如何使用其他混合模式（例如屏幕或乘法）渲染CALayer？

我有一个 UIImageView ，并希望它以特定的混合模式显示。我知道iPhone有不同的混合模式，可能可以用很多CG代码来完成它……但是 UIImageView ？

I have a UIImageView and want it to be displayed with a specific blend mode. I know the iPhone has different blend modes, and it's probably possible to do it with a lot of CG code… but maybe there's a nice way with the CALayer of UIImageView?