iOS毛玻璃效果实现

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

#import <UIKit/UIKit.h>

@interface UIImage (ImageEffects)

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

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

@endUIImage+ImageEffects.m
#import "UIImage+ImageEffects.h"

#import <Accelerate/Accelerate.h>
#import <float.h>

@implementation UIImage (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
{
const CGFloat EffectColorAlpha = 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);
return nil;
}
if (!self.CGImage) {
NSLog (@"*** error: image must be backed by a CGImage: %@", self);
return nil;
}
if (maskImage && !maskImage.CGImage) {
NSLog (@"*** error: maskImage must be backed by a CGImage: %@", maskImage);
return nil;
}

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,
};
const int32_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_ARGB888
a616
8(&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];