原图：
[img]http://files.jb51.net/file_images/article/201410/20141026163258444.jpg?2014926163329[/img]
效果图：
[img]http://files.jb51.net/file_images/article/201410/20141026163341610.jpg?2014926163357[/img]
实现：
首先需要导入Accelerate.framework。
然后把两个文件加入到自己的项目中即可。
UIImage+ImageEffects.h
%@",self.size.width,self.size.height,self);
returnnil;
}
if(!self.CGImage){
NSLog(@"*** error: image must be backed by a CGImage: %@",self);
returnnil;
}
if(maskImage &&!maskImage.CGImage){
NSLog(@"*** error: maskImage must be backed by a CGImage: %@", maskImage);
returnnil;
}
CGRect imageRect ={CGPointZero,self.size };
UIImage*effectImage =self;
BOOL hasBlur = blurRadius > __FLT_EPSILON__;
BOOL hasSaturationChange = fabs(saturationDeltaFactor -1.)> __FLT_EPSILON__;
if(hasBlur || hasSaturationChange){
UIGraphicsBeginImageContextWithOptions(self.size, NO,[[UIScreen mainScreen] scale]);
CGContextRef effectInContext =UIGraphicsGetCurrentContext();
CGContextScaleCTM(effectInContext,1.0,-1.0);
CGContextTranslateCTM(effectInContext,0,-self.size.height);
CGContextDrawImage(effectInContext, imageRect,self.CGImage);
vImage_Buffer effectInBuffer;
effectInBuffer.data =CGBitmapContextGetData(effectInContext);
effectInBuffer.width =CGBitmapContextGetWidth(effectInContext);
effectInBuffer.height =CGBitmapContextGetHeight(effectInContext);
effectInBuffer.rowBytes =CGBitmapContextGetBytesPerRow(effectInContext);
UIGraphicsBeginImageContextWithOptions(self.size, NO,[[UIScreen mainScreen] scale]);
CGContextRef effectOutContext =UIGraphicsGetCurrentContext();
vImage_Buffer effectOutBuffer;
effectOutBuffer.data =CGBitmapContextGetData(effectOutContext);
effectOutBuffer.width =CGBitmapContextGetWidth(effectOutContext);
effectOutBuffer.height =CGBitmapContextGetHeight(effectOutContext);
effectOutBuffer.rowBytes =CGBitmapContextGetBytesPerRow(effectOutContext);
if(hasBlur){
// A description of how to compute the box kernel width from the Gaussian
// radius (aka standard deviation) appears in the SVG spec:
// [url=http://www.w3.org/TR/SVG/filters.html#feGaussianBlurElement]http://www.w3.org/TR/SVG/filters.html#feGaussianBlurElement[/url]
//
// For larger values of 's' (s >= 2.0), an approximation can be used: Three
// successive box-blurs build a piece-wise quadratic convolution kernel, which
// approximates the Gaussian kernel to within roughly 3%.
//
// let d = floor(s * 3*sqrt(2*pi)/4 + 0.5)
//
// ... if d is odd, use three box-blurs of size 'd', centered on the output pixel.
//
CGFloat inputRadius = blurRadius *[[UIScreen mainScreen] scale];
NSUInteger radius = floor(inputRadius *3.* sqrt(2* M_PI)/4+0.5);
if(radius %2!=1){
radius +=1;// force radius to be odd so that the three box-blur methodology works.
}
vImageBoxConvolve_ARGB8888(&effectInBuffer,&effectOutBuffer, NULL,0,0, radius, radius,0, kvImageEdgeExtend);
vImageBoxConvolve_ARGB8888(&effectOutBuffer,&effectInBuffer, NULL,0,0, radius, radius,0, kvImageEdgeExtend);
vImageBoxConvolve_ARGB8888(&effectInBuffer,&effectOutBuffer, NULL,0,0, radius, radius,0, kvImageEdgeExtend);
}
BOOL effectImageBuffersAreSwapped = NO;
if(hasSaturationChange){
CGFloat s = saturationDeltaFactor;
CGFloat floatingPointSaturationMatrix[]={
0.0722+0.9278* s,0.0722-0.0722* s,0.0722-0.0722* s,0,
0.7152-0.7152* s,0.7152+0.2848* s,0.7152-0.7152* s,0,
0.2126-0.2126* s,0.2126-0.2126* s,0.2126+0.7873* s,0,
0,0,0,1,
};
constint32_t divisor =256;
NSUInteger matrixSize =sizeof(floatingPointSaturationMatrix)/sizeof(floatingPointSaturationMatrix[0]);
int16_t saturationMatrix[matrixSize];
for(NSUInteger i =0; i < matrixSize;++i){
saturationMatrix[i]=(int16_t)roundf(floatingPointSaturationMatrix[i]* divisor);
}
if(hasBlur){
vImageMatrixMultiply_ARGB8888(&effectOutBuffer,&effectInBuffer, saturationMatrix, divisor, NULL, NULL, kvImageNoFlags);
effectImageBuffersAreSwapped = YES;
}
else{
vImageMatrixMultiply_ARGB8888(&effectInBuffer,&effectOutBuffer, saturationMatrix, divisor, NULL, NULL, kvImageNoFlags);
}
}
if(!effectImageBuffersAreSwapped)
effectImage =UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
if(effectImageBuffersAreSwapped)
effectImage =UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
}
// Set up output context.
UIGraphicsBeginImageContextWithOptions(self.size, NO,[[UIScreen mainScreen] scale]);
CGContextRef outputContext =UIGraphicsGetCurrentContext();
CGContextScaleCTM(outputContext,1.0,-1.0);
CGContextTranslateCTM(outputContext,0,-self.size.height);
// Draw base image.
CGContextDrawImage(outputContext, imageRect,self.CGImage);
// Draw effect image.
if(hasBlur){
CGContextSaveGState(outputContext);
if(maskImage){
CGContextClipToMask(outputContext, imageRect, maskImage.CGImage);
}
CGContextDrawImage(outputContext, imageRect, effectImage.CGImage);
CGContextRestoreGState(outputContext);
}
// Add in color tint.
if(tintColor){
CGContextSaveGState(outputContext);
CGContextSetFillColorWithColor(outputContext, tintColor.CGColor);
CGContextFillRect(outputContext, imageRect);
CGContextRestoreGState(outputContext);
}
// Output image is ready.
UIImage*outputImage =UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return outputImage;
}
@end
调用：
UIImageView*me =[[UIImageView alloc] initWithFrame:CGRectMake(10,480,614,381)];
[me setImage:[[UIImage imageNamed:@"me.png"] applyBlurWithRadius:5 tintColor:[UIColor colorWithWhite:1 alpha:0.2] saturationDeltaFactor:1.8 maskImage:nil]];
[self.view addSubview:me];
ok！So easy！
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