What method/event will tell me when the PDF is scrolling?

Technical Support WebViewer
1

I’m using the latest version of Webviewer. No server. I just load a PDF. It works fine.

I would like a javascript function called when the user starts and stops scrolling/panning/zooming the PDF. Is this possible? Like whenever the mobile device is panning the PDF pages up or down or whatever, I’d like to set a variable on/off while it happens. Any idea?

2

Hello,
You can achieve this by first obtaining the scroll view element and then attaching an event listener for the ‘scroll’ event. To detect when a user stops scrolling, you can utilize the setTimeout method within the event listener.
The following code snippet should work for scrolling, zooming and panning.

  const { documentViewer } = instance.Core;
  const pdfViewerElement = documentViewer.getScrollViewElement();
  let isScrolling = false; 
  let scrollTimer = null;

  pdfViewerElement.addEventListener('scroll', () => {
    isScrolling = true;
    console.log('scrolling');
    clearTimeout(scrollTimer);

    scrollTimer = setTimeout(() => {
      isScrolling = false;
      console.log('Scrolling stopped');
    }, 150);
  });

Please adjust anything to fit your needs.

Best Regards,
Darian Chen