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72 >FUNCTIONAL OVERVIEW</A
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.
85 >FONT CONFIGURATION</A
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.
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.
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.
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.
136 CLASS="PROGRAMLISTING"
137 > Property Definitions
139 Property C Preprocessor Symbol Type Description
140 ----------------------------------------------------
141 family FC_FAMILY String Font family names
142 familylang FC_FAMILYLANG String Language corresponding to
144 style FC_STYLE String Font style. Overrides weight
146 stylelang FC_STYLELANG String Language corresponding to
148 fullname FC_FULLNAME String Font face full name where
149 different from family and
151 fullnamelang FC_FULLNAMELANG String Language corresponding to
153 slant FC_SLANT Int Italic, oblique or roman
154 weight FC_WEIGHT Int Light, medium, demibold,
156 size FC_SIZE Double Point size
157 width FC_WIDTH Int Condensed, normal or expanded
158 aspect FC_ASPECT Double Stretches glyphs horizontally
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
166 hinting FC_HINTING Bool Whether the rasterizer should
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
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
176 ftface FC_FT_FACE FT_Face Use the specified FreeType
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->pixel
183 color FC_COLOR Bool Whether any glyphs have color
184 dpi FC_DPI Double Target dots per inch
185 rgba FC_RGBA Int unknown, rgb, bgr, vrgb,
186 vbgr, none - subpixel geometry
187 lcdfilter FC_LCD_FILTER Int Type of LCD filter
188 minspace FC_MINSPACE Bool Eliminate leading from line
190 charset FC_CHARSET CharSet Unicode chars encoded by
192 lang FC_LANG LangSet Set of RFC-3066-style
193 languages this font supports
194 fontversion FC_FONTVERSION Int Version number of the font
195 capability FC_CAPABILITY String List of layout capabilities in
197 fontformat FC_FONTFORMAT String String name of the font format
198 embolden FC_EMBOLDEN Bool Rasterizer should
199 synthetically embolden the font
200 embeddedbitmap FC_EMBEDDED_BITMAP Bool Use the embedded bitmap instead
202 decorative FC_DECORATIVE Bool Whether the style is a decorative
204 fontfeatures FC_FONT_FEATURES String List of extra feature tags in
205 OpenType to be enabled
206 namelang FC_NAMELANG String Language name to be used for the
207 default value of familylang,
208 stylelang and fullnamelang
209 prgname FC_PRGNAME String Name of the running program
210 hash FC_HASH String SHA256 hash value of the font data
211 with "sha256:" prefix (deprecated)
212 postscriptname FC_POSTSCRIPT_NAME String Font name in PostScript
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