图片的模糊处理blur

我简单说一下我写的这个例子大概有4种实现方式:

• 1.Core Image （里面使用了两种方法,但是两种方法都不是很好，好用内存相当大，有肯能存在内存泄露，及其不推荐）
• 2.GPUImage （第三方库已经加入到工程中，消耗内存也不小）
• 3.系统的方法 要使用vImageBoxConvolve_ARGB8888
• 4.rt_tintedImageWithColor（一个第三方库，具体地址忘记了） 主要利用CGContextSetFillColorWithColor和系统方法结合
• 5.还有就是模糊图片 加上半透明view 开销最小因为没有用代码实现模糊

主要推荐3\4\5 可以自己看一下内存占用率。

下面是效果图：

BlurImage.gif

下面是主要代码：

+ (UIImage *)blurryImage:(UIImage *)image withBlurLevel:(CGFloat)blur {

if 0

 //图片没有铺满 真心不知道怎么回事

 if (image == nil) {

 return nil;

 }

 CIImage *inputImage = [CIImage imageWithCGImage:image.CGImage];

 CGAffineTransform transform = CGAffineTransformIdentity;

 CIFilter *clampFilter = [CIFilter filterWithName:@"CIAffineClamp"];

 [clampFilter setValue:inputImage forKey:@"inputImage"];

 [clampFilter setValue:[NSValue valueWithBytes:&transform objCType:@encode(CGAffineTransform)] forKey:@"inputTransform"];

 CIFilter *gaussianBlurFilter = [CIFilter filterWithName: @"CIGaussianBlur"];

 [gaussianBlurFilter setValue:clampFilter.outputImage forKey: @"inputImage"];
 
[gaussianBlurFilter setValue:[NSNumber numberWithFloat:blur] forKey:@"inputRadius"];

 // CIFilter *filter = [CIFilter filterWithName:@"CIGaussianBlur"

 // keysAndValues:kCIInputImageKey, inputImage, nil];

// [filter setValue:[NSNumber numberWithFloat:blur] forKey:@"inputRadius"];

 CIImage *outputImage = gaussianBlurFilter.outputImage;

 CGRect rect = [outputImage extent];

 rect.origin.x += (rect.size.width - image.size.width ) / 2;

 rect.origin.y += (rect.size.height - image.size.height) / 2;

 rect.size = image.size;
 
CIImage* croppedImage = [outputImage imageByCroppingToRect:rect];

 UIImage * blurryImage = [UIImage imageWithCIImage:croppedImage];

 //该方法有内存泄露的问题

 // CIContext *context = [CIContext contextWithOptions:nil]; // save it to self.context

 // CGImageRef outImage = [context createCGImage:outputImage fromRect:rect];

 // UIImage * blurryImage = [UIImage imageWithCGImage:outImage];

 // CGImageRelease(outImage);

 return blurryImage;

#else

//而且不建议每次都建立context

CIImage *inputImage = [CIImage imageWithCGImage:image.CGImage];

CIFilter *filter = [CIFilter filterWithName:@"CIGaussianBlur"

keysAndValues:kCIInputImageKey, inputImage,
@"inputRadius", @(blur), nil];

CIImage *outputImage = filter.outputImage;

CIContext *context = [CIContext contextWithOptions:nil];

CGImageRef outImage = [context createCGImage:outputImage fromRect:[outputImage extent]];

UIImage *returnImage = [UIImage imageWithCGImage:outImage];

CGImageRelease(outImage);

return returnImage;
#endif
}

+ (UIImage *)blurrymage:(UIImage *)image withBlurLevel:(CGFloat)blur {

if (blur < 0.f || blur > 1.f) {

blur = 0.5f;

}

int boxSize = (int)(blur * 100);

boxSize = boxSize - (boxSize % 2) + 1;

CGImageRef img = image.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));


if(pixelBuffer == NULL)
    NSLog(@"No pixelbuffer");

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) {
NSLog(@"error from convolution %ld", error);
}

CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();

CGContextRef ctx = CGBitmapContextCreate(
outBuffer.data,
outBuffer.width,
outBuffer.height,
8,
outBuffer.rowBytes,
colorSpace,
kCGImageAlphaNoneSkipLast);
CGImageRef imageRef = CGBitmapContextCreateImage (ctx);
UIImage *returnImage = [UIImage imageWithCGImage:imageRef];
//clean up
CGContextRelease(ctx);
CGColorSpaceRelease(colorSpace);
free(pixelBuffer);
CFRelease(inBitmapData);
CGImageRelease(imageRef);
return returnImage;
}

-(UIImage*)rt_tintedImageWithColor:(UIColor*)color rect:(CGRect)rect level:(CGFloat)level {

CGRect imageRect = CGRectMake(0.0f, 0.0f, self.size.width, self.size.height);

UIGraphicsBeginImageContextWithOptions(imageRect.size, NO, self.scale);

CGContextRef ctx = UIGraphicsGetCurrentContext();

[self drawInRect:imageRect];

CGContextSetFillColorWithColor(ctx, [color CGColor]);

CGContextSetAlpha(ctx, level);

CGContextSetBlendMode(ctx, kCGBlendModeSourceAtop);

CGContextFillRect(ctx, rect);

CGImageRef imageRef = CGBitmapContextCreateImage(ctx);

UIImage *darkImage = [UIImage imageWithCGImage:imageRef
scale:self.scale
orientation:self.imageOrientation];

CGImageRelease(imageRef);

UIGraphicsEndImageContext();

return darkImage;

}

其他的可以看一下这个demo:
https://github.com/WonderC/BlurImageMethodDemo