X Gesture Extension protocol - draft proposal v1

[Simon Thum]

Am 16.08.2010 21:41, schrieb Chase Douglas:
>> What's the reasoning behind this architecture?  Could the gesture
>> recognition just be done in the client, provided we have a good way
>> for X to communicate multi-touch events?  Splitting it up into a
>> "gesture engine" and teaching X about gestures seem unecessarily
>> complex at a first glance.
> 
> I go into this in depth in section 3. In brief, all this is needed
> because gestures are fundamentally groupings of touches that convey a
> meaning together. With just multitouch X, touches occurring inside
> different windows that select for events will be sent to the windows
> respectively, depriving us of the ability to recognize them as a group
> with one meaning. Thus, a different form of propagation is needed,
> separate from how X Input propagation is performed.
> 
> Also, we think that there's a case to be made for environmental gestures
> that should override gestures recognized by clients. This is provided by
> the mutual exclusion flag when selecting for events. Again, this
> wouldn't be possible without integrating it into the X propagation
> mechanism.
I like it, if only because it resembles what I described on the list
earlier that year :) The protocol's probably tricky to get race-free,
but surely worth it. I'll have a more thorough look at it this week.

I'm cc'ing florian in case he's still working on the issue.

Cheers,

Simon