Turning Off Pixel Doubling on Fedora Hi-DPI Screens

Fedora systems come with an X.org configuration which automatically turns on pixel doubling for screens that have a resolution higher than 2560×1440. This has the net effect of making all the UI elements use 4 times as many pixels as they would on a screen with lower resolution. This looks beautiful, as text is rendered with extra room for anti-aliasing, and images display with high resolution. However, the side effect is that you end up being able to display less content since the UI elements and icons are relatively huge in terms of physical real estate. It’s not obvious how to turn this feature off to use every pixel, so here is the magic incantation:

  1. Open a terminal in your X session.
  2. Run “xrandr –dpi 96” (The real number would be 220dpi for a 2880×1800 display that is 331mm x 207mm, but setting this to 96 fools the system into thinking this is a lower resolution screen).
  3. Run “gsettings set org.gnome.desktop.interface scaling-factor 1”.
  4. Run “gsettings set org.gnome.desktop.interface text-scaling-factor 1” (this may not be necessary if you have not changed the default).
  5. You may need to change the mouse tracking speed.

After running the above, you should be able to use every pixel on your high resolution screen. Try not to squint too much.