Variable onFrame

onFrame: (widget: Widget, callback: () => boolean) => CancelHandle

Type Declaration

- (widget: Widget, callback: () => boolean): CancelHandle
- Calls a callback on every frame tick, synchronised to the widget's GDK frame clock.
  
  The callback should return true to continue receiving frame updates, or false to stop. The animation is automatically cancelled when the widget is destroyed.
  Parameters
  - widget: Widget
    The widget whose frame clock should drive the animation
  - callback: () => boolean
    Called on each frame. Return false to stop.
  Returns CancelHandle
  A CancelHandle to cancel the animation externally
  Example
```
const handle = onFrame(myWidget, () => {
    opacity -= 0.02;
    myWidget.opacity = opacity;
    return opacity > 0;
});
```