Firefox DPI scaling
Is there any way (as in Thunderbird, via layouts.css.devPixelsperPx) to enlarge everything on a given monitor/display/colorDepth setting? Or an approach using userChrome.css that impacts everything, not just displayed text in the browser. Yes, this is a "tired old eyes" (excessive nanoseconds spent looking at bigger and bigger displays with higher and higher resolution) type question. My setup is multiple boot OS including Windows 11, Ubuntu, Manjaro, Arch. In each Firefox is the default browser, but Chrome and Edge seem to have more fine-grained controls for managing the chrome display than Mozilla. Using the latest 64-bit Firefox (100.02) if that's helpful.
Chosen solution
You can set layout.css.devPixelsPerPx to 1.0 (default is -1) on the about:config page. Adjust its value in 0.1 or 0.05 steps (1.1 to enlarge or 0.9 to reduce) until icons or text looks right. You may need values above 2.0 if you have a high resolution display but make sure not to use values too large or too small.
- modifying layout.css.devPixelsPerPx affects user interface and webpages (global zoom)
Firefox has a Zoom section in Settings to set the default zoom level for webpages.
- Settings -> General -> Language and Appearance -> Zoom
You can open the about:config page via the location/address bar. If you get the warning page, you can click the "Accept the Risk and Continue" button.
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enlarge everything on a given monitor/display/colorDepth setting? I'm not smart enough to understand your full intent per above ... other than to ask IF you use Zoom (clk 3-Bars Menu far Rt (for me)/ Zoom % ..... what beyond that are you wanting to change-enlarge.
See attached screenshot of Thunderbird, which has a setting `layout.css.devPixelsperpx` that renders all (not just the "content" but the "chrome" as well) much more readable on this particular display config.
Chosen Solution
You can set layout.css.devPixelsPerPx to 1.0 (default is -1) on the about:config page. Adjust its value in 0.1 or 0.05 steps (1.1 to enlarge or 0.9 to reduce) until icons or text looks right. You may need values above 2.0 if you have a high resolution display but make sure not to use values too large or too small.
- modifying layout.css.devPixelsPerPx affects user interface and webpages (global zoom)
Firefox has a Zoom section in Settings to set the default zoom level for webpages.
- Settings -> General -> Language and Appearance -> Zoom
You can open the about:config page via the location/address bar. If you get the warning page, you can click the "Accept the Risk and Continue" button.
Modified by cor-el
I'm going to mark this as solved, but I could swear this setting sometimes gets overwritten during updates?
Normally you should keep changes you make to prefs on the about:config page and this pref has always been around and won't be removed. If you lose pref settings then you either have created a new profile folder or you have security software that interferes and corrupts prefs.js that stores those settings.