using touchpad as graphics tablet

[Peter Rayner <peter rayner lsce ipsl fr>]

This isn't quite gnome but it isn't quite blinux either,
apologies if you get this twice.

It's late and I have a crazy idea.  I need to look at a lot of
2-dimensional data.  Once, long ago, I wrote an application for this
for the Next using a mouse.  I had never bothered to inquire how mice
actually worked so was very surprised to find positions weren't
absolute (more enthusiasm than intelligence at work here) so the
application "worked" but didn't help.  and besides the hardware is long dead.  Now
I have this useless touchpad taking up space on my laptop.  I wonder
if I can't turn it into a cheap and nasty graphics tablet?  It would
need to take  pretty much complete control and return absolute
positions not relative movements etc but this sounds intriguingly
possible?  Anyone tried anything this silly or know of documentation
that might help?  gpm -r in graphics mode on the console looks
potentially useful although I'm sure it would be much nicer if this
played with gnome.  

The output side is easy, frequency for value and something giving
x,y,value or just value in response to a mouse-click or keypress.  I'm
happy to write such a thing but if someone wants a little project and
my eternal gratitude talk to me off line.
cheers
Peter


-- 
Peter Rayner: LSCE/IPSL, Laboratoire CEA-CNRS-UVSQ
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