Multi-Touch

mathew davis someoneinjapan at gmail.com
Tue Apr 3 16:46:00 CEST 2007

```Hello everyone I would just like to start off by saying I have enjoyed very
much the conversations that go on inside this mailing list.  I have learned
a lot more by trying to research answers and solve problems then I ever
thought I would.  With that being said I have been thinking about
multi-touch lately and after some things on the wiki page
http://wiki.openmoko.org/wiki/UI_Improvements I noticed that is mentioned
the zoom feature of the iphone.  it stated that

Question:

What exactly does the touchscreen see when  you touch the screen with
2 fingers at the same time,
when you move them, when you move only one of the 2, etc. I'm also
interested in knowing how precise
the touchscreen is (ex: refresh rate, possible pressure indication, ...)?

- The output is the center of the bounding box of the touched area
- The touch point skips instantly on double touch
- Pressure has almost no effect on a single touch, but not so on a
double touch. The relative pressures will cause a significant skewing effect
towards the harder touch. You can easily move the pointer along the line
between your two fingers by changing the relative pressure.

So my question now is do we have access to the bounding box?  If we can get
at the coordinates of the bounding box can we not figure out if the bounding
box is shrinking or growing?  The iphone has a camera which makes the zoom
feature more attractive as you can zoom in on pictures you have taken with
the phone.  But with the better screen resolution on the neo I would still
like to be able to manipulate pictures I have on my neo.  Also if we have
access to the bounding box we could with some practice figure out when users
are trying to rotate an image.  This could also be very useful with web
browsing.  With the iphone you can view the entire website as if on a normal
computer then zoom in of places you want to read.  I think this would be a
great feature on the neo.  I wouldn't have the first clue how difficult that
would really be as I am sure it would be quite encompassing but with the
high resolution of the neo this should help a great deal.  And even if we
couldn't get multi touch working a zoom feature in the browser would still
be helpful.  You press the zoom button then click an area to enlarge.  Just
curious how difficult would this be?  Any way I have just been kind of
looking at the iphone and it doesn't seem to be very multi touch but as it
has not come out I could be wrong.  It seems to only be able to accept 2
two fingers touch the touch screen the I believe we could simulate
multi-touch.  I don't know how responsive this would be to the user either
maybe someone could answer that?  So I am just curious if this is possible
in some degree or not?

Thanks,
Matt
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