Too Tiny images and text on linux with high DPI monitor

[xyzzy57]

I am running Kubuntu 25.10, which uses Wayland rather than X11.

I have very high resolution monitors.

One is running at 3840 x 2160, with a scaling factor of 170%
The other is running at 3840 x 2160, with a scaling factor of 165%.

Yes, fractional scaling. Most linux systems can do this, and wayland does it beautifully.

Except for certain apps, particularly those written in java.

One of them is the Haven client. I've tried default, ender, and hurricane. All images and text that are small enough I'm practically pressing my nose to the screen to read them, and soon develop a headache.

The *same* monitors produce excellent results running Haven when attached to a MacMini running MacOS 15.5, but the mac is running them both at 1920 x 1080, with no scaling factor. From what I've read, MacOS can do scaling on its own "Retina" monitors", but maybe not with equivalent monitors not sold through Apple.

I've tried every remedy I've found on Google, with no joy.

Interestingly, the hurricane client now comes with a Play_Linux.sh that sets several of the java arguments mentioned in my google research. But that didn't solve my problem of everything I see in the client being too small for my aging eyes. In fact, its behaviour on my linux system is the same as that of the default client.

Hurricane uses
-Dsun.java2d.uiScale.enabled=false \
-Dsun.java2d.win.uiScaleX=1.0 \
-Dsun.java2d.win.uiScaleY=1.0 \

This looks to me like an attempt to turn off any scaling used in the rest of the system.

I get the same results when I launch haven (default client) from Steam. I also get similar behaviour when running Civilization V (from Steam), but the steam client itself is fine. I haven't tried other steam games on this linux system yet.

I *suspect* the issue is the use of fractional scaling (165% and similar), but it might just be an allergy to some other aspect of linux or its display handling.

[azrid]

Did you try turning up the interface scale in the game options?

[blueday]

First, completely talking out my ass, so keep that in mind.
I am guessing most apps you are referring to are using KDE/X11/Wayland apis to draw their interface. These get parsed with scaling in mind. Civ/HH/etc. are probably going a little lower level, so they are seeing the native 4k resolution. I would suspect this allows better direct access to the graphics hardware, but suffers from scaling not being accounted for. As azrid said, using the built in UI scaling is likely the answer.
Avid linux user, but never used scaling, so again, completely making this up as I go.

Edit: Wife uses windows with scaling, but her games still default to native res and are sized appropriately. Seems like native res trumps all.