I had the same symptoms. Try the changes to the code I made in pull request 95. It uses a newer Linux API to register the device, and libinput seems happy with it now, so it works in gimp and inkscape.
Screen to tablet
the whole thing is working fine on arch-linux using gnome shell!
Would it be possible to have a picture of the screen on the Android device?
Maybe it doesn’t need to be a live-view. Only a screenshot for orientation could be a very nice feature to draw on.
We’ll try to incorporate something like that in the future! Thank you for the suggestion