Converting to B&W and then back to colour?

[ChrisYates]

I'm thinking that this is probably not possible but let's say the user converts a photo to B&W by tapping a button, is it possible to undo that action and make it colour again!?

Here's the code I'm using for B&W conversion:

UIImage *originalImage = photo1Holder.image; // this image we get from UIImagePickerController
    
    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceGray();
    CGContextRef context = CGBitmapContextCreate(nil, originalImage.size.width, originalImage.size.height, 8, originalImage.size.width, colorSpace, 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(colorSpace);
    
    photo1Holder.image = [UIImage imageWithCGImage:bwImage]; // This is result B/W image.
    CGImageRelease(bwImage);

[architectpianist]

Why not just make originalImage a property in your .h file? Then you can just revert back with

photo1Holder.image = self.originalImage;

But without saving the originalImage, I don't think it's possible.

[ChrisYates]

The problem I'm having is the user picks the image from their photo library.

[Duncan C]

Originally Posted by ChrisYates

The problem I'm having is the user picks the image from their photo library.

So make a copy of the original before doing the B&W conversion. Then if they decide to revert, go back to the original.