Mobile Chrome crash on Pinch and Zoom > 200% ( Android 13,built in Web View but latest Chrome as well)

[dtrbi]

Hi,

we found one issue with Pinch and Zoom on the mobile Chrome and Android 13. We can reproduce even with https://pdfviewer.net/extended-pdf-viewer/simple. Just try to zoom and it will crash.

We can not reproduce on Firefox Android or any browser on Android 14. As well https://mozilla.github.io/pdf.js/web/viewer.html works on Android 13 and does not crash.

All latest updates are installed on Android 13 device.

Version info

• 21.3.8

Demo PDF file Any .pdf file

Thank you and best regards.

[stephanrauh]

I don't own an Android device, let alone Android 13, so there's little I can do.

However, does this bug occur on https://mozilla.github.io/pdf.js/web/viewer.html or https://mozilla.github.io/pdf.js/legacy/web/viewer.html? If so, it's a bug of the base library, and you can forward it to the pdf.js team.

[dtrbi]

On both https://mozilla.github.io/pdf.js/web/viewer.html and https://mozilla.github.io/pdf.js/legacy/web/viewer.html it is working fine.

But as already said we can reproduce problem on most of Android 13 devices and some of Android 14 (mostly low level) on https://pdfviewer.net/extended-pdf-viewer/simple.

Steps to reproduce:

1. Zoom in/zoom out with pinch and zoom several times

I am pretty sure there is some kind of memory leak.

Thank you for all your hard work and making our life with Angular and PDF.js much easier.

[raphjutras]

I can confirm that we also experience this problem on both Android and iOS.

It will happen when we zoom a lot on the PDF: ex, on construction plans, they are really zoomed-out and to be able to see any detail, the user must pinch to zoom it, more than 200%.

Example PDF file: https://vancouver.ca/files/cov/sample-drawing-package-1and2family.pdf

I have noticed that, while pinch-zooming, the screen will tear and freeze. Our app also crashed when zooming-in-out multiple time (with a bigger PDF plan than the sample provided here). Also, while zoomed, if we move to left-right, some part of the PDF just dissapear/blank. we have to zoom-out then re-zoom in to see it. There is clearly somethign strange happening.

[stephanrauh]

Phew. First of all, sorry for answering late. It's because I'm ill.

However, I still don't know how to solve the issue. I understand there's a difference between my fork of pdf.js and the original that causes crashes. But how to solve that? As I've mentioned earlier, I don't own an Android device, so I'm at a loss. @raphjutras I do own an iOS device, so maybe I can debug the problem, but it's still a major challenge.

Can I talk you into helping me? Does the debugger or the console show anything useful?

[raphjutras]

@stephanrauh I have made a simple test with original pdf.js in my Safari browser (iPhone) by accessing PDF.js official demo: https://mozilla.github.io/pdf.js/web/viewer.html

It seem that the original script suffer from same tearing bug when pinch-zooming a lot.

I havent had the chance to look at debuger/console.

[raphjutras]

Just did a research on PDF.js github, looks like the issue had already been flagged..! https://github.com/mozilla/pdf.js/issues/17713

[dtrbi]

Phew. First of all, sorry for answering late. It's because I'm ill.

Get well soon. Wishing you a speedy recovery. This bug is not so important.

[stephanrauh]

@raphjutras Are your referring to this workaround?

.pdfViewer .canvasWrapper,
.pdfViewer .page canvas[zooming] {
  width: inherit !important;
}

[raphjutras]

@stephanrauh Yes, I will definitely need to give this a try!

[raphjutras]

On both https://mozilla.github.io/pdf.js/web/viewer.html and https://mozilla.github.io/pdf.js/legacy/web/viewer.html it is working fine.

But as already said we can reproduce problem on most of Android 13 devices and some of Android 14 (mostly low level) on https://pdfviewer.net/extended-pdf-viewer/simple. .

I think this might be two separate/different bugs.. Tearing is something, app crashing is something else hehe

[stephanrauh]

Yes, you're right. I hoped it might be the same bug, but it was a wild shot.

[stephanrauh]

What about version 22.0.0? Currently, that's an alpha version, but it's running on a new version of pdf.js. Maybe that solves the issue?

[raphjutras]

Hello @stephanrauh, I have installed 21.4.6 and I still encouter problems when zomming a lot. I tried installing version 22.0.0 by adding this line to my package.json: "ngx-extended-pdf-viewer": "git://github.com/stephanrauh/ngx-extended-pdf-viewer.git#22.0.0-alpha.2"

It successfully installs it, I can see the changes in node_modules folder, however I am unable to build my Angular app after that, it will hrow a lot of errors (about my own components? I don't know why) and the last error is: Error: src/app/shared/shared.module.ts:79:44 - error TS2307: Cannot find module 'ngx-extended-pdf-viewer' or its corresponding type declarations. [ng] [ng] 79 import { NgxExtendedPdfViewerModule } from 'ngx-extended-pdf-viewer';

So I can't really test v22.0.0 on browser or mobile.