iOS小demo之图片变灰

//用于对图片处理让图片变成灰色

-(UIImage*)addMaskingToImage:(UIImage*)image{
int bitmapInfo =
kCGImageAlphaNone;
int width = image.size.width;
int height = image.size.height;
CGColorSpaceRef colorSpace =
CGColorSpaceCreateDeviceGray();
CGContextRef context =
CGBitmapContextCreate(nil,
width,
height,

8,//bitpercomp

0, colorSpace, bitmapInfo);
CGColorSpaceRelease(colorSpace);
if (context ==
NULL) {
return
nil;
}
CGContextDrawImage(context,
CGRectMake(0,
0, width, height), image.CGImage);
UIImage *newImage = [UIImage
imageWithCGImage:CGBitmapContextCreateImage(context)];
CGContextRelease(context);
return newImage;
}

关于CGBitmapContextCreate方法：详细请看