使图像变成黑色和白色？

Question

我还有一个石英2D（iphone）问题：

如何将ImageView的所有颜色更改为黑白，只留下红???

DD

Answer 1

UIImage *originalImage = [info objectForKey:UIImagePickerControllerOriginalImage]; this image we get from UIImagePickerController 

    CGColorSpaceRef colorSapce = CGColorSpaceCreateDeviceGray(); 
    CGContextRef context = CGBitmapContextCreate(nil, originalImage.size.width, originalImage.size.height, 8, originalImage.size.width, colorSapce, kCGImageAlphaNone); 
    CGContextSetInterpolationQuality(context, kCGInterpolationHigh); 
    CGContextSetShouldAntialias(context, NO); 
    CGContextDrawImage(context, CGRectMake(0, 0, originalImage.size.width, originalImage.size.height), [originalImage CGImage]); 

    CGImageRef bwImage = CGBitmapContextCreateImage(context); 
    CGContextRelease(context); 
    CGColorSpaceRelease(colorSapce); 

    UIImage *resultImage = [UIImage imageWithCGImage:bwImage]; // This is result B/W image. 
    CGImageRelease(bwImage); 

这一点是我在其他论坛上发现，它似乎工作！