unixdev.net


Switch to SpeakEasy.net DSL

The Modular Manual Browser

Home Page
Manual: (SunOS-5.10)
Page:
Section:
Apropos / Subsearch:
optional field

fonts.conf(4)                                                    fonts.conf(4)



NAME
       fonts.conf - Font configuration files

SYNOPSIS
          /etc/fonts/fonts.conf
          /etc/fonts/fonts.dtd
          ~/.fonts.conf

DESCRIPTION
       Fontconfig is a library designed to provide system-wide font configura-
       tion, 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 ammends a configura-
       tion  with data found within.  From an external perspective, configura-
       tion of the library consists of generating a valid XML tree and feeding
       that  to  FcConfigParse.  The only other mechanism provided to applica-
       tions for changing the running configuration is to add fonts and direc-
       tories 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 applica-
       tions  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 con-
       figuration 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 name
         style           String  Font style. Overrides weight and slant
         slant           Int     Italic, oblique or roman
         weight          Int     Light, medium, demibold, bold or black
         size            Double  Point size
         aspect          Double  Stretches glyphs horizontally before hinting
         pixelsize       Double  Pixel size
         spacing         Int     Proportional, monospace or charcell
         foundry         String  Font foundry name
         antialias       Bool    Whether glyphs can be antialiased
         hinting         Bool    Whether the rasterizer should use hinting
         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
         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


   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 con-
       sists  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 val-
       ues 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,  pixel-
       size,  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  proper-
       ties  found  in the pattern but not found in the font itself; this per-
       mits 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  pat-
       tern.  This modified pattern is returned to the application.

       The  return value contains sufficient information to locate and raster-
       ize 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


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 ISO639 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.

CONFIGURATION FILE FORMAT
       Configuration  files for fontconfig are stored in XML format; this for-
       mat 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>


   <&lt;FONTCONFIG>&gt;
       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 infor-
       mation.   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 1).

   INCLUDE IGNORE_MISSING= NO""
       This element contains the name of  an  additional  configuration  file.
       When  the  XML  datatype is traversed by FcConfigParse, the contents of
       the file will also be incorporated into the  configuration  by  passing
       the  filename  to  FcConfigLoadAndParse.  If 'ignore_missing' is set to
       "yes" instead of the default "no", a missing file will elicit no  warn-
       ing message from the library.

   CONFIG
       This  element  provides a place to consolodate 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 ele-
       ment.  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  inter-
       val passes.

   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.

   TEST QUAL= ANY" NAME="PROPERTY" COMPARE="EQ""
       This element contains a single value which is compared with the pattern
       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.

   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. '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  ele-
       ments hold either true or false.  An important limitation exists in the
       parsing of floating point numbers -- fontconfig requires that the  man-
       tissa 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 transforma-
       tion.

   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
         -------------------------------------
         light           weight          0
         medium          weight          100
         demibold        weight          180
         bold            weight          200
         black           weight          210
         roman           slant           0
         italic          slant           100
         oblique         slant           110
         proportional    spacing         0
         mono            spacing         100
         charcell        spacing         110
         unknown         rgba            0
         rgb             rgba            1
         bgr             rgba            2
         vrgb            rgba            3
         vbgr            rgba            4
         none            rgba            5


   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 con-
       tain  a  family element followed by optional prefer, accept and default
       elements.  Fonts matching the family element are edited to prepend  the
       list  of  prefered  families  before  the  matching  family, append the
       acceptable familys 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.
       /article

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/X11R6/lib/X11/fonts/truetype</dir>
       <dir>/usr/X11R6/lib/X11/fonts/Type1</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>

       <!--
            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>Verdana</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>Verdana</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>~/misc/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.

       fonts.dtd is a DTD that  describes  the  format  of  the  configuration
       files.

       ~/.fonts.conf is the conventional location for per-user font configura-
       tion,  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  automati-
       cally maintained by fontconfig.

VERSION
       Fontconfig version 2.2.3

ATTRIBUTES
       See attributes(5) for descriptions of the following attributes:


       box; cbp-1 | cbp-1 l | l .  ATTRIBUTE TYPE ATTRIBUTE VALUE = Availabil-
       ity   SUNWfontconfig-root Interface Stability External



                                 30 June 2004                    fonts.conf(4)