[RFC] PDA as a TCP graphic tablet?

[Glynn Clements]

Guennadi Liakhovetski wrote:

> 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.

Have the server-side client use a pty, which X should be able to use
in the same way as a physical serial port.

-- 
Glynn Clements <glynn at gclements.plus.com>