Adding this issue + solution to contribute to the wiki...
On Pi 4, the xcompmgr daemon must be running in the background for transparency to work. It can be enabled in raspi-config, but that does NOT work as it starts the daemon using 'xcompmgr -aR'. Those flags seem to prevent the transparency from working in the Java/VLCJ combo.
Disable compositor in raspi-config and then run it before starting the Java program. It can be put in a startup file (Google it), but I just invoke it in my bash script which starts the Java program (after removing any existing process):
killall xcompmgr
nohup xcompmgr &
On the Pi 5, there is a compositor already running by default and transparency works fine.
I am also running Java 22 and so far everything works fine.
caprica
commented
3 months ago
Adding this issue + solution to contribute to the wiki...
On Pi 4, the xcompmgr daemon must be running in the background for transparency to work. It can be enabled in raspi-config, but that does NOT work as it starts the daemon using 'xcompmgr -aR'. Those flags seem to prevent the transparency from working in the Java/VLCJ combo.
Disable compositor in raspi-config and then run it before starting the Java program. It can be put in a startup file (Google it), but I just invoke it in my bash script which starts the Java program (after removing any existing process):
killall xcompmgr nohup xcompmgr &
On the Pi 5, there is a compositor already running by default and transparency works fine.
I am also running Java 22 and so far everything works fine.