iphone - How to get the alpha of an UIImage

Question

I have a UIImage. I need to find out its alpha value. Can someone explain it to me in detail, providing links to any references and also source code of how to go about this. Please don't provide answers for finding out the alpha of the UIImageView because I do NOT need that. Thanks in advance

Answer 1

您必须获得CGImageRef。一旦你有了它，你可以使用CGImageGetAlphaInfo方法返回图像的 alpha 通道信息。