tigervnc headless lxqt session but dpi setting is ignored

[linux user]

I am using tigervnc for a headless lxqt session and would like to increase the dpi. Using changing the "resolution (DPI)" within lxqt's appearance>fonts has no effect (96 was default and bumped it to 200 but restarting the vncserver gave identical results). Anyone aware of how to tweak this? Defining dpi=200 in ~/.config/tigervnc/config also had no effect and no mention of invalid options in ~/.local/state/tigervnc/foo:1.log

For reference, ~/.config/tigervnc/config:

desktop=sandbox

geometry=1920x1080
session=lxqt
localhost
alwaysshared

[Pierre Ossman]

On 16/02/2025 13:47, linux user wrote:
> I am using tigervnc for a headless lxqt session and would like to increase
> the dpi. Using changing the "resolution (DPI)" within lxqt's
> appearance>fonts has no effect (96 was default and bumped it to 200 but
> restarting the vncserver gave identical results). Anyone aware of how to
> tweak this? Defining dpi=200 in ~/.config/tigervnc/config also had no
> effect and no mention of invalid options in
> ~/.local/state/tigervnc/foo:1.log
>

Unfortunately, there is a whole bunch of ways to change font size on
Linux, and different applications will look at different settings.

The dpi setting for TigerVNC sets the low level DPI configured for the
X11 screen. You can see it using xdpyinfo:

$ xdpyinfo | grep dots
resolution: 201x200 dots per inch

Most applications ignore this, though.

The Xft settings are more commonly respected:

$ xrdb -query
Xft.dpi: 96

This is commonly set by your desktop environment. It sounds like you
changed things correctly in LxQt's settings. I'm afraid I don't know why
your applications ignore it.

To make things more complicated, the setting used for "high
DPI"/"retina" displays is an entirely different thing that focuses on a
"scale factor" rather than DPI. If that's what you're after, then
changing DPI will probably not get what you want.

Regards,
--
Pierre Ossman Software Development
Cendio AB https://cendio.com
Teknikringen 8 https://twitter.com/ThinLinc
583 30 Linköping https://facebook.com/ThinLinc
Phone: +46-13-214600

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