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 "" then a top position of the first argument (view) is returned func GetFilter(view View, subviewID string) ViewFilter { if subviewID != "" { view = ViewByID(view, subviewID) } if view != nil { if value := view.getRaw(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 "" then a top position of the first argument (view) is returned func GetBackdropFilter(view View, subviewID string) ViewFilter { if subviewID != "" { view = ViewByID(view, subviewID) } if view != nil { if value := view.getRaw(BackdropFilter); value != nil { if filter, ok := value.(ViewFilter); ok { return filter } } } return nil }