Playing with touch screen events
andy at openmoko.com
Mon Oct 20 14:51:53 CEST 2008
-----BEGIN PGP SIGNED MESSAGE-----
Somebody in the thread at some point said:
| On Mon, 20 Oct 2008 18:00:36 +0800 Tick Chen <tick at openmoko.com> babbled:
| yup. most of these i have observed just in doing the ui stuff. drags are
| basically unreliabel as u get discontinuous events (down, move, move,
| down, move, up, down, move, move, move, up) etc. if you press very
| reliable. and the offcenter press is another problem. you would
| press is in the middle of your finger, but its actually just at the very
| top/bottom or just off it above/below.
| what we need is a better touchscreen.. or a very very good filter
between the ts
| device and x events so every app gets reliable events. tslib i think
| an infrastructure - BUT i never got time to play with it. :)
I think these behaviours can also be trouble in the driver... "pen up
and down" is a separate interrupt than sample from ADC and it wouldn't
surprise me if we can improve it. There was a patch about it from Dima
| nb - kinetic scrolling. inside e it actually collects a whole series
| (the 20 most recent mouse events) and computes motion over all of them
Actual position averaging is pretty solved by the "median" patch stuff,
there's some question about whether it's acceptable upstream I guess we
are going to have to find out about.
|> I wrote a small application to observe the touch screen events.
|> And found some very interesting phenomenons.
|> 1. If the touch pressure is very light, the status of mouse will
|> becomes very unstable. Mistake move events as up and down events.
You did a good thing studying this Tick.
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.9 (GNU/Linux)
Comment: Using GnuPG with Fedora - http://enigmail.mozdev.org
-----END PGP SIGNATURE-----
More information about the devel