Custom keyboard layout in Wayland like Xmodmap in X11

Revision history
Tags: x11 wayland gnome

Preface

Earlier I used .Xmodmap to define my custom keyboard layout for Norwegian characters behind Caps-Lock. It was surprisingly easy, as described in an earlier blog post. (gist)

However, moving to Wayland, this no longer works. It was actually surprisingly hard to get right.

As of writing I’m on GDM (Gnome Display Manager) in gnome-shell on Arch Linux, but this may apply to other Display Managers under Wayland as well.

Configuring a custom keyboard layout in Wayland

My old .Xmodmap, it looked like this:

clear lock
!Maps Caps-Lock as Level3 Shift
keycode 66 = Mode_switch ISO_Level3_Shift

!Norwegian chars ÆØÅ
keycode 47 = semicolon colon oslash Oslash
keycode 48 = apostrophe quotedbl ae AE
keycode 34 = bracketleft braceleft aring Aring

This gives me Norwegian characters when I hold the Caps-Lock key and press the bounded keys. The keycodes used above can be identified using xev.

For Wayland it has to be split up into two portions. One new file, containing the key bindings goes into */usr/share/X11/xkb/symbols/*.

To see how other layouts are configured, you can look through the files in the same directory. I am using the English (US, euro on 5) as my reference since it is the base layout I’m interested in overriding.

The contents of my stigok keyboard layout looks like this:

default partial alphanumeric_keys

// Overriding the existing us(euro) symbols
// May not be necessary, but it works
xkb_symbols "euro" {

    // Contents of original us(euro)
    include "us(basic)"
    name[Group1]= "STIGOK US English (Norwegian chars behind Caps-Lock)";

    include "eurosign(5)"
    include "level3(ralt_switch)"
    // End contents of original us(euro)

    // Norwegian keys hiding in Level 3
    key <AC10> { [ semicolon, colon, oslash, Oslash ] };
    key <AC11> { [ apostrophe, quotedbl, ae, AE ] };
    key <AD11> { [ bracketleft, braceleft, aring, Aring ] };

    // Toggle Level 3 with Caps-Lock
    key <CAPS> { [ ISO_Level3_Shift ] };

};

Now, to get this visible for the Display Manager, I am adding a new node to the /usr/share/X11/xkb/rules/evdev.xml file under the Xpath /xkbConfigRegistry/layoutList:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE xkbConfigRegistry SYSTEM "xkb.dtd">
<xkbConfigRegistry version="1.1">
  <modelList>
    <!--[redacted]-->
  </modelList>
  <layoutList>
    <layout>
      <configItem>
        <name>stigok</name>
        <shortDescription>en</shortDescription>
        <description>STIGOK English (US)</description>
        <languageList>
          <iso639Id>eng</iso639Id>
        </languageList>
      </configItem>
      <!--[redacted]-->
    </layout>
<!--[redacted]-->

I.e. the only portion you need to add is the <layout>...</layout> under <layoutList>.

Now you have to restart Gnome. In Wayland it can’t be done using Alt+F2 -> R, so I’m restarting by either killing all processes named something with Wayland, or I restart the GDM service systemctl restart gdm.service.

Now you should have something like the below images.

Adding new keyboard layout GDM gnome-shell searching by name

GDM gnome-shell settings custom keyboard layout

Improvements

Putting the configuration in home directory dotfiles

I tried to configure this in my $HOME/.config/xkb instead, but I was unable to get it working properly. The first hurdle was to make sure the $XDG_CONFIG_HOME was actually set to ~/.config. That was solved by setting the variable in /etc/security/pam_env.conf, since it’s no longer set automatically in Arch Linux.

XDG_CONFIG_HOME DEFAULT=${HOME}/.config

I think I have to import complete layouts there to get it working. Something for later, I guess.

Update: as the comments in the pam_env.conf file says, $HOME might not always be set for the calling applications. This seemed to set the path for xkb correctly, but not for lpass (of all things), which had the XDF_CONFIG_HOME set as /.config/lpass instead of ~/.config/lpass. This need further investigation to get working properly.

References

If you have any comments or feedback, please send me an e-mail. (stig at stigok dotcom).

Did you find any typos, incorrect information, or have something to add? Then please propose a change to this post.