Legacy Launcher supports HiDPI mode. You'll need:

• Legacy Launcher 1.123.0 or newer
• Windows, macOS with Java 11 or newer
• Linux with Java 11.0.12+ or 17+

UI scale works out of the box if you use Java 11 or newer.

Install latest Legacy Launcher (jar) and Java 11 (or newer).

Launcher is tested in GNOME 40 with GTKLookAndFeel on JDK 17 (Early Access) (11.0.12+ should work too)

Launcher may crash if you use e.g. 11.0.11.

If your JRE isn't picking up GNOME L&F settings and/or doesn't scale up the UI, then do the following:

1. Create arguments file (set variable TL_UI_SCALE to a number, e.g. 1.25 or 2)

$ TL_UI_SCALE=

$ [ -z "$TL_UI_SCALE" ] && echo "Don't just copy-paste. Please actually set TL_UI_SCALE" >&2 || cat <<EOF > tl.bootargs
-Dsun.java2d.uiScale=$TL_UI_SCALE
-Dswing.defaultlaf=com.sun.java.swing.plaf.gtk.GTKLookAndFeel
-Dswing.crossplatformlaf=com.sun.java.swing.plaf.gtk.GTKLookAndFeel
EOF

2. And start the launcher

$ java -cp LegacyLauncher.jar Debug
$ # or just:
$ java -jar LegacyLauncher.jar