加入 CoreImage.framework CoreGraphic.framework 等库
在使用时引入：#import
<Accelerate/Accelerate.h> ，支持iOS 5.0 及以上。
-(void)show
{
UIImage* img = [self
getBlurImage:[UIImage
imageNamed:@"Default-568h.png"]];
[_bgImageView
setImage:img];
}
-(UIImage*)getBlurImage:(UIImage*)image
{
return [self
gaussBlur:0.2
andImage:image];
}
- (UIImage*)gaussBlur:(CGFloat)blurLevel andImage:(UIImage*)originImage
{
blurLevel = MIN(1.0,
MAX(0.0, blurLevel));
//int boxSize = (int)(blurLevel * 0.1 * MIN(self.size.width, self.size.height));
int boxSize =
50;//模糊度。
boxSize = boxSize - (boxSize % 2) +
1;
NSData *imageData =
UIImageJPEGRepresentation(originImage, 1);
UIImage *tmpImage = [UIImage
imageWithData:imageData];
CGImageRef img = tmpImage.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));
outBuffer.data = pixelBuffer;
outBuffer.width =
CGImageGetWidth(img);
outBuffer.height =
CGImageGetHeight(img);
outBuffer.rowBytes =
CGImageGetBytesPerRow(img);
NSInteger windowR = boxSize/2;
CGFloat sig2 = windowR /
3.0;
if(windowR>0){ sig2 = -1/(2*sig2*sig2); }
int16_t *kernel = (int16_t*)malloc(boxSize*sizeof(int16_t));
int32_t sum =
0;
for(NSInteger i=0; i<boxSize; ++i){
kernel[i] = 255*exp(sig2*(i-windowR)*(i-windowR));
sum += kernel[i];
}
free(kernel);
// convolution
error = vImageConvolve_ARGB8888(&inBuffer, &outBuffer,
NULL, 0,
0, kernel, boxSize, 1, sum,
NULL, kvImageEdgeExtend);
error = vImageConvolve_ARGB8888(&outBuffer, &inBuffer,
NULL, 0,
0, kernel, 1, boxSize, sum,
NULL, kvImageEdgeExtend);
outBuffer = inBuffer;
if (error) {
//NSLog(@"error from convolution %ld", error);
}
CGColorSpaceRef colorSpace =
CGColorSpaceCreateDeviceRGB();
CGContextRef ctx =
CGBitmapContextCreate(outBuffer.data,
outBuffer.width,
outBuffer.height,
8,
outBuffer.rowBytes,
colorSpace,
kCGBitmapAlphaInfoMask &
kCGImageAlphaNoneSkipLast);
CGImageRef imageRef =
CGBitmapContextCreateImage(ctx);
UIImage *returnImage = [UIImage
imageWithCGImage:imageRef];
//clean up
CGContextRelease(ctx);
CGColorSpaceRelease(colorSpace);
free(pixelBuffer);
CFRelease(inBitmapData);
CGImageRelease(imageRef);
return returnImage;
}