How to enable both edge and twofinger modes in libinput.touchpad?

Help
1

I want to be able to scroll on my touchpad using both edge mode and twofinger modes. This is possible on Ubuntu. How to do it on NixOS?

services.xserver = {
    libinput.touchpad = {
      naturalScrolling = true;
      scrollMethod = "edge";
    };
};
2

How are you doing it on Ubuntu?

Maybe you can use the additionalOptions option?

3

Upon further inspections, I’ve come to understand that unfortunately the upstream libinput does not support both twofinger and edge modes at the same time.
So if this feature is of interest, we have to use the abandoned synaptics driver like this:
In Debian:

$ cat /etc/X11/xorg.conf.d/70-synaptics.conf
Section "InputClass"
        Identifier          "touchpad"
        MatchIsTouchpad     "on"
        Driver              "synaptics"
        Option              "VertEdgeScroll"       "on"
        Option              "HorizEdgeScroll"      "on"
        Option              "VertTwoFingerScroll"  "on"
        Option              "HorizTwoFingerScroll" "on"
EndSection

In NixOS, probably one can look at the equivalent configuration from here.

I’ve used this package xserver-xorg-input-synaptics and a config that overrides libinput.