CAReplicatorLayer背后的魔力是什么？ [英] What's the magic behind CAReplicatorLayer?
问题描述
我对CAReplicatorLayer感兴趣的是：
What I find interesting with CAReplicatorLayer:
- 它能够非常有效地多次显示CALayer并具有不同的变换（如何？）
- 似乎它以某种方式重复使用复制层的后备存储，甚至为它应用了一些颜色（如何？）
我想了解源代码或了解CAReplicatorLayer背后的魔力。我想有一个类似于CAReplicatorLayer的CALayer类，但有更多的控制权。我想对每个复制的实例单独控制转换。
I would like to get hands on either the source code or get some knowledge of the magic behind CAReplicatorLayer. I would like to have a CALayer class similar to CAReplicatorLayer, but with more control. I would like to have control on the transform individually for each replicated instance.
所以要求完全不同方式：
是否有可能获得CALayer的后备商店并显示它但我想要多次我想要？
So asked in a totally different manner: is it possible to get the "backing store" for a CALayer and display it however I want as many times I want?
（通过支持 store我的意思是CALayer / UIView的渲染纹理。我不太了解CoreAnimation / QuartzCore引擎盖下发生的事情。
(by "backing store" I mean the rendered texture for the CALayer/UIView. I don't know much about what's happening under the hoods of CoreAnimation/QuartzCore).
为什么我不会选择像将CALayer渲染为UIImage：
Why I'm not looking at alternatives like e.g. rendering the CALayer to a UIImage:
- 表现
- 内容是动态的/经常变化的转换
- 以其他方式做到这一点真是令人敬畏！
推荐答案
像CAReplicatorLayer或CAGradientLayer这样的专用CALayers能够（通过私有API）使用快速填充或复制直接在GPU上执行绘图。从某种意义上说，它们是不同的，因为后备存储不在普通RAM中，而是直接在GPU上。
The special-purpose CALayers like CAReplicatorLayer or CAGradientLayer are able (via private APIs) do execute their drawing directly on the GPU using fast filling or copying. In a sense they are different such that the backing store is not in normal RAM, but directly on the GPU.
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