[RFC] PDA as a TCP graphic tablet?

[Guennadi Liakhovetski]

Hi all

I have a device (Tuxscreen), capable of running Linux with a 
VGA-resolution (I think) LCD display with a touchscreen. So, I had an idea 
to use it as a graphic tablet. A quick google revield no existing 
software. So, I would just code a server on the device, that would get 
events from /dev/eventX, and send them over TCP to a PC, where a client 
would just export, say, a named pipe, which X would open as a device node. 
That's all nice and simple, now, I don't know how best to present this 
device to X. The touchscreen can deliver only x, y, and pressure. The 
device has a keyboard, so, I can switch between, say, those 3 modes that 
wacom tablets use (stylus, eraser, cursor)? Don't think many have 
Tuxscreens, but a possibility to use any Linux PDA as a graphic tablet 
(ok, pretty poor, but still) would be interesting to many?

So, what is the sensible way to bind to X? I would prefer not to have to 
write a new X-driver... Abusing the wacom driver would be dirty... I see a 
number of drivers in input/, but have no idea if one of them would be 
suitable for that. Don't think evdev would do? As an application I am 
thinking about Gimp.

If there is already a driver I could reasonable (ab)use, ideally it should 
only use read/write on the fd. If it uses ioctl's, well, that would mean I 
would have to write a kernel driver too. Not too dramatic, but not exactly 
the ideal solution.

Ideas?

Thanks
Guennadi
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Guennadi Liakhovetski