How do I make an exact copy of a UIImage returned from a UIImagePickerController?

Question

I have divergent needs for the image returned from the iPhone camera. My app scales the image down for upload and display and, recently, I added the ability to save the imag

Answer 1

UIImage *newImage = [UIImage imageWithData:UIImagePNGRepresentation(oldImage)];

Answer 2

Copy backing data and rotate it

This question asks a common question about UIImage in a slightly different way. Essentially, you have two related problems - deep copying and rotation. A UIImage is just a container and has an orientation property that is used for display. A UIImage can contain its backing data as a CGImage or CIImage, but most often as a CGImage. The CGImage is a struct of information that includes a pointer to the underlying data and if you read the docs, copying the struct does not copy the data. So...

Deep copying

As I'll get to in the next paragraph deep copying the data will leave the image rotated because the image is rotated in the underlying data.

UIImage *newImage = [UIImage imageWithData:UIImagePNGRepresentation(oldImage)];

This will copy the data but will require setting the orientation property before handing it to something like UIImageView for proper display.

Another way to deep copy would be to draw into the context and grab the result. Assume a zebra.

UIGraphicsBeginImageContext(zebra!.size)
zebra!.drawInRect(CGRectMake(0, 0, zebra!.size.width, zebra!.size.height))
let copy = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()

Deep copy and Rotation

Rotating a CGImage has been already been answered. It also happens that this rotated image is a new CGImage that can be used to create a UIImage.

Answer 3

I think you need to create an image context (CGContextRef). Draw the UIImage.CGImage into the context with method CGContextDrawImage(...), then get the image from the context with CGBitmapContextCreateImage(...). With such routine, I'm sure you can get the real copy of the image you want. Hope it's helped you.

Answer 4

This seems to work but you might face some memory problems depending on what you do with newImage:

CGImageRef newCgIm = CGImageCreateCopy(oldImage.CGImage);
UIImage *newImage = [UIImage imageWithCGImage:newCgIm scale:oldImage.scale orientation:oldImage.imageOrientation];

Answer 5

This should work:

UIImage *newImage = [UIImage imageWithCGImage:oldImage.CGImage];