Question

Is it possible to setup UIImageView to handle image orientation? When I set the UIImageView to image with orientation RIGHT (it is photo from camera roll), the image is rotated to right, but I want to show it in proper orientation, as it was taken.

I know I can rotate image data but it is possible to do it more elegant?

Thank you

69.7k9107125 · Accepted Answer · 2012-01-18 19:05:48Z

54accepted

If I understand, what you want to do is disregard the orientation of the UIImage? If so then you could do this:

UIImage *originalImage = [... whatever ...]; UIImage *imageToDisplay = [UIImage imageWithCGImage:[originalImage CGImage] scale:1.0 orientation: UIImageOrientationUp];

So you're creating a new UIImage with the same pixel data as the original (referenced via its CGImage property) but you're specifying an orientation that doesn't rotate the data.

answered

Jan 18 '12 at 19:05

69.7k9107125

1

By the way, how can I actually rotate the image data? –

3

I guess you'd create a suitably sized CGContext with CGBitmapContextCreate (or with theUIGraphicsBeginImageContext shorthand), use CGContextRotateCTM to set a rotation, use eitherdrawInRect: on the UIImage or CGContextDrawImage with the image's CGImage property, then convert the context to an image either with UIGraphicsGetImageFromCurrentImageContext (and, then,UIGraphicsEndImageContext) if you used UIKit to create the context, orCGBitmapContextCreateImage if you were sticking with the Core Graphics. UIKit isn't very thread safe, but the code would be neater. –

Thanks, I've got it over! –

score 20 · Answer 2

As Anomie suggests in their answer , this code will help to fix orientation:

- (UIImage *)fixrotation:(UIImage *)image{ if (image.imageOrientation == UIImageOrientationUp) return image; CGAffineTransform transform = CGAffineTransformIdentity; switch (image.imageOrientation) { case UIImageOrientationDown: case UIImageOrientationDownMirrored: transform = CGAffineTransformTranslate(transform, image.size.width, image.size.height); transform = CGAffineTransformRotate(transform, M_PI); break; case UIImageOrientationLeft: case UIImageOrientationLeftMirrored: transform = CGAffineTransformTranslate(transform, image.size.width, 0); transform = CGAffineTransformRotate(transform, M_PI_2); break; case UIImageOrientationRight: case UIImageOrientationRightMirrored: transform = CGAffineTransformTranslate(transform, 0, image.size.height); transform = CGAffineTransformRotate(transform, -M_PI_2); break; case UIImageOrientationUp: case UIImageOrientationUpMirrored: break; } switch (image.imageOrientation) { case UIImageOrientationUpMirrored: case UIImageOrientationDownMirrored: transform = CGAffineTransformTranslate(transform, image.size.width, 0); transform = CGAffineTransformScale(transform, -1, 1); break; case UIImageOrientationLeftMirrored:

4 Answers