问掩码UIImage iOS 8
EN

Stack Overflow用户

提问于 2014-10-13 02:24:30

回答 1查看 589关注 0票数 3

我使用下面的代码在iOS 7中屏蔽to图像，效果很好。但现在，在iOS 8中，它什么也做不了，不是返回原始图像+蒙版，而是返回一张黑色图像。

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

CGImageRef imgRef = [image CGImage];
CGImageRef maskRef = [maskImage CGImage];
CGImageRef actualMask = CGImageMaskCreate(CGImageGetWidth(maskRef),
                                          CGImageGetHeight(maskRef),
                                          CGImageGetBitsPerComponent(maskRef),
                                          CGImageGetBitsPerPixel(maskRef),
                                          CGImageGetBytesPerRow(maskRef),
                                          CGImageGetDataProvider(maskRef), NULL, false);
CGImageRef masked = CGImageCreateWithMask(imgRef, actualMask);
return [UIImage imageWithCGImage:masked];

}

这是我的应用程序的工作原理：-原始图像将被模糊-然后应用一个蒙版(圆形，正方形，任何形状。返回模糊的图像，遮罩应该裁剪模糊的图像，并在没有模糊的情况下看到原始图像的后面。它可以在iOS 7上工作，但在iOS 8中，关于掩码的代码(上面)不能工作。有什么想法吗？

ios

objective-c

xcode

回答 1

Stack Overflow用户

发布于 2014-12-01 10:56:28

使用此方法在iOS 8.0中遮罩图像。我已经在我的运行代码中使用了这个方法，并且工作得很好。

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

    CGImageRef imgRef  = [image CGImage];
    CGImageRef maskRef = [maskImage CGImage];


    int maskWidth      = CGImageGetWidth(maskRef);
    int maskHeight     = CGImageGetHeight(maskRef);
    //  round bytesPerRow to the nearest 16 bytes, for performance's sake
    int bytesPerRow    = (maskWidth + 15) & 0xfffffff0;
    int bufferSize     = bytesPerRow * maskHeight;

    //  allocate memory for the bits
    CFMutableDataRef dataBuffer = CFDataCreateMutable(kCFAllocatorDefault, 0);
    CFDataSetLength(dataBuffer, bufferSize);

    //  the data will be 8 bits per pixel, no alpha
    CGColorSpaceRef colourSpace = CGColorSpaceCreateDeviceGray();
    CGContextRef ctx            = CGBitmapContextCreate(CFDataGetMutableBytePtr(dataBuffer),
                                                        maskWidth, maskHeight,
                                                        8, bytesPerRow, colourSpace, kCGImageAlphaNone);
    //  drawing into this context will draw into the dataBuffer.
    CGContextDrawImage(ctx, CGRectMake(0, 0, maskWidth, maskHeight), maskRef);
    CGContextRelease(ctx);

    //  now make a mask from the data.
    CGDataProviderRef dataProvider  = CGDataProviderCreateWithCFData(dataBuffer);
    CGImageRef mask                 = CGImageMaskCreate(maskWidth, maskHeight, 8, 8, bytesPerRow,
                                                        dataProvider, NULL, FALSE);

    CGDataProviderRelease(dataProvider);
    CGColorSpaceRelease(colourSpace);
    CFRelease(dataBuffer);

    CGImageRef masked = CGImageCreateWithMask(imgRef, mask);
    return [UIImage imageWithCGImage:masked];

}