multitouch events

Jordi Polo mumismo at
Wed May 14 18:26:03 BST 2008

I asked to the MPX developers in the Xorg list about the multitouch events
project and basically, they will like to make it toolkit agnostic, so the
same gestures can be seen from every application ( the meaning of the
gestures will be application specific, but at least a 3 fingers U shaped
gesture will be a 3 fingers U shaped gesture for everyone).
So I have this proposal, let me know if it is acceptable / looks good for

First, the library will only deal with X multitouch blobevents. mouse events
is a different problem and will be solved or it is already solved by
different projects.
Second, As in multitouch blobevents we have plenty of room for gestures (1,
2, 3, 4 finger gestures, etc). Blobevents read from X can be split in 2
types: "immediate" and "gesture".
Immediate events will be multitouch versions of ONE pointer events (mouse
moves, etc).  These events will be immediately sent to upper layers
(toolkits, etc). Or maybe better, mouse events will be sent instead so apps
doesn't even realize.
Gestures events will be everything else, will be eaten by the library and
never sent to upper layers. Only the distiled version (gesture event) will
be sent.
This division is what make it feasible to make the library toolkit
independent, having the "immediate" events outside the control of toolkits'
event loop (and mangling with them) looks too scary.
Third, the library will have a DBUS configuration interface.
I guess that some special applications (3D modeling ...) will want to
explote blob events themselves. The library can be deactivated.

I think I can build a touchlib/reactlib etc based cheap multitouch screen,
that will give TUIO me events, bridge them to blobevents and work from there
upwards. In the meantime hopefully MPX enters Xorg and the work on
multitouch events is resumed.

On Sat, May 10, 2008 at 6:27 PM, Jordi Polo <mumismo at> wrote:

> On Sat, May 10, 2008 at 4:20 PM, Brad Hards <bradh at> wrote:
>> On Saturday 10 May 2008 04:38:42 pm Percy Camilo TriveƱo Aucahuasi wrote:
>> > >There you go:
>> > >
>> >
>> > I remenber that some time ago saw some video/demo of MPX. I think that
>> this
>> > tecnology is similar to microsoft surface. It would be really great that
>> > KDE had this feature.
>> This is why you should have come to!
>> See for the plan, and
>> for the slides.
> Basically, it is a 2 years old (stable and proven) implementation of all
> the low level technologies I would need.
> Thanks a lot for the links.
> This will make the whole thing MUCH more easier to implement.
> Then, a good general plan can be:
> - Create QBlobEvent/KBlobEvent from X blobevents
> - Create a library that taking Q/KBlobEvent generate KGestureEvent
> - Send all the new events to the applications.
> - Modify KActions to make them use KGestureEvents
> Anyway, it seems that so far the blob events is not in the X server, will
> not immediately enter official X repository. So I will start playing with
> libtouch/MPX server instead.
> I'll try to go to the LinuxConf next year... :P
> --
> Jordi Polo Carres
> NLP laboratory - NAIST

Jordi Polo Carres
NLP laboratory - NAIST
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <>

More information about the kde-core-devel mailing list