diff options
| -rw-r--r-- | .gitignore | 4 | ||||
| -rw-r--r-- | Makefile.am | 21 | ||||
| -rw-r--r-- | configure.ac | 12 | ||||
| -rw-r--r-- | doc/fontlib.css | 46 | ||||
| -rw-r--r-- | doc/fontlib.ms | 403 | ||||
| -rw-r--r-- | doc/fontlib.xml | 660 | ||||
| -rw-r--r-- | doc/fontlib.xsl | 38 |
7 files changed, 781 insertions, 403 deletions
@@ -28,3 +28,7 @@ xfont.pc libXfont-*.tar.* ChangeLog tags +doc/fontlib.txt +doc/fontlib.html +doc/fontlib.ps +doc/fontlib.pdf diff --git a/Makefile.am b/Makefile.am index 1da055b..b90a7ad 100644 --- a/Makefile.am +++ b/Makefile.am @@ -52,3 +52,24 @@ ChangeLog: dist-hook: ChangeLog +# Developer documentation - not installed on system +EXTRA_DIST += doc/fontlib.xml doc/fontlib.xsl doc/fontlib.css + +if MAKE_DEVEL_DOCS +if HAVE_XMLTO +noinst_DATA = doc/fontlib.txt doc/fontlib.html $(srcdir)/doc/fontlib.css +CLEANFILES = doc/fontlib.txt doc/fontlib.html doc/fontlib.pdf doc/fontlib.ps + +doc/fontlib.txt: $(srcdir)/doc/fontlib.xml $(srcdir)/doc/fontlib.xsl + $(AM_V_GEN)$(XMLTO) -m $(srcdir)/doc/fontlib.xsl -o doc txt $(srcdir)/doc/fontlib.xml + +doc/fontlib.html: $(srcdir)/doc/fontlib.xml $(srcdir)/doc/fontlib.xsl + $(AM_V_GEN)$(XMLTO) -m $(srcdir)/doc/fontlib.xsl -o doc xhtml-nochunks $(srcdir)/doc/fontlib.xml + +doc/fontlib.pdf: $(srcdir)/doc/fontlib.xml $(srcdir)/doc/fontlib.xsl + $(AM_V_GEN)$(XMLTO) -m $(srcdir)/doc/fontlib.xsl -o doc pdf $(srcdir)/doc/fontlib.xml + +doc/fontlib.ps: $(srcdir)/doc/fontlib.xml $(srcdir)/doc/fontlib.xsl + $(AM_V_GEN)$(XMLTO) -m $(srcdir)/doc/fontlib.xsl -o doc ps $(srcdir)/doc/fontlib.xml +endif HAVE_XMLTO +endif MAKE_DEVEL_DOCS diff --git a/configure.ac b/configure.ac index bd096f4..5c0a4a5 100644 --- a/configure.ac +++ b/configure.ac @@ -49,6 +49,18 @@ PKG_PROG_PKG_CONFIG XORG_DEFAULT_OPTIONS +# xmlto is used to convert doc/fontlib.xml from DocBook to PDF/HTML +AC_ARG_VAR([XMLTO], [Path to xmlto command]) +AC_PATH_PROG([XMLTO], [xmlto]) +AM_CONDITIONAL([HAVE_XMLTO], [test "x$XMLTO" != "x"]) + +# Option to enable support for building developer internals docs +AC_ARG_ENABLE(devel-docs, + AS_HELP_STRING([--enable-devel-docs], + [Build internals documentation for developers (default: enabled)]), + [DEVEL_DOCS=$enableval], [DEVEL_DOCS=yes]) +AM_CONDITIONAL([MAKE_DEVEL_DOCS], [test "x$DEVEL_DOCS" = "xyes"]) + # Look for headers AC_CHECK_HEADERS([endian.h poll.h sys/poll.h]) AC_CHECK_FUNCS([poll]) diff --git a/doc/fontlib.css b/doc/fontlib.css new file mode 100644 index 0000000..137200f --- /dev/null +++ b/doc/fontlib.css @@ -0,0 +1,46 @@ +/* Copyright 2009 Sun Microsystems, Inc. All rights reserved. + * + * Permission is hereby granted, free of charge, to any person obtaining a + * copy of this software and associated documentation files (the + * "Software"), to deal in the Software without restriction, including + * without limitation the rights to use, copy, modify, merge, publish, + * distribute, and/or sell copies of the Software, and to permit persons + * to whom the Software is furnished to do so, provided that the above + * copyright notice(s) and this permission notice appear in all copies of + * the Software and that both the above copyright notice(s) and this + * permission notice appear in supporting documentation. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS + * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF + * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT + * OF THIRD PARTY RIGHTS. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR + * HOLDERS INCLUDED IN THIS NOTICE BE LIABLE FOR ANY CLAIM, OR 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. + * + * Except as contained in this notice, the name of a copyright holder + * shall not be used in advertising or otherwise to promote the sale, use + * or other dealings in this Software without prior written authorization + * of the copyright holder. + */ + +.structname, .property, .errorname, .function, .parameter, .filename { + font-family: monospace; +} + +h1, .author, .pubdate { + text-align: center; +} + +.legalnotice { + text-align: justify; + font-size: small; + font-style: italic; +} + +.warning { + border: 1px solid red; + background: yellow; +} diff --git a/doc/fontlib.ms b/doc/fontlib.ms deleted file mode 100644 index f4f3b07..0000000 --- a/doc/fontlib.ms +++ /dev/null @@ -1,403 +0,0 @@ -.\" Copyright 1993 Network Computing Devices -.\" -.\" 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 Network Computing Devices -.\" not be used in advertising or -.\" publicity pertaining to distribution of the software without specific, -.\" written prior permission. Network Computing Devices makes -.\" no representations about the -.\" suitability of this software for any purpose. It is provided "as is" -.\" without express or implied warranty. -.\" -.\" Copyright 1993, 1994 X Consortium -.\" -.\" Permission is hereby granted, free of charge, to any person obtaining -.\" a copy of this software and associated documentation files (the -.\" ``Software''), to deal in the Software without restriction, including -.\" without limitation the rights to use, copy, modify, merge, publish, -.\" distribute, sublicense, and/or sell copies of the Software, and to -.\" permit persons to whom the Software is furnished to do so, subject to -.\" the following conditions: -.\" -.\" The above copyright notice and this permission notice shall be -.\" included in all copies or substantial portions of the Software. -.\" -.\" THE SOFTWARE IS PROVIDED ``AS IS'', WITHOUT WARRANTY OF ANY KIND, -.\" EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF -.\" MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. -.\" IN NO EVENT SHALL THE X CONSORTIUM BE LIABLE FOR ANY CLAIM, DAMAGES OR -.\" OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, -.\" ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR -.\" OTHER DEALINGS IN THE SOFTWARE. -.\" -.\" Except as contained in this notice, the name of the X Consortium shall -.\" not be used in advertising or otherwise to promote the sale, use or -.\" other dealings in this Software without prior written authorization -.\" from the X Consortium. -.ps 12 -.nr PS 12 -.de Cs -.IP -.nf -.ft C -.. -.de Ce -.ft P -.fi -.. -.\" $Xorg: fontlib.ms,v 1.3 2000/08/17 19:42:42 cpqbld Exp $ -.EF 'Font Library Interface'- % -'July 27, 1991' -.OF 'Font Library Interface'- % -'July 27, 1991' -.EH '''' -.OH '''' -.TL -The X Font Library -.AU -Keith Packard -.AI -MIT X Consortium -.AU -David Lemke -.AI -Network Computing Devices -.LP -This document describes the data structures and interfaces for using the X -Font library. It is intended as a reference for programmers building X -and Font servers. You may want to refer to the following documents: -.IP \(bu 5 -"Definition of the Porting Layer for the X v11 Sample Server" for a -discussion on how this library interacts with the X server -.IP \(bu 5 -"Font Server Implementation Overview" which discusses the design of the font -server. -.IP \(bu 5 -"Bitmap Distribution Format" which covers the contents of the bitmap font -files which this library reads; although the library is capable of reading -other formats as well, including non-bitmap fonts. -.IP \(bu 5 -"The X Font Service Protocol" for a description of the constraints placed on -the design by including support for this font service mechanism. -.LP -This document assumes the reader is familiar with the X server design, the -X protocol as it relates to fonts and the C programming language. As with -most MIT produced documentation, this relies heavily on the source code, so -have a listing handy. -.NH 1 -Requirements for the Font library -.LP -To avoid miles of duplicate code in the X server, the font server and the -various font manipulation tools, the font library should provide interfaces -appropriate for all of these tasks. In particular, the X server and font -server should be able to both use the library to access disk based fonts, -and to communicate with a font server. By providing a general library, we -hoped to avoid duplicating code between the X server and font server. -.LP -Another requirement is that the X server (or even a font server) be able to -continue servicing requests from other clients while awaiting a response -from the font server on behalf of one client. This is the strongest -requirement placed on the font library, and has warped the design in curious -ways. Because both the X server and font server are single threaded, the -font library must not suspend internally, rather it returns an indication of -suspension to the application which continues processing other things, until -the font data is ready, at which time it restarts the suspended request. -.LP -Because the code for reading and manipulating bitmap font data is used by -the font applications "mkfontdir" and "bdftopcf", the font library includes -bitmap-font specific interfaces which those applications use, instead of the -more general interfaces used by the X and font servers, which are unaware of -the source of the font data. These routines will be refered to as the -bitmap font access methods. -.NH 1 -General Font Library Interface details. -.LP -To avoid collision between the #define name space for errors, the Font -library defines a new set of return values: -.Cs -#define AllocError 80 -#define StillWorking 81 -#define FontNameAlias 82 -#define BadFontName 83 -#define Suspended 84 -#define Successful 85 -#define BadFontPath 86 -#define BadCharRange 87 -#define BadFontFormat 88 -#define FPEResetFailed 89 -.Ce -.LP -Whenever a routine returns \fBSuspended\fP, the font library will notify the -caller (via the ClientSignal interface described below) who should then -reinvoke the same routine again with the same arguments. -.NH 1 -Font Path Elements -.LP -At the center of the general font access methods used by X and fs is the -Font Path Element data structure. Like most structures in the X server, -this contains a collection of data and some function pointers for -manipulating this data: -.Cs -/* External view of font paths */ -typedef struct _FontPathElement { - int name_length; - char *name; - int type; - int refcount; - pointer private; -} FontPathElementRec, *FontPathElementPtr; - -typedef struct _FPEFunctions { - int (*name_check) ( /* name */ ); - int (*init_fpe) ( /* fpe */ ); - int (*reset_fpe) ( /* fpe */ ); - int (*free_fpe) ( /* fpe */ ); - int (*open_font) ( /* client, fpe, flags, - name, namelen, format, - fid, ppfont, alias */ ); - int (*close_font) ( /* pfont */ ); - int (*list_fonts) ( /* client, fpe, pattern, - patlen, maxnames, paths */ ); - int (*start_list_fonts_with_info) ( - /* client, fpe, name, namelen, - maxnames, data */ ); - int (*list_next_font_with_info) ( - /* client, fpe, name, namelen, - info, num, data */ ); - int (*wakeup_fpe) ( /* fpe, mask */ ); - int (*client_died) ( /* client, fpe */ ); -} FPEFunctionsRec, FPEFunctions; -.Ce -.LP -The function pointers are split out from the data structure to save memory; -additionally, this avoids any complications when initializing the data -structure as there would not be any way to discover the appropriate function -to call (a chicken and egg problem). -.LP -When a font path type is initialized, it passes the function pointers to the -server which are then stored in an FPEFunctionsRec. Each function is -described below in turn. -.NH 2 -(*name_check) -.LP -Each new font path member is passed to this function; if the return value -is Successful, then the FPE recognises the format of the string. This does -not guarantee that the FPE will be able to successfully use this member. -For example, the disk-based font directory file "fonts.dir" may be -corrupted, this will not be detected until the font path is initialized. -This routine never returns \fBSuspended\fP. -.NH 2 -(*init_fpe) -.LP -Initialize a new font path element. This function prepares a new font path -element for other requests: the disk font routine reads the "fonts.dir" and -"fonts.alias" files into the internal format, while the font server routine -connects to the requested font server and prepares for using it. This -routine returns Successful if everything went OK, otherwise the return value -indicates the source of the problem. This routine never returns \fBSuspended\fP. -.NH 2 -(*reset_fpe) -.LP -When the X font path is reset, and some of the new members are also in the -old font path, this function is called to reinitialize those FPEs. This -routine returns Successful if everything went OK. It returns FPEResetFailed -if (for some reason) the reset failed, and the caller should remove the old -FPE and simply create a new one in its place. This is used by the -disk-based fonts routine as resetting the internal directory structures -would be more complicated than simply having destroying the old and creating -a new. -.NH 2 -(*free_fpe) -.LP -When the server is finished with an FPE, this function is called to dispose -of any internal state. It should return Successful, unless something -terrible happens. -.NH 2 -(*open_font) -.LP -This routine requests that a font be opened. The client argument is used -by the font library only in connection with suspending/restarting the -request. The flags argument specifies some behaviour for the library and can -be any of: -.Cs -/* OpenFont flags */ -#define FontLoadInfo 0x0001 -#define FontLoadProps 0x0002 -#define FontLoadMetrics 0x0004 -#define FontLoadBitmaps 0x0008 -#define FontLoadAll 0x000f -#define FontOpenSync 0x0010 -.Ce -.LP -The various fields specify which portions of the font should be loaded at -this time. When FontOpenSync is specified, this routine will not return -until all of the requested portions are loaded. Otherwise, this routine may -return \fBSuspended\fP. When the presented font name is actually an alias -for some other font name, FontName Alias is returned, and the actual font -name is stored in the location pointed to by the \fIalias\fP argument as a -null-terminated string. -.NH 2 -(*close_font) -.LP -When the server is finished with a font, this routine disposes of any -internal state and frees the font data structure. -.NH 2 -(*list_fonts) -.LP -The \fIpaths\fP argument is a data structure which will be filled with all -of the font names from this directory which match the specified pattern. At -most \fImaxnames\fP will be added. This routine may return \fBSuspended\fP. -.NH 2 -(*start_list_fonts_with_info) -.LP -This routine sets any internal state for a verbose listing of all fonts -matching the specified pattern. This routine may return \fBSuspended\fP. -.NH 2 -(*list_next_font_with_info) -.LP -To avoid storing huge amounts of data, the interface for ListFontsWithInfo -allows the server to get one reply at a time and forward that to the -client. When the font name returned is actually an alias for some other -font, \fBFontNameAlias\fP will be returned. The actual font name is return -instead, and the font alias which matched the pattern is returned in the -location pointed to by data as a null-terminated string. The caller can -then get the information by recursively listing that font name with a -maxnames of 1. When \fBSuccessful\fP is returned, the matching font name is -returned, and a FontInfoPtr is stored in the location pointed to by -\fIdata\fP. \fIData\fP must be initialized with a pointer to a FontInfoRec -allocated by the caller. When the pointer pointed to by \fIdata\fP is not -left pointing at that storage, the caller mustn't free the associated -property data. This routine may return \fBSuspended\fP. -.NH 2 -(*wakeup_fpe) -.LP -Whenever an FPE function has returned Suspended, this routine is called -whenever the application wakes up from waiting for input (from select(2)). -This mask argument should be the value returned from select(2). -.NH 2 -(*client_died) -.LP -When an FPE function has returned \fBSuspended\fP and the associated client -is being destroyed, this function allows the font library to dispose of any -state associated with that client. -.NH 1 -Fonts -.LP -The data structure which actually contains the font information has changed -significantly since previous releases; it now attempts to hide the actual -storage format for the data from the application, providing accessor -functions to get at the data. This allows a range of internal details for -different font sources. The structure is split into two pieces, so that -ListFontsWithInfo can share information from the font when it has been -loaded. The FontInfo structure, then, contains only information germane to -LFWI. -.Cs -typedef struct _FontInfo { - unsigned short firstCol; /* range of glyphs for this font */ - unsigned short lastCol; - unsigned short firstRow; - unsigned short lastRow; - unsigned short defaultCh; /* default character index */ - unsigned int noOverlap:1; /* no combination of glyphs overlap */ - unsigned int terminalFont:1; /* Character cell font */ - unsigned int constantMetrics:1; /* all metrics are the same */ - unsigned int constantWidth:1; /* all character widths are the same*/ - unsigned int inkInside:1; /* all ink inside character cell */ - unsigned int inkMetrics:1; /* font has ink metrics */ - unsigned int allExist:1; /* no missing chars in range */ - unsigned int drawDirection:2; /* left-to-right/right-to-left*/ - unsigned int cachable:1; /* font needn't be opened each time*/ - unsigned int anamorphic:1; /* font is strangely scaled */ - short maxOverlap; /* maximum overlap amount */ - short pad; /* unused */ - xCharInfo maxbounds; /* glyph metrics maximums */ - xCharInfo minbounds; /* glyph metrics minimums */ - xCharInfo ink_maxbounds; /* ink metrics maximums */ - xCharInfo ink_minbounds; /* ink metrics minimums */ - short fontAscent; /* font ascent amount */ - short fontDescent; /* font descent amount */ - int nprops; /* number of font properties */ - FontPropPtr props; /* font properties */ - char *isStringProp; /* boolean array */ -} FontInfoRec, *FontInfoPtr; -.Ce -.LP -The font structure, then, contains a font info record, the format of the -bits in each bitmap and the functions which access the font records (which -are stored in an opaque format hung off of fontPrivate). -.Cs -typedef struct _Font { - int refcnt; - FontInfoRec info; - char bit; /* bit order: LSBFirst/MSBFirst */ - char byte; /* byte order: LSBFirst/MSBFirst */ - char glyph; /* glyph pad: 1, 2, 4 or 8 */ - char scan; /* glyph scan unit: 1, 2 or 4 */ - fsBitmapFormat format; /* FS-style format (packed) */ - int (*get_glyphs) ( /* font, count, chars, encoding, count, glyphs */ ); - int (*get_metrics) ( /* font, count, chars, encoding, count, glyphs */ ); - int (*get_bitmaps) (/* client, font, flags, format, - flags, nranges, ranges, data_sizep, - num_glyphsp, offsetsp, glyph_datap, - free_datap */ ); - int (*get_extents) (/* client, font, flags, nranges, - ranges, nextentsp, extentsp */); - void (*unload_font) ( /* font */ ); - FontPathElementPtr fpe; /* FPE associated with this font */ - pointer svrPrivate; /* X/FS private data */ - pointer fontPrivate; /* private to font */ - pointer fpePrivate; /* private to FPE */ - int maxPrivate; /* devPrivates (see below) */ - pointer *devPrivates; /* ... */ -} FontRec, *FontPtr; -.Ce -.LP -Yes, there are several different private pointers in the Font structure; they -were added haphazardly until the devPrivate pointers were added. Future -releases may remove some (or all) of the specific pointers, leaving only the -devPrivates mechanism. -.LP -There are two similar interfaces implemented - get_glyphs/get_metrics and -get_bitmaps/get_extents. Too little time caused the font-server specific -interfaces to be placed in the font library (and portions duplicated in each -renderer) instead of having them integrated into the font server itself. -This may change. The X server uses only get_glyphs/get_metrics, and those -will not change dramatically. Each of the routines is described below -.NH 2 -(*get_glyphs) -.LP -This routine returns CharInfoPtrs for each of the requested characters in -the font. If the character does not exist in the font, the default -character will be returned, unless no default character exists in which case -that character is skipped. Thus, the number of glyphs returned will not -always be the same as the number of characters passed in. -.NH 2 -(*get_metrics) -.LP -This is similar to (*get_glyphs) except that pointers to xCharInfo -structures are returned, and, if the font has ink metrics, those are -returned instead of the bitmap metrics. -.NH 2 -(*get-bitmaps) -.LP -This packs the glyph image data in the requested format and returns it. The -ranges/nranges argument specify the set of glyphs from the font to pack -together. -.NH 2 -(*get_extents) -.LP -This returns the metrics for the specified font from the specified ranges. -.LP -.NH 2 -(*unload_font) -.LP -This is called from the FPE routine (*close_font), and so should not ever be -called from the application. -.NH 2 -maxPrivate -.LP -When initializing a new font structure, maxPrivate should be set to -1 -so that the FontSetPrivate() macro works properly with an index of 0. -Initializing maxPrivate to 0 can cause problems if the server tries to set -something at index 0. diff --git a/doc/fontlib.xml b/doc/fontlib.xml new file mode 100644 index 0000000..8b7245e --- /dev/null +++ b/doc/fontlib.xml @@ -0,0 +1,660 @@ +<?xml version="1.0" encoding="UTF-8" ?> +<!DOCTYPE article PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN" + "http://www.oasis-open.org/docbook/xml/4.4/docbookx.dtd" > +<!-- lifted from troff+ms by doclifter --> +<!-- previous version was in xorg-docs/specs/Xserver/fontlib.ms --> + + <article id='fontlibms'> +<!-- .ps 12 --> +<!-- $Xorg: fontlib.ms,v 1.3 2000/08/17 19:42:42 cpqbld Exp $ --> +<!-- .EF 'Font Library Interface'\- % \-'July 27, 1991' --> +<!-- .OF 'Font Library Interface'\- % \-'July 27, 1991' --> +<!-- .EH '''' --> +<!-- .OH '''' --> +<!-- body begins here --> + <articleinfo> + <title> + The X Font Library + </title> + <pubdate>July 27, 1991</pubdate> + <authorgroup> + <author> + <firstname>Keith</firstname> + <surname>Packard</surname> + <affiliation> + <orgname>MIT X Consortium</orgname> + </affiliation> + </author> + <author> + <firstname>David</firstname> + <surname>Lemke</surname> + <affiliation> + <orgname>Network Computing Devices</orgname> + </affiliation> + </author> + </authorgroup> + <legalnotice> + <para> + Copyright 1993 <orgname>Network Computing Devices</orgname> + </para> + <para> + 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 Network Computing + Devices not be used in advertising or publicity pertaining + to distribution of the software without specific, written + prior permission. Network Computing Devices makes no + representations about the suitability of this software for + any purpose. It is provided “as is” without + express or implied warranty. + </para> + <para> + Copyright 1993, 1994 <orgname>X Consortium</orgname> + </para> + <para> + Permission is hereby granted, free of charge, to any person + obtaining a copy of this software and associated + documentation files (the “Software”), to deal in the + Software without restriction, including without limitation + the rights to use, copy, modify, merge, publish, distribute, + sublicense, and/or sell copies of the Software, and to + permit persons to whom the Software is furnished to do so, + subject to the following conditions: + </para><para> + The above copyright notice and this permission notice shall be + included in all copies or substantial portions of the Software. + </para><para> + THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY + OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO + THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR + PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE X + CONSORTIUM BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR + OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE + SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. + </para><para> + Except as contained in this notice, the name of the X + Consortium shall not be used in advertising or otherwise to + promote the sale, use or other dealings in this Software + without prior written authorization from the X Consortium. + </para> + </legalnotice> + </articleinfo> + + <warning> + <para> + This document has not been updated since X11R6, and is likely + to be somewhat out of date for the current libXfont. + </para> + </warning> + + <para> + This document describes the data structures and interfaces for + using the X Font library. It is intended as a reference for + programmers building X and Font servers. You may want to refer + to the following documents: + </para> + + <itemizedlist> + <listitem> + <para> + <citetitle pubwork="article">Definition of the Porting Layer for + the X v11 Sample Server</citetitle> for a discussion on how this + library interacts with the X server + </para> + </listitem> + <listitem> + <para> + <citetitle pubwork="article">Font Server Implementation + Overview</citetitle> which discusses the design of the font + server. + </para> + </listitem> + <listitem> + <para> + <citetitle pubwork="article">Bitmap Distribution Format</citetitle> + which covers the contents of the bitmap font files which this + library reads; although the library is capable of reading other + formats as well, including non-bitmap fonts. + </para> + </listitem> + <listitem> + <para> + <citetitle pubwork="article">The X Font Service Protocol</citetitle> + for a description of the constraints placed on the design by + including support for this font service mechanism. + </para> + </listitem> + </itemizedlist> + + <para> + This document assumes the reader is familiar with the X server design, + the X protocol as it relates to fonts and the C programming language. + As with most MIT produced documentation, this relies heavily on the + source code, so have a listing handy. + </para> + + <sect1 id='requirements_for_the_font_library'> + <title> + Requirements for the Font library + </title> + + <para> + To avoid miles of duplicate code in the X server, the font server + and the various font manipulation tools, the font library should + provide interfaces appropriate for all of these tasks. In + particular, the X server and font server should be able to both + use the library to access disk based fonts, and to communicate + with a font server. By providing a general library, we hoped to + avoid duplicating code between the X server and font server. + </para> + + <para> + Another requirement is that the X server (or even a font server) + be able to continue servicing requests from other clients while + awaiting a response from the font server on behalf of one client. + This is the strongest requirement placed on the font library, and + has warped the design in curious ways. Because both the X server + and font server are single threaded, the font library must not + suspend internally, rather it returns an indication of suspension + to the application which continues processing other things, until + the font data is ready, at which time it restarts the suspended + request. + </para> + + <para> + Because the code for reading and manipulating bitmap font data is + used by the font applications <command>mkfontdir</command> and + <command>bdftopcf</command>, the font library includes + bitmap-font specific interfaces which those applications use, + instead of the more general interfaces used by the X and font + servers, which are unaware of the source of the font data. + These routines will be refered to as the bitmap font access + methods. + </para> + + </sect1> + + <sect1 id='general_font_library_interface_details'> + <title> + General Font Library Interface details. + </title> + + <para> + To avoid collision between the #define name space for errors, the Font + library defines a new set of return values: + </para> + + <programlisting remap='.nf'> +#define AllocError 80 +#define StillWorking 81 +#define FontNameAlias 82 +#define BadFontName 83 +#define Suspended 84 +#define Successful 85 +#define BadFontPath 86 +#define BadCharRange 87 +#define BadFontFormat 88 +#define FPEResetFailed 89 + </programlisting> <!-- .fi --> + + <para> + Whenever a routine returns <errorname>Suspended</errorname>, + the font library will notify the caller (via the ClientSignal + interface described below) who should then reinvoke the same routine + again with the same arguments. + </para> + + </sect1> + + <sect1 id='font_path_elements'> + <title> + Font Path Elements + </title> + + <para> + At the center of the general font access methods used by X and + <command>xfs</command> is the Font Path Element data structure. + Like most structures in the X server, this contains a collection + of data and some function pointers for manipulating this data: + </para> + + <programlisting remap='.nf'> +/* External view of font paths */ +typedef struct _FontPathElement { + int name_length; + char *name; + int type; + int refcount; + pointer private; +} FontPathElementRec, *FontPathElementPtr; + +typedef struct _FPEFunctions { + int (*name_check) ( /* name */ ); + int (*init_fpe) ( /* fpe */ ); + int (*reset_fpe) ( /* fpe */ ); + int (*free_fpe) ( /* fpe */ ); + int (*open_font) ( /* client, fpe, flags, + name, namelen, format, + fid, ppfont, alias */ ); + int (*close_font) ( /* pfont */ ); + int (*list_fonts) ( /* client, fpe, pattern, + patlen, maxnames, paths */ ); + int (*start_list_fonts_with_info) ( + /* client, fpe, name, namelen, + maxnames, data */ ); + int (*list_next_font_with_info) ( + /* client, fpe, name, namelen, + info, num, data */ ); + int (*wakeup_fpe) ( /* fpe, mask */ ); + int (*client_died) ( /* client, fpe */ ); +} FPEFunctionsRec, FPEFunctions; + </programlisting> <!-- .fi --> + + <para> + The function pointers are split out from the data structure to + save memory; additionally, this avoids any complications when + initializing the data structure as there would not be any way + to discover the appropriate function to call (a chicken and + egg problem). + </para> + + <para> + When a font path type is initialized, it passes the function + pointers to the server which are then stored in an + <structname>FPEFunctionsRec</structname>. Each function is + described below in turn. + </para> + + <sect2 id='name_check'> + <title> + (*name_check) + </title> + + <para> + Each new font path member is passed to this function; if + the return value is <errorname>Successful</errorname>, then + the FPE recognises the format of the string. This does not + guarantee that the FPE will be able to successfully use this + member. For example, the disk-based font directory file + <filename>fonts.dir</filename> may be corrupted, this will + not be detected until the font path is initialized. This + routine never returns <errorname>Suspended</errorname>. + </para> + </sect2> + + <sect2 id='init_fpe'> + <title> + (*init_fpe) + </title> + + <para> + Initialize a new font path element. This function prepares + a new font path element for other requests: the disk font + routine reads the <filename>fonts.dir</filename> and + <filename>fonts.alias</filename> files into the internal + format, while the font server routine connects to the + requested font server and prepares for using it. This + routine returns <errorname>Successful</errorname> if + everything went OK, otherwise the return value indicates the + source of the problem. This routine never returns + <errorname>Suspended</errorname>. + </para> + </sect2> + + <sect2 id='reset_fpe'> + <title> + (*reset_fpe) + </title> + + <para> + When the X font path is reset, and some of the new members + are also in the old font path, this function is called to + reinitialize those FPEs. This routine returns + <errorname>Successful</errorname> if everything went OK. It + returns <errorname>FPEResetFailed</errorname> if (for some + reason) the reset failed, and the caller should remove the + old FPE and simply create a new one in its place. This is + used by the disk-based fonts routine as resetting the + internal directory structures would be more complicated than + simply having destroying the old and creating a new. + </para> + </sect2> + + <sect2 id='free_fpe'> + <title> + (*free_fpe) + </title> + + <para> + When the server is finished with an FPE, this function is + called to dispose of any internal state. It should return + <errorname>Successful</errorname>, unless something terrible + happens. + </para> + </sect2> + + <sect2 id='open_font'> + <title> + (*open_font) + </title> + + <para> + This routine requests that a font be opened. The <parameter + class='function'>client</parameter> argument is used by the + font library only in connection with suspending/restarting + the request. The <parameter class='function'>flags</parameter> + argument specifies some behaviour for the library and can be + any of: + </para> + + <programlisting remap='.nf'> +/* OpenFont flags */ +#define FontLoadInfo 0x0001 +#define FontLoadProps 0x0002 +#define FontLoadMetrics 0x0004 +#define FontLoadBitmaps 0x0008 +#define FontLoadAll 0x000f +#define FontOpenSync 0x0010 + </programlisting> <!-- .fi --> + + <para> + The various fields specify which portions of the font should + be loaded at this time. When <constant>FontOpenSync</constant> + is specified, this routine will not return until all of the + requested portions are loaded. Otherwise, this routine may + return <errorname>Suspended</errorname>. When the presented + font name is actually an alias for some other font name, + <errorname>FontNameAlias</errorname> is returned, and the + actual font name is stored in the location pointed to by the + <parameter class='function'>alias</parameter> argument as a + null-terminated string. + </para> + </sect2> + + <sect2 id='close_font'> + <title> + (*close_font) + </title> + + <para> + When the server is finished with a font, this routine + disposes of any internal state and frees the font data + structure. + </para> + </sect2> + + <sect2 id='list_fonts'> + <title> + (*list_fonts) + </title> + + <para> + The <parameter class='function'>paths</parameter> argument is + a data structure which will be filled with all of the font names + from this directory which match the specified + <parameter class='function'>pattern</parameter>. At + most <parameter class='function'>maxnames</parameter> will be added. + This routine may return <errorname>Suspended</errorname>. + </para> + </sect2> + + <sect2 id='start_list_fonts_with_info'> + <title> + (*start_list_fonts_with_info) + </title> + + <para> + This routine sets any internal state for a verbose listing of + all fonts matching the specified pattern. This routine may + return <errorname>Suspended</errorname>. + </para> + </sect2> + + <sect2 id='list_next_font_with_info'> + <title> + (*list_next_font_with_info) + </title> + + <para> + To avoid storing huge amounts of data, the interface for + ListFontsWithInfo allows the server to get one reply at a time + and forward that to the client. When the font name returned + is actually an alias for some other font, + <errorname>FontNameAlias</errorname> will be returned. The + actual font name is return instead, and the font alias which + matched the pattern is returned in the location pointed to by + data as a null-terminated string. The caller can then get the + information by recursively listing that font name with a + maxnames of 1. When <errorname>Successful</errorname> is + returned, the matching font name is returned, and a + FontInfoPtr is stored in the location pointed to by + <parameter class='function'>data</parameter>. + <parameter class='function'>Data</parameter> must be initialized + with a pointer to a FontInfoRec allocated by the caller. When the + pointer pointed to by <parameter class='function'>data</parameter> + is not left pointing at that storage, the caller mustn't free the + associated property data. This routine may return + <errorname>Suspended</errorname>. + </para> + </sect2> + + <sect2 id='wakeup_fpe'> + <title> + (*wakeup_fpe) + </title> + + <para> + Whenever an FPE function has returned + <errorname>Suspended</errorname>, this routine is called + whenever the application wakes up from waiting for input + (from <citerefentry><refentrytitle>select</refentrytitle> + <manvolnum>2</manvolnum></citerefentry>). This + <parameter class='function'>mask</parameter> argument should be + the value returned from <function>select(2)</function>. + </para> + </sect2> + + <sect2 id='client_died'> + <title> + (*client_died) + </title> + + <para> + When an FPE function has returned <errorname>Suspended</errorname> + and the associated client is being destroyed, this function + allows the font library to dispose of any state associated + with that client. + </para> + </sect2> + </sect1> + + <sect1 id='fonts'> + <title> + Fonts + </title> + + <para> + The data structure which actually contains the font information has + changed significantly since previous releases; it now attempts to + hide the actual storage format for the data from the application, + providing accessor functions to get at the data. This allows a + range of internal details for different font sources. The structure + is split into two pieces, so that ListFontsWithInfo can share + information from the font when it has been loaded. The + <structname>FontInfo</structname> structure, then, contains only + information germane to LFWI. + </para> + + <programlisting remap='.nf'> +typedef struct _FontInfo { + unsigned short firstCol; /* range of glyphs for this font */ + unsigned short lastCol; + unsigned short firstRow; + unsigned short lastRow; + unsigned short defaultCh; /* default character index */ + unsigned int noOverlap:1; /* no combination of glyphs overlap */ + unsigned int terminalFont:1; /* Character cell font */ + unsigned int constantMetrics:1; /* all metrics are the same */ + unsigned int constantWidth:1; /* all character widths are the same*/ + unsigned int inkInside:1; /* all ink inside character cell */ + unsigned int inkMetrics:1; /* font has ink metrics */ + unsigned int allExist:1; /* no missing chars in range */ + unsigned int drawDirection:2; /* left-to-right/right-to-left*/ + unsigned int cachable:1; /* font needn't be opened each time*/ + unsigned int anamorphic:1; /* font is strangely scaled */ + short maxOverlap; /* maximum overlap amount */ + short pad; /* unused */ + xCharInfo maxbounds; /* glyph metrics maximums */ + xCharInfo minbounds; /* glyph metrics minimums */ + xCharInfo ink_maxbounds; /* ink metrics maximums */ + xCharInfo ink_minbounds; /* ink metrics minimums */ + short fontAscent; /* font ascent amount */ + short fontDescent; /* font descent amount */ + int nprops; /* number of font properties */ + FontPropPtr props; /* font properties */ + char *isStringProp; /* boolean array */ +} FontInfoRec, *FontInfoPtr; + </programlisting> <!-- .fi --> + + <para> + The font structure, then, contains a font info record, the format of + the bits in each bitmap and the functions which access the font + records (which are stored in an opaque format hung off of + <structfield>fontPrivate</structfield>). + </para> + + <programlisting remap='.nf'> +typedef struct _Font { + int refcnt; + FontInfoRec info; + char bit; /* bit order: LSBFirst/MSBFirst */ + char byte; /* byte order: LSBFirst/MSBFirst */ + char glyph; /* glyph pad: 1, 2, 4 or 8 */ + char scan; /* glyph scan unit: 1, 2 or 4 */ + fsBitmapFormat format; /* FS-style format (packed) */ + int (*get_glyphs) ( /* font, count, chars, encoding, count, glyphs */ ); + int (*get_metrics) ( /* font, count, chars, encoding, count, glyphs */ ); + int (*get_bitmaps) ( /* client, font, flags, format, + flags, nranges, ranges, data_sizep, + num_glyphsp, offsetsp, glyph_datap, + free_datap */ ); + int (*get_extents) ( /* client, font, flags, nranges, + ranges, nextentsp, extentsp */); + void (*unload_font) ( /* font */ ); + FontPathElementPtr fpe; /* FPE associated with this font */ + pointer svrPrivate; /* X/FS private data */ + pointer fontPrivate; /* private to font */ + pointer fpePrivate; /* private to FPE */ + int maxPrivate; /* devPrivates (see below) */ + pointer *devPrivates; /* ... */ +} FontRec, *FontPtr; + </programlisting> <!-- .fi --> + + <para> + Yes, there are several different private pointers in the + <structfield>Font</structfield> structure; they were added + haphazardly until the devPrivate pointers were added. Future + releases may remove some (or all) of the specific pointers, + leaving only the <structfield>devPrivates</structfield>mechanism. + </para> + + <para> + There are two similar interfaces implemented - + <structfield>get_glyphs</structfield>/<structfield>get_metrics</structfield> + and + <structfield>get_bitmaps</structfield>/<structfield>get_extents</structfield>. + Too little time caused the font-server specific interfaces to + be placed in the font library (and portions duplicated in each + renderer) instead of having them integrated into the font server + itself. This may change. The X server uses only + <structfield>get_glyphs</structfield>/<structfield>get_metrics</structfield>, + and those will not change dramatically. Each of the routines + is described below. + </para> + + <sect2 id='get_glyphs'> + <title> + (*get_glyphs) + </title> + + <para> + This routine returns <structname>CharInfoPtrs</structname> + for each of the requested characters in the font. If the + character does not exist in the font, the default character + will be returned, unless no default character exists in + which case that character is skipped. Thus, the number of + glyphs returned will not always be the same as the number of + characters passed in. + </para> + </sect2> + + <sect2 id='get_metrics'> + <title> + (*get_metrics) + </title> + + <para> + This is similar to <structfield>(*get_glyphs)</structfield> + except that pointers to <structname>xCharInfo</structname> + structures are returned, and, if the font has ink metrics, + those are returned instead of the bitmap metrics. + </para> + </sect2> + + <sect2 id='getbitmaps'> + <title> + (*get_bitmaps) + </title> + + <para> + This packs the glyph image data in the requested + <parameter class='function'>format</parameter> and returns it. The + <parameter class='function'>ranges</parameter>/<parameter class='function'>nranges</parameter> + argument specify the set of glyphs from the font to pack together. + </para> + </sect2> + + <sect2 id='get_extents'> + <title> + (*get_extents) + </title> + + <para> + This returns the metrics for the specified font from the + specified <parameter class='function'>ranges</parameter>. + </para> + + </sect2> + + <sect2 id='unload_font'> + <title> + (*unload_font) + </title> + + <para> + This is called from the FPE routine + <function>(*close_font)</function>, and so should not ever be + called from the application. + </para> + </sect2> + + <sect2 id='maxprivate'> + <title> + maxPrivate + </title> + + <para> + When initializing a new font structure, + <structfield>maxPrivate</structfield> should be set to -1 so + that the <function>FontSetPrivate()</function> macro works + properly with an index of 0. Initializing + <structfield>maxPrivate</structfield> to 0 can cause + problems if the server tries to set something at index 0. + </para> + </sect2> + </sect1> + </article> diff --git a/doc/fontlib.xsl b/doc/fontlib.xsl new file mode 100644 index 0000000..644f147 --- /dev/null +++ b/doc/fontlib.xsl @@ -0,0 +1,38 @@ +<?xml version="1.0" encoding="utf-8"?> +<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" + version="1.0"> + <!-- + Copyright 2009 Sun Microsystems, Inc. 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