/**

 UIImage:去色功能的实现（图片灰色显示）

 @param sourceImage 图片

 */

- (UIImage *)grayImage:(UIImage *)sourceImage

{

   int bitmapInfo = kCGImageAlphaNone;

   int width = sourceImage.size.width;

   int height = sourceImage.size.height;

   CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceGray();

   CGContextRef context = CGBitmapContextCreate (nil,width,height,,,colorSpace,bitmapInfo);

   CGColorSpaceRelease(colorSpace);

   if (context == NULL) {

       return nil;

   }

   CGContextDrawImage(context,CGRectMake(, , width, height), sourceImage.CGImage);

   UIImage *grayImage = [UIImage imageWithCGImage:CGBitmapContextCreateImage(context)];

   CGContextRelease(context);

   return grayImage;

}