4.5 KiB
DPI scaling
Qubes OS passes on dom0's screen resolution to VMs (this can be seen in the output of xrandr
) but doesn't pass on dom0's dpi value. Recent distributions have automatic scaling depending on the screen's resolution (eg. in fedora if the screen resolution is at least 192dpi and the screen height is greater than 1200 pixels) but for a variety of reasons one may have to set a custom dpi scaling value.
Dom0
The simplest way to set dpi scaling in dom0 is to use the desktop environment's custom dpi feature:
- Xfce: Qubes Menu → System Tools → Appearance → Fonts tab: Custom DPI setting:
xxx
- KDE: Qubes Menu → System Settings → Font → Force font dpi:
xxx
Replace xxx
with a number that fits your setup and is a multiple of 6, as numbers that aren't sometimes result in annoying rounding errors that cause adjacent bitmap font sizes to not increment and decrement linearly.
VMs
The procedure for setting DPI scaling is different depending on whether gnome settings daemon is running or not:
- if the daemon is stopped/not installed, applications honor the
Xft.dpi
X resource which we can then use for scaling. - if the daemon is running (
/usr/libexec/gsd-xsettings
process in Fedora), applications are prevented from using theXft.dpi
resource anddconf
values have to set.
Notes:
- the official
fedora-xx
template has thegnome-settings-daemon
rpm installed by default while thefedora-xx-minimal
template doesn't. - DPI scaling with
xterm
(or any glib apps) requires the use of a xft font:-
for
xterm
, ctrl - right click in the terminal's windows and select 'TrueType Fonts' (make sure you have such fonts installed). -
or more generally, set the
faceName
Xresource, eg.:*faceName: DejaVu Sans Mono:size=14:antialias=true
You may do so temporarily with the
xrdb -merge
command, or permanently in aXresources
file (see section below).
-
VMs without gnome settings daemon
Get the current value of Xft.dpi
:
xrdb -query | grep Xft.dpi
Test with a different dpi value: in a terminal issue the following command and then start an application to check that the menus/fonts' size is increased/decreased; replace '144' with the value set in dom0 (it's possible to set a different value in VMs though):
echo Xft.dpi: 144 | xrdb -merge
Once you found a value that fits your setup you'll likely want to permanently set the Xft.dpi
resource. You can do so on a per-template (system-wide) or per-VM basis:
- add (or modify)
Xft.dpi: xxx
in the TemplateVM's Xresource file (/etc/X11/Xresources
or/etc/X11/Xresources/x11-common
for whonix-ws-template). - or, add
Xft.dpi: xxx
to$HOME/.Xresources
in each AppVM.
VMs with gnome settings daemon
We'll set the scaling-factor
and text-scaling-factor
dconf values in the org.gnome.desktop.interface
schema.
Get the current values:
gsettings get org.gnome.desktop.interface scaling-factor
gsettings get org.gnome.desktop.interface text-scaling-factor
Test with different values; notes:
- windows and menu/fonts should be resized dynamically
- when running the commands below the values will be automatically written to
$HOME/.config/dconf/user
- replace
2
and0.75
to suit your needs (scaling-factor
must be an integer though)
gsettings set org.gnome.desktop.interface scaling-factor 2
gsettings set org.gnome.desktop.interface text-scaling-factor 0.75
If gsd-xsettings
is running but nothing happens, examine the output of dconf dump /
. If needed, reset any xsettings
override:
gsettings reset org.gnome.settings-daemon.plugins.xsettings overrides
To store the dconf values system-wide - eg. when customizing templateVMs - copy the following text into /etc/dconf/db/local.d/dpi
(replace 2
and 0.75
with your values):
[org/gnome/desktop/interface]
scaling-factor=uint32 2
text-scaling-factor=0.75
Then run dconf update
.
For more information on setting system-wide dconf values see this page.
Resources
- ARCH Linux HiDPI wiki page: https://wiki.archlinux.org/index.php/HiDPI
- Gnome HiDPI wiki page: https://wiki.gnome.org/HowDoI/HiDpi
- Mozilla DPI-related Font Size Issues on Unix: https://www-archive.mozilla.org/unix/dpi.html
- Related official issue: https://github.com/QubesOS/qubes-issues/issues/1951
Contributors: @taradiddles