Apple Inc.
Frameworks for graphics animation and compositing operations

Abstract:

A graphics animation and compositing operations framework has a layer tree for interfacing with the application and a render tree for interfacing with a render engine. Layers in the layer tree can be content, windows, views, video, images, etc., for an application's user interface. The application commits state changes of the layers of the layer tree. The application does not need to include explicit code for animating the changes to the layers. Instead, after a synchronization threshold has been met, an animation is determined for animating the change in state by the framework which can define a set of predetermined animations based on motion, visibility and transition. The determined animation is explicitly applied to the affected layers in the render tree. A render engine renders from the render tree into a frame buffer, synchronized with the display. Portions of the render tree changing relative to prior versions can be tracked.