遮罩图像时崩溃

Question

我正在尝试用“遮罩图像”遮罩图像。它在第一次运行得很好。但当我在应用程序中使用相同的蒙版图像再次尝试时，应用程序崩溃。当尝试使用另一个蒙版图像时，它可以正常工作。这一切为什么要发生？

控制台显示<Error>: CGImageMaskCreate: invalid mask bits/component: 4294967295.

- (UIImage*) maskImage:(UIImage *)image withMask:(UIImage *)maskImage {

    CGImageRef maskRef = maskImage.CGImage;

    CGImageRef mask = CGImageMaskCreate(CGImageGetWidth(maskRef),
    CGImageGetHeight(maskRef),
    CGImageGetBitsPerComponent(maskRef),
    CGImageGetBitsPerPixel(maskRef),
    CGImageGetBytesPerRow(maskRef),
    CGImageGetDataProvider(maskRef), NULL, false);

    CGImageRef masked = CGImageCreateWithMask([image CGImage], mask);
    UIImage *img2=[UIImage imageWithCGImage:masked];

    CGImageRelease(maskRef);
    CGImageRelease(mask);
    CGImageRelease(masked);

    return img2;
}

fun1()
{
view.image=[self maskImage:image1 withMask:[UIImage imageNamed:@"image2.png"]];
}

fun2()
{
view.image=[self maskImage:image1 withMask:[UIImage imageNamed:@"image2.png"]]; view.image=[self maskImage:image1 withMask:[UIImage imageNamed:@"image3.png"]];
}

fun3()
{
view.image=[self maskImage:image1 withMask:[UIImage imageNamed:@"image2.png"]];
view.image=[self maskImage:image1 withMask:[UIImage imageNamed:@"image2.png"]];
}

在调用fun1和fun2时，应用程序工作正常。调用fun3时应用程序崩溃。

Answer 1

你为什么要发布maskRef？你不应该这样，因为你没有保留它。

Answer 2

以下是您正在尝试做的事情，没有内存泄漏或崩溃：

    - (UIImage*) maskImage:(UIImage *)image
              withMask:(UIImage *)maskImage
{
        CGImageRef imageRef = image.CGImage;
        CGImageRef maskRef = maskImage.CGImage;  
        CGImageRef mask = CGImageMaskCreate(CGImageGetWidth(maskRef),
                                      CGImageGetHeight(maskRef),
                                      CGImageGetBitsPerComponent(maskRef),
                                      CGImageGetBitsPerPixel(maskRef),
                                      CGImageGetBytesPerRow(maskRef),
                                      CGImageGetDataProvider(maskRef),
                                      NULL, // decode should be NULL
                                      FALSE // shouldInterpolate
                                      );

        CGImageRef masked = CGImageCreateWithMask(imageRef, mask);
        CGImageRelease(mask);
        UIImage *maskedImage = [UIImage imageWithCGImage:masked];
        CGImageRelease(masked);
        return maskedImage;
}