Touch events

Daniel Stone daniel at
Thu Feb 23 16:04:55 PST 2012


On 23 February 2012 20:22, Bill Spitzak <spitzak at> wrote:
> Chase Douglas wrote:
>> The client won't see the third finger if it touches outside its window.
>> In the wayland case, only the WM has all the info needed to determine if
>> a touch is part of a global gesture. The WM needs to make the decision,
>> not the client.
> I'm pretty certain all touch events *MUST* go to the same surface until all
> touches are released. Otherwise it will be quite impossible to do gestures
> reliably, like the user could not do them to objects near the edge of a
> window.

On touchpads, yes.  On touchscreens, no.

>> That would be bad UI design because then global gestures would fire only
>> sometimes. Further, it would break global gestures if touches occur over
>> a broken application.
> I consider it bad design that global actions are "complex" (like needing 3
> fingers) or global shortcuts require lots of shift keys held down, just to
> avoid collisions with applications.

Needing three fingers isn't complex.  My grandparents can understand
it, and regularly use three-finger gestures.

>> I think we can look at other OSes as case studies. iOS and OS X employ
>> effective global gestures imo, and they take precedence over the
>> application receiving touch or gesture events.
> I think it is pretty clear that "what other OS's do" is not always what
> Wayland wants to do. Most of them copied ideas from X.

Not really.  X's input system is pretty unique (and pretty uniquely
broken), and I think it's safe to say that no-one -- least of all iOS
-- has copied it.


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