| 摘要 |
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, text, media, or other types of objects for an application's user interface. The application commits state changes to the layers of the layer tree. The application does not need to include explicit code for animating the changes to the layers. Instead, 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. Portions of the render tree changing relative to prior versions can be tracked to improve resource management. |
