Core Animation

渲染，合成和动画化视觉元素。

概述

Core Animation可提供高帧率和流畅的动画，而不会给CPU造成负担，也不会降低App的运行速度。绘制动画的每一帧所需的大部分工作都已经帮你完成。你可以配置动画参数（例如起点和终点），然后由Core Animation完成其余的工作，将大部分工作移交给专用图形硬件，以加快渲染速度。有关更多详细信息，请参见Core Animation编程指南。

主题

图层基础

• class CALayer

  一个对象，该对象管理基于图像的内容，并允许你对该内容执行动画。

protocol CALayerDelegate Methods your app can implement to respond to layer-related events.

class CAConstraint A representation of a single layout constraint between two layers.

protocol CALayoutManager Methods that allow an object to manage the layout of a layer and its sublayers.

class CAConstraintLayoutManager An object that provides a constraint-based layout manager.

protocol CAAction An interface that allows objects to respond to actions triggered by a CALayer change.