buildScene method
- SceneBuilder builder
Consider this layer as the root and build a scene (a tree of layers) in the engine.
Implementation
// The reason this method is in the `ContainerLayer` class rather than
// `PipelineOwner` or other singleton level is because this method can be used
// both to render the whole layer tree (e.g. a normal application frame) and
// to render a subtree (e.g. `OffsetLayer.toImage`).
ui.Scene buildScene(ui.SceneBuilder builder) {
updateSubtreeNeedsAddToScene();
addToScene(builder);
if (subtreeHasCompositionCallbacks) {
_fireCompositionCallbacks(includeChildren: true);
}
// Clearing the flag _after_ calling `addToScene`, not _before_. This is
// because `addToScene` calls children's `addToScene` methods, which may
// mark this layer as dirty.
_needsAddToScene = false;
final ui.Scene scene = builder.build();
return scene;
}