iOS图片灰色处理

代码如下

CGColorSpaceRef colorref = CGColorSpaceCreateDeviceGray();CGContextRef ctx = CGBitmapContextCreate(nil, img.size.width, img.size.height, 8, 0, colorref, kCGImageAlphaNone);CGColorSpaceRelease(colorref);CGContextDrawImage(ctx, CGRectMake(0, 0, img.size.width, img.size.height), img.CGImage);UIImage *imgg = [UIImage imageWithCGImage:CGBitmapContextCreateImage(ctx)];CGContextRelease(ctx);

效果如下

–> 原图

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–> 灰色图

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