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Playback and Redraw Model

AnimationControl

AnimationControl is intentionally minimal:

• it starts requesting animation frames when attached to the visual tree,
• it stops when detached,
• and it calls OnAnimationFrame(TimeSpan now, TimeSpan last) before invalidating the control.

There is no explicit Start() or Pause() API in this package. If you need those semantics, move up to CompositionAnimatedControl.

CompositionAnimatedControl

CompositionAnimatedControl adds a higher-level playback model on top of a composition custom visual:

• Start(), Stop(), Pause(), Resume()
• Seek(TimeSpan position)
• RepeatCount
• PlaybackRate
• Position
• Redraw()

It also raises:

• Update(TimeSpan delta)
• Started
• Stopped
• Disposed

Time normalization

Custom subclasses can override OnNormalizeElapsed(TimeSpan elapsed) to map absolute elapsed time into:

• an effective elapsed value to render,
• plus a HasLooped flag.

That is how Lottie turns an ever-increasing clock into loop-aware playback for the current animation duration.

Static redraw scenarios

Not every Skia-backed control in this repository is continuously animated. CompositionAnimatedControl supports static redraw mode:

• do not call Start(),
• update your state from normal application events,
• call Redraw() when the visual needs another render pass.

The StaticRedrawControl sample in samples/CompositionAnimatedControlDemo demonstrates this pattern.