multitouch events

Jordi Polo mumismo at
Tue May 6 14:28:22 BST 2008

I was wrong saying that there exist an X server implementation with
multitouch, what there exist is a multi-pointer, multi-keyboard Xserver.

On Tue, May 6, 2008 at 4:18 PM, Jordi Polo <mumismo at> wrote:

> Hi,
> I have the chance to get involve in some Human interface projects but want
> to make then as general as possible.
> == WHY ==
> First there exist a library that let create cheap multi touch panels (
>, they use computer vision, so a
> lot of computing is needed and some tuning. Alternatively there are some
> multitouch, multifinger support for the Wiimote (
> These projects use specialized libraries and are quite geek/research like.
> On the other hand, we have the new Mac Air /Mac book pro with their basic
> multitouch gestures support.
> And the thing that made think about all this:
> Even the above article is about a patent and it doesn't mean it will
> materialize in a product, I'd say that the next Mac whatever laptops will
> come with a bigger trackpad with extended gestures support.
> If they don't, with cheap (only one wiimote is needed) multitouch displays
> available, it can be really cool if Linux/KDE leads the way on interfaces
> innovation.
> I think the above Apple's ideas are pretty clever, use multitouch to
> define usual GUI operations like copy or paste. Meaning no revolution is
> needed on the UI and applications should not be wildly reworked. Also means
> that multitouch hardware can be little by little more common place till the
> point that we can change the UI to be more specifically multitouch (the zoom
> idea is the first obvious thing).
> I hope you agree with me in the convenience of multitouch support. I guess
> this can be easily flamed as not everyone will like the multitouch paradigm,
> also  accesibility concerns can easily argued. That's why it should be done
> gradually, trying to make it configurable, etc.  I hope that it can be seen
> at least as interesting to be explored.
> == HOW ==
> As I said, today multitouch programs are done with multitouch specific
> libraries and tent to be fancy 3D stuff. I will like to include the
> multitouch support in KDE in a way it can be easily used by normal
> applications. In fact the support should not be limited to KDE.
> Current Xorg has no multitouch support. It does exist a X implementation
> that supports it and I read somewhere that someone was working on multitouch
> Xorg but not sure about progress.
> From my point of view, the perfect implementation would be a low level
> library/ Xorg taking care of creating basic events from the multitouch
> hardware (much like mouse or keyboard).
> Those will be converted to new types of QEvents, maybe Trolltech is even
> thinking about adding multitouch support in 4.5 for Mac platform (very wild
> guess).
> Since this point I am not sure what should be the best implementation.
> In my ignorance of KDE internals I would suggest adding multitouch
> handling to KActions, so the applications will not need to be changed. To
> put an example, KMyWhateverApp will add a KAction copy action that is
> activated with Ctrl+c and with the gesture two_fingers_up.
> Gestures to show Plasma dashboard, launch krunner, etc can be managed as
> current global shortcuts are managed.
> Applications will of course receive multitouch QEvents (those not filtered
> by KActions I guess), modifying the apps to use the events in fancier ways
> is a problem of every app developers.
> As I said I want to make the whole multitouch stuff useful for OSS in
> general instead of the "make a cool looking project" that I have being
> offered. So for me the important point is if this kind of work is really
> seen as useful and integrable in KDE or no. I am sorry for the hand waving
> but I will not even start the project if it is not going to help a bigger
> audience than my 2 reseach fellows...  So:
> ¿What problems do you see to the general high level implementation ideas
> above?
> ¿Do these ideas have a place in KDE?
> ¿If multitouch hardware is not massively available (let's say some macs
> and maniac wiimote users only) it has the chance to be added to KDE?
> ¿If the only way to get multitouch information is a non- Xorg related
> library, it is implementable?
> ¿If that library is not widely deploiyed, it is ok to include code in
> kdelibs that use it?
> --
> Jordi Polo Carres
> NLP laboratory - NAIST

Jordi Polo Carres
NLP laboratory - NAIST
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