1903731 - PDF with non-integer DW is not rendered correctly

Status: VERIFIED FIXED

(Firefox :: PDF Viewer, defect, P1)

Description

[Erdal Alacali]

Attachment: Firefox PDF Viewer Bug.zip

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/126.0.0.0 Safari/537.36

Steps to reproduce:

Open an existing PDF document in Firefox

Actual results:

The PDF document is not displayed correctly, the fonts have different widths, therefore some parts of the PDF document are not displayed correctly, see attached screenshot file "Firefox-127-PDF-Screen.png".

Expected results:

The Firefox viewer should display the file correctly and display the font widths correctly.
Other browsers such as chrome, edge display the file correctly, and Firefox should also display it correctly.
Attached is the affected PDF file and the screenshots of the PDF viewers in question (in the browsers).
Further in the attachment you will find an info screenshot of the Firefox version.

Comment 1

[BugBot [:suhaib / :marco/ :calixte]]

The Bugbug bot thinks this bug should belong to the 'Firefox::PDF Viewer' component, and is moving the bug to that component. Please correct in case you think the bot is wrong.

Comment 2

[Andre Klapper]

Same result as in Firefox in Evince 46.3/Poppler 24.02.
Cannot reproduce in xpdf 4.04, same result as in Chromium based browsers like Edge.

I don't see how that is a Firefox problem - that's rather whether fonts are embedded in the PDF or if not if they are available on your system and if not which font your system falls back to.

Comment 3

[Calixte Denizet (:calixte)]

:Andre Klapper, why did you close this bug ?
For your information, the bug is in the pdf itself because a font uses a non-integer DW which must be an integer (because of the pdf specs).
But in considering that the rendering is correct in either Chrome or Acrobat, it's something we must fix in pdf.js.

Comment 4

[Calixte Denizet (:calixte)]

Attachment: 54428.pdf

Comment 5

[BMO Github Automation]

Attachment: [mozilla/pdf.js] Always use DW if it's a number for the font default width (bug 1903731) (#18306)

Comment 6

[Reinhard Herzfeld]

As an additional information, the provided PDF file was good prior to Firefox version 127. Only after the update to 127, this has been perceived.

Comment 7

[Marco Castelluccio [:marco]]

Could you try using https://mozilla.github.io/mozregression/ to figure out what caused the problem?

Comment 8

[Calixte Denizet (:calixte)]

It's a regression from bug 1894705 and especially from:
https://github.com/mozilla/pdf.js/pull/18017

Comment 9

[BugBot [:suhaib / :marco/ :calixte]]

Set release status flags based on info from the regressing bug 1894705

Comment 10

[Donal Meehan [:dmeehan]]

:calixte is there anything you can patch here in an uplift request for Fx28, or should this ride the train with Fx129?

Comment 11

[Calixte Denizet (:calixte)]

Attachment: Bug 1903731 - Always use DW if it's a number for the font default width

Comment 12

[Phabricator Automation]

beta Uplift Approval Request

• User impact if declined: Small
• Code covered by automated testing: yes
• Fix verified in Nightly: no
• Needs manual QE test: yes
• Steps to reproduce for manual QE testing: See comment#0
• Risk associated with taking this patch: Very small
• Explanation of risk level: One line and can easily be verified
• String changes made/needed: no
• Is Android affected?: no

Comment 13

[Calixte Denizet (:calixte)]

Having a non-integer default width is likely not so common, but in considering the complexity of the patch I think it's better to uplift it.

Comment 14

[Pulsebot]

https://hg.mozilla.org/releases/mozilla-beta/rev/4435a474fcf8

Comment 15

[Peter Magyari (Desktop QA)]

Verified fixed using Beta 128.0b8 (20240625205049) and Nightly 129.0a1 (20240625213230) on MacOS 14, Ubuntu 24.04 and Windows 10.