blur image on ios 5 . ios6

最新推荐文章于 2025-07-01 22:53:21 发布

王晓鹏

最新推荐文章于 2025-07-01 22:53:21 发布

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本文介绍在iOS应用中实现模糊效果的两种方法：使用CoreImage框架中的CIGaussianBlur滤镜和利用Accelerate.Framework中的vImageAPI。这两种方法均可应用于图片处理，为用户提供更丰富的视觉体验。

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App设计时往往会用到一些模糊效果。iOS目前已提供一些模糊API可以让我们方便是使用。一种是使用Core Image，另一种是使用Accelerate.Framework中的vImage API。

使用Core Image进行模糊

Core Image很早在Mac系统中得到应用，后来这个Framework也开始应用到iOS，不过直到iOS6.0才开始支持模糊。这个API调用起来很方便简洁。

-
 (UIImage *)blurryImage:(UIImage *)image 

           withBlurLevel:(CGFloat)blur
 {

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

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

                         keysAndValues:kCIInputImageKey,
 inputImage,

                                       @"inputRadius",
 @(blur), 

                                       nil];

    CIImage
 *outputImage = filter.outputImage;

    CGImageRef
 outImage = [self.context
 createCGImage:outputImage 

                                   fromRect:[outputImage
 extent]];

    return

[UIImage imageWithCGImage:outImage];

}

使用vImage API进行模糊

iOS5.0中新增了vImage API可以使用，它属于Accelerate.Framework，所以如果你要使用它要在工程中加入这个Framework。模糊算法使用的是vImageBoxConvolve_ARGB8888这个函数。

-
 (UIImage *)blurryImage:(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);

    CGColorSpaceRelease(colorSpace);

    CGImageRelease(imageRef);

    return

returnImage;

}