iOS圖片模糊效果 – iPhone手機開發技術文章 iPhone軟體開發教學課程

加入 CoreImage.framework CoreGraphic.framework 等庫

在使用時引入:#import
,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;

}

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