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:

[![Screenshot](https://i.stack.imgur.com/Af0Vr.jpg)](https://i.stack.imgur.com/Af0Vr.jpg)  

(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:

[![Screenshot](https://i.stack.imgur.com/fJVFL.jpg)](https://i.stack.imgur.com/fJVFL.jpg)

Answer: 
[Vncdesk](https://github.com/feklee/vncdesk "VNCdesk") gives you a solution based on a local VNC client-server (see [here](https://unix.stackexchange.com/questions/192493/how-to-use-xfig-on-high-dpi-screen))

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