iOS图片模糊效果
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;
}