Improved synchronization with a quit signal.

ui/context.go

@@ -14,7 +14,7 @@ var _ EventTarget = &context{}
 
 type context struct {
 	animate bool
-	quit    bool
+	quit    chan struct{}
 	r       Renderer
 	view    Control
 	ims     *Images
@@ -23,11 +23,22 @@ type context struct {
 
 func (c *context) Animate() { c.animate = true }
 
-func (c *context) HasQuit() bool { return c.quit }
+func (c *context) HasQuit() bool {
+	select {
+	case <-c.quit:
+		return true
+	default:
+		return false
+	}
+}
 
 func (c *context) Images() *Images { return c.ims }
 
-func (c *context) Quit() { c.quit = true }
+func (c *context) Quit() {
+	if !c.HasQuit() {
+		close(c.quit)
+	}
+}
 
 func (c *context) Renderer() Renderer { return c.r }
 

ui/ui.go

@@ -13,7 +13,7 @@ func Run(r Renderer, s *Style, view Control) error {
 
 // RunWait runs the application loop and conditionally waits on events before rendering.
 func RunWait(r Renderer, s *Style, view Control, wait bool) error {
-	ctx := &context{r: r, style: s, view: view, ims: NewImages(r)}
+	ctx := &context{quit: make(chan struct{}), r: r, style: s, view: view, ims: NewImages(r)}
 	root, ok := view.(RootControl)
 	if ok {
 		err := root.Init(ctx)
@@ -23,24 +23,30 @@ func RunWait(r Renderer, s *Style, view Control, wait bool) error {
 	}
 	anim := time.NewTicker(30 * time.Millisecond)
 	go func() {
-		for range anim.C {
-			if ctx.animate && !ctx.quit {
+		for {
+			select {
+			case <-anim.C:
+			case <-ctx.quit:
+				return
+			}
+			if ctx.animate {
 				r.Refresh()
 			}
 			ctx.animate = false
 		}
 	}()
+	defer anim.Stop()
+
 	ctx.Renderer().Refresh()
-	for !ctx.quit {
+	for !ctx.HasQuit() {
 		var size = r.Size()
 		var bounds = geom.RectF32(0, 0, size.X, size.Y)
 		view.Arrange(ctx, bounds, geom.ZeroPtF32, nil)
 		view.Render(ctx)
-		if ctx.quit {
+		if ctx.HasQuit() {
 			return nil
 		}
 		r.PushEvents(ctx, wait)
 	}
-	anim.Stop()
 	return nil
 }