Multitouch followup: gesture recognition?
floe at butterbrot.org
Sun Mar 21 02:37:27 PDT 2010
[ I just came across the multitouch discussion thread from last week.
I'm starting a new thread, as what I'm thinking about is only indirectly
related to the old one. ]
I've briefly seen "x gesture library" mentioned in that context. As one
core topic of my PhD thesis (, see chapter 3) was a generic gesture
recognition engine, I'm very much interested in this aspect.
I'd like to give a very brief outline of the concepts I've developed
during my thesis (for an implementation and some more details, please
- The core elements of the entire concept are /features/. Every feature
is a single atomic property of the raw input data, such as "motion
vector" or "number of points" or "relative rotation angle" etc.
- One or more features, together with optional boundary values, compose
a /gesture event/. When all features match their respective boundary
values, the event is triggered.
- Gesture events are attached to /regions/, which are more or less like
XWindows with the important difference that they can have arbitrary
shape (polygons). This is needed because input event capture
happens /before/ the interpretation into gesture events, therefore
common event bubbling would be quite difficult.
As I said, this was just a very brief outline. These concepts are proven
to work and allow for stuff such as on-the-fly reconfiguration of
gestures or portabiltity across widely different input devices.
Now, in an Xorg context, I'd very much like to hear your opinions on
these concepts. Would it make sense to build this into an X helper
Many thanks for your opinions!
0666 - Filemode of the Beast
More information about the xorg-devel