Touchpad gesture events via XInput2?

[Michael Weiser]

Hello,

I've been looking into the current state of affairs regarding touchpad
gestures such as swipe and pinch on Linux as an end user. Everybody
wanting to support them seems to be talking to libinput directly, either
necessitating the user having access to the input device nodes directly
(e.g. libinput-gestures) or talking to systemd's logind, becoming its
exclusive session controller and have it hand over open fds to those
(e.g. mutter [and only on wayland?]).

The former raises security concerns and the latter seems like a lot of
initial (logind) and followup (passing on events/access) work, quite
constraining (only one session controller) and DE(desktop
envionment)-specific to me (e.g. How does a KDE program see gestures
when running in a Gnome session where mutter is (maybe) passing them as
GTK signals?).

So I'm wondering: Are there any plans to deliver them as X events e.g.
via XInput2 or any reasons why that would be a bad idea[tm]?

I've done a bit of hacking of xf86-input-libinput, xorgproto, libxi and
xserver on a rainy afternoon and can now receive newly created swipe
XInput2 events - admittedly without any coordinates because I've yet to
understand the X server's valuator magic. Though it can obviously be
done I'm just wondering if it'd be worthwile spending any more thought
on.
-- 
Thanks,
Michael