iOS处理图片颜色代码

处理图片颜色

(UIImage)grayscale:(UIImage)anImage type:(int)type{
  CGImageRef imageRef = anImage.CGImage;
  size_t width  = CGImageGetWidth(imageRef);
  size_t height = CGImageGetHeight(imageRef);
  size_t bitsPerComponent = CGImageGetBitsPerComponent(imageRef);
  size_t bitsPerPixel = CGImageGetBitsPerPixel(imageRef);
  size_t bytesPerRow = CGImageGetBytesPerRow(imageRef);
  CGColorSpaceRef colorSpace = CGImageGetColorSpace(imageRef);
  CGBitmapInfo bitmapInfo = CGImageGetBitmapInfo(imageRef);
  bool shouldInterpolate = CGImageGetShouldInterpolate(imageRef);
  CGColorRenderingIntent intent = CGImageGetRenderingIntent(imageRef);
  CGDataProviderRef dataProvider = CGImageGetDataProvider(imageRef);
  CFDataRef data = CGDataProviderCopyData(dataProvider);
  UInt8 buffer = (UInt8)CFDataGetBytePtr(data);
  NSUInteger  x, y;
  for (y = 0; y < height; y++) {

  for (x = 0; x < width; x++) {
      UInt8 *tmp;
      tmp = buffer + y * bytesPerRow + x * 4;
      UInt8 red,green,blue;
      red = *(tmp + 0);
      green = *(tmp + 1);
      blue = *(tmp + 2);
      UInt8 brightness;

      switch (type) {
          case 1:
              brightness = (77 * red + 28 * green + 151 * blue) / 256;
              *(tmp + 0) = brightness;
              *(tmp + 1) = brightness;
              *(tmp + 2) = brightness;
              break;
          case 2:
              *(tmp + 0) = red;
              *(tmp + 1) = green * 0.7;
              *(tmp + 2) = blue * 0.4;
              break;
          case 3:
              *(tmp + 0) = 255 - red;
              *(tmp + 1) = 255 - green;
              *(tmp + 2) = 255 - blue;
              break;
          default:
              *(tmp + 0) = red;
              *(tmp + 1) = green;
              *(tmp + 2) = blue;
              break;
      }

  }

}
  CFDataRef effectedData = CFDataCreate(NULL, buffer, CFDataGetLength(data));
  CGDataProviderRef effectedDataProvider = CGDataProviderCreateWithCFData(effectedData);
  CGImageRef effectedCgImage = CGImageCreate(

                                         width, height,
                                         bitsPerComponent, bitsPerPixel, bytesPerRow,
                                         colorSpace, bitmapInfo, effectedDataProvider,
                                         NULL, shouldInterpolate, intent);

UIImage *effectedImage = [[UIImage alloc] initWithCGImage:effectedCgImage];
  CGImageRelease(effectedCgImage);
  CFRelease(effectedDataProvider);
  CFRelease(effectedData);
  CFRelease(data);
  return effectedImage;
}</pre>