nixpkgs/nixos/modules/config/fonts/fontconfig.nix
Jan Tojnar b31c7e527e nixos/fontconfig: Allow setting default emoji font
In fontconfig’s 60-generic.conf, order of preference is estabilished for emoji
font family. Because fontconfig parses the config files in lexicographic order,
appending each <prefer> from <alias> element to the family’s prefer list
(to be prepended before the family) [1], our font family defaults stored
in 52-nixos-default-fonts.conf will take precedence. That is, of course, unless
the default „weak“ binding [2] is used. Emoji family binds strongly [3],
so we need to set binding to “same” for our <alias>es to be considered before
the ones from 60-generic.conf.

By default, we will set the option to all emoji fonts supported by fontconfig,
so that emoji works for user if they have at least one emoji font installed.
If they have multiple emoji fonts installed, we will use the fontconfig’s
order of preference [4].

[1]: https://github.com/bohoomil/fontconfig-ultimate/issues/51#issuecomment-64678322
[2]: https://www.freedesktop.org/software/fontconfig/fontconfig-user.html#AEN25
[3]: cc8442dec8
[4]: c41c922018
2019-09-01 00:09:25 -04:00

477 lines
15 KiB
Nix

/*
NixOS support 2 fontconfig versions, "support" and "latest".
- "latest" refers to default fontconfig package (pkgs.fontconfig).
configuration files are linked to /etc/fonts/VERSION/conf.d/
- "support" refers to supportPkg (pkgs."fontconfig_${supportVersion}").
configuration files are linked to /etc/fonts/conf.d/
This module generates a package containing configuration files and link it in /etc/fonts.
Fontconfig reads files in folder name / file name order, so the number prepended to the configuration file name decide the order of parsing.
Low number means high priority.
*/
{ config, pkgs, lib, ... }:
with lib;
let
cfg = config.fonts.fontconfig;
fcBool = x: "<bool>" + (boolToString x) + "</bool>";
# back-supported fontconfig version and package
# version is used for font cache generation
supportVersion = "210";
supportPkg = pkgs."fontconfig_${supportVersion}";
# latest fontconfig version and package
# version is used for configuration folder name, /etc/fonts/VERSION/
# note: format differs from supportVersion and can not be used with makeCacheConf
latestVersion = pkgs.fontconfig.configVersion;
latestPkg = pkgs.fontconfig;
# supported version fonts.conf
supportFontsConf = pkgs.makeFontsConf { fontconfig = supportPkg; fontDirectories = config.fonts.fonts; };
# configuration file to read fontconfig cache
# version dependent
# priority 0
cacheConfSupport = makeCacheConf { version = supportVersion; };
cacheConfLatest = makeCacheConf {};
# generate the font cache setting file for a fontconfig version
# use latest when no version is passed
makeCacheConf = { version ? null }:
let
fcPackage = if version == null
then "fontconfig"
else "fontconfig_${version}";
makeCache = fontconfig: pkgs.makeFontsCache { inherit fontconfig; fontDirectories = config.fonts.fonts; };
cache = makeCache pkgs."${fcPackage}";
cache32 = makeCache pkgs.pkgsi686Linux."${fcPackage}";
in
pkgs.writeText "fc-00-nixos-cache.conf" ''
<?xml version='1.0'?>
<!DOCTYPE fontconfig SYSTEM 'fonts.dtd'>
<fontconfig>
<!-- Font directories -->
${concatStringsSep "\n" (map (font: "<dir>${font}</dir>") config.fonts.fonts)}
<!-- Pre-generated font caches -->
<cachedir>${cache}</cachedir>
${optionalString (pkgs.stdenv.isx86_64 && cfg.cache32Bit) ''
<cachedir>${cache32}</cachedir>
''}
</fontconfig>
'';
# rendering settings configuration file
# priority 10
renderConf = pkgs.writeText "fc-10-nixos-rendering.conf" ''
<?xml version='1.0'?>
<!DOCTYPE fontconfig SYSTEM 'fonts.dtd'>
<fontconfig>
<!-- Default rendering settings -->
<match target="pattern">
<edit mode="append" name="hinting">
${fcBool cfg.hinting.enable}
</edit>
<edit mode="append" name="autohint">
${fcBool cfg.hinting.autohint}
</edit>
<edit mode="append" name="hintstyle">
<const>hintslight</const>
</edit>
<edit mode="append" name="antialias">
${fcBool cfg.antialias}
</edit>
<edit mode="append" name="rgba">
<const>${cfg.subpixel.rgba}</const>
</edit>
<edit mode="append" name="lcdfilter">
<const>lcd${cfg.subpixel.lcdfilter}</const>
</edit>
</match>
${optionalString (cfg.dpi != 0) ''
<match target="pattern">
<edit name="dpi" mode="assign">
<double>${toString cfg.dpi}</double>
</edit>
</match>
''}
</fontconfig>
'';
# local configuration file
localConf = pkgs.writeText "fc-local.conf" cfg.localConf;
# default fonts configuration file
# priority 52
defaultFontsConf =
let genDefault = fonts: name:
optionalString (fonts != []) ''
<alias binding="same">
<family>${name}</family>
<prefer>
${concatStringsSep ""
(map (font: ''
<family>${font}</family>
'') fonts)}
</prefer>
</alias>
'';
in
pkgs.writeText "fc-52-nixos-default-fonts.conf" ''
<?xml version='1.0'?>
<!DOCTYPE fontconfig SYSTEM 'fonts.dtd'>
<fontconfig>
<!-- Default fonts -->
${genDefault cfg.defaultFonts.sansSerif "sans-serif"}
${genDefault cfg.defaultFonts.serif "serif"}
${genDefault cfg.defaultFonts.monospace "monospace"}
${genDefault cfg.defaultFonts.emoji "emoji"}
</fontconfig>
'';
# bitmap font options
# priority 53
rejectBitmaps = pkgs.writeText "fc-53-no-bitmaps.conf" ''
<?xml version="1.0"?>
<!DOCTYPE fontconfig SYSTEM "fonts.dtd">
<fontconfig>
${optionalString (!cfg.allowBitmaps) ''
<!-- Reject bitmap fonts -->
<selectfont>
<rejectfont>
<pattern>
<patelt name="scalable"><bool>false</bool></patelt>
</pattern>
</rejectfont>
</selectfont>
''}
<!-- Use embedded bitmaps in fonts like Calibri? -->
<match target="font">
<edit name="embeddedbitmap" mode="assign">
${fcBool cfg.useEmbeddedBitmaps}
</edit>
</match>
</fontconfig>
'';
# reject Type 1 fonts
# priority 53
rejectType1 = pkgs.writeText "fc-53-nixos-reject-type1.conf" ''
<?xml version="1.0"?>
<!DOCTYPE fontconfig SYSTEM "fonts.dtd">
<fontconfig>
<!-- Reject Type 1 fonts -->
<selectfont>
<rejectfont>
<pattern>
<patelt name="fontformat"><string>Type 1</string></patelt>
</pattern>
</rejectfont>
</selectfont>
</fontconfig>
'';
# fontconfig configuration package
confPkg = pkgs.runCommand "fontconfig-conf" {
preferLocalBuild = true;
} ''
support_folder=$out/etc/fonts/conf.d
latest_folder=$out/etc/fonts/${latestVersion}/conf.d
mkdir -p $support_folder
mkdir -p $latest_folder
# fonts.conf
ln -s ${supportFontsConf} $support_folder/../fonts.conf
ln -s ${latestPkg.out}/etc/fonts/fonts.conf \
$latest_folder/../fonts.conf
# fontconfig default config files
ln -s ${supportPkg.out}/etc/fonts/conf.d/*.conf \
$support_folder/
ln -s ${latestPkg.out}/etc/fonts/conf.d/*.conf \
$latest_folder/
# update latest 51-local.conf path to look at the latest local.conf
rm $latest_folder/51-local.conf
substitute ${latestPkg.out}/etc/fonts/conf.d/51-local.conf \
$latest_folder/51-local.conf \
--replace local.conf /etc/fonts/${latestVersion}/local.conf
# 00-nixos-cache.conf
ln -s ${cacheConfSupport} \
$support_folder/00-nixos-cache.conf
ln -s ${cacheConfLatest} $latest_folder/00-nixos-cache.conf
# 10-nixos-rendering.conf
ln -s ${renderConf} $support_folder/10-nixos-rendering.conf
ln -s ${renderConf} $latest_folder/10-nixos-rendering.conf
# 50-user.conf
${optionalString (!cfg.includeUserConf) ''
rm $support_folder/50-user.conf
rm $latest_folder/50-user.conf
''}
# local.conf (indirect priority 51)
${optionalString (cfg.localConf != "") ''
ln -s ${localConf} $support_folder/../local.conf
ln -s ${localConf} $latest_folder/../local.conf
''}
# 52-nixos-default-fonts.conf
ln -s ${defaultFontsConf} $support_folder/52-nixos-default-fonts.conf
ln -s ${defaultFontsConf} $latest_folder/52-nixos-default-fonts.conf
# 53-no-bitmaps.conf
ln -s ${rejectBitmaps} $support_folder/53-no-bitmaps.conf
ln -s ${rejectBitmaps} $latest_folder/53-no-bitmaps.conf
${optionalString (!cfg.allowType1) ''
# 53-nixos-reject-type1.conf
ln -s ${rejectType1} $support_folder/53-nixos-reject-type1.conf
ln -s ${rejectType1} $latest_folder/53-nixos-reject-type1.conf
''}
'';
# Package with configuration files
# this merge all the packages in the fonts.fontconfig.confPackages list
fontconfigEtc = pkgs.buildEnv {
name = "fontconfig-etc";
paths = cfg.confPackages;
ignoreCollisions = true;
};
in
{
options = {
fonts = {
fontconfig = {
enable = mkOption {
type = types.bool;
default = true;
description = ''
If enabled, a Fontconfig configuration file will be built
pointing to a set of default fonts. If you don't care about
running X11 applications or any other program that uses
Fontconfig, you can turn this option off and prevent a
dependency on all those fonts.
'';
};
confPackages = mkOption {
internal = true;
type = with types; listOf path;
default = [ ];
description = ''
Fontconfig configuration packages.
'';
};
antialias = mkOption {
type = types.bool;
default = true;
description = ''
Enable font antialiasing. At high resolution (> 200 DPI),
antialiasing has no visible effect; users of such displays may want
to disable this option.
'';
};
dpi = mkOption {
type = types.int;
default = 0;
description = ''
Force DPI setting. Setting to <literal>0</literal> disables DPI
forcing; the DPI detected for the display will be used.
'';
};
localConf = mkOption {
type = types.lines;
default = "";
description = ''
System-wide customization file contents, has higher priority than
<literal>defaultFonts</literal> settings.
'';
};
defaultFonts = {
monospace = mkOption {
type = types.listOf types.str;
default = ["DejaVu Sans Mono"];
description = ''
System-wide default monospace font(s). Multiple fonts may be
listed in case multiple languages must be supported.
'';
};
sansSerif = mkOption {
type = types.listOf types.str;
default = ["DejaVu Sans"];
description = ''
System-wide default sans serif font(s). Multiple fonts may be
listed in case multiple languages must be supported.
'';
};
serif = mkOption {
type = types.listOf types.str;
default = ["DejaVu Serif"];
description = ''
System-wide default serif font(s). Multiple fonts may be listed
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 = {
enable = mkOption {
type = types.bool;
default = true;
description = ''
Enable font hinting. Hinting aligns glyphs to pixel boundaries to
improve rendering sharpness at low resolution. At high resolution
(> 200 dpi) hinting will do nothing (at best); users of such
displays may want to disable this option.
'';
};
autohint = mkOption {
type = types.bool;
default = false;
description = ''
Enable the autohinter in place of the default interpreter.
The results are usually lower quality than correctly-hinted
fonts, but better than unhinted fonts.
'';
};
};
includeUserConf = mkOption {
type = types.bool;
default = true;
description = ''
Include the user configuration from
<filename>~/.config/fontconfig/fonts.conf</filename> or
<filename>~/.config/fontconfig/conf.d</filename>.
'';
};
subpixel = {
rgba = mkOption {
default = "rgb";
type = types.enum ["rgb" "bgr" "vrgb" "vbgr" "none"];
description = ''
Subpixel order. The overwhelming majority of displays are
<literal>rgb</literal> in their normal orientation. Select
<literal>vrgb</literal> for mounting such a display 90 degrees
clockwise from its normal orientation or <literal>vbgr</literal>
for mounting 90 degrees counter-clockwise. Select
<literal>bgr</literal> in the unlikely event of mounting 180
degrees from the normal orientation. Reverse these directions in
the improbable event that the display's native subpixel order is
<literal>bgr</literal>.
'';
};
lcdfilter = mkOption {
default = "default";
type = types.enum ["none" "default" "light" "legacy"];
description = ''
FreeType LCD filter. At high resolution (> 200 DPI), LCD filtering
has no visible effect; users of such displays may want to select
<literal>none</literal>.
'';
};
};
cache32Bit = mkOption {
default = false;
type = types.bool;
description = ''
Generate system fonts cache for 32-bit applications.
'';
};
allowBitmaps = mkOption {
type = types.bool;
default = true;
description = ''
Allow bitmap fonts. Set to <literal>false</literal> to ban all
bitmap fonts.
'';
};
allowType1 = mkOption {
type = types.bool;
default = false;
description = ''
Allow Type-1 fonts. Default is <literal>false</literal> because of
poor rendering.
'';
};
useEmbeddedBitmaps = mkOption {
type = types.bool;
default = false;
description = ''Use embedded bitmaps in fonts like Calibri.'';
};
};
};
};
config = mkMerge [
(mkIf cfg.enable {
environment.systemPackages = [ pkgs.fontconfig ];
environment.etc.fonts.source = "${fontconfigEtc}/etc/fonts/";
})
(mkIf (cfg.enable && !cfg.penultimate.enable) {
fonts.fontconfig.confPackages = [ confPkg ];
})
];
}