RFC: multitouch support v2

[Alex Elsayed]

Kristian Høgsberg <krh at ...> writes:
> Right... in the MPX sense, right?  So you could have a keyboard and
> mouse combo controlling one pointer/kb focus and the touch screen
> being its own master device.  Then maybe you could have one person
> using the touch screen UI, and another person using the kb/mouse
> combo.  That's kind of far fetched, of course, but I think the main
> point is that there's no inherent association between a kb/mouse combo
> and a touch screen.  On the other hand, what about a setup with two
> mouse/kb combos (master devices) and a touch screen... you'd expect
> tapping a window on the touch screen to set kb focus, but if you have
> multiple master kbs, which kb focus do you set?  Maybe we're just
> doomed for trying to make both pointer and direct touch interaction
> work in the same UI.

One use case you seem to be forgetting is that there are mouse-type
devices like recent Synaptics touchpads that *also* do multitouch.
Multitouch != touchscreen. One way to solve this might be to make 
touchscreens a pointer device *with no associated keyboard device*,
or at least none attached to actual hardware. In XInput, you can create
a new master pair with a real pointer, but only an XTest keyboard. A 
dummy, if you will.