1
发现这个小代码片段似乎做我想做的事情，但即时通过xcode说self.CGimage不是我的视图控制器的属性大吼。 （这是有道理的，因为这是一个UIimage属性）。我需要对此代码进行哪些更改才能使其功能化？谢谢！石英二维图像阿尔法掩模
- (UIImage*) maskImage:(UIImage *)image withMask:(UIImage *)maskImage {
CGContextRef mainViewContentContext;
CGColorSpaceRef colorSpace;
UIImage* tempImage;
colorSpace = CGColorSpaceCreateDeviceRGB();
// create a bitmap graphics context the size of the image
mainViewContentContext = CGBitmapContextCreate (NULL, image.size.width, image.size.height, 8, 0, colorSpace, kCGImageAlphaPremultipliedLast);
// free the rgb colorspace
CGColorSpaceRelease(colorSpace);
CGImageRef maskingImage = [maskImage CGImage];
CGContextClipToMask(mainViewContentContext, CGRectMake(0, 0, maskImage.size.width, maskImage.size.height), maskingImage);
CGContextDrawImage(mainViewContentContext, CGRectMake(0, 0, image.size.width, image.size.height), self.CGImage);
// Create CGImageRef of the main view bitmap content, and then
// release that bitmap context
CGImageRef mainViewContentBitmapContext = CGBitmapContextCreateImage(mainViewContentContext);
// convert the finished resized image to a UIImage
UIImage *theImage = [UIImage imageWithCGImage:mainViewContentBitmapContext];
// image is retained by the property setting above, so we can
// release the original
CGContextRelease(mainViewContentContext);
CGImageRelease(mainViewContentBitmapContext);
maskingImage = nil;
CGImageRelease(maskingImage);
// return the image
return theImage;
}