Per-application window scaling in Xorg for high dpi display

Question

I am running Gnome Shell with a 4k monitor and there are a few applications that I use that don't scale at all with the high resolution.

Here is an example of LMMS, an application that hasn't yet been ported Qt 5, so it doesn't have high dpi scaling capabilities:

^{(Click images to enlarge)}

Is there any way to scale a specific X window without changing the display resolution?

My current solution is to half the dimensions of my display resolution, but this degrades the resolution of every other application that supports proper dpi scaling:

score 34 · Accepted Answer · edited Feb 02 '22 at 09:29

34

I finally managed to find a solution that scales old applications without any noticeable visual or performance degradation.

Thanks to kaueraal, you can now scale old applications using run_scaled. You can obtain the script from either his GitHub page or as part of the xpra package if you are running Arch Linux.

Here is an example of two applications running side by side:

Firefox with HiDPI support on the left
LMMS running with run_scaled on the right

I discovered this script through the Arch Linux Wiki.

edited Feb 02 '22 at 09:29

VasyaNovikov

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answered Mar 18 '17 at 05:54

daxvena

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On Ubuntu you [need to install `xpra`](https://askubuntu.com/a/960041/349837) – Pablo A May 21 '19 at 23:54
This program is consuming CPU really heavily. – L29Ah May 29 '19 at 20:38
This script is somewhat poorly documented, but many errors seems to caused by simply missing dependencies. On ubuntu you might need at least (not exhaustively) these: `apt install xvfb python2.7-cups python2.7-gtkglext1 python-opencv xpra python-pyinotify python2.7-dev; pip2 install setuptools; pip2 install PyOpenGL_accelerate`. It also has opengl and non-opengl mode, one of these might work even in case the other doesn't. – Cray Jan 01 '20 at 20:55
For Ubuntu the default repo `xpra` might be out of date. [This GitHub issue](https://github.com/kaueraal/run_scaled/issues/7) describes what you need to do. – totymedli Apr 03 '20 at 07:04
For anyone looking for a better alternative solution, I'm now using the sway window manager. In my opinion it has the best HiDPI support (especially on mixed DPI multi monitor setups), and properly scales non-DPI aware applications. – daxvena Oct 11 '20 at 00:39
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If you are on arch, the `run_scaled` script now comes with `xpra`, so there is no need to install the aur package – smac89 May 20 '21 at 16:27
Confirming what @smac89 wrote. I've also edited the answer now to incorporate the new information. – VasyaNovikov Feb 02 '22 at 09:30

score 9 · Answer 2 · answered Aug 16 '15 at 07:13

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Without seeing the exact problem that you are running into I would suggest using

GDK_SCALE=x

or

GDK_DPI_SCALE=x

Before starting each application. You will likely have to manually change .desktop files or run from your shell prefixing the commands with GDK_SCALE=x

GDK_SCALE only allow interger values however GDK_DPI_SCALE=x allow for decimal values like i.e.GDK_DPI_SCALE=0.66

For other SDK based applications there are likely similar settings for respective kits. However since your problem is with gnome desktop I will provide this solution.

I haven't tried with a 4k monitor, but running GDK_DPI_SCALE=1.66 gnome-calculator will demo the solution.

Source: https://developer.gnome.org/gtk3/stable/gtk-x11.html

answered Aug 16 '15 at 07:13

Maeve Kennedy

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Thanks for the answer, but this does not work for the Xlib applications. – Ho1 Aug 16 '15 at 08:40
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Thank you for the answer, but this isn't really what I am looking for. I only encounter scaling issues with applications that don't use GTK3. I was hoping to find a solution that could be applied to any X application. – daxvena Aug 17 '15 at 04:26
https://wiki.archlinux.org/index.php/HiDPI has info that might be helpful for both GTK and non-GTK apps. I'd make an answer for it, but I don't want to transcribe the info over to an answer post. – Emmaly Jan 02 '17 at 03:55
How can we set the scale of an Electron app? – Aaron Franke Jul 08 '22 at 19:52

score 3 · Answer 3 · edited Apr 13 '17 at 12:37

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Vncdesk gives you a solution based on a local VNC client-server (see here)

It is not a complete solution for me because it gives some problems if the app need a window manager.

edited Apr 13 '17 at 12:37

Community

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answered Nov 23 '15 at 17:12

Sergio Llorente

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stevesliva · Answer 4 · 2018-03-19T19:58:26.733

I have an application that spawns many windows, and I cannot at the moment use xpra as is required by the accepted run_scaled solution. I also can't tolerate gnome-tweak-tool's 2x scaling. Too huge. Need 1.5x.

I have discovered that the tigerVNC java client supports client-side display scaling of 150%.

So I start a vncserver with 2/3rds size and a minimal windows manager:

vncserver -geometry 2520x1380 -xstartup ~/.vnc/xstartup-mwm

I then connect with TigerVNC's v1.7 java client (1.8.0 consistently crashes for me):

java -jar VncViewer-1.7.0.jar -ScalingFactor=150

Other than the commandline, you can hit F8 to get the VNC Viewer Options. Screen->Scaling Factor->150%. This scales the resolution from 2/3rds of 4k to 4k.

Archaic MWM in VNC with 150% scaling on the left. Fancy Gnome desktop (native) on the right, no scaling. You'll notice the tiny icons. Gnome is otherwise adjusted for 4k with 1.5x Font Scaling in gnome-tweak-tool, but the icons don't scale. This is just an example application -- the icons and scaling in the application that is pushing me this way are far worse.

Unfortunately this is an entire 1.5x scaled desktop with a separate window manager. It creates a nice walled-off area for my multiwindow app, but it's annoying to have a second window manager. Nonetheless VNC is something I'm familiar with from longtime use, and this does kick over to the laptop pretty easily, so perhaps this is usable.

VasyaNovikov · Answer 5 · 2022-02-07T20:30:17.417

I think I've found a GPU-accelerated solution! Install weston and run this:

weston --xwayland --scale=2
DISPLAY=:1 your_app

That's it!

Tuning

Note 1: You may have noticed a magical number has been used, DISPLAY=:1. The underlying assumption here was that your main xorg display is :0. If it's not, adjust accordingly.

Note 2: You may have noticed that weston has a top panel by default. You may want to remove it. To do that, create a weston.ini file:

[core]
idle-time=0

[shell]
panel-position=none
locking=false

And use it when starting weston weston --config=/path/to/weston.ini. You can also place it to ~/.config/weston.ini for it to be picked up by weston automatically, please refer to man weston.ini for further details.

EDIT: I've also documented the newly found approach here: https://wiki.archlinux.org/title/HiDPI#Unsupported_applications,_via_weston

Per-application window scaling in Xorg for high dpi display

5 Answers5

Tuning