iPad camera popover preview wrong rotation and scale

问题

I am showing the camera in a popover (on an iPad - the iPad app is locked to Lanscape Left) and the preview is in Portrait and the wrong scale. The code is below - I have worked out the rotation and added it, but the preview size is the too thin now.

   UIImagePickerController *imagePicker = [[UIImagePickerController alloc] init];

   if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera])
   {
    imagePicker.sourceType = UIImagePickerControllerSourceTypeCamera;
    imagePicker.videoQuality = UIImagePickerControllerQualityTypeMedium;
    imagePicker.mediaTypes = [UIImagePickerController availableMediaTypesForSourceType:UIImagePickerControllerSourceTypeCamera];

    CGAffineTransform transformRotation = CGAffineTransformMakeRotation(270 * M_PI/180);

    imagePicker.cameraViewTransform = transformRotation;
    }
    else
    {
       NSLog(@"Camera not available. Using photo library");
       imagePicker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
    }

     imagePicker.delegate = self;
     _photoPopover = [[UIPopoverController alloc] initWithContentViewController:imagePicker];
     [_photoPopover presentPopoverFromRect:view.frame inView:self.view permittedArrowDirections:UIPopoverArrowDirectionUp animated:YES];