Are all trackpads capable of running in absolute mode?

Question

I'm interested in using the trackpad on my laptop as a small graphics tablet, somewhat like Inklet for OSX. I'm running Ubuntu 12.10 on my laptop. I asked about similar software on askubuntu.com, and the question was asked whether all trackpads are capable of running in absolute mode. My intuition says that trackpad hardware must work with absolute coordinates, and that these are translated to relative coordinates by the driver, but I don't have any way of backing this up. Based on web forums and Synaptics TouchPad documentation. It looks like this is definitely true for some devices, but I would like to point to something more definitive.

Do all trackpads work natively in absolute mode? Are they all capable of running in absolute mode?

Answer 1

Apparently, the answer is no to both questions; there are trackpads which only report relative positions.

See http://stackoverflow.com/questions/3470935/how-to-read-absolute-positions-of-tap-from-cirque-touchpad-in-linux

As well as gertvdijk's comment in http://askubuntu.com/questions/239823/use-laptop-trackpad-as-graphics-tablet#comment301432_239823