cocoa - 核心动画中的图层是什么

Question

在核心动画或应用程序工具包中当我们说图层支持 View 或简单地在 View 中添加图层时，实际上我们所说的图层是什么意思。

Answer 1

A simple Google search :

The CALayer is the canvas upon which everything in Core Animation is painted. When you define movement, color changes, image effects, and so on, those are applied to CALayer objects. From a code perspective, CALayers are a lightweight representation similar to an NSView. In fact, NSView objects can be manipulated via their CALayer. This is referred to as being layer-backed.