#5961 HiDPI display not supported

[Alexey Kuznetsov]

Hello! Stendhall not running correctly on HiDPI diplays, text and menu are very small.

https://wiki.archlinux.org/index.php/HiDPI

[Hendrik Brummermann]

Hello Alexey,

that page says "Since Java 9 the GDK_SCALE environment variable is used to scale Swing applications accordingly. "

Which Java version are you using?

Does it work to set the scale factor manually as documented on that page?

[Alexey Kuznetsov]

I'm using Ubuntu and openjdk 11.0.5 2019-10-15, GDK_SCALE=2 works fine, but I expect java to set default.

[Anonymous]

I dig a little bit, to get current monitor scale is required to use dbus, simple python script shows how:

https://gitlab.com/Oschowa/gnome-randr/blob/master/gnome-randr.py

[Anonymous]

Here two solutions, first bash one, second using java dbus interface (linux only, windows and mac works fine). I reported this behaviour to openjdk, since it is only linux related issue, not sure if it ever be fixed, maybe it is a designed behaviour.

#!/bin/bash

HIDPI=$(dbus-send --session --print-reply --dest="org.gnome.Mutter.DisplayConfig" /org/gnome/Mutter/DisplayConfig org.gnome.Mutter.DisplayConfig.GetCurrentState | awk '/string +"legacy-ui-scaling-factor"/{while(1){getline line;if(match(line,/variant +int32 +([0-9]+)/,m)){print m[1]; break;}}}')

GDK_SCALE=$HIDPI javaws -headless https://stendhalgame.org/stendhal.jnlp

Using display library LinuxDisplay.getScale()

https://gitlab.com/axet/desktop/blob/dev/java/src/main/java/com/github/axet/desktop/os/linux/LinuxDisplay.java

[Anonymous]

I've check the code, something like this in stendhal Starter.java should solve HIDPI issue:

        import com.github.axet.desktop.linux.LinuxDisplay;

        if (System.getProperty("sun.java2d.uiScale") == null && System.getenv("GDK_SCALE") == null) {
            try {
                System.setProperty("sun.java2d.uiScale", LinuxDisplay.getScale());
            } catch (Exception ignore) {
            }
        }

[Anonymous]

"if" line suppose to be:

System.getProperty("sun.java2d.uiScale") == null && System.getenv("GDK_SCALE") == null && System.getProperty("os.name").equals("Linux")

[Anonymous]

Bug was accepted by Oracle: http://bugs.java.com/bugdatabase/view_bug.do?bug_id=JDK-8238077