fonts-conf
Name
fonts.conf -- Font configuration files
Synopsis
/etc/fonts/fonts.conf
/etc/fonts/fonts.dtd
/etc/fonts/conf.d
$XDG_CONFIG_HOME/fontconfig/conf.d
$XDG_CONFIG_HOME/fontconfig/fonts.conf
~/.fonts.conf.d
~/.fonts.conf
Description
Fontconfig is a library designed to provide system-wide font
configuration, customization and application access.
Functional Overview
Fontconfig contains two essential modules, the configuration
module which builds an internal configuration from XML files
and the matching module which accepts font patterns and returns
the nearest matching font.
Font Configuration
The configuration module consists of the FcConfig datatype,
libexpat and FcConfigParse which walks over an XML tree and
amends a configuration with data found within. From an external
perspective, configuration of the library consists of
generating a valid XML tree and feeding that to FcConfigParse.
The only other mechanism provided to applications for changing
the running configuration is to add fonts and directories to
the list of application-provided font files.
The intent is to make font configurations relatively static,
and shared by as many applications as possible. It is hoped
that this will lead to more stable font selection when passing
names from one application to another. XML was chosen as a
configuration file format because it provides a format which is
easy for external agents to edit while retaining the correct
structure and syntax.
Font configuration is separate from font matching; applications
needing to do their own matching can access the available fonts
from the library and perform private matching. The intent is to
permit applications to pick and choose appropriate
functionality from the library instead of forcing them to
choose between this library and a private configuration
mechanism. The hope is that this will ensure that configuration
of fonts for all applications can be centralized in one place.
Centralizing font configuration will simplify and regularize
font installation and customization.
Font Properties
While font patterns may contain essentially any properties,
there are some well known properties with associated types.
Fontconfig uses some of these properties for font matching and
font completion. Others are provided as a convenience for the
applications' rendering mechanism.
Property Type Description
--------------------------------------------------------------
family String Font family names
familylang String Languages corresponding to each family
style String Font style. Overrides weight and slant
stylelang String Languages corresponding to each style
fullname String Font full names (often includes style)
fullnamelang String Languages corresponding to each fullname
slant Int Italic, oblique or roman
weight Int Light, medium, demibold, bold or black
size Double Point size
width Int Condensed, normal or expanded
aspect Double Stretches glyphs horizontally before hinting
pixelsize Double Pixel size
spacing Int Proportional, dual-width, monospace or charcel
l
foundry String Font foundry name
antialias Bool Whether glyphs can be antialiased
hinting Bool Whether the rasterizer should use hinting
hintstyle Int Automatic hinting style
verticallayout Bool Use vertical layout
autohint Bool Use autohinter instead of normal hinter
globaladvance Bool Use font global advance data (deprecated)
file String The filename holding the font
index Int The index of the font within the file
ftface FT_Face Use the specified FreeType face object
rasterizer String Which rasterizer is in use (deprecated)
outline Bool Whether the glyphs are outlines
scalable Bool Whether glyphs can be scaled
color Bool Whether any glyphs have color
scale Double Scale factor for point->pixel conversions (dep
recated)
dpi Double Target dots per inch
rgba Int unknown, rgb, bgr, vrgb, vbgr,
none - subpixel geometry
lcdfilter Int Type of LCD filter
minspace Bool Eliminate leading from line spacing
charset CharSet Unicode chars encoded by the font
lang String List of RFC-3066-style languages this
font supports
fontversion Int Version number of the font
capability String List of layout capabilities in the font
fontformat String String name of the font format
embolden Bool Rasterizer should synthetically embolden the f
ont
embeddedbitmap Bool Use the embedded bitmap instead of the outline
decorative Bool Whether the style is a decorative variant
fontfeatures String List of the feature tags in OpenType to be ena
bled
namelang String Language name to be used for the default value
of
familylang, stylelang, and fullnamelang
prgname String String Name of the running program
postscriptname String Font family name in PostScript
fonthashint Bool Whether the font has hinting
order Int Order number of the font
Font Matching
Fontconfig performs matching by measuring the distance from a
provided pattern to all of the available fonts in the system.
The closest matching font is selected. This ensures that a font
will always be returned, but doesn't ensure that it is anything
like the requested pattern.
Font matching starts with an application constructed pattern.
The desired attributes of the resulting font are collected
together in a pattern. Each property of the pattern can contain
one or more values; these are listed in priority order; matches
earlier in the list are considered "closer" than matches later
in the list.
The initial pattern is modified by applying the list of editing
instructions specific to patterns found in the configuration;
each consists of a match predicate and a set of editing
operations. They are executed in the order they appeared in the
configuration. Each match causes the associated sequence of
editing operations to be applied.
After the pattern has been edited, a sequence of default
substitutions are performed to canonicalize the set of
available properties; this avoids the need for the lower layers
to constantly provide default values for various font
properties during rendering.
The canonical font pattern is finally matched against all
available fonts. The distance from the pattern to the font is
measured for each of several properties: foundry, charset,
family, lang, spacing, pixelsize, style, slant, weight,
antialias, rasterizer and outline. This list is in priority
order -- results of comparing earlier elements of this list
weigh more heavily than later elements.
There is one special case to this rule; family names are split
into two bindings; strong and weak. Strong family names are
given greater precedence in the match than lang elements while
weak family names are given lower precedence than lang
elements. This permits the document language to drive font
selection when any document specified font is unavailable.
The pattern representing that font is augmented to include any
properties found in the pattern but not found in the font
itself; this permits the application to pass rendering
instructions or any other data through the matching system.
Finally, the list of editing instructions specific to fonts
found in the configuration are applied to the pattern. This
modified pattern is returned to the application.
The return value contains sufficient information to locate and
rasterize the font, including the file name, pixel size and
other rendering data. As none of the information involved
pertains to the FreeType library, applications are free to use
any rasterization engine or even to take the identified font
file and access it directly.
The match/edit sequences in the configuration are performed in
two passes because there are essentially two different
operations necessary -- the first is to modify how fonts are
selected; aliasing families and adding suitable defaults. The
second is to modify how the selected fonts are rasterized.
Those must apply to the selected font, not the original pattern
as false matches will often occur.
Font Names
Fontconfig provides a textual representation for patterns that
the library can both accept and generate. The representation is
in three parts, first a list of family names, second a list of
point sizes and finally a list of additional properties:
<families>-<point sizes>:<name1>=<values1>:<name2>=<values2>...
Values in a list are separated with commas. The name needn't
include either families or point sizes; they can be elided. In
addition, there are symbolic constants that simultaneously
indicate both a name and a value. Here are some examples:
Name Meaning
----------------------------------------------------------
Times-12 12 point Times Roman
Times-12:bold 12 point Times Bold
Courier:italic Courier Italic in the default size
Monospace:matrix=1 .1 0 1 The users preferred monospace font
with artificial obliquing
The '\', '-', ':' and ',' characters in family names must be
preceded by a '\' character to avoid having them
misinterpreted. Similarly, values containing '\', '=', '_', ':'
and ',' must also have them preceded by a '\' character. The
'\' characters are stripped out of the family name and values
as the font name is read.
Debugging Applications
To help diagnose font and applications problems, fontconfig is
built with a large amount of internal debugging left enabled.
It is controlled by means of the FC_DEBUG environment variable.
The value of this variable is interpreted as a number, and each
bit within that value controls different debugging messages.
Name Value Meaning
---------------------------------------------------------
MATCH 1 Brief information about font matching
MATCHV 2 Extensive font matching information
EDIT 4 Monitor match/test/edit execution
FONTSET 8 Track loading of font information at startup
CACHE 16 Watch cache files being written
CACHEV 32 Extensive cache file writing information
PARSE 64 (no longer in use)
SCAN 128 Watch font files being scanned to build caches
SCANV 256 Verbose font file scanning information
MEMORY 512 Monitor fontconfig memory usage
CONFIG 1024 Monitor which config files are loaded
LANGSET 2048 Dump char sets used to construct lang values
MATCH2 4096 Display font-matching transformation in patterns
Add the value of the desired debug levels together and assign
that (in base 10) to the FC_DEBUG environment variable before
running the application. Output from these statements is sent
to stdout.
Lang Tags
Each font in the database contains a list of languages it
supports. This is computed by comparing the Unicode coverage of
the font with the orthography of each language. Languages are
tagged using an RFC-3066 compatible naming and occur in two
parts -- the ISO 639 language tag followed a hyphen and then by
the ISO 3166 country code. The hyphen and country code may be
elided.
Fontconfig has orthographies for several languages built into
the library. No provision has been made for adding new ones
aside from rebuilding the library. It currently supports 122 of
the 139 languages named in ISO 639-1, 141 of the languages with
two-letter codes from ISO 639-2 and another 30 languages with
only three-letter codes. Languages with both two and three
letter codes are provided with only the two letter code.
For languages used in multiple territories with radically
different character sets, fontconfig includes per-territory
orthographies. This includes Azerbaijani, Kurdish, Pashto,
Tigrinya and Chinese.
Configuration File Format
Configuration files for fontconfig are stored in XML format;
this format makes external configuration tools easier to write
and ensures that they will generate syntactically correct
configuration files. As XML files are plain text, they can also
be manipulated by the expert user using a text editor.
The fontconfig document type definition resides in the external
entity "fonts.dtd"; this is normally stored in the default font
configuration directory (/etc/fonts). Each configuration file
should contain the following structure:
<?xml version="1.0"?>
<!DOCTYPE fontconfig SYSTEM "urn:fontconfig:fonts.dtd">
<fontconfig>
...
</fontconfig>
<fontconfig>
This is the top level element for a font configuration and can
contain <dir>, <cachedir>, <include>, <match> and <alias>
elements in any order.
<dir prefix="default" salt="">
This element contains a directory name which will be scanned
for font files to include in the set of available fonts.
If 'prefix' is set to "default" or "cwd", the current working
directory will be added as the path prefix prior to the value.
If 'prefix' is set to "xdg", the value in the XDG_DATA_HOME
environment variable will be added as the path prefix. please
see XDG Base Directory Specification for more details. If
'prefix' is set to "relative", the path of current file will be
added prior to the value.
'salt' property affects to determine cache filename. this is
useful for example when having different fonts sets on same
path at container and share fonts from host on different font
path.
<cachedir prefix="default">
This element contains a directory name that is supposed to be
stored or read the cache of font information. If multiple
elements are specified in the configuration file, the directory
that can be accessed first in the list will be used to store
the cache files. If it starts with '~', it refers to a
directory in the users home directory. If 'prefix' is set to
"xdg", the value in the XDG_CACHE_HOME environment variable
will be added as the path prefix. please see XDG Base Directory
Specification for more details. The default directory is
``$XDG_CACHE_HOME/fontconfig'' and it contains the cache files
named ``<hash value>-<architecture>.cache-<version>'', where
<version> is the fontconfig cache file version number
(currently 7).
<include ignore_missing="no" prefix="default">
This element contains the name of an additional configuration
file or directory. If a directory, every file within that
directory starting with an ASCII digit (U+0030 - U+0039) and
ending with the string ``.conf'' will be processed in sorted
order. When the XML datatype is traversed by FcConfigParse, the
contents of the file(s) will also be incorporated into the
configuration by passing the filename(s) to
FcConfigLoadAndParse. If 'ignore_missing' is set to "yes"
instead of the default "no", a missing file or directory will
elicit no warning message from the library. If 'prefix' is set
to "xdg", the value in the XDG_CONFIG_HOME environment variable
will be added as the path prefix. please see XDG Base Directory
Specification for more details.
<config>
This element provides a place to consolidate additional
configuration information. <config> can contain <blank> and
<rescan> elements in any order.
<description domain="fontconfig-conf">
This element is supposed to hold strings which describe what a
config is used for. This string can be translated through
gettext. 'domain' needs to be set the proper name to apply
then. fontconfig will tries to retrieve translations with
'domain' from gettext.
<blank>
Fonts often include "broken" glyphs which appear in the
encoding but are drawn as blanks on the screen. Within the
<blank> element, place each Unicode characters which is
supposed to be blank in an <int> element. Characters outside of
this set which are drawn as blank will be elided from the set
of characters supported by the font.
<remap-dir prefix="default" as-path="" salt="">
This element contains a directory name where will be mapped as
the path 'as-path' in cached information. This is useful if the
directory name is an alias (via a bind mount or symlink) to
another directory in the system for which cached font
information is likely to exist.
'salt' property affects to determine cache filename as same as
<dir> element.
<reset-dirs />
This element removes all of fonts directories where added by
<dir> elements. This is useful to override fonts directories
from system to own fonts directories only.
<rescan>
The <rescan> element holds an <int> element which indicates the
default interval between automatic checks for font
configuration changes. Fontconfig will validate all of the
configuration files and directories and automatically rebuild
the internal datastructures when this interval passes.
<selectfont>
This element is used to black/white list fonts from being
listed or matched against. It holds acceptfont and rejectfont
elements.
<acceptfont>
Fonts matched by an acceptfont element are "whitelisted"; such
fonts are explicitly included in the set of fonts used to
resolve list and match requests; including them in this list
protects them from being "blacklisted" by a rejectfont element.
Acceptfont elements include glob and pattern elements which are
used to match fonts.
<rejectfont>
Fonts matched by an rejectfont element are "blacklisted"; such
fonts are excluded from the set of fonts used to resolve list
and match requests as if they didn't exist in the system.
Rejectfont elements include glob and pattern elements which are
used to match fonts.
<glob>
Glob elements hold shell-style filename matching patterns
(including ? and *) which match fonts based on their complete
pathnames. This can be used to exclude a set of directories
(/usr/share/fonts/uglyfont*), or particular font file types
(*.pcf.gz), but the latter mechanism relies rather heavily on
filenaming conventions which can't be relied upon. Note that
globs only apply to directories, not to individual fonts.
<pattern>
Pattern elements perform list-style matching on incoming fonts;
that is, they hold a list of elements and associated values. If
all of those elements have a matching value, then the pattern
matches the font. This can be used to select fonts based on
attributes of the font (scalable, bold, etc), which is a more
reliable mechanism than using file extensions. Pattern elements
include patelt elements.
<patelt name="property">
Patelt elements hold a single pattern element and list of
values. They must have a 'name' attribute which indicates the
pattern element name. Patelt elements include int, double,
string, matrix, bool, charset and const elements.
<match target="pattern">
This element holds first a (possibly empty) list of <test>
elements and then a (possibly empty) list of <edit> elements.
Patterns which match all of the tests are subjected to all the
edits. If 'target' is set to "font" instead of the default
"pattern", then this element applies to the font name resulting
from a match rather than a font pattern to be matched. If
'target' is set to "scan", then this element applies when the
font is scanned to build the fontconfig database.
<test qual="any" name="property" target="default" compare="eq">
This element contains a single value which is compared with the
target ('pattern', 'font', 'scan' or 'default') property
"property" (substitute any of the property names seen above).
'compare' can be one of "eq", "not_eq", "less", "less_eq",
"more", "more_eq", "contains" or "not_contains". 'qual' may
either be the default, "any", in which case the match succeeds
if any value associated with the property matches the test
value, or "all", in which case all of the values associated
with the property must match the test value. 'ignore-blanks'
takes a boolean value. if 'ignore-blanks' is set "true", any
blanks in the string will be ignored on its comparison. this
takes effects only when compare="eq" or compare="not_eq". When
used in a <match target="font"> element, the target= attribute
in the <test> element selects between matching the original
pattern or the font. "default" selects whichever target the
outer <match> element has selected.
<edit name="property" mode="assign" binding="weak">
This element contains a list of expression elements (any of the
value or operator elements). The expression elements are
evaluated at run-time and modify the property "property". The
modification depends on whether "property" was matched by one
of the associated <test> elements, if so, the modification may
affect the first matched value. Any values inserted into the
property are given the indicated binding ("strong", "weak" or
"same") with "same" binding using the value from the matched
pattern element. 'mode' is one of:
Mode With Match Without Match
---------------------------------------------------------------------
"assign" Replace matching value Replace all values
"assign_replace" Replace all values Replace all values
"prepend" Insert before matching Insert at head of list
"prepend_first" Insert at head of list Insert at head of list
"append" Append after matching Append at end of list
"append_last" Append at end of list Append at end of list
"delete" Delete matching value Delete all values
"delete_all" Delete all values Delete all values
<int>, <double>, <string>, <bool>
These elements hold a single value of the indicated type.
<bool> elements hold either true or false. An important
limitation exists in the parsing of floating point numbers --
fontconfig requires that the mantissa start with a digit, not a
decimal point, so insert a leading zero for purely fractional
values (e.g. use 0.5 instead of .5 and -0.5 instead of -.5).
<matrix>
This element holds four numerical expressions of an affine
transformation. At their simplest these will be four <double>
elements but they can also be more involved expressions.
<range>
This element holds the two <int> elements of a range
representation.
<charset>
This element holds at least one <int> element of an Unicode
code point or more.
<langset>
This element holds at least one <string> element of a
RFC-3066-style languages or more.
<name>
Holds a property name. Evaluates to the first value from the
property of the pattern. If the 'target' attribute is not
present, it will default to 'default', in which case the
property is returned from the font pattern during a
target="font" match, and to the pattern during a
target="pattern" match. The attribute can also take the values
'font' or 'pattern' to explicitly choose which pattern to use.
It is an error to use a target of 'font' in a match that has
target="pattern".
<const>
Holds the name of a constant; these are always integers and
serve as symbolic names for common font values:
Constant Property Value
-------------------------------------
thin weight 0
extralight weight 40
ultralight weight 40
light weight 50
demilight weight 55
semilight weight 55
book weight 75
regular weight 80
normal weight 80
medium weight 100
demibold weight 180
semibold weight 180
bold weight 200
extrabold weight 205
black weight 210
heavy weight 210
roman slant 0
italic slant 100
oblique slant 110
ultracondensed width 50
extracondensed width 63
condensed width 75
semicondensed width 87
normal width 100
semiexpanded width 113
expanded width 125
extraexpanded width 150
ultraexpanded width 200
proportional spacing 0
dual spacing 90
mono spacing 100
charcell spacing 110
unknown rgba 0
rgb rgba 1
bgr rgba 2
vrgb rgba 3
vbgr rgba 4
none rgba 5
lcdnone lcdfilter 0
lcddefault lcdfilter 1
lcdlight lcdfilter 2
lcdlegacy lcdfilter 3
hintnone hintstyle 0
hintslight hintstyle 1
hintmedium hintstyle 2
hintfull hintstyle 3
<or>, <and>, <plus>, <minus>, <times>, <divide>
These elements perform the specified operation on a list of
expression elements. <or> and <and> are boolean, not bitwise.
<eq>, <not_eq>, <less>, <less_eq>, <more>, <more_eq>, <contains>,
<not_contains
These elements compare two values, producing a boolean result.
<not>
Inverts the boolean sense of its one expression element
<if>
This element takes three expression elements; if the value of
the first is true, it produces the value of the second,
otherwise it produces the value of the third.
<alias>
Alias elements provide a shorthand notation for the set of
common match operations needed to substitute one font family
for another. They contain a <family> element followed by
optional <prefer>, <accept> and <default> elements. Fonts
matching the <family> element are edited to prepend the list of
<prefer>ed families before the matching <family>, append the
<accept>able families after the matching <family> and append
the <default> families to the end of the family list.
<family>
Holds a single font family name
<prefer>, <accept>, <default>
These hold a list of <family> elements to be used by the
<alias> element.
EXAMPLE CONFIGURATION FILE
System configuration file
This is an example of a system-wide configuration file
<?xml version="1.0"?>
<!DOCTYPE fontconfig SYSTEM "urn:fontconfig:fonts.dtd">
<!-- /etc/fonts/fonts.conf file to configure system font access -->
<fontconfig>
<!--
Find fonts in these directories
-->
<dir>/usr/share/fonts</dir>
<dir>/usr/X11R6/lib/X11/fonts</dir>
<!--
Accept deprecated 'mono' alias, replacing it with 'monospace'
-->
<match target="pattern">
<test qual="any" name="family"><string>mono</string></test>
<edit name="family" mode="assign"><string>monospace</string></ed
it>
</match>
<!--
Names not including any well known alias are given 'sans-serif'
-->
<match target="pattern">
<test qual="all" name="family" compare="not_eq"><string>sans-ser
if</string></test>
<test qual="all" name="family" compare="not_eq"><string>serif</s
tring></test>
<test qual="all" name="family" compare="not_eq"><string>monospac
e</string></test>
<edit name="family" mode="append_last"><string>sans-serif</strin
g></edit>
</match>
<!--
Load per-user customization file, but don't complain
if it doesn't exist
-->
<include ignore_missing="yes" prefix="xdg">fontconfig/fonts.conf</includ
e>
<!--
Load local customization files, but don't complain
if there aren't any
-->
<include ignore_missing="yes">conf.d</include>
<include ignore_missing="yes">local.conf</include>
<!--
Alias well known font names to available TrueType fonts.
These substitute TrueType faces for similar Type1
faces to improve screen appearance.
-->
<alias>
<family>Times</family>
<prefer><family>Times New Roman</family></prefer>
<default><family>serif</family></default>
</alias>
<alias>
<family>Helvetica</family>
<prefer><family>Arial</family></prefer>
<default><family>sans</family></default>
</alias>
<alias>
<family>Courier</family>
<prefer><family>Courier New</family></prefer>
<default><family>monospace</family></default>
</alias>
<!--
Provide required aliases for standard names
Do these after the users configuration file so that
any aliases there are used preferentially
-->
<alias>
<family>serif</family>
<prefer><family>Times New Roman</family></prefer>
</alias>
<alias>
<family>sans</family>
<prefer><family>Arial</family></prefer>
</alias>
<alias>
<family>monospace</family>
<prefer><family>Andale Mono</family></prefer>
</alias>
<--
The example of the requirements of OR operator;
If the 'family' contains 'Courier New' OR 'Courier'
add 'monospace' as the alternative
-->
<match target="pattern">
<test name="family" compare="eq">
<string>Courier New</string>
</test>
<edit name="family" mode="prepend">
<string>monospace</string>
</edit>
</match>
<match target="pattern">
<test name="family" compare="eq">
<string>Courier</string>
</test>
<edit name="family" mode="prepend">
<string>monospace</string>
</edit>
</match>
</fontconfig>
User configuration file
This is an example of a per-user configuration file that lives
in $XDG_CONFIG_HOME/fontconfig/fonts.conf
<?xml version="1.0"?>
<!DOCTYPE fontconfig SYSTEM "urn:fontconfig:fonts.dtd">
<!-- $XDG_CONFIG_HOME/fontconfig/fonts.conf for per-user font configurat
ion -->
<fontconfig>
<!--
Private font directory
-->
<dir prefix="xdg">fonts</dir>
<!--
use rgb sub-pixel ordering to improve glyph appearance on
LCD screens. Changes affecting rendering, but not matching
should always use target="font".
-->
<match target="font">
<edit name="rgba" mode="assign"><const>rgb</const></edit>
</match>
<!--
use WenQuanYi Zen Hei font when serif is requested for Chinese
-->
<match>
<!--
If you don't want to use WenQuanYi Zen Hei font for zh-t
w etc,
you can use zh-cn instead of zh.
Please note, even if you set zh-cn, it still matches zh.
if you don't like it, you can use compare="eq"
instead of compare="contains".
-->
<test name="lang" compare="contains">
<string>zh</string>
</test>
<test name="family">
<string>serif</string>
</test>
<edit name="family" mode="prepend">
<string>WenQuanYi Zen Hei</string>
</edit>
</match>
<!--
use VL Gothic font when sans-serif is requested for Japanese
-->
<match>
<test name="lang" compare="contains">
<string>ja</string>
</test>
<test name="family">
<string>sans-serif</string>
</test>
<edit name="family" mode="prepend">
<string>VL Gothic</string>
</edit>
</match>
</fontconfig>
Files
fonts.conf contains configuration information for the
fontconfig library consisting of directories to look at for
font information as well as instructions on editing program
specified font patterns before attempting to match the
available fonts. It is in XML format.
conf.d is the conventional name for a directory of additional
configuration files managed by external applications or the
local administrator. The filenames starting with decimal digits
are sorted in lexicographic order and used as additional
configuration files. All of these files are in XML format. The
master fonts.conf file references this directory in an
<include> directive.
fonts.dtd is a DTD that describes the format of the
configuration files.
$XDG_CONFIG_HOME/fontconfig/conf.d and ~/.fonts.conf.d is the
conventional name for a per-user directory of (typically
auto-generated) configuration files, although the actual
location is specified in the global fonts.conf file. please
note that ~/.fonts.conf.d is deprecated now. it will not be
read by default in the future version.
$XDG_CONFIG_HOME/fontconfig/fonts.conf and ~/.fonts.conf is the
conventional location for per-user font configuration, although
the actual location is specified in the global fonts.conf file.
please note that ~/.fonts.conf is deprecated now. it will not
be read by default in the future version.
$XDG_CACHE_HOME/fontconfig/*.cache-* and
~/.fontconfig/*.cache-* is the conventional repository of font
information that isn't found in the per-directory caches. This
file is automatically maintained by fontconfig. please note
that ~/.fontconfig/*.cache-* is deprecated now. it will not be
read by default in the future version.
Environment variables
FONTCONFIG_FILE is used to override the default configuration
file.
FONTCONFIG_PATH is used to override the default configuration
directory.
FONTCONFIG_SYSROOT is used to set a default sysroot directory.
FC_DEBUG is used to output the detailed debugging messages. see
Debugging Applications section for more details.
FC_DBG_MATCH_FILTER is used to filter out the patterns. this
takes a comma-separated list of object names and effects only
when FC_DEBUG has MATCH2. see Debugging Applications section
for more details.
FC_LANG is used to specify the default language as the weak
binding in the query. if this isn't set, the default language
will be determined from current locale.
FONTCONFIG_USE_MMAP is used to control the use of mmap(2) for
the cache files if available. this take a boolean value.
fontconfig will checks if the cache files are stored on the
filesystem that is safe to use mmap(2). explicitly setting this
environment variable will causes skipping this check and
enforce to use or not use mmap(2) anyway.
SOURCE_DATE_EPOCH is used to ensure fc-cache(1) generates files
in a deterministic manner in order to support reproducible
builds. When set to a numeric representation of UNIX timestamp,
fontconfig will prefer this value over using the modification
timestamps of the input files in order to identify which cache
files require regeneration. If SOURCE_DATE_EPOCH is not set (or
is newer than the mtime of the directory), the existing
behaviour is unchanged.
See Also
fc-cat(1), fc-cache(1), fc-list(1), fc-match(1), fc-query(1),
SOURCE_DATE_EPOCH.
Version
Fontconfig version 2.14.1
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