There is a bit of information missing on this, namely: how are you going to cooperate with the upstream on this project? The last time similar things were asked for on the libinput bugtracker, there was a clear lack of goodwill to have a PR accepted even if it sang, danced, and made sandwiches for you.
AFAIK, the multitouch problem is with DE and application support and not with libinput, Gnome does support 4 finger gestures, pinch to zoom in images (EoG) and pdf files (Evince) and even 2 fingers back/forward (Epiphany), I don’t know if other DE support it (Elementary’s Pantheon is going to support it on the upcoming version 6) and even Gnome don’t seem to give it too much of a focus. Chrome(ium), that is the most used browser, touchpad support is laughable, it doesn’t even support inertial scrolling like Firefox on Wayland.
On Firefox 76 on MacOS, the text is crammed into a tiny, unreadable box: https://imgur.com/5s65fM6
There is a bit of information missing on this, namely: how are you going to cooperate with the upstream on this project? The last time similar things were asked for on the libinput bugtracker, there was a clear lack of goodwill to have a PR accepted even if it sang, danced, and made sandwiches for you.
Have you taken a look at this project: https://github.com/iberianpig/fusuma
It might be make sense to combine your efforts as it seems that they already have made a lot of headway in supporting gestures with libinput.
AFAIK, the multitouch problem is with DE and application support and not with libinput, Gnome does support 4 finger gestures, pinch to zoom in images (EoG) and pdf files (Evince) and even 2 fingers back/forward (Epiphany), I don’t know if other DE support it (Elementary’s Pantheon is going to support it on the upcoming version 6) and even Gnome don’t seem to give it too much of a focus. Chrome(ium), that is the most used browser, touchpad support is laughable, it doesn’t even support inertial scrolling like Firefox on Wayland.