I am trying XorgTablet (XorgTablet-18012013.apk, Galaxy Note 10.1, Android 4.0.4) + xf86-networktablet (Debian Wheezy, xserver-xorg 1.12.4) + Gimp 2.8.2. Status: No pressure sensitivity.
I put some debug prints into the xf86-networktablet code. I see the incomming events always having pressure set to 0. My primary suspect is the following repeated code in CanvasView.java in XorgTablet:
(int)event.getPressure(ptr)*PRESSURE_RESOLUTION
The (int) cast takes precedence over the multiplication. It casts the 0.0 to 1.0 pressure value to zero. The following multiplication does not matter. Zero pressure is sent from the android device to the desktop.
I do not have the build chain for Android, so I cannot confirm ahead of time that fixing this makes things work for me.