Custom Keyboard Layout on NixOS, revisited
Roughly two years ago I already wrote an article
on how I configured my customized keyboard layout on NixOS. Unfortunately this broke
some months ago and so far I never really had the time to track down what’s going wrong.
Instead I had a little xmodmap file around, that tweaks the layout after applying the
base layout with setxkbmap us dvp.
Of course this was annoying, after each and every home-manager switch or
nixos-rebuild switch I had to re-apply the changed layout. Also after (re-)attaching
the USB keyboard, etc.
So I finally sat down, … at first trying to just override xorg.xkeyboardconfig. Turns
out that still is a bad idea, at least if you don’t want to compile large parts of your
system locally. So there must be a better way, and just touching setxkbmap and xkbcomp
still feels right. Yet the xserver itself keeps complaining the layout doesn’t exist, even
though setxkbmap accepts it. (and also nixos-rebuild itself now complains)
Turns out the xorgserver package now provides two extra options
--with-xkb-bin-directory and --with-xkb-path, … and that setting both of them is
necessary. If you just set --with-xkb-path then X.org accepts the layout, yet xkbcomp
fails since it fetches the correct rules (from the overridden package), yet the wrong symbols
file. So just override both :)
And to keep nixos-rebuild happy also override xkbvalidate utility, or specifically:
the libxkbcommon dependency of it, so it also has access to the modified rules & symbols.
So my /etc/nixos/configuration.nix now looks like this:
services.xserver = {
enable = true;
layout = "us";
xkbVariant = "stesie";
xkbOptions = "lv3:ralt_switch";
};
nixpkgs.config = {
packageOverrides = super: rec {
xorg = super.xorg // rec {
xkeyboardconfig_rolf = super.xorg.xkeyboardconfig.overrideAttrs (old: {
patches = [
(builtins.toFile "stesie-dvp.patch" ''
Index: xkeyboard-config-2.17/symbols/us
===================================================================
--- xkeyboard-config-2.17.orig/symbols/us
+++ xkeyboard-config-2.17/symbols/us
@@ -1557,6 +1557,34 @@ xkb_symbols "crd" {
include "compose(rctrl)"
};
+partial alphanumeric_keys
+xkb_symbols "stesie" {
+
+ include "us(dvp)"
+ name[Group1] = "English (Modified Programmer Dvorak)";
+
+ // Unmodified Shift AltGr Shift+AltGr
+ // symbols row, left side
+ key <AE01> { [ ampersand, 1 ] };
+ key <AE02> { [ bracketleft, 2, currency ], type[Group1] = "FOUR_LEVEL_ALPHABETIC" };
+ key <AE03> { [ braceleft, 3, cent ], type[Group1] = "FOUR_LEVEL_ALPHABETIC" };
+ key <AE04> { [ braceright, 4, yen ], type[Group1] = "FOUR_LEVEL_ALPHABETIC" };
+ key <AE05> { [ parenleft, 5, EuroSign ], type[Group1] = "FOUR_LEVEL_ALPHABETIC" };
+ key <AE06> { [ equal, 6, sterling ], type[Group1] = "FOUR_LEVEL_ALPHABETIC" };
+
+ // symbols row, right side
+ key <AE07> { [ asterisk, 7 ], type[Group1] = "FOUR_LEVEL_ALPHABETIC" };
+ key <AE08> { [ parenright, 8, onehalf ], type[Group1] = "FOUR_LEVEL_ALPHABETIC" };
+ key <AE09> { [ plus, 9 ], type[Group1] = "FOUR_LEVEL_ALPHABETIC" };
+ key <AE10> { [ bracketright, 0 ], type[Group1] = "FOUR_LEVEL_ALPHABETIC" };
+ key <AE11> { [ exclam, percent, exclamdown ], type[Group1] = "FOUR_LEVEL_ALPHABETIC" };
+ key <AE12> { [ numbersign, grave, dead_grave ] };
+
+ // home row, left side
+ key <AC01> { [ a, A, adiaeresis, Adiaeresis ] };
+ key <AC02> { [ o, O, odiaeresis, Odiaeresis ] };
+ key <AC04> { [ u, U, udiaeresis, Udiaeresis ] };
+};
partial alphanumeric_keys
xkb_symbols "sun_type6" {
Index: xkeyboard-config-2.17/rules/evdev.xml.in
===================================================================
--- xkeyboard-config-2.17.orig/rules/evdev.xml.in
+++ xkeyboard-config-2.17/rules/evdev.xml.in
@@ -1401,6 +1401,12 @@
</variant>
<variant>
<configItem>
+ <name>stesie</name>
+ <description>English (Modified Programmer Dvorak)</description>
+ </configItem>
+ </variant>
+ <variant>
+ <configItem>
<name>rus</name>
<!-- Keyboard indicator for Russian layouts -->
<_shortDescription>ru</_shortDescription>
'')
];
}); # xorg.xkeyboardconfig_rolf
xorgserver = super.xorg.xorgserver.overrideAttrs (old: {
configureFlags = old.configureFlags ++ [
"--with-xkb-bin-directory=${xkbcomp}/bin"
"--with-xkb-path=${xkeyboardconfig_rolf}/share/X11/xkb"
];
});
setxkbmap = super.xorg.setxkbmap.overrideAttrs (old: {
postInstall =
''
mkdir -p $out/share
ln -sfn ${xkeyboardconfig_rolf}/etc/X11 $out/share/X11
'';
});
xkbcomp = super.xorg.xkbcomp.overrideAttrs (old: {
configureFlags = "--with-xkb-config-root=${xkeyboardconfig_rolf}/share/X11/xkb";
});
}; # xorg
xkbvalidate = super.xkbvalidate.override {
libxkbcommon = super.libxkbcommon.override {
xkeyboard_config = xorg.xkeyboardconfig_rolf;
};
};
};
};