Different display scale settings - 18.04
Solution 1:
On Gnome 3.32 (default for Ubuntu 19.04) is possible to set up fractional scaling even for X. The command is:
gsettings set org.gnome.mutter experimental-features "['x11-randr-fractional-scaling']"
After that you can go to Display Settings and sets different scaling ratio for each monitor you have, even in 25% increments.
If, for any reason, you need to reset fractional scaling, the command is:
gsettings reset org.gnome.mutter experimental-features
Solution 2:
There is an easy workaround.
Instead of changing the scale: change the resolution of the monitor.
With a lower resolution on a 4K screen, you should be able to match the additional monitor.
Hope this helps.
Solution 3:
Lower the resolution of monitor could solve the problem, but that's not a good solution because it sacrifice the 4k resolution.
Assume you are using x-window and ubuntu 18.04. A better but more sophisticated approach is: keep resolution of monitor to 4k, raise your laptop monitor resolution double and scale up all windows 200%. Detail step as follows:
- Go to setting > displays > set scale to 200%
- Connect to dell monitor, type xrandr to check for id of two monitors. Here I assume you have monitor 'HDMI-0' of 3840x2160, monitor 'HDMI-1' of 1600x900. Now I want to place 'HDMI-1' to left, 'HDMI-0' to right.
- Run the following
xrandr --dpi 276 --fb 7040x2160 --output HDMI-0 --mode 3840x2160 --pos 3200x0 --output HDMI-1 --scale 2x2 --panning 3200x1800+0+0
(Note: 7040 = 3840+1600x2, 3200=1600x2, 1800=900x2)