OC图片模糊效果（一）

引用IOS自带framework中的Accelerate

实现代码为：
image是图片，ratio是模糊度

• (UIImage *)bufImage:(UIImage *)image withRatio:(CGFloat)ratio;
  {
  if (image == nil)
  {
  NSLog(@"image不能为空");
  return nil;
  }
  int bufSize = (int)(ratio * 100);
  bufSize -= (bufSize % 2) + 1;
  if (bufSize < 1) {
  bufSize = 1;
  }
  NSLog(@"bufSize:%i",bufSize);
  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));
  outBuffer.data = pixelBuffer;
  outBuffer.width = CGImageGetWidth(img);
  outBuffer.height = CGImageGetHeight(img);
  outBuffer.rowBytes = CGImageGetBytesPerRow(img);

  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);

  error = vImageBoxConvolve_ARGB8888(&inBuffer, &outBuffer2, NULL, 0, 0, bufSize, bufSize, NULL, kvImageEdgeExtend);
  error = vImageBoxConvolve_ARGB8888(&outBuffer2, &inBuffer, NULL, 0, 0, bufSize, bufSize, NULL, kvImageEdgeExtend);
  error = vImageBoxConvolve_ARGB8888(&inBuffer, &outBuffer, NULL, 0, 0, bufSize, bufSize, NULL, kvImageEdgeExtend);
  if (error) {
  NSLog(@"error from convolution %ld", error);
  }

  //颜色空间DeviceRGB
  CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
  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];
  //释放
  CGContextRelease(ctx);
  CGColorSpaceRelease(colorSpace);
  free(pixelBuffer);
  free(pixelBuffer2);
  CFRelease(inBitmapData);
  CGImageRelease(imageRef);
  return returnImage;
  }