JavaFX / Wayland Test

This is a simple JavaFX app for debugging touch scrolling/dragging issues on X11 vs Wayland images.

System Setup

The Variscite DART-MX8M-PLUS kit was used for development and testing, using Yocto images with targets core-image-x11 and core-image-weston.

Environment Setup

OpenJDK

JDK 21 (Linux/AArch64) can be downloaded here

Extract the JDK to /usr/lib/jvm:

tar xvzf openjdk-21.0.1_linux-aarch64_bin.tar.gz -C /usr/lib/jvm/

OpenJFX

JavaFX 21 can be downloaded here

Extract to /usr/share/java/

unzip -d /usr/share/java/ openjfx-21_linux-aarch64_bin-sdk.zip 

Building the App

From the top of the project directory, set JAVA_HOME to the JDK location above and build with gradle:

export JAVA_HOME=/usr/lib/jvm/jdk-21.0.1/

./gradlew build

Running the App

If running the app via SSH, remember to set the display environment variables

export DISPLAY=:0

And if on Wayland:

export WAYLAND_DISPLAY=wayland-0

Additionally, if running as root on wayland, you'll need to grant the root user access to the display. From the weston user, run:

xhost si:localuser:root

Then, run the app from the top of the project directory:

/usr/lib/jvm/jdk-21.0.1/bin/java -Djava.library.path=/usr/lib/ -cp "build/libs/app.jar:build/libs/*" \
--module-path /usr/share/java/javafx-sdk-21/lib \
--add-modules=javafx.controls,javafx.fxml,javafx.base,javafx.graphics \
--add-exports javafx.controls/com.sun.javafx.scene.control.behavior=ALL-UNNAMED \
--add-exports javafx.graphics/com.sun.javafx.scene.traversal=ALL-UNNAMED \
--add-exports javafx.graphics/com.sun.javafx.scene=ALL-UNNAMED \
--add-exports javafx.controls/com.sun.javafx.scene.control.skin=ALL-UNNAMED \
--add-exports javafx.controls/com.sun.javafx.scene.control=ALL-UNNAMED \
--add-exports javafx.graphics/com.sun.javafx.util=ALL-UNNAMED \
-D com.sealingtech.snts.waylandtest.HelloApplication

The Problem

On the X11 based image, the application behaves as expected. The user can scroll the list of labels by dragging their finger on the touch screen. However, on the Weston/Wayland image, dragging to scroll does not work. The view shifts slightly but immediately stops scrolling. On the X11 image, the MouseEvent.MOUSE_DRAGGED event is fired repeatedly while the user moves their finger on the screen. On the Weston/Wayland image the MOUSE_DRAGGED event is immediately followed by the MOUSE_RELEASED event, event though the user is still touching the screen.