Sample app scaling doesn't match OS scaling settings

[zugaldia]

This might go beyond the goal of these samples but, while I'm able to run them, I'm noticing that the scaling of the javaFX app doesn't match the OS:

Notice how the text in the Label' is smaller than the window title or the code in the background (IntelliJ)

This is running on Ubuntu 18.04 with 200% scale (Settings -> Devices -> Displays), JDK 11 downloaded from here and jmods downloaded from here. I wonder if this is an issue with my set up, or there's a missing flag/setting in the sample code that needs to be added.

[jperedadnr]

Have you tried same sample with JDK 9 or 10? See http://openjdk.java.net/jeps/263
Also have you tried running the sample with GTK2 or GTK3?

[zugaldia]

Thank you @jperedadnr for the quick and informative reply.

Also have you tried running the sample with GTK2 or GTK3?

I added applicationDefaultJvmArgs = ["-Djdk.gtk.verbose=true", "-Djdk.gtk.version=3"] to the build.gradle file to force GTK3 usage and enable some additional debugging. This is the output I'm seeing:

checking GTK version 3
trying GTK library libgtk-3.so.0
using GTK library version 3 set libgtk-3.so.0
Glass GTK library to load is glassgtk3
loaded gdk_x11_display_set_window_scale
loaded g_settings_schema_source_get_default
loaded g_settings_schema_source_lookup
loaded g_settings_schema_has_key
found schema 'org.gnome.desktop.interface' and key 'scaling-factor'
loaded g_settings_schema_unref

Unfortunately, that doesn't seem to have any effect on how the JavaFX app is rendered (content still looks about half the size it should).

Same thing if I try GTK2:

checking GTK version 2
trying GTK library libgtk-x11-2.0.so.0
using GTK library version 2 set libgtk-x11-2.0.so.0
Glass GTK library to load is glassgtk2
Gtk-Message: 12:09:24.343: Failed to load module "canberra-gtk-module"
loaded g_settings_schema_source_get_default
loaded g_settings_schema_source_lookup
loaded g_settings_schema_has_key
found schema 'org.gnome.desktop.interface' and key 'scaling-factor'
loaded g_settings_schema_unref

I've only tried this with JDK11 but from http://openjdk.java.net/jeps/263 it seems this should be working since JDK9?