Re: [Mactel-linux-users] appletouch zig-zags

[Ivan S. <iv...@al...>]

Ivan Stepaniuk wrote:
>    I have been using the appletouch driver for more than a year now,
> currently on linux 2.6.30. I noticed some time ago when trying to draw
> something on gimp, that when you move your finger the cursor response is
> not linear, but instead kind of "saw-tooth wave" shaped, across both X
> and Y. Of course it is more noticeable if your 'sensitivity' setting on
> X is high, but it is always there. Just to be clear, when you try to
> draw a diagonal line, for example a 45 deg line,  you end up with a
> zig-zag shape, no matter how straight you slide your finger.
>    I did not know anything about how the trackpad works until now, and I
> am not completely sure, but the number of 'jumps' of the response
> pattern seems to match the number of sensor elements for both X and Y,
> 10x20 in my case (05ac:021b Apple, Inc Internal Keyboard/Trackpad).
>    I tried on O$X it seems to work fine. I believe that there is
> something in the algorithm, perhaps in the atp_calculate_abs function,
> that is not totally correct, at least for this trackpad type.
>    Any suggestions or comments are welcome.
> Regards

Hi, no comments on this? I poked the source code without positive results.

-- 
Iván Stepaniuk
Alba Fotónica S.L.
www.albafotonica.com