# Is there a way to drive the display via HDMI from a systemd service

When my Raspberry PI starts it will start a process using systemd. At this point the display of the PI will be the standard PIXEL desktop. This process does not run as root.

What I am looking for is a way to display something full screen over the top of the desktop from the systemd process. The idea being this process will receive data over the network and then display various things on the screen to the user.

I've read a about a few technologies but not sure how they fit together.

The first I saw was FrameBuffers which looks like a way to write data to the screen but I am not sure if this is just to the current terminal or full screen over the desktop.

The other mechanism I saw was writing to the GPU which directly outputs to the HDMI port. The examples I saw here we using assembly language but my code would be written in python.

I would appreciate some pointers on if what I want to do is possible otherwise I will need to find another solution.