[Development] Touchpad gestures on Wayland

[Povilas Kanapickas]

Hello,

I would like to implement support for Wayland touchpad gestures[1] to
Qt. Would you potentially accept such a contribution from an outside
developer if the CLAs are signed and other legal conditions are accepted?

Wayland currently provides swipe and pinch touchpad gestures which could
be represented by QPinchGesture and QSwipeGesture classes. It seems that
the gesture events could be handled just like they are handled on macOS,
but this needs a proof of concept to make sure the assumption holds.

If you agree that it makes sense for me to work on this feature, I will
come back with a more concrete proposal later.

Previously I've implemented touchpad gesture support in X11 and the X11
backend of Gtk so I know a little bit about this area. The code is
currently under review and once it's merged to X11 I'll come back with a
proposal for this part of Qt too.

Thanks a lot,
Povilas

[1]:
https://github.com/wayland-project/wayland-protocols/blob/master/unstable/pointer-gestures/pointer-gestures-unstable-v1.xml