ios 玻璃层效果

- (UIImage *)blurryImage:(UIImage *)image withBlurLevel:(CGFloat)blur {

if ((blur < 0.0f) || (blur > 1.0f)) {

blur = 0.5f;

}

int boxSize = (int)(blur * 100);

boxSize -= (boxSize % 2) + 1;

CGImageRef img = image.CGImage;

vImage_Buffer inBuffer, outBuffer;

vImage_Error error;

void *pixelBuffer;

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);

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

outBuffer.data = pixelBuffer;

outBuffer.width = CGImageGetWidth(img);

outBuffer.height = CGImageGetHeight(img);

outBuffer.rowBytes = CGImageGetBytesPerRow(img);

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,

CGImageGetBitmapInfo(image.CGImage));

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;

}