One thing that didn't carry over from my i3 setup when moving over to Sway (i.e. Wayland) was the touchpad configuration. Input devices was a display server concern under X.Org, so the window manager had nothing to do with it. Notably, now click-on-tap is not working for me, which is massively annoying.

If you're just here for the touchpad click-on-tap configuration, it looks like this.

input "type:touchpad" {
    dwt enabled
    dwtp enabled
    tap enabled
    tap_button_map lrm
}

But if you want to improve your understanding of how to configure input devices such as touchpads and mice in a Wayland compositor, then read on!

Configuring a libinput device in Sway

We need to add a libinput¹ configuration into the Sway config file, which is usually located at ~/.config/sway/config. The Sway wiki has a small example for libinput devices but it doesn't really say all that much. Generally, an input configuration should look like this.

input <selector> {
    option value
}

For the selector, we can use either the device identifier, or the type of the device. I prefer the device type, i.e. "type:touchpad", as I use the same configuration file for multiple devices that don't share touchpad identifiers².

You can run swaymsg -t get_inputs to get information about your devices. You will get a ton of output, but somewhere you'll find a device that has Type: Touchpad. Mine looks like this.

$ swaymsg -t get_inputs
...
Input device: SYNA1D31:00 06CB:CD48 Touchpad
  Type: Touchpad
  Identifier: 1739:52552:SYNA1D31:00_06CB:CD48_Touchpad
  Product ID: 52552
  Vendor ID: 1739
  Libinput Send Events: enabled
...

We can however get a whole lot more information about each device with the --raw option³. Combining that with jq⁴ we can get only touchpads out of the command. On all my devices, I only have a single touchpad device. It should look something like this.

$ swaymsg -t get_inputs --raw | jq '.[] | select(.type=="touchpad")'
{
  "identifier": "1739:52552:SYNA1D31:00_06CB:CD48_Touchpad",
  "name": "SYNA1D31:00 06CB:CD48 Touchpad",
  "vendor": 1739,
  "product": 52552,
  "type": "touchpad",
  "scroll_factor": 1.0,
  "libinput": {
    "send_events": "enabled",
    "tap": "disabled",
    "tap_button_map": "lrm",
    "tap_drag": "enabled",
    "tap_drag_lock": "disabled",
    "accel_speed": 0.0,
    "accel_profile": "adaptive",
    "natural_scroll": "disabled",
    "left_handed": "disabled",
    "click_method": "button_areas",
    "middle_emulation": "disabled",
    "scroll_method": "two_finger",
    "dwt": "enabled",
    "dwtp": "enabled"
  }
}

This gives us everything we need to configure the touchpad, and we can also see if our configuration takes effect correctly. The options shown under libinput is what we have to play with. The names aren't necessarily self-explanatory, but you can find decent descriptions of them in the sway-input(5)⁵man page under the LIBINPUT CONFIGURATION section.

I'm going to set the options that are crucial for how I use a touchpad, regardless of what their defaults are. These options are:

input "type:touchpad" {
    tap enabled         # enables click-on-tap
    tap_button_map lrm  # tap with 1 finger = left click, 2 fingers = right click, 3 fingers = middle click
    dwt enabled         # disable (touchpad) while typing
    dwtp enabled        # disable (touchpad) while track pointing
}

Putting this in my ~/.config/sway/config⁶, reloading the environment and then checking the settings shows that tap is now enabled.

$ swaymsg reload
$ swaymsg -t get_inputs | jq '.[] | select(.type=="touchpad")'
{
  "identifier": "1739:52552:SYNA1D31:00_06CB:CD48_Touchpad",
  [...]
  "libinput": {
    [...]
    "tap": "enabled",
    "tap_button_map": "lrm",
    [...]
    "dwt": "enabled",
    "dwtp": "enabled"
  }
}

And that's that, click-on-tap now works again!

Summary

In this article, I outlined how to configure a touchpad in Sway. The principles shown here carry over to any kind of libinput device, and should also be applicable in most other Wayland compositors.

1. libinput is a stack for common input devices, such as keyboards, touchpads and mice. Read more in the Wayland wiki. ↩
2. Note that the type selector will select all devices of that type. If you have multiple devices that identify as touchpads, you may want to be more specific and use the identifier. ↩
3. When piping swaymsg output to another command, --raw is implicit. I use it here explicitly for clarity. ↩
4. If you don't know how to use jq, do yourself the biggest favor of the year and learn it. ↩
5. Run man 5 sway-input to get the given page. See my article on man page sections if the 5 is confusing to you. ↩
6. To see exactly how I use this in my Sway config, refer to my config repository. ↩