iOS 毛玻璃 效果實現

//加模糊效果，image是圖片，blur是模糊度


(UIImage )blurryImage:(UIImage )image withBlurLevel:(CGFloat)blur {
//模糊度,
if ((blur < 0.1f) || (blur > 2.0f)) {

  blur = 0.5f;


}



//boxSize必須大于0

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

boxSize -= (boxSize % 2) + 1;

NSLog(@"boxSize:%i",boxSize);

//圖像處理

CGImageRef img = image.CGImage;

//需要引入#import <Accelerate/Accelerate.h>

/*

 This document describes the Accelerate Framework, which contains C APIs for vector and matrix math, digital signal processing, large number handling, and image processing.

 本文檔介紹了Accelerate Framework，其中包含C語言應用程序接口（API）的向量和矩陣數學，數字信號處理，大量處理和圖像處理。

 */



//圖像緩存,輸入緩存，輸出緩存

vImage_Buffer inBuffer, outBuffer;

vImage_Error error;

//像素緩存

void *pixelBuffer;



//數據源提供者，Defines an opaque type that supplies Quartz with data.

CGDataProviderRef inProvider = CGImageGetDataProvider(img);

// provider’s data.

CFDataRef inBitmapData = CGDataProviderCopyData(inProvider);



//寬，高，字節/行，data

inBuffer.width = CGImageGetWidth(img);

inBuffer.height = CGImageGetHeight(img);

inBuffer.rowBytes = CGImageGetBytesPerRow(img);

inBuffer.data = (void*)CFDataGetBytePtr(inBitmapData);



//像數緩存，字節行*圖片高

pixelBuffer = malloc(CGImageGetBytesPerRow(img) * CGImageGetHeight(img));



outBuffer.data = pixelBuffer;

outBuffer.width = CGImageGetWidth(img);

outBuffer.height = CGImageGetHeight(img);

outBuffer.rowBytes = CGImageGetBytesPerRow(img);





// 第三個中間的緩存區,抗鋸齒的效果

void *pixelBuffer2 = malloc(CGImageGetBytesPerRow(img) * CGImageGetHeight(img));

vImage_Buffer outBuffer2;

outBuffer2.data = pixelBuffer2;

outBuffer2.width = CGImageGetWidth(img);

outBuffer2.height = CGImageGetHeight(img);

outBuffer2.rowBytes = CGImageGetBytesPerRow(img);



//Convolves a region of interest within an ARGB8888 source image by an implicit M x N kernel that has the effect of a box filter.

error = vImageBoxConvolve_ARGB8888(&inBuffer, &outBuffer2, NULL, 0, 0, boxSize, boxSize, NULL, kvImageEdgeExtend);

error = vImageBoxConvolve_ARGB8888(&outBuffer2, &inBuffer, NULL, 0, 0, boxSize, boxSize, NULL, kvImageEdgeExtend);

error = vImageBoxConvolve_ARGB8888(&inBuffer, &outBuffer, NULL, 0, 0, boxSize, boxSize, NULL, kvImageEdgeExtend);





if (error) {

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

}




//    NSLog(@"字節組成部分：%zu",CGImageGetBitsPerComponent(img));

//顏色空間DeviceRGB

CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();

//用圖片創建上下文,CGImageGetBitsPerComponent(img),7,8

CGContextRef ctx = CGBitmapContextCreate(

                                         outBuffer.data,

                                         outBuffer.width,

                                         outBuffer.height,

                                         8,

                                         outBuffer.rowBytes,

                                         colorSpace,

                                         CGImageGetBitmapInfo(image.CGImage));



//根據上下文，處理過的圖片，重新組件

CGImageRef imageRef = CGBitmapContextCreateImage (ctx);

UIImage *returnImage = [UIImage imageWithCGImage:imageRef];



//clean up

CGContextRelease(ctx);

CGColorSpaceRelease(colorSpace);



free(pixelBuffer);

free(pixelBuffer2);

CFRelease(inBitmapData);



CGColorSpaceRelease(colorSpace);

CGImageRelease(imageRef);



return returnImage;


}</pre>