Ubuntu – How change display scale from the command line in Ubuntu 18.04 (xorg)

18.04gnome-control-centerhdpiscalingxorg

I am trying to get in the command line the same effect as changing the display scale factor from the Gnome Control Center.

I have tried the following command, but it does not have any effect:

gsettings set org.gnome.desktop.interface scaling-factor 2

I need this command to build a sort of fractional scale factor with the combination of xrandx and the scaling factor in the Gnome Control Center. Since, the execution of xrandr resets the scaling factor in the Gnome Control Center, I would need a command to recover the value in the Gnome Control Center.

Please, any suggestion is welcome. Thanks in advance.

Best Answer

Determine your output device (mine is DP-1) by running xrandr on its own, then use this:

gsettings set org.gnome.desktop.interface scaling-factor 2
gsettings set org.gnome.settings-daemon.plugins.xsettings overrides "{'Gdk/WindowScalingFactor': <2>}"
xrandr --output DP-1 --scale 1.5x1.5
xrandr --output DP-1 --panning 3840x2160

Related Solutions

Ubuntu – Gnome 3.16 HiDPI scaling only accepts integers

I checked with my Fedora 21 install where I have Gnome 3.14.2 and it doesn't seem to be possible to set your desired value:

[btegge@za21 ~]$ gsettings set org.gnome.desktop.interface scaling-factor 1.2
invalid character in number:
  1.2
   ^
[btegge@za21 ~]$ gsettings set org.gnome.desktop.interface scaling-factor 1,2
expected end of input:
  1,2
   ^

My assumptions:

There is a another setting to achieve what you want. The only thing that comes to my mind is font rendering related, though that is not exactly what you are looking for.
It's a mistake that the key only accepts integers as datatype and you should file a bug.

Ubuntu – Changing UI scaling from command line

Tl;Dr:
sed -i -e '/<scale>/ s/1/2/' ~/.config/monitors.xml && sudo systemctl restart gdm

Mutter does listen to some settings in Gsettings, and after looking at the code, there is some legacy gsettings support for deprecated settings like gsettings ui-scaling-factor. For other things, it supports using XML for configuration. You'll probably need to Alt+F2, r to restart gnome-shell for settings to apply... or figure out the dbus details from the code.

Here is my config for an old monitor... notice the line... easy to sed

~/.config/monitors.xml
<monitors version="2">
  <configuration>
    <logicalmonitor>
      <x>0</x>
      <y>0</y>
      <scale>1</scale>
      <primary>yes</primary>
      <transform>
        <rotation>upside_down</rotation>
        <flipped>no</flipped>
      </transform>
      <monitor>
        <monitorspec>
          <connector>HDMI-1</connector>
          <vendor>ACR</vendor>
          <product>V226HQL</product>
          <serial>T0WAA0072442</serial>
        </monitorspec>
        <mode>
          <width>1920</width>
          <height>1080</height>
          <rate>60</rate>
        </mode>
      </monitor>
    </logicalmonitor>
  </configuration>

I put together the codes above to do 200x. It works on wayland and X, but will log you out. If you can do ALt+F2,r, that would obviously be better... I tried doing it with a terminal command and just kept crashing gnome. Might use Robot.js or xdotool to send a restart command... like this

xdotool keydown alt && sleep 1 && xdotool key F2 keyup alt && sleep 1 && xdotool key r && sleep 1 && xdotool key KP_Enter

My full version for X11 swap-res.sh... this works on an ubuntu keyboard shortcut too

#!/bin/bash
File=~/.config/monitors.xml
if grep -q "<scale>1" "$File"; then
  sed -i -e '/<scale>1/ s/1/3/' "$File"
else
  sed -i -e '/<scale>3/ s/3/1/' "$File"
fi

# Unix Utils
xdotool keydown alt && sleep 1 && xdotool key F2 keyup alt \
  && sleep 1 && xdotool key r key KP_Enter

Source: https://gitlab.gnome.org/GNOME/mutter/ (quite literally, leave a star!)

Best Answer

Related Solutions

Ubuntu – Gnome 3.16 HiDPI scaling only accepts integers

Ubuntu – Changing UI scaling from command line

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