Provided by: fontconfig-config_2.8.0-3ubuntu9_all bug

NAME

       fonts.conf - Font configuration files

SYNOPSIS

          /etc/fonts/fonts.conf
          /etc/fonts/fonts.dtd
          /etc/fonts/conf.d
          ~/.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 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->pixel conversions
         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
         embolden        Bool    Rasterizer should synthetically embolden 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 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.

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
         OBJTYPES      4096    Display message when value typechecks fail

       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 "fonts.dtd">
            <fontconfig>
       ...
            </fontconfig>

   <FONTCONFIG>
       This is the top level element for a font configuration and  can  contain  <dir>,  <cache>,
       <include>, <match> and <alias> elements in any order.

   <DIR>
       This  element contains a directory name which will be scanned for font files to include in
       the set of available fonts.

   <CACHE>
       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-<version>'', where <version>  is  the  font  configuration  file  version
       number (currently 2).

   <INCLUDE IGNORE_MISSING= NO">"
       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.

   <CONFIG>
       This  element  provides  a  place  to  consolidate  additional  configuration information.
       <config> can contain <blank> and <rescan> elements in any order.

   <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.

   <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",  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 <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

   <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 the four <double> elements of an affine transformation.

   <NAME>
       Holds a property name. Evaluates to the first value from the property of the font, not the
       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
         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>
       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 "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></edit>
       </match>

       <!--
            Names not including any well known alias are given 'sans'
       -->
       <match target="pattern">
            <test qual="all" name="family" mode="not_eq">sans</test>
            <test qual="all" name="family" mode="not_eq">serif</test>
            <test qual="all" name="family" mode="not_eq">monospace</test>
            <edit name="family" mode="append_last"><string>sans</string></edit>
       </match>

       <!--
            Load per-user customization file, but don't complain
            if it doesn't exist
       -->
       <include ignore_missing="yes">~/.fonts.conf</include>

       <!--
            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>
       </fontconfig>

   USER CONFIGURATION FILE
       This is an example of a per-user configuration file that lives in ~/.fonts.conf

       <?xml version="1.0"?>
       <!DOCTYPE fontconfig SYSTEM "fonts.dtd">
       <!-- ~/.fonts.conf for per-user font configuration -->
       <fontconfig>

       <!--
            Private font directory
       -->
       <dir>~/.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>
       </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.

       ~/.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.

       ~/.fonts.conf is the conventional location for per-user font configuration,  although  the
       actual location is specified in the global fonts.conf file.

       ~/.fonts.cache-*  is  the  conventional repository of font information that isn't found in
       the per-directory caches. This file is automatically maintained by fontconfig.

SEE ALSO

       fc-cat(1), fc-cache(1), fc-list(1), fc-match(1), fc-query(1)

VERSION

       Fontconfig version 2.8.0

                                         18 November 2009                           FONTS-CONF(5)