Re: multitouch on N900
 

For multi touch you will need multi point support. X did not have multi point support for a long time, although it was in development for a long time, called MPX.

Since summer 2009 MPX is included in X Server 1.7.x. I don't know if this requires additional porting to ARMEL or Maemo and if so how straightforward this porting will be. Multi touch is also not the same as multi touch, but multi point is quite complex to implement, and that part is now ready.

However, rest assured the X Server shipped with Maemo 5 does not support MPX.

See also http://talk.maemo.org/showthread.php?t=33176 you can see some demos here as well although they use a mouse cursor; not multi touch.

Re: multitouch on N900
 

I've tried this with both my tablet PC (Paint on my OQO with a Wacom digitizer running Win7) and N810 (Xournal in drawing mode). Both screens demonstrate two recognitions.

If both pens are moved close to (in the Wacom's case) or on to the screen in approximately the same time, the software averages the two locations and puts the cursor there. If one is lifted the cursor immediately shifts to the remaining position.

If the pens are sensed one after the other, the cursor begins at the first and moves to the second. For touch screens, this is the essence of the vectoring problem in Windows handwriting recognition.

You would have to have the software define the minimum separation of registered points and the speed between registrations and their associated points to attempt to define multiple touches versus one big touch or a rapid movement of a single touch. It would also have to group all registered points into sets of touches to handle fingers rather than pens.

It wouldn't be trivial to program this nor would it be trivial for a system to run it and respond in real time. I suspect that while it could theoretically be done, it is more of a university research project than a usable system enhancement.

Re: multitouch on N900
 

Fine, but I think you missed the point a bit. He's talking about emulating multi-touch by checking for the position of a single touch moving at a rapid speed, if I understand correctly.

Re: multitouch on N900
 

@allnameswereout
Thanks for the post, it is always good to get the terminology straight :)
However, I'm not pointing into real multi-point, as the hardware (resistive screen) does not support this.

@DaveP1
I'm playing with Sketch on my N810 at the moment:
you put one finger, then you put another. now you move your second finger.
I believe it should be totally doable to recognize this effect with software.

I appreciate your technical suggestions.
What are your thoughts about usability of this pseudo multi-point (zoom in/out, rotate) in Maemo, provided it works fairly well?

Re: multitouch on N900
 

Hi guys

Felt I had to register and join the talks while I wait for my N900, along with the rest of you ;)

A brilliant guy, name Jamie Fuller has apparently made a proof-of-concept rythme game for the Nokia 5800 which (as far as i know) also has a resistive screen.
http://www.youtube.com/watch?v=XndW7YlvYjU

Re: multitouch on N900
 

I think, that this is not a good solution, because I believe, that it would not work very good.
But did you remember the 1 1/2 touch to zoom from the picsel viewer from palmos?
tap - lift - tap and hold - stroke down to zoom in, stroke up to zoom out.

Re: multitouch on N900
 

Yes, this is exactly what I have in mind (the technical side I mean). This is not a real multi touch/point, if he was pressing screen in one point exactly in the middle, he would have the same effect (both buttons would lit).

Incorporating moves would be a bit more difficult, but still possible (IMHO)

Re: multitouch on N900
 

Hi, Welcome to the forum :)

Re: multitouch on N900
 

Ah yes, didn't realize.

We call that 'gestures'. One application using them for long long time is Opera. Albeit mouse gestures.

One side effect of this emulation may be the kernel driver must then check very often for the input which will use considerably more battery juice. Although the display driver won't have to show that it checks more often; only touchscreen/input part needs to.

Re: multitouch on N900
 

I would suggest that this is a dead end. I just don't see it as reliable enough to be usable. It is much more likely to be frustrating. OTOH, I think that gesture recognition could be used. This is, essentially, an enhanced version of swipes. Take a look at StrokeIt. Who knows, it might even be portable to Maemo.

http://www.tcbmi.com/strokeit/