Zoom two UIScrollViews synchronously. - ios

Question

I have two UIScrollViews. Both the scroll views contain an image. Now, I want to zoom second scroll view programmatically if I zoom in the first scroll view manually. I am using -(UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView method to manually zoom the first scroll view. The second scroll view should be zoomed to the same point and scale. How can I achieve this?

Answer 1

By using the tag or object of those two scrollviews you can identify the which scroll view you need zoom in viewForZoomingInScrollView method.
e.g
//need to set the tag for scrollviews
-(UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView
{
if(scrollView.tag == 1)
{
return firstImageView;
}
return secondImageView;
}
OR
//need to create the object of used scrollviews
-(UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView
{
if(scrollView == objScrollViewFirst)
{
return firstImageView;
}
return secondImageView;
}

Answer 2

How about something like this:
CGRect zoomRect;
zoomRect.size.height = manualScrollView.frame.size.height / manualScrollView.zoomScale;
zoomRect.size.width = manualScrollView.frame.size.width / manualScrollView.zoomScale;
zoomRect.origin.x = manualScrollView.center.x - (zoomRect.size.width / 2.0);
zoomRect.origin.y = manualScrollView.center.y - (zoomRect.size.height / 2.0);
[autoScrollView zoomToRect:zoomRect animated:YES];
[autoScrollView setZoomScale:manualScrollView.zoomScale animated:YES];

Answer 3

Try something like this in the UIScrollViewDelegate method:
override func scrollViewDidScroll(scrollView: UIScrollView){
otherScrollView.contentOffset = scrollView.contentOffset
otherScrollView.zoomScale = scrollView.zoomScale
}