[RFC] Multitouch proposal v2 + implementation

[Chase Douglas]

On Mon, 2010-09-20 at 10:29 -0700, Ping Cheng wrote:
> On Sun, Sep 19, 2010 at 9:45 PM, Daniel Stone <daniel at fooishbar.org> wrote:
> > Hi all,
> > This is my second draft of the multitouch proposal, along with a fairly
> > complete implementation; patchsets for inputproto, xserver,
> > xf86-input-evdev, libXi and xinput follow.
> >
> > This is more or less half way between Peter's proposal and my original
> > one: it doesn't use valuators anymore, but it has a different, and
> > hopefully more workable, approach to grabbing.
> 
> I have a corner case that I'd like to know how you address it.
> 
> How do we deal with the single touch case for multi-touch devices?
> Shouldn't we still post valuator for single touch events so MT devices
> can perform single touch functions while the touch is not grabbed by
> the client? The single touch use case can occur before and after the
> client grabs the MT events.

I don't think we can post single-touch emulated events while MT events
are grabbed because you'll get inconsistent handling by legacy X clients
and XI 2.1 aware clients. I think we'll need to hold single-touch events
until the MT events that define them are released.

-- Chase