Added Start, Stop, Pause, and Resume methods to Animation interface

CHANGELOG.md

@@ -1,6 +1,7 @@
 # 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
 
 # v0.16.0
 * Can use ListAdapter as "content" property value of ListLayout

animation.go

@@ -121,6 +121,10 @@ type animationData struct {
 	propertyList
 	keyFramesName string
 	usageCounter  int
+	view          View
+	listener      func(view View, animation Animation, event string)
+	oldListeners  map[string][]func(View, string)
+	oldAnimation  []Animation
 }
 
 // Animation interface is used to set animation parameters. Used properties:
@@ -128,6 +132,17 @@ type animationData struct {
 type Animation interface {
 	Properties
 	fmt.Stringer
+
+	// Start starts the animation for the view specified by the first argument.
+	// The second argument specifies the animation event listener (can be nil)
+	Start(view View, listener func(view View, animation Animation, event string)) bool
+	// Stop stops the animation
+	Stop()
+	// Pause pauses the animation
+	Pause()
+	// Resume resumes an animation that was stopped using the Pause method
+	Resume()
+
 	writeTransitionString(tag string, buffer *strings.Builder)
 	animationCSS(session Session) string
 	transitionCSS(buffer *strings.Builder, session Session)
@@ -163,19 +178,29 @@ func NewAnimation(params Params) Animation {
 	return animation
 }
 
-func (animation *animationData) hasAnimatedProperty() bool {
-	props := animation.getRaw(PropertyTag)
-	if props == nil {
+func (animation *animationData) animatedProperties() []AnimatedProperty {
+	value := animation.getRaw(PropertyTag)
+	if value == nil {
 		ErrorLog("There are no animated properties.")
-		return false
+		return nil
 	}
 
-	if _, ok := props.([]AnimatedProperty); !ok {
+	props, ok := value.([]AnimatedProperty)
+	if !ok {
 		ErrorLog("Invalid animated properties.")
-		return false
+		return nil
 	}
 
-	return true
+	if len(props) == 0 {
+		ErrorLog("There are no animated properties.")
+		return nil
+	}
+
+	return props
+}
+
+func (animation *animationData) hasAnimatedProperty() bool {
+	return animation.animatedProperties() != nil
 }
 
 func (animation *animationData) animationName() string {
@@ -394,19 +419,11 @@ func (animation *animationData) String() string {
 
 func (animation *animationData) animationCSS(session Session) string {
 	if animation.keyFramesName == "" {
-		props := animation.getRaw(PropertyTag)
-		if props == nil {
-			ErrorLog("There are no animated properties.")
+		if props := animation.animatedProperties(); props != nil {
+			animation.keyFramesName = session.registerAnimation(props)
+		} else {
 			return ""
 		}
-
-		animatedProps, ok := props.([]AnimatedProperty)
-		if !ok || len(animatedProps) == 0 {
-			ErrorLog("Invalid animated properties.")
-			return ""
-		}
-
-		animation.keyFramesName = session.registerAnimation(animatedProps)
 	}
 
 	buffer := allocStringBuilder()

animationRun.go

@@ -0,0 +1,109 @@
+package rui
+
+func (animation *animationData) Start(view View, listener func(view View, animation Animation, event string)) 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(AnimationTag); value != nil {
+		if oldAnimation, ok := value.([]Animation); ok && len(oldAnimation) > 0 {
+			animation.oldAnimation = oldAnimation
+		}
+	}
+
+	animation.oldListeners = map[string][]func(View, string){}
+
+	setListeners := func(event string, listener func(View, string)) {
+		var listeners []func(View, string) = nil
+		if value := view.Get(event); value != nil {
+			if oldListeners, ok := value.([]func(View, string)); 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(AnimationTag, animation)
+	return true
+}
+
+func (animation *animationData) finish() {
+	if animation.view != nil {
+		for _, event := range []string{AnimationStartEvent, AnimationEndEvent, AnimationCancelEvent, AnimationIterationEvent} {
+			if listeners, ok := animation.oldListeners[event]; ok {
+				animation.view.Set(event, listeners)
+			} else {
+				animation.view.Remove(event)
+			}
+		}
+
+		animation.view.Set(AnimationTag, animation.oldAnimation)
+
+		animation.oldListeners = map[string][]func(View, string){}
+		animation.oldAnimation = nil
+		animation.view = nil
+		animation.listener = nil
+	}
+}
+
+func (animation *animationData) Stop() {
+	animation.finish()
+}
+
+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, _ string) {
+	if animation.view != nil && animation.listener != nil {
+		animation.listener(animation.view, animation, AnimationStartEvent)
+	}
+}
+
+func (animation *animationData) onAnimationEnd(view View, _ string) {
+	if animation.view != nil {
+		if animation.listener != nil {
+			animation.listener(animation.view, animation, AnimationEndEvent)
+		}
+		animation.finish()
+	}
+}
+
+func (animation *animationData) onAnimationIteration(view View, _ string) {
+	if animation.view != nil && animation.listener != nil {
+		animation.listener(animation.view, animation, AnimationIterationEvent)
+	}
+}
+
+func (animation *animationData) onAnimationCancel(view View, _ string) {
+	if animation.view != nil && animation.listener != nil {
+		animation.listener(animation.view, animation, AnimationCancelEvent)
+	}
+}

canvas.go

@@ -299,10 +299,13 @@ 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
 }
 

session.go

@@ -144,7 +144,9 @@ type Session interface {
 	sendResponse()
 	addAnimationCSS(css string)
 	removeAnimation(keyframe string)
-	canvasStart(htmlID string)
+	htmlPropertyValue(htmlID, name string) string
+
+	canvasStart(htmlID string) bool
 	callCanvasFunc(funcName string, args ...any)
 	createCanvasVar(funcName string, args ...any) any
 	callCanvasVarFunc(v any, funcName string, args ...any)
@@ -152,7 +154,7 @@ type Session interface {
 	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)
@@ -427,20 +429,32 @@ 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")
+		}
 	}
 }
 
@@ -448,18 +462,23 @@ 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")
 	}
 }
 
@@ -467,6 +486,8 @@ func (session *sessionData) addAnimationCSS(css string) {
 	session.animationCSS += css
 	if session.bridge != nil {
 		session.bridge.appendAnimationCSS(css)
+	} else {
+		ErrorLog("No connection")
 	}
 }
 
@@ -503,14 +524,20 @@ func (session *sessionData) removeAnimation(keyframe string) {
 		session.animationCSS = css[:index] + css[end:]
 		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) {
@@ -587,6 +614,8 @@ func (session *sessionData) handleAnswer(command string, data DataObject) bool {
 
 	if session.bridge != nil {
 		session.bridge.sendResponse()
+	} else {
+		ErrorLog("No connection")
 	}
 	return true
 }