iOS圖片模糊效果

加入 CoreImage.framework CoreGraphic.framework 等庫

在使用時引入：#import ，支援iOS 5.0 及以上。

-(void)show

{

UIImage* img = [selfgetBlurImage:[UIImageimageNamed:@"Default-568h.png"]];

[_bgImageView setImage:img];

}

-(UIImage*)getBlurImage:(UIImage*)image

{

return [selfgaussBlur:0.2andImage: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 = [UIImageimageWithData: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

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 = [UIImageimageWithCGImage:imageRef];

//clean up

CGContextRelease(ctx);

CGColorSpaceRelease(colorSpace);

free(pixelBuffer);

CFRelease(inBitmapData);

CGImageRelease(imageRef);

return returnImage;

}