Merge pull request #67667 from jtojnar/default-emoji

nixos/fontconfig: Allow setting default emoji font

nixos/doc/manual/release-notes/rl-1909.xml

@@ -600,6 +600,26 @@
       removed from nixpkgs due to lack of maintainer.
     </para>
    </listitem>
+   <listitem>
+    <para>
+     Using <option>fonts.enableDefaultFonts</option> adds a default emoji font <literal>noto-fonts-emoji</literal>.
+     <itemizedlist>
+      <para>Users of the following options will have this enabled by default:</para>
+      <listitem>
+       <para><option>services.xserver.enable</option></para>
+      </listitem>
+      <listitem>
+       <para><option>programs.sway.enable</option></para>
+      </listitem>
+      <listitem>
+       <para><option>programs.way-cooler.enable</option></para>
+      </listitem>
+      <listitem>
+       <para><option>services.xrdp.enable</option></para>
+      </listitem>
+     </itemizedlist>
+    </para>
+   </listitem>
   </itemizedlist>
  </section>
 </section>

nixos/modules/config/fonts/fontconfig.nix

@@ -116,7 +116,7 @@ let
   defaultFontsConf =
     let genDefault = fonts: name:
       optionalString (fonts != []) ''
-        <alias>
+        <alias binding="same">
           <family>${name}</family>
           <prefer>
           ${concatStringsSep ""
@@ -139,6 +139,8 @@ let
 
       ${genDefault cfg.defaultFonts.monospace "monospace"}
 
+      ${genDefault cfg.defaultFonts.emoji "emoji"}
+
     </fontconfig>
   '';
 
@@ -344,6 +346,21 @@ in
               in case multiple languages must be supported.
             '';
           };
+
+          emoji = mkOption {
+            type = types.listOf types.str;
+            default = ["Noto Color Emoji"];
+            description = ''
+              System-wide default emoji font(s). Multiple fonts may be listed
+              in case a font does not support all emoji.
+
+              Note that fontconfig matches color emoji fonts preferentially,
+              so if you want to use a black and white font while having
+              a color font installed (eg. Noto Color Emoji installed alongside
+              Noto Emoji), fontconfig will still choose the color font even
+              when it is later in the list.
+            '';
+          };
         };
 
         hinting = {

nixos/modules/config/fonts/fonts.nix

@@ -43,6 +43,7 @@ with lib;
         pkgs.xorg.fontmiscmisc
         pkgs.xorg.fontcursormisc
         pkgs.unifont
+        pkgs.noto-fonts-emoji
       ];
 
   };

nixos/release-combined.nix

@@ -68,6 +68,7 @@ in rec {
         nixos.tests.chromium.x86_64-linux or []
         (all nixos.tests.firefox)
         (all nixos.tests.firewall)
+        (all nixos.tests.fontconfig-default-fonts)
         (all nixos.tests.gnome3-xorg)
         (all nixos.tests.gnome3)
         (all nixos.tests.pantheon)

nixos/tests/all-tests.nix

@@ -87,6 +87,7 @@ in
   flatpak = handleTest ./flatpak.nix {};
   flatpak-builder = handleTest ./flatpak-builder.nix {};
   fluentd = handleTest ./fluentd.nix {};
+  fontconfig-default-fonts = handleTest ./fontconfig-default-fonts.nix {};
   fsck = handleTest ./fsck.nix {};
   fwupd = handleTestOn ["x86_64-linux"] ./fwupd.nix {}; # libsmbios is unsupported on aarch64
   gdk-pixbuf = handleTest ./gdk-pixbuf.nix {};

nixos/tests/fontconfig-default-fonts.nix

@@ -0,0 +1,28 @@
+import ./make-test.nix ({ lib, ... }:
+{
+  name = "fontconfig-default-fonts";
+
+  machine = { config, pkgs, ... }: {
+    fonts.enableDefaultFonts = true; # Background fonts
+    fonts.fonts = with pkgs; [
+      noto-fonts-emoji
+      cantarell-fonts
+      twitter-color-emoji
+      source-code-pro
+      gentium
+    ];
+    fonts.fontconfig.defaultFonts = {
+      serif = [ "Gentium Plus" ];
+      sansSerif = [ "Cantarell" ];
+      monospace = [ "Source Code Pro" ];
+      emoji = [ "Twitter Color Emoji" ];
+    };
+  };
+
+  testScript = ''
+    $machine->succeed("fc-match serif | grep '\"Gentium Plus\"'");
+    $machine->succeed("fc-match sans-serif | grep '\"Cantarell\"'");
+    $machine->succeed("fc-match monospace | grep '\"Source Code Pro\"'");
+    $machine->succeed("fc-match emoji | grep '\"Twitter Color Emoji\"'");
+  '';
+})