rotateImage

+(UIImage *)rotateImage:(UIImage *)aImage
{
         CGImageRef imgRef = aImage.CGImage;
         CGFloat width = CGImageGetWidth(imgRef);
         CGFloat height = CGImageGetHeight(imgRef);
        
         CGAffineTransform transform = CGAffineTransformIdentity;
         CGRect bounds = CGRectMake(0, 0, width, height);
        
         CGFloat scaleRatio = 1;
        
         CGFloat boundHeight;
         UIImageOrientation orient = aImage.imageOrientation;
         switch(orient)
         {
              case UIImageOrientationUp: //EXIF = 1
                     transform = CGAffineTransformIdentity;
                     break;
                    
              case UIImageOrientationUpMirrored: //EXIF = 2
                     transform = CGAffineTransformMakeTranslation(width, 0.0);
                     transform = CGAffineTransformScale(transform, -1.0, 1.0);
                     break;
                    
              case UIImageOrientationDown: //EXIF = 3
                     transform = CGAffineTransformMakeTranslation(width, height);
                     transform = CGAffineTransformRotate(transform, M_PI);
                     break;
                    
              case UIImageOrientationDownMirrored: //EXIF = 4
                     transform = CGAffineTransformMakeTranslation(0.0, height);
                     transform = CGAffineTransformScale(transform, 1.0, -1.0);
                     break;
                    
              case UIImageOrientationLeftMirrored: //EXIF = 5
                     boundHeight = bounds.size.height;
                     bounds.size.height = bounds.size.width;
                     bounds.size.width = boundHeight;
                     transform = CGAffineTransformMakeTranslation(height, width);
                     transform = CGAffineTransformScale(transform, -1.0, 1.0);
                     transform = CGAffineTransformRotate(transform, 3.0 * M_PI / 2.0);
                     break;
                    
              case UIImageOrientationLeft: //EXIF = 6
                     boundHeight = bounds.size.height;
                     bounds.size.height = bounds.size.width;
                     bounds.size.width = boundHeight;
                     transform = CGAffineTransformMakeTranslation(0.0, width);
                     transform = CGAffineTransformRotate(transform, 3.0 * M_PI / 2.0);
                     break;
                    
              case UIImageOrientationRightMirrored: //EXIF = 7
                     boundHeight = bounds.size.height;
                     bounds.size.height = bounds.size.width;
                     bounds.size.width = boundHeight;
                     transform = CGAffineTransformMakeScale(-1.0, 1.0);
                     transform = CGAffineTransformRotate(transform, M_PI / 2.0);
                     break;
                    
              case UIImageOrientationRight: //EXIF = 8
                     boundHeight = bounds.size.height;
                     bounds.size.height = bounds.size.width;
                     bounds.size.width = boundHeight;
                     transform = CGAffineTransformMakeTranslation(height, 0.0);
                     transform = CGAffineTransformRotate(transform, M_PI / 2.0);
                     break;
                    
              default:
                     [NSException raise:NSInternalInconsistencyException format:@"Invalid image orientation"];
         }
        
         UIGraphicsBeginImageContext(bounds.size);
        
         CGContextRef context = UIGraphicsGetCurrentContext();
        
         if (orient == UIImageOrientationRight || orient == UIImageOrientationLeft) {
              CGContextScaleCTM(context, -scaleRatio, scaleRatio);
              CGContextTranslateCTM(context, -height, 0);
         }
         else {
              CGContextScaleCTM(context, scaleRatio, -scaleRatio);
              CGContextTranslateCTM(context, 0, -height);
         }
        
         CGContextConcatCTM(context, transform);
        
         CGContextDrawImage(UIGraphicsGetCurrentContext(), CGRectMake(0, 0, width, height), imgRef);
         UIImage *imageCopy = UIGraphicsGetImageFromCurrentImageContext();
         UIGraphicsEndImageContext();
        
         return imageCopy;
}