fontconfig-user.sgml revision a4e54154
1<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook V3.1//EN" [ 2<!ENTITY version SYSTEM "version.sgml"> 3<!ENTITY confdir SYSTEM "confdir.sgml"> 4]> 5<!-- 6 Copyright © 2003 Keith Packard 7 8 Permission to use, copy, modify, distribute, and sell this software and its 9 documentation for any purpose is hereby granted without fee, provided that 10 the above copyright notice appear in all copies and that both that 11 copyright notice and this permission notice appear in supporting 12 documentation, and that the name of the author(s) not be used in 13 advertising or publicity pertaining to distribution of the software without 14 specific, written prior permission. The authors make no 15 representations about the suitability of this software for any purpose. It 16 is provided "as is" without express or implied warranty. 17 18 THE AUTHOR(S) DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, 19 INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO 20 EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY SPECIAL, INDIRECT OR 21 CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, 22 DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER 23 TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR 24 PERFORMANCE OF THIS SOFTWARE. 25--> 26<refentry> 27<refmeta> 28 <refentrytitle>fonts-conf</refentrytitle> 29 <manvolnum>5</manvolnum> 30</refmeta> 31<refnamediv> 32 <refname>fonts.conf</refname> 33 <refpurpose>Font configuration files</refpurpose> 34</refnamediv> 35<refsynopsisdiv> 36<synopsis> 37 &confdir;/fonts.conf 38 &confdir;/fonts.dtd 39 &confdir;/conf.d 40 $XDG_CONFIG_HOME/fontconfig/conf.d 41 $XDG_CONFIG_HOME/fontconfig/fonts.conf 42 ~/.fonts.conf.d 43 ~/.fonts.conf 44</synopsis> 45</refsynopsisdiv> 46<refsect1><title>Description</title> 47 <para> 48Fontconfig is a library designed to provide system-wide font configuration, 49customization and application access. 50 </para> 51</refsect1> 52<refsect1><title>Functional Overview</title> 53 <para> 54Fontconfig contains two essential modules, the configuration module which 55builds an internal configuration from XML files and the matching module 56which accepts font patterns and returns the nearest matching font. 57 </para> 58 <refsect2><title>Font Configuration</title> 59 <para> 60The configuration module consists of the FcConfig datatype, libexpat and 61FcConfigParse which walks over an XML tree and amends a configuration with 62data found within. From an external perspective, configuration of the 63library consists of generating a valid XML tree and feeding that to 64FcConfigParse. The only other mechanism provided to applications for 65changing the running configuration is to add fonts and directories to the 66list of application-provided font files. 67 </para><para> 68The intent is to make font configurations relatively static, and shared by 69as many applications as possible. It is hoped that this will lead to more 70stable font selection when passing names from one application to another. 71XML was chosen as a configuration file format because it provides a format 72which is easy for external agents to edit while retaining the correct 73structure and syntax. 74 </para><para> 75Font configuration is separate from font matching; applications needing to 76do their own matching can access the available fonts from the library and 77perform private matching. The intent is to permit applications to pick and 78choose appropriate functionality from the library instead of forcing them to 79choose between this library and a private configuration mechanism. The hope 80is that this will ensure that configuration of fonts for all applications 81can be centralized in one place. Centralizing font configuration will 82simplify and regularize font installation and customization. 83 </para> 84 </refsect2> 85 <refsect2> 86 <title>Font Properties</title> 87 <para> 88While font patterns may contain essentially any properties, there are some 89well known properties with associated types. Fontconfig uses some of these 90properties for font matching and font completion. Others are provided as a 91convenience for the applications' rendering mechanism. 92 </para> 93 <programlisting> 94 Property Type Description 95 -------------------------------------------------------------- 96 family String Font family names 97 familylang String Languages corresponding to each family 98 style String Font style. Overrides weight and slant 99 stylelang String Languages corresponding to each style 100 fullname String Font full names (often includes style) 101 fullnamelang String Languages corresponding to each fullname 102 slant Int Italic, oblique or roman 103 weight Int Light, medium, demibold, bold or black 104 size Double Point size 105 width Int Condensed, normal or expanded 106 aspect Double Stretches glyphs horizontally before hinting 107 pixelsize Double Pixel size 108 spacing Int Proportional, dual-width, monospace or charcell 109 foundry String Font foundry name 110 antialias Bool Whether glyphs can be antialiased 111 hinting Bool Whether the rasterizer should use hinting 112 hintstyle Int Automatic hinting style 113 verticallayout Bool Use vertical layout 114 autohint Bool Use autohinter instead of normal hinter 115 globaladvance Bool Use font global advance data (deprecated) 116 file String The filename holding the font 117 index Int The index of the font within the file 118 ftface FT_Face Use the specified FreeType face object 119 rasterizer String Which rasterizer is in use (deprecated) 120 outline Bool Whether the glyphs are outlines 121 scalable Bool Whether glyphs can be scaled 122 color Bool Whether any glyphs have color 123 scale Double Scale factor for point->pixel conversions (deprecated) 124 dpi Double Target dots per inch 125 rgba Int unknown, rgb, bgr, vrgb, vbgr, 126 none - subpixel geometry 127 lcdfilter Int Type of LCD filter 128 minspace Bool Eliminate leading from line spacing 129 charset CharSet Unicode chars encoded by the font 130 lang String List of RFC-3066-style languages this 131 font supports 132 fontversion Int Version number of the font 133 capability String List of layout capabilities in the font 134 fontformat String String name of the font format 135 embolden Bool Rasterizer should synthetically embolden the font 136 embeddedbitmap Bool Use the embedded bitmap instead of the outline 137 decorative Bool Whether the style is a decorative variant 138 fontfeatures String List of the feature tags in OpenType to be enabled 139 namelang String Language name to be used for the default value of 140 familylang, stylelang, and fullnamelang 141 prgname String String Name of the running program 142 postscriptname String Font family name in PostScript 143 fonthashint Bool Whether the font has hinting 144 order Int Order number of the font 145 </programlisting> 146 </refsect2> 147 <refsect2> 148 <title>Font Matching</title> 149 <para> 150Fontconfig performs matching by measuring the distance from a provided 151pattern to all of the available fonts in the system. The closest matching 152font is selected. This ensures that a font will always be returned, but 153doesn't ensure that it is anything like the requested pattern. 154 </para><para> 155Font matching starts with an application constructed pattern. The desired 156attributes of the resulting font are collected together in a pattern. Each 157property of the pattern can contain one or more values; these are listed in 158priority order; matches earlier in the list are considered "closer" than 159matches later in the list. 160 </para><para> 161The initial pattern is modified by applying the list of editing instructions 162specific to patterns found in the configuration; each consists of a match 163predicate and a set of editing operations. They are executed in the order 164they appeared in the configuration. Each match causes the associated 165sequence of editing operations to be applied. 166 </para><para> 167After the pattern has been edited, a sequence of default substitutions are 168performed to canonicalize the set of available properties; this avoids the 169need for the lower layers to constantly provide default values for various 170font properties during rendering. 171 </para><para> 172The canonical font pattern is finally matched against all available fonts. 173The distance from the pattern to the font is measured for each of several 174properties: foundry, charset, family, lang, spacing, pixelsize, style, 175slant, weight, antialias, rasterizer and outline. This list is in priority 176order -- results of comparing earlier elements of this list weigh more 177heavily than later elements. 178 </para><para> 179There is one special case to this rule; family names are split into two 180bindings; strong and weak. Strong family names are given greater precedence 181in the match than lang elements while weak family names are given lower 182precedence than lang elements. This permits the document language to drive 183font selection when any document specified font is unavailable. 184 </para><para> 185The pattern representing that font is augmented to include any properties 186found in the pattern but not found in the font itself; this permits the 187application to pass rendering instructions or any other data through the 188matching system. Finally, the list of editing instructions specific to 189fonts found in the configuration are applied to the pattern. This modified 190pattern is returned to the application. 191 </para><para> 192The return value contains sufficient information to locate and rasterize the 193font, including the file name, pixel size and other rendering data. As 194none of the information involved pertains to the FreeType library, 195applications are free to use any rasterization engine or even to take 196the identified font file and access it directly. 197 </para><para> 198The match/edit sequences in the configuration are performed in two passes 199because there are essentially two different operations necessary -- the 200first is to modify how fonts are selected; aliasing families and adding 201suitable defaults. The second is to modify how the selected fonts are 202rasterized. Those must apply to the selected font, not the original pattern 203as false matches will often occur. 204 </para> 205 </refsect2> 206 <refsect2><title>Font Names</title> 207 <para> 208Fontconfig provides a textual representation for patterns that the library 209can both accept and generate. The representation is in three parts, first a 210list of family names, second a list of point sizes and finally a list of 211additional properties: 212 </para> 213 <programlisting> 214 <families>-<point sizes>:<name1>=<values1>:<name2>=<values2>... 215 </programlisting> 216 <para> 217Values in a list are separated with commas. The name needn't include either 218families or point sizes; they can be elided. In addition, there are 219symbolic constants that simultaneously indicate both a name and a value. 220Here are some examples: 221 </para> 222 <programlisting> 223 Name Meaning 224 ---------------------------------------------------------- 225 Times-12 12 point Times Roman 226 Times-12:bold 12 point Times Bold 227 Courier:italic Courier Italic in the default size 228 Monospace:matrix=1 .1 0 1 The users preferred monospace font 229 with artificial obliquing 230 </programlisting> 231 <para> 232The '\', '-', ':' and ',' characters in family names must be preceded by a 233'\' character to avoid having them misinterpreted. Similarly, values 234containing '\', '=', '_', ':' and ',' must also have them preceded by a 235'\' character. The '\' characters are stripped out of the family name and 236values as the font name is read. 237 </para> 238 </refsect2> 239</refsect1> 240<refsect1 id="debug"><title>Debugging Applications</title> 241 <para> 242To help diagnose font and applications problems, fontconfig is built with a 243large amount of internal debugging left enabled. It is controlled by means 244of the FC_DEBUG environment variable. The value of this variable is 245interpreted as a number, and each bit within that value controls different 246debugging messages. 247 </para> 248 <programlisting> 249 Name Value Meaning 250 --------------------------------------------------------- 251 MATCH 1 Brief information about font matching 252 MATCHV 2 Extensive font matching information 253 EDIT 4 Monitor match/test/edit execution 254 FONTSET 8 Track loading of font information at startup 255 CACHE 16 Watch cache files being written 256 CACHEV 32 Extensive cache file writing information 257 PARSE 64 (no longer in use) 258 SCAN 128 Watch font files being scanned to build caches 259 SCANV 256 Verbose font file scanning information 260 MEMORY 512 Monitor fontconfig memory usage 261 CONFIG 1024 Monitor which config files are loaded 262 LANGSET 2048 Dump char sets used to construct lang values 263 MATCH2 4096 Display font-matching transformation in patterns 264 </programlisting> 265 <para> 266Add the value of the desired debug levels together and assign that (in 267base 10) to the FC_DEBUG environment variable before running the 268application. Output from these statements is sent to stdout. 269 </para> 270</refsect1> 271<refsect1><title>Lang Tags</title> 272 <para> 273Each font in the database contains a list of languages it supports. This is 274computed by comparing the Unicode coverage of the font with the orthography 275of each language. Languages are tagged using an RFC-3066 compatible naming 276and occur in two parts -- the ISO 639 language tag followed a hyphen and then 277by the ISO 3166 country code. The hyphen and country code may be elided. 278 </para><para> 279Fontconfig has orthographies for several languages built into the library. 280No provision has been made for adding new ones aside from rebuilding the 281library. It currently supports 122 of the 139 languages named in ISO 639-1, 282141 of the languages with two-letter codes from ISO 639-2 and another 30 283languages with only three-letter codes. Languages with both two and three 284letter codes are provided with only the two letter code. 285 </para><para> 286For languages used in multiple territories with radically different 287character sets, fontconfig includes per-territory orthographies. This 288includes Azerbaijani, Kurdish, Pashto, Tigrinya and Chinese. 289 </para> 290</refsect1> 291<refsect1><title>Configuration File Format</title> 292 <para> 293Configuration files for fontconfig are stored in XML format; this 294format makes external configuration tools easier to write and ensures that 295they will generate syntactically correct configuration files. As XML 296files are plain text, they can also be manipulated by the expert user using 297a text editor. 298 </para><para> 299The fontconfig document type definition resides in the external entity 300"fonts.dtd"; this is normally stored in the default font configuration 301directory (&confdir;). Each configuration file should contain the 302following structure: 303 <programlisting> 304 <?xml version="1.0"?> 305 <!DOCTYPE fontconfig SYSTEM "urn:fontconfig:fonts.dtd"> 306 <fontconfig> 307 ... 308 </fontconfig> 309 </programlisting> 310 </para> 311<refsect2><title><literal><fontconfig></literal></title><para> 312This is the top level element for a font configuration and can contain 313<literal><dir></literal>, <literal><cachedir></literal>, <literal><include></literal>, <literal><match></literal> and <literal><alias></literal> elements in any order. 314 </para></refsect2> 315 <refsect2><title><literal><dir prefix="default" salt=""></literal></title><para> 316This element contains a directory name which will be scanned for font files 317to include in the set of available fonts. 318 </para><para> 319If 'prefix' is set to "default" or "cwd", the current working directory will be added as the path prefix prior to the value. If 'prefix' is set to "xdg", the value in the XDG_DATA_HOME environment variable will be added as the path prefix. please see XDG Base Directory Specification for more details. If 'prefix' is set to "relative", the path of current file will be added prior to the value. 320 </para><para> 321'salt' property affects to determine cache filename. this is useful for example when having different fonts sets on same path at container and share fonts from host on different font path. 322 </para></refsect2> 323 <refsect2><title><literal><cachedir prefix="default"></literal></title><para> 324This element contains a directory name that is supposed to be stored or read 325the cache of font information. If multiple elements are specified in 326the configuration file, the directory that can be accessed first in the list 327will be used to store the cache files. If it starts with '~', it refers to 328a directory in the users home directory. If 'prefix' is set to "xdg", the value in the XDG_CACHE_HOME environment variable will be added as the path prefix. please see XDG Base Directory Specification for more details. 329The default directory is ``$XDG_CACHE_HOME/fontconfig'' and it contains the cache files 330named ``<literal><hash value></literal>-<literal><architecture></literal>.cache-<literal><version></literal>'', 331where <literal><version></literal> is the fontconfig cache file 332version number (currently 7). 333 </para></refsect2> 334 <refsect2><title><literal><include ignore_missing="no" prefix="default"></literal></title><para> 335This element contains the name of an additional configuration file or 336directory. If a directory, every file within that directory starting with an 337ASCII digit (U+0030 - U+0039) and ending with the string ``.conf'' will be processed in sorted order. When 338the XML datatype is traversed by FcConfigParse, the contents of the file(s) 339will also be incorporated into the configuration by passing the filename(s) to 340FcConfigLoadAndParse. If 'ignore_missing' is set to "yes" instead of the 341default "no", a missing file or directory will elicit no warning message from 342the library. If 'prefix' is set to "xdg", the value in the XDG_CONFIG_HOME environment variable will be added as the path prefix. please see XDG Base Directory Specification for more details. 343 </para></refsect2> 344 <refsect2><title><literal><config></literal></title><para> 345This element provides a place to consolidate additional configuration 346information. <literal><config></literal> can contain <literal><blank></literal> and <literal><rescan></literal> elements in any 347order. 348 </para></refsect2> 349 <refsect2><title><literal><description domain="fontconfig-conf"></literal></title><para> 350This element is supposed to hold strings which describe what a config is used for. 351This string can be translated through gettext. 'domain' needs to be set the proper name to apply then. 352fontconfig will tries to retrieve translations with 'domain' from gettext. 353 </para></refsect2> 354 <refsect2><title><literal><blank></literal></title><para> 355Fonts often include "broken" glyphs which appear in the encoding but are 356drawn as blanks on the screen. Within the <literal><blank></literal> element, place each 357Unicode characters which is supposed to be blank in an <literal><int></literal> element. 358Characters outside of this set which are drawn as blank will be elided from 359the set of characters supported by the font. 360 </para></refsect2> 361 <refsect2><title><literal><remap-dir prefix="default" as-path="" salt=""></literal></title><para> 362This element contains a directory name where will be mapped 363as the path 'as-path' in cached information. 364This is useful if the directory name is an alias 365(via a bind mount or symlink) to another directory in the system for 366which cached font information is likely to exist. 367 </para><para> 368'salt' property affects to determine cache filename as same as <literal><dir></literal> element. 369 </para></refsect2> 370 <refsect2><title><literal><reset-dirs /></literal></title><para> 371This element removes all of fonts directories where added by <literal><dir></literal> elements. 372This is useful to override fonts directories from system to own fonts directories only. 373 </para></refsect2> 374 <refsect2><title><literal><rescan></literal></title><para> 375The <literal><rescan></literal> element holds an <literal><int></literal> element which indicates the default 376interval between automatic checks for font configuration changes. 377Fontconfig will validate all of the configuration files and directories and 378automatically rebuild the internal datastructures when this interval passes. 379 </para></refsect2> 380 <refsect2><title><literal><selectfont></literal></title><para> 381This element is used to black/white list fonts from being listed or matched 382against. It holds acceptfont and rejectfont elements. 383 </para></refsect2> 384 <refsect2><title><literal><acceptfont></literal></title><para> 385Fonts matched by an acceptfont element are "whitelisted"; such fonts are 386explicitly included in the set of fonts used to resolve list and match 387requests; including them in this list protects them from being "blacklisted" 388by a rejectfont element. Acceptfont elements include glob and pattern 389elements which are used to match fonts. 390 </para></refsect2> 391 <refsect2><title><literal><rejectfont></literal></title><para> 392Fonts matched by an rejectfont element are "blacklisted"; such fonts are 393excluded from the set of fonts used to resolve list and match requests as if 394they didn't exist in the system. Rejectfont elements include glob and 395pattern elements which are used to match fonts. 396 </para></refsect2> 397 <refsect2><title><literal><glob></literal></title><para> 398Glob elements hold shell-style filename matching patterns (including ? and 399*) which match fonts based on their complete pathnames. This can be used to 400exclude a set of directories (/usr/share/fonts/uglyfont*), or particular 401font file types (*.pcf.gz), but the latter mechanism relies rather heavily 402on filenaming conventions which can't be relied upon. Note that globs 403only apply to directories, not to individual fonts. 404 </para></refsect2> 405 <refsect2><title><literal><pattern></literal></title><para> 406Pattern elements perform list-style matching on incoming fonts; that is, 407they hold a list of elements and associated values. If all of those 408elements have a matching value, then the pattern matches the font. This can 409be used to select fonts based on attributes of the font (scalable, bold, 410etc), which is a more reliable mechanism than using file extensions. 411Pattern elements include patelt elements. 412 </para></refsect2> 413 <refsect2><title><literal><patelt name="property"></literal></title><para> 414Patelt elements hold a single pattern element and list of values. They must 415have a 'name' attribute which indicates the pattern element name. Patelt 416elements include int, double, string, matrix, bool, charset and const 417elements. 418 </para></refsect2> 419 <refsect2><title><literal><match target="pattern"></literal></title><para> 420This element holds first a (possibly empty) list of <literal><test></literal> elements and then 421a (possibly empty) list of <literal><edit></literal> elements. Patterns which match all of the 422tests are subjected to all the edits. If 'target' is set to "font" instead 423of the default "pattern", then this element applies to the font name 424resulting from a match rather than a font pattern to be matched. If 'target' 425is set to "scan", then this element applies when the font is scanned to 426build the fontconfig database. 427 </para></refsect2> 428 <refsect2><title><literal><test qual="any" name="property" target="default" compare="eq"></literal></title><para> 429This element contains a single value which is compared with the target 430('pattern', 'font', 'scan' or 'default') property "property" (substitute any of the property names seen 431above). 'compare' can be one of "eq", "not_eq", "less", "less_eq", "more", "more_eq", "contains" or 432"not_contains". 'qual' may either be the default, "any", in which case the match 433succeeds if any value associated with the property matches the test value, or 434"all", in which case all of the values associated with the property must 435match the test value. 'ignore-blanks' takes a boolean value. if 'ignore-blanks' is set "true", any blanks in the string will be ignored on its comparison. this takes effects only when compare="eq" or compare="not_eq". 436When used in a <match target="font"> element, 437the target= attribute in the <test> element selects between matching 438the original pattern or the font. "default" selects whichever target the 439outer <match> element has selected. 440 </para></refsect2> 441 <refsect2><title><literal><edit name="property" mode="assign" binding="weak"></literal></title><para> 442This element contains a list of expression elements (any of the value or 443operator elements). The expression elements are evaluated at run-time and 444modify the property "property". The modification depends on whether 445"property" was matched by one of the associated <literal><test></literal> elements, if so, the 446modification may affect the first matched value. Any values inserted into 447the property are given the indicated binding ("strong", "weak" or "same") 448with "same" binding using the value from the matched pattern element. 449'mode' is one of: 450 <programlisting> 451 Mode With Match Without Match 452 --------------------------------------------------------------------- 453 "assign" Replace matching value Replace all values 454 "assign_replace" Replace all values Replace all values 455 "prepend" Insert before matching Insert at head of list 456 "prepend_first" Insert at head of list Insert at head of list 457 "append" Append after matching Append at end of list 458 "append_last" Append at end of list Append at end of list 459 "delete" Delete matching value Delete all values 460 "delete_all" Delete all values Delete all values 461 </programlisting> 462 </para></refsect2> 463 <refsect2><title><literal><int></literal>, <literal><double></literal>, <literal><string></literal>, <literal><bool></literal></title><para> 464These elements hold a single value of the indicated type. <literal><bool></literal> 465elements hold either true or false. An important limitation exists in 466the parsing of floating point numbers -- fontconfig requires that 467the mantissa start with a digit, not a decimal point, so insert a leading 468zero for purely fractional values (e.g. use 0.5 instead of .5 and -0.5 469instead of -.5). 470 </para></refsect2> 471 <refsect2><title><literal><matrix></literal></title><para> 472This element holds four numerical expressions of an affine transformation. 473At their simplest these will be four <literal><double></literal> elements 474but they can also be more involved expressions. 475 </para></refsect2> 476 <refsect2><title><literal><range></literal></title><para> 477This element holds the two <literal><int></literal> elements of a range 478representation. 479 </para></refsect2> 480 <refsect2><title><literal><charset></literal></title><para> 481This element holds at least one <literal><int></literal> element of 482an Unicode code point or more. 483 </para></refsect2> 484 <refsect2><title><literal><langset></literal></title><para> 485This element holds at least one <literal><string></literal> element of 486a RFC-3066-style languages or more. 487 </para></refsect2> 488 <refsect2><title><literal><name></literal></title><para> 489Holds a property name. Evaluates to the first value from the property of 490the pattern. If the 'target' attribute is not present, it will default to 491'default', in which case the property is returned from the font pattern 492during a target="font" match, and to the pattern during a target="pattern" 493match. The attribute can also take the values 'font' or 'pattern' to 494explicitly choose which pattern to use. It is an error to use a target 495of 'font' in a match that has target="pattern". 496 </para></refsect2> 497 <refsect2><title><literal><const></literal></title><para> 498Holds the name of a constant; these are always integers and serve as 499symbolic names for common font values: 500 <programlisting> 501 Constant Property Value 502 ------------------------------------- 503 thin weight 0 504 extralight weight 40 505 ultralight weight 40 506 light weight 50 507 demilight weight 55 508 semilight weight 55 509 book weight 75 510 regular weight 80 511 normal weight 80 512 medium weight 100 513 demibold weight 180 514 semibold weight 180 515 bold weight 200 516 extrabold weight 205 517 black weight 210 518 heavy weight 210 519 roman slant 0 520 italic slant 100 521 oblique slant 110 522 ultracondensed width 50 523 extracondensed width 63 524 condensed width 75 525 semicondensed width 87 526 normal width 100 527 semiexpanded width 113 528 expanded width 125 529 extraexpanded width 150 530 ultraexpanded width 200 531 proportional spacing 0 532 dual spacing 90 533 mono spacing 100 534 charcell spacing 110 535 unknown rgba 0 536 rgb rgba 1 537 bgr rgba 2 538 vrgb rgba 3 539 vbgr rgba 4 540 none rgba 5 541 lcdnone lcdfilter 0 542 lcddefault lcdfilter 1 543 lcdlight lcdfilter 2 544 lcdlegacy lcdfilter 3 545 hintnone hintstyle 0 546 hintslight hintstyle 1 547 hintmedium hintstyle 2 548 hintfull hintstyle 3 549 </programlisting> 550 </para> 551 </refsect2> 552 <refsect2> 553 <title><literal><or></literal>, <literal><and></literal>, <literal><plus></literal>, <literal><minus></literal>, <literal><times></literal>, <literal><divide></literal></title> 554 <para> 555These elements perform the specified operation on a list of expression 556elements. <literal><or></literal> and <literal><and></literal> are boolean, not bitwise. 557 </para> 558 </refsect2> 559 <refsect2> 560 <title><literal><eq></literal>, <literal><not_eq></literal>, <literal><less></literal>, <literal><less_eq></literal>, <literal><more></literal>, <literal><more_eq></literal>, <literal><contains></literal>, <literal><not_contains</literal></title> 561 <para> 562These elements compare two values, producing a boolean result. 563 </para></refsect2> 564 <refsect2><title><literal><not></literal></title><para> 565Inverts the boolean sense of its one expression element 566 </para></refsect2> 567 <refsect2><title><literal><if></literal></title><para> 568This element takes three expression elements; if the value of the first is 569true, it produces the value of the second, otherwise it produces the value 570of the third. 571 </para></refsect2> 572 <refsect2><title><literal><alias></literal></title><para> 573Alias elements provide a shorthand notation for the set of common match 574operations needed to substitute one font family for another. They contain a 575<literal><family></literal> element followed by optional <literal><prefer></literal>, <literal><accept></literal> and <literal><default></literal> 576elements. Fonts matching the <literal><family></literal> element are edited to prepend the 577list of <literal><prefer></literal>ed families before the matching <literal><family></literal>, append the 578<literal><accept></literal>able families after the matching <literal><family></literal> and append the <literal><default></literal> 579families to the end of the family list. 580 </para></refsect2> 581 <refsect2><title><literal><family></literal></title><para> 582Holds a single font family name 583 </para></refsect2> 584 <refsect2><title><literal><prefer></literal>, <literal><accept></literal>, <literal><default></literal></title><para> 585These hold a list of <literal><family></literal> elements to be used by the <literal><alias></literal> element. 586 </para></refsect2> 587</refsect1> 588<refsect1><title>EXAMPLE CONFIGURATION FILE</title> 589 <refsect2><title>System configuration file</title> 590 <para> 591This is an example of a system-wide configuration file 592 </para> 593 <programlisting> 594<?xml version="1.0"?> 595<!DOCTYPE fontconfig SYSTEM "urn:fontconfig:fonts.dtd"> 596<!-- &confdir;/fonts.conf file to configure system font access --> 597<fontconfig> 598<!-- 599 Find fonts in these directories 600--> 601<dir>/usr/share/fonts</dir> 602<dir>/usr/X11R6/lib/X11/fonts</dir> 603 604<!-- 605 Accept deprecated 'mono' alias, replacing it with 'monospace' 606--> 607<match target="pattern"> 608 <test qual="any" name="family"><string>mono</string></test> 609 <edit name="family" mode="assign"><string>monospace</string></edit> 610</match> 611 612<!-- 613 Names not including any well known alias are given 'sans-serif' 614--> 615<match target="pattern"> 616 <test qual="all" name="family" compare="not_eq"><string>sans-serif</string></test> 617 <test qual="all" name="family" compare="not_eq"><string>serif</string></test> 618 <test qual="all" name="family" compare="not_eq"><string>monospace</string></test> 619 <edit name="family" mode="append_last"><string>sans-serif</string></edit> 620</match> 621 622<!-- 623 Load per-user customization file, but don't complain 624 if it doesn't exist 625--> 626<include ignore_missing="yes" prefix="xdg">fontconfig/fonts.conf</include> 627 628<!-- 629 Load local customization files, but don't complain 630 if there aren't any 631--> 632<include ignore_missing="yes">conf.d</include> 633<include ignore_missing="yes">local.conf</include> 634 635<!-- 636 Alias well known font names to available TrueType fonts. 637 These substitute TrueType faces for similar Type1 638 faces to improve screen appearance. 639--> 640<alias> 641 <family>Times</family> 642 <prefer><family>Times New Roman</family></prefer> 643 <default><family>serif</family></default> 644</alias> 645<alias> 646 <family>Helvetica</family> 647 <prefer><family>Arial</family></prefer> 648 <default><family>sans</family></default> 649</alias> 650<alias> 651 <family>Courier</family> 652 <prefer><family>Courier New</family></prefer> 653 <default><family>monospace</family></default> 654</alias> 655 656<!-- 657 Provide required aliases for standard names 658 Do these after the users configuration file so that 659 any aliases there are used preferentially 660--> 661<alias> 662 <family>serif</family> 663 <prefer><family>Times New Roman</family></prefer> 664</alias> 665<alias> 666 <family>sans</family> 667 <prefer><family>Arial</family></prefer> 668</alias> 669<alias> 670 <family>monospace</family> 671 <prefer><family>Andale Mono</family></prefer> 672</alias> 673 674<-- 675 The example of the requirements of OR operator; 676 If the 'family' contains 'Courier New' OR 'Courier' 677 add 'monospace' as the alternative 678--> 679<match target="pattern"> 680 <test name="family" compare="eq"> 681 <string>Courier New</string> 682 </test> 683 <edit name="family" mode="prepend"> 684 <string>monospace</string> 685 </edit> 686</match> 687<match target="pattern"> 688 <test name="family" compare="eq"> 689 <string>Courier</string> 690 </test> 691 <edit name="family" mode="prepend"> 692 <string>monospace</string> 693 </edit> 694</match> 695 696</fontconfig> 697 </programlisting> 698 </refsect2> 699 <refsect2><title>User configuration file</title> 700 <para> 701This is an example of a per-user configuration file that lives in 702$XDG_CONFIG_HOME/fontconfig/fonts.conf 703 </para> 704 <programlisting> 705<?xml version="1.0"?> 706<!DOCTYPE fontconfig SYSTEM "urn:fontconfig:fonts.dtd"> 707<!-- $XDG_CONFIG_HOME/fontconfig/fonts.conf for per-user font configuration --> 708<fontconfig> 709 710<!-- 711 Private font directory 712--> 713<dir prefix="xdg">fonts</dir> 714 715<!-- 716 use rgb sub-pixel ordering to improve glyph appearance on 717 LCD screens. Changes affecting rendering, but not matching 718 should always use target="font". 719--> 720<match target="font"> 721 <edit name="rgba" mode="assign"><const>rgb</const></edit> 722</match> 723<!-- 724 use WenQuanYi Zen Hei font when serif is requested for Chinese 725--> 726<match> 727 <!-- 728 If you don't want to use WenQuanYi Zen Hei font for zh-tw etc, 729 you can use zh-cn instead of zh. 730 Please note, even if you set zh-cn, it still matches zh. 731 if you don't like it, you can use compare="eq" 732 instead of compare="contains". 733 --> 734 <test name="lang" compare="contains"> 735 <string>zh</string> 736 </test> 737 <test name="family"> 738 <string>serif</string> 739 </test> 740 <edit name="family" mode="prepend"> 741 <string>WenQuanYi Zen Hei</string> 742 </edit> 743</match> 744<!-- 745 use VL Gothic font when sans-serif is requested for Japanese 746--> 747<match> 748 <test name="lang" compare="contains"> 749 <string>ja</string> 750 </test> 751 <test name="family"> 752 <string>sans-serif</string> 753 </test> 754 <edit name="family" mode="prepend"> 755 <string>VL Gothic</string> 756 </edit> 757</match> 758</fontconfig> 759 </programlisting> 760 </refsect2> 761</refsect1> 762<refsect1><title>Files</title> 763 <para> 764<emphasis>fonts.conf</emphasis> 765contains configuration information for the fontconfig library 766consisting of directories to look at for font information as well as 767instructions on editing program specified font patterns before attempting to 768match the available fonts. It is in XML format. 769 </para> 770 <para> 771<emphasis>conf.d</emphasis> 772is the conventional name for a directory of additional configuration files 773managed by external applications or the local administrator. The 774filenames starting with decimal digits are sorted in lexicographic order 775and used as additional configuration files. All of these files are in XML 776format. The master fonts.conf file references this directory in an 777<include> directive. 778 </para> 779 <para> 780<emphasis>fonts.dtd</emphasis> 781is a DTD that describes the format of the configuration files. 782 </para> 783 <para> 784<emphasis>$XDG_CONFIG_HOME/fontconfig/conf.d</emphasis> and <emphasis>~/.fonts.conf.d</emphasis> 785is the conventional name for a per-user directory of (typically 786auto-generated) configuration files, although the 787actual location is specified in the global fonts.conf file. please note that ~/.fonts.conf.d is deprecated now. it will not be read by default in the future version. 788 </para> 789 <para> 790<emphasis>$XDG_CONFIG_HOME/fontconfig/fonts.conf</emphasis> and <emphasis>~/.fonts.conf</emphasis> 791is the conventional location for per-user font configuration, although the 792actual location is specified in the global fonts.conf file. please note that ~/.fonts.conf is deprecated now. it will not be read by default in the future version. 793 </para> 794 <para> 795<emphasis>$XDG_CACHE_HOME/fontconfig/*.cache-*</emphasis> and <emphasis> ~/.fontconfig/*.cache-*</emphasis> 796is the conventional repository of font information that isn't found in the 797per-directory caches. This file is automatically maintained by fontconfig. please note that ~/.fontconfig/*.cache-* is deprecated now. it will not be read by default in the future version. 798 </para> 799</refsect1> 800<refsect1><title>Environment variables</title> 801 <para> 802<emphasis>FONTCONFIG_FILE</emphasis> 803is used to override the default configuration file. 804 </para> 805 <para> 806<emphasis>FONTCONFIG_PATH</emphasis> 807is used to override the default configuration directory. 808 </para> 809 <para> 810<emphasis>FONTCONFIG_SYSROOT</emphasis> 811is used to set a default sysroot directory. 812 </para> 813 <para> 814<emphasis>FC_DEBUG</emphasis> 815is used to output the detailed debugging messages. see <link linkend="debug">Debugging Applications</link> section for more details. 816 </para> 817 <para> 818<emphasis>FC_DBG_MATCH_FILTER</emphasis> 819is used to filter out the patterns. this takes a comma-separated list of object names and effects only when FC_DEBUG has MATCH2. see <link linkend="debug">Debugging Applications</link> section for more details. 820 </para> 821 <para> 822<emphasis>FC_LANG</emphasis> 823is used to specify the default language as the weak binding in the query. if this isn't set, the default language will be determined from current locale. 824 </para> 825 <para> 826<emphasis>FONTCONFIG_USE_MMAP</emphasis> 827is used to control the use of mmap(2) for the cache files if available. this take a boolean value. fontconfig will checks if the cache files are stored on the filesystem that is safe to use mmap(2). explicitly setting this environment variable will causes skipping this check and enforce to use or not use mmap(2) anyway. 828 </para> 829 <para> 830<emphasis>SOURCE_DATE_EPOCH</emphasis> 831is used to ensure <literal>fc-cache(1)</literal> generates files in a deterministic manner in order to support reproducible builds. When set to a numeric representation of UNIX timestamp, fontconfig will prefer this value over using the modification timestamps of the input files in order to identify which cache files require regeneration. If <literal>SOURCE_DATE_EPOCH</literal> is not set (or is newer than the mtime of the directory), the existing behaviour is unchanged. 832 </para> 833</refsect1> 834<refsect1><title>See Also</title> 835 <para> 836fc-cat(1), fc-cache(1), fc-list(1), fc-match(1), fc-query(1), <ulink url="https://reproducible-builds.org/specs/source-date-epoch/">SOURCE_DATE_EPOCH</ulink>. 837 </para> 838</refsect1> 839<refsect1><title>Version</title> 840 <para> 841Fontconfig version &version; 842 </para> 843</refsect1> 844</refentry> 845