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5>FUNCTIONAL OVERVIEW</TITLE
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70><A
71NAME="AEN19"
72>FUNCTIONAL OVERVIEW</A
73></H1
74><P
75>Fontconfig contains two essential modules, the configuration module which
76builds an internal configuration from XML files and the matching module
77which accepts font patterns and returns the nearest matching font.
78  </P
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81><H2
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83><A
84NAME="AEN22"
85>FONT CONFIGURATION</A
86></H2
87><P
88>The configuration module consists of the FcConfig datatype, libexpat and
89FcConfigParse which walks over an XML tree and ammends a configuration with
90data found within.  From an external perspective, configuration of the
91library consists of generating a valid XML tree and feeding that to
92FcConfigParse.  The only other mechanism provided to applications for
93changing the running configuration is to add fonts and directories to the
94list of application-provided font files.  
95    </P
96><P
97>The intent is to make font configurations relatively static, and shared by
98as many applications as possible.  It is hoped that this will lead to more
99stable font selection when passing names from one application to another.
100XML was chosen as a configuration file format because it provides a format
101which is easy for external agents to edit while retaining the correct
102structure and syntax.
103    </P
104><P
105>Font configuration is separate from font matching; applications needing to
106do their own matching can access the available fonts from the library and
107perform private matching.  The intent is to permit applications to pick and
108choose appropriate functionality from the library instead of forcing them to
109choose between this library and a private configuration mechanism.  The hope
110is that this will ensure that configuration of fonts for all applications
111can be centralized in one place.  Centralizing font configuration will
112simplify and regularize font installation and customization.
113    </P
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117><H2
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119><A
120NAME="AEN27"
121>FONT PROPERTIES</A
122></H2
123><P
124>While font patterns may contain essentially any properties, there are some
125well known properties with associated types.  Fontconfig uses some of these
126properties for font matching and font completion.  Others are provided as a
127convenience for the applications rendering mechanism.
128    </P
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135><PRE
136CLASS="PROGRAMLISTING"
137>                 Property Definitions
138
139    Property       CPP Symbol           Type    Description
140    ----------------------------------------------------
141    family         FC_FAMILY            String  Font family names
142    familylang     FC_FAMILYLANG        String  Language cooresponding to
143                                                each family name
144    style          FC_STYLE             String  Font style. Overrides weight
145                                                and slant
146    stylelang      FC_STYLELANG         String  Language cooresponding 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 cooresponding 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
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
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
183    dpi            FC_DPI               Double  Target dots per inch
184    rgba           FC_RGBA              Int     unknown, rgb, bgr, vrgb,
185                                                vbgr, none - subpixel geometry
186    lcdfilter      FC_LCD_FILTER        Int     Type of LCD filter
187    minspace       FC_MINSPACE          Bool    Eliminate leading from line
188                                                spacing
189    charset        FC_CHARSET           CharSet Unicode chars encoded by
190                                                the font
191    lang           FC_LANG              LangSet Set of RFC-3066-style
192                                                languages this font supports
193    fontversion    FC_FONTVERSION       Int     Version number of the font
194    capability     FC_CAPABILITY        String  List of layout capabilities in
195                                                the font
196    embolden       FC_EMBOLDEN          Bool    Rasterizer should
197                                                synthetically embolden the font
198    </PRE
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