Libinput Patches Add Three-Finger Pinch

The latest feature work on Libinput is for supporting three and four finger pinch gestures.

Peter Hutterer posted the fourteen patches today for adding three and four finger pinch gesture recognition to this input handling library used by Wayland compositors, optionally via the X.Org input driver, and most recently is now used by the latest versions of Mir.

However, Peter noted in the patch series that this gesture recognition might not work out well for all hardware, "on most touchpads we can't distinguish between a three-finger pinch or swipe gesture, the datastream is identical. That happens whenever the index and middle finger are the first to be put on the touchpad. I've considered disabling this for 2-slot touchpads, but since they comprise the majority of touchpads that's not particularly useful. I guess it remains to be seen if misdetection of gestures is a real issue."