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dpa
New member
Status: Trending idea

Hello everyone...

I use Firefox a lot of years and i am very happy with the interface.

But i saw that there is no built-in option to change  the Mode of Embedded PDF Viewer in to Dark

Is possible to be implemented in the near Future...?

Thanks in advanced.

20 Comments
Toni
Strollin' around

It gives me an error:

window.PDFViewerApplication is undefined

Fristender
Strollin' around

@heyzsh @Toni 

There is a clunky(image colors reversed) way to have a dark mode in Firefox here: https://www.reddit.com/r/firefox/comments/eztxrw/dark_mode_for_firefoxs_builtin_pdf_viewer/

Basically, you create a subfolder named "chrome" in the Firefox profile directory and then create a userContent.css file in that folder. Then you paste the below contents into userContent.css and set toolkit.legacyUserProfileCustomizations.stylesheets to true in about:config.

#viewerContainer > #viewer .page > .canvasWrapper > canvas {
    filter: grayscale(100%);
    filter: invert(100%);
background-color: #000 !important; } 

 

Toni
Strollin' around

Thank you @Fristender . This finally works. All the best to all!

wolfmaster010
New member

Give us a setting for dark pdf UI again

I love opening pdfs in Firefox. One thing that it used to give was an easy setting to enable dark mode for the UI. Unfortunately, the setting was removed a while ago. I was then able to bypass the issue by setting pdfjs.viewerCssTheme as value 2. Recent updates appear to have disabled this. This forced me how to use Cascading Style Sheets to put the dark UI back in. I know it's likely not the developers' and programmers' faults, but why has Firefox been so set on changing or removing important and/or accessibility settings lately??

Rant aside, I want this setting re-implemented. For me, this setting is an important accessibility setting. My mind constantly wanders away while I'm reading. By having a dark background and UI (example shown in the image), I'm able to focus more on the pdf than the wide screen. Please, put this back in.

Jon
Community Manager
Community Manager

(Note: similar ideas have been merged into this thread)

Agentvirtuel
Contributor

Hello

If you'd like to try (and see) ui.systemUsesDarkTheme

Configuration Editor for Firefox
https://support.mozilla.org/en-US/kb/about-config-editor-firefox#w_adding-preferences
Adding preferences ui.systemUsesDarkTheme Number value 1

https://www.youtube.com/embed/JTkwNDFEViM

Toni
Strollin' around

@Agentvirtuel 

Thanks, but that does not change pdf to black background.

ETL
Strollin' around

@jscher2000 After Firefox v121 the pdfjs.viewerCssTheme pref does not work when resistFingerprinting is enabled.

buhbuhbob
New member

PDF viewing has an "invert colours" option

It would be nice to be able to invert the colours of PDFs, to be able to read white text on black backgrounds. Firefox extensions that invert colours are blocked on PDF viewing.

Jon
Community Manager
Community Manager

(Note: similar ideas have been merged into this thread)