# When Form auto-zoom on Mobile the Pinch doesn't work well

**URL:** <https://pdfjs.community/t/when-form-auto-zoom-on-mobile-the-pinch-doesnt-work-well/1866>\
**Category:** Technical Support\
**Tags:** pdfjs-express\
**Created:** [July 13, 2022, 7:23am UTC](https://pdfjs.community/t/when-form-auto-zoom-on-mobile-the-pinch-doesnt-work-well/1866 "2022-07-13T07:23:57Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![luis.perezsanchez](https://yyz1.discourse-cdn.com/flex031/user_avatar/pdfjs.community/luis.perezsanchez/32/726_2.png) [@luis.perezsanchez](https://pdfjs.community/u/luis.perezsanchez)\
**Post date:** [July 13, 2022, 7:23am UTC](https://pdfjs.community/t/when-form-auto-zoom-on-mobile-the-pinch-doesnt-work-well/1866/1 "2022-07-13T07:23:57Z")

</div>

**Which product are you using?**  
PDF.js Express Plus. (domain: [kopjra.com](http://kopjra.com))

**PDF.js Express Version**  
UI version: ‘8.1.0’  
Core version: ‘8.1.1’  
Build: ‘MTAvMjEvMjAyMXw2OGY2MTQ1NWU=’

**Detailed description of issue**  
In mobile when the text field is tapped for text input there is a zoom to that text field. If one tries to zoom out using pinch it does not work, and sends the PDF in the viewer to a strange position and from there even the scroll is kind of lost. The only way to zoom out when in that position is usgin a double tap. This problem is more evident when using Safari on IOS, but it happens in Android with Chrome also.

**Expected behaviour**  
We would expect the tap to work as it usually does. Thus zooming out the PDF in a controlled way without any jumps to strange position.

**Does your issue happen with every document, or just one?**  
It happens on every document with a form

**Code snippet**  
Here you can see a working integration from pur part:  
[http://demo-pdfjsexpress.kopjra.com.s3-website-eu-west-1.amazonaws.com/](http://demo-pdfjsexpress.kopjra.com.s3-website-eu-west-1.amazonaws.com/)

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<div class="post-metadata">

**Author:** ![system](https://canada1.discourse-cdn.com/flex031/uploads/pdfjscommunity/original/1X/ffbcd25c7d423db8d5acd5db201c272f4db306dd.png) [@system](https://pdfjs.community/u/system)\
**Post date:** [July 13, 2022, 7:24am UTC](https://pdfjs.community/t/when-form-auto-zoom-on-mobile-the-pinch-doesnt-work-well/1866/3 "2022-07-13T07:24:02Z")

</div>

**Hello, I’m Ron, an automated tech support bot 🤖**

While you wait for one of our customer support representatives to get back to you, please check out some of these documentation pages:

Guides:
- [PDF.js Express Plus Overview - What is PDF.js Express Plus?](https://pdfjs.express/documentation/get-started#what-is-pdf.js-express-plus?)
- [PDF.js Express Documentation - Our Products - PDF.js Express Plus](https://pdfjs.express/documentation#pdf.js-express-plus)
- [Adding your license key - PDF.js Express Plus License Keys](https://pdfjs.express/documentation/get-started/add-license-key#pdf.js-express-plus-license-keys-<span-class='plus'></span>)

APIs:
- [PDF.js Express Utilities](https://pdfjs.express/api/utils/index.html#__anchor)
- [ExpressUtils(optionsopt) - # async extract() → {Promise.}](https://pdfjs.express/api/utils/ExpressUtils.html#extract__anchor)
- [Core.Tools.MarqueeZoomTool](https://pdfjs.express/api/Core.Tools.MarqueeZoomTool.html#__anchor)

Forums:
- [Manage zoom in mobile using pinch](https://pdfjs.community/t/manage-zoom-in-mobile-using-pinch/1523/1)
- [Not able to validated the license on hybrid mobile app](https://pdfjs.community/t/not-able-to-validated-the-license-on-hybrid-mobile-app/1156/1)
- [Problem retrieving annotations from sqlite3](https://pdfjs.community/t/problem-retrieving-annotations-from-sqlite3/1617/1)

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<div class="post-metadata">

**Author:** ![tgordon](https://avatars.discourse-cdn.com/v4/letter/t/aca169/32.png) [@tgordon](https://pdfjs.community/u/tgordon)\
**Post date:** [July 13, 2022, 10:27pm UTC](https://pdfjs.community/t/when-form-auto-zoom-on-mobile-the-pinch-doesnt-work-well/1866/4 "2022-07-13T22:27:21Z")

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Hello luis.perezsanchez,

Im unable to reproduce any unintended jumping on our demo website: [PDF.js Viewer Demo | PDF.js Express](https://pdfjs.express/demo)

1. Can you try on there?
2. Do you have any custom code that effects the viewer in any way?
3. Can you provide a video of the jumping?

Best regards,  
Tyler Gordon  
Web Development Support Engineer  
PDFTron