addToScene method

  1. @override
EngineLayer addToScene (SceneBuilder builder, [ Offset layerOffset = Offset.zero ])
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
ui.EngineLayer addToScene(ui.SceneBuilder builder, [Offset layerOffset = Offset.zero]) {
  bool enabled = true;
  assert(() {
    enabled = !debugDisableOpacityLayers;
    return true;
  }());
  if (enabled)
    builder.pushOpacity(alpha, offset: offset + layerOffset);
  addChildrenToScene(builder);
  if (enabled)
    builder.pop();
  return null; // this does not return an engine layer yet.
}