general-docs / texi / xemacs / fontconfig.texi

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\input texinfo.tex
@c %**start of header
@c This @setfilename tells makeinfo to DTRT for the *installed* .texi file.
@setfilename fontconfig.info
@settitle Fontconfig: Font configuration and customization library

@set synched-to-pkg-version 1.0
@set synched-to-doc-versions Package: @value{synched-to-package-version}
@set last-released-month-year October 2003
@set last-released-date 20 October 2003

@footnotestyle separate
@paragraphindent 2
@c %**end of header

@dircategory Permissively licensed documentation
@direntry
* fontconfig::                Managing font metainformation.
@end direntry

@setchapternewpage odd

@shorttitlepage Fontconfig

@titlepage
@title Fontconfig
@subtitle Font configuration and customization library
@subtitle A Rendering-Engine-Independent Library
@subtitle for Managing Font Metainformation

@author Keith Packard
@author Stephen J. Turnbull

@end titlepage

@ifinfo
@node Top, Copying, (dir), (dir)
@top Fontconfig

This file documents fontconfig, a rendering-engine-independent library
for managing font metainformation (@emph{i.e.}, everything but the glyph
data themselves).  It is @emph{not} part of XEmacs.

Copyright  2002 Keith Packard, member of The XFree86 Project, Inc.
Copyright  2003 Stephen J. Turnbull, member of the XEmacs Project

In the following notice, the term "Authors" refers to the copyright
holders listed above, and "Documentation" refers to this version of the
documentation supplied by Keith Packard, as adapted to Texinfo by
Stephen J. Turnbull.  The fontconfig library itself and the original
documentation are covered by a similar license.

Permission to use, copy, modify, distribute, and sell this Documentation
for any purpose is hereby granted without fee, provided that the above
copyright notice appear in all copies and that both that copyright
notice and this permission notice appear in copies of the Documentation,
and that the names of the Authors not be used in advertising or
publicity pertaining to distribution of the Documentation without
specific, written prior permission.  The Authors make no representations
about the suitability of this Documentation for any purpose.  It is
provided "as is" without express or implied warranty.

THE AUTHORS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS DOCUMENTATION,
INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
EVENT SHALL THE AUTHORS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
PERFORMANCE OF THIS DOCUMENTATION.

@c I believe that this document can legally be distributed under the
@c above permission.  rms's opinion is that there is nothing left of
@c `texinfo.tex' after processing this document, and therefore nothing
@c forces this document to be distributed under GPL.

@c The original permissively licensed document may be obtained in
@c distributions of the fontconfig library available from the CVS
@c repository of the XFree86 Project in module xc/extra/fontconfig.

@end ifinfo

@menu
* Copying::
* Overview::
* The fontconfig API::
* Configuration File Format::
* Files::
* Authors::

@detailmenu
 --- The Detailed Node Listing ---

Overview

* Font Configuration::
* Font Properties::
* Font Matching::
* Font List Matching::
* Font Names::
* LANG Tags::

The fontconfig API

* Data Types::
* Functions::

Functions

* FcMatrix::
* FcCharSet::
* FcValue::
* FcPattern::
* FcFontSet::
* FcObjectSet::
* FcObjectType::
* Querying Fonts and Their Properties::
* Initialization::
* FcAtomic::
* FreeType-Specific Functions::
* XML-Specific Functions::
* File and Directory Routines::
* FcStrSet and FcStrList::
* String Utilities::

Configuration File Format

* Example System Configuration File::
* Example User Configuration File::

@end detailmenu
@end menu

@node Copying, Overview, Top, Top
@chapter Copying

The fontconfig library and the accompanying documentation are covered by
the following copyright notice and license, except for this Texinfo
version which has additional authors but is otherwise substantially the
same.

Copyright  2002 Keith Packard, member of The XFree86 Project, Inc.

Permission to use, copy, modify, distribute, and sell this software and its
documentation for any purpose is hereby granted without fee, provided that
the above copyright notice appear in all copies and that both that
copyright notice and this permission notice appear in supporting
documentation, and that the name of Keith Packard not be used in
advertising or publicity pertaining to distribution of the software without
specific, written prior permission.  Keith Packard makes no
representations about the suitability of this software for any purpose.  It
is provided "as is" without express or implied warranty.

KEITH PACKARD DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
EVENT SHALL KEITH PACKARD BE LIABLE FOR ANY SPECIAL, INDIRECT OR
CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
PERFORMANCE OF THIS SOFTWARE.

@node Overview, The fontconfig API, Copying, Top
@chapter Overview

@c DESCRIPTION
Fontconfig is a library designed to provide system-wide font
configuration, customization and application access.

This manual describes fontconfig version 1.0.2.

@c 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.

@menu
* Font Configuration::          
* Font Properties::             
* Font Matching::               
* Font List Matching::          
* Font Names::                  
* LANG Tags::                   
@end menu

@node Font Configuration, Font Properties, Overview, Overview
@section Font Configuration

The configuration module consists of the FcConfig datatype, libexpat and
FcConfigParse which walks over an XML tree and amends a configuration with
data found within.  From an external perspective, configuration of the
library consists of generating a valid XML tree and feeding that to
FcConfigParse.  The only other mechanism provided to applications for
changing the running configuration is to add fonts and directories to the
list of application-provided font files.  

The intent is to make font configuration 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 applications 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 configuration of fonts for all applications
can be centralized in one place.  Centralizing font configuration will
simplify and regularize font installation and customization.

@node Font Properties, Font Matching, Font Configuration, Overview
@section 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.  Some symbolic
constants are provided for common values or enumerated types.
@xref{Constants}, for the list of standard properties and values.


@node Font Matching, Font List Matching, Font Properties, Overview
@section 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 an FcPattern
object.  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 consists 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 values 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, pixelsize, 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 properties
found in the pattern but not found in the font itself; this permits 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 pattern.  This modified
pattern is returned to the application.

The return value contains sufficient information to locate and rasterize 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.

@node Font List Matching, Font Names, Font Matching, Overview
@section Font List Matching

While many applications want to locate a single font best matching their
search criteria, other applications need to build a set of fonts which can
be used to present any Unicode data.  Fontconfig provides an API to generate
a list sorted by the nearness of each font to the pattern.  Every font in
the system is considered, the best matching fonts are placed first.  The
application then can select whether the remaining fonts are unconditionally 
included in the list, or whether they are included only if they cover
portions of Unicode not covered by any of the preceeding fonts.

The list resulting from this match is represented by references to the
original font patterns and so consumes very little memory.  Using a list
entry involves creating a pattern which combines the information from the
font with the information from the original pattern and executing the font
substitutions.

@node Font Names, LANG Tags, Font List Matching, Overview
@section 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:

@example
	<families>-<point sizes>:<name1>=<values1>:<name2>=<values2>...
@end example

Values in a list are separated with commas.  A hyphen or comma in a family
name must be escaped with a backslash.  The name needn't include either
families or point sizes; they can be elided.  If the family name only is
given, the hyphen may be omitted.  If there are no additional properties,
no trailing colon should be used.  In addition, there are
symbolic constants that simultaneously indicate both a name and a value.
Here are some examples:

@example
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
Mikachan\-PB-16             12 point Mikachan-PB
@end example

@node LANG Tags,  , Font Names, Overview
@section 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.

@node The fontconfig API, Configuration File Format, Overview, Top
@chapter The fontconfig API

@example
#include <fontconfig/fontconfig.h>
#include <fontconfig/fcfreetype.h>
@end example

@menu
* Constants::
* Data Types::                   
* Functions::                   
@end menu

@node Constants, Data Types, The fontconfig API, The fontconfig API

While fontconfig is designed to be extensible, it provides a comprehensive
set of standard properties and values for fonts.

The following table gives the list of standard font properties.  The property
name is represented as a string.  In C code a C preprocessor symbol may be
used to help with typo detection.

@example
Property        CPP symbol      Type    Description

family          FC_FAMILY       String  Font family name
style           FC_STYLE        String  Font style. Overrides weight and slant
slant           FC_SLANT        Int     Italic, oblique or roman
weight          FC_WEIGHT       Int     Light, medium, demibold, bold or black
size            FC_SIZE         Double  Point size
aspect          FC_ASPECT       Double  Stretch glyphs horizontally, then hint
pixelsize       FC_PIXEL_SIZE   Double  Pixel size
spacing         FC_SPACING      Int     Proportional, monospace or charcell
foundry         FC_FOUNDRY      String  Font foundry name
antialias       FC_ANTIALIAS    Bool    Should glyphs be antialiased?
hinting         FC_HINTING      Bool    Should the rasterizer use hinting?
verticallayout  FC_VERTICAL_LAYOUT Bool Use vertical layout
autohint        FC_AUTOHINT     Bool    Use autohinter instead of normal hinter
globaladvance   FC_GLOBAL_ADVANCE Bool  Use font global advance data
file            FC_FILE         String  The filename holding the font
index           FC_INDEX        Int     The index of the font within the file
ftface          FC_FT_FACE      FT_Face Use the specified FreeType face object
rasterizer      FC_RASTERIZER   String  Which rasterizer is in use
outline         FC_OUTLINE      Bool    Whether the glyphs are outlines
scalable        FC_SCALABLE     Bool    Whether glyphs can be scaled
scale           FC_SCALE        Double  Point->pixel conversion scale factor
dpi             FC_DPI          Double  Target dots per inch
rgba            FC_RGBA         Int     unknown, rgb, bgr, vrgb, vbgr, none
                                        - subpixel geometry
source		FC_SOURCE	String  X11, freetype
minspace        FC_MINSPACE     Bool    Eliminate leading from line spacing
charset         FC_CHARSET      CharSet Unicode chars encoded by the font
lang            FC_LANG         String  List of RFC-3066-style languages
                                        this font supports
fontversion	FC_FONTVERSION  Int     From 'head' table
@end example

C code can check the fontconfig version number with the numerical
preprocessor constants @code{FC_MAJOR}, @code{FC_MINOR}, and
@code{FC_REVISION}, or use the combined constant @code{FC_VERSION}, defined
as @code{FC_MAJOR*10000 + FC_MINOR*100 + FC_REVISION}.

@c fontconfig.h details what FC_CACHE_VERSION is, exactly. 
The cache version is given by @code{FC_CACHE_VERSION}, and is a string, not
an integer.  This is normally appended to the end of the cache file name, so
multiple versions of fontconfig can peacefully co-exist.  The cache file
names are defined as @code{FC_DIR_CACHE_FILE} and @code{FC_USER_CACHE_FILE}.

The Boolean constants are @code{FcFalse} (0) and @code{FcTrue} (1).

Properties used to control the rasterizer, their preprocessor constants, and
their types, include:

@example
charwidth	FC_CHAR_WIDTH	Int
charheight	FC_CHAR_HEIGHT	Int
matrix          FC_MATRIX       FcMatrix
@end example

Preprocessor constants are defined for common standard font weights.  All are
Ints.

@example
FC_WEIGHT_LIGHT	    0
FC_WEIGHT_MEDIUM    100
FC_WEIGHT_DEMIBOLD  180
FC_WEIGHT_BOLD	    200
FC_WEIGHT_BLACK	    210
@end example

Preprocessor constants are defined for common standard slants.  All are Ints.

@example
FC_SLANT_ROMAN	    0
FC_SLANT_ITALIC	    100
FC_SLANT_OBLIQUE    110
@end example

Preprocessor constants are defined for the three spacing types.  All are
Ints, but should be treated as symbolic constants.

@example
FC_PROPORTIONAL	    0
FC_MONO		    100
FC_CHARCELL	    110
@end example

Preprocessor constants are defined for the subpixel orders.  All are
Ints, but should be treated as symbolic constants.

@example
FC_RGBA_UNKNOWN	    0
FC_RGBA_RGB	    1
FC_RGBA_BGR	    2
FC_RGBA_VRGB	    3
FC_RGBA_VBGR	    4
FC_RGBA_NONE	    5
@end example


@node Data Types, Functions, Constants, The fontconfig API
@section Data Types

@table @samp
@item FcChar8
@itemx FcChar16
@itemx FcChar32
@itemx FcBool
These are primitive data types; the FcChar* types hold precisely the number
of bits stated (if supported by the C implementation).  FcBool holds
one of two CPP symbols: FcFalse or FcTrue.

@item FcMatrix
An FcMatrix holds an affine transformation, usually used to reshape glyphs.
A small set of matrix operations are provided to manipulate these.

@example
	typedef struct _FcMatrix @{
		double xx, xy, yx, yy;
	@} FcMatrix;
@end example

@item FcCharSet
An FcCharSet is an abstract type that holds the set of encoded unicode chars
in a font.  Operations to build and compare these sets are provided.

@item FcType
Tags the kind of data stored in an FcValue.

@item FcValue
An FcValue object holds a single value with one of a number of different
types.  The 'type' tag indicates which member is valid.

@example
	typedef struct _FcValue @{
		FcType type;
		union @{
			const FcChar8 *s;
			int i;
			FcBool b;
			double d;
			const FcMatrix *m;
			const FcCharSet *c;
                	void *f;
                	const FcPattern *p;
	                const FcLangSet *l;
		@} u;
	@} FcValue;
@end example

@example
	type		Union member	Datatype

	FcTypeVoid	(none)		(none)
	FcTypeInteger	i		int
	FcTypeDouble	d		double
	FcTypeString	s		TcChar8 *
	FcTypeBool	b		b
	FcTypeMatrix	m		FcMatrix *
	FcTypeCharSet	c		FcCharSet *
        FcTypeFTFace    f               void *
                        p               FcPattern *
        FcTypeLangSet   l               FcLangSet *
@end example

@item FcPattern
holds a set of names with associated value lists; each name refers to a
property of a font.  FcPatterns are used as inputs to the matching code as
well as holding information about specific fonts.  Each property can hold
one or more values; conventionally all of the same type, although the
interface doesn't demand that.

@item FcFontSet

@example
	typedef struct _FcFontSet @{
		int nfont;
		int sfont;
		FcPattern **fonts;
	@} FcFontSet;
@end example

An FcFontSet contains a list of FcPatterns.  Internally fontconfig uses this
data structure to hold sets of fonts.  Externally, fontconfig returns the
results of listing fonts in this format.  'nfont' holds the number of
patterns in the 'fonts' array; 'sfont' is used to indicate the size of that
array.

@item FcStrSet
@itemx FcStrList
FcStrSet holds a list of strings that can be appended to and enumerated.
Its unique characteristic is that the enumeration works even while strings
are appended during enumeration.  FcStrList is used during enumeration to
safely and correctly walk the list of strings even while that list is edited
in the middle of enumeration.

@item FcObjectSet

@example
	typedef struct _FcObjectSet @{
		int nobject;
		int sobject;
		const char **objects;
	@} FcObjectSet;
@end example
holds a set of names and is used to specify which fields from fonts are
placed in the the list of returned patterns when listing fonts.

@item FcObjectType

@example
	typedef struct _FcObjectType @{
		const char *object;
		FcType type;
	@} FcObjectType;
@end example
marks the type of a pattern element generated when parsing font names.
Applications can add new object types so that font names may contain the new
elements.

@item FcConstant

@example
	typedef struct _FcConstant @{
	    const FcChar8 *name;
	    const char *object;
	    int value;
	@} FcConstant;
@end example
Provides for symbolic constants for new pattern elements.  When 'name' is
seen in a font name, an 'object' element is created with value 'value'.

@item FcBlanks
holds a list of Unicode chars which are expected to be blank; unexpectedly
blank chars are assumed to be invalid and are elided from the charset
associated with the font.

@item FcFileCache
holds the per-user cache information for use while loading the font
database. This is built automatically for the current configuration when
that is loaded.  Applications must always pass '0' when one is requested.

@item FcConfig
holds a complete configuration of the library; there is one default
configuration, other can be constructed from XML data structures.  All
public entry points that need global data can take an optional FcConfig*
argument; passing 0 uses the default configuration.  FcConfig objects hold two
sets of fonts, the first contains those specified by the configuration, the
second set holds those added by the application at run-time.  Interfaces
that need to reference a particulat set use one of the FcSetName enumerated
values.

@item FcSetName
Specifies one of the two sets of fonts available in a configuration;
FcSetSystem for those fonts specified in the configuration and
FcSetApplication which holds fonts provided by the application.

@item FcResult
Used as a return type for functions manipulating FcPattern objects.

@example
Result code		Meaning
FcResultMatch		Object exists with the specified ID
FcResultNoMatch		Object doesn't exist at all
FcResultTypeMismatch	Object exists, but the type doesn't match
FcResultNoId		Object exists, but has fewer values than specified
@end example

@item FcAtomic
Used for locking access to config files.  Provides a safe way to update
configuration files.

@item FcMatchKind
An enumeration containing @code{FcMatchPattern} and @code{FcMatchFont}.

@item FcLangResult
An enumeration containing @code{FcLangEqual}, @code{FcLangDifferentCountry},
and @code{FcLangDifferentLang}.  Presumably @code{FcLangDifferentLang}
implies @code{FcLangDifferentCountry}.

@item FcSetName
An enumeration containing @code{FcSetSystem} and @code{FcSetApplication}.

@item FcEndian
An enumeration containing @code{FcEndianBig} and @code{FcEndianLittle}.
@end table

@node Functions,  , Data Types, The fontconfig API
@section Functions

@menu
* FcMatrix::
* FcCharSet::
* FcValue::
* FcPattern::
* FcFontSet::
* FcObjectSet::
* FcObjectType::
* FcLangSet::
* Querying Fonts and Their Properties::
* Initialization::
* FcAtomic::
* FreeType-Specific Functions::
* XML-Specific Functions::
* File and Directory Routines::
* FcStrSet and FcStrList::
* String Utilities::
@end menu

@node FcMatrix, FcCharSet, Functions, Functions
@subsection FcMatrix

FcMatrix structures hold an affine transformation in matrix form.

@example
#define FcMatrixInit(m)	((m)->xx = (m)->yy = 1, (m)->xy = (m)->yx = 0)
@end example
Initializes a matrix to the identify transformation.

@deftypefun {FcMatrix *} FcMatrixCopy (const FcMatrix *@var{mat})

Allocates a new FcMatrix and copies 'mat' into it.
@end deftypefun

@deftypefun FcBool FcMatrixEqual (const FcMatrix *@var{mat1}, const FcMatrix *var{mat2})

Returns FcTrue if 'mat1' and 'mat2' are equal, else FcFalse.
@end deftypefun

@deftypefun void FcMatrixMultiply (FcMatrix *@var{result}, const FcMatrix *@var{a}, const FcMatrix *var{b})

Multiplies 'a' and 'b' together, placing the result in 'result'.  'result'
may refer to the same matrix as either 'a' or 'b'.
@end deftypefun

@deftypefun void FcMatrixRotate (FcMatrix *m, double c, double s)

If 'c' is cos(angle) and 's' is sin(angle), FcMatrixRotate rotates the
matrix by 'angle'.
@end deftypefun

@deftypefun void FcMatrixScale (FcMatrix *m, double sx, double sy)

Scales 'm' by 'sx' in the horizontal dimension and 'sy' in the
vertical dimension.
@end deftypefun

@deftypefun void FcMatrixShear (FcMatrix *m, double sh, double sv)
Shears 'm' by 'sh' in the horizontal direction and 'sv' in the
vertical direction.
@end deftypefun

@node FcCharSet, FcValue, FcMatrix, Functions
@subsection FcCharSet

An FcCharSet is a boolean array indicating a set of unicode chars.  Those
associated with a font are marked constant and cannot be edited.
FcCharSets may be reference counted internally to reduce memory consumption;
this may be visible to applications as the result of FcCharSetCopy may
return its argument, and that CharSet may remain unmodifiable.

When represented as a string, an FcCharSet is not a pure bitmap; octet
values are limited such that FcCharSet objects, when printed, are valid
ASCII characters.

@deftypefun {FcCharSet *} FcCharSetCreate (void)

Creates an empty FcCharSet object.
@end deftypefun

@deftypefun void FcCharSetDestroy (FcCharSet *fcs)

Frees an FcCharSet object.
@end deftypefun

@deftypefun FcBool FcCharSetAddChar (FcCharSet *fcs, FcChar32 ucs4)

Adds a single unicode char to the set, returning FcFalse on
failure, either as a result of a constant set or from running out of memory.
@end deftypefun

@deftypefun {FcCharSet *} FcCharSetCopy (FcCharSet *src)

Makes a copy of 'src'; note that this may not actually do anything more than
increment the reference count on 'src'.
@end deftypefun

@deftypefun FcBool FcCharSetEqual (const FcCharSet *a, const FcCharSet *b)

Returns whether 'a' and 'b' contain the same set of unicode chars.
@end deftypefun

@deftypefun {FcCharSet *} FcCharSetIntersect (const FcCharSet *a, const FcCharSet *b)

Returns a set including only those chars found in both 'a' and 'b'.
@end deftypefun

@deftypefun {FcCharSet *} FcCharSetUnion (const FcCharSet *a, const FcCharSet *b);

Returns a set including only those chars found in either 'a' or 'b'.
@end deftypefun

@deftypefun {FcCharSet *} FcCharSetSubtract (const FcCharSet *a, const FcCharSet *b)

Returns a set including only those chars found in 'a' but not 'b'.
@end deftypefun

@deftypefun FcBool FcCharSetHasChar (const FcCharSet *fcs, FcChar32 ucs4)

Returns whether 'fcs' contains the char 'ucs4'.
@end deftypefun

@deftypefun FcChar32 FcCharSetCount (const FcCharSet *a)

Returns the total number of unicode chars in 'a'.
@end deftypefun

@deftypefun FcChar32 FcCharSetIntersectCount (const FcCharSet *a, const FcCharSet *b)

Returns the number of chars that are in both 'a' and 'b'.
@end deftypefun

@deftypefun FcChar32 FcCharSetSubtractCount (const FcCharSet *a, const FcCharSet *b)

Returns the number of chars that are in 'a' but not in 'b'.
@end deftypefun

@deftypefun FcBool FcCharSetIsSubset (const FcCharSet *a, const FcCharSet *b)

Returns whether 'a' is a subset of 'b'.
@end deftypefun

@deftypefun FcChar32 FcCharSetFirstPage (const FcCharSet *a, FcChar32 [FC_CHARSET_MAP_SIZE], FcChar32 *next)

Builds an array of bits marking the first page of Unicode coverage of 'a'.
Returns the base of the array.  'next' contains the next page in the font.
@end deftypefun

@deftypefun FcChar32 FcCharSetNextPage (const FcCharSet *a, FcChar32 [FC_CHARSET_MAP_SIZE], FcChar32 *next)

Builds an array of bits marking the Unicode coverage of 'a' for page '*next'.
Returns the base of the array.  'next' contains the next page in the font.
@end deftypefun

@node FcValue, FcPattern, FcCharSet, Functions
@subsection FcValue

FcValue is a structure containing a type tag and a union of all possible
data types.  The tag is an enum of type FcType and is intended to provide
a measure of run-time typechecking, although that depends on careful
programming.

@deftypefun void FcValueDestroy (FcValue v)

Frees any memory referenced by `v'.  Values of type FcTypeString,
FcTypeMatrix and FcTypeCharSet reference memory, the other types do not.
@end deftypefun

@deftypefun FcValue FcValueSave (FcValue v)

Returns a copy of `v' duplicating any object referenced by it so that `v'
may be safely destroyed without harming the new value.
@end deftypefun

@deftypefun void FcValuePrint (const FcValue v)

Prints an easily readable version of the value to stdout.  There is
no provision for reparsing data in this format, it's just for diagnostics
and debugging.
@end deftypefun


@node FcPattern, FcFontSet, FcValue, Functions
@subsection FcPattern

An FcPattern is an opaque type that holds both patterns to match against the
available fonts, as well as the information about each font.

@deftypefun {FcPattern *} FcPatternCreate (void)

Creates a pattern with no properties; used to build patterns from scratch.
@end deftypefun

@deftypefun void FcPatternDestroy (FcPattern *p)

Destroys a pattern, in the process destroying all related values.
@end deftypefun

@deftypefun FcBool FcPatternEqual (const FcPattern *pa, const FcPattern *pb);

Returns whether 'pa' and 'pb' are exactly alike.
@end deftypefun

@deftypefun FcBool FcPatternEqualSubset (const FcPattern *pa, const FcPattern *pb, const FcObjectSet *os)

Returns whether 'pa' and 'pb' have exactly the same values for all of the
objects in 'os'.
@end deftypefun

@deftypefun FcChar32 FcPatternHash (const FcPattern *p)

Returns a 32-bit number which is the same for any two patterns which are
exactly alike.
@end deftypefun

@deftypefun FcBool FcPatternAdd (FcPattern *p, const char *object, FcValue value, FcBool append)

Adds a single value to the list of values associated with the property named
`object'.  If `append' is FcTrue, the value is added at the end of any
existing list, otherwise it is inserted at the begining.  `value' is saved
(with FcValueSave) when inserted into the pattern so that the library
retains no reference to any application-supplied data structure.
@end deftypefun

@deftypefun FcBool FcPatternAddWeak (FcPattern *p, const char *object, FcValue value, FcBool append)

FcPatternAddWeak is essentially the same as FcPatternAdd except that any
values added to the list have binding 'weak' instead of 'strong'.
@end deftypefun

@deftypefun FcBool FcPatternAddInteger (FcPattern *p, const char *object, int i)
@deftypefunx FcBool FcPatternAddDouble (FcPattern *p, const char *object, double d)
@deftypefunx FcBool FcPatternAddString (FcPattern *p, const char *object, const char *s)
@deftypefunx FcBool FcPatternAddMatrix (FcPattern *p, const char *object, const FcMatrix *s)
@deftypefunx FcBool FcPatternAddCharSet (FcPattern *p, const char *object, const FcCharSet *c)
@deftypefunx FcBool FcPatternAddBool (FcPattern *p, const char *object, FcBool b)

These are all convenience functions that insert objects of the specified
type into the pattern.  Use these in preference to FcPatternAdd as they
will provide compile-time typechecking.  These all append values to
any existing list of values.
@end deftypefun

@deftypefun FcResult FcPatternGet (FcPattern *p, const char *object, int id, FcValue *v)

Returns in `v' the `id'th value associated with the property `object'.
The value returned is not a copy, but rather refers to the data stored
within the pattern directly.  Applications must not free this value.
@end deftypefun

@deftypefun FcResult FcPatternGetInteger (FcPattern *p, const char *object, int id, int *i);
@deftypefunx FcResult FcPatternGetDouble (FcPattern *p, const char *object, int id, double *d);
@deftypefunx FcResult FcPatternGetString (FcPattern *p, const char *object, int id, char **const s);
@deftypefunx FcResult FcPatternGetMatrix (FcPattern *p, const char *object, int id, FcMatrix **s);
@deftypefunx FcResult FcPatternGetCharSet (FcPattern *p, const char *object, int id, FcCharSet **c);
@deftypefunx FcResult FcPatternGetBool (FcPattern *p, const char *object, int id, FcBool *b);

These are convenience functions that call FcPatternGet and verify that the
returned data is of the expected type. They return FcResultTypeMismatch if
this is not the case.  Note that these (like FcPatternGet) do not make a
copy of any data structure referenced by the return value.  Use these
in preference to FcPatternGet to provide compile-time typechecking.
@end deftypefun

@deftypefun {FcPattern *} FcPatternBuild (FcPattern *orig, ...);
@deftypefunx FcPattern *FcPatternVaBuild (FcPattern *orig, va_list va)

Builds a pattern using a list of objects, types and values.  Each
value to be entered in the pattern is specified with three arguments:
@enumerate
@item
Object name, a string describing the property to be added.
@item
Object type, one of the FcType enumerated values
@item
Value, not an FcValue, but the raw type as passed to any of the
FcPatternAdd<type> functions.  Must match the type of the second
argument.
@end enumerate

The argument list is terminated by a null object name, no object type nor
value need be passed for this.  The values are added to `pattern', if
`pattern' is null, a new pattern is created.  In either case, the pattern is
returned. Example:

@example
pattern = FcPatternBuild (0, FC_FAMILY, FtTypeString, "Times", (char *) 0);
@end example

FcPatternVaBuild is used when the arguments are already in the form of a
varargs value.
@end deftypefun

@deftypefun FcBool FcPatternDel (FcPattern *p, const char *object)

Deletes all values associated with the property `object', returning 
whether the property existed or not.
@end deftypefun

@deftypefun void FcPatternPrint (const FcPattern *p)

Prints an easily readable version of the pattern to stdout.  There is
no provision for reparsing data in this format, it's just for diagnostics
and debugging.
@end deftypefun

@deftypefun void FcDefaultSubstitute (FcPattern *pattern)

Supplies default values for underspecified font patterns:
@itemize
@item
Patterns without a specified style or weight are set to Medium
@item
Patterns without a specified style or slant are set to Roman
@item
Patterns without a specified pixel size are given one computed from
any specified point size (default 12), dpi (default 75) and scale (default
1).
@end itemize
@end deftypefun

@deftypefun {FcPattern *} FcNameParse (const char *name)

Converts 'name' from the standard text format described above into a pattern.
@end deftypefun

@deftypefun FcChar8 *FcNameUnparse (FcPattern *pat)

Converts the given pattern into the standard text format described above.
The return value is not static, but instead refers to newly allocated memory
which should be freed by the caller.
@end deftypefun

@node FcFontSet, FcObjectSet, FcPattern, Functions
@subsection FcFontSet

An FcFontSet simply holds a list of patterns; these are used to return the
results of listing available fonts.

@deftypefun FcFontSet *FcFontSetCreate (void)

Creates an empty font set.
@end deftypefun

@deftypefun void FcFontSetDestroy (FcFontSet *s);

Destroys a font set.  Note that this destroys any referenced patterns as
well.
@end deftypefun

@deftypefun FcBool FcFontSetAdd (FcFontSet *s, FcPattern *font)

Adds a pattern to a font set.  Note that the pattern is not copied before
being inserted into the set.
@end deftypefun

@deftypefun void FcFontSetPrint (const FcFontSet *s)

Prints an easily readable version of the font set to stdout.  There is
no provision for reparsing data in this format, it's just for diagnostics
and debugging.
@end deftypefun


@node FcObjectSet, FcObjectType, FcFontSet, Functions
@subsection FcObjectSet

An FcObjectSet holds a list of pattern property names; it is used to
indicate which properties are to be returned in the patterns from
FcFontList.

@deftypefun FcObjectSet *FcObjectSetCreate (void)

Creates an empty set.
@end deftypefun

@deftypefun FcBool FcObjectSetAdd (FcObjectSet *os, const char *object)

Adds a property name to the set.
@end deftypefun

@deftypefun void FcObjectSetDestroy (FcObjectSet *os)

Destroys an object set.
@end deftypefun

@deftypefun FcObjectSet *FcObjectSetBuild (const char *first, ...)
@deftypefunx FcObjectSet *FcObjectSetVaBuild (const char *first, va_list va)

These build an object set from a null-terminated list of property names.
@end deftypefun

@node FcObjectType, FcLangSet, FcObjectSet, Functions
@subsection FcObjectType

Provides for application-specified font name object types so that new
pattern elements can be generated from font names.

@deftypefun FcBool FcNameRegisterObjectTypes (const FcObjectType *types, int ntype)

Register 'ntype' new object types.
@end deftypefun

@deftypefun FcBool FcNameUnregisterObjectTypes (const FcObjectType *types, int ntype)

Unregister 'ntype' object types.
@end deftypefun

@deftypefun const FcObjectType *FcNameGetObjectType (const char *object)

Return the object type for the pattern element named 'object'.
@end deftypefun

FcConstant

Provides for application-specified symbolic constants for font names.

@deftypefun FcBool FcNameRegisterConstants (const FcConstant *consts, int nconsts)

Register 'nconsts' new symbolic constants.
@end deftypefun

@deftypefun FcBool FcNameUnregisterConstants (const FcConstant *consts, int nconsts)

Unregister 'nconsts' symbolic constants.
@end deftypefun

@deftypefun const FcConstant *FcNameGetConstant (FcChar8 *string)

Return the FcConstant structure related to symbolic constant 'string'.
@end deftypefun

@deftypefun FcBool FcNameConstant (FcChar8 *string, int *result)

Returns whether a symbolic constant with name 'string' is registered,
placing the value of the constant in 'result' if present.
@end deftypefun


@node FcLangSet, Querying Fonts and Their Properties, FcObjectType, Functions
@subsection FcLangSet

An @code{FcLangSet} holds a set of RFC 3066 language tags, @ref{LANG Tags}.
This module provides functions to determine whether a given language is
fully supported by a font.  Partial support can be determined using the
font's character set, @ref{FcCharSet}.

@deftypefun FcLangSet *FcLangSetCreate (void);

Create an empty @code{FcLangSet}.
@end deftypefun

@deftypefun void FcLangSetDestroy (FcLangSet *ls);

Destroy a @code{FcLangSet}, freeing any associated storage.
@end deftypefun

@deftypefun FcLangSet *FcLangSetCopy (const FcLangSet *ls);

Copy @var{ls} to a newly allocated @code{FcLangSet}.
@end deftypefun

@deftypefun FcBool FcLangSetAdd (FcLangSet *ls, const FcChar8 *lang);

Add @var{lang} to @code{FcLangSet} @var{ls}.
@end deftypefun

@deftypefun FcLangResult FcLangSetHasLang (const FcLangSet *ls, const FcChar8 *lang);

Check whether @var{lang} is a member of @code{FcLangSet} @var{ls}.  Note that
the return value is a @code{FcLangResult}, not a Boolean.
@end deftypefun

@deftypefun FcLangResult FcLangSetCompare (const FcLangSet *lsa, const FcLangSet *lsb);
@c The actual code isn't remotely clear either. And I suspect it's buggy; 
@c cf this in FcLangSetEqual: 
@c
@c  for (i = 0; i < NUM_LANG_SET_MAP; i++)
@c  {
@c     if (lsa->map[i] != lsb->map[i])
@c          return FcFalse;
@c  }
@c
@c vs. this in FcLangSetCompare: 
@c
@c  for (i = 0; i < NUM_LANG_SET_MAP; i++)
@c      if (lsa->map[i] & lsb->map[i])
@c          return FcLangEqual;

#### Document me.
@end deftypefun

@deftypefun FcBool FcLangSetEqual (const FcLangSet *lsa, const FcLangSet *lsb);

Check whether the @code{FcLangSet}s @var{lsa} and @var{lsb} contain the same
members.
@end deftypefun

@deftypefun FcChar32 FcLangSetHash (const FcLangSet *ls);

Return a hash value; two @code{FcLangSet}s which hash to different values
cannot contain the same members.
@end deftypefun


@node Querying Fonts and Their Properties, Initialization, FcLangSet, Functions
@subsection Querying Fonts and Their Properties

An FcBlanks object holds a list of Unicode chars which are expected to
be blank when drawn.  When scanning new fonts, any glyphs which are
empty and not in this list will be assumed to be broken and not placed in
the FcCharSet associated with the font.  This provides a significantly more
accurate CharSet for applications.

@deftypefun FcBlanks *FcBlanksCreate (void)

Creates an empty FcBlanks object.
@end deftypefun

@deftypefun void FcBlanksDestroy (FcBlanks *b)

Destroys an FcBlanks object, freeing any associated memory.
@end deftypefun

@deftypefun FcBool FcBlanksAdd (FcBlanks *b, FcChar32 ucs4)

Adds a single character to an FcBlanks object, returning FcFalse
if this process ran out of memory.
@end deftypefun

@deftypefun FcBool FcBlanksIsMember (FcBlanks *b, FcChar32 ucs4)

Returns whether the specified FcBlanks object contains the indicated Unicode
value.
@end deftypefun

The site or user may specify substitutions for certain font patterns,
for convenience or to get more accurate results for the local
installation or preferences.  These functions execute the substitution
based on a specified configuration.

@deftypefun FcBool FcConfigSubstituteWithPat (FcConfig *config, FcPattern *p, FcPattern *p_pat FcMatchKind kind)

Performs the sequence of pattern modification operations, if 'kind' is
FcMatchPattern, then those tagged as pattern operations are applied, else 
if 'kind' is FcMatchFont, those tagged as font operations are applied and
p_pat is used for <test> elements with target=pattern.
@end deftypefun

@deftypefun FcBool FcConfigSubstitute (FcConfig *config, FcPattern *p, FcMatchKind kind)

Calls FcConfigSubstituteWithPat setting p_pat to NULL.
@end deftypefun

The following functions return fonts that match a certain pattern.
@code{FcFontRenderPrepare} and @code{FcFontMatch} always return a single
best match.  @code{FcFontList} returns the list of fonts that match a a
given pattern on a certain set of properties.  @code{FcFontSort} returns
the entire list of fonts, sorted in order of match quality, possibly
filtering out fonts that do not provide additional characters beyond
those provided by preferred fonts.

@deftypefun {FcPattern *} FcFontRenderPrepare (FcConfig *config, FcPattern *pat, FcPattern *font)

Creates a new pattern consisting of elements of 'font' not appearing
in 'pat', elements of 'pat' not appearing in 'font' and the best matching
value from 'pat' for elements appearing in both.  The result is passed to
FcConfigSubstitute with 'kind' FcMatchFont and then returned.
@end deftypefun

@deftypefun {FcPattern *} FcFontMatch (FcConfig *config, FcPattern *p, FcResult *result)

Returns the font in 'config' most close matching 'p'.  This function
should be called only after FcConfigSubstitute and FcDefaultSubstitute have
been called for 'p'; otherwise the results will not be correct.
@end deftypefun

@deftypefun FcFontSet *FcFontList (FcConfig *config, FcPattern *p, FcObjectSet *os)

Selects fonts matching 'p', creates patterns containing only the objects in
'os' from those fonts, and returns the set of unique such patterns.

The FcFontSet returned by FcFontList is destroyed by calling FcFontSetDestroy.
@end deftypefun

@deftypefun FcFontSet *FcFontSort (FcConfig *config, FcPattern *p, FcBool trim, FcCharSet **csp, FcResult *result)

Returns the list of all fonts sorted by closeness to 'p'.  If 'trim' is
FcTrue, elements in the list which don't include Unicode coverage not
provided by earlier elements in the list are elided.  The union of
Unicode coverage of all of the fonts is returned in 'csp', if 'csp' is
not NULL.  This function should be called only after FcConfigSubstitute
and FcDefaultSubstitute have been called for 'p'; otherwise the results
will not be correct.

The returned FcFontSet references FcPattern structures which may be shared
by the return value from multiple FcFontSort calls, applications must not
modify these patterns.  Instead, they should be passed, along with 'p' to
FcFontRenderPrepare which combines them into a complete pattern.

The FcFontSet returned by FcFontSort is destroyed by calling FcFontSetDestroy.
@end deftypefun


@node Initialization, FcAtomic, Querying Fonts and Their Properties, Functions
@subsection Initialization

An FcConfig object holds the internal representation of a configuration.
There is a default configuration which applications may use by passing 0 to
any function using the data within an FcConfig.

@deftypefun FcConfig *FcConfigCreate (void)

Creates an empty configuration.
@end deftypefun

@deftypefun void FcConfigDestroy (FcConfig *config)

Destroys a configuration and any data associated with it.  Note that calling
this function with the return value from FcConfigGetCurrent will place the
library in an indeterminate state.
@end deftypefun

@deftypefun FcBool FcConfigSetCurrent (FcConfig *config)

Sets the current default configuration to 'config'.  Implicitly calls
FcConfigBuildFonts if necessary, returning FcFalse if that call fails.
@end deftypefun

@deftypefun FcConfig *FcConfigGetCurrent (void)

Returns the current default configuration.
@end deftypefun

@deftypefun FcBool FcConfigUptoDate (FcConfig *config)

Checks all of the files related to 'config' and returns whether the
in-memory version is in sync with the disk version.
@end deftypefun

@deftypefun FcBool FcConfigBuildFonts (FcConfig *config)

Builds the set of available fonts for the given configuration.  Note that
any changes to the configuration after this call have indeterminate effects.
Returns FcFalse if this operation runs out of memory.
@end deftypefun

@deftypefun FcStrList *FcConfigGetConfigDirs (FcConfig *config)

Returns the list of font directories specified in the configuration files
for 'config'.  Does not include any subdirectories.
@end deftypefun

@deftypefun FcStrList *FcConfigGetFontDirs (FcConfig *config)

Returns the list of font directories in 'config'. This includes the
configured font directories along with any directories below those in the
filesystem.
@end deftypefun

@deftypefun FcStrList *FcConfigGetConfigFiles (FcConfig *config)

Returns the list of known configuration files used to generate 'config'.
Note that this will not include any configuration done with FcConfigParse.
@end deftypefun

@deftypefun char *FcConfigGetCache (FcConfig *config)

Returns the name of the file used to store per-user font information.
@end deftypefun

@deftypefun FcFontSet *FcConfigGetFonts (FcConfig *config, FcSetName set)

Returns one of the two sets of fonts from the configuration as specified 
by 'set'.
@end deftypefun

@deftypefun FcBlanks *FcConfigGetBlanks (FcConfig *config)

Returns the FcBlanks object associated with the given configuration, if no
blanks were present in the configuration, this function will return 0.
@end deftypefun

@deftypefun int FcConfigGetRescanInverval (FcConfig *config)

Returns the interval between automatic checks of the configuration (in
seconds) specified in 'config'.  The configuration is checked during
a call to FcFontList when this interval has passed since the last check.
@end deftypefun

@deftypefun FcBool FcConfigSetRescanInverval (FcConfig *config, int rescanInterval)

Sets the rescan interval; returns FcFalse if an error occurred.
@end deftypefun

@deftypefun FcBool FcConfigAppFontAddFile (FcConfig *config, const char *file)

Adds an application-specific font to the configuration.
@end deftypefun

@deftypefun FcBool FcConfigAppFontAddDir (FcConfig *config, const char *dir)

Scans the specified directory for fonts, adding each one found to the
application-specific set of fonts.
@end deftypefun

@deftypefun void FcConfigAppFontClear (FcConfig *config)

Clears the set of application-specific fonts.
@end deftypefun

These functions provide some control over how the default configuration of
the library is initialized.  (This configuration is normally implicitly
initialized.)

@deftypefun char *FcConfigFilename (const char *name)

Given the specified external entity name, return the associated filename.
This provides applications a way to convert various configuration file
references into filename form. 

A null or empty 'name' indicates that the default configuration file should
be used; which file this references can be overridden with the
FC_CONFIG_FILE environment variable.  Next, if the name starts with '~', it
refers to a file in the current users home directory.  Otherwise if the name
doesn't start with '/', it refers to a file in the default configuration
directory; the built-in default directory can be overridden with the
FC_CONFIG_DIR environment variable.
@end deftypefun

@deftypefun FcConfig *FcInitLoadConfig (void)

Loads the default configuration file and returns the resulting configuration.
Does not load any font information.
@end deftypefun

@deftypefun FcConfig *FcInitLoadConfigAndFonts (void)

Loads the default configuration file and builds information about the
available fonts.  Returns the resulting configuration.
@end deftypefun

@deftypefun FcBool FcInit (void)

Loads the default configuration file and the fonts referenced therein and
sets the default configuration to that result.  Returns whether this
process succeeded or not.  If the default configuration has already
been loaded, this routine does nothing and returns FcTrue.
@end deftypefun

@deftypefun int FcGetVersion (void)

Returns the version number of the library.
@end deftypefun

@deftypefun FcBool FcInitReinitialize (void)

Forces the default configuration file to be reloaded and resets the default
configuration.
@end deftypefun

@deftypefun FcBool FcInitBringUptoDate (void)

Checks the rescan interval in the default configuration, checking the
configuration if the interval has passed and reloading the configuration
when any changes are detected.
@end deftypefun


@node FcAtomic, FreeType-Specific Functions, Initialization, Functions
@subsection FcAtomic

These functions provide a safe way to update config files, allowing ongoing
reading of the old config file while locked for writing and ensuring that a
consistent and complete version of the config file is always available.

@deftypefun FcAtomic * FcAtomicCreate (const FcChar8   *file)

Creates a data structure containing data needed to control access to 'file'.
Writing is done to a separate file.  Once that file is complete, the
original configuration file is atomically replaced so that reading processes
always see a consistent and complete file without the need to lock for
reading.
@end deftypefun

@deftypefun FcBool FcAtomicLock (FcAtomic *atomic)

Attempts to lock the file referenced by 'atomic'.  Returns FcFalse if the
file is locked by another process, else returns FcTrue and leaves the file
locked.
@end deftypefun

@deftypefun FcChar8 *FcAtomicNewFile (FcAtomic *atomic)

Returns the filename for writing a new version of the file referenced
by 'atomic'.
@end deftypefun

@deftypefun FcChar8 *FcAtomicOrigFile (FcAtomic *atomic)

Returns the file refernced by 'atomic'.
@end deftypefun

@deftypefun FcBool FcAtomicReplaceOrig (FcAtomic *atomic)

Replaces the original file referenced by 'atomic' with the new file.
@end deftypefun

@deftypefun void FcAtomicDeleteNew (FcAtomic *atomic)

Deletes the new file.
@end deftypefun

@deftypefun void FcAtomicUnlock (FcAtomic *atomic)

Unlocks the file.
@end deftypefun

@deftypefun void FcAtomicDestroy (FcAtomic *atomic)

Destroys 'atomic'.
@end deftypefun

@node FreeType-Specific Functions, XML-Specific Functions, FcAtomic, Functions
@subsection FreeType-Specific Functions

@example
#include <fontconfig/fcfreetype.h>
@end example

While the fontconfig library doesn't insist that FreeType be used as the
rasterization mechanism for fonts, it does provide some convenience
functions.

@deftypefun FT_UInt FcFreeTypeCharIndex (FT_Face face, FcChar32 ucs4)

Maps a Unicode char to a glyph index.  This function uses information from
several possible underlying encoding tables to work around broken fonts.
As a result, this function isn't designed to be used in performance
sensitive areas; results from this function are intended to be cached by
higher level functions.
@end deftypefun

@deftypefun {FcCharSet *} FcFreeTypeCharSet (FT_Face face, FcBlanks *blanks) Scans a

FreeType face and returns the set of encoded Unicode chars.  This scans
several encoding tables to build as complete a list as possible.  
If 'blanks' is not 0, the glyphs in the font are examined and any blank glyphs
not in 'blanks' are not placed in the returned FcCharSet.
@end deftypefun

@deftypefun {FcPattern *} FcFreeTypeQuery (const char *file, int id, FcBlanks *blanks, int *count)

Constructs a pattern representing the 'id'th font in 'file'.  The number
of fonts in 'file' is returned in 'count'.
@end deftypefun

@node XML-Specific Functions, File and Directory Routines, FreeType-Specific Functions, Functions
@subsection XML-Specific Functions

@deftypefun FcBool FcConfigParseAndLoad (FcConfig *config, const FcChar8 *file, FcBool complain)

Walks the configuration in 'file' and constructs the internal representation
in 'config'.  Any include files referenced from within 'file' will be loaded
with FcConfigLoad and also parsed.  If 'complain' is FcFalse, no warning
will be displayed if 'file' does not exist.
@end deftypefun

@node File and Directory Routines, FcStrSet and FcStrList, XML-Specific Functions, Functions
@subsection File and Directory Routines

@deftypefun FcBool FcFileScan (FcFontSet *set, FcStrSet *dirs, FcFileCache *cache, FcBlanks *blanks, const char *file, FcBool force)

Scans a single file and adds all fonts found to 'set'.  If 'force' is FcTrue,
then the file is scanned even if associated information is found in 'cache'.
If 'file' is a directory, it is added to 'dirs'.
@end deftypefun

@deftypefun FcBool FcDirScan (FcFontSet *set, FcStrSet *dirs, FcFileCache *cache, FcBlanks *blanks, const char *dir, FcBool force)

Scans an entire directory and adds all fonts found to 'set'.  If 'force' is
FcTrue, then the directory and all files within it are scanned even if
information is present in the per-directory cache file or 'cache'.  Any
subdirectories found are added to 'dirs'.
@end deftypefun

@deftypefun FcBool FcDirSave (FcFontSet *set, FcStrSet *dirs, const char *dir)

Creates the per-directory cache file for 'dir' and populates it with the
fonts in 'set' and subdirectories in 'dirs'.
@end deftypefun

@deftypefun FcBool FcDirCacheValid (const FcChar8 *cache_file)

Returns FcTrue if 'cache_file' is no older than the directory containing it,
else FcFalse.
@end deftypefun

@node FcStrSet and FcStrList, String Utilities, File and Directory Routines, Functions
@subsection FcStrSet and FcStrList

A data structure for enumerating strings, used to list directories while
scanning the configuration as directories are added while scanning.

@deftypefun FcStrSet *FcStrSetCreate (void)

Create an empty set.
@end deftypefun

@deftypefun FcBool FcStrSetMember (FcStrSet *set, const FcChar8 *s)

Returns whether 's' is a member of 'set'.
@end deftypefun

@deftypefun FcBool FcStrSetAdd (FcStrSet *set, const FcChar8 *s)

Adds a copy of 's' to 'set'.
@end deftypefun

@deftypefun FcBool FcStrSetAddFilename (FcStrSet *set, const FcChar8 *s)

Adds a copy of 's' to 'set', The copy is created with FcStrCopyFilename
so that leading '~' values are replaced with the value of the HOME
environment variable.
@end deftypefun

@deftypefun FcBool FcStrSetDel (FcStrSet *set, const FcChar8 *s)

Removes 's' from 'set', returning FcTrue if 's' was a member else FcFalse.
@end deftypefun

@deftypefun void FcStrSetDestroy (FcStrSet *set)

Destroys 'set'.
@end deftypefun

@deftypefun FcStrList *FcStrListCreate (FcStrSet *set)

Creates an enumerator to list the strings in 'set'.
@end deftypefun

@deftypefun FcChar8 *FcStrListNext (FcStrList *list)

Returns the next string in 'set'.
@end deftypefun

@deftypefun void FcStrListDone (FcStrList *list)

Destroys the enumerator 'list'.
@end deftypefun

@node String Utilities,  , FcStrSet and FcStrList, Functions
@subsection String Utilities

@deftypefun int FcUtf8ToUcs4 (FcChar8 *src, FcChar32 *dst, int len)

Converts the next Unicode char from 'src' into 'dst' and returns the number
of bytes containing the char.  'src' must be at least 'len' bytes long.
@end deftypefun

@deftypefun int FcUcs4ToUtf8 (FcChar32 src, FcChar8 dst[FC_UTF8_MAX_LEN])

Converts the Unicode char from 'src' into 'dst' and returns the
number of bytes needed to encode the char.
@end deftypefun

@deftypefun FcBool FcUtf8Len (FcChar8 *src, int len, int *nchar, int *wchar)

Counts the number of Unicode chars in 'len' bytes of 'src'.  Places that
count in 'nchar'.  'wchar' contains 1, 2 or 4 depending on the number of
bytes needed to hold the largest unicode char counted.  The return value
indicates whether 'src' is a well-formed UTF8 string.
@end deftypefun

@deftypefun int FcUtf16ToUcs4 (FcChar8 *src, FcEndian endian, FcChar32 *dst, int len)

Converts the next Unicode char from 'src' into 'dst' and returns the
number of bytes containing the char. 'src' must be at least 'len' bytes
long.  Bytes of 'src' are combined into 16-bit units according to 'endian'.
@end deftypefun

@deftypefun FcBool FcUtf16Len (FcChar8 *src, FcEndian endian, int len, int *nchar, int *wchar)

Counts the number of Unicode chars in 'len' bytes of 'src'.  Bytes of 'src'
are combined into 16-bit units according to 'endian'.  Places that
count in 'nchar'.  'wchar' contains 1, 2 or 4 depending on the number of
bytes needed to hold the largest unicode char counted.  The return value
indicates whether 'string' is a well-formed UTF16 string.
@end deftypefun

@deftypefun FcChar8 *FcStrCopy (const FcChar8 *s)

Allocates memory, copies 's' and returns the resulting buffer.  Yes, this
is 'strdup', but that function isn't available on every platform.
@end deftypefun

@deftypefun FcChar8 *FcStrCopyFilename (const FcChar8 *s)

Just like FcStrCopy except that it converts any leading '~' characters 
in 's' to the value of the HOME environment variable.
@end deftypefun

@deftypefun int FcStrCmpIgnoreCase (const char *s1, const char *s2)

Returns the usual <0, 0, >0 result of comparing 's1' and 's2'.  This test
is case-insensitive in the ASCII range and will operate properly with UTF8
encoded strings, although it does not check for well formed strings.
@end deftypefun

@deftypefun FcChar8 *FcStrDirname (const FcChar8 *file)

Returns the directory containing 'file'.
@end deftypefun

@deftypefun FcChar8 *FcStrBasename (const FcChar8 *file)

Returns the filename of 'file' stripped of any leading directory names.
@end deftypefun

@node Configuration File Format, Files, The fontconfig API, Top
@chapter Configuration File Format

Configuration files for fontconfig are stored in XML format; this
format 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
@samp{fonts.dtd}; this is normally stored in the default font configuration
directory (@file{/etc/fonts}).  Each configuration file should contain the
following structure:

@example
	<?xml version="1.0"?>
	<!DOCTYPE fontconfig SYSTEM "fonts.dtd">
	<fontconfig>
	...
	</fontconfig>
@end example

@table @samp
@item <fontconfig>
This is the top level element for a font configuration and can contain
@samp{<dir>}, @samp{<cache>}, @samp{<include>}, @samp{<match>} and @samp{<alias>} elements in any order.

@item <dir>
This element contains a directory name which will be scanned for font files
to include in the set of available fonts.  The scan does not recurse into
subdirectories.

@item <cache>
This element contains a file name for the per-user cache of font
information.  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).

@item <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 warning message from the library.

@item <config>
This element provides a place to consolidate additional configuration
information.  @samp{<config>} can contain @samp{<blank>} and @samp{<rescan>} elements in any
order.

@item <blank>
Fonts often include "broken" glyphs which appear in the encoding but are
drawn as blanks on the screen.  Within the @samp{<blank>} element, place each
Unicode characters which is supposed to be blank in an @samp{<int>} element.
Characters outside of this set which are drawn as blank will be elided from
the set of characters supported by the font.

@item <rescan>
The @samp{<rescan>} element holds an @samp{<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 interval passes.

@item <match target="pattern">
This element holds first a (possibly empty) list of @samp{<test>} elements and then
a (possibly empty) list of @samp{<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.

@item <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.

@item <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 @samp{<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:

@example
Mode	Operation with match	Operation without match

"assign"	Replace matching value		Replace all values
"assign_replace"	Replace all values	Replace all values
"prepend"	Insert before matching value	Insert at head of list
"prepend_first"	Insert at head of list		Insert at head of list
"append"	Append after matching value	Append at end of list
"append_last"	Append at end of list		Append at end of list
@end example

@item <int>
@itemx <double>
@itemx <string>
@itemx <bool>
These elements hold a single value of the indicated type.  @samp{<bool>} elements
hold either true or false.

@item <matrix>

This element holds the four @samp{<double>} elements of an affine transformation.

@item <name>
Holds a property name.  Evaluates to the first value from the property of
the font, not the pattern.

@item <const>
Holds the name of a constant; these are always integers and serve as
symbolic names for common font values:

@example
Constant        Property        CPP symbol

light           weight          FC_WEIGHT_LIGHT
medium          weight          FC_WEIGHT_MEDIUM
demibold        weight          FC_WEIGHT_DEMIBOLD
bold            weight          FC_WEIGHT_BOLD
black           weight          FC_WEIGHT_BLACK
roman           slant           FC_SLANT_ROMAN
italic          slant           FC_SLANT_ITALIC
oblique         slant           FC_SLANT_OBLIQUE
proportional    spacing         FC_PROPORTIONAL
mono            spacing         FC_MONO
charcell        spacing         FC_CHARCELL
unknown         rgba            FC_RGBA_UNKNOWN
rgb             rgba            FC_RGBA_RGB
bgr             rgba            FC_RGBA_BGR
vrgb            rgba            FC_RGBA_VRGB
vbgr            rgba            FC_RGBA_VBGR
none            rgba            FC_RGBA_NONE
@end example

@item <or>
@itemx <and>
@itemx <plus>
@itemx <minus>
@itemx <times>
@itemx <divide>
These elements perform the specified operation on a list of expression
elements.  @samp{<or>} and @samp{<and>} are boolean, not bitwise.

@item <eq>
@itemx <not_eq>
@itemx <less>
@itemx <less_eq>
@itemx <more>
@itemx <more_eq>
These elements compare two values, producing a boolean result.

@item <not>
Inverts the boolean sense of its one expression element

@item <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.

@item <alias>
Alias elements provide a shorthand notation for the set of common match
operations needed to substitute one font family for another.  They contain a
@samp{<family>} element followed by optional @samp{<prefer>}, @samp{<accept>} and @samp{<default>}
elements.  Fonts matching the @samp{<family>} element are edited to prepend the
list of @samp{<prefer>}ed families before the matching @samp{<family>}, append the
@samp{<accept>}able families after the matching @samp{<family>} and append the @samp{<default>}
families to the end of the family list.

@item <family>
Holds a single font family name

@item <prefer>
@itemx <accept>
@itemx <default>
These each hold a list of @samp{<family>} elements to be used by the @samp{<alias>}
element.
@end table

@menu
* Example System Configuration File::  
* Example User Configuration File::  
@end menu

@node Example System Configuration File, Example User Configuration File, Configuration File Format, Configuration File Format
@section Example System Configuration File

This is an example of a system-wide configuration file:

@example
<?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>
@end example

@node Example User Configuration File,  , Example System Configuration File, Configuration File Format
@section Example User Configuration File

This is an example of a per-user configuration file that lives in
@file{~/.fonts.conf}:

@example
<?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>
@end example

@node Files, Authors, Configuration File Format, Top
@chapter Files

@table @file
@item fonts.dtd 
is a DTD that describes the format of the configuration files.

@item fonts.conf
is the default system-wide font configuration file.  It
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, with DTD @file{fonts.dtd}.

@item local.conf
is the conventional default location for local font configuration.  It
is sourced by the default system-wide fonts.conf file. 
Note that the normal 'make install' procedure for XFree86 is to
replace any existing fonts.conf file with the new version.  Place
any local customizations in local.conf which this file references.
It is in xml format, with DTD @file{fonts.dtd}.

@item ~/.fonts.conf
is the conventional location for per-user font configuration, although the
actual location is specified in the global fonts.conf file.
It is in xml format, with DTD @file{fonts.dtd}.

@item fonts.cache-*
is found in each font directory where fonts were found.  This file is
automatically maintained by fontconfig.  It is a flat text table, and
should be treated as opaque.

@item ~/.fonts.cache-*
is the conventional repository of font information that isn't found in the
per-directory caches.  This file is automatically maintained by fontconfig.
It is a flat text table, and should be treated as opaque.
@end table

@node Authors,  , Files, Top
@chapter Authors

@table @strong
@item Keith Packard
member of the XFree86 Project, Inc.

@item Stephen J. Turnbull
member of the XEmacs Project
@end table

@bye

@c Local variables:
@c mode: texinfo
@c End:

@c  arch-tag: 108A3E8B-1CE1-11D9-9957-000A959E994E

@c end of fontconfig.texi
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