View模糊化操作

-(UIImage *)boxblurImageWithBlur:(CGFloat)blur {

    if (blur < 0.f || blur > 1.f) {

        blur = 0.5f;

    }

    int boxSize = (int)(blur * 50);

    boxSize = boxSize - (boxSize % 2) + 1;

    

    CGImageRef img = self.CGImage;

    

    vImage_Buffer inBuffer, outBuffer;

    

    vImage_Error error;

    

    void *pixelBuffer;

    

    

    //create vImage_Buffer with data from CGImageRef

    

    CGDataProviderRef inProvider = CGImageGetDataProvider(img);

    CFDataRef inBitmapData = CGDataProviderCopyData(inProvider);

    

    inBuffer.width = CGImageGetWidth(img);

    inBuffer.height = CGImageGetHeight(img);

    inBuffer.rowBytes = CGImageGetBytesPerRow(img);

    

    inBuffer.data = (void*)CFDataGetBytePtr(inBitmapData);

    

    //create vImage_Buffer for output

    

    pixelBuffer = malloc(CGImageGetBytesPerRow(img) * CGImageGetHeight(img));

    

    if(pixelBuffer == NULL)

        NSLog(@"No pixelbuffer");

    

    outBuffer.data = pixelBuffer;

    outBuffer.width = CGImageGetWidth(img);

    outBuffer.height = CGImageGetHeight(img);

    outBuffer.rowBytes = CGImageGetBytesPerRow(img);

    

    //perform convolution

    error = vImageBoxConvolve_ARGB8888(&inBuffer, &outBuffer, NULL, 0, 0, boxSize, boxSize, NULL,kvImageEdgeExtend);

    

    

    if (error) {

        NSLog(@"error from convolution %ld", error);

    }

    

    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();

    CGContextRef ctx = CGBitmapContextCreate(outBuffer.data,

                                             outBuffer.width,

                                             outBuffer.height,

                                             8,

                                             outBuffer.rowBytes,

                                             colorSpace,

                                             kCGImageAlphaNoneSkipLast);

    CGImageRef imageRef = CGBitmapContextCreateImage (ctx);

    UIImage *returnImage = [UIImage imageWithCGImage:imageRef];

    

    //clean up

    CGContextRelease(ctx);

    CGColorSpaceRelease(colorSpace);

    

    free(pixelBuffer);

    CFRelease(inBitmapData);

    

    CGColorSpaceRelease(colorSpace);

    CGImageRelease(imageRef);

    

    return returnImage;

}