How to optimize content inset of UIScrollView when zoom out.

UIScrollViewDelegate.m

- (void)scrollViewDidZoom:(UIScrollView *)scrollView
{
    UIEdgeInsets inset = self.originalInset;
        
    if (scrollView.zoomScale < 1) {
        inset.top    += scrollView.bounds.size.height - scrollView.contentSize.height;
        inset.left   += scrollView.bounds.size.width - scrollView.contentSize.width;
        inset.bottom += scrollView.bounds.size.height - scrollView.contentSize.height;
        inset.right  += scrollView.bounds.size.width - scrollView.contentSize.width;
    }
    
    scrollView.contentInset = inset;
}