Is there any simple/standard way to control the mouse pointer from userspace in Linux? As part of my final year project at uni, I'm developing a camera-driven gaze tracking interface that I'm hoping to demonstrate by using it to position the mouse pointer on the screen. With any luck (and permission from the department) it'll eventually be released under the GPL for accessibility applications, game control etc. Google is not my friend today. Any suggestions?

Just a thought (if you're going to go the X11 route) but you might be able to write a custom pointer driver and then load that as the X11 "mouse".

I'll only be needing support for X initially, yes.

The docs on writing drivers for X make it seem like quite a bit of work. Apparently, although you do have (wrapped) access to some standard lib calls, there are a lot of restrictions, which is the way it should be I suppose. Having discovered the joys of coding kernel modules a few months back, I'd really rather avoid more frustration with a similar system.

At the minute, I'm looking at using a daemon to run a named fifo with a standard mouse/touchscreen protocol and add it to the core events list that X watches for pointer input. Another fifo or other ipc interface would let my (GUI) vision/tracking system tell the daemon what to tell X. I think it should work pretty nicely (and with minimum coder stress!), but it seems a clumsy way to do it.

The reason for the daemon loop is that, as far as I can tell, my input system would have to be running when X starts up. This might be an assumption - my laptop uses the trackpoint and an external usb mouse. Until I started using udev, X would only pick up the usb mouse if it was plugged in before X started/restarted - if I plugged it in with X running, I'd have to restart X to get it working. Since the machine I'm testing my system on runs a 2.4 kernel, I assume that if I fire up my software and start talking to the input fifo after X has loaded, it will ignore the pointer input. Hopefully I can get around this by running the daemon to keep X interested while it starts up, then start my tracking software and feed the input to X through the daemon.

Am I right in thinking that X will ignore the fifo if it's dead on startup?

Also, finding good documentation for these protocols is proving difficult, since I'm not even sure which one I want to use. It needs abslute positioning, so I guess touchscreens are the thing to investigate...