Zooming UIImageView inside UIScrollView with autolayout

Question

I have a UIImageView embedded inside a UIScrollView, prior to iOS 6 and autolayout I used the following snippet inside the controller\'s viedDidLoad method to display a scro

Answer 1

I also agree with Zsolt's suggestion and link.

But I update the width/height constraints to allow it to handle any size image:

- (void) initZoom
{
  for (NSLayoutConstraint *constraint in self.photoImageView.constraints)
  {
    if (constraint.firstAttribute == NSLayoutAttributeWidth)
      constraint.constant = self.photoImageView.image.size.width;
    else if (constraint.firstAttribute == NSLayoutAttributeHeight)
      constraint.constant = self.photoImageView.image.size.height;
  }

  float minZoom = MIN(self.scrollView.bounds.size.width / self.photoImageView.image.size.width,
                      self.scrollView.bounds.size.height / self.photoImageView.image.size.height);
  if (minZoom > 1) return;

  self.scrollView.minimumZoomScale = minZoom;

  self.scrollView.zoomScale = minZoom;
}