See the test script https://bitbucket.org/techtonik/discovery/src/tip/graphics/gfxtablet/?at=default
X,y max seems to be about 32000, not 65535 as described
What about the pressure value? I can’t relate it to the values in GIMP’s input device settings.
The raw values seem to go from ~1200 (min) to ~4800 (max).
And in GIMP it looks like it’s divided by 10, but not really.
Which makes it really hard to find the right curve to get 100% opacity when pressing on the screen as hard as possible.
What about the pressure value?
Android: »A normalized value that describes the pressure applied to the device by a finger or other tool. The pressure generally ranges from 0 (no pressure at all) to 1 (normal pressure), although values higher than 1 may be generated depending on the calibration of the input device.« [https://developer.android.com/reference/android/view/MotionEvent.PointerCoords.html#pressure]
The GfxTablet app maps [0…2] to [0…65535] so that 32768 means 1.0 in Android pressure.
The uevent driver sets 0 and 32768 as the min/max values, so that an original Android value of 1.0 corresponds to the max value of the uevent pressure.