［IOS 开发代码］UIImage+Blur 网络图片模糊用法

    float quality = .00001f;
    float blurred = .5f;

    NSURL *url = [NSURL URLWithString:@"http://pic21.nipic.com/20120614/10230657_130343324168_2.jpg"];
    NSData *data = [[NSData alloc]initWithContentsOfURL:url];
    UIImage *img = [[UIImage alloc]initWithData:data];
    
    NSData *imageData = UIImageJPEGRepresentation(img, quality);
    userIcon.image = [[UIImage imageWithData:imageData] blurredImage:blurred];

//
//  UIImage+Blur.h



#import <UIKit/UIKit.h>
#import <Accelerate/Accelerate.h>
#import <QuartzCore/QuartzCore.h>

@interface UIImage (Blur)

// 0.0 to 1.0
- (UIImage*)blurredImage:(CGFloat)blurAmount;

@end

//
//  UIImage+Blur.m

#import "UIImage+Blur.h"

@implementation UIImage (Blur)

- (UIImage*)blurredImage:(CGFloat)blurAmount
{
    if (blurAmount < 0.0 || blurAmount > 1.0) {
        blurAmount = 0.5;
    }
    
    int boxSize = (int)(blurAmount * 40);
    boxSize = boxSize - (boxSize % 2) + 1;
    
    CGImageRef img = self.CGImage;

    vImage_Buffer inBuffer, outBuffer;
    vImage_Error error;
    
    void *pixelBuffer;
    
    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);

    pixelBuffer = malloc(CGImageGetBytesPerRow(img) * CGImageGetHeight(img));
    
    outBuffer.data = pixelBuffer;
    outBuffer.width = CGImageGetWidth(img);
    outBuffer.height = CGImageGetHeight(img);
    outBuffer.rowBytes = CGImageGetBytesPerRow(img);
    
    error = vImageBoxConvolve_ARGB8888(&inBuffer, &outBuffer, NULL, 0, 0, boxSize, boxSize, NULL, kvImageEdgeExtend);
    
    if (!error) {
        error = vImageBoxConvolve_ARGB8888(&outBuffer, &inBuffer, NULL, 0, 0, boxSize, boxSize, NULL, kvImageEdgeExtend);
    }
    
    if (error) {
#ifdef DEBUG
        NSLog(@"%s error: %zd", __PRETTY_FUNCTION__, error);
#endif
        
        return self;
    }
    
    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
    
    CGContextRef ctx = CGBitmapContextCreate(outBuffer.data,
                                             outBuffer.width,
                                             outBuffer.height,
                                             8,
                                             outBuffer.rowBytes,
                                             colorSpace,
                                             (CGBitmapInfo)kCGImageAlphaNoneSkipLast);
    
    CGImageRef imageRef = CGBitmapContextCreateImage (ctx);
    
    UIImage *returnImage = [UIImage imageWithCGImage:imageRef];
    
    CGContextRelease(ctx);
    CGColorSpaceRelease(colorSpace);
    
    free(pixelBuffer);
    CFRelease(inBitmapData);
    
    CGImageRelease(imageRef);
    
    return returnImage;
}

@end