- (UIImage*)fixOrientation:(UIImage*)aImage {
// No-op if the orientation is already correct
if(aImage.imageOrientation== UIImageOrientationUp)
returnaImage;
// We need to calculate the proper transformation to make the image upright.
// We do it in 2 steps: Rotate if Left/Right/Down, and then flip if Mirrored.
CGAffineTransform transform = CGAffineTransformIdentity;
switch(aImage.imageOrientation) {
caseUIImageOrientationDown:
caseUIImageOrientationDownMirrored:
transform = CGAffineTransformTranslate(transform, aImage.size.width, aImage.size.height);
transform = CGAffineTransformRotate(transform, M_PI);
break;
caseUIImageOrientationLeft:
caseUIImageOrientationLeftMirrored:
transform = CGAffineTransformTranslate(transform, aImage.size.width,0);
transform = CGAffineTransformRotate(transform, M_PI_2);
break;
caseUIImageOrientationRight:
caseUIImageOrientationRightMirrored:
transform = CGAffineTransformTranslate(transform,0, aImage.size.height);
transform = CGAffineTransformRotate(transform, -M_PI_2);
break;
default:
break;
}
switch(aImage.imageOrientation) {
caseUIImageOrientationUpMirrored:
caseUIImageOrientationDownMirrored:
transform = CGAffineTransformTranslate(transform, aImage.size.width,0);
transform = CGAffineTransformScale(transform, -1,1);
break;
caseUIImageOrientationLeftMirrored:
caseUIImageOrientationRightMirrored:
transform = CGAffineTransformTranslate(transform, aImage.size.height,0);
transform = CGAffineTransformScale(transform, -1,1);
break;
default:
break;
}
// Now we draw the underlying CGImage into a new context, applying the transform
// calculated above.
CGContextRef ctx = CGBitmapContextCreate(NULL, aImage.size.width, aImage.size.height,
CGImageGetBitsPerComponent(aImage.CGImage),0,
CGImageGetColorSpace(aImage.CGImage),
CGImageGetBitmapInfo(aImage.CGImage));
CGContextConcatCTM(ctx, transform);
switch(aImage.imageOrientation) {
caseUIImageOrientationLeft:
caseUIImageOrientationLeftMirrored:
caseUIImageOrientationRight:
caseUIImageOrientationRightMirrored:
// Grr...
CGContextDrawImage(ctx, CGRectMake(0,0,aImage.size.height,aImage.size.width), aImage.CGImage);
break;
default:
CGContextDrawImage(ctx, CGRectMake(0,0,aImage.size.width,aImage.size.height), aImage.CGImage);
break;
}
// And now we just create a new UIImage from the drawing context
CGImageRef cgimg = CGBitmapContextCreateImage(ctx);
UIImage*img = [UIImageimageWithCGImage:cgimg];
CGContextRelease(ctx);
CGImageRelease(cgimg);
returnimg;
}