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      5 >FUNCTIONAL OVERVIEW</TITLE
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     70 ><A
     71 NAME="AEN19"
     72 >FUNCTIONAL OVERVIEW</A
     73 ></H1
     74 ><P
     75 >Fontconfig contains two essential modules, the configuration module which
     76 builds an internal configuration from XML files and the matching module
     77 which accepts font patterns and returns the nearest matching font.
     78   </P
     79 ><DIV
     80 CLASS="SECT2"
     81 ><H2
     82 CLASS="SECT2"
     83 ><A
     84 NAME="AEN22"
     85 >FONT CONFIGURATION</A
     86 ></H2
     87 ><P
     88 >The configuration module consists of the FcConfig datatype, libexpat and
     89 FcConfigParse which walks over an XML tree and amends a configuration with
     90 data found within.  From an external perspective, configuration of the
     91 library consists of generating a valid XML tree and feeding that to
     92 FcConfigParse.  The only other mechanism provided to applications for
     93 changing the running configuration is to add fonts and directories to the
     94 list of application-provided font files.  
     95     </P
     96 ><P
     97 >The intent is to make font configurations relatively static, and shared by
     98 as many applications as possible.  It is hoped that this will lead to more
     99 stable font selection when passing names from one application to another.
    100 XML was chosen as a configuration file format because it provides a format
    101 which is easy for external agents to edit while retaining the correct
    102 structure and syntax.
    103     </P
    104 ><P
    105 >Font configuration is separate from font matching; applications needing to
    106 do their own matching can access the available fonts from the library and
    107 perform private matching.  The intent is to permit applications to pick and
    108 choose appropriate functionality from the library instead of forcing them to
    109 choose between this library and a private configuration mechanism.  The hope
    110 is that this will ensure that configuration of fonts for all applications
    111 can be centralized in one place.  Centralizing font configuration will
    112 simplify and regularize font installation and customization.
    113     </P
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    116 CLASS="SECT2"
    117 ><H2
    118 CLASS="SECT2"
    119 ><A
    120 NAME="AEN27"
    121 >FONT PROPERTIES</A
    122 ></H2
    123 ><P
    124 >While font patterns may contain essentially any properties, there are some
    125 well known properties with associated types.  Fontconfig uses some of these
    126 properties for font matching and font completion.  Others are provided as a
    127 convenience for the application's rendering mechanism.
    128     </P
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    133 ><TR
    134 ><TD
    135 ><PRE
    136 CLASS="PROGRAMLISTING"
    137 >                 Property Definitions
    138 
    139     Property       C Preprocessor Symbol  Type    Description
    140     ----------------------------------------------------
    141     family         FC_FAMILY              String  Font family names
    142     familylang     FC_FAMILYLANG          String  Language corresponding to
    143                                                   each family name
    144     style          FC_STYLE               String  Font style. Overrides weight
    145                                                   and slant
    146     stylelang      FC_STYLELANG           String  Language corresponding to
    147                                                   each style name
    148     fullname       FC_FULLNAME            String  Font face full name where
    149                                                   different from family and
    150                                                   family + style
    151     fullnamelang   FC_FULLNAMELANG        String  Language corresponding to
    152                                                   each fullname
    153     slant          FC_SLANT               Int     Italic, oblique or roman
    154     weight         FC_WEIGHT              Int     Light, medium, demibold,
    155                                                   bold or black
    156     size           FC_SIZE                Double  Point size
    157     width          FC_WIDTH               Int     Condensed, normal or expanded
    158     aspect         FC_ASPECT              Double  Stretches glyphs horizontally
    159                                                   before hinting
    160     pixelsize      FC_PIXEL_SIZE          Double  Pixel size
    161     spacing        FC_SPACING             Int     Proportional, dual-width,
    162                                                   monospace or charcell
    163     foundry        FC_FOUNDRY             String  Font foundry name
    164     antialias      FC_ANTIALIAS           Bool    Whether glyphs can be
    165                                                   antialiased
    166     hinting        FC_HINTING             Bool    Whether the rasterizer should
    167                                                   use hinting
    168     hintstyle      FC_HINT_STYLE          Int     Automatic hinting style
    169     verticallayout FC_VERTICAL_LAYOUT     Bool    Use vertical layout
    170     autohint       FC_AUTOHINT            Bool    Use autohinter instead of
    171                                                   normal hinter
    172     globaladvance  FC_GLOBAL_ADVANCE      Bool    Use font global advance data (deprecated)
    173     file           FC_FILE                String  The filename holding the font
    174     index          FC_INDEX               Int     The index of the font within
    175                                                   the file
    176     ftface         FC_FT_FACE             FT_Face Use the specified FreeType
    177                                                   face object
    178     rasterizer     FC_RASTERIZER          String  Which rasterizer is in use (deprecated)
    179     outline        FC_OUTLINE             Bool    Whether the glyphs are outlines
    180     scalable       FC_SCALABLE            Bool    Whether glyphs can be scaled
    181     scale          FC_SCALE               Double  Scale factor for point-&#62;pixel
    182                                                   conversions (deprecated)
    183     symbol         FC_SYMBOL              Bool    Whether font uses MS symbol-font encoding
    184     color          FC_COLOR               Bool    Whether any glyphs have color
    185     dpi            FC_DPI                 Double  Target dots per inch
    186     rgba           FC_RGBA                Int     unknown, rgb, bgr, vrgb,
    187                                                   vbgr, none - subpixel geometry
    188     lcdfilter      FC_LCD_FILTER          Int     Type of LCD filter
    189     minspace       FC_MINSPACE            Bool    Eliminate leading from line
    190                                                   spacing
    191     charset        FC_CHARSET             CharSet Unicode chars encoded by
    192                                                   the font
    193     lang           FC_LANG                LangSet Set of RFC-3066-style
    194                                                   languages this font supports
    195     fontversion    FC_FONTVERSION         Int     Version number of the font
    196     capability     FC_CAPABILITY          String  List of layout capabilities in
    197                                                   the font
    198     fontformat     FC_FONTFORMAT          String  String name of the font format
    199     embolden       FC_EMBOLDEN            Bool    Rasterizer should
    200                                                   synthetically embolden the font
    201     embeddedbitmap FC_EMBEDDED_BITMAP     Bool    Use the embedded bitmap instead
    202                                                   of the outline
    203     decorative     FC_DECORATIVE          Bool    Whether the style is a decorative
    204                                                   variant
    205     fontfeatures   FC_FONT_FEATURES       String  List of extra feature tags in
    206                                                   OpenType to be enabled
    207     namelang       FC_NAMELANG            String  Language name to be used for the
    208                                                   default value of familylang,
    209                                                   stylelang and fullnamelang
    210     prgname        FC_PRGNAME             String  Name of the running program
    211     hash           FC_HASH                String  SHA256 hash value of the font data
    212                                                   with "sha256:" prefix (deprecated)
    213     postscriptname FC_POSTSCRIPT_NAME     String  Font name in PostScript
    214     </PRE
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