使用CGImageMaskCreate/imageWithCGImage应用图像掩码时的内存泄漏

Question

这个代码泄露了，如果有人能告诉我为什么？

    UIGraphicsBeginImageContext(drawingImage.frame.size);

    [drawingImage.image drawInRect:CGRectMake(0, 0, drawingImage.frame.size.width, drawingImage.frame.size.height)];
    // Draw some vectorial data
    // ...
    // Apply an image mask 
    CGImageRef maskRef = mask.CGImage; 
    CGImageRef cgmask = CGImageMaskCreate(CGImageGetWidth(maskRef),
                                          CGImageGetHeight(maskRef),
                                          CGImageGetBitsPerComponent(maskRef),
                                          CGImageGetBitsPerPixel(maskRef),
                                          CGImageGetBytesPerRow(maskRef),
                                          CGImageGetDataProvider(maskRef), NULL, false);

    CGImageRef masked = CGImageCreateWithMask([UIGraphicsGetImageFromCurrentImageContext() CGImage], cgmask);
    CGImageRelease(cgmask);

    drawingImage.image = [UIImage imageWithCGImage:masked];

    UIGraphicsEndImageContext();

Answer 1

masked未释放，一旦您使用它创建了镜像，您需要释放它

drawingImage.image = [UIImage imageWithCGImage:masked];
CGImageRelease(masked)