Added "outline-offset" property

README.md

@@ -745,7 +745,7 @@ If all the lines of the frame are the same, then the following properties can be
 |-----------|----------|----------|---------------------|
 | "style"   | Style    | int      | Border line style   |
 | "width"   | Width    | SizeUnit | Border line width   |
-| "color"   | Color    | Color    | Border line color   |
+| "color"   | ColorTag | Color    | Border line color   |
 
 Example
 
@@ -836,6 +836,48 @@ equivalent to
 		rui.ColorProperty: rui.Black,
 	}))
 
+### "outline" and "outline-offset" properties
+
+The "outline" property defines the border outside the View.
+A frame line is described by three attributes: line style, thickness, and color.
+
+The "outline" property is similar to the "border" property. The three main differences between an "outline" frame and a "border" frame are:
+
+1) the "border" frame is always located inside the boundaries of the View, and the "outline" frame can be located both inside the View and outside it;
+
+2) all sides of the "outline" frame are the same, while the sides of the "border" frame can have different color, style and thickness.
+
+3) "border" thickness is added to "padding" and "outline" thickness does not affect "padding".
+
+The value of the "border" property is stored as an OutlineProperty interface that implements the Properties interface (see above).
+OutlineProperty can contain the following properties:
+
+| Property  | Constant | Type     | Description         |
+|-----------|----------|----------|---------------------|
+| "style"   | Style    | int      | Border line style   |
+| "width"   | Width    | SizeUnit | Border line width   |
+| "color"   | ColorTag | Color    | Border line color   |
+
+Line style can take the following values:
+
+| Value | Constant   | Name     | Description         |
+|:-----:|------------|----------|---------------------|
+| 0     | NoneLine   | "none"   | No frame            |
+| 1     | SolidLine  | "solid"  | Solid line          |
+| 2     | DashedLine | "dashed" | Dashed line         |
+| 3     | DottedLine | "dotted" | Dotted line         |
+| 4     | DoubleLine | "double" | Double solid line   |
+
+All other style values are ignored.
+
+The NewOutline function is used to create the OutlineProperty interface.
+
+By default, the inner border of the "outline" border is the same as the border of the View (i.e. the border is drawn around the View).
+To change this behavior, use the "outline-offset" SizeUnit property (OutlineOffset constant).
+This property defines the distance between the inner border of the frame and the border of the View.
+A positive value moves the frame away from the View's boundaries, while a negative value forces the frame to be inside the View
+(in this case, the frame is drawn on top of the contents of the View).
+
 ### "radius" property
 
 The "radius" property sets the elliptical corner radius of the View. Radii are specified by the RadiusProperty

propertyNames.go

@@ -277,6 +277,10 @@ const (
 	// The "outline-width" SizeUnit property sets the width of an view's outline.
 	OutlineWidth = "outline-width"
 
+	// OutlineWidth is the constant for the "outline-offset" property tag.
+	// The "outline-offset" SizeUnit property sets the amount of space between an outline and the edge or border of an element..
+	OutlineOffset = "outline-offset"
+
 	// Shadow is the constant for the "shadow" property tag.
 	// The "shadow" property adds shadow effects around a view's frame. A shadow is described
 	// by X and Y offsets relative to the element, blur and spread radius, and color.

propertySet.go

@@ -136,6 +136,7 @@ var sizeProperties = map[string]string{
 	BorderTopWidth:     BorderTopWidth,
 	BorderBottomWidth:  BorderBottomWidth,
 	OutlineWidth:       OutlineWidth,
+	OutlineOffset:      OutlineOffset,
 	XOffset:            XOffset,
 	YOffset:            YOffset,
 	BlurRadius:         BlurRadius,

viewStyle.go

@@ -212,7 +212,7 @@ func (style *viewStyle) cssViewStyle(builder cssBuilder, session Session) {
 	for _, tag := range []string{
 		Width, Height, MinWidth, MinHeight, MaxWidth, MaxHeight, Left, Right, Top, Bottom,
 		TextSize, TextIndent, LetterSpacing, WordSpacing, LineHeight, TextLineThickness,
-		ListRowGap, ListColumnGap, GridRowGap, GridColumnGap, ColumnGap, ColumnWidth} {
+		ListRowGap, ListColumnGap, GridRowGap, GridColumnGap, ColumnGap, ColumnWidth, OutlineOffset} {
 
 		if size, ok := sizeProperty(style, tag, session); ok && size.Type != Auto {
 			cssTag, ok := sizeProperties[tag]

viewUtils.go

@@ -321,6 +321,12 @@ func GetOutline(view View, subviewID ...string) ViewOutline {
 	return ViewOutline{Style: NoneLine, Width: AutoSize(), Color: 0}
 }
 
+// GetOutlineOffset returns the subview outline offset.
+// If the second argument (subviewID) is not specified or it is "" then a offset of the first argument (view) is returned
+func GetOutlineOffset(view View, subviewID ...string) SizeUnit {
+	return sizeStyledProperty(view, subviewID, OutlineOffset, false)
+}
+
 // GetViewShadows returns shadows of the subview.
 // If the second argument (subviewID) is not specified or it is "" then shadows of the first argument (view) is returned.
 func GetViewShadows(view View, subviewID ...string) []ViewShadow {