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Import fontconfig 2.4.1
2006-11-25 11:41:30 -07:00
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN""http://www.w3.org/TR/html4/loose.dtd">
<HTML
><HEAD
><TITLE
>fonts-conf</TITLE
><META
NAME="GENERATOR"
CONTENT="Modular DocBook HTML Stylesheet Version 1.79"></HEAD
><BODY
CLASS="REFENTRY"
BGCOLOR="#FFFFFF"
TEXT="#000000"
LINK="#0000FF"
VLINK="#840084"
ALINK="#0000FF"
><H1
><A
NAME="AEN1"
></A
>fonts-conf</H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN5"
></A
><H2
>Name</H2
>fonts.conf&nbsp;--&nbsp;Font configuration files</DIV
><DIV
CLASS="REFSYNOPSISDIV"
><A
NAME="AEN8"
></A
><H2
>Synopsis</H2
><PRE
CLASS="SYNOPSIS"
> /etc/fonts/fonts.conf
/etc/fonts/fonts.dtd
/etc/fonts/conf.d
~/.fonts.conf</PRE
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN10"
></A
><H2
>Description</H2
><P
>Fontconfig is a library designed to provide system-wide font configuration,
customization and application access.
</P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN13"
></A
><H2
>Functional Overview</H2
><P
>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.
</P
><DIV
CLASS="REFSECT2"
><A
NAME="AEN16"
></A
><H3
>Font Configuration</H3
><P
>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.
</P
><P
>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.
</P
><P
>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.
</P
></DIV
><DIV
CLASS="REFSECT2"
><A
NAME="AEN21"
></A
><H3
>Font Properties</H3
><P
>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.
</P
><PRE
CLASS="PROGRAMLISTING"
> 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 charcell
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
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
outline Bool Whether the glyphs are outlines
scalable Bool Whether glyphs can be scaled
scale Double Scale factor for point-&#62;pixel conversions
dpi Double Target dots per inch
rgba Int unknown, rgb, bgr, vrgb, vbgr,
none - subpixel geometry
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
embolden Bool Rasterizer should synthetically embolden the font
</PRE
></DIV
><DIV
CLASS="REFSECT2"
><A
NAME="AEN25"
></A
><H3
>Font Matching</H3
><P
>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.
</P
><P
>
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.
</P
><P
>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.
</P
><P
>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.
</P
><P
>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.
</P
><P
>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.
</P
><P
>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.
</P
><P
>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.
</P
><P
>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.
</P
></DIV
><DIV
CLASS="REFSECT2"
><A
NAME="AEN36"
></A
><H3
>Font Names</H3
><P
>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:
</P
><PRE
CLASS="PROGRAMLISTING"
> &lt;families&gt;-&lt;point sizes&gt;:&lt;name1&gt;=&lt;values1&gt;:&lt;name2&gt;=&lt;values2&gt;...
</PRE
><P
>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:
</P
><PRE
CLASS="PROGRAMLISTING"
> 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
</PRE
><P
>The '\', '-', ':' and ',' characters in family names must be preceeded by a
'\' character to avoid having them misinterpreted. Similarly, values
containing '\', '=', '_', ':' and ',' must also have them preceeded by a
'\' character. The '\' characters are stripped out of the family name and
values as the font name is read.
</P
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN43"
></A
><H2
>Debugging Applications</H2
><P
>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.
</P
><PRE
CLASS="PROGRAMLISTING"
> 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
OBJTYPES 4096 Display message when value typechecks fail
</PRE
><P
>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.
</P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN48"
></A
><H2
>Lang Tags</H2
><P
>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.
</P
><P
>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.
</P
><P
>For languages used in multiple territories with radically different
character sets, fontconfig includes per-territory orthographies. This
includes Azerbaijani, Kurdish, Pashto, Tigrinya and Chinese.
</P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN53"
></A
><H2
>Configuration File Format</H2
><P
>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.
</P
><P
>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:
<PRE
CLASS="PROGRAMLISTING"
> &lt;?xml version="1.0"?&gt;
&lt;!DOCTYPE fontconfig SYSTEM "fonts.dtd"&gt;
&lt;fontconfig&gt;
...
&lt;/fontconfig&gt;
</PRE
>
</P
><DIV
CLASS="REFSECT2"
><A
NAME="AEN58"
></A
><H3
><TT
CLASS="LITERAL"
>&lt;fontconfig&gt;</TT
></H3
><P
>This is the top level element for a font configuration and can contain
<CODE
CLASS="SGMLTAG"
>dir</CODE
>, <CODE
CLASS="SGMLTAG"
>cache</CODE
>, <CODE
CLASS="SGMLTAG"
>include</CODE
>, <CODE
CLASS="SGMLTAG"
>match</CODE
> and <CODE
CLASS="SGMLTAG"
>alias</CODE
> elements in any order.
</P
></DIV
><DIV
CLASS="REFSECT2"
><A
NAME="AEN67"
></A
><H3
><CODE
CLASS="SGMLTAG"
>dir</CODE
></H3
><P
>This element contains a directory name which will be scanned for font files
to include in the set of available fonts.
</P
></DIV
><DIV
CLASS="REFSECT2"
><A
NAME="AEN71"
></A
><H3
><CODE
CLASS="SGMLTAG"
>cache</CODE
></H3
><P
>This element contains a file name for the per-user cache of font
information. If it starts with '~', it refers to a file in the users
home directory. This file is used to hold information about fonts that
isn't present in the per-directory cache files. It is automatically
maintained by the fontconfig library. The default for this file
is ``~/.fonts.cache-<CODE
CLASS="SGMLTAG"
>version</CODE
>'', where <CODE
CLASS="SGMLTAG"
>version</CODE
> is the font configuration
file version number (currently 2).
</P
></DIV
><DIV
CLASS="REFSECT2"
><A
NAME="AEN77"
></A
><H3
><CODE
CLASS="SGMLTAG"
>include ignore_missing="no"</CODE
></H3
><P
>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.
</P
></DIV
><DIV
CLASS="REFSECT2"
><A
NAME="AEN81"
></A
><H3
><CODE
CLASS="SGMLTAG"
>config</CODE
></H3
><P
>This element provides a place to consolidate additional configuration
information. <CODE
CLASS="SGMLTAG"
>config</CODE
> can contain <CODE
CLASS="SGMLTAG"
>blank</CODE
> and <CODE
CLASS="SGMLTAG"
>rescan</CODE
> elements in any
order.
</P
></DIV
><DIV
CLASS="REFSECT2"
><A
NAME="AEN88"
></A
><H3
><CODE
CLASS="SGMLTAG"
>blank</CODE
></H3
><P
>Fonts often include "broken" glyphs which appear in the encoding but are
drawn as blanks on the screen. Within the <CODE
CLASS="SGMLTAG"
>blank</CODE
> element, place each
Unicode characters which is supposed to be blank in an <CODE
CLASS="SGMLTAG"
>int</CODE
> element.
Characters outside of this set which are drawn as blank will be elided from
the set of characters supported by the font.
</P
></DIV
><DIV
CLASS="REFSECT2"
><A
NAME="AEN94"
></A
><H3
><CODE
CLASS="SGMLTAG"
>rescan</CODE
></H3
><P
>The <CODE
CLASS="SGMLTAG"
>rescan</CODE
> element holds an <CODE
CLASS="SGMLTAG"
>int</CODE
> 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.
</P
></DIV
><DIV
CLASS="REFSECT2"
><A
NAME="AEN100"
></A
><H3
><CODE
CLASS="SGMLTAG"
>selectfont</CODE
></H3
><P
>This element is used to black/white list fonts from being listed or matched
against. It holds acceptfont and rejectfont elements.
</P
></DIV
><DIV
CLASS="REFSECT2"
><A
NAME="AEN104"
></A
><H3
><CODE
CLASS="SGMLTAG"
>acceptfont</CODE
></H3
><P
>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.
</P
></DIV
><DIV
CLASS="REFSECT2"
><A
NAME="AEN108"
></A
><H3
><CODE
CLASS="SGMLTAG"
>rejectfont</CODE
></H3
><P
>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.
</P
></DIV
><DIV
CLASS="REFSECT2"
><A
NAME="AEN112"
></A
><H3
><CODE
CLASS="SGMLTAG"
>glob</CODE
></H3
><P
>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.
</P
></DIV
><DIV
CLASS="REFSECT2"
><A
NAME="AEN116"
></A
><H3
><CODE
CLASS="SGMLTAG"
>pattern</CODE
></H3
><P
>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.
</P
></DIV
><DIV
CLASS="REFSECT2"
><A
NAME="AEN120"
></A
><H3
><CODE
CLASS="SGMLTAG"
>patelt name="property"</CODE
></H3
><P
>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.
</P
></DIV
><DIV
CLASS="REFSECT2"
><A
NAME="AEN124"
></A
><H3
><CODE
CLASS="SGMLTAG"
>match target="pattern"</CODE
></H3
><P
>This element holds first a (possibly empty) list of <CODE
CLASS="SGMLTAG"
>test</CODE
> elements and then
a (possibly empty) list of <CODE
CLASS="SGMLTAG"
>edit</CODE
> 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.
</P
></DIV
><DIV
CLASS="REFSECT2"
><A
NAME="AEN130"
></A
><H3
><CODE
CLASS="SGMLTAG"
>test qual="any" name="property" target="default" compare="eq"</CODE
></H3
><P
>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", or
"more_eq". '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. When used in a &lt;match target="font"&gt; element,
the target= attribute in the &lt;test&gt; element selects between matching
the original pattern or the font. "default" selects whichever target the
outer &lt;match&gt; element has selected.
</P
></DIV
><DIV
CLASS="REFSECT2"
><A
NAME="AEN134"
></A
><H3
><CODE
CLASS="SGMLTAG"
>edit name="property" mode="assign" binding="weak"</CODE
></H3
><P
>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 <CODE
CLASS="SGMLTAG"
>test</CODE
> 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:
<PRE
CLASS="PROGRAMLISTING"
> 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
</PRE
>
</P
></DIV
><DIV
CLASS="REFSECT2"
><A
NAME="AEN140"
></A
><H3
><CODE
CLASS="SGMLTAG"
>int</CODE
>, <CODE
CLASS="SGMLTAG"
>double</CODE
>, <CODE
CLASS="SGMLTAG"
>string</CODE
>, <CODE
CLASS="SGMLTAG"
>bool</CODE
></H3
><P
>These elements hold a single value of the indicated type. <CODE
CLASS="SGMLTAG"
>bool</CODE
>
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).
</P
></DIV
><DIV
CLASS="REFSECT2"
><A
NAME="AEN148"
></A
><H3
><CODE
CLASS="SGMLTAG"
>matrix</CODE
></H3
><P
>This element holds the four <CODE
CLASS="SGMLTAG"
>double</CODE
> elements of an affine
transformation.
</P
></DIV
><DIV
CLASS="REFSECT2"
><A
NAME="AEN153"
></A
><H3
><CODE
CLASS="SGMLTAG"
>name</CODE
></H3
><P
>Holds a property name. Evaluates to the first value from the property of
the font, not the pattern.
</P
></DIV
><DIV
CLASS="REFSECT2"
><A
NAME="AEN157"
></A
><H3
><CODE
CLASS="SGMLTAG"
>const</CODE
></H3
><P
>Holds the name of a constant; these are always integers and serve as
symbolic names for common font values:
<PRE
CLASS="PROGRAMLISTING"
> Constant Property Value
-------------------------------------
thin weight 0
extralight weight 40
ultralight weight 40
light weight 50
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
hintnone hintstyle 0
hintslight hintstyle 1
hintmedium hintstyle 2
hintfull hintstyle 3
</PRE
>
</P
></DIV
><DIV
CLASS="REFSECT2"
><A
NAME="AEN162"
></A
><H3
><CODE
CLASS="SGMLTAG"
>or</CODE
>, <CODE
CLASS="SGMLTAG"
>and</CODE
>, <CODE
CLASS="SGMLTAG"
>plus</CODE
>, <CODE
CLASS="SGMLTAG"
>minus</CODE
>, <CODE
CLASS="SGMLTAG"
>times</CODE
>, <CODE
CLASS="SGMLTAG"
>divide</CODE
></H3
><P
>These elements perform the specified operation on a list of expression
elements. <CODE
CLASS="SGMLTAG"
>or</CODE
> and <CODE
CLASS="SGMLTAG"
>and</CODE
> are boolean, not bitwise.
</P
></DIV
><DIV
CLASS="REFSECT2"
><A
NAME="AEN173"
></A
><H3
><CODE
CLASS="SGMLTAG"
>eq</CODE
>, <CODE
CLASS="SGMLTAG"
>not_eq</CODE
>, <CODE
CLASS="SGMLTAG"
>less</CODE
>, <CODE
CLASS="SGMLTAG"
>less_eq</CODE
>, <CODE
CLASS="SGMLTAG"
>more</CODE
>, <CODE
CLASS="SGMLTAG"
>more_eq</CODE
></H3
><P
>These elements compare two values, producing a boolean result.
</P
></DIV
><DIV
CLASS="REFSECT2"
><A
NAME="AEN182"
></A
><H3
><CODE
CLASS="SGMLTAG"
>not</CODE
></H3
><P
>Inverts the boolean sense of its one expression element
</P
></DIV
><DIV
CLASS="REFSECT2"
><A
NAME="AEN186"
></A
><H3
><CODE
CLASS="SGMLTAG"
>if</CODE
></H3
><P
>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.
</P
></DIV
><DIV
CLASS="REFSECT2"
><A
NAME="AEN190"
></A
><H3
><CODE
CLASS="SGMLTAG"
>alias</CODE
></H3
><P
>Alias elements provide a shorthand notation for the set of common match
operations needed to substitute one font family for another. They contain a
<CODE
CLASS="SGMLTAG"
>family</CODE
> element followed by optional <CODE
CLASS="SGMLTAG"
>prefer</CODE
>, <CODE
CLASS="SGMLTAG"
>accept</CODE
> and <CODE
CLASS="SGMLTAG"
>default</CODE
>
elements. Fonts matching the <CODE
CLASS="SGMLTAG"
>family</CODE
> element are edited to prepend the
list of <CODE
CLASS="SGMLTAG"
>prefer</CODE
>ed families before the matching <CODE
CLASS="SGMLTAG"
>family</CODE
>, append the
<CODE
CLASS="SGMLTAG"
>accept</CODE
>able families after the matching <CODE
CLASS="SGMLTAG"
>family</CODE
> and append the <CODE
CLASS="SGMLTAG"
>default</CODE
>
families to the end of the family list.
</P
></DIV
><DIV
CLASS="REFSECT2"
><A
NAME="AEN204"
></A
><H3
><CODE
CLASS="SGMLTAG"
>family</CODE
></H3
><P
>Holds a single font family name
</P
></DIV
><DIV
CLASS="REFSECT2"
><A
NAME="AEN208"
></A
><H3
><CODE
CLASS="SGMLTAG"
>prefer</CODE
>, <CODE
CLASS="SGMLTAG"
>accept</CODE
>, <CODE
CLASS="SGMLTAG"
>default</CODE
></H3
><P
>These hold a list of <CODE
CLASS="SGMLTAG"
>family</CODE
> elements to be used by the <CODE
CLASS="SGMLTAG"
>alias</CODE
> element.
<CODE
CLASS="SGMLTAG"
>/article</CODE
>
</P
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN217"
></A
><H2
>EXAMPLE CONFIGURATION FILE</H2
><DIV
CLASS="REFSECT2"
><A
NAME="AEN219"
></A
><H3
>System configuration file</H3
><P
>This is an example of a system-wide configuration file
</P
><PRE
CLASS="PROGRAMLISTING"
>&lt;?xml version="1.0"?&gt;
&lt;!DOCTYPE fontconfig SYSTEM "fonts.dtd"&gt;
&lt;!-- /etc/fonts/fonts.conf file to configure system font access --&gt;
&lt;fontconfig&gt;
&lt;!--
Find fonts in these directories
--&gt;
&lt;dir&gt;/usr/share/fonts&lt;/dir&gt;
&lt;dir&gt;/usr/X11R6/lib/X11/fonts&lt;/dir&gt;
&lt;!--
Accept deprecated 'mono' alias, replacing it with 'monospace'
--&gt;
&lt;match target="pattern"&gt;
&lt;test qual="any" name="family"&gt;&lt;string&gt;mono&lt;/string&gt;&lt;/test&gt;
&lt;edit name="family" mode="assign"&gt;&lt;string&gt;monospace&lt;/string&gt;&lt;/edit&gt;
&lt;/match&gt;
&lt;!--
Names not including any well known alias are given 'sans'
--&gt;
&lt;match target="pattern"&gt;
&lt;test qual="all" name="family" mode="not_eq"&gt;sans&lt;/test&gt;
&lt;test qual="all" name="family" mode="not_eq"&gt;serif&lt;/test&gt;
&lt;test qual="all" name="family" mode="not_eq"&gt;monospace&lt;/test&gt;
&lt;edit name="family" mode="append_last"&gt;&lt;string&gt;sans&lt;/string&gt;&lt;/edit&gt;
&lt;/match&gt;
&lt;!--
Load per-user customization file, but don't complain
if it doesn't exist
--&gt;
&lt;include ignore_missing="yes"&gt;~/.fonts.conf&lt;/include&gt;
&lt;!--
Load local customization files, but don't complain
if there aren't any
--&gt;
&lt;include ignore_missing="yes"&gt;conf.d&lt;/include&gt;
&lt;include ignore_missing="yes"&gt;local.conf&lt;/include&gt;
&lt;!--
Alias well known font names to available TrueType fonts.
These substitute TrueType faces for similar Type1
faces to improve screen appearance.
--&gt;
&lt;alias&gt;
&lt;family&gt;Times&lt;/family&gt;
&lt;prefer&gt;&lt;family&gt;Times New Roman&lt;/family&gt;&lt;/prefer&gt;
&lt;default&gt;&lt;family&gt;serif&lt;/family&gt;&lt;/default&gt;
&lt;/alias&gt;
&lt;alias&gt;
&lt;family&gt;Helvetica&lt;/family&gt;
&lt;prefer&gt;&lt;family&gt;Arial&lt;/family&gt;&lt;/prefer&gt;
&lt;default&gt;&lt;family&gt;sans&lt;/family&gt;&lt;/default&gt;
&lt;/alias&gt;
&lt;alias&gt;
&lt;family&gt;Courier&lt;/family&gt;
&lt;prefer&gt;&lt;family&gt;Courier New&lt;/family&gt;&lt;/prefer&gt;
&lt;default&gt;&lt;family&gt;monospace&lt;/family&gt;&lt;/default&gt;
&lt;/alias&gt;
&lt;!--
Provide required aliases for standard names
Do these after the users configuration file so that
any aliases there are used preferentially
--&gt;
&lt;alias&gt;
&lt;family&gt;serif&lt;/family&gt;
&lt;prefer&gt;&lt;family&gt;Times New Roman&lt;/family&gt;&lt;/prefer&gt;
&lt;/alias&gt;
&lt;alias&gt;
&lt;family&gt;sans&lt;/family&gt;
&lt;prefer&gt;&lt;family&gt;Arial&lt;/family&gt;&lt;/prefer&gt;
&lt;/alias&gt;
&lt;alias&gt;
&lt;family&gt;monospace&lt;/family&gt;
&lt;prefer&gt;&lt;family&gt;Andale Mono&lt;/family&gt;&lt;/prefer&gt;
&lt;/alias&gt;
&lt;/fontconfig&gt;
</PRE
></DIV
><DIV
CLASS="REFSECT2"
><A
NAME="AEN223"
></A
><H3
>User configuration file</H3
><P
>This is an example of a per-user configuration file that lives in
~/.fonts.conf
</P
><PRE
CLASS="PROGRAMLISTING"
>&lt;?xml version="1.0"?&gt;
&lt;!DOCTYPE fontconfig SYSTEM "fonts.dtd"&gt;
&lt;!-- ~/.fonts.conf for per-user font configuration --&gt;
&lt;fontconfig&gt;
&lt;!--
Private font directory
--&gt;
&lt;dir&gt;~/.fonts&lt;/dir&gt;
&lt;!--
use rgb sub-pixel ordering to improve glyph appearance on
LCD screens. Changes affecting rendering, but not matching
should always use target="font".
--&gt;
&lt;match target="font"&gt;
&lt;edit name="rgba" mode="assign"&gt;&lt;const&gt;rgb&lt;/const&gt;&lt;/edit&gt;
&lt;/match&gt;
&lt;/fontconfig&gt;
</PRE
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN227"
></A
><H2
>Files</H2
><P
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>fonts.conf</I
></SPAN
>
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.
</P
><P
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>conf.d</I
></SPAN
>
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
&lt;include&gt; directive.
</P
><P
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>fonts.dtd</I
></SPAN
>
is a DTD that describes the format of the configuration files.
</P
><P
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>~/.fonts.conf</I
></SPAN
>
is the conventional location for per-user font configuration, although the
actual location is specified in the global fonts.conf file.
</P
><P
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
> ~/.fonts.cache-*</I
></SPAN
>
is the conventional repository of font information that isn't found in the
per-directory caches. This file is automatically maintained by fontconfig.
</P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN239"
></A
><H2
>See Also</H2
><P
>fc-cache(1), fc-match(1), fc-list(1)
</P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN242"
></A
><H2
>Version</H2
><P
>Fontconfig version 2.4.1
</P
></DIV
></BODY
></HTML
>
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