dotfiles/.config/fontconfig/fonts.conf

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE fontconfig SYSTEM "fonts.dtd">
<fontconfig>
  <!-- Set default fonts -->
  <alias>
    <family>monospace</family>
    <prefer>
      <family>Source Code Pro</family>
      <family>Noto Color Emoji</family>
    </prefer>
  </alias>
  <alias>
    <family>serif</family>
    <prefer>
      <family>Source Serif 4</family>
      <family>Source Serif 3</family>
      <family>Source Serif Pro</family>
      <family>Noto Color Emoji</family>
    </prefer>
  </alias>
  <alias>
    <family>sans-serif</family>
    <prefer>
      <family>Source Sans 3</family>
      <family>Source Sans Pro</family>
      <family>Noto Color Emoji</family>
    </prefer>
  </alias>

  <!-- Add generic emoji family. -->
  <match target="pattern">
    <test qual="any" name="family">
      <string>emoji</string>
    </test>
    <edit name="family" mode="assign" binding="same">
      <string>Noto Color Emoji</string>
    </edit>
  </match>

  <!-- FIXME: Doesn't work -->
  <!--
        If other fonts contain emoji glyphs, they could interfere and make some emojis rendered in wrong font (often in black-and-white).
        For example, DejaVu Sans contains black-and-white emojis, which we can remove using the following trick:
    -->
  <match target="scan">
    <test name="family" compare="contains">
      <string>DejaVu</string>
    </test>
    <edit name="charset" mode="assign" binding="same">
      <minus>
        <name>charset</name>
        <charset>
          <range>
            <int>0x1f600</int>
            <int>0x1f640</int>
          </range>
        </charset>
      </minus>
    </edit>
  </match>

  <!-- Exclude some glyphs from Source* font families -->
  <match target="scan">
    <test name="family" compare="contains">
      <string>Source</string>
    </test>
    <edit name="charset" mode="assign" binding="same">
      <minus>
        <name>charset</name>
        <charset>
          <int>0x2764</int> <!-- red heart -->
          <int>0x2615</int> <!-- hot beverage -->
          <int>0x1f4a9</int> <!-- pile of poo -->
        </charset>
      </minus>
    </edit>
  </match>
</fontconfig>