addToScene method Null safety

  1. @override
void addToScene(
  1. SceneBuilder builder
)
override

Override this method to upload this layer to the engine.

Return the engine layer for retained rendering. When there's no corresponding engine layer, null is returned.

Implementation

@override
void addToScene(ui.SceneBuilder builder) {
  // Skia has a fast path for concatenating scale/translation only matrices.
  // Hence pushing a translation-only transform layer should be fast. For
  // retained rendering, we don't want to push the offset down to each leaf
  // node. Otherwise, changing an offset layer on the very high level could
  // cascade the change to too many leaves.
  engineLayer = builder.pushOffset(
    offset.dx,
    offset.dy,
    oldLayer: _engineLayer as ui.OffsetEngineLayer?,
  );
  addChildrenToScene(builder);
  builder.pop();
}