[Enhancement] HiDPI scaling on Linux with Gnome 3

[homocomputeris]

JabRef looks very different depending on resolution.
In QHD the elements are more or less reasonable (although the toolbar is hidden when the window is snapped #5499), the UHD version is just not usable because the buttons are smaller that the scaled mouse pointer.

2560×1440 QHD, 100% scale in Gnome 3:

3840×2160 UHD, 200% scale in Gnome 3:

JabRef 5.0.0-dev--2019-10-21----f86944aae
Linux 5.3.7-zen1-1-zen amd64 
Java 12.0.2

$ gnome-shell --version
GNOME Shell 3.34.1

[homocomputeris]

It is better scaled in Windows with 3840×2160:

[homocomputeris]

A GIF that compares relative size of the interface:
Linux 2.5K — Linux 4K — Windows 4K

[tobiasdiez]

You can change the (font) size in the preferences. This should then scale everything accordingly.

[homocomputeris]

Well, changing this value every time I connect to a screen is definitely not the thing I want to do.
Can't the factor be taken from the shell and applied automatically?

[tobiasdiez]

I don't see a way to automate this. Suppose the user has two monitor's with different resolution. How should JabRef know on which monitor it is displayed and which base value to choose for the font? Moreover, there are so many things that influence the effective size on the screen besides the resolution (dpi scaling e.g).

[homocomputeris]

To clarify: the scaling doesn't work properly even if only one screen is used. With 2-monitor setup it might be even worse.

Well, Gnome apps, Firefox, IntelliJ-based IDEs (written in Java) have no obvious troubles when they switch between HD and UHD.

I'm not really familiar with Java but the docs mention that OpenJFX can get the current screens DPI

[Siedlerchr]

You can adjust the hdpi scale using a command line switch:
#6086 (comment)