iOS 毛玻璃 效果实现

//加模糊效果，image是图片，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必须大于0        int boxSize = (int)(blur * 100);        boxSize -= (boxSize % 2) + 1;        NSLog(@"boxSize:%i",boxSize);        //图像处理        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.         本文档介绍了Accelerate Framework，其中包含C语言应用程序接口（API）的向量和矩阵数学，数字信号处理，大量处理和图像处理。         */                //图像缓存,输入缓存，输出缓存        vImage_Buffer inBuffer, outBuffer;        vImage_Error error;        //像素缓存        void *pixelBuffer;                //数据源提供者，Defines an opaque type that supplies Quartz with data.        CGDataProviderRef inProvider = CGImageGetDataProvider(img);        // provider’s data.        CFDataRef inBitmapData = CGDataProviderCopyData(inProvider);                //宽，高，字节/行，data        inBuffer.width = CGImageGetWidth(img);        inBuffer.height = CGImageGetHeight(img);        inBuffer.rowBytes = CGImageGetBytesPerRow(img);        inBuffer.data = (void*)CFDataGetBytePtr(inBitmapData);                //像数缓存，字节行*图片高        pixelBuffer = malloc(CGImageGetBytesPerRow(img) * CGImageGetHeight(img));                outBuffer.data = pixelBuffer;        outBuffer.width = CGImageGetWidth(img);        outBuffer.height = CGImageGetHeight(img);        outBuffer.rowBytes = CGImageGetBytesPerRow(img);                        // 第三个中间的缓存区,抗锯齿的效果        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(@"字节组成部分：%zu",CGImageGetBitsPerComponent(img));        //颜色空间DeviceRGB        CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();        //用图片创建上下文,CGImageGetBitsPerComponent(img),7,8        CGContextRef ctx = CGBitmapContextCreate(                                                 outBuffer.data,                                                 outBuffer.width,                                                 outBuffer.height,                                                 8,                                                 outBuffer.rowBytes,                                                 colorSpace,                                                 CGImageGetBitmapInfo(image.CGImage));                //根据上下文，处理过的图片，重新组件        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;    }