Look at drivers, not applications
You won't find a program doing this, because of these three types of touchpads the drivers tries to abstract to a single representation to applications:
- Touchpads reporting absolute positions data is being translated by the Xorg driver to relative movement for the applications. A regular application can't talk to the touchpad directly (by design), so you really have to look for a solution in the driver.
- Touchpads capable of both relative and absolute modes needs switching of modes, which is very hardware specific and not application-aware.
- Some more basic touchpads don't have the capability of reporting the absolute positions.
Unfortunately, even if you have a touchpad pretty much capable of reporting all absolute values, most touchpad drivers do not let you use them in Linux applications. The absolute data is really there, as the driver can detect whether you are touching it at the edges for scrolling for example. Test this for yourself using evtest in a virtual terminal (to suspend X). My Synaptics touchpad reports the absolute positions as follows:
Event type 3 (EV_ABS)
Event code 0 (ABS_X)
Value 3332
Min 1472
Max 5648
Fuzz 8
Resolution 39
Event code 1 (ABS_Y)
Value 2017
Min 1408
Max 4806
Fuzz 8
Resolution 79
The capability of actually putting a Synaptics device in absolute mode in Xorg has been removed recently by this commit in the xf86-input-synaptics driver:
Remove absolute mode
Moving a touchpad in absolute mode is unusual - touchpads are disconnected
from the output device, so direct interaction is hard. There appears to be
little usage of it (I haven't seen bug reports from people claiming to use
it). Joe Shaw, author of the code and only known user doesn't have a use for
it anymore, so purge it from the repo.
System wide basic driver: evdev
The only way I see this to be possible at this moment in Linux is using the evdev driver in Xorg. It was discussed back in 2010 on the Xorg mailing list (an excerpt below):
I have to get the absolute
position of a finger on the touchpad rather than just relative
movement.
the synaptics driver doesn't do this, but the evdev driver does. So
you need to configure your X server to use the evdev driver for the
touchpad instead. The following configuration snippet will do that for
you provided you're running server 1.8 or later.
Section "InputClass"
Identifier "evdev touchpad"
MatchIsTouchpad "on"
Driver "evdev"
Option "Mode" "absolute"
EndSection
Save this as /etc/X11/xorg.conf.d/99-evdev-touchpad.conf and restart
the server. Note that this only changes the behaviour of the touchpad
itself, not the data in the events but then again that data is always
absolute anyway. Also, by using evdev instead of synaptics you're
losing the ability for two-finger scrolling, tapping, etc.
Bottom line: create a feature request
I see room for a feature request on the upstream bugtracker for the synaptics driver (and possibly others). It would be very much useful to have an interface in Xorg to be able to read the absolute position values of the touchpad. The main blockers I see is that this might be very much hardware specific and therefore hard to implement.
I think talking to Joe Shaw and Peter Hutterer could also be of great value to see what the history in this is exactly, how to make it a great feature request and what to expect from it.
