
-func (progress *progressBarData) set(tag string, value any) bool {
-	if progress.viewData.set(tag, value) {
-		progress.propertyChanged(tag)
-		return true
-	}
-	return false
-}
-
-func (progress *progressBarData) Get(tag string) any {
-	return progress.get(progress.normalizeTag(tag))
-}
-
 func (progress *progressBarData) htmlTag() string {
 	return "progress"
 }

properties.go

@@ -9,71 +9,96 @@ import (
 type Properties interface {
 	// Get returns a value of the property with name defined by the argument.
 	// The type of return value depends on the property. If the property is not set then nil is returned.
-	Get(tag string) any
-	getRaw(tag string) any
+	Get(tag PropertyName) any
+	getRaw(tag PropertyName) any
 
 	// Set sets the value (second argument) of the property with name defined by the first argument.
 	// Return "true" if the value has been set, in the opposite case "false" are returned and
 	// a description of the error is written to the log
-	Set(tag string, value any) bool
-	setRaw(tag string, value any)
+	Set(tag PropertyName, value any) bool
+	setRaw(tag PropertyName, value any)
 
 	// Remove removes the property with name defined by the argument
-	Remove(tag string)
+	Remove(tag PropertyName)
 
 	// Clear removes all properties
 	Clear()
 
 	// AllTags returns an array of the set properties
-	AllTags() []string
+	AllTags() []PropertyName
+
+	empty() bool
 }
 
 type propertyList struct {
-	properties map[string]any
+	properties map[PropertyName]any
+	normalize  func(PropertyName) PropertyName
+	//getFunc    func(PropertyName) any
+	//set        func(Properties, PropertyName, any) []PropertyName
+	//remove     func(Properties, PropertyName) []PropertyName
+}
+
+type dataProperty struct {
+	propertyList
+	supportedProperties []PropertyName
+	get                 func(Properties, PropertyName) any
+	set                 func(Properties, PropertyName, any) []PropertyName
+	remove              func(Properties, PropertyName) []PropertyName
+}
+
+func defaultNormalize(tag PropertyName) PropertyName {
+	return PropertyName(strings.ToLower(strings.Trim(string(tag), " \t")))
 }
 
 func (properties *propertyList) init() {
-	properties.properties = map[string]any{}
+	properties.properties = map[PropertyName]any{}
+	properties.normalize = defaultNormalize
+	//properties.getFunc = properties.getRaw
+	//properties.set = propertiesSet
+	//properties.remove = propertiesRemove
 }
 
-func (properties *propertyList) Get(tag string) any {
-	return properties.getRaw(strings.ToLower(tag))
+func (properties *propertyList) empty() bool {
+	return len(properties.properties) == 0
 }
 
-func (properties *propertyList) getRaw(tag string) any {
+func (properties *propertyList) getRaw(tag PropertyName) any {
 	if value, ok := properties.properties[tag]; ok {
 		return value
 	}
 	return nil
 }
 
-func (properties *propertyList) setRaw(tag string, value any) {
-	properties.properties[tag] = value
-}
-
-func (properties *propertyList) Remove(tag string) {
-	delete(properties.properties, strings.ToLower(tag))
-}
-
-func (properties *propertyList) remove(tag string) {
-	delete(properties.properties, tag)
-}
-
-func (properties *propertyList) Clear() {
-	properties.properties = map[string]any{}
-}
-
-func (properties *propertyList) AllTags() []string {
-	tags := make([]string, 0, len(properties.properties))
-	for t := range properties.properties {
-		tags = append(tags, t)
+func (properties *propertyList) setRaw(tag PropertyName, value any) {
+	if value == nil {
+		delete(properties.properties, tag)
+	} else {
+		properties.properties[tag] = value
 	}
-	sort.Strings(tags)
+}
+
+/*
+	func (properties *propertyList) Remove(tag PropertyName) {
+		properties.remove(properties, properties.normalize(tag))
+	}
+*/
+func (properties *propertyList) Clear() {
+	properties.properties = map[PropertyName]any{}
+}
+
+func (properties *propertyList) AllTags() []PropertyName {
+	tags := make([]PropertyName, 0, len(properties.properties))
+	for tag := range properties.properties {
+		tags = append(tags, tag)
+	}
+	sort.Slice(tags, func(i, j int) bool {
+		return tags[i] < tags[j]
+	})
 	return tags
 }
 
 func (properties *propertyList) writeToBuffer(buffer *strings.Builder,
-	indent string, objectTag string, tags []string) {
+	indent string, objectTag string, tags []PropertyName) {
 
 	buffer.WriteString(objectTag)
 	buffer.WriteString(" {\n")
@@ -83,7 +108,7 @@ func (properties *propertyList) writeToBuffer(buffer *strings.Builder,
 	for _, tag := range tags {
 		if value, ok := properties.properties[tag]; ok {
 			buffer.WriteString(indent2)
-			buffer.WriteString(tag)
+			buffer.WriteString(string(tag))
 			buffer.WriteString(" = ")
 			writePropertyValue(buffer, tag, value, indent2)
 			buffer.WriteString(",\n")
@@ -100,14 +125,41 @@ func parseProperties(properties Properties, object DataObject) {
 		if node := object.Property(i); node != nil {
 			switch node.Type() {
 			case TextNode:
-				properties.Set(node.Tag(), node.Text())
+				properties.Set(PropertyName(node.Tag()), node.Text())
 
 			case ObjectNode:
-				properties.Set(node.Tag(), node.Object())
+				properties.Set(PropertyName(node.Tag()), node.Object())
 
 			case ArrayNode:
-				properties.Set(node.Tag(), node.ArrayElements())
+				properties.Set(PropertyName(node.Tag()), node.ArrayElements())
 			}
 		}
 	}
 }
+
+func propertiesGet(properties Properties, tag PropertyName) any {
+	return properties.getRaw(tag)
+}
+
+func propertiesRemove(properties Properties, tag PropertyName) []PropertyName {
+	if properties.getRaw(tag) == nil {
+		return []PropertyName{}
+	}
+	properties.setRaw(tag, nil)
+	return []PropertyName{tag}
+}
+
+func (data *dataProperty) init() {
+	data.propertyList.init()
+	data.get = propertiesGet
+	data.set = propertiesSet
+	data.remove = propertiesRemove
+}
+
+func (data *dataProperty) Get(tag PropertyName) any {
+	return propertiesGet(data, data.normalize(tag))
+}
+
+func (data *dataProperty) Remove(tag PropertyName) {
+	data.remove(data, data.normalize(tag))
+}

propertyGet.go

@@ -6,7 +6,7 @@ import (
 	"strings"
 )
 
-func stringProperty(properties Properties, tag string, session Session) (string, bool) {
+func stringProperty(properties Properties, tag PropertyName, session Session) (string, bool) {
 	if value := properties.getRaw(tag); value != nil {
 		if text, ok := value.(string); ok {
 			return session.resolveConstants(text)
@@ -15,7 +15,7 @@ func stringProperty(properties Properties, tag string, session Session) (string,
 	return "", false
 }
 
-func imageProperty(properties Properties, tag string, session Session) (string, bool) {
+func imageProperty(properties Properties, tag PropertyName, session Session) (string, bool) {
 	if value := properties.getRaw(tag); value != nil {
 		if text, ok := value.(string); ok {
 			if text != "" && text[0] == '@' {
@@ -61,11 +61,11 @@ func valueToSizeUnit(value any, session Session) (SizeUnit, bool) {
 	return AutoSize(), false
 }
 
-func sizeProperty(properties Properties, tag string, session Session) (SizeUnit, bool) {
+func sizeProperty(properties Properties, tag PropertyName, session Session) (SizeUnit, bool) {
 	return valueToSizeUnit(properties.getRaw(tag), session)
 }
 
-func angleProperty(properties Properties, tag string, session Session) (AngleUnit, bool) {
+func angleProperty(properties Properties, tag PropertyName, session Session) (AngleUnit, bool) {
 	if value := properties.getRaw(tag); value != nil {
 		switch value := value.(type) {
 		case AngleUnit:
@@ -98,11 +98,11 @@ func valueToColor(value any, session Session) (Color, bool) {
 	return Color(0), false
 }
 
-func colorProperty(properties Properties, tag string, session Session) (Color, bool) {
+func colorProperty(properties Properties, tag PropertyName, session Session) (Color, bool) {
 	return valueToColor(properties.getRaw(tag), session)
 }
 
-func valueToEnum(value any, tag string, session Session, defaultValue int) (int, bool) {
+func valueToEnum(value any, tag PropertyName, session Session, defaultValue int) (int, bool) {
 	if value != nil {
 		values := enumProperties[tag].values
 		switch value := value.(type) {
@@ -165,7 +165,7 @@ func enumStringToInt(value string, enumValues []string, logError bool) (int, boo
 	return 0, false
 }
 
-func enumProperty(properties Properties, tag string, session Session, defaultValue int) (int, bool) {
+func enumProperty(properties Properties, tag PropertyName, session Session, defaultValue int) (int, bool) {
 	return valueToEnum(properties.getRaw(tag), tag, session, defaultValue)
 }
 
@@ -194,7 +194,7 @@ func valueToBool(value any, session Session) (bool, bool) {
 	return false, false
 }
 
-func boolProperty(properties Properties, tag string, session Session) (bool, bool) {
+func boolProperty(properties Properties, tag PropertyName, session Session) (bool, bool) {
 	return valueToBool(properties.getRaw(tag), session)
 }
 
@@ -224,7 +224,7 @@ func valueToInt(value any, session Session, defaultValue int) (int, bool) {
 	return defaultValue, false
 }
 
-func intProperty(properties Properties, tag string, session Session, defaultValue int) (int, bool) {
+func intProperty(properties Properties, tag PropertyName, session Session, defaultValue int) (int, bool) {
 	return valueToInt(properties.getRaw(tag), session, defaultValue)
 }
 
@@ -248,7 +248,7 @@ func valueToFloat(value any, session Session, defaultValue float64) (float64, bo
 	return defaultValue, false
 }
 
-func floatProperty(properties Properties, tag string, session Session, defaultValue float64) (float64, bool) {
+func floatProperty(properties Properties, tag PropertyName, session Session, defaultValue float64) (float64, bool) {
 	return valueToFloat(properties.getRaw(tag), session, defaultValue)
 }
 
@@ -272,7 +272,7 @@ func valueToFloatText(value any, session Session, defaultValue float64) (string,
 	return fmt.Sprintf("%g", defaultValue), false
 }
 
-func floatTextProperty(properties Properties, tag string, session Session, defaultValue float64) (string, bool) {
+func floatTextProperty(properties Properties, tag PropertyName, session Session, defaultValue float64) (string, bool) {
 	return valueToFloatText(properties.getRaw(tag), session, defaultValue)
 }
 
@@ -297,6 +297,6 @@ func valueToRange(value any, session Session) (Range, bool) {
 	return Range{}, false
 }
 
-func rangeProperty(properties Properties, tag string, session Session) (Range, bool) {
+func rangeProperty(properties Properties, tag PropertyName, session Session) (Range, bool) {
 	return valueToRange(properties.getRaw(tag), session)
 }

propertySet.go

@@ -6,7 +6,7 @@ import (
 	"strings"
 )
 
-var colorProperties = []string{
+var colorProperties = []PropertyName{
 	ColorTag,
 	BackgroundColor,
 	TextColor,
@@ -19,9 +19,10 @@ var colorProperties = []string{
 	OutlineColor,
 	TextLineColor,
 	ColorPickerValue,
+	AccentColor,
 }
 
-func isPropertyInList(tag string, list []string) bool {
+func isPropertyInList(tag PropertyName, list []PropertyName) bool {
 	for _, prop := range list {
 		if prop == tag {
 			return true
@@ -30,14 +31,11 @@ func isPropertyInList(tag string, list []string) bool {
 	return false
 }
 
-var angleProperties = []string{
-	Rotate,
-	SkewX,
-	SkewY,
+var angleProperties = []PropertyName{
 	From,
 }
 
-var boolProperties = []string{
+var boolProperties = []PropertyName{
 	Disabled,
 	Focusable,
 	Inset,
@@ -64,9 +62,11 @@ var boolProperties = []string{
 	Repeating,
 	UserSelect,
 	ColumnSpanAll,
+	MoveToFrontAnimation,
+	HideSummaryMarker,
 }
 
-var intProperties = []string{
+var intProperties = []PropertyName{
 	ZIndex,
 	TabSize,
 	HeadHeight,
@@ -76,16 +76,12 @@ var intProperties = []string{
 	ColumnCount,
 	Order,
 	TabIndex,
+	MaxLength,
+	NumberPickerPrecision,
 }
 
-var floatProperties = map[string]struct{ min, max float64 }{
+var floatProperties = map[PropertyName]struct{ min, max float64 }{
 	Opacity:           {min: 0, max: 1},
-	ScaleX:            {min: -math.MaxFloat64, max: math.MaxFloat64},
-	ScaleY:            {min: -math.MaxFloat64, max: math.MaxFloat64},
-	ScaleZ:            {min: -math.MaxFloat64, max: math.MaxFloat64},
-	RotateX:           {min: 0, max: 1},
-	RotateY:           {min: 0, max: 1},
-	RotateZ:           {min: 0, max: 1},
 	NumberPickerMax:   {min: -math.MaxFloat64, max: math.MaxFloat64},
 	NumberPickerMin:   {min: -math.MaxFloat64, max: math.MaxFloat64},
 	NumberPickerStep:  {min: -math.MaxFloat64, max: math.MaxFloat64},
@@ -94,88 +90,88 @@ var floatProperties = map[string]struct{ min, max float64 }{
 	ProgressBarValue:  {min: 0, max: math.MaxFloat64},
 	VideoWidth:        {min: 0, max: 10000},
 	VideoHeight:       {min: 0, max: 10000},
+	PushDuration:      {min: 0, max: math.MaxFloat64},
 }
 
-var sizeProperties = map[string]string{
-	Width:              Width,
-	Height:             Height,
-	MinWidth:           MinWidth,
-	MinHeight:          MinHeight,
-	MaxWidth:           MaxWidth,
-	MaxHeight:          MaxHeight,
-	Left:               Left,
-	Right:              Right,
-	Top:                Top,
-	Bottom:             Bottom,
+var sizeProperties = map[PropertyName]string{
+	Width:              string(Width),
+	Height:             string(Height),
+	MinWidth:           string(MinWidth),
+	MinHeight:          string(MinHeight),
+	MaxWidth:           string(MaxWidth),
+	MaxHeight:          string(MaxHeight),
+	Left:               string(Left),
+	Right:              string(Right),
+	Top:                string(Top),
+	Bottom:             string(Bottom),
 	TextSize:           "font-size",
-	TextIndent:         TextIndent,
-	LetterSpacing:      LetterSpacing,
-	WordSpacing:        WordSpacing,
-	LineHeight:         LineHeight,
+	TextIndent:         string(TextIndent),
+	LetterSpacing:      string(LetterSpacing),
+	WordSpacing:        string(WordSpacing),
+	LineHeight:         string(LineHeight),
 	TextLineThickness:  "text-decoration-thickness",
 	ListRowGap:         "row-gap",
 	ListColumnGap:      "column-gap",
-	GridRowGap:         GridRowGap,
-	GridColumnGap:      GridColumnGap,
-	ColumnWidth:        ColumnWidth,
-	ColumnGap:          ColumnGap,
-	Gap:                Gap,
-	Margin:             Margin,
-	MarginLeft:         MarginLeft,
-	MarginRight:        MarginRight,
-	MarginTop:          MarginTop,
-	MarginBottom:       MarginBottom,
-	Padding:            Padding,
-	PaddingLeft:        PaddingLeft,
-	PaddingRight:       PaddingRight,
-	PaddingTop:         PaddingTop,
-	PaddingBottom:      PaddingBottom,
-	BorderWidth:        BorderWidth,
-	BorderLeftWidth:    BorderLeftWidth,
-	BorderRightWidth:   BorderRightWidth,
-	BorderTopWidth:     BorderTopWidth,
-	BorderBottomWidth:  BorderBottomWidth,
-	OutlineWidth:       OutlineWidth,
-	OutlineOffset:      OutlineOffset,
-	XOffset:            XOffset,
-	YOffset:            YOffset,
-	BlurRadius:         BlurRadius,
-	SpreadRadius:       SpreadRadius,
-	Perspective:        Perspective,
-	PerspectiveOriginX: PerspectiveOriginX,
-	PerspectiveOriginY: PerspectiveOriginY,
-	OriginX:            OriginX,
-	OriginY:            OriginY,
-	OriginZ:            OriginZ,
-	TranslateX:         TranslateX,
-	TranslateY:         TranslateY,
-	TranslateZ:         TranslateZ,
-	Radius:             Radius,
-	RadiusX:            RadiusX,
-	RadiusY:            RadiusY,
-	RadiusTopLeft:      RadiusTopLeft,
-	RadiusTopLeftX:     RadiusTopLeftX,
-	RadiusTopLeftY:     RadiusTopLeftY,
-	RadiusTopRight:     RadiusTopRight,
-	RadiusTopRightX:    RadiusTopRightX,
-	RadiusTopRightY:    RadiusTopRightY,
-	RadiusBottomLeft:   RadiusBottomLeft,
-	RadiusBottomLeftX:  RadiusBottomLeftX,
-	RadiusBottomLeftY:  RadiusBottomLeftY,
-	RadiusBottomRight:  RadiusBottomRight,
-	RadiusBottomRightX: RadiusBottomRightX,
-	RadiusBottomRightY: RadiusBottomRightY,
-	ItemWidth:          ItemWidth,
-	ItemHeight:         ItemHeight,
-	CenterX:            CenterX,
-	CenterY:            CenterX,
+	GridRowGap:         string(GridRowGap),
+	GridColumnGap:      string(GridColumnGap),
+	ColumnWidth:        string(ColumnWidth),
+	ColumnGap:          string(ColumnGap),
+	Gap:                string(Gap),
+	Margin:             string(Margin),
+	MarginLeft:         string(MarginLeft),
+	MarginRight:        string(MarginRight),
+	MarginTop:          string(MarginTop),
+	MarginBottom:       string(MarginBottom),
+	Padding:            string(Padding),
+	PaddingLeft:        string(PaddingLeft),
+	PaddingRight:       string(PaddingRight),
+	PaddingTop:         string(PaddingTop),
+	PaddingBottom:      string(PaddingBottom),
+	BorderWidth:        string(BorderWidth),
+	BorderLeftWidth:    string(BorderLeftWidth),
+	BorderRightWidth:   string(BorderRightWidth),
+	BorderTopWidth:     string(BorderTopWidth),
+	BorderBottomWidth:  string(BorderBottomWidth),
+	OutlineWidth:       string(OutlineWidth),
+	OutlineOffset:      string(OutlineOffset),
+	XOffset:            string(XOffset),
+	YOffset:            string(YOffset),
+	BlurRadius:         string(BlurRadius),
+	SpreadRadius:       string(SpreadRadius),
+	Perspective:        string(Perspective),
+	PerspectiveOriginX: string(PerspectiveOriginX),
+	PerspectiveOriginY: string(PerspectiveOriginY),
+	TransformOriginX:   string(TransformOriginX),
+	TransformOriginY:   string(TransformOriginY),
+	TransformOriginZ:   string(TransformOriginZ),
+	Radius:             string(Radius),
+	RadiusX:            string(RadiusX),
+	RadiusY:            string(RadiusY),
+	RadiusTopLeft:      string(RadiusTopLeft),
+	RadiusTopLeftX:     string(RadiusTopLeftX),
+	RadiusTopLeftY:     string(RadiusTopLeftY),
+	RadiusTopRight:     string(RadiusTopRight),
+	RadiusTopRightX:    string(RadiusTopRightX),
+	RadiusTopRightY:    string(RadiusTopRightY),
+	RadiusBottomLeft:   string(RadiusBottomLeft),
+	RadiusBottomLeftX:  string(RadiusBottomLeftX),
+	RadiusBottomLeftY:  string(RadiusBottomLeftY),
+	RadiusBottomRight:  string(RadiusBottomRight),
+	RadiusBottomRightX: string(RadiusBottomRightX),
+	RadiusBottomRightY: string(RadiusBottomRightY),
+	ItemWidth:          string(ItemWidth),
+	ItemHeight:         string(ItemHeight),
+	CenterX:            string(CenterX),
+	CenterY:            string(CenterX),
 }
 
-var enumProperties = map[string]struct {
+type enumPropertyData struct {
 	values    []string
 	cssTag    string
 	cssValues []string
-}{
+}
+
+var enumProperties = map[PropertyName]enumPropertyData{
 	Semantics: {
 		[]string{"default", "article", "section", "aside", "header", "main", "footer", "navigation", "figure", "figure-caption", "button", "p", "h1", "h2", "h3", "h4", "h5", "h6", "blockquote", "code"},
 		"",
@@ -188,17 +184,17 @@ var enumProperties = map[string]struct {
 	},
 	Overflow: {
 		[]string{"hidden", "visible", "scroll", "auto"},
-		Overflow,
+		string(Overflow),
 		[]string{"hidden", "visible", "scroll", "auto"},
 	},
 	TextAlign: {
 		[]string{"left", "right", "center", "justify"},
-		TextAlign,
+		string(TextAlign),
 		[]string{"left", "right", "center", "justify"},
 	},
 	TextTransform: {
 		[]string{"none", "capitalize", "lowercase", "uppercase"},
-		TextTransform,
+		string(TextTransform),
 		[]string{"none", "capitalize", "lowercase", "uppercase"},
 	},
 	TextWeight: {
@@ -208,27 +204,27 @@ var enumProperties = map[string]struct {
 	},
 	WhiteSpace: {
 		[]string{"normal", "nowrap", "pre", "pre-wrap", "pre-line", "break-spaces"},
-		WhiteSpace,
+		string(WhiteSpace),
 		[]string{"normal", "nowrap", "pre", "pre-wrap", "pre-line", "break-spaces"},
 	},
 	WordBreak: {
 		[]string{"normal", "break-all", "keep-all", "break-word"},
-		WordBreak,
+		string(WordBreak),
 		[]string{"normal", "break-all", "keep-all", "break-word"},
 	},
 	TextOverflow: {
 		[]string{"clip", "ellipsis"},
-		TextOverflow,
+		string(TextOverflow),
 		[]string{"clip", "ellipsis"},
 	},
 	TextWrap: {
 		[]string{"wrap", "nowrap", "balance"},
-		TextWrap,
+		string(TextWrap),
 		[]string{"wrap", "nowrap", "balance"},
 	},
 	WritingMode: {
 		[]string{"horizontal-top-to-bottom", "horizontal-bottom-to-top", "vertical-right-to-left", "vertical-left-to-right"},
-		WritingMode,
+		string(WritingMode),
 		[]string{"horizontal-tb", "horizontal-bt", "vertical-rl", "vertical-lr"},
 	},
 	TextDirection: {
@@ -248,7 +244,7 @@ var enumProperties = map[string]struct {
 	},
 	BorderStyle: {
 		[]string{"none", "solid", "dashed", "dotted", "double"},
-		BorderStyle,
+		string(BorderStyle),
 		[]string{"none", "solid", "dashed", "dotted", "double"},
 	},
 	TopStyle: {
@@ -273,7 +269,7 @@ var enumProperties = map[string]struct {
 	},
 	OutlineStyle: {
 		[]string{"none", "solid", "dashed", "dotted", "double"},
-		OutlineStyle,
+		string(OutlineStyle),
 		[]string{"none", "solid", "dashed", "dotted", "double"},
 	},
 	Tabs: {
@@ -348,7 +344,7 @@ var enumProperties = map[string]struct {
 	},
 	GridAutoFlow: {
 		[]string{"row", "column", "row-dense", "column-dense"},
-		GridAutoFlow,
+		string(GridAutoFlow),
 		[]string{"row", "column", "row dense", "column dense"},
 	},
 	ImageVerticalAlign: {
@@ -388,7 +384,7 @@ var enumProperties = map[string]struct {
 	},
 	Cursor: {
 		[]string{"auto", "default", "none", "context-menu", "help", "pointer", "progress", "wait", "cell", "crosshair", "text", "vertical-text", "alias", "copy", "move", "no-drop", "not-allowed", "e-resize", "n-resize", "ne-resize", "nw-resize", "s-resize", "se-resize", "sw-resize", "w-resize", "ew-resize", "ns-resize", "nesw-resize", "nwse-resize", "col-resize", "row-resize", "all-scroll", "zoom-in", "zoom-out", "grab", "grabbing"},
-		Cursor,
+		string(Cursor),
 		[]string{"auto", "default", "none", "context-menu", "help", "pointer", "progress", "wait", "cell", "crosshair", "text", "vertical-text", "alias", "copy", "move", "no-drop", "not-allowed", "e-resize", "n-resize", "ne-resize", "nw-resize", "s-resize", "se-resize", "sw-resize", "w-resize", "ew-resize", "ns-resize", "nesw-resize", "nwse-resize", "col-resize", "row-resize", "all-scroll", "zoom-in", "zoom-out", "grab", "grabbing"},
 	},
 	Fit: {
@@ -416,6 +412,21 @@ var enumProperties = map[string]struct {
 		"background-clip",
 		[]string{"border-box", "padding-box", "content-box"}, // "text"},
 	},
+	BackgroundOrigin: {
+		[]string{"border-box", "padding-box", "content-box"},
+		"background-origin",
+		[]string{"border-box", "padding-box", "content-box"},
+	},
+	MaskClip: {
+		[]string{"border-box", "padding-box", "content-box"},
+		"mask-clip",
+		[]string{"border-box", "padding-box", "content-box"},
+	},
+	MaskOrigin: {
+		[]string{"border-box", "padding-box", "content-box"},
+		"background-origin",
+		[]string{"border-box", "padding-box", "content-box"},
+	},
 	Direction: {
 		[]string{"to-top", "to-right-top", "to-right", "to-right-bottom", "to-bottom", "to-left-bottom", "to-left", "to-left-top"},
 		"",
@@ -468,27 +479,27 @@ var enumProperties = map[string]struct {
 	},
 	MixBlendMode: {
 		[]string{"normal", "multiply", "screen", "overlay", "darken", "lighten", "color-dodge", "color-burn", "hard-light", "soft-light", "difference", "exclusion", "hue", "saturation", "color", "luminosity"},
-		MixBlendMode,
+		string(MixBlendMode),
 		[]string{"normal", "multiply", "screen", "overlay", "darken", "lighten", "color-dodge", "color-burn", "hard-light", "soft-light", "difference", "exclusion", "hue", "saturation", "color", "luminosity"},
 	},
 	BackgroundBlendMode: {
 		[]string{"normal", "multiply", "screen", "overlay", "darken", "lighten", "color-dodge", "color-burn", "hard-light", "soft-light", "difference", "exclusion", "hue", "saturation", "color", "luminosity"},
-		BackgroundBlendMode,
+		string(BackgroundBlendMode),
 		[]string{"normal", "multiply", "screen", "overlay", "darken", "lighten", "color-dodge", "color-burn", "hard-light", "soft-light", "difference", "exclusion", "hue", "saturation", "color", "luminosity"},
 	},
 	ColumnFill: {
 		[]string{"balance", "auto"},
-		ColumnFill,
+		string(ColumnFill),
 		[]string{"balance", "auto"},
 	},
 }
 
-func notCompatibleType(tag string, value any) {
-	ErrorLogF(`"%T" type not compatible with "%s" property`, value, tag)
+func notCompatibleType(tag PropertyName, value any) {
+	ErrorLogF(`"%T" type not compatible with "%s" property`, value, string(tag))
 }
 
-func invalidPropertyValue(tag string, value any) {
-	ErrorLogF(`Invalid value "%v" of "%s" property`, value, tag)
+func invalidPropertyValue(tag PropertyName, value any) {
+	ErrorLogF(`Invalid value "%v" of "%s" property`, value, string(tag))
 }
 
 func isConstantName(text string) bool {
@@ -549,26 +560,48 @@ func isInt(value any) (int, bool) {
 	return n, true
 }
 
-func (properties *propertyList) setSimpleProperty(tag string, value any) bool {
+func setSimpleProperty(properties Properties, tag PropertyName, value any) bool {
 	if value == nil {
-		delete(properties.properties, tag)
+		properties.setRaw(tag, nil)
 		return true
 	} else if text, ok := value.(string); ok {
 		text = strings.Trim(text, " \t\n\r")
 		if text == "" {
-			delete(properties.properties, tag)
+			properties.setRaw(tag, nil)
 			return true
 		}
 		if isConstantName(text) {
-			properties.properties[tag] = text
+			properties.setRaw(tag, text)
 			return true
 		}
 	}
 	return false
 }
 
-func (properties *propertyList) setSizeProperty(tag string, value any) bool {
-	if !properties.setSimpleProperty(tag, value) {
+func setStringPropertyValue(properties Properties, tag PropertyName, text any) []PropertyName {
+	if text != "" {
+		properties.setRaw(tag, text)
+	} else if properties.getRaw(tag) != nil {
+		properties.setRaw(tag, nil)
+	} else {
+		return []PropertyName{}
+	}
+	return []PropertyName{tag}
+}
+
+func setArrayPropertyValue[T any](properties Properties, tag PropertyName, value []T) []PropertyName {
+	if len(value) > 0 {
+		properties.setRaw(tag, value)
+	} else if properties.getRaw(tag) != nil {
+		properties.setRaw(tag, nil)
+	} else {
+		return []PropertyName{}
+	}
+	return []PropertyName{tag}
+}
+
+func setSizeProperty(properties Properties, tag PropertyName, value any) []PropertyName {
+	if !setSimpleProperty(properties, tag, value) {
 		var size SizeUnit
 		switch value := value.(type) {
 		case string:
@@ -578,7 +611,7 @@ func (properties *propertyList) setSizeProperty(tag string, value any) bool {
 				size.Function = fn
 			} else if size, ok = StringToSizeUnit(value); !ok {
 				invalidPropertyValue(tag, value)
-				return false
+				return nil
 			}
 		case SizeUnit:
 			size = value
@@ -601,29 +634,29 @@ func (properties *propertyList) setSizeProperty(tag string, value any) bool {
 				size.Value = float64(n)
 			} else {
 				notCompatibleType(tag, value)
-				return false
+				return nil
 			}
 		}
 
 		if size.Type == Auto {
-			delete(properties.properties, tag)
+			properties.setRaw(tag, nil)
 		} else {
-			properties.properties[tag] = size
+			properties.setRaw(tag, size)
 		}
 	}
 
-	return true
+	return []PropertyName{tag}
 }
 
-func (properties *propertyList) setAngleProperty(tag string, value any) bool {
-	if !properties.setSimpleProperty(tag, value) {
+func setAngleProperty(properties Properties, tag PropertyName, value any) []PropertyName {
+	if !setSimpleProperty(properties, tag, value) {
 		var angle AngleUnit
 		switch value := value.(type) {
 		case string:
 			var ok bool
 			if angle, ok = StringToAngleUnit(value); !ok {
 				invalidPropertyValue(tag, value)
-				return false
+				return nil
 			}
 		case AngleUnit:
 			angle = value
@@ -639,24 +672,24 @@ func (properties *propertyList) setAngleProperty(tag string, value any) bool {
 				angle = Rad(float64(n))
 			} else {
 				notCompatibleType(tag, value)
-				return false
+				return nil
 			}
 		}
-		properties.properties[tag] = angle
+		properties.setRaw(tag, angle)
 	}
 
-	return true
+	return []PropertyName{tag}
 }
 
-func (properties *propertyList) setColorProperty(tag string, value any) bool {
-	if !properties.setSimpleProperty(tag, value) {
+func setColorProperty(properties Properties, tag PropertyName, value any) []PropertyName {
+	if !setSimpleProperty(properties, tag, value) {
 		var result Color
 		switch value := value.(type) {
 		case string:
 			var err error
 			if result, err = stringToColor(value); err != nil {
 				invalidPropertyValue(tag, value)
-				return false
+				return nil
 			}
 		case Color:
 			result = value
@@ -666,105 +699,101 @@ func (properties *propertyList) setColorProperty(tag string, value any) bool {
 				result = Color(color)
 			} else {
 				notCompatibleType(tag, value)
-				return false
+				return nil
 			}
 		}
 
-		if result == 0 {
-			delete(properties.properties, tag)
-		} else {
-			properties.properties[tag] = result
-		}
+		properties.setRaw(tag, result)
 	}
 
-	return true
+	return []PropertyName{tag}
 }
 
-func (properties *propertyList) setEnumProperty(tag string, value any, values []string) bool {
-	if !properties.setSimpleProperty(tag, value) {
+func setEnumProperty(properties Properties, tag PropertyName, value any, values []string) []PropertyName {
+	if !setSimpleProperty(properties, tag, value) {
 		var n int
 		if text, ok := value.(string); ok {
 			if n, ok = enumStringToInt(text, values, false); !ok {
 				invalidPropertyValue(tag, value)
-				return false
+				return nil
 			}
 		} else if i, ok := isInt(value); ok {
 			if i < 0 || i >= len(values) {
 				invalidPropertyValue(tag, value)
-				return false
+				return nil
 			}
 			n = i
 		} else {
 			notCompatibleType(tag, value)
-			return false
+			return nil
 		}
 
-		properties.properties[tag] = n
+		properties.setRaw(tag, n)
 	}
 
-	return true
+	return []PropertyName{tag}
 }
 
-func (properties *propertyList) setBoolProperty(tag string, value any) bool {
-	if !properties.setSimpleProperty(tag, value) {
+func setBoolProperty(properties Properties, tag PropertyName, value any) []PropertyName {
+	if !setSimpleProperty(properties, tag, value) {
 		if text, ok := value.(string); ok {
 			switch strings.ToLower(strings.Trim(text, " \t")) {
 			case "true", "yes", "on", "1":
-				properties.properties[tag] = true
+				properties.setRaw(tag, true)
 
 			case "false", "no", "off", "0":
-				properties.properties[tag] = false
+				properties.setRaw(tag, false)
 
 			default:
 				invalidPropertyValue(tag, value)
-				return false
+				return nil
 			}
 		} else if n, ok := isInt(value); ok {
 			switch n {
 			case 1:
-				properties.properties[tag] = true
+				properties.setRaw(tag, true)
 
 			case 0:
-				properties.properties[tag] = false
+				properties.setRaw(tag, false)
 
 			default:
 				invalidPropertyValue(tag, value)
-				return false
+				return nil
 			}
 		} else if b, ok := value.(bool); ok {
-			properties.properties[tag] = b
+			properties.setRaw(tag, b)
 		} else {
 			notCompatibleType(tag, value)
-			return false
+			return nil
 		}
 	}
 
-	return true
+	return []PropertyName{tag}
 }
 
-func (properties *propertyList) setIntProperty(tag string, value any) bool {
-	if !properties.setSimpleProperty(tag, value) {
+func setIntProperty(properties Properties, tag PropertyName, value any) []PropertyName {
+	if !setSimpleProperty(properties, tag, value) {
 		if text, ok := value.(string); ok {
 			n, err := strconv.Atoi(strings.Trim(text, " \t"))
 			if err != nil {
 				invalidPropertyValue(tag, value)
 				ErrorLog(err.Error())
-				return false
+				return nil
 			}
-			properties.properties[tag] = n
+			properties.setRaw(tag, n)
 		} else if n, ok := isInt(value); ok {
-			properties.properties[tag] = n
+			properties.setRaw(tag, n)
 		} else {
 			notCompatibleType(tag, value)
-			return false
+			return nil
 		}
 	}
 
-	return true
+	return []PropertyName{tag}
 }
 
-func (properties *propertyList) setFloatProperty(tag string, value any, min, max float64) bool {
-	if !properties.setSimpleProperty(tag, value) {
+func setFloatProperty(properties Properties, tag PropertyName, value any, min, max float64) []PropertyName {
+	if !setSimpleProperty(properties, tag, value) {
 		f := float64(0)
 		switch value := value.(type) {
 		case string:
@@ -772,14 +801,14 @@ func (properties *propertyList) setFloatProperty(tag string, value any, min, max
 			if f, err = strconv.ParseFloat(strings.Trim(value, " \t"), 64); err != nil {
 				invalidPropertyValue(tag, value)
 				ErrorLog(err.Error())
-				return false
+				return nil
 			}
 			if f < min || f > max {
 				ErrorLogF(`"%T" out of range of "%s" property`, value, tag)
-				return false
+				return nil
 			}
-			properties.properties[tag] = value
-			return true
+			properties.setRaw(tag, value)
+			return nil
 
 		case float32:
 			f = float64(value)
@@ -792,64 +821,84 @@ func (properties *propertyList) setFloatProperty(tag string, value any, min, max
 				f = float64(n)
 			} else {
 				notCompatibleType(tag, value)
-				return false
+				return nil
 			}
 		}
 
 		if f >= min && f <= max {
-			properties.properties[tag] = f
+			properties.setRaw(tag, f)
 		} else {
 			ErrorLogF(`"%T" out of range of "%s" property`, value, tag)
-			return false
+			return nil
 		}
 	}
 
-	return true
+	return []PropertyName{tag}
 }
 
-func (properties *propertyList) Set(tag string, value any) bool {
-	return properties.set(strings.ToLower(tag), value)
-}
-
-func (properties *propertyList) set(tag string, value any) bool {
-	if value == nil {
-		delete(properties.properties, tag)
-		return true
-	}
-
+func propertiesSet(properties Properties, tag PropertyName, value any) []PropertyName {
 	if _, ok := sizeProperties[tag]; ok {
-		return properties.setSizeProperty(tag, value)
+		return setSizeProperty(properties, tag, value)
 	}
 
 	if valuesData, ok := enumProperties[tag]; ok {
-		return properties.setEnumProperty(tag, value, valuesData.values)
+		return setEnumProperty(properties, tag, value, valuesData.values)
 	}
 
 	if limits, ok := floatProperties[tag]; ok {
-		return properties.setFloatProperty(tag, value, limits.min, limits.max)
+		return setFloatProperty(properties, tag, value, limits.min, limits.max)
 	}
 
 	if isPropertyInList(tag, colorProperties) {
-		return properties.setColorProperty(tag, value)
+		return setColorProperty(properties, tag, value)
 	}
 
 	if isPropertyInList(tag, angleProperties) {
-		return properties.setAngleProperty(tag, value)
+		return setAngleProperty(properties, tag, value)
 	}
 
 	if isPropertyInList(tag, boolProperties) {
-		return properties.setBoolProperty(tag, value)
+		return setBoolProperty(properties, tag, value)
 	}
 
 	if isPropertyInList(tag, intProperties) {
-		return properties.setIntProperty(tag, value)
+		return setIntProperty(properties, tag, value)
 	}
 
 	if text, ok := value.(string); ok {
-		properties.properties[tag] = text
-		return true
+		properties.setRaw(tag, text)
+		return []PropertyName{tag}
 	}
 
 	notCompatibleType(tag, value)
+	return nil
+}
+
+/*
+func (properties *propertyList) Set(tag PropertyName, value any) bool {
+	tag = properties.normalize(tag)
+	if value == nil {
+		properties.remove(properties, tag)
+		return true
+	}
+
+	return properties.set(properties, tag, value) != nil
+}
+*/
+
+func (data *dataProperty) Set(tag PropertyName, value any) bool {
+	if value == nil {
+		data.Remove(tag)
+		return true
+	}
+
+	tag = data.normalize(tag)
+	for _, supported := range data.supportedProperties {
+		if tag == supported {
+			return data.set(data, tag, value) != nil
+		}
+	}
+
+	ErrorLogF(`"%s" property is not supported`, string(tag))
 	return false
 }

propertyValues.go

@@ -1,5 +1,6 @@
 package rui
 
+// Constants for various specific properties of a views
 const (
 	// Visible - default value of the view Visibility property: View is visible
 	Visible = 0
@@ -148,9 +149,9 @@ const (
 	WhiteSpacePreLine = 4
 
 	// WhiteSpaceBreakSpaces - the behavior is identical to that of WhiteSpacePreWrap, except that:
-	// * Any sequence of preserved white space always takes up space, including at the end of the line.
-	// * A line breaking opportunity exists after every preserved white space character, including between white space characters.
-	// * Such preserved spaces take up space and do not hang, and thus affect the box’s intrinsic sizes (min-content size and max-content size).
+	//   - Any sequence of preserved white space always takes up space, including at the end of the line.
+	//   - A line breaking opportunity exists after every preserved white space character, including between white space characters.
+	//   - Such preserved spaces take up space and do not hang, and thus affect the box’s intrinsic sizes (min-content size and max-content size).
 	WhiteSpaceBreakSpaces = 5
 
 	// WordBreakNormal - use the default line break rule.

range.go

@@ -0,0 +1,75 @@
+package rui
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+)
+
+// Range defines range limits. The First and Last value are included in the range
+type Range struct {
+	First, Last int
+}
+
+// String returns a string representation of the Range struct
+func (r Range) String() string {
+	if r.First == r.Last {
+		return fmt.Sprintf("%d", r.First)
+	}
+	return fmt.Sprintf("%d:%d", r.First, r.Last)
+}
+
+func (r *Range) setValue(value string) bool {
+	var err error
+	if strings.Contains(value, ":") {
+		values := strings.Split(value, ":")
+		if len(values) != 2 {
+			ErrorLog("Invalid range value: " + value)
+			return false
+		}
+		if r.First, err = strconv.Atoi(strings.Trim(values[0], " \t\n\r")); err != nil {
+			ErrorLog(`Invalid first range value "` + value + `" (` + err.Error() + ")")
+			return false
+		}
+		if r.Last, err = strconv.Atoi(strings.Trim(values[1], " \t\n\r")); err != nil {
+			ErrorLog(`Invalid last range value "` + value + `" (` + err.Error() + ")")
+			return false
+		}
+		return true
+	}
+
+	if r.First, err = strconv.Atoi(value); err != nil {
+		ErrorLog(`Invalid range value "` + value + `" (` + err.Error() + ")")
+		return false
+	}
+	r.Last = r.First
+	return true
+}
+
+func setRangeProperty(properties Properties, tag PropertyName, value any) []PropertyName {
+	switch value := value.(type) {
+	case string:
+		if setSimpleProperty(properties, tag, value) {
+			return []PropertyName{tag}
+		}
+
+		var r Range
+		if !r.setValue(value) {
+			invalidPropertyValue(tag, value)
+			return nil
+		}
+		properties.setRaw(tag, r)
+
+	case Range:
+		properties.setRaw(tag, value)
+
+	default:
+		if n, ok := isInt(value); ok {
+			properties.setRaw(tag, Range{First: n, Last: n})
+		} else {
+			notCompatibleType(tag, value)
+			return nil
+		}
+	}
+	return []PropertyName{tag}
+}

resizable.go

@@ -6,16 +6,38 @@ import (
 	"strings"
 )
 
+// Constants for [Resizable] specific properties and events
 const (
-	// Side is the constant for the "side" property tag.
-	// The "side" int property determines which side of the container is used to resize.
-	// The value of property is or-combination of TopSide (1), RightSide (2), BottomSide (4), and LeftSide (8)
-	Side = "side"
+	// Side is the constant for "side" property tag.
+	//
+	// Used by Resizable.
+	// Determines which side of the container is used to resize. The value of property is an or-combination of values listed.
+	// Default value is "all".
+	//
+	// Supported types: int, string.
+	//
+	// Values:
+	//   - 1 (TopSide) or "top" - Top frame side.
+	//   - 2 (RightSide) or "right" - Right frame side.
+	//   - 4 (BottomSide) or "bottom" - Bottom frame side.
+	//   - 8 (LeftSide) or "left" - Left frame side.
+	//   - 15 (AllSides) or "all" - All frame sides.
+	Side PropertyName = "side"
 
-	// ResizeBorderWidth is the constant for the "resize-border-width" property tag.
-	// The "ResizeBorderWidth" SizeUnit property determines the width of the resizing border
-	ResizeBorderWidth = "resize-border-width"
+	// ResizeBorderWidth is the constant for "resize-border-width" property tag.
+	//
+	// Used by Resizable.
+	// Specifies the width of the resizing border.
+	//
+	// Supported types: SizeUnit, SizeFunc, string, float, int.
+	//
+	// Internal type is SizeUnit, other types converted to it during assignment.
+	// See SizeUnit description for more details.
+	ResizeBorderWidth PropertyName = "resize-border-width"
+)
 
+// Constants for values of [Resizable] "side" property. These constants can be ORed if needed.
+const (
 	// TopSide is value of the "side" property: the top side is used to resize
 	TopSide = 1
 
@@ -32,7 +54,7 @@ const (
 	AllSides = TopSide | RightSide | BottomSide | LeftSide
 )
 
-// Resizable - grid-container of View
+// Resizable represents a Resizable view
 type Resizable interface {
 	View
 	ParentView
@@ -40,7 +62,6 @@ type Resizable interface {
 
 type resizableData struct {
 	viewData
-	content []View
 }
 
 // NewResizable create new Resizable object and return it
@@ -52,97 +73,40 @@ func NewResizable(session Session, params Params) Resizable {
 }
 
 func newResizable(session Session) View {
-	return NewResizable(session, nil)
+	return new(resizableData)
 }
 
 func (resizable *resizableData) init(session Session) {
 	resizable.viewData.init(session)
 	resizable.tag = "Resizable"
 	resizable.systemClass = "ruiGridLayout"
-	resizable.content = []View{}
-}
-
-func (resizable *resizableData) String() string {
-	return getViewString(resizable, nil)
+	resizable.set = resizable.setFunc
+	resizable.changed = resizable.propertyChanged
 }
 
 func (resizable *resizableData) Views() []View {
-	return resizable.content
+	if view := resizable.content(); view != nil {
+		return []View{view}
+	}
+	return []View{}
 }
 
-func (resizable *resizableData) Remove(tag string) {
-	resizable.remove(strings.ToLower(tag))
+func (resizable *resizableData) content() View {
+	if value := resizable.getRaw(Content); value != nil {
+		if content, ok := value.(View); ok {
+			return content
+		}
+	}
+	return nil
 }
 
-func (resizable *resizableData) remove(tag string) {
+func (resizable *resizableData) setFunc(tag PropertyName, value any) []PropertyName {
 	switch tag {
 	case Side:
-		oldSide := resizable.getSide()
-		delete(resizable.properties, Side)
-		if oldSide != resizable.getSide() {
-			if resizable.created {
-				updateInnerHTML(resizable.htmlID(), resizable.Session())
-				resizable.updateResizeBorderWidth()
-			}
-			resizable.propertyChangedEvent(tag)
-		}
+		return resizableSetSide(resizable, value)
 
 	case ResizeBorderWidth:
-		w := resizable.resizeBorderWidth()
-		delete(resizable.properties, ResizeBorderWidth)
-		if !w.Equal(resizable.resizeBorderWidth()) {
-			resizable.updateResizeBorderWidth()
-			resizable.propertyChangedEvent(tag)
-		}
-
-	case Content:
-		if len(resizable.content) > 0 {
-			resizable.content = []View{}
-			if resizable.created {
-				updateInnerHTML(resizable.htmlID(), resizable.Session())
-			}
-			resizable.propertyChangedEvent(tag)
-		}
-
-	default:
-		resizable.viewData.remove(tag)
-	}
-}
-
-func (resizable *resizableData) Set(tag string, value any) bool {
-	return resizable.set(strings.ToLower(tag), value)
-}
-
-func (resizable *resizableData) set(tag string, value any) bool {
-	if value == nil {
-		resizable.remove(tag)
-		return true
-	}
-
-	switch tag {
-	case Side:
-		oldSide := resizable.getSide()
-		if !resizable.setSide(value) {
-			notCompatibleType(tag, value)
-			return false
-		}
-		if oldSide != resizable.getSide() {
-			if resizable.created {
-				updateInnerHTML(resizable.htmlID(), resizable.Session())
-				resizable.updateResizeBorderWidth()
-			}
-			resizable.propertyChangedEvent(tag)
-		}
-		return true
-
-	case ResizeBorderWidth:
-		w := resizable.resizeBorderWidth()
-		ok := resizable.setSizeProperty(tag, value)
-		if ok && !w.Equal(resizable.resizeBorderWidth()) {
-			resizable.updateResizeBorderWidth()
-			resizable.propertyChangedEvent(tag)
-		}
-		return ok
+		return setSizeProperty(resizable, tag, value)
 
 	case Content:
 		var newContent View = nil
@@ -154,45 +118,54 @@ func (resizable *resizableData) set(tag string, value any) bool {
 			newContent = value
 
 		case DataObject:
-			if view := CreateViewFromObject(resizable.Session(), value); view != nil {
-				newContent = view
-			} else {
-				return false
+			if newContent = CreateViewFromObject(resizable.Session(), value); newContent == nil {
+				return nil
 			}
 
 		default:
 			notCompatibleType(tag, value)
-			return false
+			return nil
 		}
 
-		if len(resizable.content) == 0 {
-			resizable.content = []View{newContent}
-		} else {
-			resizable.content[0] = newContent
-		}
-		if resizable.created {
-			updateInnerHTML(resizable.htmlID(), resizable.Session())
-		}
-		resizable.propertyChangedEvent(tag)
-		return true
+		resizable.setRaw(Content, newContent)
+		return []PropertyName{}
 
 	case CellWidth, CellHeight, GridRowGap, GridColumnGap, CellVerticalAlign, CellHorizontalAlign:
-		ErrorLogF(`Not supported "%s" property`, tag)
-		return false
+		ErrorLogF(`Not supported "%s" property`, string(tag))
+		return nil
 	}
 
-	return resizable.viewData.set(tag, value)
+	return resizable.viewData.setFunc(tag, value)
 }
 
-func (resizable *resizableData) Get(tag string) any {
-	return resizable.get(strings.ToLower(tag))
+func (resizable *resizableData) propertyChanged(tag PropertyName) {
+	switch tag {
+	case Side:
+		updateInnerHTML(resizable.htmlID(), resizable.Session())
+		fallthrough
+
+	case ResizeBorderWidth:
+		htmlID := resizable.htmlID()
+		session := resizable.Session()
+		column, row := resizableCellSizeCSS(resizable)
+
+		session.updateCSSProperty(htmlID, "grid-template-columns", column)
+		session.updateCSSProperty(htmlID, "grid-template-rows", row)
+
+	case Content:
+		updateInnerHTML(resizable.htmlID(), resizable.Session())
+
+	default:
+		resizable.viewData.propertyChanged(tag)
+	}
+
 }
 
-func (resizable *resizableData) getSide() int {
-	if value := resizable.getRaw(Side); value != nil {
+func resizableSide(view View) int {
+	if value := view.getRaw(Side); value != nil {
 		switch value := value.(type) {
 		case string:
-			if value, ok := resizable.session.resolveConstants(value); ok {
+			if value, ok := view.Session().resolveConstants(value); ok {
 				validValues := map[string]int{
 					"top":    TopSide,
 					"right":  RightSide,
@@ -236,15 +209,15 @@ func (resizable *resizableData) getSide() int {
 	return AllSides
 }
 
-func (resizable *resizableData) setSide(value any) bool {
+func resizableSetSide(properties Properties, value any) []PropertyName {
 	switch value := value.(type) {
 	case string:
 		if n, err := strconv.Atoi(value); err == nil {
 			if n >= 1 && n <= AllSides {
-				resizable.properties[Side] = n
-				return true
+				properties.setRaw(Side, n)
+				return []PropertyName{Side}
 			}
-			return false
+			return nil
 		}
 		validValues := map[string]int{
 			"top":    TopSide,
@@ -265,13 +238,13 @@ func (resizable *resizableData) setSide(value any) bool {
 					hasConst = true
 				} else if n, err := strconv.Atoi(val); err == nil {
 					if n < 1 || n > AllSides {
-						return false
+						return nil
 					}
 					sides |= n
 				} else if n, ok := validValues[val]; ok {
 					sides |= n
 				} else {
-					return false
+					return nil
 				}
 			}
 
@@ -280,69 +253,58 @@ func (resizable *resizableData) setSide(value any) bool {
 				for i := 1; i < len(values); i++ {
 					value += "|" + values[i]
 				}
-				resizable.properties[Side] = value
-				return true
+				properties.setRaw(Side, value)
+				return []PropertyName{Side}
 			}
 
 			if sides >= 1 && sides <= AllSides {
-				resizable.properties[Side] = sides
-				return true
+				properties.setRaw(Side, sides)
+				return []PropertyName{Side}
 			}
 
 		} else if value[0] == '@' {
-			resizable.properties[Side] = value
-			return true
+			properties.setRaw(Side, value)
+			return []PropertyName{Side}
 		} else if n, ok := validValues[value]; ok {
-			resizable.properties[Side] = n
-			return true
+			properties.setRaw(Side, n)
+			return []PropertyName{Side}
 		}
 
 	case int:
 		if value >= 1 && value <= AllSides {
-			resizable.properties[Side] = value
-			return true
+			properties.setRaw(Side, value)
+			return []PropertyName{Side}
 		} else {
 			ErrorLogF(`Invalid value %d of "side" property`, value)
-			return false
+			return nil
 		}
 
 	default:
 		if n, ok := isInt(value); ok {
 			if n >= 1 && n <= AllSides {
-				resizable.properties[Side] = n
-				return true
+				properties.setRaw(Side, n)
+				return []PropertyName{Side}
 			} else {
 				ErrorLogF(`Invalid value %d of "side" property`, n)
-				return false
+				return nil
 			}
 		}
 	}
 
-	return false
+	return nil
 }
 
-func (resizable *resizableData) resizeBorderWidth() SizeUnit {
-	result, _ := sizeProperty(resizable, ResizeBorderWidth, resizable.Session())
+func resizableBorderWidth(view View) SizeUnit {
+	result, _ := sizeProperty(view, ResizeBorderWidth, view.Session())
 	if result.Type == Auto || result.Value == 0 {
 		return Px(4)
 	}
 	return result
 }
 
-func (resizable *resizableData) updateResizeBorderWidth() {
-	if resizable.created {
-		htmlID := resizable.htmlID()
-		session := resizable.Session()
-		column, row := resizable.cellSizeCSS()
-
-		session.updateCSSProperty(htmlID, "grid-template-columns", column)
-		session.updateCSSProperty(htmlID, "grid-template-rows", row)
-	}
-}
-
-func (resizable *resizableData) cellSizeCSS() (string, string) {
-	w := resizable.resizeBorderWidth().cssString("4px", resizable.Session())
-	side := resizable.getSide()
+func resizableCellSizeCSS(view View) (string, string) {
+	w := resizableBorderWidth(view).cssString("4px", view.Session())
+	side := resizableSide(view)
 	column := "1fr"
 	row := "1fr"
 
@@ -370,7 +332,7 @@ func (resizable *resizableData) cellSizeCSS() (string, string) {
 }
 
 func (resizable *resizableData) cssStyle(self View, builder cssBuilder) {
-	column, row := resizable.cellSizeCSS()
+	column, row := resizableCellSizeCSS(resizable)
 
 	builder.add("grid-template-columns", column)
 	builder.add("grid-template-rows", row)
@@ -380,12 +342,12 @@ func (resizable *resizableData) cssStyle(self View, builder cssBuilder) {
 
 func (resizable *resizableData) htmlSubviews(self View, buffer *strings.Builder) {
 
-	side := resizable.getSide()
+	side := resizableSide(resizable)
 	left := 1
 	top := 1
 	leftSide := (side & LeftSide) != 0
 	rightSide := (side & RightSide) != 0
-	w := resizable.resizeBorderWidth().cssString("4px", resizable.Session())
+	w := resizableBorderWidth(resizable).cssString("4px", resizable.Session())
 
 	if leftSide {
 		left = 2
@@ -462,14 +424,13 @@ func (resizable *resizableData) htmlSubviews(self View, buffer *strings.Builder)
 		}
 	}
 
-	if len(resizable.content) > 0 {
-		view := resizable.content[0]
+	if view := resizable.content(); view != nil {
 		view.addToCSSStyle(map[string]string{
 			"grid-column-start": strconv.Itoa(left),
 			"grid-column-end":   strconv.Itoa(left + 1),
 			"grid-row-start":    strconv.Itoa(top),
 			"grid-row-end":      strconv.Itoa(top + 1),
 		})
-		viewHTML(view, buffer)
+		viewHTML(view, buffer, "")
 	}
 }

resizeEvent.go

@@ -1,15 +1,24 @@
 package rui
 
 // ResizeEvent is the constant for "resize-event" property tag.
-// The "resize-event" is fired when the view changes its size.
-// The main listener format:
 //
-//	func(View, Frame).
+// Used by View.
+// Is fired when the view changes its size.
 //
-// The additional listener formats:
+// General listener format:
 //
-//	func(Frame), func(View), and func().
-const ResizeEvent = "resize-event"
+//	func(view rui.View, frame rui.Frame)
+//
+// where:
+//   - view - Interface of a view which generated this event,
+//   - frame - New offset and size of the view's visible area.
+//
+// Allowed listener formats:
+//
+//	func(frame rui.Frame)
+//	func(view rui.View)
+//	func()
+const ResizeEvent PropertyName = "resize-event"
 
 func (view *viewData) onResize(self View, x, y, width, height float64) {
 	view.frame.Left = x
@@ -24,21 +33,20 @@ func (view *viewData) onResize(self View, x, y, width, height float64) {
 func (view *viewData) onItemResize(self View, index string, x, y, width, height float64) {
 }
 
-func (view *viewData) setFrameListener(tag string, value any) bool {
-	listeners, ok := valueToEventListeners[View, Frame](value)
-	if !ok {
-		notCompatibleType(tag, value)
-		return false
+/*
+func setFrameListener(properties Properties, tag PropertyName, value any) bool {
+	if listeners, ok := valueToOneArgEventListeners[View, Frame](value); ok {
+		if len(listeners) == 0 {
+			properties.setRaw(tag, nil)
+		} else {
+			properties.setRaw(tag, listeners)
+		}
+		return true
 	}
-
-	if listeners == nil {
-		delete(view.properties, tag)
-	} else {
-		view.properties[tag] = listeners
-	}
-	view.propertyChangedEvent(tag)
-	return true
+	notCompatibleType(tag, value)
+	return false
 }
+*/
 
 func (view *viewData) setNoResizeEvent() {
 	view.noResizeEvent = true
@@ -67,9 +75,7 @@ func (view *viewData) Frame() Frame {
 // GetViewFrame returns the size and location of view's viewport.
 // If the second argument (subviewID) is not specified or it is "" then the value of the first argument (view) is returned
 func GetViewFrame(view View, subviewID ...string) Frame {
-	if len(subviewID) > 0 && subviewID[0] != "" {
-		view = ViewByID(view, subviewID[0])
-	}
+	view = getSubview(view, subviewID)
 	if view == nil {
 		return Frame{}
 	}
@@ -79,5 +85,5 @@ func GetViewFrame(view View, subviewID ...string) Frame {
 // GetResizeListeners returns the list of "resize-event" listeners. If there are no listeners then the empty list is returned
 // If the second argument (subviewID) is not specified or it is "" then the listeners list of the first argument (view) is returned
 func GetResizeListeners(view View, subviewID ...string) []func(View, Frame) {
-	return getEventListeners[View, Frame](view, subviewID, ResizeEvent)
+	return getOneArgEventListeners[View, Frame](view, subviewID, ResizeEvent)
 }

resources.go

@@ -3,6 +3,7 @@ package rui
 import (
 	"embed"
 	"io"
+	"io/fs"
 	"net/http"
 	"os"
 	"path/filepath"
@@ -44,6 +45,7 @@ var resources = resourceManager{
 	imageSrcSets: map[string][]scaledImage{},
 }
 
+// AddEmbedResources adds embedded resources to the list of application resources
 func AddEmbedResources(fs *embed.FS) {
 	resources.embedFS = append(resources.embedFS, fs)
 	rootDirs := resources.embedRootDirs(fs)
@@ -329,7 +331,7 @@ func ReadRawResource(filename string) []byte {
 		rootDirs := resources.embedRootDirs(fs)
 		for _, dir := range rootDirs {
 			switch dir {
-			case imageDir, themeDir, viewDir:
+			case imageDir, themeDir, viewDir, stringsDir:
 				// do nothing
 
 			case rawDir:
@@ -361,6 +363,44 @@ func ReadRawResource(filename string) []byte {
 	return nil
 }
 
+// OpenRawResource returns the contents of the raw resource with the specified name
+func OpenRawResource(filename string) fs.File {
+	for _, fs := range resources.embedFS {
+		rootDirs := resources.embedRootDirs(fs)
+		for _, dir := range rootDirs {
+			switch dir {
+			case imageDir, themeDir, viewDir, stringsDir:
+				// do nothing
+
+			case rawDir:
+				if file, err := fs.Open(dir + "/" + filename); err == nil {
+					return file
+				}
+
+			default:
+				if file, err := fs.Open(dir + "/" + rawDir + "/" + filename); err == nil {
+					return file
+				}
+			}
+		}
+	}
+
+	if resources.path != "" {
+		if file, err := os.Open(resources.path + rawDir + "/" + filename); err == nil {
+			return file
+		}
+	}
+
+	if exe, err := os.Executable(); err == nil {
+		if file, err := os.Open(filepath.Dir(exe) + "/resources/" + rawDir + "/" + filename); err == nil {
+			return file
+		}
+	}
+
+	ErrorLogF(`The "%s" raw file don't found`, filename)
+	return nil
+}
+
 // AllRawResources returns the list of all raw resouces
 func AllRawResources() []string {
 	result := []string{}
@@ -418,6 +458,7 @@ func AllImageResources() []string {
 	return result
 }
 
+// AddTheme adds theme to application
 func AddTheme(theme Theme) {
 	if theme != nil {
 		name := theme.Name()

scrollEvent.go

@@ -1,15 +1,24 @@
 package rui
 
 // ScrollEvent is the constant for "scroll-event" property tag.
-// The "scroll-event" is fired when the content of the view is scrolled.
-// The main listener format:
 //
-//	func(View, Frame).
+// Used by View.
+// Is fired when the content of the view is scrolled.
 //
-// The additional listener formats:
+// General listener format:
 //
-//	func(Frame), func(View), and func().
-const ScrollEvent = "scroll-event"
+//	func(view rui.View, frame rui.Frame)
+//
+// where:
+//   - view - Interface of a view which generated this event,
+//   - frame - New offset and size of the view's visible area.
+//
+// Allowed listener formats:
+//
+//	func(frame rui.Frame)
+//	func(view rui.View)
+//	func()
+const ScrollEvent PropertyName = "scroll-event"
 
 func (view *viewData) onScroll(self View, x, y, width, height float64) {
 	view.scroll.Left = x
@@ -35,9 +44,7 @@ func (view *viewData) setScroll(x, y, width, height float64) {
 // GetViewScroll returns ...
 // If the second argument (subviewID) is not specified or it is "" then a value of the first argument (view) is returned
 func GetViewScroll(view View, subviewID ...string) Frame {
-	if len(subviewID) > 0 && subviewID[0] != "" {
-		view = ViewByID(view, subviewID[0])
-	}
+	view = getSubview(view, subviewID)
 	if view == nil {
 		return Frame{}
 	}
@@ -47,7 +54,7 @@ func GetViewScroll(view View, subviewID ...string) Frame {
 // GetScrollListeners returns the list of "scroll-event" listeners. If there are no listeners then the empty list is returned
 // If the second argument (subviewID) is not specified or it is "" then the listeners list of the first argument (view) is returned
 func GetScrollListeners(view View, subviewID ...string) []func(View, Frame) {
-	return getEventListeners[View, Frame](view, subviewID, ResizeEvent)
+	return getOneArgEventListeners[View, Frame](view, subviewID, ResizeEvent)
 }
 
 // ScrollTo scrolls the view's content to the given position.
@@ -64,10 +71,7 @@ func ScrollViewTo(view View, subviewID string, x, y float64) {
 // ScrollViewToEnd scrolls the view's content to the start of view.
 // If the second argument (subviewID) is not specified or it is "" then the first argument (view) is used
 func ScrollViewToStart(view View, subviewID ...string) {
-	if len(subviewID) > 0 && subviewID[0] != "" {
-		view = ViewByID(view, subviewID[0])
-	}
-	if view != nil {
+	if view = getSubview(view, subviewID); view != nil {
 		view.Session().callFunc("scrollToStart", view.htmlID())
 	}
 }
@@ -75,10 +79,7 @@ func ScrollViewToStart(view View, subviewID ...string) {
 // ScrollViewToEnd scrolls the view's content to the end of view.
 // If the second argument (subviewID) is not specified or it is "" then the first argument (view) is used
 func ScrollViewToEnd(view View, subviewID ...string) {
-	if len(subviewID) > 0 && subviewID[0] != "" {
-		view = ViewByID(view, subviewID[0])
-	}
-	if view != nil {
+	if view = getSubview(view, subviewID); view != nil {
 		view.Session().callFunc("scrollToEnd", view.htmlID())
 	}
 }

session.go

@@ -24,6 +24,7 @@ type bridge interface {
 	callCanvasVarFunc(v any, funcName string, args ...any)
 	callCanvasImageFunc(url string, property string, funcName string, args ...any)
 	createCanvasVar(funcName string, args ...any) any
+	createPath2D(arg string) any
 	updateCanvasProperty(property string, value any)
 	canvasFinish()
 	canvasTextMetrics(htmlID, font, text string) TextMetrics
@@ -35,6 +36,8 @@ type bridge interface {
 
 // SessionContent is the interface of a session content
 type SessionContent interface {
+
+	// CreateRootView will be called by the library to create a root view of the application
 	CreateRootView(session Session) View
 }
 
@@ -86,11 +89,11 @@ type Session interface {
 	RootView() View
 	// Get returns a value of the view (with id defined by the first argument) property with name defined by the second argument.
 	// The type of return value depends on the property. If the property is not set then nil is returned.
-	Get(viewID, tag string) any
+	Get(viewID string, tag PropertyName) any
 	// Set sets the value (third argument) of the property (second argument) of the view with id defined by the first argument.
 	// Return "true" if the value has been set, in the opposite case "false" are returned and
 	// a description of the error is written to the log
-	Set(viewID, tag string, value any) bool
+	Set(viewID string, tag PropertyName, value any) bool
 
 	// DownloadFile downloads (saves) on the client side the file located at the specified path on the server.
 	DownloadFile(path string)
@@ -103,6 +106,8 @@ type Session interface {
 	ClientItem(key string) (string, bool)
 	// SetClientItem stores a key-value pair in the client-side storage
 	SetClientItem(key, value string)
+	// RemoveClientItem removes a key-value pair in the client-side storage
+	RemoveClientItem(key string)
 	// RemoveAllClientItems removes all key-value pair from the client-side storage
 	RemoveAllClientItems()
 
@@ -122,14 +127,14 @@ type Session interface {
 	registerAnimation(props []AnimatedProperty) string
 
 	resolveConstants(value string) (string, bool)
-	checkboxOffImage() string
-	checkboxOnImage() string
+	checkboxOffImage(accentColor Color) string
+	checkboxOnImage(accentColor Color) string
 	radiobuttonOffImage() string
-	radiobuttonOnImage() string
+	radiobuttonOnImage(accentColor Color) string
 
 	viewByHTMLID(id string) View
 	nextViewID() string
-	styleProperty(styleTag, property string) any
+	styleProperty(styleTag string, propertyTag PropertyName) any
 
 	setBridge(events chan DataObject, bridge bridge)
 	writeInitScript(writer *strings.Builder)
@@ -143,16 +148,19 @@ type Session interface {
 	finishUpdateScript(htmlID string)
 	sendResponse()
 	addAnimationCSS(css string)
-	clearAnimation()
-	canvasStart(htmlID string)
+	removeAnimation(keyframe string)
+	htmlPropertyValue(htmlID, name string) string
+
+	canvasStart(htmlID string) bool
 	callCanvasFunc(funcName string, args ...any)
 	createCanvasVar(funcName string, args ...any) any
+	createPath(arg string) any
 	callCanvasVarFunc(v any, funcName string, args ...any)
 	callCanvasImageFunc(url string, property string, funcName string, args ...any)
 	updateCanvasProperty(property string, value any)
 	canvasFinish()
 	canvasTextMetrics(htmlID, font, text string) TextMetrics
-	htmlPropertyValue(htmlID, name string) string
+
 	addToEventsQueue(data DataObject)
 	handleAnswer(command string, data DataObject) bool
 	handleRootSize(data DataObject)
@@ -262,7 +270,7 @@ func (session *sessionData) close() {
 	}
 }
 
-func (session *sessionData) styleProperty(styleTag, propertyTag string) any {
+func (session *sessionData) styleProperty(styleTag string, propertyTag PropertyName) any {
 	if style := session.getCurrentTheme().style(styleTag); style != nil {
 		return style.getRaw(propertyTag)
 	}
@@ -321,7 +329,7 @@ func (session *sessionData) writeInitScript(writer *strings.Builder) {
 		writer.WriteString(`document.getElementById('ruiRootView').innerHTML = '`)
 		buffer := allocStringBuilder()
 		defer freeStringBuilder(buffer)
-		viewHTML(session.rootView, buffer)
+		viewHTML(session.rootView, buffer, "")
 		text := strings.ReplaceAll(buffer.String(), "'", `\'`)
 		writer.WriteString(text)
 		writer.WriteString("';\nscanElementsSize();")
@@ -352,7 +360,7 @@ func (session *sessionData) reload() {
 		buffer := allocStringBuilder()
 		defer freeStringBuilder(buffer)
 
-		viewHTML(session.rootView, buffer)
+		viewHTML(session.rootView, buffer, "")
 		session.bridge.updateInnerHTML("ruiRootView", buffer.String())
 		session.bridge.callFunc("scanElementsSize")
 	}
@@ -368,14 +376,14 @@ func (session *sessionData) setIgnoreViewUpdates(ignore bool) {
 	session.ignoreUpdates = ignore
 }
 
-func (session *sessionData) Get(viewID, tag string) any {
+func (session *sessionData) Get(viewID string, tag PropertyName) any {
 	if view := ViewByID(session.RootView(), viewID); view != nil {
 		return view.Get(tag)
 	}
 	return nil
 }
 
-func (session *sessionData) Set(viewID, tag string, value any) bool {
+func (session *sessionData) Set(viewID string, tag PropertyName, value any) bool {
 	if view := ViewByID(session.RootView(), viewID); view != nil {
 		return view.Set(tag, value)
 	}
@@ -427,20 +435,32 @@ func (session *sessionData) appendToInnerHTML(htmlID, html string) {
 }
 
 func (session *sessionData) updateCSSProperty(htmlID, property, value string) {
-	if !session.ignoreViewUpdates() && session.bridge != nil {
-		session.bridge.updateCSSProperty(htmlID, property, value)
+	if !session.ignoreViewUpdates() {
+		if session.bridge != nil {
+			session.bridge.updateCSSProperty(htmlID, property, value)
+		} else {
+			ErrorLog("No connection")
+		}
 	}
 }
 
 func (session *sessionData) updateProperty(htmlID, property string, value any) {
-	if !session.ignoreViewUpdates() && session.bridge != nil {
-		session.bridge.updateProperty(htmlID, property, value)
+	if !session.ignoreViewUpdates() {
+		if session.bridge != nil {
+			session.bridge.updateProperty(htmlID, property, value)
+		} else {
+			ErrorLog("No connection")
+		}
 	}
 }
 
 func (session *sessionData) removeProperty(htmlID, property string) {
-	if !session.ignoreViewUpdates() && session.bridge != nil {
-		session.bridge.removeProperty(htmlID, property)
+	if !session.ignoreViewUpdates() {
+		if session.bridge != nil {
+			session.bridge.removeProperty(htmlID, property)
+		} else {
+			ErrorLog("No connection")
+		}
 	}
 }
 
@@ -448,37 +468,82 @@ func (session *sessionData) startUpdateScript(htmlID string) bool {
 	if session.bridge != nil {
 		return session.bridge.startUpdateScript(htmlID)
 	}
+	ErrorLog("No connection")
 	return false
 }
 
 func (session *sessionData) finishUpdateScript(htmlID string) {
 	if session.bridge != nil {
 		session.bridge.finishUpdateScript(htmlID)
+	} else {
+		ErrorLog("No connection")
 	}
 }
 
 func (session *sessionData) sendResponse() {
 	if session.bridge != nil {
 		session.bridge.sendResponse()
+	} else {
+		ErrorLog("No connection")
 	}
 }
 
 func (session *sessionData) addAnimationCSS(css string) {
+	session.animationCSS += css
 	if session.bridge != nil {
 		session.bridge.appendAnimationCSS(css)
+	} else {
+		ErrorLog("No connection")
 	}
 }
 
-func (session *sessionData) clearAnimation() {
-	if session.bridge != nil {
-		session.bridge.setAnimationCSS("")
+func (session *sessionData) removeAnimation(keyframe string) {
+	css := session.animationCSS
+	index := strings.Index(css, "@keyframes "+keyframe)
+	if index < 0 {
+		return
+	}
+
+	start := strings.IndexRune(css[index:], '{')
+	if start < 0 {
+		return
+	}
+
+	n := 1
+	end := -1
+	for i := start + index + 1; i < len(css); i++ {
+		if css[i] == '}' {
+			n--
+			if n == 0 {
+				end = i + 1
+				if end < len(css) && css[end] == '\n' {
+					end++
+				}
+				break
+			}
+		} else if css[i] == '{' {
+			n++
+		}
+	}
+
+	if end > index {
+		session.animationCSS = strings.Trim(css[:index]+css[end:], "\n")
+		if session.bridge != nil {
+			session.bridge.setAnimationCSS(session.animationCSS)
+		} else {
+			ErrorLog("No connection")
+		}
 	}
 }
 
-func (session *sessionData) canvasStart(htmlID string) {
+func (session *sessionData) canvasStart(htmlID string) bool {
 	if session.bridge != nil {
 		session.bridge.canvasStart(htmlID)
+		return true
 	}
+
+	ErrorLog("No connection")
+	return false
 }
 
 func (session *sessionData) callCanvasFunc(funcName string, args ...any) {
@@ -500,6 +565,13 @@ func (session *sessionData) createCanvasVar(funcName string, args ...any) any {
 	return nil
 }
 
+func (session *sessionData) createPath(arg string) any {
+	if session.bridge != nil {
+		return session.bridge.createPath2D(arg)
+	}
+	return nil
+}
+
 func (session *sessionData) callCanvasVarFunc(v any, funcName string, args ...any) {
 	if session.bridge != nil && v != nil {
 		session.bridge.callCanvasVarFunc(v, funcName, args...)
@@ -555,6 +627,8 @@ func (session *sessionData) handleAnswer(command string, data DataObject) bool {
 
 	if session.bridge != nil {
 		session.bridge.sendResponse()
+	} else {
+		ErrorLog("No connection")
 	}
 	return true
 }
@@ -711,10 +785,10 @@ func (session *sessionData) handleEvent(command string, data DataObject) {
 		if viewID, ok := data.PropertyValue("id"); ok {
 			if viewID != "body" {
 				if view := session.viewByHTMLID(viewID); view != nil {
-					view.handleCommand(view, command, data)
+					view.handleCommand(view, PropertyName(command), data)
 				}
 			}
-			if command == KeyDownEvent {
+			if command == string(KeyDownEvent) {
 				var event KeyEvent
 				event.init(data)
 				session.hotKey(event)
@@ -818,6 +892,11 @@ func (session *sessionData) SetClientItem(key, value string) {
 	session.bridge.callFunc("localStorageSet", key, value)
 }
 
+func (session *sessionData) RemoveClientItem(key string) {
+	delete(session.clientStorage, key)
+	session.bridge.callFunc("localStorageRemove", key)
+}
+
 func (session *sessionData) RemoveAllClientItems() {
 	session.clientStorage = map[string]string{}
 	session.bridge.callFunc("localStorageClear")

sessionEvents.go

@@ -4,31 +4,42 @@ import "time"
 
 // SessionStartListener is the listener interface of a session start event
 type SessionStartListener interface {
+	// OnStart is a function that is called by the library after the creation of the root view of the application
 	OnStart(session Session)
 }
 
 // SessionFinishListener is the listener interface of a session start event
 type SessionFinishListener interface {
+	// OnFinish is a function that is called by the library when the user closes the application page in the browser
 	OnFinish(session Session)
 }
 
 // SessionResumeListener is the listener interface of a session resume event
 type SessionResumeListener interface {
+	// OnResume is a function that is called by the library when the application page in the client's browser becomes
+	// active and is also called immediately after OnStart
 	OnResume(session Session)
 }
 
 // SessionPauseListener is the listener interface of a session pause event
 type SessionPauseListener interface {
+	// OnPause is a function that is called by the library when the application page in the client's browser becomes
+	// inactive and is also called when the user switches to a different browser tab/window, minimizes the browser,
+	// or switches to another application
 	OnPause(session Session)
 }
 
 // SessionPauseListener is the listener interface of a session disconnect event
 type SessionDisconnectListener interface {
+	// OnDisconnect is a function that is called by the library if the server loses connection with the client and
+	// this happens when the connection is broken
 	OnDisconnect(session Session)
 }
 
 // SessionPauseListener is the listener interface of a session reconnect event
 type SessionReconnectListener interface {
+	// OnReconnect is a function that is called by the library after the server reconnects with the client
+	// and this happens when the connection is restored
 	OnReconnect(session Session)
 }
 

sessionTheme.go

@@ -203,7 +203,7 @@ func (session *sessionData) SetCustomTheme(name string) bool {
 
 const checkImage = `<svg width="16" height="16" version="1.1" viewBox="0 0 16 16" xmlns="http://www.w3.org/2000/svg"><path d="m4 8 3 4 5-8" fill="none" stroke="#fff" stroke-linecap="round" stroke-linejoin="round" stroke-width="2.5"/></svg>`
 
-func (session *sessionData) checkboxImage(checked bool) string {
+func (session *sessionData) checkboxImage(checked bool, accentColor Color) string {
 
 	var borderColor, backgroundColor Color
 	var ok bool
@@ -217,7 +217,9 @@ func (session *sessionData) checkboxImage(checked bool) string {
 	}
 
 	if checked {
-		if backgroundColor, ok = session.Color("ruiHighlightColor"); !ok {
+		if accentColor != 0 {
+			backgroundColor = accentColor
+		} else if backgroundColor, ok = session.Color("ruiHighlightColor"); !ok {
 			backgroundColor = 0xFF1A74E8
 		}
 	} else if backgroundColor, ok = session.Color("ruiBackgroundColor"); !ok {
@@ -244,16 +246,22 @@ func (session *sessionData) checkboxImage(checked bool) string {
 	return buffer.String()
 }
 
-func (session *sessionData) checkboxOffImage() string {
+func (session *sessionData) checkboxOffImage(accentColor Color) string {
+	if accentColor != 0 {
+		return session.checkboxImage(false, accentColor)
+	}
 	if session.checkboxOff == "" {
-		session.checkboxOff = session.checkboxImage(false)
+		session.checkboxOff = session.checkboxImage(false, accentColor)
 	}
 	return session.checkboxOff
 }
 
-func (session *sessionData) checkboxOnImage() string {
+func (session *sessionData) checkboxOnImage(accentColor Color) string {
+	if accentColor != 0 {
+		return session.checkboxImage(true, accentColor)
+	}
 	if session.checkboxOn == "" {
-		session.checkboxOn = session.checkboxImage(true)
+		session.checkboxOn = session.checkboxImage(true, accentColor)
 	}
 	return session.checkboxOn
 }
@@ -285,12 +293,14 @@ func (session *sessionData) radiobuttonOffImage() string {
 	return session.radiobuttonOff
 }
 
-func (session *sessionData) radiobuttonOnImage() string {
+func (session *sessionData) radiobuttonOnImage(accentColor Color) string {
 	if session.radiobuttonOn == "" {
 		var borderColor, backgroundColor Color
 		var ok bool
 
-		if borderColor, ok = session.Color("ruiHighlightColor"); !ok {
+		if accentColor != 0 {
+			borderColor = accentColor
+		} else if borderColor, ok = session.Color("ruiHighlightColor"); !ok {
 			borderColor = 0xFF1A74E8
 		}
 
@@ -313,7 +323,7 @@ func (session *sessionData) Language() string {
 		return session.language
 	}
 
-	if session.languages != nil && len(session.languages) > 0 {
+	if len(session.languages) > 0 {
 		return session.languages[0]
 	}
 
@@ -329,7 +339,7 @@ func (session *sessionData) SetLanguage(lang string) {
 			buffer := allocStringBuilder()
 			defer freeStringBuilder(buffer)
 
-			viewHTML(session.rootView, buffer)
+			viewHTML(session.rootView, buffer, "")
 			session.bridge.updateInnerHTML("ruiRootView", buffer.String())
 		}
 	}

shadow.go

@@ -5,30 +5,110 @@ import (
 	"strings"
 )
 
+// Constants for [ShadowProperty] specific properties
 const (
-	// ColorTag is the name of the color property of the shadow.
-	ColorTag = "color"
-	// Inset is the name of bool property of the shadow. If it is set to "false" (default) then the shadow
-	// is assumed to be a drop shadow (as if the box were raised above the content).
-	// If it is set to  "true" then the shadow to one inside the frame (as if the content was depressed inside the box).
-	// Inset shadows are drawn inside the border (even transparent ones), above the background, but below content.
-	Inset = "inset"
-	// XOffset is the name of the SizeUnit property of the shadow that determines the shadow horizontal offset.
-	// Negative values place the shadow to the left of the element.
-	XOffset = "x-offset"
-	// YOffset is the name of the SizeUnit property of the shadow that determines the shadow vertical offset.
-	// Negative values place the shadow above the element.
-	YOffset = "y-offset"
-	// BlurRadius is the name of the SizeUnit property of the shadow that determines the radius of the blur effect.
-	// The larger this value, the bigger the blur, so the shadow becomes bigger and lighter. Negative values are not allowed.
-	BlurRadius = "blur"
-	// SpreadRadius is the name of the SizeUnit property of the shadow. Positive values will cause the shadow to expand
-	// and grow bigger, negative values will cause the shadow to shrink.
-	SpreadRadius = "spread-radius"
+	// ColorTag is the constant for "color" property tag.
+	//
+	// Used by ColumnSeparatorProperty, BorderProperty, OutlineProperty, ShadowProperty.
+	//
+	// # Usage in ColumnSeparatorProperty
+	//
+	// Line color.
+	//
+	// Supported types: Color, string.
+	//
+	// Internal type is Color, other types converted to it during assignment.
+	// See Color description for more details.
+	//
+	// # Usage in BorderProperty
+	//
+	// Border line color.
+	//
+	// Supported types: Color, string.
+	//
+	// Internal type is Color, other types converted to it during assignment.
+	// See Color description for more details.
+	//
+	// # Usage in OutlineProperty
+	//
+	// Outline line color.
+	//
+	// Supported types: Color, string.
+	//
+	// Internal type is Color, other types converted to it during assignment.
+	// See Color description for more details.
+	//
+	// # Usage in ShadowProperty
+	//
+	// Color property of the shadow.
+	//
+	// Supported types: Color, string.
+	//
+	// Internal type is Color, other types converted to it during assignment.
+	// See Color description for more details.
+	ColorTag PropertyName = "color"
+
+	// Inset is the constant for "inset" property tag.
+	//
+	// Used by ShadowProperty.
+	// Controls whether to draw shadow inside the frame or outside. Inset shadows are drawn inside the border(even transparent
+	// ones), above the background, but below content.
+	//
+	// Supported types: bool, int, string.
+	//
+	// Values:
+	//   - true, 1, "true", "yes", "on", "1" - Drop shadow inside the frame(as if the content was depressed inside the box).
+	//   - false, 0, "false", "no", "off", "0" - Shadow is assumed to be a drop shadow(as if the box were raised above the content).
+	Inset PropertyName = "inset"
+
+	// XOffset is the constant for "x-offset" property tag.
+	//
+	// Used by ShadowProperty.
+	// Determines the shadow horizontal offset. Negative values place the shadow to the left of the element.
+	//
+	// Supported types: SizeUnit, SizeFunc, string, float, int.
+	//
+	// Internal type is SizeUnit, other types converted to it during assignment.
+	// See SizeUnit description for more details.
+	XOffset PropertyName = "x-offset"
+
+	// YOffset is the constant for "y-offset" property tag.
+	//
+	// Used by ShadowProperty.
+	// Determines the shadow vertical offset. Negative values place the shadow above the element.
+	//
+	// Supported types: SizeUnit, SizeFunc, string, float, int.
+	//
+	// Internal type is SizeUnit, other types converted to it during assignment.
+	// See SizeUnit description for more details.
+	YOffset PropertyName = "y-offset"
+
+	// BlurRadius is the constant for "blur" property tag.
+	//
+	// Used by ShadowProperty.
+	// Determines the radius of the blur effect. The larger this value, the bigger the blur, so the shadow becomes bigger and
+	// lighter. Negative values are not allowed.
+	//
+	// Supported types: SizeUnit, SizeFunc, string, float, int.
+	//
+	// Internal type is SizeUnit, other types converted to it during assignment.
+	// See SizeUnit description for more details.
+	BlurRadius PropertyName = "blur"
+
+	// SpreadRadius is the constant for "spread-radius" property tag.
+	//
+	// Used by ShadowProperty.
+	// Positive values will cause the shadow to expand and grow bigger, negative values will cause the shadow to shrink.
+	//
+	// Supported types: SizeUnit, SizeFunc, string, float, int.
+	//
+	// Internal type is SizeUnit, other types converted to it during assignment.
+	// See SizeUnit description for more details.
+	SpreadRadius PropertyName = "spread-radius"
 )
 
-// ViewShadow contains attributes of the view shadow
-type ViewShadow interface {
+// ShadowProperty contains attributes of the view shadow
+type ShadowProperty interface {
 	Properties
 	fmt.Stringer
 	stringWriter
@@ -37,34 +117,36 @@ type ViewShadow interface {
 	visible(session Session) bool
 }
 
-type viewShadowData struct {
-	propertyList
+type shadowPropertyData struct {
+	dataProperty
 }
 
-// NewViewShadow create the new shadow for a view. Arguments:
-// offsetX, offsetY - x and y offset of the shadow
-// blurRadius - the blur radius of the shadow
-// spreadRadius - the spread radius of the shadow
-// color - the color of the shadow
-func NewViewShadow(offsetX, offsetY, blurRadius, spreadRadius SizeUnit, color Color) ViewShadow {
-	return NewShadowWithParams(Params{
-		XOffset:      offsetX,
-		YOffset:      offsetY,
+// NewShadow create the new shadow property for a view. Arguments:
+//   - offsetX, offsetY is x and y offset of the shadow (if the argument is specified as int or float64, the value is considered to be in pixels);
+//   - blurRadius is the blur radius of the shadow (if the argument is specified as int or float64, the value is considered to be in pixels);
+//   - spreadRadius is the spread radius of the shadow (if the argument is specified as int or float64, the value is considered to be in pixels);
+//   - color is the color of the shadow.
+func NewShadow[xOffsetType SizeUnit | int | float64, yOffsetType SizeUnit | int | float64, blurType SizeUnit | int | float64, spreadType SizeUnit | int | float64](
+	xOffset xOffsetType, yOffset yOffsetType, blurRadius blurType, spreadRadius spreadType, color Color) ShadowProperty {
+	return NewShadowProperty(Params{
+		XOffset:      xOffset,
+		YOffset:      yOffset,
 		BlurRadius:   blurRadius,
 		SpreadRadius: spreadRadius,
 		ColorTag:     color,
 	})
 }
 
-// NewInsetViewShadow create the new inset shadow for a view. Arguments:
-// offsetX, offsetY - x and y offset of the shadow
-// blurRadius - the blur radius of the shadow
-// spreadRadius - the spread radius of the shadow
-// color - the color of the shadow
-func NewInsetViewShadow(offsetX, offsetY, blurRadius, spreadRadius SizeUnit, color Color) ViewShadow {
-	return NewShadowWithParams(Params{
-		XOffset:      offsetX,
-		YOffset:      offsetY,
+// NewInsetShadow create the new inset shadow property for a view. Arguments:
+//   - offsetX, offsetY is x and y offset of the shadow (if the argument is specified as int or float64, the value is considered to be in pixels);
+//   - blurRadius is the blur radius of the shadow (if the argument is specified as int or float64, the value is considered to be in pixels);
+//   - spreadRadius is the spread radius of the shadow (if the argument is specified as int or float64, the value is considered to be in pixels);
+//   - color is the color of the shadow.
+func NewInsetShadow[xOffsetType SizeUnit | int | float64, yOffsetType SizeUnit | int | float64, blurType SizeUnit | int | float64, spreadType SizeUnit | int | float64](
+	xOffset xOffsetType, yOffset yOffsetType, blurRadius blurType, spreadRadius spreadType, color Color) ShadowProperty {
+	return NewShadowProperty(Params{
+		XOffset:      xOffset,
+		YOffset:      yOffset,
 		BlurRadius:   blurRadius,
 		SpreadRadius: spreadRadius,
 		ColorTag:     color,
@@ -72,66 +154,57 @@ func NewInsetViewShadow(offsetX, offsetY, blurRadius, spreadRadius SizeUnit, col
 	})
 }
 
-// NewTextShadow create the new text shadow. Arguments:
-// offsetX, offsetY - x and y offset of the shadow
-// blurRadius - the blur radius of the shadow
-// color - the color of the shadow
-func NewTextShadow(offsetX, offsetY, blurRadius SizeUnit, color Color) ViewShadow {
-	return NewShadowWithParams(Params{
-		XOffset:    offsetX,
-		YOffset:    offsetY,
+// NewTextShadow create the new text shadow property. Arguments:
+//   - offsetX, offsetY is the x- and y-offset of the shadow (if the argument is specified as int or float64, the value is considered to be in pixels);
+//   - blurRadius is the blur radius of the shadow (if the argument is specified as int or float64, the value is considered to be in pixels);
+//   - color is the color of the shadow.
+func NewTextShadow[xOffsetType SizeUnit | int | float64, yOffsetType SizeUnit | int | float64, blurType SizeUnit | int | float64](
+	xOffset xOffsetType, yOffset yOffsetType, blurRadius blurType, color Color) ShadowProperty {
+	return NewShadowProperty(Params{
+		XOffset:    xOffset,
+		YOffset:    yOffset,
 		BlurRadius: blurRadius,
 		ColorTag:   color,
 	})
 }
 
-// NewShadowWithParams create the new shadow for a view.
-func NewShadowWithParams(params Params) ViewShadow {
-	shadow := new(viewShadowData)
-	shadow.propertyList.init()
+// NewShadowProperty create the new shadow property for a view.
+//
+// The following properties can be used:
+//   - "color" (ColorTag). Determines the color of the shadow (Color);
+//   - "x-offset" (XOffset). Determines the shadow horizontal offset (SizeUnit);
+//   - "y-offset" (YOffset). Determines the shadow vertical offset (SizeUnit);
+//   - "blur" (BlurRadius). Determines the radius of the blur effect (SizeUnit);
+//   - "spread-radius" (SpreadRadius). Positive values (SizeUnit) will cause the shadow to expand and grow bigger, negative values will cause the shadow to shrink;
+//   - "inset" (Inset). Controls (bool) whether to draw shadow inside the frame or outside.
+func NewShadowProperty(params Params) ShadowProperty {
+	shadow := new(shadowPropertyData)
+	shadow.init()
+
 	if params != nil {
-		for _, tag := range []string{ColorTag, Inset, XOffset, YOffset, BlurRadius, SpreadRadius} {
+		for _, tag := range []PropertyName{ColorTag, Inset, XOffset, YOffset, BlurRadius, SpreadRadius} {
 			if value, ok := params[tag]; ok && value != nil {
-				shadow.Set(tag, value)
+				shadow.set(shadow, tag, value)
 			}
 		}
 	}
 	return shadow
 }
 
-// parseViewShadow parse DataObject and create ViewShadow object
-func parseViewShadow(object DataObject) ViewShadow {
-	shadow := new(viewShadowData)
-	shadow.propertyList.init()
+// parseShadowProperty parse DataObject and create ShadowProperty object
+func parseShadowProperty(object DataObject) ShadowProperty {
+	shadow := new(shadowPropertyData)
+	shadow.init()
 	parseProperties(shadow, object)
 	return shadow
 }
 
-func (shadow *viewShadowData) Remove(tag string) {
-	delete(shadow.properties, strings.ToLower(tag))
+func (shadow *shadowPropertyData) init() {
+	shadow.dataProperty.init()
+	shadow.supportedProperties = []PropertyName{ColorTag, Inset, XOffset, YOffset, BlurRadius, SpreadRadius}
 }
 
-func (shadow *viewShadowData) Set(tag string, value any) bool {
-	if value == nil {
-		shadow.Remove(tag)
-		return true
-	}
-
-	tag = strings.ToLower(tag)
-	switch tag {
-	case ColorTag, Inset, XOffset, YOffset, BlurRadius, SpreadRadius:
-		return shadow.propertyList.Set(tag, value)
-	}
-
-	ErrorLogF(`"%s" property is not supported by Shadow`, tag)
-	return false
-}
-
-func (shadow *viewShadowData) Get(tag string) any {
-	return shadow.propertyList.Get(strings.ToLower(tag))
-}
-
-func (shadow *viewShadowData) cssStyle(buffer *strings.Builder, session Session, lead string) bool {
+func (shadow *shadowPropertyData) cssStyle(buffer *strings.Builder, session Session, lead string) bool {
 	color, _ := colorProperty(shadow, ColorTag, session)
 	offsetX, _ := sizeProperty(shadow, XOffset, session)
 	offsetY, _ := sizeProperty(shadow, YOffset, session)
@@ -163,7 +236,7 @@ func (shadow *viewShadowData) cssStyle(buffer *strings.Builder, session Session,
 	return true
 }
 
-func (shadow *viewShadowData) cssTextStyle(buffer *strings.Builder, session Session, lead string) bool {
+func (shadow *shadowPropertyData) cssTextStyle(buffer *strings.Builder, session Session, lead string) bool {
 	color, _ := colorProperty(shadow, ColorTag, session)
 	offsetX, _ := sizeProperty(shadow, XOffset, session)
 	offsetY, _ := sizeProperty(shadow, YOffset, session)
@@ -187,7 +260,7 @@ func (shadow *viewShadowData) cssTextStyle(buffer *strings.Builder, session Sess
 	return true
 }
 
-func (shadow *viewShadowData) visible(session Session) bool {
+func (shadow *shadowPropertyData) visible(session Session) bool {
 	color, _ := colorProperty(shadow, ColorTag, session)
 	offsetX, _ := sizeProperty(shadow, XOffset, session)
 	offsetY, _ := sizeProperty(shadow, YOffset, session)
@@ -204,11 +277,11 @@ func (shadow *viewShadowData) visible(session Session) bool {
 	return true
 }
 
-func (shadow *viewShadowData) String() string {
+func (shadow *shadowPropertyData) String() string {
 	return runStringWriter(shadow)
 }
 
-func (shadow *viewShadowData) writeString(buffer *strings.Builder, indent string) {
+func (shadow *shadowPropertyData) writeString(buffer *strings.Builder, indent string) {
 	buffer.WriteString("_{ ")
 	comma := false
 	for _, tag := range shadow.AllTags() {
@@ -216,7 +289,7 @@ func (shadow *viewShadowData) writeString(buffer *strings.Builder, indent string
 			if comma {
 				buffer.WriteString(", ")
 			}
-			buffer.WriteString(tag)
+			buffer.WriteString(string(tag))
 			buffer.WriteString(" = ")
 			writePropertyValue(buffer, tag, value, indent)
 			comma = true
@@ -225,41 +298,41 @@ func (shadow *viewShadowData) writeString(buffer *strings.Builder, indent string
 	buffer.WriteString(" }")
 }
 
-func (properties *propertyList) setShadow(tag string, value any) bool {
+func setShadowProperty(properties Properties, tag PropertyName, value any) bool {
 
 	if value == nil {
-		delete(properties.properties, tag)
+		properties.setRaw(tag, nil)
 		return true
 	}
 
 	switch value := value.(type) {
-	case ViewShadow:
-		properties.properties[tag] = []ViewShadow{value}
+	case ShadowProperty:
+		properties.setRaw(tag, []ShadowProperty{value})
 
-	case []ViewShadow:
+	case []ShadowProperty:
 		if len(value) == 0 {
-			delete(properties.properties, tag)
+			properties.setRaw(tag, nil)
 		} else {
-			properties.properties[tag] = value
+			properties.setRaw(tag, value)
 		}
 
 	case DataValue:
 		if !value.IsObject() {
 			return false
 		}
-		properties.properties[tag] = []ViewShadow{parseViewShadow(value.Object())}
+		properties.setRaw(tag, []ShadowProperty{parseShadowProperty(value.Object())})
 
 	case []DataValue:
-		shadows := []ViewShadow{}
+		shadows := []ShadowProperty{}
 		for _, data := range value {
 			if data.IsObject() {
-				shadows = append(shadows, parseViewShadow(data.Object()))
+				shadows = append(shadows, parseShadowProperty(data.Object()))
 			}
 		}
 		if len(shadows) == 0 {
 			return false
 		}
-		properties.properties[tag] = shadows
+		properties.setRaw(tag, shadows)
 
 	case string:
 		obj := NewDataObject(value)
@@ -267,7 +340,7 @@ func (properties *propertyList) setShadow(tag string, value any) bool {
 			notCompatibleType(tag, value)
 			return false
 		}
-		properties.properties[tag] = []ViewShadow{parseViewShadow(obj)}
+		properties.setRaw(tag, []ShadowProperty{parseShadowProperty(obj)})
 
 	default:
 		notCompatibleType(tag, value)
@@ -277,20 +350,20 @@ func (properties *propertyList) setShadow(tag string, value any) bool {
 	return true
 }
 
-func getShadows(properties Properties, tag string) []ViewShadow {
+func getShadows(properties Properties, tag PropertyName) []ShadowProperty {
 	if value := properties.Get(tag); value != nil {
 		switch value := value.(type) {
-		case []ViewShadow:
+		case []ShadowProperty:
 			return value
 
-		case ViewShadow:
-			return []ViewShadow{value}
+		case ShadowProperty:
+			return []ShadowProperty{value}
 		}
 	}
-	return []ViewShadow{}
+	return []ShadowProperty{}
 }
 
-func shadowCSS(properties Properties, tag string, session Session) string {
+func shadowCSS(properties Properties, tag PropertyName, session Session) string {
 	shadows := getShadows(properties, tag)
 	if len(shadows) == 0 {
 		return ""

sizeFunc.go

@@ -7,11 +7,15 @@ import (
 )
 
 // SizeFunc describes a function that calculates the SizeUnit size.
+//
 // Used as the value of the SizeUnit properties.
-// "min", "max", "clamp", "sum", "sub", "mul", and "div" functions are available.
+//
+// "min", "max", "clamp", "sum", "sub", "mul", "div", mod,
+// "round", "round-up", "round-down" and "round-to-zero" functions are available.
 type SizeFunc interface {
 	fmt.Stringer
-	// Name() returns the function name: "min", "max", "clamp", "sum", "sub", "mul", or "div"
+	// Name() returns the function name: "min", "max", "clamp", "sum", "sub", "mul",
+	// "div", "mod", "rem", "round", "round-up", "round-down" or "round-to-zero"
 	Name() string
 	// Args() returns a list of function arguments
 	Args() []any
@@ -28,7 +32,9 @@ type sizeFuncData struct {
 func parseSizeFunc(text string) SizeFunc {
 	text = strings.Trim(text, " ")
 
-	for _, tag := range []string{"min", "max", "sum", "sub", "mul", "div", "clamp"} {
+	for _, tag := range []string{
+		"min", "max", "sum", "sub", "mul", "div", "mod", "rem", "clamp",
+		"round-up", "round-down", "round-to-zero", "round"} {
 		if strings.HasPrefix(text, tag) {
 			text = strings.Trim(strings.TrimPrefix(text, tag), " ")
 			last := len(text) - 1
@@ -59,7 +65,7 @@ func parseSizeFunc(text string) SizeFunc {
 
 				args = append(args, text[start:])
 				switch tag {
-				case "sub", "mul", "div":
+				case "sub", "mul", "div", "mod", "rem", "round-up", "round-down", "round-to-zero", "round":
 					if len(args) != 2 {
 						ErrorLogF(`"%s" function needs 2 arguments`, tag)
 						return nil
@@ -73,7 +79,9 @@ func parseSizeFunc(text string) SizeFunc {
 
 				data := new(sizeFuncData)
 				data.tag = tag
-				if data.parseArgs(args, tag == "mul" || tag == "div") {
+				if data.parseArgs(args, tag == "mul" || tag == "div" || tag == "mod" ||
+					tag == "rem" || tag == "round-up" || tag == "round-down" ||
+					tag == "round-to-zero" || tag == "round") {
 					return data
 				}
 			}
@@ -92,19 +100,25 @@ func (data *sizeFuncData) parseArgs(args []any, allowNumber bool) bool {
 	numberArg := func(index int, value float64) bool {
 		if allowNumber {
 			if index == 1 {
-				if value == 0 && data.tag == "div" {
-					ErrorLog(`Division by 0 in div function`)
-					return false
+				if value == 0 {
+					if data.tag == "div" || data.tag == "mod" {
+						ErrorLogF(`Division by 0 in "%s" function`, data.tag)
+						return false
+					}
+					if data.tag == "round" || data.tag == "round-up" ||
+						data.tag == "round-down" || data.tag == "round-to-zero" {
+						ErrorLogF(`The rounding interval is 0 in "%s" function`, data.tag)
+						return false
+					}
 				}
 				data.args = append(data.args, value)
 				return true
 			} else {
 				ErrorLogF(`Only the second %s function argument can be a number`, data.tag)
-				return false
 			}
+		} else {
+			ErrorLogF(`The %s function argument can't be a number`, data.tag)
 		}
-
-		ErrorLogF(`The %s function argument can't be a number`, data.tag)
 		return false
 	}
 
@@ -219,7 +233,7 @@ func (data *sizeFuncData) writeCSS(topFunc string, buffer *strings.Builder, sess
 		case "":
 			buffer.WriteString("calc(")
 
-		case "min", "max", "clamp":
+		case "min", "max", "clamp", "mod", "rem", "round", "round-up", "round-down", "round-to-zero":
 			bracket = false
 
 		default:
@@ -228,10 +242,22 @@ func (data *sizeFuncData) writeCSS(topFunc string, buffer *strings.Builder, sess
 	}
 
 	switch data.tag {
-	case "min", "max", "clamp":
+	case "min", "max", "clamp", "mod", "rem":
 		buffer.WriteString(data.tag)
 		buffer.WriteRune('(')
 
+	case "round":
+		buffer.WriteString("round(nearest, ")
+
+	case "round-up":
+		buffer.WriteString("round(up, ")
+
+	case "round-down":
+		buffer.WriteString("round(down, ")
+
+	case "round-to-zero":
+		buffer.WriteString("round(to-zero, ")
+
 	case "sum":
 		mathFunc(" + ")
 
@@ -287,7 +313,7 @@ func (data *sizeFuncData) writeCSS(topFunc string, buffer *strings.Builder, sess
 }
 
 // MaxSize creates a SizeUnit function that calculates the maximum argument.
-// Valid argument types are SizeUnit, SizeFunc and a string which is a text description of SizeUnit or SizeFunc
+// Valid arguments types are SizeUnit, SizeFunc and a string which is a text description of SizeUnit or SizeFunc
 func MaxSize(arg0, arg1 any, args ...any) SizeFunc {
 	data := new(sizeFuncData)
 	data.tag = "max"
@@ -298,7 +324,7 @@ func MaxSize(arg0, arg1 any, args ...any) SizeFunc {
 }
 
 // MinSize creates a SizeUnit function that calculates the minimum argument.
-// Valid argument types are SizeUnit, SizeFunc and a string which is a text description of SizeUnit or SizeFunc.
+// Valid arguments types are SizeUnit, SizeFunc and a string which is a text description of SizeUnit or SizeFunc.
 func MinSize(arg0, arg1 any, args ...any) SizeFunc {
 	data := new(sizeFuncData)
 	data.tag = "min"
@@ -309,7 +335,7 @@ func MinSize(arg0, arg1 any, args ...any) SizeFunc {
 }
 
 // SumSize creates a SizeUnit function that calculates the sum of arguments.
-// Valid argument types are SizeUnit, SizeFunc and a string which is a text description of SizeUnit or SizeFunc.
+// Valid arguments types are SizeUnit, SizeFunc and a string which is a text description of SizeUnit or SizeFunc.
 func SumSize(arg0, arg1 any, args ...any) SizeFunc {
 	data := new(sizeFuncData)
 	data.tag = "sum"
@@ -320,7 +346,7 @@ func SumSize(arg0, arg1 any, args ...any) SizeFunc {
 }
 
 // SumSize creates a SizeUnit function that calculates the result of subtracting the arguments (arg1 - arg2).
-// Valid argument types are SizeUnit, SizeFunc and a string which is a text description of SizeUnit or SizeFunc.
+// Valid arguments types are SizeUnit, SizeFunc and a string which is a text description of SizeUnit or SizeFunc.
 func SubSize(arg0, arg1 any) SizeFunc {
 	data := new(sizeFuncData)
 	data.tag = "sub"
@@ -331,7 +357,7 @@ func SubSize(arg0, arg1 any) SizeFunc {
 }
 
 // MulSize creates a SizeUnit function that calculates the result of multiplying the arguments (arg1 * arg2).
-// Valid argument types are SizeUnit, SizeFunc and a string which is a text description of SizeUnit or SizeFunc.
+// Valid arguments types are SizeUnit, SizeFunc and a string which is a text description of SizeUnit or SizeFunc.
 // The second argument can also be a number (float32, float32, int, int8...int64, uint, uint8...unit64)
 // or a string which is a text representation of a number.
 func MulSize(arg0, arg1 any) SizeFunc {
@@ -344,7 +370,7 @@ func MulSize(arg0, arg1 any) SizeFunc {
 }
 
 // DivSize creates a SizeUnit function that calculates the result of dividing the arguments (arg1 / arg2).
-// Valid argument types are SizeUnit, SizeFunc and a string which is a text description of SizeUnit or SizeFunc.
+// Valid arguments types are SizeUnit, SizeFunc and a string which is a text description of SizeUnit or SizeFunc.
 // The second argument can also be a number (float32, float32, int, int8...int64, uint, uint8...unit64)
 // or a string which is a text representation of a number.
 func DivSize(arg0, arg1 any) SizeFunc {
@@ -356,13 +382,103 @@ func DivSize(arg0, arg1 any) SizeFunc {
 	return data
 }
 
+// RemSize creates a SizeUnit function that calculates the remainder of a division operation
+// with the same sign as the dividend (arg1 % arg2).
+// Valid arguments types are SizeUnit, SizeFunc and a string which is a text description of SizeUnit or SizeFunc.
+// The second argument can also be a number (float32, float32, int, int8...int64, uint, uint8...unit64)
+// or a string which is a text representation of a number.
+func RemSize(arg0, arg1 any) SizeFunc {
+	data := new(sizeFuncData)
+	data.tag = "rem"
+	if !data.parseArgs([]any{arg0, arg1}, true) {
+		return nil
+	}
+	return data
+}
+
+// ModSize creates a SizeUnit function that calculates the remainder of a division operation
+// with the same sign as the divisor (arg1 % arg2).
+// Valid arguments types are SizeUnit, SizeFunc and a string which is a text description of SizeUnit or SizeFunc.
+// The second argument can also be a number (float32, float32, int, int8...int64, uint, uint8...unit64)
+// or a string which is a text representation of a number.
+func ModSize(arg0, arg1 any) SizeFunc {
+	data := new(sizeFuncData)
+	data.tag = "mod"
+	if !data.parseArgs([]any{arg0, arg1}, true) {
+		return nil
+	}
+	return data
+}
+
+// RoundSize creates a SizeUnit function that calculates a rounded number.
+// The function rounds valueToRound (first argument) to the nearest integer multiple
+// of roundingInterval (second argument), which may be either above or below the value.
+// If the valueToRound is half way between the rounding targets above and below (neither is "nearest"), it will be rounded up.
+// Valid arguments types are SizeUnit, SizeFunc and a string which is a text description of SizeUnit or SizeFunc.
+// The second argument can also be a number (float32, float32, int, int8...int64, uint, uint8...unit64)
+// or a string which is a text representation of a number.
+func RoundSize(valueToRound, roundingInterval any) SizeFunc {
+	data := new(sizeFuncData)
+	data.tag = "round"
+	if !data.parseArgs([]any{valueToRound, roundingInterval}, true) {
+		return nil
+	}
+	return data
+}
+
+// RoundUpSize creates a SizeUnit function that calculates a rounded number.
+// The function rounds valueToRound (first argument) up to the nearest integer multiple
+// of roundingInterval (second argument) (if the value is negative, it will become "more positive").
+// Valid arguments types are SizeUnit, SizeFunc and a string which is a text description of SizeUnit or SizeFunc.
+// The second argument can also be a number (float32, float32, int, int8...int64, uint, uint8...unit64)
+// or a string which is a text representation of a number.
+func RoundUpSize(valueToRound, roundingInterval any) SizeFunc {
+	data := new(sizeFuncData)
+	data.tag = "round-up"
+	if !data.parseArgs([]any{valueToRound, roundingInterval}, true) {
+		return nil
+	}
+	return data
+}
+
+// RoundDownSize creates a SizeUnit function that calculates a rounded number.
+// The function rounds valueToRound (first argument) down to the nearest integer multiple
+// of roundingInterval (second argument) (if the value is negative, it will become "more negative").
+// Valid arguments types are SizeUnit, SizeFunc and a string which is a text description of SizeUnit or SizeFunc.
+// The second argument can also be a number (float32, float32, int, int8...int64, uint, uint8...unit64)
+// or a string which is a text representation of a number.
+func RoundDownSize(valueToRound, roundingInterval any) SizeFunc {
+	data := new(sizeFuncData)
+	data.tag = "round-down"
+	if !data.parseArgs([]any{valueToRound, roundingInterval}, true) {
+		return nil
+	}
+	return data
+}
+
+// RoundToZeroSize creates a SizeUnit function that calculates a rounded number.
+// The function rounds valueToRound (first argument) to the nearest integer multiple
+// of roundingInterval (second argument), which may be either above or below the value.
+// If the valueToRound is half way between the rounding targets above and below.
+// Valid arguments types are SizeUnit, SizeFunc and a string which is a text description of SizeUnit or SizeFunc.
+// The second argument can also be a number (float32, float32, int, int8...int64, uint, uint8...unit64)
+// or a string which is a text representation of a number.
+func RoundToZeroSize(valueToRound, roundingInterval any) SizeFunc {
+	data := new(sizeFuncData)
+	data.tag = "round-to-zero"
+	if !data.parseArgs([]any{valueToRound, roundingInterval}, true) {
+		return nil
+	}
+	return data
+}
+
 // ClampSize creates a SizeUnit function whose the result is calculated as follows:
 //
 //	min ≤ value ≤ max -> value;
 //	value < min -> min;
 //	max < value -> max;
 //
-// Valid argument types are SizeUnit, SizeFunc and a string which is a text description of SizeUnit or SizeFunc.
+// Valid arguments types are SizeUnit, SizeFunc and a string which is a text description of SizeUnit or SizeFunc.
 func ClampSize(min, value, max any) SizeFunc {
 	data := new(sizeFuncData)
 	data.tag = "clamp"

sizeUnit.go

@@ -13,6 +13,7 @@ import (
 // SizeInDIP, SizeInPt, SizeInInch, SizeInMM, SizeInFraction
 type SizeUnitType uint8
 
+// Constants which represent values of a [SizeUnitType]
 const (
 	// Auto is the SizeUnit type: default value.
 	Auto SizeUnitType = 0
@@ -44,8 +45,14 @@ const (
 
 // SizeUnit describe a size (Value field) and size unit (Type field).
 type SizeUnit struct {
-	Type     SizeUnitType
-	Value    float64
+	// Type or dimension of the value
+	Type SizeUnitType
+
+	// Value of the size in Type units
+	Value float64
+
+	// Function representation of a size unit.
+	// When setting this value type should be set to SizeFunction
 	Function SizeFunc
 }
 
@@ -55,53 +62,53 @@ func AutoSize() SizeUnit {
 }
 
 // Px creates SizeUnit with SizeInPixel type
-func Px(value float64) SizeUnit {
-	return SizeUnit{SizeInPixel, value, nil}
+func Px[T float64 | float32 | int | int8 | int16 | int32 | int64 | uint | uint8 | uint16 | uint32 | uint64](value T) SizeUnit {
+	return SizeUnit{Type: SizeInPixel, Value: float64(value), Function: nil}
 }
 
 // Em creates SizeUnit with SizeInEM type
-func Em(value float64) SizeUnit {
-	return SizeUnit{SizeInEM, value, nil}
+func Em[T float64 | float32 | int | int8 | int16 | int32 | int64 | uint | uint8 | uint16 | uint32 | uint64](value T) SizeUnit {
+	return SizeUnit{Type: SizeInEM, Value: float64(value), Function: nil}
 }
 
 // Ex creates SizeUnit with SizeInEX type
-func Ex(value float64) SizeUnit {
-	return SizeUnit{SizeInEX, value, nil}
+func Ex[T float64 | float32 | int | int8 | int16 | int32 | int64 | uint | uint8 | uint16 | uint32 | uint64](value T) SizeUnit {
+	return SizeUnit{Type: SizeInEX, Value: float64(value), Function: nil}
 }
 
 // Percent creates SizeUnit with SizeInDIP type
-func Percent(value float64) SizeUnit {
-	return SizeUnit{SizeInPercent, value, nil}
+func Percent[T float64 | float32 | int | int8 | int16 | int32 | int64 | uint | uint8 | uint16 | uint32 | uint64](value T) SizeUnit {
+	return SizeUnit{Type: SizeInPercent, Value: float64(value), Function: nil}
 }
 
 // Pt creates SizeUnit with SizeInPt type
-func Pt(value float64) SizeUnit {
-	return SizeUnit{SizeInPt, value, nil}
+func Pt[T float64 | float32 | int | int8 | int16 | int32 | int64 | uint | uint8 | uint16 | uint32 | uint64](value T) SizeUnit {
+	return SizeUnit{Type: SizeInPt, Value: float64(value), Function: nil}
 }
 
 // Pc creates SizeUnit with SizeInPc type
-func Pc(value float64) SizeUnit {
-	return SizeUnit{SizeInPc, value, nil}
+func Pc[T float64 | float32 | int | int8 | int16 | int32 | int64 | uint | uint8 | uint16 | uint32 | uint64](value T) SizeUnit {
+	return SizeUnit{Type: SizeInPc, Value: float64(value), Function: nil}
 }
 
 // Mm creates SizeUnit with SizeInMM type
-func Mm(value float64) SizeUnit {
-	return SizeUnit{SizeInMM, value, nil}
+func Mm[T float64 | float32 | int | int8 | int16 | int32 | int64 | uint | uint8 | uint16 | uint32 | uint64](value T) SizeUnit {
+	return SizeUnit{Type: SizeInMM, Value: float64(value), Function: nil}
 }
 
 // Cm creates SizeUnit with SizeInCM type
-func Cm(value float64) SizeUnit {
-	return SizeUnit{SizeInCM, value, nil}
+func Cm[T float64 | float32 | int | int8 | int16 | int32 | int64 | uint | uint8 | uint16 | uint32 | uint64](value T) SizeUnit {
+	return SizeUnit{Type: SizeInCM, Value: float64(value), Function: nil}
 }
 
 // Inch creates SizeUnit with SizeInInch type
-func Inch(value float64) SizeUnit {
-	return SizeUnit{SizeInInch, value, nil}
+func Inch[T float64 | float32 | int | int8 | int16 | int32 | int64 | uint | uint8 | uint16 | uint32 | uint64](value T) SizeUnit {
+	return SizeUnit{Type: SizeInInch, Value: float64(value), Function: nil}
 }
 
 // Fr creates SizeUnit with SizeInFraction type
-func Fr(value float64) SizeUnit {
-	return SizeUnit{SizeInFraction, value, nil}
+func Fr[T float64 | float32 | int | int8 | int16 | int32 | int64 | uint | uint8 | uint16 | uint32 | uint64](value T) SizeUnit {
+	return SizeUnit{SizeInFraction, float64(value), nil}
 }
 
 // Equal compare two SizeUnit. Return true if SizeUnit are equal

svgImageView.go

@@ -7,7 +7,7 @@ import (
 	"strings"
 )
 
-// SvgImageView - image View
+// SvgImageView represents an SvgImageView view
 type SvgImageView interface {
 	View
 }
@@ -25,7 +25,7 @@ func NewSvgImageView(session Session, params Params) SvgImageView {
 }
 
 func newSvgImageView(session Session) View {
-	return NewSvgImageView(session, nil)
+	return new(svgImageViewData) // NewSvgImageView(session, nil)
 }
 
 // Init initialize fields of imageView by default values
@@ -33,14 +33,14 @@ func (imageView *svgImageViewData) init(session Session) {
 	imageView.viewData.init(session)
 	imageView.tag = "SvgImageView"
 	imageView.systemClass = "ruiSvgImageView"
+	imageView.normalize = normalizeSvgImageViewTag
+	imageView.set = imageView.setFunc
+	imageView.changed = imageView.propertyChanged
+
 }
 
-func (imageView *svgImageViewData) String() string {
-	return getViewString(imageView, nil)
-}
-
-func (imageView *svgImageViewData) normalizeTag(tag string) string {
-	tag = strings.ToLower(tag)
+func normalizeSvgImageViewTag(tag PropertyName) PropertyName {
+	tag = defaultNormalize(tag)
 	switch tag {
 	case Source, "source":
 		tag = Content
@@ -54,57 +54,63 @@ func (imageView *svgImageViewData) normalizeTag(tag string) string {
 	return tag
 }
 
-func (imageView *svgImageViewData) Remove(tag string) {
-	imageView.remove(imageView.normalizeTag(tag))
-}
-
-func (imageView *svgImageViewData) remove(tag string) {
-	imageView.viewData.remove(tag)
-
-	if imageView.created {
-		switch tag {
-		case Content:
-			updateInnerHTML(imageView.htmlID(), imageView.session)
-		}
-	}
-}
-
-func (imageView *svgImageViewData) Set(tag string, value any) bool {
-	return imageView.set(imageView.normalizeTag(tag), value)
-}
-
-func (imageView *svgImageViewData) set(tag string, value any) bool {
-	if value == nil {
-		imageView.remove(tag)
-		return true
-	}
-
+func (imageView *svgImageViewData) setFunc(tag PropertyName, value any) []PropertyName {
 	switch tag {
 	case Content:
 		if text, ok := value.(string); ok {
-			imageView.properties[Content] = text
-			if imageView.created {
-				updateInnerHTML(imageView.htmlID(), imageView.session)
-			}
-			imageView.propertyChangedEvent(Content)
-			return true
+			imageView.setRaw(Content, text)
+			return []PropertyName{tag}
 		}
 		notCompatibleType(Source, value)
-		return false
+		return nil
 
 	default:
-		return imageView.viewData.set(tag, value)
+		return imageView.viewData.setFunc(tag, value)
 	}
 }
 
-func (imageView *svgImageViewData) Get(tag string) any {
-	return imageView.viewData.get(imageView.normalizeTag(tag))
+func (imageView *svgImageViewData) propertyChanged(tag PropertyName) {
+	switch tag {
+	case Content:
+		updateInnerHTML(imageView.htmlID(), imageView.Session())
+
+	default:
+		imageView.viewData.propertyChanged(tag)
+	}
 }
 
 func (imageView *svgImageViewData) htmlTag() string {
 	return "div"
 }
 
+func (imageView *svgImageViewData) writeSvg(data []byte, buffer *strings.Builder) {
+	text := string(data)
+	index := strings.Index(text, "<svg")
+	if index > 0 {
+		text = text[index:]
+	}
+
+	index = strings.Index(text, "\n")
+	for index >= 0 {
+		if index > 0 && text[index-1] == '\r' {
+			buffer.WriteString(text[:index-1])
+		} else {
+			buffer.WriteString(text[:index])
+		}
+
+		end := len(text)
+		index++
+		for index < end && (text[index] == ' ' || text[index] == '\t' || text[index] == '\r' || text[index] == '\n') {
+			index++
+		}
+
+		text = text[index:]
+		index = strings.Index(text, "\n")
+	}
+
+	buffer.WriteString(text)
+}
+
 func (imageView *svgImageViewData) htmlSubviews(self View, buffer *strings.Builder) {
 	if value := imageView.getRaw(Content); value != nil {
 		if content, ok := value.(string); ok && content != "" {
@@ -117,13 +123,13 @@ func (imageView *svgImageViewData) htmlSubviews(self View, buffer *strings.Build
 			if image, ok := resources.images[content]; ok {
 				if image.fs != nil {
 					if data, err := image.fs.ReadFile(image.path); err == nil {
-						buffer.WriteString(string(data))
+						imageView.writeSvg(data, buffer)
 						return
 					} else {
 						DebugLog(err.Error())
 					}
 				} else if data, err := os.ReadFile(image.path); err == nil {
-					buffer.WriteString(string(data))
+					imageView.writeSvg(data, buffer)
 					return
 				} else {
 					DebugLog(err.Error())
@@ -135,7 +141,7 @@ func (imageView *svgImageViewData) htmlSubviews(self View, buffer *strings.Build
 				if err == nil {
 					defer resp.Body.Close()
 					if body, err := io.ReadAll(resp.Body); err == nil {
-						buffer.WriteString(string(body))
+						imageView.writeSvg(body, buffer)
 						return
 					}
 				}

tableAdapter.go

@@ -1,6 +1,6 @@
 package rui
 
-// TableAdapter describes the TableView content
+// TableAdapter describes the [TableView] content
 type TableAdapter interface {
 	// RowCount returns number of rows in the table
 	RowCount() int
@@ -9,57 +9,70 @@ type TableAdapter interface {
 	ColumnCount() int
 
 	// Cell returns the contents of a table cell. The function can return elements of the following types:
-	// * string
-	// * rune
-	// * float32, float64
-	// * integer values: int, int8, int16, int32, int64, uint, uint8, uint16, uint32, uint64
-	// * bool
-	// * rui.Color
-	// * rui.View
-	// * fmt.Stringer
-	// * rui.VerticalTableJoin, rui.HorizontalTableJoin
+	//   - string
+	//   - rune
+	//   - float32, float64
+	//   - integer values: int, int8, int16, int32, int64, uint, uint8, uint16, uint32, uint64
+	//   - bool
+	//   - rui.Color
+	//   - rui.View
+	//   - fmt.Stringer
+	//   - rui.VerticalTableJoin, rui.HorizontalTableJoin
 	Cell(row, column int) any
 }
 
-// TableColumnStyle describes the style of TableView columns.
-// To set column styles, you must either implement the TableColumnStyle interface in the table adapter
+// TableColumnStyle describes the style of [TableView] columns.
+//
+// To set column styles, you must either implement the [TableColumnStyle] interface in the table adapter
 // or assign its separate implementation to the "column-style" property.
 type TableColumnStyle interface {
+	// ColumnStyle returns a map of properties which describe the style of the column
 	ColumnStyle(column int) Params
 }
 
-// TableRowStyle describes the style of TableView rows.
-// To set row styles, you must either implement the TableRowStyle interface in the table adapter
+// TableRowStyle describes the style of [TableView] rows.
+//
+// To set row styles, you must either implement the [TableRowStyle] interface in the table adapter
 // or assign its separate implementation to the "row-style" property.
 type TableRowStyle interface {
+	// RowStyle returns a map of properties which describe the style of the row
 	RowStyle(row int) Params
 }
 
-// TableCellStyle describes the style of TableView cells.
-// To set row cells, you must either implement the TableCellStyle interface in the table adapter
+// TableCellStyle describes the style of [TableView] cells.
+//
+// To set row cells, you must either implement the [TableCellStyle] interface in the table adapter
 // or assign its separate implementation to the "cell-style" property.
 type TableCellStyle interface {
+	// CellStyle returns a map of properties which describe the style of the cell
 	CellStyle(row, column int) Params
 }
 
-// TableAllowCellSelection determines whether TableView cell selection is allowed.
+// TableAllowCellSelection determines whether [TableView] cell selection is allowed.
+//
 // It is only used if the "selection-mode" property is set to CellSelection (1).
+//
 // To set cell selection allowing, you must either implement the TableAllowCellSelection interface
 // in the table adapter or assign its separate implementation to the "allow-selection" property.
 type TableAllowCellSelection interface {
+	// AllowCellSelection returns "true" if we allow the user to select particular cell at specific rows and columns
 	AllowCellSelection(row, column int) bool
 }
 
-// TableAllowRowSelection determines whether TableView row selection is allowed.
+// TableAllowRowSelection determines whether [TableView] row selection is allowed.
+//
 // It is only used if the "selection-mode" property is set to RowSelection (2).
+//
 // To set row selection allowing, you must either implement the TableAllowRowSelection interface
 // in the table adapter or assign its separate implementation to the "allow-selection" property.
 type TableAllowRowSelection interface {
+	// AllowRowSelection returns "true" if we allow the user to select particular row in the table
 	AllowRowSelection(row int) bool
 }
 
-// SimpleTableAdapter is implementation of TableAdapter where the content
+// SimpleTableAdapter is implementation of [TableAdapter] where the content
 // defines as [][]any.
+//
 // When you assign [][]any value to the "content" property, it is converted to SimpleTableAdapter
 type SimpleTableAdapter interface {
 	TableAdapter
@@ -71,7 +84,7 @@ type simpleTableAdapter struct {
 	columnCount int
 }
 
-// TextTableAdapter is implementation of TableAdapter where the content
+// TextTableAdapter is implementation of [TableAdapter] where the content
 // defines as [][]string.
 // When you assign [][]string value to the "content" property, it is converted to TextTableAdapter
 type TextTableAdapter interface {
@@ -251,78 +264,3 @@ func (style *simpleTableLineStyle) RowStyle(row int) Params {
 	}
 	return nil
 }
-
-func (table *tableViewData) setLineStyle(tag string, value any) bool {
-	switch value := value.(type) {
-	case []Params:
-		if len(value) > 0 {
-			style := new(simpleTableLineStyle)
-			style.params = value
-			table.properties[tag] = style
-		} else {
-			delete(table.properties, tag)
-		}
-
-	case DataNode:
-		if params := value.ArrayAsParams(); len(params) > 0 {
-			style := new(simpleTableLineStyle)
-			style.params = params
-			table.properties[tag] = style
-		} else {
-			delete(table.properties, tag)
-		}
-
-	default:
-		return false
-	}
-	return true
-}
-
-func (table *tableViewData) setRowStyle(value any) bool {
-	switch value := value.(type) {
-	case TableRowStyle:
-		table.properties[RowStyle] = value
-	}
-	return table.setLineStyle(RowStyle, value)
-}
-
-func (table *tableViewData) getRowStyle() TableRowStyle {
-	for _, tag := range []string{RowStyle, Content} {
-		if value := table.getRaw(tag); value != nil {
-			if style, ok := value.(TableRowStyle); ok {
-				return style
-			}
-		}
-	}
-	return nil
-}
-
-func (table *tableViewData) setColumnStyle(value any) bool {
-	switch value := value.(type) {
-	case TableColumnStyle:
-		table.properties[ColumnStyle] = value
-	}
-	return table.setLineStyle(ColumnStyle, value)
-}
-
-func (table *tableViewData) getColumnStyle() TableColumnStyle {
-	for _, tag := range []string{ColumnStyle, Content} {
-		if value := table.getRaw(tag); value != nil {
-			if style, ok := value.(TableColumnStyle); ok {
-				return style
-			}
-		}
-	}
-	return nil
-}
-
-func (table *tableViewData) getCellStyle() TableCellStyle {
-	for _, tag := range []string{CellStyle, Content} {
-		if value := table.getRaw(tag); value != nil {
-			if style, ok := value.(TableCellStyle); ok {
-				return style
-			}
-		}
-	}
-	return nil
-}

tableViewUtils.go

@@ -1,17 +1,19 @@
 package rui
 
-import "strings"
-
-func (cell *tableCellView) Set(tag string, value any) bool {
-	return cell.set(strings.ToLower(tag), value)
+func newTableCellView(session Session) *tableCellView {
+	view := new(tableCellView)
+	view.init(session)
+	return view
 }
 
-func (cell *tableCellView) set(tag string, value any) bool {
-	switch tag {
-	case VerticalAlign:
-		tag = TableVerticalAlign
+func (cell *tableCellView) init(session Session) {
+	cell.viewData.init(session)
+	cell.normalize = func(tag PropertyName) PropertyName {
+		if tag == VerticalAlign {
+			return TableVerticalAlign
+		}
+		return tag
 	}
-	return cell.viewData.set(tag, value)
 }
 
 func (cell *tableCellView) cssStyle(self View, builder cssBuilder) {
@@ -26,13 +28,11 @@ func (cell *tableCellView) cssStyle(self View, builder cssBuilder) {
 // GetTableContent returns a TableAdapter which defines the TableView content.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetTableContent(view View, subviewID ...string) TableAdapter {
-	if len(subviewID) > 0 && subviewID[0] != "" {
-		view = ViewByID(view, subviewID[0])
-	}
-
-	if view != nil {
-		if tableView, ok := view.(TableView); ok {
-			return tableView.content()
+	if view = getSubview(view, subviewID); view != nil {
+		if content := view.getRaw(Content); content != nil {
+			if adapter, ok := content.(TableAdapter); ok {
+				return adapter
+			}
 		}
 	}
 
@@ -42,13 +42,13 @@ func GetTableContent(view View, subviewID ...string) TableAdapter {
 // GetTableRowStyle returns a TableRowStyle which defines styles of TableView rows.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetTableRowStyle(view View, subviewID ...string) TableRowStyle {
-	if len(subviewID) > 0 && subviewID[0] != "" {
-		view = ViewByID(view, subviewID[0])
-	}
-
-	if view != nil {
-		if tableView, ok := view.(TableView); ok {
-			return tableView.getRowStyle()
+	if view = getSubview(view, subviewID); view != nil {
+		for _, tag := range []PropertyName{RowStyle, Content} {
+			if value := view.getRaw(tag); value != nil {
+				if style, ok := value.(TableRowStyle); ok {
+					return style
+				}
+			}
 		}
 	}
 
@@ -58,13 +58,13 @@ func GetTableRowStyle(view View, subviewID ...string) TableRowStyle {
 // GetTableColumnStyle returns a TableColumnStyle which defines styles of TableView columns.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetTableColumnStyle(view View, subviewID ...string) TableColumnStyle {
-	if len(subviewID) > 0 && subviewID[0] != "" {
-		view = ViewByID(view, subviewID[0])
-	}
-
-	if view != nil {
-		if tableView, ok := view.(TableView); ok {
-			return tableView.getColumnStyle()
+	if view = getSubview(view, subviewID); view != nil {
+		for _, tag := range []PropertyName{ColumnStyle, Content} {
+			if value := view.getRaw(tag); value != nil {
+				if style, ok := value.(TableColumnStyle); ok {
+					return style
+				}
+			}
 		}
 	}
 
@@ -74,14 +74,15 @@ func GetTableColumnStyle(view View, subviewID ...string) TableColumnStyle {
 // GetTableCellStyle returns a TableCellStyle which defines styles of TableView cells.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetTableCellStyle(view View, subviewID ...string) TableCellStyle {
-	if len(subviewID) > 0 && subviewID[0] != "" {
-		view = ViewByID(view, subviewID[0])
-	}
-
-	if view != nil {
-		if tableView, ok := view.(TableView); ok {
-			return tableView.getCellStyle()
+	if view = getSubview(view, subviewID); view != nil {
+		for _, tag := range []PropertyName{CellStyle, Content} {
+			if value := view.getRaw(tag); value != nil {
+				if style, ok := value.(TableCellStyle); ok {
+					return style
+				}
+			}
 		}
+		return nil
 	}
 
 	return nil
@@ -119,15 +120,9 @@ func GetTableFootHeight(view View, subviewID ...string) int {
 // If the selection mode is RowSelection (2) then the returned column index is less than 0.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetTableCurrent(view View, subviewID ...string) CellIndex {
-	if len(subviewID) > 0 && subviewID[0] != "" {
-		view = ViewByID(view, subviewID[0])
-	}
-
-	if view != nil {
+	if view = getSubview(view, subviewID); view != nil {
 		if selectionMode := GetTableSelectionMode(view); selectionMode != NoneSelection {
-			if tableView, ok := view.(TableView); ok {
-				return tableView.getCurrent()
-			}
+			return tableViewCurrent(view)
 		}
 	}
 	return CellIndex{Row: -1, Column: -1}
@@ -137,84 +132,50 @@ func GetTableCurrent(view View, subviewID ...string) CellIndex {
 // If there are no listeners then the empty list is returned.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetTableCellClickedListeners(view View, subviewID ...string) []func(TableView, int, int) {
-	if len(subviewID) > 0 && subviewID[0] != "" {
-		view = ViewByID(view, subviewID[0])
-	}
-	if view != nil {
-		if value := view.Get(TableCellClickedEvent); value != nil {
-			if result, ok := value.([]func(TableView, int, int)); ok {
-				return result
-			}
-		}
-	}
-	return []func(TableView, int, int){}
+	return getTwoArgEventListeners[TableView, int](view, subviewID, TableCellClickedEvent)
 }
 
 // GetTableCellSelectedListeners returns listeners of event which occurs when a table cell becomes selected.
 // If there are no listeners then the empty list is returned.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetTableCellSelectedListeners(view View, subviewID ...string) []func(TableView, int, int) {
-	if len(subviewID) > 0 && subviewID[0] != "" {
-		view = ViewByID(view, subviewID[0])
-	}
-	if view != nil {
-		if value := view.Get(TableCellSelectedEvent); value != nil {
-			if result, ok := value.([]func(TableView, int, int)); ok {
-				return result
-			}
-		}
-	}
-	return []func(TableView, int, int){}
+	return getTwoArgEventListeners[TableView, int](view, subviewID, TableCellSelectedEvent)
 }
 
 // GetTableRowClickedListeners returns listeners of event which occurs when the user clicks on a table row.
 // If there are no listeners then the empty list is returned.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetTableRowClickedListeners(view View, subviewID ...string) []func(TableView, int) {
-	return getEventListeners[TableView, int](view, subviewID, TableRowClickedEvent)
+	return getOneArgEventListeners[TableView, int](view, subviewID, TableRowClickedEvent)
 }
 
 // GetTableRowSelectedListeners returns listeners of event which occurs when a table row becomes selected.
 // If there are no listeners then the empty list is returned.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetTableRowSelectedListeners(view View, subviewID ...string) []func(TableView, int) {
-	return getEventListeners[TableView, int](view, subviewID, TableRowSelectedEvent)
+	return getOneArgEventListeners[TableView, int](view, subviewID, TableRowSelectedEvent)
 }
 
 // ReloadTableViewData updates TableView
 // If the second argument (subviewID) is not specified or it is "" then updates the first argument (TableView).
 func ReloadTableViewData(view View, subviewID ...string) bool {
-	var tableView TableView
-	if len(subviewID) > 0 && subviewID[0] != "" {
-		if tableView = TableViewByID(view, subviewID[0]); tableView == nil {
-			return false
-		}
-	} else {
-		var ok bool
-		if tableView, ok = view.(TableView); !ok {
-			return false
+	if view = getSubview(view, subviewID); view != nil {
+		if tableView, ok := view.(TableView); ok {
+			tableView.ReloadTableData()
+			return true
 		}
 	}
-
-	tableView.ReloadTableData()
-	return true
+	return false
 }
 
 // ReloadTableViewCell updates the given table cell.
 // If the last argument (subviewID) is not specified or it is "" then updates the cell of the first argument (TableView).
 func ReloadTableViewCell(row, column int, view View, subviewID ...string) bool {
-	var tableView TableView
-	if len(subviewID) > 0 && subviewID[0] != "" {
-		if tableView = TableViewByID(view, subviewID[0]); tableView == nil {
-			return false
-		}
-	} else {
-		var ok bool
-		if tableView, ok = view.(TableView); !ok {
-			return false
+	if view = getSubview(view, subviewID); view != nil {
+		if tableView, ok := view.(TableView); ok {
+			tableView.ReloadCell(row, column)
+			return true
 		}
 	}
-
-	tableView.ReloadCell(row, column)
-	return true
+	return false
 }

tabsLayout.go

@@ -5,47 +5,120 @@ import (
 	"strings"
 )
 
+// Constants for [TabsLayout] specific view and events
 const (
 	// CurrentTabChangedEvent is the constant for "current-tab-changed" property tag.
-	// The "current-tab-changed" event occurs when the new tab becomes active.
-	// The main listener format: func(TabsLayout, int, int), where
-	// the second argument is the index of the new active tab,
-	// the third argument is the index of the old active tab.
-	CurrentTabChangedEvent = "current-tab-changed"
+	//
+	// Used by TabsLayout.
+	// Occur when the new tab becomes active.
+	//
+	// General listener format:
+	//
+	//   func(tabsLayout rui.TabsLayout, newTab, oldTab int)
+	//
+	// where:
+	//   - tabsLayout - Interface of a tabs layout which generated this event,
+	//   - newTab - Index of a new active tab,
+	//   - oldTab - Index of an old active tab.
+	//
+	// Allowed listener formats:
+	//
+	//  func(tabsLayout rui.TabsLayout, newTab int)
+	//  func(newTab, oldTab int)
+	//  func(newTab int)
+	//  func()
+	CurrentTabChangedEvent PropertyName = "current-tab-changed"
 
 	// Icon is the constant for "icon" property tag.
-	// The string "icon" property defines the icon name that is displayed in the tab.
-	Icon = "icon"
+	//
+	// Used by TabsLayout.
+	// Defines the icon name that is displayed in the tab. The property is set for the child view of TabsLayout.
+	//
+	// Supported types: string.
+	Icon PropertyName = "icon"
 
 	// TabCloseButton is the constant for "tab-close-button" property tag.
-	// The "tab-close-button" is the bool property. If it is "true" then a close button is displayed within the tab.
-	TabCloseButton = "tab-close-button"
+	//
+	// Used by TabsLayout.
+	// Controls whether to add close button to a tab(s). This property can be set separately for each child view or for tabs
+	// layout itself. Property set for child view takes precedence over the value set for tabs layout. Default value is
+	// false.
+	//
+	// Supported types: bool, int, string.
+	//
+	// Values:
+	//   - true, 1, "true", "yes", "on", "1" - Tab(s) has close button.
+	//   - false, 0, "false", "no", "off", "0" - No close button in tab(s).
+	TabCloseButton PropertyName = "tab-close-button"
 
 	// TabCloseEvent is the constant for "tab-close-event" property tag.
-	// The "tab-close-event" occurs when when the user clicks on the tab close button.
-	// The main listener format: func(TabsLayout, int), where the second argument is the index of the tab.
-	TabCloseEvent = "tab-close-event"
+	//
+	// Used by TabsLayout.
+	// Occurs when the user clicks on the tab close button.
+	//
+	// General listener format:
+	//
+	//  func(tabsLayout rui.TabsLayout, tab int)
+	//
+	// where:
+	//   - tabsLayout - Interface of a tabs layout which generated this event,
+	//   - tab - Index of the tab.
+	//
+	// Allowed listener formats:
+	//
+	//  func(tab int)
+	//  func(tabsLayout rui.TabsLayout)
+	//  func()
+	TabCloseEvent PropertyName = "tab-close-event"
 
-	// Tabs is the constant for the "tabs" property tag.
-	// The "tabs" is the int property that sets where the tabs are located.
-	// Valid values: TopTabs (0), BottomTabs (1), LeftTabs (2), RightTabs (3), LeftListTabs (4), RightListTabs (5), and HiddenTabs (6).
-	Tabs = "tabs"
+	// Tabs is the constant for "tabs" property tag.
+	//
+	// Used by TabsLayout.
+	// Sets where the tabs are located. Default value is "top".
+	//
+	// Supported types: int, string.
+	//
+	// Values:
+	//   - 0 (TopTabs) or "top" - Tabs on the top.
+	//   - 1 (BottomTabs) or "bottom" - Tabs on the bottom.
+	//   - 2 (LeftTabs) or "left" - Tabs on the left. Each tab is rotated 90° counterclockwise.
+	//   - 3 (RightTabs) or "right" - Tabs located on the right. Each tab is rotated 90° clockwise.
+	//   - 4 (LeftListTabs) or "left-list" - Tabs on the left. The tabs are displayed as a list.
+	//   - 5 (RightListTabs) or "right-list" - Tabs on the right. The tabs are displayed as a list.
+	//   - 6 (HiddenTabs) or "hidden" - Tabs are hidden.
+	Tabs PropertyName = "tabs"
 
-	// TabBarStyle is the constant for the "tab-bar-style" property tag.
-	// The "tab-bar-style" is the string property that sets the style for the display of the tab bar.
-	// The default value is "ruiTabBar".
-	TabBarStyle = "tab-bar-style"
+	// TabBarStyle is the constant for "tab-bar-style" property tag.
+	//
+	// Used by TabsLayout.
+	// Set the style for the display of the tab bar. The default value is "ruiTabBar".
+	//
+	// Supported types: string.
+	TabBarStyle PropertyName = "tab-bar-style"
 
-	// TabStyle is the constant for the "tab-style" property tag.
-	// The "tab-style" is the string property that sets the style for the display of the tab.
-	// The default value is "ruiTab" or "ruiVerticalTab".
-	TabStyle = "tab-style"
+	// TabStyle is the constant for "tab-style" property tag.
+	//
+	// Used by TabsLayout.
+	// Set the style for the display of the tab. The default value is "ruiTab" or "ruiVerticalTab".
+	//
+	// Supported types: string.
+	TabStyle PropertyName = "tab-style"
 
-	// CurrentTabStyle is the constant for the "current-tab-style" property tag.
-	// The "current-tab-style" is the string property that sets the style for the display of the current (selected) tab.
-	// The default value is "ruiCurrentTab" or "ruiCurrentVerticalTab".
-	CurrentTabStyle = "current-tab-style"
+	// CurrentTabStyle is the constant for "current-tab-style" property tag.
+	//
+	// Used by TabsLayout.
+	// Set the style for the display of the current(selected) tab. The default value is "ruiCurrentTab" or
+	// "ruiCurrentVerticalTab".
+	//
+	// Supported types: string.
+	CurrentTabStyle PropertyName = "current-tab-style"
 
+	inactiveTabStyle = "data-inactiveTabStyle"
+	activeTabStyle   = "data-activeTabStyle"
+)
+
+// Constants that are the values of the "tabs" property of a [TabsLayout]
+const (
 	// TopTabs - tabs of TabsLayout are on the top
 	TopTabs = 0
 	// BottomTabs - tabs of TabsLayout are on the bottom
@@ -60,12 +133,9 @@ const (
 	RightListTabs = 5
 	// HiddenTabs - tabs of TabsLayout are hidden
 	HiddenTabs = 6
-
-	inactiveTabStyle = "data-inactiveTabStyle"
-	activeTabStyle   = "data-activeTabStyle"
 )
 
-// TabsLayout - multi-tab container of View
+// TabsLayout represents a TabsLayout view
 type TabsLayout interface {
 	ViewsContainer
 	ListAdapter
@@ -73,8 +143,6 @@ type TabsLayout interface {
 
 type tabsLayoutData struct {
 	viewsContainerData
-	tabListener      []func(TabsLayout, int, int)
-	tabCloseListener []func(TabsLayout, int)
 }
 
 // NewTabsLayout create new TabsLayout object and return it
@@ -86,7 +154,8 @@ func NewTabsLayout(session Session, params Params) TabsLayout {
 }
 
 func newTabsLayout(session Session) View {
-	return NewTabsLayout(session, nil)
+	//return NewTabsLayout(session, nil)
+	return new(tabsLayoutData)
 }
 
 // Init initialize fields of ViewsContainer by default values
@@ -94,345 +163,229 @@ func (tabsLayout *tabsLayoutData) init(session Session) {
 	tabsLayout.viewsContainerData.init(session)
 	tabsLayout.tag = "TabsLayout"
 	tabsLayout.systemClass = "ruiTabsLayout"
-	tabsLayout.tabListener = []func(TabsLayout, int, int){}
-	tabsLayout.tabCloseListener = []func(TabsLayout, int){}
+	tabsLayout.set = tabsLayout.setFunc
+	tabsLayout.changed = tabsLayout.propertyChanged
 }
 
-func (tabsLayout *tabsLayoutData) String() string {
-	return getViewString(tabsLayout, nil)
-}
-
-func (tabsLayout *tabsLayoutData) currentItem(defaultValue int) int {
-	result, _ := intProperty(tabsLayout, Current, tabsLayout.session, defaultValue)
+func tabsLayoutCurrent(view View, defaultValue int) int {
+	result, _ := intProperty(view, Current, view.Session(), defaultValue)
 	return result
 }
 
-func (tabsLayout *tabsLayoutData) Get(tag string) any {
-	return tabsLayout.get(strings.ToLower(tag))
-}
-
-func (tabsLayout *tabsLayoutData) get(tag string) any {
+func (tabsLayout *tabsLayoutData) setFunc(tag PropertyName, value any) []PropertyName {
 	switch tag {
 	case CurrentTabChangedEvent:
-		return tabsLayout.tabListener
+		return setTwoArgEventListener[TabsLayout, int](tabsLayout, tag, value)
 
 	case TabCloseEvent:
-		return tabsLayout.tabCloseListener
-	}
-
-	return tabsLayout.viewsContainerData.get(tag)
-}
-
-func (tabsLayout *tabsLayoutData) Remove(tag string) {
-	tabsLayout.remove(strings.ToLower(tag))
-}
-
-func (tabsLayout *tabsLayoutData) remove(tag string) {
-	switch tag {
-	case CurrentTabChangedEvent:
-		if len(tabsLayout.tabListener) > 0 {
-			tabsLayout.tabListener = []func(TabsLayout, int, int){}
-			tabsLayout.propertyChangedEvent(tag)
-		}
-		return
-
-	case TabCloseEvent:
-		if len(tabsLayout.tabCloseListener) > 0 {
-			tabsLayout.tabCloseListener = []func(TabsLayout, int){}
-			tabsLayout.propertyChangedEvent(tag)
-		}
-		return
+		return setOneArgEventListener[TabsLayout, int](tabsLayout, tag, value)
 
 	case Current:
-		oldCurrent := tabsLayout.currentItem(0)
-		delete(tabsLayout.properties, Current)
-		if oldCurrent == 0 {
-			return
-		}
-		if tabsLayout.created {
-			tabsLayout.session.callFunc("activateTab", tabsLayout.htmlID(), 0)
-			for _, listener := range tabsLayout.tabListener {
-				listener(tabsLayout, 0, oldCurrent)
-			}
-		}
+		tabsLayout.setRaw("old-current", tabsLayoutCurrent(tabsLayout, -1))
 
-	case Tabs:
-		delete(tabsLayout.properties, Tabs)
-		if tabsLayout.created {
-			htmlID := tabsLayout.htmlID()
-			tabsLayout.session.updateProperty(htmlID, inactiveTabStyle, tabsLayout.inactiveTabStyle())
-			tabsLayout.session.updateProperty(htmlID, activeTabStyle, tabsLayout.activeTabStyle())
-			updateCSSStyle(htmlID, tabsLayout.session)
-			updateInnerHTML(htmlID, tabsLayout.session)
-		}
-
-	case TabStyle, CurrentTabStyle:
-		delete(tabsLayout.properties, tag)
-		if tabsLayout.created {
-			htmlID := tabsLayout.htmlID()
-			tabsLayout.session.updateProperty(htmlID, inactiveTabStyle, tabsLayout.inactiveTabStyle())
-			tabsLayout.session.updateProperty(htmlID, activeTabStyle, tabsLayout.activeTabStyle())
-			updateInnerHTML(htmlID, tabsLayout.session)
-		}
-
-	case TabCloseButton:
-		delete(tabsLayout.properties, tag)
-		if tabsLayout.created {
-			updateInnerHTML(tabsLayout.htmlID(), tabsLayout.session)
-		}
-
-	default:
-		tabsLayout.viewsContainerData.remove(tag)
-		return
-	}
-
-	tabsLayout.propertyChangedEvent(tag)
-}
-
-func (tabsLayout *tabsLayoutData) Set(tag string, value any) bool {
-	return tabsLayout.set(strings.ToLower(tag), value)
-}
-
-func (tabsLayout *tabsLayoutData) set(tag string, value any) bool {
-	if value == nil {
-		tabsLayout.remove(tag)
-		return true
-	}
-
-	switch tag {
-	case CurrentTabChangedEvent:
-		listeners := tabsLayout.valueToTabListeners(value)
-		if listeners == nil {
-			notCompatibleType(tag, value)
-			return false
-		}
-		tabsLayout.tabListener = listeners
-
-	case TabCloseEvent:
-		listeners, ok := valueToEventListeners[TabsLayout, int](value)
-		if !ok {
-			notCompatibleType(tag, value)
-			return false
-		} else if listeners == nil {
-			listeners = []func(TabsLayout, int){}
-		}
-		tabsLayout.tabCloseListener = listeners
-
-	case Current:
 		if current, ok := value.(int); ok && current < 0 {
-			tabsLayout.remove(Current)
-			return true
+			tabsLayout.setRaw(Current, nil)
+			return []PropertyName{tag}
 		}
 
-		oldCurrent := tabsLayout.currentItem(-1)
-		if !tabsLayout.setIntProperty(Current, value) {
-			return false
-		}
+		return setIntProperty(tabsLayout, Current, value)
 
-		current := tabsLayout.currentItem(0)
-		if oldCurrent == current {
-			return true
+	case TabStyle, CurrentTabStyle, TabBarStyle:
+		if text, ok := value.(string); ok {
+			return setStringPropertyValue(tabsLayout, tag, text)
 		}
-		if tabsLayout.created {
-			tabsLayout.session.callFunc("activateTab", tabsLayout.htmlID(), current)
-			for _, listener := range tabsLayout.tabListener {
+		notCompatibleType(tag, value)
+		return nil
+	}
+
+	return tabsLayout.viewsContainerData.setFunc(tag, value)
+}
+
+func (tabsLayout *tabsLayoutData) propertyChanged(tag PropertyName) {
+	switch tag {
+	case Current:
+		session := tabsLayout.Session()
+		current := GetCurrent(tabsLayout)
+		session.callFunc("activateTab", tabsLayout.htmlID(), current)
+
+		if listeners := getTwoArgEventListeners[TabsLayout, int](tabsLayout, nil, CurrentTabChangedEvent); len(listeners) > 0 {
+			oldCurrent, _ := intProperty(tabsLayout, "old-current", session, -1)
+			for _, listener := range listeners {
 				listener(tabsLayout, current, oldCurrent)
 			}
 		}
 
 	case Tabs:
-		if !tabsLayout.setEnumProperty(Tabs, value, enumProperties[Tabs].values) {
-			return false
-		}
-		if tabsLayout.created {
-			htmlID := tabsLayout.htmlID()
-			tabsLayout.session.updateProperty(htmlID, inactiveTabStyle, tabsLayout.inactiveTabStyle())
-			tabsLayout.session.updateProperty(htmlID, activeTabStyle, tabsLayout.activeTabStyle())
-			updateCSSStyle(htmlID, tabsLayout.session)
-			updateInnerHTML(htmlID, tabsLayout.session)
-		}
+		htmlID := tabsLayout.htmlID()
+		session := tabsLayout.Session()
+		session.updateProperty(htmlID, inactiveTabStyle, tabsLayoutInactiveTabStyle(tabsLayout))
+		session.updateProperty(htmlID, activeTabStyle, tabsLayoutActiveTabStyle(tabsLayout))
+		updateCSSStyle(htmlID, session)
+		updateInnerHTML(htmlID, session)
 
 	case TabStyle, CurrentTabStyle, TabBarStyle:
-		if text, ok := value.(string); ok {
-			if text == "" {
-				delete(tabsLayout.properties, tag)
-			} else {
-				tabsLayout.properties[tag] = text
-			}
-		} else {
-			notCompatibleType(tag, value)
-			return false
-		}
-
-		if tabsLayout.created {
-			htmlID := tabsLayout.htmlID()
-			tabsLayout.session.updateProperty(htmlID, inactiveTabStyle, tabsLayout.inactiveTabStyle())
-			tabsLayout.session.updateProperty(htmlID, activeTabStyle, tabsLayout.activeTabStyle())
-			updateInnerHTML(htmlID, tabsLayout.session)
-		}
+		htmlID := tabsLayout.htmlID()
+		session := tabsLayout.Session()
+		session.updateProperty(htmlID, inactiveTabStyle, tabsLayoutInactiveTabStyle(tabsLayout))
+		session.updateProperty(htmlID, activeTabStyle, tabsLayoutActiveTabStyle(tabsLayout))
+		updateInnerHTML(htmlID, session)
 
 	case TabCloseButton:
-		if !tabsLayout.setBoolProperty(tag, value) {
-			return false
-		}
-		if tabsLayout.created {
-			updateInnerHTML(tabsLayout.htmlID(), tabsLayout.session)
-		}
+		updateInnerHTML(tabsLayout.htmlID(), tabsLayout.Session())
 
 	default:
-		return tabsLayout.viewsContainerData.set(tag, value)
+		tabsLayout.viewsContainerData.propertyChanged(tag)
 	}
-
-	tabsLayout.propertyChangedEvent(tag)
-	return true
 }
 
-func (tabsLayout *tabsLayoutData) valueToTabListeners(value any) []func(TabsLayout, int, int) {
-	if value == nil {
-		return []func(TabsLayout, int, int){}
-	}
-
-	switch value := value.(type) {
-	case func(TabsLayout, int, int):
-		return []func(TabsLayout, int, int){value}
-
-	case func(TabsLayout, int):
-		fn := func(view TabsLayout, current, _ int) {
-			value(view, current)
+/*
+	func (tabsLayout *tabsLayoutData) valueToTabListeners(value any) []func(TabsLayout, int, int) {
+		if value == nil {
+			return []func(TabsLayout, int, int){}
 		}
-		return []func(TabsLayout, int, int){fn}
 
-	case func(TabsLayout):
-		fn := func(view TabsLayout, _, _ int) {
-			value(view)
-		}
-		return []func(TabsLayout, int, int){fn}
+		switch value := value.(type) {
+		case func(TabsLayout, int, int):
+			return []func(TabsLayout, int, int){value}
 
-	case func(int, int):
-		fn := func(_ TabsLayout, current, old int) {
-			value(current, old)
-		}
-		return []func(TabsLayout, int, int){fn}
-
-	case func(int):
-		fn := func(_ TabsLayout, current, _ int) {
-			value(current)
-		}
-		return []func(TabsLayout, int, int){fn}
-
-	case func():
-		fn := func(TabsLayout, int, int) {
-			value()
-		}
-		return []func(TabsLayout, int, int){fn}
-
-	case []func(TabsLayout, int, int):
-		return value
-
-	case []func(TabsLayout, int):
-		listeners := make([]func(TabsLayout, int, int), len(value))
-		for i, val := range value {
-			if val == nil {
-				return nil
+		case func(TabsLayout, int):
+			fn := func(view TabsLayout, current, _ int) {
+				value(view, current)
 			}
-			listeners[i] = func(view TabsLayout, current, _ int) {
-				val(view, current)
-			}
-		}
-		return listeners
+			return []func(TabsLayout, int, int){fn}
 
-	case []func(TabsLayout):
-		listeners := make([]func(TabsLayout, int, int), len(value))
-		for i, val := range value {
-			if val == nil {
-				return nil
+		case func(TabsLayout):
+			fn := func(view TabsLayout, _, _ int) {
+				value(view)
 			}
-			listeners[i] = func(view TabsLayout, _, _ int) {
-				val(view)
-			}
-		}
-		return listeners
+			return []func(TabsLayout, int, int){fn}
 
-	case []func(int, int):
-		listeners := make([]func(TabsLayout, int, int), len(value))
-		for i, val := range value {
-			if val == nil {
-				return nil
+		case func(int, int):
+			fn := func(_ TabsLayout, current, old int) {
+				value(current, old)
 			}
-			listeners[i] = func(_ TabsLayout, current, old int) {
-				val(current, old)
-			}
-		}
-		return listeners
+			return []func(TabsLayout, int, int){fn}
 
-	case []func(int):
-		listeners := make([]func(TabsLayout, int, int), len(value))
-		for i, val := range value {
-			if val == nil {
-				return nil
+		case func(int):
+			fn := func(_ TabsLayout, current, _ int) {
+				value(current)
 			}
-			listeners[i] = func(_ TabsLayout, current, _ int) {
-				val(current)
-			}
-		}
-		return listeners
+			return []func(TabsLayout, int, int){fn}
 
-	case []func():
-		listeners := make([]func(TabsLayout, int, int), len(value))
-		for i, val := range value {
-			if val == nil {
-				return nil
+		case func():
+			fn := func(TabsLayout, int, int) {
+				value()
 			}
-			listeners[i] = func(TabsLayout, int, int) {
-				val()
-			}
-		}
-		return listeners
+			return []func(TabsLayout, int, int){fn}
 
-	case []any:
-		listeners := make([]func(TabsLayout, int, int), len(value))
-		for i, val := range value {
-			if val == nil {
-				return nil
-			}
-			switch val := val.(type) {
-			case func(TabsLayout, int, int):
-				listeners[i] = val
+		case []func(TabsLayout, int, int):
+			return value
 
-			case func(TabsLayout, int):
+		case []func(TabsLayout, int):
+			listeners := make([]func(TabsLayout, int, int), len(value))
+			for i, val := range value {
+				if val == nil {
+					return nil
+				}
 				listeners[i] = func(view TabsLayout, current, _ int) {
 					val(view, current)
 				}
+			}
+			return listeners
 
-			case func(TabsLayout):
+		case []func(TabsLayout):
+			listeners := make([]func(TabsLayout, int, int), len(value))
+			for i, val := range value {
+				if val == nil {
+					return nil
+				}
 				listeners[i] = func(view TabsLayout, _, _ int) {
 					val(view)
 				}
+			}
+			return listeners
 
-			case func(int, int):
+		case []func(int, int):
+			listeners := make([]func(TabsLayout, int, int), len(value))
+			for i, val := range value {
+				if val == nil {
+					return nil
+				}
 				listeners[i] = func(_ TabsLayout, current, old int) {
 					val(current, old)
 				}
+			}
+			return listeners
 
-			case func(int):
+		case []func(int):
+			listeners := make([]func(TabsLayout, int, int), len(value))
+			for i, val := range value {
+				if val == nil {
+					return nil
+				}
 				listeners[i] = func(_ TabsLayout, current, _ int) {
 					val(current)
 				}
+			}
+			return listeners
 
-			case func():
+		case []func():
+			listeners := make([]func(TabsLayout, int, int), len(value))
+			for i, val := range value {
+				if val == nil {
+					return nil
+				}
 				listeners[i] = func(TabsLayout, int, int) {
 					val()
 				}
-
-			default:
-				return nil
 			}
-		}
-		return listeners
-	}
+			return listeners
 
-	return nil
-}
+		case []any:
+			listeners := make([]func(TabsLayout, int, int), len(value))
+			for i, val := range value {
+				if val == nil {
+					return nil
+				}
+				switch val := val.(type) {
+				case func(TabsLayout, int, int):
+					listeners[i] = val
+
+				case func(TabsLayout, int):
+					listeners[i] = func(view TabsLayout, current, _ int) {
+						val(view, current)
+					}
+
+				case func(TabsLayout):
+					listeners[i] = func(view TabsLayout, _, _ int) {
+						val(view)
+					}
+
+				case func(int, int):
+					listeners[i] = func(_ TabsLayout, current, old int) {
+						val(current, old)
+					}
+
+				case func(int):
+					listeners[i] = func(_ TabsLayout, current, _ int) {
+						val(current)
+					}
+
+				case func():
+					listeners[i] = func(TabsLayout, int, int) {
+						val()
+					}
+
+				default:
+					return nil
+				}
+			}
+			return listeners
+		}
+
+		return nil
+	}
+*/
 
 func (tabsLayout *tabsLayoutData) tabsLocation() int {
 	tabs, _ := enumProperty(tabsLayout, Tabs, tabsLayout.session, 0)
@@ -453,36 +406,42 @@ func (tabsLayout *tabsLayoutData) tabBarStyle() string {
 	return "ruiTabBar"
 }
 
-func (tabsLayout *tabsLayoutData) inactiveTabStyle() string {
-	if style, ok := stringProperty(tabsLayout, TabStyle, tabsLayout.session); ok {
+func tabsLayoutInactiveTabStyle(view View) string {
+	session := view.Session()
+	if style, ok := stringProperty(view, TabStyle, session); ok {
 		return style
 	}
-	if value := valueFromStyle(tabsLayout, TabStyle); value != nil {
+	if value := valueFromStyle(view, TabStyle); value != nil {
 		if style, ok := value.(string); ok {
-			if style, ok = tabsLayout.session.resolveConstants(style); ok {
+			if style, ok = session.resolveConstants(style); ok {
 				return style
 			}
 		}
 	}
-	switch tabsLayout.tabsLocation() {
+
+	tabs, _ := enumProperty(view, Tabs, session, 0)
+	switch tabs {
 	case LeftTabs, RightTabs:
 		return "ruiVerticalTab"
 	}
 	return "ruiTab"
 }
 
-func (tabsLayout *tabsLayoutData) activeTabStyle() string {
-	if style, ok := stringProperty(tabsLayout, CurrentTabStyle, tabsLayout.session); ok {
+func tabsLayoutActiveTabStyle(view View) string {
+	session := view.Session()
+	if style, ok := stringProperty(view, CurrentTabStyle, session); ok {
 		return style
 	}
-	if value := valueFromStyle(tabsLayout, CurrentTabStyle); value != nil {
+	if value := valueFromStyle(view, CurrentTabStyle); value != nil {
 		if style, ok := value.(string); ok {
-			if style, ok = tabsLayout.session.resolveConstants(style); ok {
+			if style, ok = session.resolveConstants(style); ok {
 				return style
 			}
 		}
 	}
-	switch tabsLayout.tabsLocation() {
+
+	tabs, _ := enumProperty(view, Tabs, session, 0)
+	switch tabs {
 	case LeftTabs, RightTabs:
 		return "ruiCurrentVerticalTab"
 	}
@@ -544,7 +503,7 @@ func (tabsLayout *tabsLayoutData) ListItem(index int, session Session) View {
 			Column:  2,
 			Content: "✕",
 			ClickEvent: func() {
-				for _, listener := range tabsLayout.tabCloseListener {
+				for _, listener := range getOneArgEventListeners[TabsLayout, int](tabsLayout, nil, TabCloseEvent) {
 					listener(tabsLayout, index)
 				}
 			},
@@ -566,7 +525,7 @@ func (tabsLayout *tabsLayoutData) IsListItemEnabled(index int) bool {
 	return true
 }
 
-func (tabsLayout *tabsLayoutData) updateTitle(view View, tag string) {
+func (tabsLayout *tabsLayoutData) updateTitle(view View, tag PropertyName) {
 	session := tabsLayout.session
 	title, _ := stringProperty(view, Title, session)
 	if !GetNotTranslate(tabsLayout) {
@@ -575,13 +534,13 @@ func (tabsLayout *tabsLayoutData) updateTitle(view View, tag string) {
 	session.updateInnerHTML(view.htmlID()+"-title", title)
 }
 
-func (tabsLayout *tabsLayoutData) updateIcon(view View, tag string) {
+func (tabsLayout *tabsLayoutData) updateIcon(view View, tag PropertyName) {
 	session := tabsLayout.session
 	icon, _ := stringProperty(view, Icon, session)
 	session.updateProperty(view.htmlID()+"-icon", "src", icon)
 }
 
-func (tabsLayout *tabsLayoutData) updateTabCloseButton(view View, tag string) {
+func (tabsLayout *tabsLayoutData) updateTabCloseButton(view View, tag PropertyName) {
 	updateInnerHTML(tabsLayout.htmlID(), tabsLayout.session)
 }
 
@@ -596,11 +555,8 @@ func (tabsLayout *tabsLayoutData) Append(view View) {
 		view.SetChangeListener(Icon, tabsLayout.updateIcon)
 		view.SetChangeListener(TabCloseButton, tabsLayout.updateTabCloseButton)
 		if len(tabsLayout.views) == 1 {
-			tabsLayout.properties[Current] = 0
-			for _, listener := range tabsLayout.tabListener {
-				listener(tabsLayout, 0, -1)
-			}
-			defer tabsLayout.propertyChangedEvent(Current)
+			tabsLayout.setRaw(Current, nil)
+			tabsLayout.Set(Current, 0)
 		}
 	}
 }
@@ -611,9 +567,9 @@ func (tabsLayout *tabsLayoutData) Insert(view View, index int) {
 		tabsLayout.views = []View{}
 	}
 	if view != nil {
-		if current := tabsLayout.currentItem(0); current >= index {
-			tabsLayout.properties[Current] = current + 1
-			defer tabsLayout.propertyChangedEvent(Current)
+		if current := GetCurrent(tabsLayout); current >= index {
+			tabsLayout.setRaw(Current, current+1)
+			defer tabsLayout.currentChanged(current+1, current)
 		}
 		tabsLayout.viewsContainerData.Insert(view, index)
 		view.SetChangeListener(Title, tabsLayout.updateTitle)
@@ -622,61 +578,95 @@ func (tabsLayout *tabsLayoutData) Insert(view View, index int) {
 	}
 }
 
+func (tabsLayout *tabsLayoutData) currentChanged(newCurrent, oldCurrent int) {
+	for _, listener := range getTwoArgEventListeners[TabsLayout, int](tabsLayout, nil, CurrentTabChangedEvent) {
+		listener(tabsLayout, newCurrent, oldCurrent)
+	}
+	if listener, ok := tabsLayout.changeListener[Current]; ok {
+		listener(tabsLayout, Current)
+	}
+}
+
 // Remove removes view from list and return it
 func (tabsLayout *tabsLayoutData) RemoveView(index int) View {
-	if tabsLayout.views == nil {
-		tabsLayout.views = []View{}
+
+	if index < 0 || index >= len(tabsLayout.views) {
 		return nil
 	}
 
-	count := len(tabsLayout.views)
-	if index < 0 || index >= count {
-		return nil
+	oldCurrent := GetCurrent(tabsLayout)
+	newCurrent := oldCurrent
+	if index < oldCurrent || (index == oldCurrent && oldCurrent > 0) {
+		newCurrent--
 	}
 
-	view := tabsLayout.views[index]
-	view.setParentID("")
-	view.SetChangeListener(Title, nil)
-	view.SetChangeListener(Icon, nil)
-	view.SetChangeListener(TabCloseButton, nil)
+	if view := tabsLayout.viewsContainerData.RemoveView(index); view != nil {
+		view.SetChangeListener(Title, nil)
+		view.SetChangeListener(Icon, nil)
+		view.SetChangeListener(TabCloseButton, nil)
 
-	current := tabsLayout.currentItem(0)
-	if index < current || (index == current && current > 0) {
-		current--
+		if newCurrent != oldCurrent {
+			tabsLayout.setRaw(Current, newCurrent)
+			tabsLayout.currentChanged(newCurrent, oldCurrent)
+		}
 	}
+	return nil
 
-	if len(tabsLayout.views) == 1 {
-		tabsLayout.views = []View{}
-		current = -1
-	} else if index == 0 {
-		tabsLayout.views = tabsLayout.views[1:]
-	} else if index == count-1 {
-		tabsLayout.views = tabsLayout.views[:index]
-	} else {
-		tabsLayout.views = append(tabsLayout.views[:index], tabsLayout.views[index+1:]...)
-	}
+	/*
+		if tabsLayout.views == nil {
+			tabsLayout.views = []View{}
+			return nil
+		}
 
-	updateInnerHTML(tabsLayout.parentHTMLID(), tabsLayout.session)
-	tabsLayout.propertyChangedEvent(Content)
+		count := len(tabsLayout.views)
+		if index < 0 || index >= count {
+			return nil
+		}
 
-	delete(tabsLayout.properties, Current)
-	tabsLayout.set(Current, current)
-	return view
+		view := tabsLayout.views[index]
+		view.setParentID("")
+		view.SetChangeListener(Title, nil)
+		view.SetChangeListener(Icon, nil)
+		view.SetChangeListener(TabCloseButton, nil)
+
+		current := GetCurrent(tabsLayout)
+		if index < current || (index == current && current > 0) {
+			current--
+		}
+
+		if len(tabsLayout.views) == 1 {
+			tabsLayout.views = []View{}
+			current = -1
+		} else if index == 0 {
+			tabsLayout.views = tabsLayout.views[1:]
+		} else if index == count-1 {
+			tabsLayout.views = tabsLayout.views[:index]
+		} else {
+			tabsLayout.views = append(tabsLayout.views[:index], tabsLayout.views[index+1:]...)
+		}
+
+		updateInnerHTML(tabsLayout.parentHTMLID(), tabsLayout.session)
+		tabsLayout.propertyChangedEvent(Content)
+
+		delete(tabsLayout.view, Current)
+		tabsLayout.Set(Current, current)
+		return view
+	*/
 }
 
 func (tabsLayout *tabsLayoutData) htmlProperties(self View, buffer *strings.Builder) {
 	tabsLayout.viewsContainerData.htmlProperties(self, buffer)
 	buffer.WriteString(` data-inactiveTabStyle="`)
-	buffer.WriteString(tabsLayout.inactiveTabStyle())
+	buffer.WriteString(tabsLayoutInactiveTabStyle(tabsLayout))
 	buffer.WriteString(`" data-activeTabStyle="`)
-	buffer.WriteString(tabsLayout.activeTabStyle())
+	buffer.WriteString(tabsLayoutActiveTabStyle(tabsLayout))
 	buffer.WriteString(`" data-current="`)
-	buffer.WriteString(strconv.Itoa(tabsLayout.currentItem(0)))
+	buffer.WriteString(strconv.Itoa(GetCurrent(tabsLayout)))
 	buffer.WriteRune('"')
 }
 
 func (tabsLayout *tabsLayoutData) cssStyle(self View, builder cssBuilder) {
-	tabsLayout.viewsContainerData.cssStyle(self, builder)
+	tabsLayout.viewData.cssStyle(self, builder)
 	switch tabsLayout.tabsLocation() {
 	case TopTabs:
 		builder.add(`grid-template-rows`, `auto 1fr`)
@@ -697,8 +687,7 @@ func (tabsLayout *tabsLayoutData) htmlSubviews(self View, buffer *strings.Builde
 		return
 	}
 
-	//viewCount := len(tabsLayout.views)
-	current := tabsLayout.currentItem(0)
+	current := GetCurrent(tabsLayout)
 	location := tabsLayout.tabsLocation()
 	tabsLayoutID := tabsLayout.htmlID()
 
@@ -730,8 +719,8 @@ func (tabsLayout *tabsLayoutData) htmlSubviews(self View, buffer *strings.Builde
 
 		buffer.WriteString(`">`)
 
-		inactiveStyle := tabsLayout.inactiveTabStyle()
-		activeStyle := tabsLayout.activeTabStyle()
+		inactiveStyle := tabsLayoutInactiveTabStyle(tabsLayout)
+		activeStyle := tabsLayoutActiveTabStyle(tabsLayout)
 
 		notTranslate := GetNotTranslate(tabsLayout)
 		closeButton, _ := boolProperty(tabsLayout, TabCloseButton, tabsLayout.session)
@@ -859,40 +848,38 @@ func (tabsLayout *tabsLayoutData) htmlSubviews(self View, buffer *strings.Builde
 		buffer.WriteString(`-page`)
 		buffer.WriteString(strconv.Itoa(n))
 
+		if current != n {
+			buffer.WriteString(`" style="display: grid; align-items: stretch; justify-items: stretch; visibility: hidden; `)
+		} else {
+			buffer.WriteString(`" style="display: grid; align-items: stretch; justify-items: stretch; `)
+		}
+
 		switch location {
 		case LeftTabs, LeftListTabs:
-			buffer.WriteString(`" style="position: relative; grid-row-start: 1; grid-row-end: 2; grid-column-start: 2; grid-column-end: 3;`)
+			buffer.WriteString(`grid-row-start: 1; grid-row-end: 2; grid-column-start: 2; grid-column-end: 3;">`)
 
 		case TopTabs:
-			buffer.WriteString(`" style="position: relative; grid-row-start: 2; grid-row-end: 3; grid-column-start: 1; grid-column-end: 2;`)
+			buffer.WriteString(`grid-row-start: 2; grid-row-end: 3; grid-column-start: 1; grid-column-end: 2;">`)
 
 		default:
-			buffer.WriteString(`" style="position: relative; grid-row-start: 1; grid-row-end: 2; grid-column-start: 1; grid-column-end: 2;`)
+			buffer.WriteString(`grid-row-start: 1; grid-row-end: 2; grid-column-start: 1; grid-column-end: 2;">`)
 		}
 
-		if current != n {
-			buffer.WriteString(` display: none;`)
-		}
-		buffer.WriteString(`">`)
-
-		view.addToCSSStyle(map[string]string{`position`: `absolute`, `left`: `0`, `right`: `0`, `top`: `0`, `bottom`: `0`})
-		viewHTML(tabsLayout.views[n], buffer)
+		viewHTML(view, buffer, "")
 		buffer.WriteString(`</div>`)
 	}
 }
 
-func (tabsLayout *tabsLayoutData) handleCommand(self View, command string, data DataObject) bool {
+func (tabsLayout *tabsLayoutData) handleCommand(self View, command PropertyName, data DataObject) bool {
 	switch command {
 	case "tabClick":
 		if numberText, ok := data.PropertyValue("number"); ok {
 			if number, err := strconv.Atoi(numberText); err == nil {
-				current := tabsLayout.currentItem(0)
+				current := GetCurrent(tabsLayout)
 				if current != number {
-					tabsLayout.properties[Current] = number
-					for _, listener := range tabsLayout.tabListener {
-						listener(tabsLayout, number, current)
-					}
-					tabsLayout.propertyChangedEvent(Current)
+					tabsLayout.setRaw(Current, number)
+
+					tabsLayout.currentChanged(number, current)
 				}
 			}
 		}
@@ -901,7 +888,7 @@ func (tabsLayout *tabsLayoutData) handleCommand(self View, command string, data
 	case "tabCloseClick":
 		if numberText, ok := data.PropertyValue("number"); ok {
 			if number, err := strconv.Atoi(numberText); err == nil {
-				for _, listener := range tabsLayout.tabCloseListener {
+				for _, listener := range getOneArgEventListeners[TabsLayout, int](tabsLayout, nil, TabCloseEvent) {
 					listener(tabsLayout, number)
 				}
 			}

textView.go

@@ -5,7 +5,7 @@ import (
 	"strings"
 )
 
-// TextView - text View
+// TextView represents a TextView view
 type TextView interface {
 	View
 }
@@ -23,116 +23,79 @@ func NewTextView(session Session, params Params) TextView {
 }
 
 func newTextView(session Session) View {
-	return NewTextView(session, nil)
+	return new(textViewData)
 }
 
 // Init initialize fields of TextView by default values
 func (textView *textViewData) init(session Session) {
 	textView.viewData.init(session)
 	textView.tag = "TextView"
+	textView.set = textView.setFunc
+	textView.changed = textView.propertyChanged
 }
 
-func (textView *textViewData) String() string {
-	return getViewString(textView, nil)
-}
+func (textView *textViewData) propertyChanged(tag PropertyName) {
+	switch tag {
+	case Text:
+		updateInnerHTML(textView.htmlID(), textView.Session())
 
-func (textView *textViewData) Get(tag string) any {
-	return textView.get(strings.ToLower(tag))
-}
-
-func (textView *textViewData) Remove(tag string) {
-	textView.remove(strings.ToLower(tag))
-}
-
-func (textView *textViewData) remove(tag string) {
-	textView.viewData.remove(tag)
-	if textView.created {
-		switch tag {
-		case Text:
-			updateInnerHTML(textView.htmlID(), textView.session)
-
-		case TextOverflow:
-			textView.textOverflowUpdated()
+	case TextOverflow:
+		session := textView.Session()
+		if n, ok := enumProperty(textView, TextOverflow, session, 0); ok {
+			values := enumProperties[TextOverflow].cssValues
+			if n >= 0 && n < len(values) {
+				session.updateCSSProperty(textView.htmlID(), string(TextOverflow), values[n])
+				return
+			}
 		}
+		session.updateCSSProperty(textView.htmlID(), string(TextOverflow), "")
+
+	case NotTranslate:
+		updateInnerHTML(textView.htmlID(), textView.Session())
+
+	default:
+		textView.viewData.propertyChanged(tag)
 	}
 }
 
-func (textView *textViewData) Set(tag string, value any) bool {
-	return textView.set(strings.ToLower(tag), value)
-}
-
-func (textView *textViewData) set(tag string, value any) bool {
+func (textView *textViewData) setFunc(tag PropertyName, value any) []PropertyName {
 	switch tag {
 	case Text:
 		switch value := value.(type) {
 		case string:
-			textView.properties[Text] = value
+			textView.setRaw(Text, value)
 
 		case fmt.Stringer:
-			textView.properties[Text] = value.String()
+			textView.setRaw(Text, value.String())
 
 		case float32:
-			textView.properties[Text] = fmt.Sprintf("%g", float64(value))
+			textView.setRaw(Text, fmt.Sprintf("%g", float64(value)))
 
 		case float64:
-			textView.properties[Text] = fmt.Sprintf("%g", value)
+			textView.setRaw(Text, fmt.Sprintf("%g", value))
 
 		case []rune:
-			textView.properties[Text] = string(value)
+			textView.setRaw(Text, string(value))
 
 		case bool:
 			if value {
-				textView.properties[Text] = "true"
+				textView.setRaw(Text, "true")
 			} else {
-				textView.properties[Text] = "false"
+				textView.setRaw(Text, "false")
 			}
 
 		default:
 			if n, ok := isInt(value); ok {
-				textView.properties[Text] = fmt.Sprintf("%d", n)
+				textView.setRaw(Text, fmt.Sprintf("%d", n))
 			} else {
 				notCompatibleType(tag, value)
-				return false
+				return nil
 			}
 		}
-		if textView.created {
-			updateInnerHTML(textView.htmlID(), textView.session)
-		}
-
-	case TextOverflow:
-		if !textView.viewData.set(tag, value) {
-			return false
-		}
-		if textView.created {
-			textView.textOverflowUpdated()
-		}
-
-	case NotTranslate:
-		if !textView.viewData.set(tag, value) {
-			return false
-		}
-		if textView.created {
-			updateInnerHTML(textView.htmlID(), textView.Session())
-		}
-
-	default:
-		return textView.viewData.set(tag, value)
+		return []PropertyName{Text}
 	}
 
-	textView.propertyChangedEvent(tag)
-	return true
-}
-
-func (textView *textViewData) textOverflowUpdated() {
-	session := textView.Session()
-	if n, ok := enumProperty(textView, TextOverflow, session, 0); ok {
-		values := enumProperties[TextOverflow].cssValues
-		if n >= 0 && n < len(values) {
-			session.updateCSSProperty(textView.htmlID(), TextOverflow, values[n])
-			return
-		}
-	}
-	session.updateCSSProperty(textView.htmlID(), TextOverflow, "")
+	return textView.viewData.setFunc(tag, value)
 }
 
 func (textView *textViewData) htmlSubviews(self View, buffer *strings.Builder) {

theme.go

@@ -7,18 +7,34 @@ import (
 	"strings"
 )
 
+// Constants used as a values for [MediaStyleParams] member Orientation
 const (
-	DefaultMedia   = 0
-	PortraitMedia  = 1
+	// DefaultMedia means that style appliance will not be related to client's window orientation
+	DefaultMedia = 0
+
+	// PortraitMedia means that style apply on clients with portrait window orientation
+	PortraitMedia = 1
+
+	// PortraitMedia means that style apply on clients with landscape window orientation
 	LandscapeMedia = 2
 )
 
+// MediaStyleParams define rules when particular style will be applied
 type MediaStyleParams struct {
+	// Orientation for which particular style will be applied
 	Orientation int
-	MinWidth    int
-	MaxWidth    int
-	MinHeight   int
-	MaxHeight   int
+
+	// MinWidth for which particular style will be applied
+	MinWidth int
+
+	// MaxWidth for which particular style will be applied
+	MaxWidth int
+
+	// MinHeight for which particular style will be applied
+	MinHeight int
+
+	// MaxHeight for which particular style will be applied
+	MaxHeight int
 }
 
 type mediaStyle struct {
@@ -38,31 +54,65 @@ type theme struct {
 	mediaStyles    []mediaStyle
 }
 
+// Theme interface to describe application's theme
 type Theme interface {
 	fmt.Stringer
+
+	// Name returns a name of the theme
 	Name() string
+
+	// Constant returns normal and touch theme constant value with specific tag
 	Constant(tag string) (string, string)
+
+	// SetConstant sets a value for a constant
 	SetConstant(tag string, value, touchUIValue string)
+
 	// ConstantTags returns the list of all available constants
 	ConstantTags() []string
+
+	// Color returns normal and dark theme color constant value with specific tag
 	Color(tag string) (string, string)
+
+	// SetColor sets normal and dark theme color constant value with specific tag
 	SetColor(tag, color, darkUIColor string)
+
 	// ColorTags returns the list of all available color constants
 	ColorTags() []string
+
+	// Image returns normal and dark theme image constant value with specific tag
 	Image(tag string) (string, string)
+
+	// SetImage sets normal and dark theme image constant value with specific tag
 	SetImage(tag, image, darkUIImage string)
+
 	// ImageConstantTags returns the list of all available image constants
 	ImageConstantTags() []string
+
+	// Style returns view style by its tag
 	Style(tag string) ViewStyle
+
+	// SetStyle sets style for a tag
 	SetStyle(tag string, style ViewStyle)
+
+	// RemoveStyle removes style with provided tag
 	RemoveStyle(tag string)
+
+	// MediaStyle returns media style which correspond to provided media style parameters
 	MediaStyle(tag string, params MediaStyleParams) ViewStyle
+
+	// SetMediaStyle sets media style with provided media style parameters and a tag
 	SetMediaStyle(tag string, params MediaStyleParams, style ViewStyle)
+
+	// StyleTags returns all tags which describe a style
 	StyleTags() []string
+
+	// MediaStyles returns all media style settings which correspond to a style tag
 	MediaStyles(tag string) []struct {
 		Selectors string
 		Params    MediaStyleParams
 	}
+
+	// Append theme to a list of themes
 	Append(anotherTheme Theme)
 
 	constant(tag string, touchUI bool) string
@@ -196,6 +246,7 @@ func parseMediaRule(text string) (mediaStyle, bool) {
 
 var defaultTheme = NewTheme("")
 
+// NewTheme creates a new theme with specific name and return its interface.
 func NewTheme(name string) Theme {
 	result := new(theme)
 	result.init()
@@ -203,6 +254,7 @@ func NewTheme(name string) Theme {
 	return result
 }
 
+// CreateThemeFromText creates a new theme from text and return its interface on success.
 func CreateThemeFromText(text string) (Theme, bool) {
 	result := new(theme)
 	result.init()
@@ -589,7 +641,7 @@ func (theme *theme) cssText(session Session) string {
 	}
 
 	var builder cssStyleBuilder
-	builder.init()
+	builder.init(16)
 
 	styleList := func(styles map[string]ViewStyle) []string {
 		ruiStyles := []string{}
@@ -647,13 +699,13 @@ func (theme *theme) addText(themeText string) bool {
 			if node := obj.Property(i); node != nil {
 				switch node.Type() {
 				case ArrayNode:
-					params[node.Tag()] = node.ArrayElements()
+					params[PropertyName(node.Tag())] = node.ArrayElements()
 
 				case ObjectNode:
-					params[node.Tag()] = node.Object()
+					params[PropertyName(node.Tag())] = node.Object()
 
 				default:
-					params[node.Tag()] = node.Text()
+					params[PropertyName(node.Tag())] = node.Text()
 				}
 			}
 		}

timePicker.go

@@ -6,24 +6,101 @@ import (
 	"time"
 )
 
+// Constants for [TimePicker] specific properties and events.
 const (
-	TimeChangedEvent = "time-changed"
-	TimePickerMin    = "time-picker-min"
-	TimePickerMax    = "time-picker-max"
-	TimePickerStep   = "time-picker-step"
-	TimePickerValue  = "time-picker-value"
-	timeFormat       = "15:04:05"
+	// TimeChangedEvent is the constant for "time-changed" property tag.
+	//
+	// Used by TimePicker.
+	// Occur when current time of the time picker has been changed.
+	//
+	// General listener format:
+	//  func(picker rui.TimePicker, newTime time.Time, oldTime time.Time).
+	//
+	// where:
+	//   - picker - Interface of a time picker which generated this event,
+	//   - newTime - New time value,
+	//   - oldTime - Old time value.
+	//
+	// Allowed listener formats:
+	//  func(picker rui.TimePicker, newTime time.Time),
+	//  func(newTime time.Time, oldTime time.Time),
+	//  func(newTime time.Time),
+	//  func(picker rui.TimePicker),
+	//  func().
+	TimeChangedEvent PropertyName = "time-changed"
+
+	// TimePickerMin is the constant for "time-picker-min" property tag.
+	//
+	// Used by TimePicker.
+	// The minimum value of the time.
+	//
+	// Supported types: time.Time, string.
+	//
+	// Internal type is time.Time, other types converted to it during assignment.
+	//
+	// Conversion rules:
+	// string - values of this type parsed and converted to time.Time. The following formats are supported:
+	//   - "HH:MM:SS" - "08:15:00".
+	//   - "HH:MM:SS PM" - "08:15:00 AM".
+	//   - "HH:MM" - "08:15".
+	//   - "HH:MM PM" - "08:15 AM".
+	TimePickerMin PropertyName = "time-picker-min"
+
+	// TimePickerMax is the constant for "time-picker-max" property tag.
+	//
+	// Used by TimePicker.
+	// The maximum value of the time.
+	//
+	// Supported types: time.Time, string.
+	//
+	// Internal type is time.Time, other types converted to it during assignment.
+	//
+	// Conversion rules:
+	// string - values of this type parsed and converted to time.Time. The following formats are supported:
+	//   - "HH:MM:SS" - "08:15:00".
+	//   - "HH:MM:SS PM" - "08:15:00 AM".
+	//   - "HH:MM" - "08:15".
+	//   - "HH:MM PM" - "08:15 AM".
+	TimePickerMax PropertyName = "time-picker-max"
+
+	// TimePickerStep is the constant for "time-picker-step" property tag.
+	//
+	// Used by TimePicker.
+	// Time step in seconds.
+	//
+	// Supported types: int, string.
+	//
+	// Values:
+	// positive value - Step value in seconds used to increment or decrement time.
+	TimePickerStep PropertyName = "time-picker-step"
+
+	// TimePickerValue is the constant for "time-picker-value" property tag.
+	//
+	// Used by TimePicker.
+	// Current value.
+	//
+	// Supported types: time.Time, string.
+	//
+	// Internal type is time.Time, other types converted to it during assignment.
+	//
+	// Conversion rules:
+	// string - values of this type parsed and converted to time.Time. The following formats are supported:
+	//   - "HH:MM:SS" - "08:15:00".
+	//   - "HH:MM:SS PM" - "08:15:00 AM".
+	//   - "HH:MM" - "08:15".
+	//   - "HH:MM PM" - "08:15 AM".
+	TimePickerValue PropertyName = "time-picker-value"
+
+	timeFormat = "15:04:05"
 )
 
-// TimePicker - TimePicker view
+// TimePicker represents a TimePicker view
 type TimePicker interface {
 	View
 }
 
 type timePickerData struct {
 	viewData
-	dataList
-	timeChangedListeners []func(TimePicker, time.Time, time.Time)
 }
 
 // NewTimePicker create new TimePicker object and return it
@@ -35,236 +112,154 @@ func NewTimePicker(session Session, params Params) TimePicker {
 }
 
 func newTimePicker(session Session) View {
-	return NewTimePicker(session, nil)
+	return new(timePickerData)
 }
 
 func (picker *timePickerData) init(session Session) {
 	picker.viewData.init(session)
 	picker.tag = "TimePicker"
 	picker.hasHtmlDisabled = true
-	picker.timeChangedListeners = []func(TimePicker, time.Time, time.Time){}
-	picker.dataListInit()
-}
-
-func (picker *timePickerData) String() string {
-	return getViewString(picker, nil)
+	picker.normalize = normalizeTimePickerTag
+	picker.set = picker.setFunc
+	picker.changed = picker.propertyChanged
 }
 
 func (picker *timePickerData) Focusable() bool {
 	return true
 }
 
-func (picker *timePickerData) normalizeTag(tag string) string {
-	tag = strings.ToLower(tag)
+func normalizeTimePickerTag(tag PropertyName) PropertyName {
+	tag = defaultNormalize(tag)
 	switch tag {
 	case Type, Min, Max, Step, Value:
 		return "time-picker-" + tag
 	}
 
-	return tag
+	return normalizeDataListTag(tag)
 }
 
-func (picker *timePickerData) Remove(tag string) {
-	picker.remove(picker.normalizeTag(tag))
-}
+func stringToTime(value string) (time.Time, bool) {
+	lowText := strings.ToUpper(value)
+	pm := strings.HasSuffix(lowText, "PM") || strings.HasSuffix(lowText, "AM")
 
-func (picker *timePickerData) remove(tag string) {
-	switch tag {
-	case TimeChangedEvent:
-		if len(picker.timeChangedListeners) > 0 {
-			picker.timeChangedListeners = []func(TimePicker, time.Time, time.Time){}
-			picker.propertyChangedEvent(tag)
-		}
-		return
-
-	case TimePickerMin:
-		delete(picker.properties, TimePickerMin)
-		if picker.created {
-			picker.session.removeProperty(picker.htmlID(), Min)
-		}
-
-	case TimePickerMax:
-		delete(picker.properties, TimePickerMax)
-		if picker.created {
-			picker.session.removeProperty(picker.htmlID(), Max)
-		}
-
-	case TimePickerStep:
-		delete(picker.properties, TimePickerStep)
-		if picker.created {
-			picker.session.removeProperty(picker.htmlID(), Step)
-		}
-
-	case TimePickerValue:
-		if _, ok := picker.properties[TimePickerValue]; ok {
-			oldTime := GetTimePickerValue(picker)
-			delete(picker.properties, TimePickerValue)
-			time := GetTimePickerValue(picker)
-			if picker.created {
-				picker.session.callFunc("setInputValue", picker.htmlID(), time.Format(timeFormat))
-			}
-			for _, listener := range picker.timeChangedListeners {
-				listener(picker, time, oldTime)
-			}
+	var format string
+	switch len(strings.Split(value, ":")) {
+	case 2:
+		if pm {
+			format = "3:04 PM"
 		} else {
-			return
-		}
-
-	case DataList:
-		if len(picker.dataList.dataList) > 0 {
-			picker.setDataList(picker, []string{}, true)
+			format = "15:04"
 		}
 
 	default:
-		picker.viewData.remove(tag)
-		return
-	}
-	picker.propertyChangedEvent(tag)
-}
-
-func (picker *timePickerData) Set(tag string, value any) bool {
-	return picker.set(picker.normalizeTag(tag), value)
-}
-
-func (picker *timePickerData) set(tag string, value any) bool {
-	if value == nil {
-		picker.remove(tag)
-		return true
+		if pm {
+			format = "03:04:05 PM"
+		} else {
+			format = "15:04:05"
+		}
 	}
 
-	setTimeValue := func(tag string) (time.Time, bool) {
+	result, err := time.Parse(format, value)
+	if err != nil {
+		ErrorLog(err.Error())
+		return time.Now(), false
+	}
+	return result, true
+}
+
+func (picker *timePickerData) setFunc(tag PropertyName, value any) []PropertyName {
+
+	setTimeValue := func(tag PropertyName) []PropertyName {
 		switch value := value.(type) {
 		case time.Time:
-			picker.properties[tag] = value
-			return value, true
+			picker.setRaw(tag, value)
+			return []PropertyName{tag}
 
 		case string:
-			if text, ok := picker.Session().resolveConstants(value); ok {
-				lowText := strings.ToLower(text)
-				pm := strings.HasSuffix(lowText, "pm") || strings.HasSuffix(lowText, "am")
+			if isConstantName(value) {
+				picker.setRaw(tag, value)
+				return []PropertyName{tag}
+			}
 
-				var format string
-				switch len(strings.Split(text, ":")) {
-				case 2:
-					if pm {
-						format = "3:04 PM"
-					} else {
-						format = "15:04"
-					}
-
-				default:
-					if pm {
-						format = "03:04:05 PM"
-					} else {
-						format = "15:04:05"
-					}
-				}
-
-				if time, err := time.Parse(format, text); err == nil {
-					picker.properties[tag] = value
-					return time, true
-				} else {
-					ErrorLog(err.Error())
-				}
-				return time.Now(), false
+			if time, ok := stringToTime(value); ok {
+				picker.setRaw(tag, time)
+				return []PropertyName{tag}
 			}
 		}
 
 		notCompatibleType(tag, value)
-		return time.Now(), false
+		return nil
 	}
 
 	switch tag {
 	case TimePickerMin:
-		old, oldOK := getTimeProperty(picker, TimePickerMin, Min)
-		if time, ok := setTimeValue(TimePickerMin); ok {
-			if !oldOK || time != old {
-				if picker.created {
-					picker.session.updateProperty(picker.htmlID(), Min, time.Format(timeFormat))
-				}
-				picker.propertyChangedEvent(tag)
-			}
-			return true
+		return setTimeValue(TimePickerMin)
+
+	case TimePickerMax:
+		return setTimeValue(TimePickerMax)
+
+	case TimePickerStep:
+		return setIntProperty(picker, TimePickerStep, value)
+
+	case TimePickerValue:
+		picker.setRaw("old-time", GetTimePickerValue(picker))
+		return setTimeValue(tag)
+
+	case TimeChangedEvent:
+		return setTwoArgEventListener[TimePicker, time.Time](picker, tag, value)
+
+	case DataList:
+		return setDataList(picker, value, timeFormat)
+	}
+
+	return picker.viewData.setFunc(tag, value)
+}
+
+func (picker *timePickerData) propertyChanged(tag PropertyName) {
+
+	session := picker.Session()
+
+	switch tag {
+
+	case TimePickerMin:
+		if time, ok := GetTimePickerMin(picker); ok {
+			session.updateProperty(picker.htmlID(), "min", time.Format(timeFormat))
+		} else {
+			session.removeProperty(picker.htmlID(), "min")
 		}
 
 	case TimePickerMax:
-		old, oldOK := getTimeProperty(picker, TimePickerMax, Max)
-		if time, ok := setTimeValue(TimePickerMax); ok {
-			if !oldOK || time != old {
-				if picker.created {
-					picker.session.updateProperty(picker.htmlID(), Max, time.Format(timeFormat))
-				}
-				picker.propertyChangedEvent(tag)
-			}
-			return true
+		if time, ok := GetTimePickerMax(picker); ok {
+			session.updateProperty(picker.htmlID(), "max", time.Format(timeFormat))
+		} else {
+			session.removeProperty(picker.htmlID(), "max")
 		}
 
 	case TimePickerStep:
-		oldStep := GetTimePickerStep(picker)
-		if picker.setIntProperty(TimePickerStep, value) {
-			if step := GetTimePickerStep(picker); oldStep != step {
-				if picker.created {
-					if step > 0 {
-						picker.session.updateProperty(picker.htmlID(), Step, strconv.Itoa(step))
-					} else {
-						picker.session.removeProperty(picker.htmlID(), Step)
-					}
-				}
-				picker.propertyChangedEvent(tag)
-			}
-			return true
+		if step := GetTimePickerStep(picker); step > 0 {
+			session.updateProperty(picker.htmlID(), "step", strconv.Itoa(step))
+		} else {
+			session.removeProperty(picker.htmlID(), "step")
 		}
 
 	case TimePickerValue:
-		oldTime := GetTimePickerValue(picker)
-		if time, ok := setTimeValue(TimePickerValue); ok {
-			if time != oldTime {
-				if picker.created {
-					picker.session.callFunc("setInputValue", picker.htmlID(), time.Format(timeFormat))
+		value := GetTimePickerValue(picker)
+		session.callFunc("setInputValue", picker.htmlID(), value.Format(timeFormat))
+
+		if listeners := GetTimeChangedListeners(picker); len(listeners) > 0 {
+			oldTime := time.Now()
+			if val := picker.getRaw("old-time"); val != nil {
+				if time, ok := val.(time.Time); ok {
+					oldTime = time
 				}
-				for _, listener := range picker.timeChangedListeners {
-					listener(picker, time, oldTime)
-				}
-				picker.propertyChangedEvent(tag)
 			}
-			return true
+			for _, listener := range listeners {
+				listener(picker, value, oldTime)
+			}
 		}
 
-	case TimeChangedEvent:
-		listeners, ok := valueToEventWithOldListeners[TimePicker, time.Time](value)
-		if !ok {
-			notCompatibleType(tag, value)
-			return false
-		} else if listeners == nil {
-			listeners = []func(TimePicker, time.Time, time.Time){}
-		}
-		picker.timeChangedListeners = listeners
-		picker.propertyChangedEvent(tag)
-		return true
-
-	case DataList:
-		return picker.setDataList(picker, value, picker.created)
-
 	default:
-		return picker.viewData.set(tag, value)
-	}
-	return false
-}
-
-func (picker *timePickerData) Get(tag string) any {
-	return picker.get(picker.normalizeTag(tag))
-}
-
-func (picker *timePickerData) get(tag string) any {
-	switch tag {
-	case TimeChangedEvent:
-		return picker.timeChangedListeners
-
-	case DataList:
-		return picker.dataList.dataList
-
-	default:
-		return picker.viewData.get(tag)
+		picker.viewData.propertyChanged(tag)
 	}
 }
 
@@ -273,7 +268,13 @@ func (picker *timePickerData) htmlTag() string {
 }
 
 func (picker *timePickerData) htmlSubviews(self View, buffer *strings.Builder) {
-	picker.dataListHtmlSubviews(self, buffer)
+	dataListHtmlSubviews(self, buffer, func(text string, session Session) string {
+		text, _ = session.resolveConstants(text)
+		if time, ok := stringToTime(text); ok {
+			return time.Format(timeFormat)
+		}
+		return text
+	})
 }
 
 func (picker *timePickerData) htmlProperties(self View, buffer *strings.Builder) {
@@ -308,20 +309,24 @@ func (picker *timePickerData) htmlProperties(self View, buffer *strings.Builder)
 		buffer.WriteString(` onclick="stopEventPropagation(this, event)"`)
 	}
 
-	picker.dataListHtmlProperties(picker, buffer)
+	dataListHtmlProperties(picker, buffer)
 }
 
-func (picker *timePickerData) handleCommand(self View, command string, data DataObject) bool {
+func (picker *timePickerData) handleCommand(self View, command PropertyName, data DataObject) bool {
 	switch command {
 	case "textChanged":
 		if text, ok := data.PropertyValue("text"); ok {
-			if value, err := time.Parse(timeFormat, text); err == nil {
+			if value, ok := stringToTime(text); ok {
 				oldValue := GetTimePickerValue(picker)
 				picker.properties[TimePickerValue] = value
 				if value != oldValue {
-					for _, listener := range picker.timeChangedListeners {
+					for _, listener := range GetTimeChangedListeners(picker) {
 						listener(picker, value, oldValue)
 					}
+					if listener, ok := picker.changeListener[TimePickerValue]; ok {
+						listener(picker, TimePickerValue)
+					}
+
 				}
 			}
 		}
@@ -331,7 +336,7 @@ func (picker *timePickerData) handleCommand(self View, command string, data Data
 	return picker.viewData.handleCommand(self, command, data)
 }
 
-func getTimeProperty(view View, mainTag, shortTag string) (time.Time, bool) {
+func getTimeProperty(view View, mainTag, shortTag PropertyName) (time.Time, bool) {
 	valueToTime := func(value any) (time.Time, bool) {
 		if value != nil {
 			switch value := value.(type) {
@@ -340,7 +345,7 @@ func getTimeProperty(view View, mainTag, shortTag string) (time.Time, bool) {
 
 			case string:
 				if text, ok := view.Session().resolveConstants(value); ok {
-					if result, err := time.Parse(timeFormat, text); err == nil {
+					if result, ok := stringToTime(text); ok {
 						return result, true
 					}
 				}
@@ -354,9 +359,11 @@ func getTimeProperty(view View, mainTag, shortTag string) (time.Time, bool) {
 			return result, true
 		}
 
-		if value := valueFromStyle(view, shortTag); value != nil {
-			if result, ok := valueToTime(value); ok {
-				return result, true
+		for _, tag := range []PropertyName{mainTag, shortTag} {
+			if value := valueFromStyle(view, tag); value != nil {
+				if result, ok := valueToTime(value); ok {
+					return result, true
+				}
 			}
 		}
 	}
@@ -368,10 +375,7 @@ func getTimeProperty(view View, mainTag, shortTag string) (time.Time, bool) {
 // "false" as the second value otherwise.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetTimePickerMin(view View, subviewID ...string) (time.Time, bool) {
-	if len(subviewID) > 0 && subviewID[0] != "" {
-		view = ViewByID(view, subviewID[0])
-	}
-	if view != nil {
+	if view = getSubview(view, subviewID); view != nil {
 		return getTimeProperty(view, TimePickerMin, Min)
 	}
 	return time.Now(), false
@@ -381,10 +385,7 @@ func GetTimePickerMin(view View, subviewID ...string) (time.Time, bool) {
 // "false" as the second value otherwise.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetTimePickerMax(view View, subviewID ...string) (time.Time, bool) {
-	if len(subviewID) > 0 && subviewID[0] != "" {
-		view = ViewByID(view, subviewID[0])
-	}
-	if view != nil {
+	if view = getSubview(view, subviewID); view != nil {
 		return getTimeProperty(view, TimePickerMax, Max)
 	}
 	return time.Now(), false
@@ -399,10 +400,7 @@ func GetTimePickerStep(view View, subviewID ...string) int {
 // GetTimePickerValue returns the time of TimePicker subview.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetTimePickerValue(view View, subviewID ...string) time.Time {
-	if len(subviewID) > 0 && subviewID[0] != "" {
-		view = ViewByID(view, subviewID[0])
-	}
-	if view == nil {
+	if view = getSubview(view, subviewID); view == nil {
 		return time.Now()
 	}
 	time, _ := getTimeProperty(view, TimePickerValue, Value)
@@ -413,5 +411,5 @@ func GetTimePickerValue(view View, subviewID ...string) time.Time {
 // If there are no listeners then the empty list is returned
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetTimeChangedListeners(view View, subviewID ...string) []func(TimePicker, time.Time, time.Time) {
-	return getEventWithOldListeners[TimePicker, time.Time](view, subviewID, TimeChangedEvent)
+	return getTwoArgEventListeners[TimePicker, time.Time](view, subviewID, TimeChangedEvent)
 }

touchEvents.go

@@ -2,34 +2,90 @@ package rui
 
 import (
 	"strconv"
-	"strings"
 )
 
+// Constants which represent [View] specific touch events properties
 const (
 	// TouchStart is the constant for "touch-start" property tag.
-	// The "touch-start" event is fired when one or more touch points are placed on the touch surface.
-	// The main listener format: func(View, TouchEvent).
-	// The additional listener formats: func(TouchEvent), func(View), and func().
-	TouchStart = "touch-start"
+	//
+	// Used by View.
+	// Is fired when one or more touch points are placed on the touch surface.
+	//
+	// General listener format:
+	//
+	//  func(view rui.View, event rui.TouchEvent)
+	//
+	// where:
+	//   - view - Interface of a view which generated this event,
+	//   - event - Touch event.
+	//
+	// Allowed listener formats:
+	//
+	//  func(event rui.TouchEvent)
+	//  func(view rui.View)
+	//  func()
+	TouchStart PropertyName = "touch-start"
 
 	// TouchEnd is the constant for "touch-end" property tag.
-	// The "touch-end" event fires when one or more touch points are removed from the touch surface.
-	// The main listener format: func(View, TouchEvent).
-	// The additional listener formats: func(TouchEvent), func(View), and func().
-	TouchEnd = "touch-end"
+	//
+	// Used by View.
+	// Fired when one or more touch points are removed from the touch surface.
+	//
+	// General listener format:
+	//
+	//  func(view rui.View, event rui.TouchEvent)
+	//
+	// where:
+	//   - view - Interface of a view which generated this event,
+	//   - event - Touch event.
+	//
+	// Allowed listener formats:
+	//
+	//  func(event rui.TouchEvent)
+	//  func(view rui.View)
+	//  func()
+	TouchEnd PropertyName = "touch-end"
 
 	// TouchMove is the constant for "touch-move" property tag.
-	// The "touch-move" event is fired when one or more touch points are moved along the touch surface.
-	// The main listener format: func(View, TouchEvent).
-	// The additional listener formats: func(TouchEvent), func(View), and func().
-	TouchMove = "touch-move"
+	//
+	// Used by View.
+	// Is fired when one or more touch points are moved along the touch surface.
+	//
+	// General listener format:
+	//
+	//  func(view rui.View, event rui.TouchEvent)
+	//
+	// where:
+	//   - view - Interface of a view which generated this event,
+	//   - event - Touch event.
+	//
+	// Allowed listener formats:
+	//
+	//  func(event rui.TouchEvent)
+	//  func(view rui.View)
+	//  func()
+	TouchMove PropertyName = "touch-move"
 
 	// TouchCancel is the constant for "touch-cancel" property tag.
-	// The "touch-cancel" event is fired when one or more touch points have been disrupted
-	// in an implementation-specific manner (for example, too many touch points are created).
-	// The main listener format: func(View, TouchEvent).
-	// The additional listener formats: func(TouchEvent), func(View), and func().
-	TouchCancel = "touch-cancel"
+	//
+	// Used by View.
+	// Is fired when one or more touch points have been disrupted in an implementation-specific manner (for example, too many
+	// touch points are created).
+	//
+	// General listener format:
+	//
+	//  func(view rui.View, event rui.TouchEvent)
+	//
+	// where:
+	//   - view - Interface of a view which generated this event,
+	//   - event - Touch event.
+	//
+	// Allowed listener formats:
+	//
+	//  func(event rui.TouchEvent)
+	//  func(view rui.View)
+	//  func()
+	TouchCancel PropertyName = "touch-cancel"
 )
 
 // Touch contains parameters of a single touch of a touch event
@@ -41,22 +97,26 @@ type Touch struct {
 
 	// X provides the horizontal coordinate within the view's viewport.
 	X float64
+
 	// Y provides the vertical coordinate within the view's viewport.
 	Y float64
 
 	// ClientX provides the horizontal coordinate within the application's viewport at which the event occurred.
 	ClientX float64
+
 	// ClientY provides the vertical coordinate within the application's viewport at which the event occurred.
 	ClientY float64
 
 	// ScreenX provides the horizontal coordinate (offset) of the touch pointer in global (screen) coordinates.
 	ScreenX float64
+
 	// ScreenY provides the vertical coordinate (offset) of the touch pointer in global (screen) coordinates.
 	ScreenY float64
 
 	// RadiusX is the X radius of the ellipse that most closely circumscribes the area of contact with the screen.
 	// The value is in pixels of the same scale as screenX.
 	RadiusX float64
+
 	// RadiusY is the Y radius of the ellipse that most closely circumscribes the area of contact with the screen.
 	// The value is in pixels of the same scale as screenX.
 	RadiusY float64
@@ -90,55 +150,6 @@ type TouchEvent struct {
 	MetaKey bool
 }
 
-var touchEvents = map[string]struct{ jsEvent, jsFunc string }{
-	TouchStart:  {jsEvent: "ontouchstart", jsFunc: "touchStartEvent"},
-	TouchEnd:    {jsEvent: "ontouchend", jsFunc: "touchEndEvent"},
-	TouchMove:   {jsEvent: "ontouchmove", jsFunc: "touchMoveEvent"},
-	TouchCancel: {jsEvent: "ontouchcancel", jsFunc: "touchCancelEvent"},
-}
-
-func (view *viewData) setTouchListener(tag string, value any) bool {
-	listeners, ok := valueToEventListeners[View, TouchEvent](value)
-	if !ok {
-		notCompatibleType(tag, value)
-		return false
-	}
-
-	if listeners == nil {
-		view.removeTouchListener(tag)
-	} else if js, ok := touchEvents[tag]; ok {
-		view.properties[tag] = listeners
-		if view.created {
-			view.session.updateProperty(view.htmlID(), js.jsEvent, js.jsFunc+"(this, event)")
-		}
-	} else {
-		return false
-	}
-	return true
-}
-
-func (view *viewData) removeTouchListener(tag string) {
-	delete(view.properties, tag)
-	if view.created {
-		if js, ok := touchEvents[tag]; ok {
-			view.session.removeProperty(view.htmlID(), js.jsEvent)
-		}
-	}
-}
-
-func touchEventsHtml(view View, buffer *strings.Builder) {
-	for tag, js := range touchEvents {
-		if value := view.getRaw(tag); value != nil {
-			if listeners, ok := value.([]func(View, TouchEvent)); ok && len(listeners) > 0 {
-				buffer.WriteString(js.jsEvent)
-				buffer.WriteString(`="`)
-				buffer.WriteString(js.jsFunc)
-				buffer.WriteString(`(this, event)" `)
-			}
-		}
-	}
-}
-
 func (event *TouchEvent) init(data DataObject) {
 
 	event.Touches = []Touch{}
@@ -172,8 +183,8 @@ func (event *TouchEvent) init(data DataObject) {
 	event.MetaKey = dataBoolProperty(data, "metaKey")
 }
 
-func handleTouchEvents(view View, tag string, data DataObject) {
-	listeners := getEventListeners[View, TouchEvent](view, nil, tag)
+func handleTouchEvents(view View, tag PropertyName, data DataObject) {
+	listeners := getOneArgEventListeners[View, TouchEvent](view, nil, tag)
 	if len(listeners) == 0 {
 		return
 	}
@@ -189,23 +200,23 @@ func handleTouchEvents(view View, tag string, data DataObject) {
 // GetTouchStartListeners returns the "touch-start" listener list. If there are no listeners then the empty list is returned.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetTouchStartListeners(view View, subviewID ...string) []func(View, TouchEvent) {
-	return getEventListeners[View, TouchEvent](view, subviewID, TouchStart)
+	return getOneArgEventListeners[View, TouchEvent](view, subviewID, TouchStart)
 }
 
 // GetTouchEndListeners returns the "touch-end" listener list. If there are no listeners then the empty list is returned.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetTouchEndListeners(view View, subviewID ...string) []func(View, TouchEvent) {
-	return getEventListeners[View, TouchEvent](view, subviewID, TouchEnd)
+	return getOneArgEventListeners[View, TouchEvent](view, subviewID, TouchEnd)
 }
 
 // GetTouchMoveListeners returns the "touch-move" listener list. If there are no listeners then the empty list is returned.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetTouchMoveListeners(view View, subviewID ...string) []func(View, TouchEvent) {
-	return getEventListeners[View, TouchEvent](view, subviewID, TouchMove)
+	return getOneArgEventListeners[View, TouchEvent](view, subviewID, TouchMove)
 }
 
 // GetTouchCancelListeners returns the "touch-cancel" listener list. If there are no listeners then the empty list is returned.
 // If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
 func GetTouchCancelListeners(view View, subviewID ...string) []func(View, TouchEvent) {
-	return getEventListeners[View, TouchEvent](view, subviewID, TouchCancel)
+	return getOneArgEventListeners[View, TouchEvent](view, subviewID, TouchCancel)
 }

transform.go

@@ -0,0 +1,739 @@
+package rui
+
+import (
+	"fmt"
+	"math"
+	"strings"
+)
+
+// Constants for [TransformProperty] specific properties
+const (
+	// Transform is the constant for "transform" property tag.
+	//
+	// Used by View.
+	// Specify translation, scale and rotation over x, y and z axes as well as a distortion of a view along x and y axes.
+	//
+	// Supported types: TransformProperty, string.
+	//
+	// See TransformProperty description for more details.
+	//
+	// Conversion rules:
+	//   - TransformProperty - stored as is, no conversion performed.
+	//   - string - string representation of TransformProperty interface. Example: "_{translate-x = 10px, scale-y = 1.1}".
+	Transform PropertyName = "transform"
+
+	// Perspective is the constant for "perspective" property tag.
+	//
+	// Used by View, TransformProperty.
+	// Distance between the z-plane and the user in order to give a 3D-positioned element some perspective. Each 3D element
+	// with z > 0 becomes larger, each 3D-element with z < 0 becomes smaller. The default value is 0 (no 3D effects).
+	//
+	// Supported types: SizeUnit, SizeFunc, string, float, int.
+	//
+	// Internal type is SizeUnit, other types converted to it during assignment.
+	// See SizeUnit description for more details.
+	Perspective PropertyName = "perspective"
+
+	// PerspectiveOriginX is the constant for "perspective-origin-x" property tag.
+	//
+	// Used by View.
+	// x-coordinate of the position at which the viewer is looking. It is used as the vanishing point by the "perspective"
+	// property. The default value is 50%.
+	//
+	// Supported types: SizeUnit, SizeFunc, string, float, int.
+	//
+	// Internal type is SizeUnit, other types converted to it during assignment.
+	// See SizeUnit description for more details.
+	PerspectiveOriginX PropertyName = "perspective-origin-x"
+
+	// PerspectiveOriginY is the constant for "perspective-origin-y" property tag.
+	//
+	// Used by View.
+	// y-coordinate of the position at which the viewer is looking. It is used as the vanishing point by the "perspective"
+	// property. The default value is 50%.
+	//
+	// Supported types: SizeUnit, SizeFunc, string, float, int.
+	//
+	// Internal type is SizeUnit, other types converted to it during assignment.
+	// See SizeUnit description for more details.
+	PerspectiveOriginY PropertyName = "perspective-origin-y"
+
+	// BackfaceVisible is the constant for "backface-visibility" property tag.
+	//
+	// Used by View.
+	// Controls whether the back face of a view is visible when turned towards the user. Default value is true.
+	//
+	// Supported types: bool, int, string.
+	//
+	// Values:
+	//   - true, 1, "true", "yes", "on", "1" - Back face is visible when turned towards the user.
+	//   - false, 0, "false", "no", "off", "0" - Back face is hidden, effectively making the view invisible when turned away from the user.
+	BackfaceVisible PropertyName = "backface-visibility"
+
+	// TransformOriginX is the constant for "transform-origin-x" property tag.
+	//
+	// Used by View.
+	// x-coordinate of the point around which a view transformation is applied. The default value is 50%.
+	//
+	// Supported types: SizeUnit, SizeFunc, string, float, int.
+	//
+	// Internal type is SizeUnit, other types converted to it during assignment.
+	// See SizeUnit description for more details.
+	TransformOriginX PropertyName = "transform-origin-x"
+
+	// TransformOriginY is the constant for "transform-origin-y" property tag.
+	//
+	// Used by View.
+	// y-coordinate of the point around which a view transformation is applied. The default value is 50%.
+	//
+	// Supported types: SizeUnit, SizeFunc, string, float, int.
+	//
+	// Internal type is SizeUnit, other types converted to it during assignment.
+	// See SizeUnit description for more details.
+	TransformOriginY PropertyName = "transform-origin-y"
+
+	// TransformOriginZ is the constant for "transform-origin-z" property tag.
+	//
+	// Used by View.
+	// z-coordinate of the point around which a view transformation is applied. The default value is 50%.
+	//
+	// Supported types: SizeUnit, SizeFunc, string, float, int.
+	//
+	// Internal type is SizeUnit, other types converted to it during assignment.
+	// See SizeUnit description for more details.
+	TransformOriginZ PropertyName = "transform-origin-z"
+
+	// TranslateX is the constant for "translate-x" property tag.
+	//
+	// Used by View, TransformProperty.
+	//
+	// x-axis translation value of a 2D/3D translation.
+	//
+	// Supported types: SizeUnit, SizeFunc, string, float, int.
+	//
+	// Internal type is SizeUnit, other types converted to it during assignment.
+	// See SizeUnit description for more details.
+	TranslateX PropertyName = "translate-x"
+
+	// TranslateY is the constant for "translate-y" property tag.
+	//
+	// Used by View, TransformProperty.
+	//
+	// x-axis translation value of a 2D/3D translation.
+	//
+	// Supported types: SizeUnit, SizeFunc, string, float, int.
+	//
+	// Internal type is SizeUnit, other types converted to it during assignment.
+	// See SizeUnit description for more details.
+	TranslateY PropertyName = "translate-y"
+
+	// TranslateZ is the constant for "translate-z" property tag.
+	//
+	// Used by View, TransformProperty.
+	//
+	// z-axis translation value of a 3D translation.
+	//
+	// Supported types: SizeUnit, SizeFunc, string, float, int.
+	//
+	// Internal type is SizeUnit, other types converted to it during assignment.
+	// See SizeUnit description for more details.
+	TranslateZ PropertyName = "translate-z"
+
+	// ScaleX is the constant for "scale-x" property tag.
+	//
+	// Used by View, TransformProperty.
+	//
+	// x-axis scaling value of a 2D/3D scale. The original scale is 1. Values between 0 and 1 are used to decrease original
+	// scale, more than 1 - to increase. The default value is 1.
+	//
+	// Supported types: float, int, string.
+	//
+	// Internal type is float, other types converted to it during assignment.
+	ScaleX PropertyName = "scale-x"
+
+	// ScaleY is the constant for "scale-y" property tag.
+	//
+	// Used by View, TransformProperty.
+	//
+	// y-axis scaling value of a 2D/3D scale. The original scale is 1. Values between 0 and 1 are used to decrease original
+	// scale, more than 1 - to increase. The default value is 1.
+	//
+	// Supported types: float, int, string.
+	//
+	// Internal type is float, other types converted to it during assignment.
+	ScaleY PropertyName = "scale-y"
+
+	// ScaleZ is the constant for "scale-z" property tag.
+	//
+	// Used by View, TransformProperty.
+	//
+	// z-axis scaling value of a 3D scale. The original scale is 1. Values between 0 and 1 are used to decrease original
+	// scale, more than 1 - to increase. The default value is 1.
+	//
+	// Supported types: float, int, string.
+	//
+	// Internal type is float, other types converted to it during assignment.
+	ScaleZ PropertyName = "scale-z"
+
+	// Rotate is the constant for "rotate" property tag.
+	//
+	// Used by View, TransformProperty.
+	//
+	// Angle of the view rotation. A positive angle denotes a clockwise rotation, a negative angle a counter-clockwise.
+	//
+	// Supported types: AngleUnit, string, float, int.
+	//
+	// Internal type is AngleUnit, other types will be converted to it during assignment.
+	// See AngleUnit description for more details.
+	//
+	// Conversion rules:
+	//   - AngleUnit - stored as is, no conversion performed.
+	//   - string - must contain string representation of AngleUnit. If numeric value will be provided without any suffix then AngleUnit with value and Radian value type will be created.
+	//   - float - a new AngleUnit value will be created with Radian as a type.
+	//   - int - a new AngleUnit value will be created with Radian as a type.
+	Rotate PropertyName = "rotate"
+
+	// RotateX is the constant for "rotate-x" property tag.
+	//
+	// Used by View, TransformProperty.
+	//
+	// x-coordinate of the vector denoting the axis of rotation in range 0 to 1.
+	//
+	// Supported types: float, int, string.
+	//
+	// Internal type is float, other types converted to it during assignment.
+	RotateX PropertyName = "rotate-x"
+
+	// RotateY is the constant for "rotate-y" property tag.
+	//
+	// Used by View, TransformProperty.
+	//
+	// y-coordinate of the vector denoting the axis of rotation in range 0 to 1.
+	//
+	// Supported types: float, int, string.
+	//
+	// Internal type is float, other types converted to it during assignment.
+	RotateY PropertyName = "rotate-y"
+
+	// RotateZ is the constant for "rotate-z" property tag.
+	//
+	// Used by View, TransformProperty.
+	//
+	// z-coordinate of the vector denoting the axis of rotation in range 0 to 1.
+	//
+	// Supported types: float, int, string.
+	//
+	// Internal type is float, other types converted to it during assignment.
+	RotateZ PropertyName = "rotate-z"
+
+	// SkewX is the constant for "skew-x" property tag.
+	//
+	// Used by View, TransformProperty.
+	//
+	// Angle to use to distort the element along the abscissa. The default value is 0.
+	//
+	// Supported types: AngleUnit, string, float, int.
+	//
+	// Internal type is AngleUnit, other types will be converted to it during assignment.
+	// See AngleUnit description for more details.
+	//
+	// Conversion rules:
+	//   - AngleUnit - stored as is, no conversion performed.
+	//   - string - must contain string representation of AngleUnit. If numeric value will be provided without any suffix then AngleUnit with value and Radian value type will be created.
+	//   - float - a new AngleUnit value will be created with Radian as a type.
+	//   - int - a new AngleUnit value will be created with Radian as a type.
+	SkewX PropertyName = "skew-x"
+
+	// SkewY is the constant for "skew-y" property tag.
+	//
+	// Used by View, TransformProperty.
+	//
+	// Angle to use to distort the element along the ordinate. The default value is 0.
+	//
+	// Supported types: AngleUnit, string, float, int.
+	//
+	// Internal type is AngleUnit, other types will be converted to it during assignment.
+	// See AngleUnit description for more details.
+	//
+	// Conversion rules:
+	//   - AngleUnit - stored as is, no conversion performed.
+	//   - string - must contain string representation of AngleUnit. If numeric value will be provided without any suffix then AngleUnit with value and Radian value type will be created.
+	//   - float - a new AngleUnit value will be created with Radian as a type.
+	//   - int - a new AngleUnit value will be created with Radian as a type.
+	SkewY PropertyName = "skew-y"
+)
+
+// TransformProperty interface specifies view transformation parameters: the x-, y-, and z-axis translation values,
+// the x-, y-, and z-axis scaling values, the angle to use to distort the element along the abscissa and ordinate,
+// the angle of the view rotation.
+//
+// Valid property tags: Perspective ("perspective"),  TranslateX ("translate-x"), TranslateY ("translate-y"), TranslateZ ("translate-z"),
+// ScaleX ("scale-x"), ScaleY ("scale-y"), ScaleZ ("scale-z"), Rotate ("rotate"), RotateX ("rotate-x"),
+// RotateY ("rotate-y"), RotateZ ("rotate-z"), SkewX ("skew-x"), and SkewY ("skew-y")
+type TransformProperty interface {
+	Properties
+	fmt.Stringer
+	stringWriter
+	transformCSS(session Session) string
+	getSkew(session Session) (AngleUnit, AngleUnit, bool)
+	getTranslate(session Session) (SizeUnit, SizeUnit, SizeUnit)
+}
+
+type transformPropertyData struct {
+	dataProperty
+}
+
+// NewTransform creates a new transform property data and return its interface
+//
+// The following properties can be used:
+//
+// Perspective ("perspective"),  TranslateX ("translate-x"), TranslateY ("translate-y"), TranslateZ ("translate-z"),
+// ScaleX ("scale-x"), ScaleY ("scale-y"), ScaleZ ("scale-z"), Rotate ("rotate"), RotateX ("rotate-x"),
+// RotateY ("rotate-y"), RotateZ ("rotate-z"), SkewX ("skew-x"), and SkewY ("skew-y")
+func NewTransformProperty(params Params) TransformProperty {
+	transform := new(transformPropertyData)
+	transform.init()
+
+	for tag, value := range params {
+		transform.Set(tag, value)
+	}
+	return transform
+}
+
+func (transform *transformPropertyData) init() {
+	transform.dataProperty.init()
+	transform.normalize = normalizeTransformTag
+	transform.set = transformSet
+	transform.supportedProperties = []PropertyName{
+		RotateX, RotateY, RotateZ, Rotate, SkewX, SkewY, ScaleX, ScaleY, ScaleZ,
+		Perspective, TranslateX, TranslateY, TranslateZ,
+	}
+}
+
+func normalizeTransformTag(tag PropertyName) PropertyName {
+	tag = defaultNormalize(tag)
+
+	name := string(tag)
+	if strings.HasPrefix(name, "push-") {
+		tag = PropertyName(name[5:])
+	}
+
+	return tag
+}
+
+func (transform *transformPropertyData) String() string {
+	buffer := allocStringBuilder()
+	defer freeStringBuilder(buffer)
+	transform.writeString(buffer, "")
+	return buffer.String()
+}
+
+func (transform *transformPropertyData) writeString(buffer *strings.Builder, indent string) {
+	buffer.WriteString("_{ ")
+	comma := false
+	for _, tag := range transform.supportedProperties {
+		if value, ok := transform.properties[tag]; ok {
+			if comma {
+				buffer.WriteString(", ")
+			}
+			buffer.WriteString(string(tag))
+			buffer.WriteString(" = ")
+			writePropertyValue(buffer, tag, value, indent)
+			comma = true
+		}
+	}
+	buffer.WriteString(" }")
+}
+
+func transformSet(properties Properties, tag PropertyName, value any) []PropertyName {
+	switch tag {
+
+	case RotateX, RotateY, RotateZ:
+		return setFloatProperty(properties, tag, value, 0, 1)
+
+	case Rotate, SkewX, SkewY:
+		return setAngleProperty(properties, tag, value)
+
+	case ScaleX, ScaleY, ScaleZ:
+		return setFloatProperty(properties, tag, value, -math.MaxFloat64, math.MaxFloat64)
+
+	case Perspective, TranslateX, TranslateY, TranslateZ:
+		return setSizeProperty(properties, tag, value)
+	}
+
+	return nil
+}
+
+func valueToTransformProperty(value any) TransformProperty {
+
+	parseObject := func(obj DataObject) TransformProperty {
+		transform := NewTransformProperty(nil)
+		ok := true
+		for i := 0; i < obj.PropertyCount(); i++ {
+			if prop := obj.Property(i); prop.Type() == TextNode {
+				if !transform.Set(PropertyName(prop.Tag()), prop.Text()) {
+					ok = false
+				}
+			} else {
+				ok = false
+			}
+		}
+
+		if !ok && transform.empty() {
+			return nil
+		}
+		return transform
+	}
+
+	switch value := value.(type) {
+	case TransformProperty:
+		return value
+
+	case DataObject:
+		return parseObject(value)
+
+	case DataNode:
+		if obj := value.Object(); obj != nil {
+			return parseObject(obj)
+		}
+
+	case string:
+		if obj := ParseDataText(value); obj != nil {
+			return parseObject(obj)
+		}
+	}
+
+	return nil
+}
+
+func setTransformProperty(properties Properties, tag PropertyName, value any) bool {
+	if transform := valueToTransformProperty(value); transform != nil {
+		properties.setRaw(tag, transform)
+		return true
+	}
+
+	notCompatibleType(tag, value)
+	return false
+}
+
+func getTransformProperty(properties Properties, tag PropertyName) TransformProperty {
+	if val := properties.getRaw(tag); val != nil {
+		if transform, ok := val.(TransformProperty); ok {
+			return transform
+		}
+	}
+	return nil
+}
+
+func setTransformPropertyElement(properties Properties, tag, transformTag PropertyName, value any) []PropertyName {
+	srcTag := tag
+	tag = normalizeTransformTag(tag)
+	switch tag {
+	case Perspective, RotateX, RotateY, RotateZ, Rotate, SkewX, SkewY, ScaleX, ScaleY, ScaleZ, TranslateX, TranslateY, TranslateZ:
+		var result []PropertyName = nil
+		if transform := getTransformProperty(properties, transformTag); transform != nil {
+			if result = transformSet(transform, tag, value); result != nil {
+				result = []PropertyName{srcTag, transformTag}
+			}
+		} else {
+			transform := NewTransformProperty(nil)
+			if result = transformSet(transform, tag, value); result != nil {
+				properties.setRaw(transformTag, transform)
+				result = []PropertyName{srcTag, transformTag}
+			}
+		}
+		return result
+	}
+
+	ErrorLogF(`"TransformProperty" interface does not support the "%s" property`, tag)
+	return nil
+}
+
+func getPerspectiveOrigin(style Properties, session Session) (SizeUnit, SizeUnit) {
+	x, _ := sizeProperty(style, PerspectiveOriginX, session)
+	y, _ := sizeProperty(style, PerspectiveOriginY, session)
+	return x, y
+}
+
+func getTransformOrigin(style Properties, session Session) (SizeUnit, SizeUnit, SizeUnit) {
+	x, _ := sizeProperty(style, TransformOriginX, session)
+	y, _ := sizeProperty(style, TransformOriginY, session)
+	z, _ := sizeProperty(style, TransformOriginZ, session)
+	return x, y, z
+}
+
+func (transform *transformPropertyData) getSkew(session Session) (AngleUnit, AngleUnit, bool) {
+	skewX, okX := angleProperty(transform, SkewX, session)
+	skewY, okY := angleProperty(transform, SkewY, session)
+	return skewX, skewY, okX || okY
+}
+
+func (transform *transformPropertyData) getTranslate(session Session) (SizeUnit, SizeUnit, SizeUnit) {
+	x, _ := sizeProperty(transform, TranslateX, session)
+	y, _ := sizeProperty(transform, TranslateY, session)
+	z, _ := sizeProperty(transform, TranslateZ, session)
+	return x, y, z
+}
+
+func (transform *transformPropertyData) transformCSS(session Session) string {
+
+	buffer := allocStringBuilder()
+	defer freeStringBuilder(buffer)
+
+	if perspective, ok := sizeProperty(transform, Perspective, session); ok && perspective.Type != Auto && perspective.Value != 0 {
+		buffer.WriteString(`perspective(`)
+		buffer.WriteString(perspective.cssString("0", session))
+		buffer.WriteString(") ")
+	}
+
+	skewX, skewY, skewOK := transform.getSkew(session)
+	if skewOK {
+		buffer.WriteString(`skew(`)
+		buffer.WriteString(skewX.cssString())
+		buffer.WriteRune(',')
+		buffer.WriteString(skewY.cssString())
+		buffer.WriteString(") ")
+	}
+
+	x, y, z := transform.getTranslate(session)
+	if z.Type != Auto && z.Value != 0 {
+
+		buffer.WriteString(`translate3d(`)
+		buffer.WriteString(x.cssString("0px", session))
+		buffer.WriteRune(',')
+		buffer.WriteString(y.cssString("0px", session))
+		buffer.WriteRune(',')
+		buffer.WriteString(z.cssString("0px", session))
+		buffer.WriteString(") ")
+
+	} else if (x.Type != Auto && x.Value != 0) || (y.Type != Auto && y.Value != 0) {
+
+		buffer.WriteString(`translate(`)
+		buffer.WriteString(x.cssString("0px", session))
+		buffer.WriteRune(',')
+		buffer.WriteString(y.cssString("0px", session))
+		buffer.WriteString(") ")
+	}
+
+	scaleX, okScaleX := floatTextProperty(transform, ScaleX, session, 1)
+	scaleY, okScaleY := floatTextProperty(transform, ScaleY, session, 1)
+	scaleZ, okScaleZ := floatTextProperty(transform, ScaleZ, session, 1)
+	if okScaleZ {
+
+		buffer.WriteString(`scale3d(`)
+		buffer.WriteString(scaleX)
+		buffer.WriteRune(',')
+		buffer.WriteString(scaleY)
+		buffer.WriteRune(',')
+		buffer.WriteString(scaleZ)
+		buffer.WriteString(") ")
+
+	} else if okScaleX || okScaleY {
+
+		buffer.WriteString(`scale(`)
+		buffer.WriteString(scaleX)
+		buffer.WriteRune(',')
+		buffer.WriteString(scaleY)
+		buffer.WriteString(") ")
+	}
+
+	if angle, ok := angleProperty(transform, Rotate, session); ok {
+		rotateX, xOK := floatTextProperty(transform, RotateX, session, 1)
+		rotateY, yOK := floatTextProperty(transform, RotateY, session, 1)
+		rotateZ, zOK := floatTextProperty(transform, RotateZ, session, 1)
+
+		if xOK || yOK || zOK {
+
+			buffer.WriteString(`rotate3d(`)
+			buffer.WriteString(rotateX)
+			buffer.WriteRune(',')
+			buffer.WriteString(rotateY)
+			buffer.WriteRune(',')
+			buffer.WriteString(rotateZ)
+			buffer.WriteRune(',')
+			buffer.WriteString(angle.cssString())
+			buffer.WriteString(") ")
+
+		} else {
+
+			buffer.WriteString(`rotate(`)
+			buffer.WriteString(angle.cssString())
+			buffer.WriteString(") ")
+		}
+	}
+
+	length := buffer.Len()
+	if length == 0 {
+		return ""
+	}
+	result := buffer.String()
+	return result[:length-1]
+}
+
+func (style *viewStyle) writeViewTransformCSS(builder cssBuilder, session Session) {
+	x, y := getPerspectiveOrigin(style, session)
+	z := AutoSize()
+	if css := transformOriginCSS(x, y, z, session); css != "" {
+		builder.add(`perspective-origin`, css)
+	}
+
+	if backfaceVisible, ok := boolProperty(style, BackfaceVisible, session); ok {
+		if backfaceVisible {
+			builder.add(`backface-visibility`, `visible`)
+		} else {
+			builder.add(`backface-visibility`, `hidden`)
+		}
+	}
+
+	x, y, z = getTransformOrigin(style, session)
+	if css := transformOriginCSS(x, y, z, session); css != "" {
+		builder.add(`transform-origin`, css)
+	}
+
+	if transform := getTransformProperty(style, Transform); transform != nil {
+		builder.add(`transform`, transform.transformCSS(session))
+	}
+}
+
+func transformOriginCSS(x, y, z SizeUnit, session Session) string {
+	if z.Type == Auto && x.Type == Auto && y.Type == Auto {
+		return ""
+	}
+
+	buffer := allocStringBuilder()
+	defer freeStringBuilder(buffer)
+
+	if x.Type == SizeInPercent {
+		switch x.Value {
+		case 0:
+			buffer.WriteString("left")
+		case 50:
+			buffer.WriteString("center")
+		case 100:
+			buffer.WriteString("right")
+
+		default:
+			buffer.WriteString(x.cssString("center", session))
+		}
+	} else {
+		buffer.WriteString(x.cssString("center", session))
+	}
+
+	buffer.WriteRune(' ')
+
+	if y.Type == SizeInPercent {
+		switch y.Value {
+		case 0:
+			buffer.WriteString("top")
+		case 50:
+			buffer.WriteString("center")
+		case 100:
+			buffer.WriteString("bottom")
+
+		default:
+			buffer.WriteString(y.cssString("center", session))
+		}
+	} else {
+		buffer.WriteString(y.cssString("center", session))
+	}
+
+	if z.Type != Auto && z.Value != 0 {
+		buffer.WriteRune(' ')
+		buffer.WriteString(z.cssString("0", session))
+	}
+
+	return buffer.String()
+}
+
+// GetTransform returns a view transform:  translation, scale and rotation over x, y and z axes as well as a distortion of a view along x and y axes.
+// The default value is nil (no transform)
+// If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
+func GetTransform(view View, subviewID ...string) TransformProperty {
+	return transformStyledProperty(view, subviewID, Transform)
+}
+
+// GetPerspective returns a distance between the z = 0 plane and the user in order to give a 3D-positioned
+// element some perspective. Each 3D element with z > 0 becomes larger; each 3D-element with z < 0 becomes smaller.
+// The default value is 0 (no 3D effects).
+// If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
+func GetPerspective(view View, subviewID ...string) SizeUnit {
+	return sizeStyledProperty(view, subviewID, Perspective, false)
+}
+
+// GetPerspectiveOrigin returns a x- and y-coordinate of the position at which the viewer is looking.
+// It is used as the vanishing point by the Perspective property. The default value is (50%, 50%).
+// If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
+func GetPerspectiveOrigin(view View, subviewID ...string) (SizeUnit, SizeUnit) {
+	view = getSubview(view, subviewID)
+	if view == nil {
+		return AutoSize(), AutoSize()
+	}
+	return getPerspectiveOrigin(view, view.Session())
+}
+
+// GetBackfaceVisible returns a bool property that sets whether the back face of an element is
+// visible when turned towards the user. Values:
+// true - the back face is visible when turned towards the user (default value).
+// false - the back face is hidden, effectively making the element invisible when turned away from the user.
+// If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
+func GetBackfaceVisible(view View, subviewID ...string) bool {
+	return boolStyledProperty(view, subviewID, BackfaceVisible, false)
+}
+
+// GetTransformOrigin returns a x-, y-, and z-coordinate of the point around which a view transformation is applied.
+// The default value is (50%, 50%, 50%).
+// If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
+func GetTransformOrigin(view View, subviewID ...string) (SizeUnit, SizeUnit, SizeUnit) {
+	view = getSubview(view, subviewID)
+	if view == nil {
+		return AutoSize(), AutoSize(), AutoSize()
+	}
+	return getTransformOrigin(view, view.Session())
+}
+
+// GetTranslate returns a x-, y-, and z-axis translation value of a 2D/3D translation
+// If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
+func GetTranslate(view View, subviewID ...string) (SizeUnit, SizeUnit, SizeUnit) {
+	if transform := GetTransform(view, subviewID...); transform != nil {
+		return transform.getTranslate(view.Session())
+	}
+	return AutoSize(), AutoSize(), AutoSize()
+}
+
+// GetSkew returns a angles to use to distort the element along the abscissa (x-axis)
+// and the ordinate (y-axis). The default value is 0.
+// If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
+func GetSkew(view View, subviewID ...string) (AngleUnit, AngleUnit) {
+	if transform := GetTransform(view, subviewID...); transform != nil {
+		x, y, _ := transform.getSkew(view.Session())
+		return x, y
+	}
+	return AngleUnit{Value: 0, Type: Radian}, AngleUnit{Value: 0, Type: Radian}
+}
+
+// GetScale returns a x-, y-, and z-axis scaling value of a 2D/3D scale. The default value is 1.
+// If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
+func GetScale(view View, subviewID ...string) (float64, float64, float64) {
+	if transform := GetTransform(view, subviewID...); transform != nil {
+		session := view.Session()
+		x, _ := floatProperty(transform, ScaleX, session, 1)
+		y, _ := floatProperty(transform, ScaleY, session, 1)
+		z, _ := floatProperty(transform, ScaleZ, session, 1)
+		return x, y, z
+	}
+	return 1, 1, 1
+}
+
+// GetRotate returns a x-, y, z-coordinate of the vector denoting the axis of rotation, and the angle of the view rotation
+// If the second argument (subviewID) is not specified or it is "" then a value from the first argument (view) is returned.
+func GetRotate(view View, subviewID ...string) (float64, float64, float64, AngleUnit) {
+	if transform := GetTransform(view, subviewID...); transform != nil {
+		session := view.Session()
+		angle, _ := angleProperty(transform, Rotate, view.Session())
+		rotateX, _ := floatProperty(transform, RotateX, session, 1)
+		rotateY, _ := floatProperty(transform, RotateY, session, 1)
+		rotateZ, _ := floatProperty(transform, RotateZ, session, 1)
+		return rotateX, rotateY, rotateZ, angle
+	}
+	return 0, 0, 0, AngleUnit{Value: 0, Type: Radian}
+}

utils.go

@@ -6,38 +6,37 @@ import (
 	"path/filepath"
 	"strconv"
 	"strings"
+	"sync"
 )
 
-var stringBuilders []*strings.Builder = make([]*strings.Builder, 4096)
-var stringBuilderCount = 0
+const stringBuilderCap = 4096
+
+var stringBuilderPool = sync.Pool{
+	New: func() any {
+		result := new(strings.Builder)
+		result.Grow(stringBuilderCap)
+		return result
+	},
+}
 
 func allocStringBuilder() *strings.Builder {
-	for stringBuilderCount > 0 {
-		stringBuilderCount--
-		result := stringBuilders[stringBuilderCount]
-		if result != nil {
-			stringBuilders[stringBuilderCount] = nil
-			result.Reset()
-			return result
-		}
+	if builder := stringBuilderPool.Get(); builder != nil {
+		return builder.(*strings.Builder)
 	}
 
 	result := new(strings.Builder)
-	result.Grow(4096)
+	result.Grow(stringBuilderCap)
 	return result
 }
 
 func freeStringBuilder(builder *strings.Builder) {
-	if builder != nil {
-		if stringBuilderCount == len(stringBuilders) {
-			stringBuilders = append(stringBuilders, builder)
-		} else {
-			stringBuilders[stringBuilderCount] = builder
-		}
-		stringBuilderCount++
+	if builder != nil && builder.Cap() == stringBuilderCap {
+		builder.Reset()
+		stringBuilderPool.Put(builder)
 	}
 }
 
+// GetLocalIP return IP address of the machine interface
 func GetLocalIP() string {
 	addrs, err := net.InterfaceAddrs()
 	if err != nil {

videoPlayer.go

@@ -4,22 +4,40 @@ import (
 	"strings"
 )
 
+// Constants for [VideoPlayer] specific properties and events
 const (
-	// VideoWidth is the constant for the "video-width" property tag of VideoPlayer.
-	// The "video-width" float property defines the width of the video's display area in pixels.
-	VideoWidth = "video-width"
+	// VideoWidth is the constant for "video-width" property tag.
+	//
+	// Used by VideoPlayer.
+	// Defines the width of the video's display area in pixels.
+	//
+	// Supported types: float, int, string.
+	//
+	// Values:
+	// Internal type is float, other types converted to it during assignment.
+	VideoWidth PropertyName = "video-width"
 
-	// VideoHeight is the constant for the "video-height" property tag of VideoPlayer.
-	// The "video-height" float property defines the height of the video's display area in pixels.
-	VideoHeight = "video-height"
+	// VideoHeight is the constant for "video-height" property tag.
+	//
+	// Used by VideoPlayer.
+	// Defines the height of the video's display area in pixels.
+	//
+	// Supported types: float, int, string.
+	//
+	// Internal type is float, other types converted to it during assignment.
+	VideoHeight PropertyName = "video-height"
 
-	// Poster is the constant for the "poster" property tag of VideoPlayer.
-	// The "poster" property defines an URL for an image to be shown while the video is downloading.
-	// If this attribute isn't specified, nothing is displayed until the first frame is available,
-	// then the first frame is shown as the poster frame.
-	Poster = "poster"
+	// Poster is the constant for "poster" property tag.
+	//
+	// Used by VideoPlayer.
+	// Defines an URL for an image to be shown while the video is downloading. If this attribute isn't specified, nothing is
+	// displayed until the first frame is available, then the first frame is shown as the poster frame.
+	//
+	// Supported types: string.
+	Poster PropertyName = "poster"
 )
 
+// VideoPlayer is a type of a [View] which can play video files
 type VideoPlayer interface {
 	MediaPlayer
 }
@@ -32,92 +50,56 @@ type videoPlayerData struct {
 func NewVideoPlayer(session Session, params Params) VideoPlayer {
 	view := new(videoPlayerData)
 	view.init(session)
-	view.tag = "VideoPlayer"
 	setInitParams(view, params)
 	return view
 }
 
 func newVideoPlayer(session Session) View {
-	return NewVideoPlayer(session, nil)
+	return new(videoPlayerData) // NewVideoPlayer(session, nil)
 }
 
 func (player *videoPlayerData) init(session Session) {
 	player.mediaPlayerData.init(session)
 	player.tag = "VideoPlayer"
-}
-
-func (player *videoPlayerData) String() string {
-	return getViewString(player, nil)
+	player.changed = player.propertyChanged
 }
 
 func (player *videoPlayerData) htmlTag() string {
 	return "video"
 }
 
-func (player *videoPlayerData) Remove(tag string) {
-	player.remove(strings.ToLower(tag))
-}
+func (player *videoPlayerData) propertyChanged(tag PropertyName) {
+
+	session := player.Session()
+	updateSize := func(cssTag string) {
+		if size, ok := floatTextProperty(player, tag, session, 0); ok {
+			if size != "0" {
+				session.updateProperty(player.htmlID(), cssTag, size)
+			} else {
+				session.removeProperty(player.htmlID(), cssTag)
+			}
+		}
+	}
 
-func (player *videoPlayerData) remove(tag string) {
 	switch tag {
-
 	case VideoWidth:
-		delete(player.properties, tag)
-		player.session.removeProperty(player.htmlID(), "width")
+		updateSize("width")
 
 	case VideoHeight:
-		delete(player.properties, tag)
-		player.session.removeProperty(player.htmlID(), "height")
+		updateSize("height")
 
 	case Poster:
-		delete(player.properties, tag)
-		player.session.removeProperty(player.htmlID(), Poster)
+		if url, ok := stringProperty(player, Poster, session); ok {
+			session.updateProperty(player.htmlID(), string(Poster), url)
+		} else {
+			session.removeProperty(player.htmlID(), string(Poster))
+		}
 
 	default:
-		player.mediaPlayerData.remove(tag)
+		player.mediaPlayerData.propertyChanged(tag)
 	}
 }
 
-func (player *videoPlayerData) Set(tag string, value any) bool {
-	return player.set(strings.ToLower(tag), value)
-}
-
-func (player *videoPlayerData) set(tag string, value any) bool {
-	if value == nil {
-		player.remove(tag)
-		return true
-	}
-
-	if player.mediaPlayerData.set(tag, value) {
-		session := player.Session()
-		updateSize := func(cssTag string) {
-			if size, ok := floatTextProperty(player, tag, session, 0); ok {
-				if size != "0" {
-					session.updateProperty(player.htmlID(), cssTag, size)
-				} else {
-					session.removeProperty(player.htmlID(), cssTag)
-				}
-			}
-		}
-
-		switch tag {
-		case VideoWidth:
-			updateSize("width")
-
-		case VideoHeight:
-			updateSize("height")
-
-		case Poster:
-			if url, ok := stringProperty(player, Poster, session); ok {
-				session.updateProperty(player.htmlID(), Poster, url)
-			}
-		}
-		return true
-	}
-
-	return false
-}
-
 func (player *videoPlayerData) htmlProperties(self View, buffer *strings.Builder) {
 	player.mediaPlayerData.htmlProperties(self, buffer)
 

viewByID.go

@@ -2,34 +2,45 @@ package rui
 
 import "strings"
 
-// ViewByID return a View with id equal to the argument of the function or nil if there is no such View
-func ViewByID(rootView View, id string) View {
+// ViewByID returns the child View path to which is specified using the arguments id, ids. Example
+//
+//	view := ViewByID(rootView, "id1", "id2", "id3")
+//	view := ViewByID(rootView, "id1/id2/id3")
+//
+// These two function calls are equivalent.
+// If a View with this path is not found, the function will return nil
+func ViewByID(rootView View, id string, ids ...string) View {
 	if rootView == nil {
 		ErrorLog(`ViewByID(nil, "` + id + `"): rootView is nil`)
 		return nil
 	}
-	if rootView.ID() == id {
-		return rootView
+
+	path := []string{id}
+	if len(ids) > 0 {
+		path = append(path, ids...)
 	}
 
-	if container, ok := rootView.(ParentView); ok {
-		if view := viewByID(container, id); view != nil {
-			return view
-		}
-	}
-
-	if index := strings.IndexRune(id, '/'); index > 0 {
-		if view2 := ViewByID(rootView, id[:index]); view2 != nil {
-			if view := ViewByID(view2, id[index+1:]); view != nil {
-				return view
+	result := rootView
+	for _, id := range path {
+		if result.ID() != id {
+			if container, ok := result.(ParentView); ok {
+				if view := viewByID(container, id); view != nil {
+					result = view
+				} else if index := strings.IndexRune(id, '/'); index > 0 {
+					if view := ViewByID(result, id[:index], id[index+1:]); view != nil {
+						result = view
+					} else {
+						ErrorLog(`ViewByID(_, "` + id + `"): View not found`)
+						return nil
+					}
+				} else {
+					ErrorLog(`ViewByID(_, "` + id + `"): View not found`)
+					return nil
+				}
 			}
-			return nil
 		}
-		return nil
 	}
-
-	ErrorLog(`ViewByID(_, "` + id + `"): View not found`)
-	return nil
+	return result
 }
 
 func viewByID(rootView ParentView, id string) View {
@@ -49,10 +60,15 @@ func viewByID(rootView ParentView, id string) View {
 	return nil
 }
 
-// ViewsContainerByID return a ViewsContainer with id equal to the argument of the function or
-// nil if there is no such View or View is not ViewsContainer
-func ViewsContainerByID(rootView View, id string) ViewsContainer {
-	if view := ViewByID(rootView, id); view != nil {
+// ViewsContainerByID return the ViewsContainer path to which is specified using the arguments id, ids. Example
+//
+//	view := ViewsContainerByID(rootView, "id1", "id2", "id3")
+//	view := ViewsContainerByID(rootView, "id1/id2/id3")
+//
+// These two function calls are equivalent.
+// If a View with this path is not found or View is not ViewsContainer, the function will return nil
+func ViewsContainerByID(rootView View, id string, ids ...string) ViewsContainer {
+	if view := ViewByID(rootView, id, ids...); view != nil {
 		if list, ok := view.(ViewsContainer); ok {
 			return list
 		}
@@ -61,10 +77,15 @@ func ViewsContainerByID(rootView View, id string) ViewsContainer {
 	return nil
 }
 
-// ListLayoutByID return a ListLayout with id equal to the argument of the function or
-// nil if there is no such View or View is not ListLayout
-func ListLayoutByID(rootView View, id string) ListLayout {
-	if view := ViewByID(rootView, id); view != nil {
+// ListLayoutByID return the ListLayout  path to which is specified using the arguments id, ids. Example
+//
+//	view := ListLayoutByID(rootView, "id1", "id2", "id3")
+//	view := ListLayoutByID(rootView, "id1/id2/id3")
+//
+// These two function calls are equivalent.
+// If a View with this path is not found or View is not ListLayout, the function will return nil
+func ListLayoutByID(rootView View, id string, ids ...string) ListLayout {
+	if view := ViewByID(rootView, id, ids...); view != nil {
 		if list, ok := view.(ListLayout); ok {
 			return list
 		}
@@ -73,10 +94,15 @@ func ListLayoutByID(rootView View, id string) ListLayout {
 	return nil
 }
 
-// StackLayoutByID return a StackLayout with id equal to the argument of the function or
-// nil if there is no such View or View is not StackLayout
-func StackLayoutByID(rootView View, id string) StackLayout {
-	if view := ViewByID(rootView, id); view != nil {
+// StackLayoutByID return the StackLayout path to which is specified using the arguments id, ids. Example
+//
+//	view := StackLayoutByID(rootView, "id1", "id2", "id3")
+//	view := StackLayoutByID(rootView, "id1/id2/id3")
+//
+// These two function calls are equivalent.
+// If a View with this path is not found or View is not StackLayout, the function will return nil
+func StackLayoutByID(rootView View, id string, ids ...string) StackLayout {
+	if view := ViewByID(rootView, id, ids...); view != nil {
 		if list, ok := view.(StackLayout); ok {
 			return list
 		}
@@ -85,10 +111,15 @@ func StackLayoutByID(rootView View, id string) StackLayout {
 	return nil
 }
 
-// GridLayoutByID return a GridLayout with id equal to the argument of the function or
-// nil if there is no such View or View is not GridLayout
-func GridLayoutByID(rootView View, id string) GridLayout {
-	if view := ViewByID(rootView, id); view != nil {
+// GridLayoutByID return the GridLayout path to which is specified using the arguments id, ids. Example
+//
+//	view := GridLayoutByID(rootView, "id1", "id2", "id3")
+//	view := GridLayoutByID(rootView, "id1/id2/id3")
+//
+// These two function calls are equivalent.
+// If a View with this path is not found or View is not GridLayout, the function will return nil
+func GridLayoutByID(rootView View, id string, ids ...string) GridLayout {
+	if view := ViewByID(rootView, id, ids...); view != nil {
 		if list, ok := view.(GridLayout); ok {
 			return list
 		}
@@ -97,10 +128,15 @@ func GridLayoutByID(rootView View, id string) GridLayout {
 	return nil
 }
 
-// ColumnLayoutByID return a ColumnLayout with id equal to the argument of the function or
-// nil if there is no such View or View is not ColumnLayout
-func ColumnLayoutByID(rootView View, id string) ColumnLayout {
-	if view := ViewByID(rootView, id); view != nil {
+// ColumnLayoutByID return the ColumnLayout path to which is specified using the arguments id, ids. Example
+//
+//	view := ColumnLayoutByID(rootView, "id1", "id2", "id3")
+//	view := ColumnLayoutByID(rootView, "id1/id2/id3")
+//
+// These two function calls are equivalent.
+// If a View with this path is not found or View is not ColumnLayout, the function will return nil
+func ColumnLayoutByID(rootView View, id string, ids ...string) ColumnLayout {
+	if view := ViewByID(rootView, id, ids...); view != nil {
 		if list, ok := view.(ColumnLayout); ok {
 			return list
 		}
@@ -109,10 +145,15 @@ func ColumnLayoutByID(rootView View, id string) ColumnLayout {
 	return nil
 }
 
-// DetailsViewByID return a ColumnLayout with id equal to the argument of the function or
-// nil if there is no such View or View is not DetailsView
-func DetailsViewByID(rootView View, id string) DetailsView {
-	if view := ViewByID(rootView, id); view != nil {
+// DetailsViewByID return the ColumnLayout path to which is specified using the arguments id, ids. Example
+//
+//	view := DetailsViewByID(rootView, "id1", "id2", "id3")
+//	view := DetailsViewByID(rootView, "id1/id2/id3")
+//
+// These two function calls are equivalent.
+// If a View with this path is not found or View is not DetailsView, the function will return nil
+func DetailsViewByID(rootView View, id string, ids ...string) DetailsView {
+	if view := ViewByID(rootView, id, ids...); view != nil {
 		if details, ok := view.(DetailsView); ok {
 			return details
 		}
@@ -121,10 +162,15 @@ func DetailsViewByID(rootView View, id string) DetailsView {
 	return nil
 }
 
-// DropDownListByID return a DropDownListView with id equal to the argument of the function or
-// nil if there is no such View or View is not DropDownListView
-func DropDownListByID(rootView View, id string) DropDownList {
-	if view := ViewByID(rootView, id); view != nil {
+// DropDownListByID return the DropDownListView path to which is specified using the arguments id, ids. Example
+//
+//	view := DropDownListByID(rootView, "id1", "id2", "id3")
+//	view := DropDownListByID(rootView, "id1/id2/id3")
+//
+// These two function calls are equivalent.
+// If a View with this path is not found or View is not DropDownList, the function will return nil
+func DropDownListByID(rootView View, id string, ids ...string) DropDownList {
+	if view := ViewByID(rootView, id, ids...); view != nil {
 		if list, ok := view.(DropDownList); ok {
 			return list
 		}
@@ -133,10 +179,15 @@ func DropDownListByID(rootView View, id string) DropDownList {
 	return nil
 }
 
-// TabsLayoutByID return a TabsLayout with id equal to the argument of the function or
-// nil if there is no such View or View is not TabsLayout
-func TabsLayoutByID(rootView View, id string) TabsLayout {
-	if view := ViewByID(rootView, id); view != nil {
+// TabsLayoutByID return the TabsLayout path to which is specified using the arguments id, ids. Example
+//
+//	view := TabsLayoutByID(rootView, "id1", "id2", "id3")
+//	view := TabsLayoutByID(rootView, "id1/id2/id3")
+//
+// These two function calls are equivalent.
+// If a View with this path is not found or View is not TabsLayout, the function will return nil
+func TabsLayoutByID(rootView View, id string, ids ...string) TabsLayout {
+	if view := ViewByID(rootView, id, ids...); view != nil {
 		if list, ok := view.(TabsLayout); ok {
 			return list
 		}
@@ -145,10 +196,15 @@ func TabsLayoutByID(rootView View, id string) TabsLayout {
 	return nil
 }
 
-// ListViewByID return a ListView with id equal to the argument of the function or
-// nil if there is no such View or View is not ListView
-func ListViewByID(rootView View, id string) ListView {
-	if view := ViewByID(rootView, id); view != nil {
+// ListViewByID return the ListView path to which is specified using the arguments id, ids. Example
+//
+//	view := ListViewByID(rootView, "id1", "id2", "id3")
+//	view := ListViewByID(rootView, "id1/id2/id3")
+//
+// These two function calls are equivalent.
+// If a View with this path is not found or View is not ListView, the function will return nil
+func ListViewByID(rootView View, id string, ids ...string) ListView {
+	if view := ViewByID(rootView, id, ids...); view != nil {
 		if list, ok := view.(ListView); ok {
 			return list
 		}
@@ -157,10 +213,15 @@ func ListViewByID(rootView View, id string) ListView {
 	return nil
 }
 
-// TextViewByID return a TextView with id equal to the argument of the function or
-// nil if there is no such View or View is not TextView
-func TextViewByID(rootView View, id string) TextView {
-	if view := ViewByID(rootView, id); view != nil {
+// TextViewByID return the TextView path to which is specified using the arguments id, ids. Example
+//
+//	view := TextViewByID(rootView, "id1", "id2", "id3")
+//	view := TextViewByID(rootView, "id1/id2/id3")
+//
+// These two function calls are equivalent.
+// If a View with this path is not found or View is not TextView, the function will return nil
+func TextViewByID(rootView View, id string, ids ...string) TextView {
+	if view := ViewByID(rootView, id, ids...); view != nil {
 		if text, ok := view.(TextView); ok {
 			return text
 		}
@@ -169,10 +230,15 @@ func TextViewByID(rootView View, id string) TextView {
 	return nil
 }
 
-// ButtonByID return a Button with id equal to the argument of the function or
-// nil if there is no such View or View is not Button
-func ButtonByID(rootView View, id string) Button {
-	if view := ViewByID(rootView, id); view != nil {
+// ButtonByID return the Button path to which is specified using the arguments id, ids. Example
+//
+//	view := ButtonByID(rootView, "id1", "id2", "id3")
+//	view := ButtonByID(rootView, "id1/id2/id3")
+//
+// These two function calls are equivalent.
+// If a View with this path is not found or View is not Button, the function will return nil
+func ButtonByID(rootView View, id string, ids ...string) Button {
+	if view := ViewByID(rootView, id, ids...); view != nil {
 		if button, ok := view.(Button); ok {
 			return button
 		}
@@ -181,10 +247,15 @@ func ButtonByID(rootView View, id string) Button {
 	return nil
 }
 
-// CheckboxByID return a Checkbox with id equal to the argument of the function or
-// nil if there is no such View or View is not Checkbox
-func CheckboxByID(rootView View, id string) Checkbox {
-	if view := ViewByID(rootView, id); view != nil {
+// CheckboxByID return the Checkbox path to which is specified using the arguments id, ids. Example
+//
+//	view := CheckboxByID(rootView, "id1", "id2", "id3")
+//	view := CheckboxByID(rootView, "id1/id2/id3")
+//
+// These two function calls are equivalent.
+// If a View with this path is not found or View is not Checkbox, the function will return nil
+func CheckboxByID(rootView View, id string, ids ...string) Checkbox {
+	if view := ViewByID(rootView, id, ids...); view != nil {
 		if checkbox, ok := view.(Checkbox); ok {
 			return checkbox
 		}
@@ -193,10 +264,15 @@ func CheckboxByID(rootView View, id string) Checkbox {
 	return nil
 }
 
-// EditViewByID return a EditView with id equal to the argument of the function or
-// nil if there is no such View or View is not EditView
-func EditViewByID(rootView View, id string) EditView {
-	if view := ViewByID(rootView, id); view != nil {
+// EditViewByID return the EditView path to which is specified using the arguments id, ids. Example
+//
+//	view := EditViewByID(rootView, "id1", "id2", "id3")
+//	view := EditViewByID(rootView, "id1/id2/id3")
+//
+// These two function calls are equivalent.
+// If a View with this path is not found or View is not EditView, the function will return nil
+func EditViewByID(rootView View, id string, ids ...string) EditView {
+	if view := ViewByID(rootView, id, ids...); view != nil {
 		if buttons, ok := view.(EditView); ok {
 			return buttons
 		}
@@ -205,10 +281,15 @@ func EditViewByID(rootView View, id string) EditView {
 	return nil
 }
 
-// ProgressBarByID return a ProgressBar with id equal to the argument of the function or
-// nil if there is no such View or View is not ProgressBar
-func ProgressBarByID(rootView View, id string) ProgressBar {
-	if view := ViewByID(rootView, id); view != nil {
+// ProgressBarByID return the ProgressBar path to which is specified using the arguments id, ids. Example
+//
+//	view := ProgressBarByID(rootView, "id1", "id2", "id3")
+//	view := ProgressBarByID(rootView, "id1/id2/id3")
+//
+// These two function calls are equivalent.
+// If a View with this path is not found or View is not ProgressBar, the function will return nil
+func ProgressBarByID(rootView View, id string, ids ...string) ProgressBar {
+	if view := ViewByID(rootView, id, ids...); view != nil {
 		if buttons, ok := view.(ProgressBar); ok {
 			return buttons
 		}
@@ -217,10 +298,15 @@ func ProgressBarByID(rootView View, id string) ProgressBar {
 	return nil
 }
 
-// ColorPickerByID return a ColorPicker with id equal to the argument of the function or
-// nil if there is no such View or View is not ColorPicker
-func ColorPickerByID(rootView View, id string) ColorPicker {
-	if view := ViewByID(rootView, id); view != nil {
+// ColorPickerByID return the ColorPicker path to which is specified using the arguments id, ids. Example
+//
+//	view := ColorPickerByID(rootView, "id1", "id2", "id3")
+//	view := ColorPickerByID(rootView, "id1/id2/id3")
+//
+// These two function calls are equivalent.
+// If a View with this path is not found or View is not ColorPicker, the function will return nil
+func ColorPickerByID(rootView View, id string, ids ...string) ColorPicker {
+	if view := ViewByID(rootView, id, ids...); view != nil {
 		if input, ok := view.(ColorPicker); ok {
 			return input
 		}
@@ -229,10 +315,15 @@ func ColorPickerByID(rootView View, id string) ColorPicker {
 	return nil
 }
 
-// NumberPickerByID return a NumberPicker with id equal to the argument of the function or
-// nil if there is no such View or View is not NumberPicker
-func NumberPickerByID(rootView View, id string) NumberPicker {
-	if view := ViewByID(rootView, id); view != nil {
+// NumberPickerByID return the NumberPicker path to which is specified using the arguments id, ids. Example
+//
+//	view := NumberPickerByID(rootView, "id1", "id2", "id3")
+//	view := NumberPickerByID(rootView, "id1/id2/id3")
+//
+// These two function calls are equivalent.
+// If a View with this path is not found or View is not NumberPicker, the function will return nil
+func NumberPickerByID(rootView View, id string, ids ...string) NumberPicker {
+	if view := ViewByID(rootView, id, ids...); view != nil {
 		if input, ok := view.(NumberPicker); ok {
 			return input
 		}
@@ -241,10 +332,15 @@ func NumberPickerByID(rootView View, id string) NumberPicker {
 	return nil
 }
 
-// TimePickerByID return a TimePicker with id equal to the argument of the function or
-// nil if there is no such View or View is not TimePicker
-func TimePickerByID(rootView View, id string) TimePicker {
-	if view := ViewByID(rootView, id); view != nil {
+// TimePickerByID return the TimePicker path to which is specified using the arguments id, ids. Example
+//
+//	view := TimePickerByID(rootView, "id1", "id2", "id3")
+//	view := TimePickerByID(rootView, "id1/id2/id3")
+//
+// These two function calls are equivalent.
+// If a View with this path is not found or View is not TimePicker, the function will return nil
+func TimePickerByID(rootView View, id string, ids ...string) TimePicker {
+	if view := ViewByID(rootView, id, ids...); view != nil {
 		if input, ok := view.(TimePicker); ok {
 			return input
 		}
@@ -253,10 +349,15 @@ func TimePickerByID(rootView View, id string) TimePicker {
 	return nil
 }
 
-// DatePickerByID return a DatePicker with id equal to the argument of the function or
-// nil if there is no such View or View is not DatePicker
-func DatePickerByID(rootView View, id string) DatePicker {
-	if view := ViewByID(rootView, id); view != nil {
+// DatePickerByID return the DatePicker path to which is specified using the arguments id, ids. Example
+//
+//	view := DatePickerByID(rootView, "id1", "id2", "id3")
+//	view := DatePickerByID(rootView, "id1/id2/id3")
+//
+// These two function calls are equivalent.
+// If a View with this path is not found or View is not DatePicker, the function will return nil
+func DatePickerByID(rootView View, id string, ids ...string) DatePicker {
+	if view := ViewByID(rootView, id, ids...); view != nil {
 		if input, ok := view.(DatePicker); ok {
 			return input
 		}
@@ -265,10 +366,15 @@ func DatePickerByID(rootView View, id string) DatePicker {
 	return nil
 }
 
-// FilePickerByID return a FilePicker with id equal to the argument of the function or
-// nil if there is no such View or View is not FilePicker
-func FilePickerByID(rootView View, id string) FilePicker {
-	if view := ViewByID(rootView, id); view != nil {
+// FilePickerByID return the FilePicker path to which is specified using the arguments id, ids. Example
+//
+//	view := FilePickerByID(rootView, "id1", "id2", "id3")
+//	view := FilePickerByID(rootView, "id1/id2/id3")
+//
+// These two function calls are equivalent.
+// If a View with this path is not found or View is not FilePicker, the function will return nil
+func FilePickerByID(rootView View, id string, ids ...string) FilePicker {
+	if view := ViewByID(rootView, id, ids...); view != nil {
 		if input, ok := view.(FilePicker); ok {
 			return input
 		}
@@ -277,10 +383,15 @@ func FilePickerByID(rootView View, id string) FilePicker {
 	return nil
 }
 
-// CanvasViewByID return a CanvasView with id equal to the argument of the function or
-// nil if there is no such View or View is not CanvasView
-func CanvasViewByID(rootView View, id string) CanvasView {
-	if view := ViewByID(rootView, id); view != nil {
+// CanvasViewByID return the CanvasView path to which is specified using the arguments id, ids. Example
+//
+//	view := CanvasViewByID(rootView, "id1", "id2", "id3")
+//	view := CanvasViewByID(rootView, "id1/id2/id3")
+//
+// These two function calls are equivalent.
+// If a View with this path is not found or View is not CanvasView, the function will return nil
+func CanvasViewByID(rootView View, id string, ids ...string) CanvasView {
+	if view := ViewByID(rootView, id, ids...); view != nil {
 		if canvas, ok := view.(CanvasView); ok {
 			return canvas
 		}
@@ -289,24 +400,15 @@ func CanvasViewByID(rootView View, id string) CanvasView {
 	return nil
 }
 
-/*
-// TableViewByID return a TableView with id equal to the argument of the function or
-// nil if there is no such View or View is not TableView
-func TableViewByID(rootView View, id string) TableView {
-	if view := ViewByID(rootView, id); view != nil {
-		if canvas, ok := view.(TableView); ok {
-			return canvas
-		}
-		ErrorLog(`TableViewByID(_, "` + id + `"): The found View is not TableView`)
-	}
-	return nil
-}
-*/
-
-// AudioPlayerByID return a AudioPlayer with id equal to the argument of the function or
-// nil if there is no such View or View is not AudioPlayer
-func AudioPlayerByID(rootView View, id string) AudioPlayer {
-	if view := ViewByID(rootView, id); view != nil {
+// AudioPlayerByID return the AudioPlayer path to which is specified using the arguments id, ids. Example
+//
+//	view := AudioPlayerByID(rootView, "id1", "id2", "id3")
+//	view := AudioPlayerByID(rootView, "id1/id2/id3")
+//
+// These two function calls are equivalent.
+// If a View with this path is not found or View is not AudioPlayer, the function will return nil
+func AudioPlayerByID(rootView View, id string, ids ...string) AudioPlayer {
+	if view := ViewByID(rootView, id, ids...); view != nil {
 		if canvas, ok := view.(AudioPlayer); ok {
 			return canvas
 		}
@@ -315,10 +417,15 @@ func AudioPlayerByID(rootView View, id string) AudioPlayer {
 	return nil
 }
 
-// VideoPlayerByID return a VideoPlayer with id equal to the argument of the function or
-// nil if there is no such View or View is not VideoPlayer
-func VideoPlayerByID(rootView View, id string) VideoPlayer {
-	if view := ViewByID(rootView, id); view != nil {
+// VideoPlayerByID return the VideoPlayer path to which is specified using the arguments id, ids. Example
+//
+//	view := VideoPlayerByID(rootView, "id1", "id2", "id3")
+//	view := VideoPlayerByID(rootView, "id1/id2/id3")
+//
+// These two function calls are equivalent.
+// If a View with this path is not found or View is not VideoPlayer, the function will return nil
+func VideoPlayerByID(rootView View, id string, ids ...string) VideoPlayer {
+	if view := ViewByID(rootView, id, ids...); view != nil {
 		if canvas, ok := view.(VideoPlayer); ok {
 			return canvas
 		}
@@ -327,10 +434,15 @@ func VideoPlayerByID(rootView View, id string) VideoPlayer {
 	return nil
 }
 
-// ImageViewByID return a ImageView with id equal to the argument of the function or
-// nil if there is no such View or View is not ImageView
-func ImageViewByID(rootView View, id string) ImageView {
-	if view := ViewByID(rootView, id); view != nil {
+// ImageViewByID return the ImageView path to which is specified using the arguments id, ids. Example
+//
+//	view := ImageViewByID(rootView, "id1", "id2", "id3")
+//	view := ImageViewByID(rootView, "id1/id2/id3")
+//
+// These two function calls are equivalent.
+// If a View with this path is not found or View is not ImageView, the function will return nil
+func ImageViewByID(rootView View, id string, ids ...string) ImageView {
+	if view := ViewByID(rootView, id, ids...); view != nil {
 		if canvas, ok := view.(ImageView); ok {
 			return canvas
 		}
@@ -339,10 +451,15 @@ func ImageViewByID(rootView View, id string) ImageView {
 	return nil
 }
 
-// TableViewByID return a TableView with id equal to the argument of the function or
-// nil if there is no such View or View is not TableView
-func TableViewByID(rootView View, id string) TableView {
-	if view := ViewByID(rootView, id); view != nil {
+// TableViewByID return the TableView path to which is specified using the arguments id, ids. Example
+//
+//	view := TableViewByID(rootView, "id1", "id2", "id3")
+//	view := TableViewByID(rootView, "id1/id2/id3")
+//
+// These two function calls are equivalent.
+// If a View with this path is not found or View is not TableView, the function will return nil
+func TableViewByID(rootView View, id string, ids ...string) TableView {
+	if view := ViewByID(rootView, id, ids...); view != nil {
 		if canvas, ok := view.(TableView); ok {
 			return canvas
 		}

viewClip.go

@@ -1,584 +0,0 @@
-package rui
-
-import (
-	"fmt"
-	"strings"
-)
-
-// ClipShape defines a View clipping area
-type ClipShape interface {
-	Properties
-	fmt.Stringer
-	stringWriter
-	cssStyle(session Session) string
-	valid(session Session) bool
-}
-
-type insetClip struct {
-	propertyList
-}
-
-type ellipseClip struct {
-	propertyList
-}
-
-type circleClip struct {
-	propertyList
-}
-
-type polygonClip struct {
-	points []any
-}
-
-// InsetClip creates a rectangle View clipping area.
-// top - offset from the top border of a View;
-// right - offset from the right border of a View;
-// bottom - offset from the bottom border of a View;
-// left - offset from the left border of a View;
-// radius - corner radius, pass nil if you don't need to round corners
-func InsetClip(top, right, bottom, left SizeUnit, radius RadiusProperty) ClipShape {
-	clip := new(insetClip)
-	clip.init()
-	clip.Set(Top, top)
-	clip.Set(Right, right)
-	clip.Set(Bottom, bottom)
-	clip.Set(Left, left)
-	if radius != nil {
-		clip.Set(Radius, radius)
-	}
-	return clip
-}
-
-// CircleClip creates a circle View clipping area.
-func CircleClip(x, y, radius SizeUnit) ClipShape {
-	clip := new(circleClip)
-	clip.init()
-	clip.Set(X, x)
-	clip.Set(Y, y)
-	clip.Set(Radius, radius)
-	return clip
-}
-
-// EllipseClip creates a ellipse View clipping area.
-func EllipseClip(x, y, rx, ry SizeUnit) ClipShape {
-	clip := new(ellipseClip)
-	clip.init()
-	clip.Set(X, x)
-	clip.Set(Y, y)
-	clip.Set(RadiusX, rx)
-	clip.Set(RadiusY, ry)
-	return clip
-}
-
-// PolygonClip creates a polygon View clipping area.
-// The elements of the function argument can be or text constants,
-// or the text representation of SizeUnit, or elements of SizeUnit type.
-func PolygonClip(points []any) ClipShape {
-	clip := new(polygonClip)
-	clip.points = []any{}
-	if clip.Set(Points, points) {
-		return clip
-	}
-	return nil
-}
-
-// PolygonPointsClip creates a polygon View clipping area.
-func PolygonPointsClip(points []SizeUnit) ClipShape {
-	clip := new(polygonClip)
-	clip.points = []any{}
-	if clip.Set(Points, points) {
-		return clip
-	}
-	return nil
-}
-
-func (clip *insetClip) Set(tag string, value any) bool {
-	switch strings.ToLower(tag) {
-	case Top, Right, Bottom, Left:
-		if value == nil {
-			clip.Remove(tag)
-			return true
-		}
-		return clip.setSizeProperty(tag, value)
-
-	case Radius:
-		return clip.setRadius(value)
-
-	case RadiusX, RadiusY, RadiusTopLeft, RadiusTopLeftX, RadiusTopLeftY,
-		RadiusTopRight, RadiusTopRightX, RadiusTopRightY,
-		RadiusBottomLeft, RadiusBottomLeftX, RadiusBottomLeftY,
-		RadiusBottomRight, RadiusBottomRightX, RadiusBottomRightY:
-		return clip.setRadiusElement(tag, value)
-	}
-
-	ErrorLogF(`"%s" property is not supported by the inset clip shape`, tag)
-	return false
-}
-
-func (clip *insetClip) String() string {
-	return runStringWriter(clip)
-}
-
-func (clip *insetClip) writeString(buffer *strings.Builder, indent string) {
-	buffer.WriteString("inset { ")
-	comma := false
-	for _, tag := range []string{Top, Right, Bottom, Left, Radius} {
-		if value, ok := clip.properties[tag]; ok {
-			if comma {
-				buffer.WriteString(", ")
-			}
-			buffer.WriteString(tag)
-			buffer.WriteString(" = ")
-			writePropertyValue(buffer, tag, value, indent)
-			comma = true
-		}
-	}
-
-	buffer.WriteString(" }")
-}
-
-func (clip *insetClip) cssStyle(session Session) string {
-
-	buffer := allocStringBuilder()
-	defer freeStringBuilder(buffer)
-
-	leadText := "inset("
-	for _, tag := range []string{Top, Right, Bottom, Left} {
-		value, _ := sizeProperty(clip, tag, session)
-		buffer.WriteString(leadText)
-		buffer.WriteString(value.cssString("0px", session))
-		leadText = " "
-	}
-
-	if radius := getRadiusProperty(clip); radius != nil {
-		buffer.WriteString(" round ")
-		buffer.WriteString(radius.BoxRadius(session).cssString(session))
-	}
-
-	buffer.WriteRune(')')
-	return buffer.String()
-}
-
-func (clip *insetClip) valid(session Session) bool {
-	for _, tag := range []string{Top, Right, Bottom, Left, Radius, RadiusX, RadiusY} {
-		if value, ok := sizeProperty(clip, tag, session); ok && value.Type != Auto && value.Value != 0 {
-			return true
-		}
-	}
-	return false
-}
-
-func (clip *circleClip) Set(tag string, value any) bool {
-	if value == nil {
-		clip.Remove(tag)
-	}
-
-	switch strings.ToLower(tag) {
-	case X, Y, Radius:
-		return clip.setSizeProperty(tag, value)
-	}
-
-	ErrorLogF(`"%s" property is not supported by the circle clip shape`, tag)
-	return false
-}
-
-func (clip *circleClip) String() string {
-	return runStringWriter(clip)
-}
-
-func (clip *circleClip) writeString(buffer *strings.Builder, indent string) {
-	buffer.WriteString("circle { ")
-	comma := false
-	for _, tag := range []string{Radius, X, Y} {
-		if value, ok := clip.properties[tag]; ok {
-			if comma {
-				buffer.WriteString(", ")
-			}
-			buffer.WriteString(tag)
-			buffer.WriteString(" = ")
-			writePropertyValue(buffer, tag, value, indent)
-			comma = true
-		}
-	}
-
-	buffer.WriteString(" }")
-}
-
-func (clip *circleClip) cssStyle(session Session) string {
-
-	buffer := allocStringBuilder()
-	defer freeStringBuilder(buffer)
-
-	buffer.WriteString("circle(")
-	r, _ := sizeProperty(clip, Radius, session)
-	buffer.WriteString(r.cssString("50%", session))
-
-	buffer.WriteString(" at ")
-	x, _ := sizeProperty(clip, X, session)
-	buffer.WriteString(x.cssString("50%", session))
-	buffer.WriteRune(' ')
-
-	y, _ := sizeProperty(clip, Y, session)
-	buffer.WriteString(y.cssString("50%", session))
-	buffer.WriteRune(')')
-
-	return buffer.String()
-}
-
-func (clip *circleClip) valid(session Session) bool {
-	if value, ok := sizeProperty(clip, Radius, session); ok && value.Value == 0 {
-		return false
-	}
-	return true
-}
-
-func (clip *ellipseClip) Set(tag string, value any) bool {
-	if value == nil {
-		clip.Remove(tag)
-	}
-
-	switch strings.ToLower(tag) {
-	case X, Y, RadiusX, RadiusY:
-		return clip.setSizeProperty(tag, value)
-
-	case Radius:
-		return clip.setSizeProperty(RadiusX, value) &&
-			clip.setSizeProperty(RadiusY, value)
-	}
-
-	ErrorLogF(`"%s" property is not supported by the ellipse clip shape`, tag)
-	return false
-}
-
-func (clip *ellipseClip) String() string {
-	return runStringWriter(clip)
-}
-
-func (clip *ellipseClip) writeString(buffer *strings.Builder, indent string) {
-	buffer.WriteString("ellipse { ")
-	comma := false
-	for _, tag := range []string{RadiusX, RadiusY, X, Y} {
-		if value, ok := clip.properties[tag]; ok {
-			if comma {
-				buffer.WriteString(", ")
-			}
-			buffer.WriteString(tag)
-			buffer.WriteString(" = ")
-			writePropertyValue(buffer, tag, value, indent)
-			comma = true
-		}
-	}
-
-	buffer.WriteString(" }")
-}
-
-func (clip *ellipseClip) cssStyle(session Session) string {
-
-	buffer := allocStringBuilder()
-	defer freeStringBuilder(buffer)
-
-	rx, _ := sizeProperty(clip, RadiusX, session)
-	ry, _ := sizeProperty(clip, RadiusX, session)
-	buffer.WriteString("ellipse(")
-	buffer.WriteString(rx.cssString("50%", session))
-	buffer.WriteRune(' ')
-	buffer.WriteString(ry.cssString("50%", session))
-
-	buffer.WriteString(" at ")
-	x, _ := sizeProperty(clip, X, session)
-	buffer.WriteString(x.cssString("50%", session))
-	buffer.WriteRune(' ')
-
-	y, _ := sizeProperty(clip, Y, session)
-	buffer.WriteString(y.cssString("50%", session))
-	buffer.WriteRune(')')
-
-	return buffer.String()
-}
-
-func (clip *ellipseClip) valid(session Session) bool {
-	rx, _ := sizeProperty(clip, RadiusX, session)
-	ry, _ := sizeProperty(clip, RadiusY, session)
-	return rx.Value != 0 && ry.Value != 0
-}
-
-func (clip *polygonClip) Get(tag string) any {
-	if Points == strings.ToLower(tag) {
-		return clip.points
-	}
-	return nil
-}
-
-func (clip *polygonClip) getRaw(tag string) any {
-	return clip.Get(tag)
-}
-
-func (clip *polygonClip) Set(tag string, value any) bool {
-	if Points == strings.ToLower(tag) {
-		switch value := value.(type) {
-		case []any:
-			result := true
-			clip.points = make([]any, len(value))
-			for i, val := range value {
-				switch val := val.(type) {
-				case string:
-					if isConstantName(val) {
-						clip.points[i] = val
-					} else if size, ok := StringToSizeUnit(val); ok {
-						clip.points[i] = size
-					} else {
-						notCompatibleType(tag, val)
-						result = false
-					}
-
-				case SizeUnit:
-					clip.points[i] = val
-
-				default:
-					notCompatibleType(tag, val)
-					clip.points[i] = AutoSize()
-					result = false
-				}
-			}
-			return result
-
-		case []SizeUnit:
-			clip.points = make([]any, len(value))
-			for i, point := range value {
-				clip.points[i] = point
-			}
-			return true
-
-		case string:
-			result := true
-			values := strings.Split(value, ",")
-			clip.points = make([]any, len(values))
-			for i, val := range values {
-				val = strings.Trim(val, " \t\n\r")
-				if isConstantName(val) {
-					clip.points[i] = val
-				} else if size, ok := StringToSizeUnit(val); ok {
-					clip.points[i] = size
-				} else {
-					notCompatibleType(tag, val)
-					result = false
-				}
-			}
-			return result
-		}
-	}
-	return false
-}
-
-func (clip *polygonClip) setRaw(tag string, value any) {
-	clip.Set(tag, value)
-}
-
-func (clip *polygonClip) Remove(tag string) {
-	if Points == strings.ToLower(tag) {
-		clip.points = []any{}
-	}
-}
-
-func (clip *polygonClip) Clear() {
-	clip.points = []any{}
-}
-
-func (clip *polygonClip) AllTags() []string {
-	return []string{Points}
-}
-
-func (clip *polygonClip) String() string {
-	return runStringWriter(clip)
-}
-
-func (clip *polygonClip) writeString(buffer *strings.Builder, indent string) {
-
-	buffer.WriteString("inset { ")
-
-	if clip.points != nil {
-		buffer.WriteString(Points)
-		buffer.WriteString(` = "`)
-		for i, value := range clip.points {
-			if i > 0 {
-				buffer.WriteString(", ")
-			}
-			writePropertyValue(buffer, "", value, indent)
-		}
-
-		buffer.WriteString(`" `)
-	}
-
-	buffer.WriteRune('}')
-}
-
-func (clip *polygonClip) cssStyle(session Session) string {
-
-	count := len(clip.points)
-	if count < 2 {
-		return ""
-	}
-
-	buffer := allocStringBuilder()
-	defer freeStringBuilder(buffer)
-
-	writePoint := func(value any) {
-		switch value := value.(type) {
-		case string:
-			if val, ok := session.resolveConstants(value); ok {
-				if size, ok := StringToSizeUnit(val); ok {
-					buffer.WriteString(size.cssString("0px", session))
-					return
-				}
-			}
-
-		case SizeUnit:
-			buffer.WriteString(value.cssString("0px", session))
-			return
-		}
-
-		buffer.WriteString("0px")
-	}
-
-	leadText := "polygon("
-	for i := 1; i < count; i += 2 {
-		buffer.WriteString(leadText)
-		writePoint(clip.points[i-1])
-		buffer.WriteRune(' ')
-		writePoint(clip.points[i])
-		leadText = ", "
-	}
-
-	buffer.WriteRune(')')
-	return buffer.String()
-}
-
-func (clip *polygonClip) valid(session Session) bool {
-	if clip.points == nil || len(clip.points) == 0 {
-		return false
-	}
-
-	return true
-}
-
-func parseClipShape(obj DataObject) ClipShape {
-	switch obj.Tag() {
-	case "inset":
-		clip := new(insetClip)
-		for _, tag := range []string{Top, Right, Bottom, Left, Radius, RadiusX, RadiusY} {
-			if value, ok := obj.PropertyValue(tag); ok {
-				clip.Set(tag, value)
-			}
-		}
-		return clip
-
-	case "circle":
-		clip := new(ellipseClip)
-		for _, tag := range []string{X, Y, Radius} {
-			if value, ok := obj.PropertyValue(tag); ok {
-				clip.Set(tag, value)
-			}
-		}
-		return clip
-
-	case "ellipse":
-		clip := new(ellipseClip)
-		for _, tag := range []string{X, Y, RadiusX, RadiusY} {
-			if value, ok := obj.PropertyValue(tag); ok {
-				clip.Set(tag, value)
-			}
-		}
-		return clip
-
-	case "polygon":
-		clip := new(ellipseClip)
-		if value, ok := obj.PropertyValue(Points); ok {
-			clip.Set(Points, value)
-		}
-		return clip
-	}
-
-	return nil
-}
-
-func (style *viewStyle) setClipShape(tag string, value any) bool {
-	switch value := value.(type) {
-	case ClipShape:
-		style.properties[tag] = value
-		return true
-
-	case string:
-		if isConstantName(value) {
-			style.properties[tag] = value
-			return true
-		}
-
-		if obj := NewDataObject(value); obj == nil {
-			if clip := parseClipShape(obj); clip != nil {
-				style.properties[tag] = clip
-				return true
-			}
-		}
-
-	case DataObject:
-		if clip := parseClipShape(value); clip != nil {
-			style.properties[tag] = clip
-			return true
-		}
-
-	case DataValue:
-		if value.IsObject() {
-			if clip := parseClipShape(value.Object()); clip != nil {
-				style.properties[tag] = clip
-				return true
-			}
-		}
-	}
-
-	notCompatibleType(tag, value)
-	return false
-}
-
-func getClipShape(prop Properties, tag string, session Session) ClipShape {
-	if value := prop.getRaw(tag); value != nil {
-		switch value := value.(type) {
-		case ClipShape:
-			return value
-
-		case string:
-			if text, ok := session.resolveConstants(value); ok {
-				if obj := NewDataObject(text); obj == nil {
-					return parseClipShape(obj)
-				}
-			}
-		}
-	}
-
-	return nil
-}
-
-// GetClip returns a View clipping area.
-// If the second argument (subviewID) is not specified or it is "" then a top position of the first argument (view) is returned
-func GetClip(view View, subviewID ...string) ClipShape {
-	if len(subviewID) > 0 && subviewID[0] != "" {
-		view = ViewByID(view, subviewID[0])
-	}
-	if view != nil {
-		return getClipShape(view, Clip, view.Session())
-	}
-
-	return nil
-}
-
-// GetShapeOutside returns a shape around which adjacent inline content.
-// If the second argument (subviewID) is not specified or it is "" then a top position of the first argument (view) is returned
-func GetShapeOutside(view View, subviewID ...string) ClipShape {
-	if len(subviewID) > 0 && subviewID[0] != "" {
-		view = ViewByID(view, subviewID[0])
-	}
-	if view != nil {
-		return getClipShape(view, ShapeOutside, view.Session())
-	}
-
-	return nil
-}

viewFactory.go

@@ -85,6 +85,7 @@ func CreateViewFromObject(session Session, object DataObject) View {
 			defer session.setIgnoreViewUpdates(false)
 		}
 		view := creator(session)
+		view.init(session)
 		if customView, ok := view.(CustomView); ok {
 			if !InitCustomView(customView, tag, session, nil) {
 				return nil

viewFilter.go

@@ -1,305 +0,0 @@
-package rui
-
-import (
-	"fmt"
-	"strings"
-)
-
-const (
-	// Blur is the constant for the "blur" property tag of the ViewFilter interface.
-	// The "blur" float64 property applies a Gaussian blur. The value of radius defines the value
-	// of the standard deviation to the Gaussian function, or how many pixels on the screen blend
-	// into each other, so a larger value will create more blur. The lacuna value for interpolation is 0.
-	// The parameter is specified as a length in pixels.
-	Blur = "blur"
-
-	// Brightness is the constant for the "brightness" property tag of the ViewFilter interface.
-	// The "brightness" float64 property applies a linear multiplier to input image, making it appear more
-	// or less bright. A value of 0% will create an image that is completely black.
-	// A value of 100% leaves the input unchanged. Other values are linear multipliers on the effect.
-	// Values of an amount over 100% are allowed, providing brighter results.
-	Brightness = "brightness"
-
-	// Contrast is the constant for the "contrast" property tag of the ViewFilter interface.
-	// The "contrast" float64 property adjusts the contrast of the input.
-	// A value of 0% will create an image that is completely black. A value of 100% leaves the input unchanged.
-	// Values of amount over 100% are allowed, providing results with less contrast.
-	Contrast = "contrast"
-
-	// DropShadow is the constant for the "drop-shadow" property tag of the ViewFilter interface.
-	// The "drop-shadow" property applies a drop shadow effect to the input image.
-	// A drop shadow is effectively a blurred, offset version of the input image's alpha mask
-	// drawn in a particular color, composited below the image.
-	// Shadow parameters are set using the ViewShadow interface
-	DropShadow = "drop-shadow"
-
-	// Grayscale is the constant for the "grayscale" property tag of the ViewFilter interface.
-	// The "grayscale" float64 property converts the input image to grayscale.
-	// The value of ‘amount’ defines the proportion of the conversion.
-	// A value of 100% is completely grayscale. A value of 0% leaves the input unchanged.
-	// Values between 0% and 100% are linear multipliers on the effect.
-	Grayscale = "grayscale"
-
-	// HueRotate is the constant for the "hue-rotate" property tag of the ViewFilter interface.
-	// The "hue-rotate" AngleUnit property applies a hue rotation on the input image.
-	// The value of ‘angle’ defines the number of degrees around the color circle the input samples will be adjusted.
-	// A value of 0deg leaves the input unchanged. If the ‘angle’ parameter is missing, a value of 0deg is used.
-	// Though there is no maximum value, the effect of values above 360deg wraps around.
-	HueRotate = "hue-rotate"
-
-	// Invert is the constant for the "invert" property tag of the ViewFilter interface.
-	// The "invert" float64 property inverts the samples in the input image.
-	// The value of ‘amount’ defines the proportion of the conversion.
-	// A value of 100% is completely inverted. A value of 0% leaves the input unchanged.
-	// Values between 0% and 100% are linear multipliers on the effect.
-	Invert = "invert"
-
-	// Saturate is the constant for the "saturate" property tag of the ViewFilter interface.
-	// The "saturate" float64 property saturates the input image.
-	// The value of ‘amount’ defines the proportion of the conversion.
-	// A value of 0% is completely un-saturated. A value of 100% leaves the input unchanged.
-	// Other values are linear multipliers on the effect.
-	// Values of amount over 100% are allowed, providing super-saturated results.
-	Saturate = "saturate"
-
-	// Sepia is the constant for the "sepia" property tag of the ViewFilter interface.
-	// The "sepia" float64 property converts the input image to sepia.
-	// The value of ‘amount’ defines the proportion of the conversion.
-	// A value of 100% is completely sepia. A value of 0% leaves the input unchanged.
-	// Values between 0% and 100% are linear multipliers on the effect.
-	Sepia = "sepia"
-
-	//Opacity = "opacity"
-)
-
-// ViewFilter defines an applied to a View a graphical effects like blur or color shift.
-// Allowable properties are Blur, Brightness, Contrast, DropShadow, Grayscale, HueRotate, Invert, Opacity, Saturate, and Sepia
-type ViewFilter interface {
-	Properties
-	fmt.Stringer
-	stringWriter
-	cssStyle(session Session) string
-}
-
-type viewFilter struct {
-	propertyList
-}
-
-// NewViewFilter creates the new ViewFilter
-func NewViewFilter(params Params) ViewFilter {
-	if params != nil {
-		filter := new(viewFilter)
-		filter.init()
-		for tag, value := range params {
-			filter.Set(tag, value)
-		}
-		if len(filter.properties) > 0 {
-			return filter
-		}
-	}
-	return nil
-}
-
-func newViewFilter(obj DataObject) ViewFilter {
-	filter := new(viewFilter)
-	filter.init()
-	for i := 0; i < obj.PropertyCount(); i++ {
-		if node := obj.Property(i); node != nil {
-			tag := node.Tag()
-			switch node.Type() {
-			case TextNode:
-				filter.Set(tag, node.Text())
-
-			case ObjectNode:
-				if tag == HueRotate {
-					// TODO
-				} else {
-					ErrorLog(`Invalid value of "` + tag + `"`)
-				}
-
-			default:
-				ErrorLog(`Invalid value of "` + tag + `"`)
-			}
-		}
-	}
-
-	if len(filter.properties) > 0 {
-		return filter
-	}
-	ErrorLog("Empty view filter")
-	return nil
-}
-
-func (filter *viewFilter) Set(tag string, value any) bool {
-	if value == nil {
-		filter.Remove(tag)
-		return true
-	}
-
-	switch strings.ToLower(tag) {
-	case Blur, Brightness, Contrast, Saturate:
-		return filter.setFloatProperty(tag, value, 0, 10000)
-
-	case Grayscale, Invert, Opacity, Sepia:
-		return filter.setFloatProperty(tag, value, 0, 100)
-
-	case HueRotate:
-		return filter.setAngleProperty(tag, value)
-
-	case DropShadow:
-		return filter.setShadow(tag, value)
-	}
-
-	ErrorLogF(`"%s" property is not supported by the view filter`, tag)
-	return false
-}
-
-func (filter *viewFilter) String() string {
-	return runStringWriter(filter)
-}
-
-func (filter *viewFilter) writeString(buffer *strings.Builder, indent string) {
-	buffer.WriteString("filter { ")
-	comma := false
-	tags := filter.AllTags()
-	for _, tag := range tags {
-		if value, ok := filter.properties[tag]; ok {
-			if comma {
-				buffer.WriteString(", ")
-			}
-			buffer.WriteString(tag)
-			buffer.WriteString(" = ")
-			writePropertyValue(buffer, tag, value, indent)
-			comma = true
-		}
-	}
-	buffer.WriteString(" }")
-}
-
-func (filter *viewFilter) cssStyle(session Session) string {
-	buffer := allocStringBuilder()
-	defer freeStringBuilder(buffer)
-
-	if value, ok := floatTextProperty(filter, Blur, session, 0); ok {
-		buffer.WriteString(Blur)
-		buffer.WriteRune('(')
-		buffer.WriteString(value)
-		buffer.WriteString("px)")
-	}
-
-	for _, tag := range []string{Brightness, Contrast, Saturate, Grayscale, Invert, Opacity, Sepia} {
-		if value, ok := floatTextProperty(filter, tag, session, 0); ok {
-			if buffer.Len() > 0 {
-				buffer.WriteRune(' ')
-			}
-			buffer.WriteString(tag)
-			buffer.WriteRune('(')
-			buffer.WriteString(value)
-			buffer.WriteString("%)")
-		}
-	}
-
-	if value, ok := angleProperty(filter, HueRotate, session); ok {
-		if buffer.Len() > 0 {
-			buffer.WriteRune(' ')
-		}
-		buffer.WriteString(HueRotate)
-		buffer.WriteRune('(')
-		buffer.WriteString(value.cssString())
-		buffer.WriteRune(')')
-	}
-
-	var lead string
-	if buffer.Len() > 0 {
-		lead = " drop-shadow("
-	} else {
-		lead = "drop-shadow("
-	}
-
-	for _, shadow := range getShadows(filter, DropShadow) {
-		if shadow.cssTextStyle(buffer, session, lead) {
-			buffer.WriteRune(')')
-			lead = " drop-shadow("
-		}
-	}
-
-	return buffer.String()
-}
-
-func (style *viewStyle) setFilter(tag string, value any) bool {
-	switch value := value.(type) {
-	case ViewFilter:
-		style.properties[tag] = value
-		return true
-
-	case string:
-		if obj := NewDataObject(value); obj == nil {
-			if filter := newViewFilter(obj); filter != nil {
-				style.properties[tag] = filter
-				return true
-			}
-		}
-	case DataObject:
-		if filter := newViewFilter(value); filter != nil {
-			style.properties[tag] = filter
-			return true
-		}
-
-	case DataValue:
-		if value.IsObject() {
-			if filter := newViewFilter(value.Object()); filter != nil {
-				style.properties[tag] = filter
-				return true
-			}
-		}
-	}
-
-	notCompatibleType(tag, value)
-	return false
-}
-
-// GetFilter returns a View graphical effects like blur or color shift.
-// If the second argument (subviewID) is not specified or it is "" then a top position of the first argument (view) is returned
-func GetFilter(view View, subviewID ...string) ViewFilter {
-	if len(subviewID) > 0 && subviewID[0] != "" {
-		view = ViewByID(view, subviewID[0])
-	}
-
-	if view != nil {
-		if value := view.getRaw(Filter); value != nil {
-			if filter, ok := value.(ViewFilter); ok {
-				return filter
-			}
-		}
-		if value := valueFromStyle(view, Filter); value != nil {
-			if filter, ok := value.(ViewFilter); ok {
-				return filter
-			}
-		}
-	}
-
-	return nil
-}
-
-// GetBackdropFilter returns the area behind a View graphical effects like blur or color shift.
-// If the second argument (subviewID) is not specified or it is "" then a top position of the first argument (view) is returned
-func GetBackdropFilter(view View, subviewID ...string) ViewFilter {
-	if len(subviewID) > 0 && subviewID[0] != "" {
-		view = ViewByID(view, subviewID[0])
-	}
-
-	if view != nil {
-		if value := view.getRaw(BackdropFilter); value != nil {
-			if filter, ok := value.(ViewFilter); ok {
-				return filter
-			}
-		}
-		if value := valueFromStyle(view, BackdropFilter); value != nil {
-			if filter, ok := value.(ViewFilter); ok {
-				return filter
-			}
-		}
-	}
-
-	return nil
-}

viewStyle.go

@@ -12,72 +12,31 @@ type ViewStyle interface {
 	Properties
 
 	// Transition returns the transition animation of the property. Returns nil is there is no transition animation.
-	Transition(tag string) Animation
+	Transition(tag PropertyName) AnimationProperty
 
 	// Transitions returns the map of transition animations. The result is always non-nil.
-	Transitions() map[string]Animation
+	Transitions() map[PropertyName]AnimationProperty
 
 	// SetTransition sets the transition animation for the property if "animation" argument is not nil, and
 	// removes the transition animation of the property if "animation" argument  is nil.
 	// The "tag" argument is the property name.
-	SetTransition(tag string, animation Animation)
+	SetTransition(tag PropertyName, animation AnimationProperty)
 
 	cssViewStyle(buffer cssBuilder, session Session)
 }
 
 type viewStyle struct {
 	propertyList
-	transitions map[string]Animation
-}
-
-// Range defines range limits. The First and Last value are included in the range
-type Range struct {
-	First, Last int
+	//transitions map[PropertyName]Animation
 }
 
 type stringWriter interface {
 	writeString(buffer *strings.Builder, indent string)
 }
 
-// String returns a string representation of the Range struct
-func (r Range) String() string {
-	if r.First == r.Last {
-		return fmt.Sprintf("%d", r.First)
-	}
-	return fmt.Sprintf("%d:%d", r.First, r.Last)
-}
-
-func (r *Range) setValue(value string) bool {
-	var err error
-	if strings.Contains(value, ":") {
-		values := strings.Split(value, ":")
-		if len(values) != 2 {
-			ErrorLog("Invalid range value: " + value)
-			return false
-		}
-		if r.First, err = strconv.Atoi(strings.Trim(values[0], " \t\n\r")); err != nil {
-			ErrorLog(`Invalid first range value "` + value + `" (` + err.Error() + ")")
-			return false
-		}
-		if r.Last, err = strconv.Atoi(strings.Trim(values[1], " \t\n\r")); err != nil {
-			ErrorLog(`Invalid last range value "` + value + `" (` + err.Error() + ")")
-			return false
-		}
-		return true
-	}
-
-	if r.First, err = strconv.Atoi(value); err != nil {
-		ErrorLog(`Invalid range value "` + value + `" (` + err.Error() + ")")
-		return false
-	}
-	r.Last = r.First
-	return true
-}
-
 func (style *viewStyle) init() {
 	style.propertyList.init()
-	//style.shadows = []ViewShadow{}
-	style.transitions = map[string]Animation{}
+	style.normalize = normalizeViewStyleTag
 }
 
 // NewViewStyle create new ViewStyle object
@@ -90,19 +49,19 @@ func NewViewStyle(params Params) ViewStyle {
 	return style
 }
 
-func (style *viewStyle) cssTextDecoration(session Session) string {
+func textDecorationCSS(properties Properties, session Session) string {
 	buffer := allocStringBuilder()
 	defer freeStringBuilder(buffer)
 
 	noDecoration := false
-	if strikethrough, ok := boolProperty(style, Strikethrough, session); ok {
+	if strikethrough, ok := boolProperty(properties, Strikethrough, session); ok {
 		if strikethrough {
 			buffer.WriteString("line-through")
 		}
 		noDecoration = true
 	}
 
-	if overline, ok := boolProperty(style, Overline, session); ok {
+	if overline, ok := boolProperty(properties, Overline, session); ok {
 		if overline {
 			if buffer.Len() > 0 {
 				buffer.WriteRune(' ')
@@ -112,7 +71,7 @@ func (style *viewStyle) cssTextDecoration(session Session) string {
 		noDecoration = true
 	}
 
-	if underline, ok := boolProperty(style, Underline, session); ok {
+	if underline, ok := boolProperty(properties, Underline, session); ok {
 		if underline {
 			if buffer.Len() > 0 {
 				buffer.WriteRune(' ')
@@ -149,40 +108,27 @@ func split4Values(text string) []string {
 	return []string{}
 }
 
-func (style *viewStyle) backgroundCSS(session Session) string {
-	if value, ok := style.properties[Background]; ok {
-		if backgrounds, ok := value.([]BackgroundElement); ok {
-			buffer := allocStringBuilder()
-			defer freeStringBuilder(buffer)
-
-			for _, background := range backgrounds {
-				if value := background.cssStyle(session); value != "" {
-					if buffer.Len() > 0 {
-						buffer.WriteString(", ")
-					}
-					buffer.WriteString(value)
-				}
-			}
-
-			if buffer.Len() > 0 {
-				return buffer.String()
-			}
-		}
-	}
-	return ""
-}
-
 func (style *viewStyle) cssViewStyle(builder cssBuilder, session Session) {
 
-	if margin, ok := boundsProperty(style, Margin, session); ok {
+	if visibility, ok := enumProperty(style, Visibility, session, Visible); ok {
+		switch visibility {
+		case Invisible:
+			builder.add(`visibility`, `hidden`)
+
+		case Gone:
+			builder.add(`display`, `none`)
+		}
+	}
+
+	if margin, ok := getBounds(style, Margin, session); ok {
 		margin.cssValue(Margin, builder, session)
 	}
 
-	if padding, ok := boundsProperty(style, Padding, session); ok {
+	if padding, ok := getBounds(style, Padding, session); ok {
 		padding.cssValue(Padding, builder, session)
 	}
 
-	if border := getBorder(style, Border); border != nil {
+	if border := getBorderProperty(style, Border); border != nil {
 		border.cssStyle(builder, session)
 		border.cssWidth(builder, session)
 		border.cssColor(builder, session)
@@ -191,27 +137,27 @@ func (style *viewStyle) cssViewStyle(builder cssBuilder, session Session) {
 	radius := getRadius(style, session)
 	radius.cssValue(builder, session)
 
-	if outline := getOutline(style); outline != nil {
+	if outline := getOutlineProperty(style); outline != nil {
 		outline.ViewOutline(session).cssValue(builder, session)
 	}
 
-	for _, tag := range []string{ZIndex, Order} {
+	for _, tag := range []PropertyName{ZIndex, Order} {
 		if value, ok := intProperty(style, tag, session, 0); ok {
-			builder.add(tag, strconv.Itoa(value))
+			builder.add(string(tag), strconv.Itoa(value))
 		}
 	}
 
 	if opacity, ok := floatProperty(style, Opacity, session, 1.0); ok && opacity >= 0 && opacity <= 1 {
-		builder.add(Opacity, strconv.FormatFloat(opacity, 'f', 3, 32))
+		builder.add(string(Opacity), strconv.FormatFloat(opacity, 'f', 3, 32))
 	}
 
-	for _, tag := range []string{ColumnCount, TabSize} {
+	for _, tag := range []PropertyName{ColumnCount, TabSize} {
 		if value, ok := intProperty(style, tag, session, 0); ok && value > 0 {
-			builder.add(tag, strconv.Itoa(value))
+			builder.add(string(tag), strconv.Itoa(value))
 		}
 	}
 
-	for _, tag := range []string{
+	for _, tag := range []PropertyName{
 		Width, Height, MinWidth, MinHeight, MaxWidth, MaxHeight, Left, Right, Top, Bottom,
 		TextSize, TextIndent, LetterSpacing, WordSpacing, LineHeight, TextLineThickness,
 		ListRowGap, ListColumnGap, GridRowGap, GridColumnGap, ColumnGap, ColumnWidth, OutlineOffset} {
@@ -219,18 +165,22 @@ func (style *viewStyle) cssViewStyle(builder cssBuilder, session Session) {
 		if size, ok := sizeProperty(style, tag, session); ok && size.Type != Auto {
 			cssTag, ok := sizeProperties[tag]
 			if !ok {
-				cssTag = tag
+				cssTag = string(tag)
 			}
 			builder.add(cssTag, size.cssString("", session))
 		}
 	}
 
-	colorProperties := []struct{ property, cssTag string }{
-		{BackgroundColor, BackgroundColor},
+	type propertyCss struct {
+		property PropertyName
+		cssTag   string
+	}
+	colorProperties := []propertyCss{
+		//{BackgroundColor, string(BackgroundColor)},
 		{TextColor, "color"},
 		{TextLineColor, "text-decoration-color"},
-		{CaretColor, CaretColor},
-		{AccentColor, AccentColor},
+		{CaretColor, string(CaretColor)},
+		{AccentColor, string(AccentColor)},
 	}
 	for _, p := range colorProperties {
 		if color, ok := colorProperty(style, p.property, session); ok && color != 0 {
@@ -238,12 +188,25 @@ func (style *viewStyle) cssViewStyle(builder cssBuilder, session Session) {
 		}
 	}
 
-	if value, ok := enumProperty(style, BackgroundClip, session, 0); ok {
-		builder.add(BackgroundClip, enumProperties[BackgroundClip].values[value])
+	for _, tag := range []PropertyName{BackgroundClip, BackgroundOrigin, MaskClip, MaskOrigin} {
+		if value, ok := enumProperty(style, tag, session, 0); ok {
+			if data, ok := enumProperties[tag]; ok {
+				builder.add(data.cssTag, data.cssValues[value])
+			}
+		}
 	}
 
-	if background := style.backgroundCSS(session); background != "" {
+	if background := backgroundCSS(style, session); background != "" {
 		builder.add("background", background)
+	} else {
+		backgroundColor, _ := colorProperty(style, BackgroundColor, session)
+		if backgroundColor != 0 {
+			builder.add("background-color", backgroundColor.cssString())
+		}
+	}
+
+	if mask := maskCSS(style, session); mask != "" {
+		builder.add("mask", mask)
 	}
 
 	if font, ok := stringProperty(style, FontName, session); ok && font != "" {
@@ -251,7 +214,7 @@ func (style *viewStyle) cssViewStyle(builder cssBuilder, session Session) {
 	}
 
 	writingMode := 0
-	for _, tag := range []string{
+	for _, tag := range []PropertyName{
 		Overflow, TextAlign, TextTransform, TextWeight, TextLineStyle, WritingMode, TextDirection,
 		VerticalTextOrientation, CellVerticalAlign, CellHorizontalAlign, GridAutoFlow, Cursor,
 		WhiteSpace, WordBreak, TextOverflow, Float, TableVerticalAlign, Resize, MixBlendMode, BackgroundBlendMode} {
@@ -272,7 +235,11 @@ func (style *viewStyle) cssViewStyle(builder cssBuilder, session Session) {
 		}
 	}
 
-	for _, prop := range []struct{ tag, cssTag, off, on string }{
+	type boolPropertyCss struct {
+		tag             PropertyName
+		cssTag, off, on string
+	}
+	for _, prop := range []boolPropertyCss{
 		{tag: Italic, cssTag: "font-style", off: "normal", on: "italic"},
 		{tag: SmallCaps, cssTag: "font-variant", off: "normal", on: "small-caps"},
 	} {
@@ -285,7 +252,7 @@ func (style *viewStyle) cssViewStyle(builder cssBuilder, session Session) {
 		}
 	}
 
-	if text := style.cssTextDecoration(session); text != "" {
+	if text := textDecorationCSS(style, session); text != "" {
 		builder.add("text-decoration", text)
 	}
 
@@ -406,46 +373,46 @@ func (style *viewStyle) cssViewStyle(builder cssBuilder, session Session) {
 	if r, ok := rangeProperty(style, Column, session); ok {
 		builder.add("grid-column", fmt.Sprintf("%d / %d", r.First+1, r.Last+2))
 	}
-	if text := style.gridCellSizesCSS(CellWidth, session); text != "" {
+	if text := gridCellSizesCSS(style, CellWidth, session); text != "" {
 		builder.add(`grid-template-columns`, text)
 	}
-	if text := style.gridCellSizesCSS(CellHeight, session); text != "" {
+	if text := gridCellSizesCSS(style, CellHeight, session); text != "" {
 		builder.add(`grid-template-rows`, text)
 	}
 
 	style.writeViewTransformCSS(builder, session)
 
-	if clip := getClipShape(style, Clip, session); clip != nil && clip.valid(session) {
+	if clip := getClipShapeProperty(style, Clip, session); clip != nil && clip.valid(session) {
 		builder.add(`clip-path`, clip.cssStyle(session))
 	}
 
-	if clip := getClipShape(style, ShapeOutside, session); clip != nil && clip.valid(session) {
+	if clip := getClipShapeProperty(style, ShapeOutside, session); clip != nil && clip.valid(session) {
 		builder.add(`shape-outside`, clip.cssStyle(session))
 	}
 
 	if value := style.getRaw(Filter); value != nil {
-		if filter, ok := value.(ViewFilter); ok {
+		if filter, ok := value.(FilterProperty); ok {
 			if text := filter.cssStyle(session); text != "" {
-				builder.add(Filter, text)
+				builder.add(string(Filter), text)
 			}
 		}
 	}
 
 	if value := style.getRaw(BackdropFilter); value != nil {
-		if filter, ok := value.(ViewFilter); ok {
+		if filter, ok := value.(FilterProperty); ok {
 			if text := filter.cssStyle(session); text != "" {
 				builder.add(`-webkit-backdrop-filter`, text)
-				builder.add(BackdropFilter, text)
+				builder.add(string(BackdropFilter), text)
 			}
 		}
 	}
 
-	if transition := style.transitionCSS(session); transition != "" {
+	if transition := transitionCSS(style, session); transition != "" {
 		builder.add(`transition`, transition)
 	}
 
-	if animation := style.animationCSS(session); animation != "" {
-		builder.add(AnimationTag, animation)
+	if animation := animationCSS(style, session); animation != "" {
+		builder.add(string(Animation), animation)
 	}
 
 	if pause, ok := boolProperty(style, AnimationPaused, session); ok {
@@ -494,20 +461,58 @@ func valueToOrientation(value any, session Session) (int, bool) {
 	return 0, false
 }
 
-func (style *viewStyle) Get(tag string) any {
-	return style.get(strings.ToLower(tag))
+func normalizeViewStyleTag(tag PropertyName) PropertyName {
+	tag = defaultNormalize(tag)
+	switch tag {
+	case "top-margin":
+		return MarginTop
+
+	case "right-margin":
+		return MarginRight
+
+	case "bottom-margin":
+		return MarginBottom
+
+	case "left-margin":
+		return MarginLeft
+
+	case "top-padding":
+		return PaddingTop
+
+	case "right-padding":
+		return PaddingRight
+
+	case "bottom-padding":
+		return PaddingBottom
+
+	case "left-padding":
+		return PaddingLeft
+
+	case "origin-x":
+		return TransformOriginX
+
+	case "origin-y":
+		return TransformOriginY
+
+	case "origin-z":
+		return TransformOriginZ
+
+	}
+	return tag
 }
 
-func (style *viewStyle) get(tag string) any {
+func (style *viewStyle) Get(tag PropertyName) any {
+	return viewStyleGet(style, normalizeViewStyleTag(tag))
+}
+
+func viewStyleGet(style Properties, tag PropertyName) any {
 	switch tag {
-	case Border, CellBorder:
-		return getBorder(&style.propertyList, tag)
 
 	case BorderLeft, BorderRight, BorderTop, BorderBottom,
 		BorderStyle, BorderLeftStyle, BorderRightStyle, BorderTopStyle, BorderBottomStyle,
 		BorderColor, BorderLeftColor, BorderRightColor, BorderTopColor, BorderBottomColor,
 		BorderWidth, BorderLeftWidth, BorderRightWidth, BorderTopWidth, BorderBottomWidth:
-		if border := getBorder(style, Border); border != nil {
+		if border := getBorderProperty(style, Border); border != nil {
 			return border.Get(tag)
 		}
 		return nil
@@ -516,7 +521,7 @@ func (style *viewStyle) get(tag string) any {
 		CellBorderStyle, CellBorderLeftStyle, CellBorderRightStyle, CellBorderTopStyle, CellBorderBottomStyle,
 		CellBorderColor, CellBorderLeftColor, CellBorderRightColor, CellBorderTopColor, CellBorderBottomColor,
 		CellBorderWidth, CellBorderLeftWidth, CellBorderRightWidth, CellBorderTopWidth, CellBorderBottomWidth:
-		if border := getBorder(style, CellBorder); border != nil {
+		if border := getBorderProperty(style, CellBorder); border != nil {
 			return border.Get(tag)
 		}
 		return nil
@@ -527,39 +532,22 @@ func (style *viewStyle) get(tag string) any {
 		RadiusBottomRight, RadiusBottomRightX, RadiusBottomRightY:
 		return getRadiusElement(style, tag)
 
-	case ColumnSeparator:
-		if val, ok := style.properties[ColumnSeparator]; ok {
-			return val.(ColumnSeparatorProperty)
-		}
-		return nil
-
 	case ColumnSeparatorStyle, ColumnSeparatorWidth, ColumnSeparatorColor:
-		if val, ok := style.properties[ColumnSeparator]; ok {
+		if val := style.getRaw(ColumnSeparator); val != nil {
 			separator := val.(ColumnSeparatorProperty)
 			return separator.Get(tag)
 		}
 		return nil
 
-	case Transition:
-		if len(style.transitions) == 0 {
-			return nil
+	case RotateX, RotateY, RotateZ, Rotate, SkewX, SkewY, ScaleX, ScaleY, ScaleZ,
+		TranslateX, TranslateY, TranslateZ:
+		if transform := getTransformProperty(style, Transform); transform != nil {
+			return transform.Get(tag)
 		}
-		result := map[string]Animation{}
-		for tag, animation := range style.transitions {
-			result[tag] = animation
-		}
-		return result
+		return nil
 	}
 
-	return style.propertyList.getRaw(tag)
-}
-
-func (style *viewStyle) AllTags() []string {
-	result := style.propertyList.AllTags()
-	if len(style.transitions) > 0 {
-		result = append(result, Transition)
-	}
-	return result
+	return style.getRaw(tag)
 }
 
 func supportedPropertyValue(value any) bool {
@@ -572,20 +560,20 @@ func supportedPropertyValue(value any) bool {
 	case int:
 	case stringWriter:
 	case fmt.Stringer:
-	case []ViewShadow:
+	case []ShadowProperty:
 	case []View:
 	case []any:
 	case []BackgroundElement:
 	case []BackgroundGradientPoint:
 	case []BackgroundGradientAngle:
-	case map[string]Animation:
+	case map[PropertyName]AnimationProperty:
 	default:
 		return false
 	}
 	return true
 }
 
-func writePropertyValue(buffer *strings.Builder, tag string, value any, indent string) {
+func writePropertyValue(buffer *strings.Builder, tag PropertyName, value any, indent string) {
 
 	writeString := func(text string) {
 		simple := (tag != Text && tag != Title && tag != Summary)
@@ -595,8 +583,8 @@ func writePropertyValue(buffer *strings.Builder, tag string, value any, indent s
 			} else {
 				for _, ch := range text {
 					if (ch >= '0' && ch <= '9') || (ch >= 'A' && ch <= 'Z') || (ch >= 'a' && ch <= 'z') ||
-						ch == '+' || ch == '-' || ch == '@' || ch == '/' || ch == '_' || ch == ':' ||
-						ch == '#' || ch == '%' || ch == 'π' || ch == '°' {
+						ch == '+' || ch == '-' || ch == '@' || ch == '/' || ch == '_' || ch == '.' ||
+						ch == ':' || ch == '#' || ch == '%' || ch == 'π' || ch == '°' {
 					} else {
 						simple = false
 						break
@@ -683,7 +671,7 @@ func writePropertyValue(buffer *strings.Builder, tag string, value any, indent s
 	case fmt.Stringer:
 		writeString(value.String())
 
-	case []ViewShadow:
+	case []ShadowProperty:
 		switch len(value) {
 		case 0:
 			// do nothing
@@ -787,7 +775,7 @@ func writePropertyValue(buffer *strings.Builder, tag string, value any, indent s
 		}
 		buffer.WriteRune('"')
 
-	case map[string]Animation:
+	case map[PropertyName]AnimationProperty:
 		switch count := len(value); count {
 		case 0:
 			buffer.WriteString("[]")
@@ -799,11 +787,13 @@ func writePropertyValue(buffer *strings.Builder, tag string, value any, indent s
 			}
 
 		default:
-			tags := make([]string, 0, len(value))
+			tags := make([]PropertyName, 0, len(value))
 			for tag := range value {
 				tags = append(tags, tag)
 			}
-			sort.Strings(tags)
+			sort.Slice(tags, func(i, j int) bool {
+				return tags[i] < tags[j]
+			})
 			buffer.WriteString("[\n")
 			indent2 := indent + "\t"
 			for _, tag := range tags {
@@ -819,12 +809,12 @@ func writePropertyValue(buffer *strings.Builder, tag string, value any, indent s
 	}
 }
 
-func writeViewStyle(name string, view ViewStyle, buffer *strings.Builder, indent string, excludeTags []string) {
+func writeViewStyle(name string, view Properties, buffer *strings.Builder, indent string, excludeTags []PropertyName) {
 	buffer.WriteString(name)
 	buffer.WriteString(" {\n")
 	indent += "\t"
 
-	writeProperty := func(tag string, value any) {
+	writeProperty := func(tag PropertyName, value any) {
 		for _, exclude := range excludeTags {
 			if exclude == tag {
 				return
@@ -833,7 +823,7 @@ func writeViewStyle(name string, view ViewStyle, buffer *strings.Builder, indent
 
 		if supportedPropertyValue(value) {
 			buffer.WriteString(indent)
-			buffer.WriteString(tag)
+			buffer.WriteString(string(tag))
 			buffer.WriteString(" = ")
 			writePropertyValue(buffer, tag, value, indent)
 			buffer.WriteString(",\n")
@@ -841,7 +831,7 @@ func writeViewStyle(name string, view ViewStyle, buffer *strings.Builder, indent
 	}
 
 	tags := view.AllTags()
-	removeTag := func(tag string) {
+	removeTag := func(tag PropertyName) {
 		for i, t := range tags {
 			if t == tag {
 				if i == 0 {
@@ -856,10 +846,11 @@ func writeViewStyle(name string, view ViewStyle, buffer *strings.Builder, indent
 		}
 	}
 
-	tagOrder := []string{
+	tagOrder := []PropertyName{
 		ID, Row, Column, Top, Right, Bottom, Left, Semantics, Cursor, Visibility,
 		Opacity, ZIndex, Width, Height, MinWidth, MinHeight, MaxWidth, MaxHeight,
-		Margin, Padding, BackgroundClip, BackgroundColor, Background, Border, Radius, Outline, Shadow,
+		Margin, Padding, BackgroundColor, Background, BackgroundClip, BackgroundOrigin,
+		Mask, MaskClip, MaskOrigin, Border, Radius, Outline, Shadow,
 		Orientation, ListWrap, VerticalAlign, HorizontalAlign, CellWidth, CellHeight,
 		CellVerticalAlign, CellHorizontalAlign, ListRowGap, ListColumnGap, GridRowGap, GridColumnGap,
 		ColumnCount, ColumnWidth, ColumnSeparator, ColumnGap, AvoidBreak,
@@ -877,10 +868,10 @@ func writeViewStyle(name string, view ViewStyle, buffer *strings.Builder, indent
 		}
 	}
 
-	finalTags := []string{
-		Perspective, PerspectiveOriginX, PerspectiveOriginY, BackfaceVisible, OriginX, OriginY, OriginZ,
-		TranslateX, TranslateY, TranslateZ, ScaleX, ScaleY, ScaleZ, Rotate, RotateX, RotateY, RotateZ,
-		SkewX, SkewY, Clip, Filter, BackdropFilter, Summary, Content, Transition}
+	finalTags := []PropertyName{
+		PerspectiveOriginX, PerspectiveOriginY, BackfaceVisible,
+		TransformOriginX, TransformOriginY, TransformOriginZ,
+		Transform, Clip, Filter, BackdropFilter, Summary, Content, Transition}
 	for _, tag := range finalTags {
 		removeTag(tag)
 	}
@@ -902,14 +893,6 @@ func writeViewStyle(name string, view ViewStyle, buffer *strings.Builder, indent
 	buffer.WriteString("}")
 }
 
-func getViewString(view View, excludeTags []string) string {
-	buffer := allocStringBuilder()
-	defer freeStringBuilder(buffer)
-	writeViewStyle(view.Tag(), view, buffer, "", excludeTags)
-	return buffer.String()
-
-}
-
 func runStringWriter(writer stringWriter) string {
 	buffer := allocStringBuilder()
 	defer freeStringBuilder(buffer)