1 files changed, 81 insertions, 0 deletions
diff --git a/nixos/modules/config/fonts/fonts.nix b/nixos/modules/config/fonts/fonts.nix
new file mode 100644
index 00000000000..adc6654afc7
--- /dev/null
+++ b/nixos/modules/config/fonts/fonts.nix
@@ -0,0 +1,81 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  # A scalable variant of the X11 "core" cursor
+  #
+  # If not running a fancy desktop environment, the cursor is likely set to
+  # the default `cursor.pcf` bitmap font. This is 17px wide, so it's very
+  # small and almost invisible on 4K displays.
+  fontcursormisc_hidpi = pkgs.xorg.fontxfree86type1.overrideAttrs (old:
+    let
+      # The scaling constant is 230/96: the scalable `left_ptr` glyph at
+      # about 23 points is rendered as 17px, on a 96dpi display.
+      # Note: the XLFD font size is in decipoints.
+      size = 2.39583 * config.services.xserver.dpi;
+      sizeString = builtins.head (builtins.split "\\." (toString size));
+    in
+    {
+      postInstall = ''
+        alias='cursor -xfree86-cursor-medium-r-normal--0-${sizeString}-0-0-p-0-adobe-fontspecific'
+        echo "$alias" > $out/lib/X11/fonts/Type1/fonts.alias
+      '';
+    });
+
+  hasHidpi =
+    config.hardware.video.hidpi.enable &&
+    config.services.xserver.dpi != null;
+
+  defaultFonts =
+    [ pkgs.dejavu_fonts
+      pkgs.freefont_ttf
+      pkgs.gyre-fonts # TrueType substitutes for standard PostScript fonts
+      pkgs.liberation_ttf
+      pkgs.unifont
+      pkgs.noto-fonts-emoji
+    ];
+
+  defaultXFonts =
+    [ (if hasHidpi then fontcursormisc_hidpi else pkgs.xorg.fontcursormisc)
+      pkgs.xorg.fontmiscmisc
+    ];
+
+in
+
+{
+  imports = [
+    (mkRemovedOptionModule [ "fonts" "enableCoreFonts" ] "Use fonts.fonts = [ pkgs.corefonts ]; instead.")
+  ];
+
+  options = {
+
+    fonts = {
+
+      # TODO: find another name for it.
+      fonts = mkOption {
+        type = types.listOf types.path;
+        default = [];
+        example = literalExpression "[ pkgs.dejavu_fonts ]";
+        description = "List of primary font paths.";
+      };
+
+      enableDefaultFonts = mkOption {
+        type = types.bool;
+        default = false;
+        description = ''
+          Enable a basic set of fonts providing several font styles
+          and families and reasonable coverage of Unicode.
+        '';
+      };
+
+    };
+
+  };
+
+  config = mkMerge [
+    { fonts.fonts = mkIf config.fonts.enableDefaultFonts defaultFonts; }
+    { fonts.fonts = mkIf config.services.xserver.enable defaultXFonts; }
+  ];
+
+}