Quote:
Originally Posted by axel77
Shall we sponsor a WACOM pen for you?  |
Haha, thanks - I have two. I only have one iLiad though, and since I can't use the stylus calibration data in my program, I wanted to get a feeling for how much inter-machine difference there is in stylus calibration.
That, and I was hoping to get a moral boost when people run the test app and discover that their iLiad is perfectly able to scribble pressure-sensitive sketches on. I'm rather stuck at the partial updates problem right now, so the project is in hibernate mode.
Anyway, you can grab the executable from
http://www.curly-brace.com/drawtest.
Before running it, you should find out what the pid of the Xfbdev server is, and send it a "kill -SIGSTOP". You can then run drawtest and scribble a bit with your pen. You will notice that I have to refresh the entire screen, which I throttle to once every few seconds. Exit for now is simply by typing ^C in the (ssh) terminal you ran it from, after which you can kill -SIGCONT the Xfbdev server again to get your system back (you may
need to flip a few pages in the content lister to force screen redraws). I hope you will notice some gray levels depending on the pressure you're scribbling with.
The story behind all this:
I don't like the quality of scribbles very much. Since they're not anti-aliased, they look much more "grainy" than the iLiad is capable of displaying. I wanted to experiment a bit with anti-aliased scribbles and perhaps one day write a full-blown graphics program for the iLiad, offering basic shapes and freehand drawing.
I quickly found out I can't use the normal X interface. The current software interface to the tablet doesn't provide pressure data. That means I need to read the raw packets from /dev/ttyS0. I therefore can't use the calibration data and will need my own calibration routine (current calibration is _very_ crude). Also, the X server can't be running at the same time as my app since we would be competing for input on /dev/ttyS0.
Hence the stop/restart action (which, obviously, would eventually be included in the application itself).
Another tough problem is partial updates. The official scribble app uses a special interface for this, in which they send custom commands to the driver. I asked on the iRexnet developer forum in an IM to Matthijs whether there is documentation for this, because obviously flashing the entire screen all the time is a definite showstopper. I haven't heard
back on this yet.