Is it possible to have a UIImageView inside of a UIScrollView zoom in and out, but stick to center with Auto Layout?

Question

Long story short, I\'m trying to build functionality similar to Photos.app.

I have a UIScrollView with a UIImageView inside of it set up in the Storyboard. Zooming works

Answer 1

To center the contents, you can take reference from this code snippet:

// To re-center the image after zooming in and zooming out
- (void)centerScrollViewContents
{
 CGSize boundsSize = self.bounds.size;
 CGRect contentsFrame = self.imageView.frame;

 if (contentsFrame.size.width < boundsSize.width)
 {
   contentsFrame.origin.x = (boundsSize.width - contentsFrame.size.width) / 2.0f;
 }
 else
 {
  contentsFrame.origin.x = 0.0f;
 }

 if (contentsFrame.size.height < boundsSize.height)
 {
  contentsFrame.origin.y = (boundsSize.height - contentsFrame.size.height) / 2.0f;
 }
 else
 {
    contentsFrame.origin.y = 0.0f;
 }

 self.imageView.frame = contentsFrame;
}

//for zooming in and zooming out
- (void)scrollViewDidZoom:(UIScrollView *)scrollView
 {
  if (self.zoomScale > 1.0f)
  {
    [self centerScrollViewContents];
  }
   else
  {
  self.bouncesZoom    =   NO;

    // for zooming out by pinching
  [self centerScrollViewContents];
  }

 }

In this way, you can reposition the coordinates of an image after zooming in and zooming out without AutoLayout. Please let me know if it helps. Thanks :)