iOS7 毛玻璃效果

#import 

@interfaceUIImage(ImageEffects)

-(UIImage*)applyLightEffect;
-(UIImage*)applyExtraLightEffect;
-(UIImage*)applyDarkEffect;
-(UIImage*)applyTintEffectWithColor:(UIColor*)tintColor;

-(UIImage*)applyBlurWithRadius:(CGFloat)blurRadius tintColor:(UIColor*)tintColor saturationDeltaFactor:(CGFloat)saturationDeltaFactor maskImage:(UIImage*)maskImage;

@end

#import "UIImage+ImageEffects.h"

#import 
#import 


@implementationUIImage(ImageEffects)


-(UIImage*)applyLightEffect
{
UIColor*tintColor =[UIColor colorWithWhite:1.0 alpha:0.3];
return[self applyBlurWithRadius:30 tintColor:tintColor saturationDeltaFactor:1.8 maskImage:nil];
}


-(UIImage*)applyExtraLightEffect
{
UIColor*tintColor =[UIColor colorWithWhite:0.97 alpha:0.82];
return[self applyBlurWithRadius:20 tintColor:tintColor saturationDeltaFactor:1.8 maskImage:nil];
}


-(UIImage*)applyDarkEffect
{
UIColor*tintColor =[UIColor colorWithWhite:0.11 alpha:0.73];
return[self applyBlurWithRadius:20 tintColor:tintColor saturationDeltaFactor:1.8 maskImage:nil];
}


-(UIImage*)applyTintEffectWithColor:(UIColor*)tintColor
{
constCGFloatEffectColorAlpha=0.6;
UIColor*effectColor = tintColor;
int componentCount =CGColorGetNumberOfComponents(tintColor.CGColor);
if(componentCount ==2){
CGFloat b;
if([tintColor getWhite:&b alpha:NULL]){
effectColor =[UIColor colorWithWhite:b alpha:EffectColorAlpha];
}
}
else{
CGFloat r, g, b;
if([tintColor getRed:&r green:&g blue:&b alpha:NULL]){
effectColor =[UIColor colorWithRed:r green:g blue:b alpha:EffectColorAlpha];
}
}
return[self applyBlurWithRadius:10 tintColor:effectColor saturationDeltaFactor:-1.0 maskImage:nil];
}


-(UIImage*)applyBlurWithRadius:(CGFloat)blurRadius tintColor:(UIColor*)tintColor saturationDeltaFactor:(CGFloat)saturationDeltaFactor maskImage:(UIImage*)maskImage
{
// Check pre-conditions.
if(self.size.width <1||self.size.height <1){
NSLog(@"*** error: invalid size: (%.2f x %.2f). Both dimensions must be >= 1: %@",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:
// http://www.w3.org/TR/SVG/filters.html#feGaussianBlurElement
// 
// 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

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];