ios vimagebuffer 添加什么头文件

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。

[cpp] view plain copy

- (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。

[cpp] view plain copy

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

if (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;

}

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