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Diffstat (limited to 'doc')
| -rw-r--r-- | doc/xorg-docs/Makefile.bsd-wrapper | 21 | ||||
| -rw-r--r-- | doc/xorg-docs/general/fonts/defs.ent | 2 | ||||
| -rw-r--r-- | doc/xorg-docs/general/fonts/fonts.7 | 1617 |
3 files changed, 1639 insertions, 1 deletions
diff --git a/doc/xorg-docs/Makefile.bsd-wrapper b/doc/xorg-docs/Makefile.bsd-wrapper index c31becb15..3bf1dd5d8 100644 --- a/doc/xorg-docs/Makefile.bsd-wrapper +++ b/doc/xorg-docs/Makefile.bsd-wrapper @@ -1,5 +1,24 @@ -# $OpenBSD: Makefile.bsd-wrapper,v 1.2 2012/03/10 18:41:37 matthieu Exp $ +# $OpenBSD: Makefile.bsd-wrapper,v 1.3 2019/04/30 21:37:43 schwarze Exp $ CONFIGURE_ARGS += --without-fop --without-xmlto +MDOCS = general/fonts/fonts + +beforeinstall: +.for n in ${MDOCS} + ${INSTALL} ${INSTALL_COPY} -o ${MANOWN} -g ${MANGRP} -m ${MANMODE} \ + ${.CURDIR}/${n}.7 ${MANDIR}7 +.endfor + +# maintainer target, not used duing build or install +mdoc: +.for n in ${MDOCS} + { \ + echo ".\\\" automatically generated with"; \ + echo ".\\\" docbook2mdoc ${n:T}.xml > ${n:T}.7"; \ + docbook2mdoc ${.CURDIR}/${n}.xml; \ + } > ${.CURDIR}/${n}.7 + sed -i 's/^\.Dt ${n:T:U} 1$$/.Dt ${n:T:U} 7/' ${.CURDIR}/${n}.7 +.endfor + .include <bsd.xorg.mk> diff --git a/doc/xorg-docs/general/fonts/defs.ent b/doc/xorg-docs/general/fonts/defs.ent new file mode 100644 index 000000000..b9d1faa39 --- /dev/null +++ b/doc/xorg-docs/general/fonts/defs.ent @@ -0,0 +1,2 @@ +<!ENTITY relvers "6"> +<!ENTITY fullrelvers "6"> diff --git a/doc/xorg-docs/general/fonts/fonts.7 b/doc/xorg-docs/general/fonts/fonts.7 new file mode 100644 index 000000000..7075a2f5a --- /dev/null +++ b/doc/xorg-docs/general/fonts/fonts.7 @@ -0,0 +1,1617 @@ +.\" automatically generated with +.\" docbook2mdoc fonts.xml > fonts.7 +.Dd 16 March 2012 +.Dt FONTS 7 +.Os +.Sh NAME +.Nm fonts +.Nd Fonts in X11R6 +.Sh INTRODUCTION +This document describes the support for fonts in X11R6. +.Sx Installing_fonts +is aimed at the +casual user wishing to install fonts in X11R6 the rest of the +document describes the font support in more detail. +.Pp +We assume some familiarity with digital fonts. If anything is not +clear to you, please consult +.Sx Appendix_background_and_terminology +at the +end of this document for background information. +.Ss Two font systems +X11 includes two font systems: the original core X11 fonts +system, which is present in all implementations of X11, and the Xft +fonts system, which may not yet be distributed with implementations of +X11 that are not based on either XFree86 or X11R6.8 or later. +.Pp +The core X11 fonts system is directly derived from the fonts system +included with X11R1 in 1987, which could only use monochrome bitmap +fonts. Over the years, it has been more or less happily coerced into +dealing with scalable fonts and rotated glyphs. +.Pp +Xft was designed from the start to provide good support for scalable +fonts, and to do so efficiently. Unlike the core fonts system, it +supports features such as anti-aliasing and sub-pixel rasterisation. +Perhaps more importantly, it gives applications full control over the +way glyphs are rendered, making fine typesetting and WYSIWIG display +possible. Finally, it allows applications to use fonts that are not +installed system-wide for displaying documents with embedded fonts. +.Pp +Xft is not compatible with the core fonts system: usage of Xft +requires fairly extensive changes to toolkits (user-interface +libraries). While X.Org will continue to maintain the core fonts +system, toolkit authors are encouraged to switch to Xft as soon as +possible. +.Sh INSTALLING FONTS +This section explains how to configure both Xft and the core fonts +system to access newly-installed fonts. +.Ss Configuring Xft +Xft has no configuration mechanism itself, it relies upon the +.Lk http://www.fontconfig.org/ fontconfig +library to configure and customise fonts. That library is +not specific to the X Window system, and does not rely on any +particular font output mechanism. +.Pp +.Sy Installing fonts in Xft +.Pp +Fontconfig looks for fonts in a set of well-known directories that +include all of X11R6's standard font directories +.Pf ( Pa /usr/share/fonts/X11/* ) +by default) as well as a +directory called +.Pa .fonts/ +in the user's home directory. +Installing a font for use by Xft applications is as simple +as copying a font file into one of these directories. +.Bd -literal +$ cp lucbr.ttf ~/.fonts/ +.Ed +.Pp +Fontconfig will notice the new font at the next opportunity and rebuild its +list of fonts. If you want to trigger this update from the command +line, you may run the command +.Dq Nm fc-cache . +.Bd -literal +$ fc-cache +.Ed +.Pp +In order to globally update the system-wide Fontconfig information on +Unix systems, you will typically need to run this command as root: +.Bd -literal +$ su -c fc-cache +.Ed +.Pp +.Sy Fine-tuning Xft +.Pp +Fontconfig's behaviour is controlled by a set of configuration +files: a standard configuration file, +.Pa /etc/fonts/fonts.conf , +a host-specific configuration file, +.Pa /etc/fonts/local.conf , +and a user-specific file called +.Pa .fonts.conf +in the user's +home directory (this can be overridden with the +.Dq Ev FONTCONFIG_FILE +environment variable). +.Pp +Every Fontconfig configuration file must start with the following +boilerplate: +.Bd -literal +<?xml version="1.0"?> +<!DOCTYPE fontconfig SYSTEM "fonts.dtd"> +<fontconfig> +.Ed +.Pp +In addition, every Fontconfig configuration file must end with the +following line: +.Bd -literal +</fontconfig> +.Ed +.Pp +The default Fontconfig configuration file includes the directory +.Pa \[u02DC]/.fonts/ +in the list of directories searched for font +files, and this is where user-specific font files should be installed. +In the unlikely case that a new font directory needs to be added, this +can be done with the following syntax: +.Bd -literal +<dir>/usr/local/share/fonts/</dir> +.Ed +.Pp +Another useful option is the ability to disable anti-aliasing (font +smoothing) for selected fonts. This can be done with the following +syntax: +.Bd -literal +<match target="font"> +<test qual="any" name="family"> +<string>Lucida Console</string> +</test> +<edit name="antialias" mode="assign"> +<bool>false</bool> +</edit> +</match> +.Ed +.Pp +Anti-aliasing can be disabled for all fonts by the following incantation: +.Bd -literal +<match target="font"> +<edit name="antialias" mode="assign"> +<bool>false</bool> +</edit> +</match> +.Ed +.Pp +Xft supports sub-pixel rasterisation on LCD displays. X11R6 should +automatically enable this feature on laptops and when using an LCD +monitor connected with a DVI cable; you can check whether this was +done by typing +.Bd -literal +$ xdpyinfo -ext RENDER | grep sub-pixel +.Ed +.Pp +If this doesn't print anything, you will need to configure Render for +your particular LCD hardware manually; this is done with the following +syntax: +.Bd -literal +<match target="font"> +<edit name="rgba" mode="assign"> +<const>rgb</const> +</edit> +</match> +.Ed +.Pp +The string +.Dq Li rgb +within the +.Dq Li <const> . . . Ns Dq Ns Li </const> +specifies the order of pixel components on your display, and should be +changed to match your hardware; it can be one of +.Dq Li rgb +(normal +LCD screen), +.Dq Li bgr +(backwards LCD screen), +.Dq Li vrgb +(LCD +screen rotated clockwise) or +.Dq Li vbgr +(LCD screen rotated +counterclockwise). +.Pp +.Sy Configuring applications +.Pp +A growing number of applications use Xft in preference to the core +fonts system. Some applications, however, need to be explicitly +configured to use Xft. +.Pp +A case in point is XTerm, which can be set to use Xft by using the +.Dq Li -fa +command line option or by setting the +.Dq Li XTerm*faceName +resource: +.Bd -literal +XTerm*faceName: Courier +.Ed +.Pp +or +.Bd -literal +$ xterm -fa "Courier" +.Ed +.Pp +For KDE applications, you should select +.Dq Anti-alias fonts +in the +.Dq Fonts +panel of KDE's +.Dq Control Center . +Note that this option is +misnamed: it switches KDE to using Xft but doesn't enable +anti-aliasing in case it was disabled by your Xft configuration file. +.Pp +Gnome applications and Mozilla Firefox will use Xft by default. +.Ss Configuring the core X11 fonts system +Installing fonts in the core system is a two step process. First, +you need to create a +.Em font directory +that contains all the +relevant font files as well as some index files. You then need to +inform the X server of the existence of this new directory by +including it in the +.Em font path . +.Pp +.Sy Installing bitmap fonts +.Pp +The X11R6 server can use bitmap fonts in both the cross-platform +BDF format and the somewhat more efficient binary PCF format. +(X11R6 also supports the obsolete SNF format.) +.Pp +Bitmap fonts are normally distributed in the BDF format. Before +installing such fonts, it is desirable (but not absolutely necessary) +to convert the font files to the PCF format. This is done by using the +command +.Dq Nm bdftopcf , +.Em e.g. +.Bd -literal +$ bdftopcf courier12.bdf +.Ed +.Pp +You may then want to compress the resulting PCF font files: +.Bd -literal +$ gzip courier12.pcf +.Ed +.Pp +After the fonts have been converted, you should copy all the font +files that you wish to make available into a arbitrary directory, say +.Pa /usr/local/share/fonts/bitmap/ . +You should then create the +index file +.Pa fonts.dir +by running the command +.Dq Nm mkfontdir +(please see the +.Lk mkfontdir.1.html mkfontdir(1) +manual page for more information): +.Bd -literal +$ mkdir /usr/local/share/fonts/bitmap/ +$ cp *.pcf.gz /usr/local/share/fonts/bitmap/ +$ mkfontdir /usr/local/share/fonts/bitmap/ +.Ed +.Pp +All that remains is to tell the X server about the existence of the +new font directory; see +.Sx Setting_the_servers_font_path +below. +.Pp +.Sy Installing scalable fonts +.Pp +The X11R6 server supports scalable fonts in multiple +formats, including Type\ 1, TrueType, and OpenType/CFF. +(Earlier versions of X11 also included support for the Speedo and +CID scalable font formats, but that is not included in current releases.) +.Pp +Installing scalable fonts is very similar to installing bitmap fonts: +you create a directory with the font files, and run +.Dq Nm mkfontdir +to create an index file called +.Pa fonts.dir . +.Pp +There is, however, a big difference: +.Dq Nm mkfontdir +cannot +automatically recognise scalable font files. For that reason, you +must first index all the font files in a file called +.Pa fonts.scale . +While this can be done by hand, it is best done +by using the +.Dq Nm mkfontscale +utility. +.Bd -literal +$ mkfontscale /usr/local/share/fonts/Type1/ +$ mkfontdir /usr/local/share/fonts/Type1/ +.Ed +.Pp +Under some circumstances, it may be necessary to modify the +.Pa fonts.scale +file generated by +.Nm mkfontscale ; +for more +information, please see the +.Lk mkfontdir.1.html mkfontdir(1) +and +.Lk mkfontscale.1.html mkfontscale(1) +manual pages and +.Sx Core_fonts_and_internationalisation +later in this document. +.Pp +.Sy CID-keyed fonts +.Pp +The CID-keyed font format was designed by Adobe Systems for fonts +with large character sets. The CID-keyed format is obsolete, as it +has been superseded by other formats such as OpenType/CFF and +support for CID-keyed fonts has been removed from X11. +.Pp +.Sy Setting the server's font path +.Pp +The list of directories where the server looks for fonts is known +as the +.Em font path . +Informing the server of the existence of a new +font directory consists of putting it on the font path. +.Pp +The font path is an ordered list; if a client's request matches +multiple fonts, the first one in the font path is the one that gets +used. When matching fonts, the server makes two passes over the font +path: during the first pass, it searches for an exact match; during +the second, it searches for fonts suitable for scaling. +.Pp +For best results, scalable fonts should appear in the font path before +the bitmap fonts; this way, the server will prefer bitmap fonts to +scalable fonts when an exact match is possible, but will avoid scaling +bitmap fonts when a scalable font can be used. (The +.Dq Li :unscaled +hack, while still supported, should no longer be necessary in X11R6.) +.Pp +You may check the font path of the running server by typing the command +.Bd -literal +$ xset q +.Ed +.Pp +.Sy Font path catalogue directories +.Pp +You can specify a special kind of font path directory in the form +.Pa catalogue:<dir> . +The directory specified after the +.Pa catalogue: +prefix will be scanned for symlinks and each symlink destination will be +added as a local font path entry. +.Pp +The symlink can be suffixed by attributes such as +.Pf ' Ql unscaled Ns ', +which will be passed through +to the underlying font path entry. The only exception is the newly +introduced +.Pf ' Ql pri Ns ' +attribute, which will be +used for ordering the font paths specified by the symlinks. +.Pp +An example configuration: +.Bd -literal + 75dpi:unscaled:pri=20 -> /usr/share/X11/fonts/75dpi + ghostscript:pri=60 -> /usr/share/fonts/default/ghostscript + misc:unscaled:pri=10 -> /usr/share/X11/fonts/misc + type1:pri=40 -> /usr/share/X11/fonts/Type1 + type1:pri=50 -> /usr/share/fonts/default/Type1 +.Ed +.Pp +This will add +.Pa /usr/share/X11/fonts/misc +as the +first font path entry with the attribute +.Ql unscaled . +This is functionally equivalent to +setting the following font path: +.Bd -literal + /usr/share/X11/fonts/misc:unscaled, + /usr/share/X11/fonts/75dpi:unscaled, + /usr/share/X11/fonts/Type1, + /usr/share/fonts/default/Type1, + /usr/share/fonts/default/ghostscript +.Ed +.Pp +.Sy Temporary modification of the font path +.Pp +The +.Dq Nm xset +utility may be used to modify the font path for the +current session. The font path is set with the command +.Nm xset fp ; +a new element is added to the front with +.Nm xset +fp , +and added to +the end with +.Nm xset fp+ . +For example, +.Bd -literal +$ xset +fp /usr/local/fonts/Type1 +$ xset fp+ /usr/local/fonts/bitmap +.Ed +.Pp +Conversely, an element may be removed from the front of the font path +with +.Dq Nm xset -fp , +and removed from the end with +.Dq Nm xset fp- . +You may reset the font path to its default value with +.Dq Nm xset fp default . +.Pp +For more information, please consult the +.Lk xset.1.html xset(1) +manual page. +.Pp +.Sy Permanent modification of the font path +.Pp +The default font path (the one used just after server startup or +after +.Dq Nm xset fp default ) +may be specified in the +X server's +.Pa xorg.conf +file. It is computed by appending all the +directories mentioned in the +.Dq Li FontPath +entries of the +.Dq Li Files +section in the order in which they appear. If no font path is specified in a config file, the server uses a default +value specified when it was built. +.Bd -literal +FontPath "/usr/local/fonts/Type1" +\&... +FontPath "/usr/local/fonts/bitmap" +.Ed +.Pp +For more information, please consult the +.Lk xorg.conf.5.html xorg.conf(5) +manual page. +.Pp +.Sy Troubleshooting +.Pp +If you seem to be unable to use some of the fonts you have +installed, the first thing to check is that the +.Pa fonts.dir +files +are correct and that they are readable by the server (the X server +usually runs as root, beware of NFS-mounted font directories). If +this doesn't help, it is quite possible that you are trying to use a +font in a format that is not supported by your server. +.Pp +X11R6 supports the BDF, PCF, SNF, Type 1, TrueType, and OpenType +font formats. However, not all X11R6 servers +come with all the font backends configured in. +.Pp +On most platforms, the X11R6 servers no longer uses font +backends from modules that are loaded at runtime. The built in +font support corresponds to the functionality formerly provided by +these modules: +.Bl -bullet +.It +.Ql \(dqbitmap\(dq : +bitmap fonts +.Pf ( Pa *.bdf , +.Pa *.pcf +and +.Pa *.snf ) ; +.It +.Ql \(dqfreetype\(dq : +TrueType fonts +.Pf ( Pa *.ttf +and +.Pa *.ttc ) , +OpenType fonts +.Pf ( Pa *.otf +and +.Pa *.otc ) +and +Type\ 1 fonts +.Pf ( Pa *.pfa +and +.Pa *.pfb ) . +.El +.Sh FONTS INCLUDED WITH X11R6 +.Ss Standard bitmap fonts +The Sample Implementation of X11 (SI) comes with a large number of +bitmap fonts, including the +.Dq Li fixed +family, and bitmap versions +of Courier, Times, Helvetica and some members of the Lucida family. +.Pp +In X11R6, a number of these fonts are provided in Unicode-encoded +font files now. At build time, these fonts are split into font +files encoded according to legacy encodings, a process which allows +us to provide the standard fonts in a number of regional encodings +with no duplication of work. +.Pp +For example, the font file +.Bd -literal +/usr/share/fonts/X11/misc/6x13.bdf +.Ed +.Pp +with XLFD +.Bd -literal +-misc-fixed-medium-r-semicondensed--13-120-75-75-c-60-iso10646-1 +.Ed +.Pp +is a Unicode-encoded version of the standard +.Dq Li fixed +font with +added support for the Latin, Greek, Cyrillic, Georgian, Armenian, IPA +and other scripts plus numerous technical symbols. It contains over +2800 glyphs, covering all characters of ISO\ 8859 parts 1-5, +7-10, 13-15, as well as all European IBM and Microsoft code pages, +KOI8, WGL4, and the repertoires of many other character sets. +.Pp +This font is used at build time for generating the font files +.Bd -literal +6x13-ISO8859-1.bdf +6x13-ISO8859-2.bdf +\&... +6x13-ISO8859-15.bdf +6x13-KOI8-R.bdf +.Ed +.Pp +with respective XLFDs +.Bd -literal +-misc-fixed-medium-r-normal--13-120-75-75-c-60-iso8859-1 +\&... +-misc-fixed-medium-r-normal--13-120-75-75-c-60-iso8859-15 +-misc-fixed-medium-r-normal--13-120-75-75-c-60-koi8-r +.Ed +.Pp +The standard short name +.Dq Li fixed +is normally an alias for +.Bd -literal +-misc-fixed-medium-r-normal--13-120-75-75-c-60-iso8859-1 +.Ed +.Ss The ClearlyU Unicode font family +The ClearlyU family of fonts provides a set of 12\ pt, +100\ dpi proportional fonts with many of the glyphs needed for +Unicode text. Together, the fonts contain approximately 7500 glyphs. +.Pp +The main ClearlyU font has the XLFD +.Bd -literal +-mutt-clearlyu-medium-r-normal--17-120-100-100-p-101-iso10646-1 +.Ed +.Pp +and resides in the font file +.Bd -literal +/usr/share/fonts/X11/misc/cu12.pcf.gz +.Ed +.Pp +Additional ClearlyU fonts include +.Bd -literal +-mutt-clearlyu alternate glyphs-medium-r-normal--17-120-100-100-p-91-iso10646-1 +-mutt-clearlyu pua-medium-r-normal--17-120-100-100-p-111-iso10646-1 +-mutt-clearlyu arabic extra-medium-r-normal--17-120-100-100-p-103-fontspecific-0 +-mutt-clearlyu ligature-medium-r-normal--17-120-100-100-p-141-fontspecific-0 +.Ed +.Pp +The +.Em Alternate Glyphs +font contains additional glyph shapes that +are needed for certain languages. A second alternate glyph font will +be provided later for cases where a character has more than one +commonly used alternate shape +.Pf ( Em e.g. +the Urdu heh). +.Pp +The +.Em PUA +font contains extra glyphs that are useful for certain +rendering purposes. +.Pp +The +.Em Arabic Extra +font contains the glyphs necessary for +characters that don't have all of their possible shapes encoded in +ISO\ 10646. The glyphs are roughly ordered according to the order +of the characters in the ISO\ 10646 standard. +.Pp +The +.Em Ligature +font contains ligatures for various scripts that +may be useful for improved presentation of text. +.Ss Standard scalable fonts +X11R6 includes all the scalable fonts distributed with X11R6. +.Pp +.Sy Standard Type\e1 fonts +.Pp +The IBM Courier set of fonts cover ISO\ 8859-1 and +ISO\ 8859-2 as well as Adobe Standard Encoding. These fonts have +XLFD +.Bd -literal +-adobe-courier-medium-*-*--0-0-0-0-m-0-*-* +.Ed +.Pp +and reside in the font files +.Bd -literal +/usr/share/fonts/X11/Type1/cour*.pfa +.Ed +.Pp +The Adobe Utopia set of fonts only cover ISO\ 8859-1 as well as +Adobe Standard Encoding. These fonts have XLFD +.Bd -literal +-adobe-utopia-*-*-normal--0-0-0-0-p-0-iso8859-1 +.Ed +.Pp +and reside in the font files +.Bd -literal +/usr/share/fonts/X11/Type1/UT*.pfa +.Ed +.Pp +Finally, X11R6 also comes with Type\ 1 versions of Bitstream +Courier and Charter. These fonts have XLFD +.Bd -literal +-bitstream-courier-*-*-normal--0-0-0-0-m-0-iso8859-1 +-bitstream-charter-*-*-normal--0-0-0-0-p-0-iso8859-1 +.Ed +.Pp +and reside in the font files +.Bd -literal +/usr/share/fonts/X11/Type1/c*bt_.pfb +.Ed +.Ss The Bigelow & Holmes Luxi family +X11R6 includes the +.Em Luxi +family of scalable fonts, in both +TrueType and Type\ 1 format. This family consists of the fonts +.Em Luxi Serif , +with XLFD +.Bd -literal +-b&h-luxi serif-medium-*-normal--*-*-*-*-p-*-*-* +.Ed +.Pp +.Em Luxi Sans , +with XLFD +.Bd -literal +-b&h-luxi sans-medium-*-normal--*-*-*-*-p-*-*-* +.Ed +.Pp +and +.Em Luxi Mono , +with XLFD +.Bd -literal +-b&h-luxi mono-medium-*-normal--*-*-*-*-m-*-*-* +.Ed +.Pp +Each of these fonts comes Roman, oblique, bold and bold oblique variants +The TrueType version have glyphs covering the basic ASCII Unicode +range, the Latin\ 1 range, as well as the +.Em Extended Latin +range and some additional punctuation characters. In particular, +these fonts include all the glyphs needed for ISO\ 8859 parts 1, +2, 3, 4, 9, 13 and 15, as well as all the glyphs in the Adobe Standard +encoding and the Windows 3.1 character set. +.Pp +The glyph coverage of the Type\ 1 versions is somewhat reduced, +and only covers ISO\ 8859 parts 1, 2 and 15 as well as the Adobe +Standard encoding. +.Pp +The Luxi fonts are original designs by Kris Holmes and Charles +Bigelow. Luxi fonts include seriffed, sans serif, and monospaced +styles, in roman and oblique, and normal and bold weights. The fonts +share stem weight, x-height, capital height, ascent and descent, for +graphical harmony. +.Pp +The character width metrics of Luxi roman and bold fonts match those +of core fonts bundled with popular operating and window systems. +.Pp +The license terms for the Luxi fonts are included in the file +.Pa COPYRIGHT.BH , +as well as in the +.Lk License "License document" +.Pq Bigelow_Holmes_Inc_and_URW_GmbH_Luxi_font_license . +.Pp +Charles Bigelow and Kris Holmes from Bigelow and Holmes Inc. +developed the Luxi typeface designs in Ikarus digital format. +.Pp +URW++ Design and Development GmbH converted the Ikarus format fonts +to TrueType and Type1 font programs and implemented the grid-fitting +"hints" and kerning tables in the Luxi fonts. +.Pp +For more information, please contact +.Aq Mt design@bigelowandholmes.com +or +.Aq Mt info@urwpp.de , +or consult +.Lk http://www.urwpp.de "the URW++ web site" . +.Pp +An earlier version of the Luxi fonts was made available under the +name +.Em Lucidux . +This name should no longer be used due to +trademark uncertainties, and all traces of the +.Em Lucidux +name have been removed from X11R6. +.Sh MORE ABOUT CORE FONTS +This section describes XFree86-created enhancements to the core +X11 fonts system that were adopted by X.Org. +.Ss Core fonts and internationalisation +The scalable font backends (Type\ 1 and TrueType) can +automatically re-encode fonts to the encoding specified in the +XLFD in +.Pa fonts.dir . +For example, a +.Pa fonts.dir +file can +contain entries for the Type\ 1 Courier font such as +.Bd -literal +cour.pfa -adobe-courier-medium-r-normal--0-0-0-0-m-0-iso8859-1 +cour.pfa -adobe-courier-medium-r-normal--0-0-0-0-m-0-iso8859-2 +.Ed +.Pp +which will lead to the font being recoded to ISO\ 8859-1 and +ISO\ 8859-2 respectively. +.Pp +.Sy The fontenc layer +.Pp +Two of the scalable backends (Type\ 1 and the +.Em FreeType +TrueType backend) use a common +.Em fontenc +layer for +font re-encoding. This allows these backends to share their encoding +data, and allows simple configuration of new locales independently of +font type. +.Pp +.Em Please note: +the X-TrueType (X-TT) backend is not included +in X11R6. That functionality has been merged into the FreeType +backend. +.Pp +In the +.Em fontenc +layer, an encoding is defined by a name (such as +.Ql iso8859-1 ) , +possibly a number of aliases (alternate names), and +an ordered collection of mappings. A mapping defines the way the +encoding can be mapped into one of the +.Em target encodings +known to +.Em fontenc ; +currently, these consist of Unicode, Adobe glyph names, +and arbitrary TrueType +.Dq cmap Ns s. +.Pp +A number of encodings are hardwired into +.Em fontenc , +and are +therefore always available; the hardcoded encodings cannot easily be +redefined. These include: +.Bl -bullet +.It +.Ql iso10646-1 : +Unicode; +.It +.Ql iso8859-1 : +ISO\ Latin-1 (Western Europe); +.It +.Ql iso8859-2 : +ISO\ Latin-2 (Eastern Europe); +.It +.Ql iso8859-3 : +ISO\ Latin-3 (Southern Europe); +.It +.Ql iso8859-4 : +ISO\ Latin-4 (Northern Europe); +.It +.Ql iso8859-5 : +ISO\ Cyrillic; +.It +.Ql iso8859-6 : +ISO\ Arabic; +.It +.Ql iso8859-7 : +ISO\ Greek; +.It +.Ql iso8859-8 : +ISO\ Hebrew; +.It +.Ql iso8859-9 : +ISO\ Latin-5 (Turkish); +.It +.Ql iso8859-10 : +ISO\ Latin-6 (Nordic); +.It +.Ql iso8859-15 : +ISO\ Latin-9, or Latin-0 (Revised +Western-European); +.It +.Ql koi8-r : +KOI8 Russian; +.It +.Ql koi8-u : +KOI8 Ukrainian (see RFC 2319); +.It +.Ql koi8-ru : +KOI8 Russian/Ukrainian; +.It +.Ql koi8-uni : +KOI8 +.Dq Unified +(Russian, Ukrainian, and +Byelorussian); +.It +.Ql koi8-e : +KOI8 +.Dq European, +ISO-IR-111, or ECMA-Cyrillic; +.It +.Ql microsoft-symbol +and +.Ql apple-roman : +these are only +likely to be useful with TrueType symbol fonts. +.El +.Pp +Additional encodings can be added by defining +.Em encoding files . +When a font encoding is requested that the +.Em fontenc +layer doesn't +know about, the backend checks the directory in which the font file +resides (not necessarily the directory with +.Pa fonts.dir ! ) +for a +file named +.Pa encodings.dir . +If found, this file is scanned for +the requested encoding, and the relevant encoding definition file is +read in. The +.Dq Nm mkfontdir +utility, when invoked with the +.Dq Li -e +option followed by the name of a directory containing +encoding files, can be used to automatically build +.Pa encodings.dir +files. Please see the +.Lk mkfontdir.1.html mkfontdir(1) +manual page for more details. +.Pp +A number of encoding files for common encodings are included with +X11R6. Information on writing new encoding files can be found in +.Sx Format_of_encoding_directory_files +and +.Sx Format_of_encoding_files +later in this document. +.Pp +.Sy Backend-specific notes about fontenc +.Pp +.Sy The FreeType backend +.Pp +For TrueType and OpenType fonts, the FreeType backend scans the +mappings in order. Mappings with a target of PostScript are ignored; +mappings with a TrueType or Unicode target are checked against all the +cmaps in the file. The first applicable mapping is used. +.Pp +For Type\ 1 fonts, the FreeType backend first searches for a +mapping with a target of PostScript. If one is found, it is used. +Otherwise, the backend searches for a mapping with target Unicode, +which is then composed with a built-in table mapping codes to glyph +names. Note that this table only covers part of the Unicode code +points that have been assigned names by Adobe. +.Pp +Specifying an encoding value of +.Ql adobe-fontspecific +for a +Type\ 1 font disables the encoding mechanism. This is useful with +symbol and incorrectly encoded fonts (see +.Sx Hints_about_using_badly_encoded_fonts +below). +.Pp +If a suitable mapping is not found, the FreeType backend defaults to +ISO\ 8859-1. +.Pp +.Sy Format of encoding directory files +.Pp +In order to use a font in an encoding that the font backend does +not know about, you need to have an +.Pa encodings.dir +file either +in the same directory as the font file used or in a system-wide +location +.Pf ( Pa /usr/share/fonts/X11/encodings/ +by default). +.Pp +The +.Pa encodings.dir +file has a similar format to +.Pa fonts.dir . +Its first line specifies the number of encodings, +while every successive line has two columns, the name of the encoding, +and the name of the encoding file; this can be relative to the current +directory, or absolute. Every encoding name should agree with the +encoding name defined in the encoding file. For example, +.Bd -literal +3 +mulearabic-0 /usr/share/fonts/X11/encodings/mulearabic-0.enc +mulearabic-1 /usr/share/fonts/X11/encodings/mulearabic-1.enc +mulearabic-2 /usr/share/fonts/X11/encodings/mulearabic-2.enc +.Ed +.Pp +The name of an encoding +.Em must +be specified in the encoding file's +.Dq Li STARTENCODING +or +.Dq Li ALIAS +line. It is not enough to create +an +.Pa encodings.dir +entry. +.Pp +If your platform supports it (it probably does), encoding files may be +compressed or gzipped. +.Pp +The +.Pa encoding.dir +files are best maintained by the +.Dq Nm mkfontdir +utility. Please see the +.Lk mkfontdir.1.html mkfontdir(1) +manual page for more information. +.Pp +.Sy Format of encoding files +.Pp +The encoding files are +.Dq free form, +.Em i.e. +any string of +whitespace is equivalent to a single space. Keywords are parsed in a +non-case-sensitive manner, meaning that +.Dq Li size , +.Dq Li SIZE , +and +.Dq Li SiZE +all parse as the same keyword; on the other hand, case is +significant in glyph names. +.Pp +Numbers can be written in decimal, as in +.Dq Li 256 , +in hexadecimal, +as in +.Dq Li 0x100 , +or in octal, as in +.Dq Li 0400 . +.Pp +Comments are introduced by a hash sign +.Dq Li # . +A +.Dq Li # +may +appear at any point in a line, and all characters following the +.Dq Li # +are ignored, up to the end of the line. +.Pp +The encoding file starts with the definition of the name of the +encoding, and possibly its alternate names (aliases): +.Bd -literal +STARTENCODING mulearabic-0 +ALIAS arabic-0 +.Ed +.Pp +The name of the encoding and its aliases should be suitable for use in +an XLFD font name, and therefore contain exactly one dash +.Dq Li - . +.Pp +The encoding file may then optionally declare the size of the +encoding. For a linear encoding (such as ISO\ 8859-1), the SIZE +line specifies the maximum code plus one: +.Bd -literal +SIZE 0x2B +.Ed +.Pp +For a matrix encoding, it should specify two numbers. The first is +the number of the last row plus one, the other, the highest column +number plus one. In the case of +.Dq Li jisx0208.1990-0 +(JIS\ X\ 0208(1990), double-byte encoding, high bit clear), it +should be +.Bd -literal +SIZE 0x75 0x80 +.Ed +.Pp +In the case of a matrix encoding, a +.Dq Li FIRSTINDEX +line may be +included to specify the minimum glyph index in an encoding. The +keyword +.Dq Li FIRSTINDEX +is followed by two integers, the minimum row +number followed by the minimum column number: +.Bd -literal +FIRSTINDEX 0x20 0x20 +.Ed +.Pp +In the case of a linear encoding, a +.Dq Li FIRSTINDEX +line is not very +useful. If for some reason however you chose to include on, it should +be followed by a single integer. +.Pp +Note that in most font backends inclusion of a +.Dq Li FIRSTINDEX +line +has the side effect of disabling default glyph generation, and this +keyword should therefore be avoided unless absolutely necessary. +.Pp +Codes outside the region defined by the +.Dq Li SIZE +and +.Dq Li FIRSTINDEX +lines are understood to be undefined. Encodings +default to linear encoding with a size of 256 (0x100). This means +that you must declare the size of all 16 bit encodings. +.Pp +What follows is one or more mapping sections. A mapping section +starts with a +.Dq Li STARTMAPPING +line stating the target of the mapping. +The target may be one of: +.Bl -bullet +.It +Unicode (ISO\ 10646): +.Bd -literal +STARTMAPPING unicode +.Ed +.It +a given TrueType +.Dq cmap : +.Bd -literal +STARTMAPPING cmap 3 1 +.Ed +.It +PostScript glyph names: +.Bd -literal +STARTMAPPING postscript +.Ed +.El +.Pp +Every line in a mapping section maps one from the encoding being +defined to the target of the mapping. In mappings with a Unicode or +TrueType mapping, codes are mapped to codes: +.Bd -literal +0x21 0x0660 +0x22 0x0661 +\&... +.Ed +.Pp +As an abbreviation, it is possible to map a contiguous range of codes +in a single line. A line consisting of three integers +.Bd -literal +\[u003C]it/start/ \[u003C]it/end/ \[u003C]it/target/ +.Ed +.Pp +is an abbreviation for the range of lines +.Bd -literal +.Em start +.Em target +.Ed +.Bd -literal +.Em start Ns +1 +.Em target Ns +1 +.Ed +.Bd -literal +\&... +.Ed +.Bd -literal +.Em end +.Em target Ns + Ns Em end Ns - Ns Em start +.Ed +.Pp +For example, the line +.Bd -literal +0x2121 0x215F 0x8140 +.Ed +.Pp +is an abbreviation for +.Bd -literal +0x2121 0x8140 +0x2122 0x8141 +\&... +0x215F 0x817E +.Ed +.Pp +Codes not listed are assumed to map through the identity +.Pf ( Em i.e. +to +the same numerical value). In order to override this default mapping, +you may specify a range of codes to be undefined by using an +.Dq Li UNDEFINE +line: +.Bd -literal +UNDEFINE 0x00 0x2A +.Ed +.Pp +or, for a single code, +.Bd -literal +UNDEFINE 0x1234 +.Ed +.Pp +PostScript mappings are different. Every line in a PostScript mapping +maps a code to a glyph name +.Bd -literal +0x41 A +0x42 B +\&... +.Ed +.Pp +and codes not explicitly listed are undefined. +.Pp +A mapping section ends with an +.Ql ENDMAPPING +line +.Bd -literal +ENDMAPPING +.Ed +.Pp +After all the mappings have been defined, the file ends with an +.Ql ENDENCODING +line +.Bd -literal +ENDENCODING +.Ed +.Pp +In order to make future extensions to the format possible, lines +starting with an unknown keyword are silently ignored, as are mapping +sections with an unknown target. +.Pp +.Sy Using symbol fonts +.Pp +Type\ 1 symbol fonts should be installed using the +.Ql adobe-fontspecific +encoding. +.Pp +In an ideal world, all TrueType symbol fonts would be installed using +one of the +.Ql microsoft-symbol +and +.Ql apple-roman +encodings. A +number of symbol fonts, however, are not marked as such; such fonts +should be installed using +.Ql microsoft-cp1252 , +or, for older fonts, +.Ql microsoft-win3.1 . +.Pp +In order to guarantee consistent results (especially between +Type\ 1 and TrueType versions of the same font), it is possible to +define a special encoding for a given font. This has already been done +for the +.Ql ZapfDingbats +font; see the file +.Pa encodings/adobe-dingbats.enc . +.Pp +.Sy Hints about using badly encoded fonts +.Pp +A number of text fonts are incorrectly encoded. Incorrect encoding +is sometimes done by design, in order to make a font for an exotic +script appear like an ordinary Western text font on systems which are +not easily extended with new locale data. It is often the result of +the font designer's laziness or incompetence; for some reason, most +people seem to find it easier to invent idiosyncratic glyph names +rather than follow the Adobe glyph list. +.Pp +There are two ways of dealing with such fonts: using them with the +encoding they were designed for, and creating an +.Em ad hoc +encoding +file. +.Pp +.Sy Using fonts with the designer's encoding +.Pp +In the case of Type\ 1 fonts, the font designer can specify a +default encoding; this encoding is requested by using the +.Dq Li adobe-fontspecific +encoding in the XLFD name. Sometimes, the +font designer omitted to specify a reasonable default encoding, in +which case you should experiment with +.Dq Li adobe-standard , +.Dq Li iso8859-1 , +.Dq Li microsoft-cp1252 , +and +.Dq Li microsoft-win3.1 . +(The encoding +.Dq Li microsoft-symbol +doesn't +make sense for Type\ 1 fonts). +.Pp +TrueType fonts do not have a default encoding. However, most TrueType +fonts are designed with either Microsoft or Apple platforms in mind, +so one of +.Dq Li microsoft-symbol , +.Dq Li microsoft-cp1252 , +.Dq Li microsoft-win3.1 , +or +.Dq Li apple-roman +should yield reasonable +results. +.Pp +.Sy Specifying an ad hoc encoding file +.Pp +It is always possible to define an encoding file to put the glyphs +in a font in any desired order. Again, see the +.Pa encodings/adobe-dingbats.enc +file to see how this is done. +.Pp +.Sy Specifying font aliases +.Pp +By following the directions above, you will find yourself with a +number of fonts with unusual names --- with encodings such as +.Dq Li adobe-fontspecific , +.Dq Li microsoft-win3.1 +.Em etc . +In order +to use these fonts with standard applications, it may be useful to +remap them to their proper names. +.Pp +This is done by writing a +.Pa fonts.alias +file. The format of this file +is very simple: it consists of a series of lines each mapping an alias +name to a font name. A +.Pa fonts.alias +file might look as follows: +.Bd -literal +"-ogonki-alamakota-medium-r-normal--0-0-0-0-p-0-iso8859-2" \e + "-ogonki-alamakota-medium-r-normal--0-0-0-0-p-0-adobe-fontspecific" +.Ed +.Pp +(both XLFD names on a single line). The syntax of the +.Pa fonts.alias +file is more precisely described in the +.Lk mkfontdir.1.html mkfontdir(1) +manual page. +.Ss Additional notes about scalable core fonts +.Sy About the FreeType backend +.Pp +The +.Em FreeType +backend (formerly +.Em xfsft ) +is a backend based on version 2 of the FreeType library (see +.Lk http://www.freetype.org/ "the FreeType web site" ) +and has +the X-TT functionalities for CJKV support provided by the After X-TT +Project (see +.Lk http://x-tt.sourceforge.jp/ "the After X-TT Project web site" ) . +The +.Em FreeType +backend has support for the +.Dq fontenc +style of internationalisation (see +.Sx The_fontenc_layer ) . +This backend supports TrueType font files +.Pf ( Pa *.ttf ) , +OpenType font files +.Pf ( Pa *.otf ) , +TrueType Collections +.Pf ( Pa *.ttc ) , +OpenType Collections +.Pf ( Pa *.otc ) +and Type 1 font +files +.Pf ( Pa *.pfa +and +.Pa *.pfb ) . +.Pp +In order to access the faces in a TrueType Collection file, the face +number must be specified in the fonts.dir file before the filename, +within a pair of colons, or by setting the 'fn' TTCap option. For example, +.Bd -literal +:1:mincho.ttc -misc-pmincho-medium-r-normal--0-0-0-0-p-0-jisx0208.1990-0 +.Ed +.Pp +refers to face 1 in the +.Pa mincho.ttc +TrueType Collection file. +.Pp +The new +.Em FreeType +backend supports the extended +.Pa fonts.dir +syntax introduced by X-TrueType with a number +of options, collectively known as +.Dq TTCap . +A +.Dq TTCap +entry follows the +general syntax +.Bd -literal +option=value: +.Ed +.Pp +and should be specified before the filename. The new +.Em FreeType +almost perfectly supports TTCap options that are compatible with X-TT +1.4. The Automatic Italic +.Pf ( Dq Ns Li ai ) , +Double Strike +.Pf ( Dq Ns Li ds ) +and +Bounding box Width +.Pf ( Dq Ns Li bw ) +options are indispensable in CJKV. +For example, +.Bd -literal +mincho.ttc -misc-mincho-medium-r-normal--0-0-0-0-c-0-jisx0208.1990-0 +ds=y:mincho.ttc -misc-mincho-bold-r-normal--0-0-0-0-c-0-jisx0208.1990-0 +ai=0.2:mincho.ttc -misc-mincho-medium-i-normal--0-0-0-0-c-0-jisx0208.1990-0 +ds=y:ai=0.2:mincho.ttc -misc-mincho-bold-i-normal--0-0-0-0-c-0-jisx0208.1990-0 +bw=0.5:mincho.ttc -misc-mincho-medium-r-normal--0-0-0-0-c-0-jisx0201.1976-0 +bw=0.5:ds=y:mincho.ttc -misc-mincho-bold-r-normal--0-0-0-0-c-0-jisx0201.1976-0 +bw=0.5:ai=0.2:mincho.ttc -misc-mincho-medium-i-normal--0-0-0-0-c-0-jisx0201.1976-0 +bw=0.5:ds=y:ai=0.2:mincho.ttc -misc-mincho-bold-i-normal--0-0-0-0-c-0-jisx0201.1976-0 +.Ed +.Pp +setup the complete combination of jisx0208 and jisx0201 using mincho.ttc +only. More information on the TTCap syntax is found on +.Lk http://x-tt.sourceforge.jp/ "the After X-TT Project page" . +.Pp +The +.Em FreeType +backend uses the +.Em fontenc +layer in order to support +recoding of fonts; this was described in +.Sx The_fontenc_layer +and especially +.Sx The_FreeType_backend +earlier in this document. +.Pp +.Sy Delayed glyph rasterisation +.Pp +When loading a proportional fonts which contain a huge number of glyphs, +the old +.Em FreeType +delayed glyph rasterisation until the time at which +the glyph was first used. The new FreeType (libfreetype-xtt2) has an +improved +.Dq very lazy +metric calculation method to speed up the process when +loading TrueType or OpenType fonts. Although the +.Em X-TT +module also +has this method, the +.Pf \(dq Ql vl=y Ns \(dq +TTCap option must be set if you want to +use it. This is the default method for +.Em FreeType +when it loads +multi-byte fonts. Even if you use a unicode font which has tens of +thousands of glyphs, this delay will not be worrisome as long as you use +the new +.Em FreeType +backend -- its +.Dq very lazy +method is super-fast. +.Pp +The maximum error of bitmap position using +.Dq very lazy +method is 1 pixel, +and is the same as that of a character-cell spacing. When the X-TT +backend is used with the +.Dq Li vl=y +option, a chipped bitmap is displayed +with certain fonts. However, the new FreeType backend has minimal problem +with this, since it corrects left- and right-side bearings using +.Dq italicAngle +in the TrueType/OpenType post table, and does automatic +correction of bitmap positions when rasterisation so that chipped bitmaps +are not displayed. Nevertheless if you don't want to use the +.Dq very lazy +method when using multi-bytes fonts, set +.Dq Li vl=n +in the TTCap option to +disable it: +.Bd -literal +vl=n:luxirr.ttf -b&h-Luxi Serif-medium-r-normal--0-0-0-0-p-0-iso10646-1 +.Ed +.Pp +Of course, both backends also support an optimisation for character-cell +fonts (fonts with all glyph metrics equal, or terminal fonts). A font +with an XLFD specifying a character-cell spacing +.Dq Li c , +as in +.Bd -literal +-misc-mincho-medium-r-normal--0-0-0-0-c-0-jisx0208.1990-0 +.Ed +.Pp +or +.Bd -literal +fs=c:mincho.ttc -misc-mincho-medium-r-normal--0-0-0-0-p-0-jisx0208.1990-0 +.Ed +.Pp +will not compute the metric for each glyph, but instead +trust the font to be a character-cell font. You are +encouraged to make use of this optimisation when useful, but be warned +that not all monospaced fonts are character-cell fonts. +.Sh APPENDIX: BACKGROUND AND TERMINOLOGY +.Ss Characters and glyphs +A computer text-processing system inputs keystrokes and outputs +.Em glyphs , +small pictures that are assembled on paper or on a +computer screen. Keystrokes and glyphs do not, in general, coincide: +for example, if the system does generate ligatures, then to the +sequence of two keystrokes +.Pf < Ql f Ns > Ns < Ns Ql i Ns > +will typically +correspond a single glyph. Similarly, if the system shapes Arabic +glyphs in a vaguely reasonable manner, then multiple different glyphs +may correspond to a single keystroke. +.Pp +The complex transformation rules from keystrokes to glyphs are usually +factored into two simpler transformations, from keystrokes to +.Em characters +and from characters to glyphs. You may want to think +of characters as the basic unit of text that is stored +.Em e.g. +in +the buffer of your text editor. While the definition of a character +is intrinsically application-specific, a number of standardised +collections of characters have been defined. +.Pp +A +.Em coded character set +is a set of characters together with a +mapping from integer codes --- known as +.Em codepoints +--- to +characters. Examples of coded character sets include US-ASCII, +ISO\ 8859-1, KOI8-R, and JIS\ X\ 0208(1990). +.Pp +A coded character set need not use 8 bit integers to index characters. +Many early systems used 6 bit character sets, while 16 bit (or more) +character sets are necessary for ideographic writing systems. +.Ss Font files, fonts, and XLFD +Traditionally, typographers speak about +.Em typefaces +and +.Em founts . +A typeface is a particular style or design, such as +Times Italic, while a fount is a molten-lead incarnation of a given +typeface at a given size. +.Pp +Digital fonts come in +.Em font files . +A font file contains the +information necessary for generating glyphs of a given typeface, and +applications using font files may access glyph information in an +arbitrary order. +.Pp +Digital fonts may consist of bitmap data, in which case they are said +to be +.Em bitmap fonts . +They may also consist of a mathematical +description of glyph shapes, in which case they are said to be +.Em scalable fonts . +Common formats for scalable font files are +.Em Type\ 1 +(sometimes incorrectly called +.Em ATM fonts +or +.Em PostScript fonts ) , +.Em TrueType +and +.Em OpenType . +.Pp +The glyph data in a digital font needs to be indexed somehow. How +this is done depends on the font file format. In the case of +Type\ 1 fonts, glyphs are identified by +.Em glyph names . +In the +case of TrueType fonts, glyphs are indexed by integers corresponding +to one of a number of indexing schemes (usually Unicode --- see below). +.Pp +The X11 core fonts system uses the data in a font file to generate +.Em font instances , +which are collections of glyphs at a given size +indexed according to a given encoding. +.Pp +X11 core font instances are usually specified using a notation known +as the +.Em X Logical Font Description +(XLFD). An XLFD starts with a +dash +.Dq Li - , +and consists of fourteen fields separated by dashes, +for example: +.Bd -literal +-adobe-courier-medium-r-normal--12-120-75-75-m-70-iso8859-1 +.Ed +.Pp +Or particular interest are the last two fields +.Dq Li iso8859-1 , +which +specify the font instance's encoding. +.Pp +A scalable font is specified by an XLFD which contains zeroes instead +of some fields: +.Bd -literal +-adobe-courier-medium-r-normal--0-0-0-0-m-0-iso8859-1 +.Ed +.Pp +X11 font instances may also be specified by short name. Unlike an +XLFD, a short name has no structure and is simply a conventional name +for a font instance. Two short names are of particular interest, as +the server will not start if font instances with these names cannot be +opened. These are +.Dq Li fixed , +which specifies the fallback font to +use when the requested font cannot be opened, and +.Dq Li cursor , +which +specifies the set of glyphs to be used by the mouse pointer. +.Pp +Short names are usually implemented as aliases to XLFDs; the +standard +.Dq Li fixed +and +.Dq Li cursor +aliases are defined in +.Bd -literal +/usr/share/font/X11/misc/fonts.alias +.Ed +.Ss Unicode +Unicode +.Pf ( Lk http://www.unicode.org http://www.unicode.org ) +is a coded character +set with the goal of uniquely identifying all characters for all +scripts, current and historical. While Unicode was explicitly not +designed as a glyph encoding scheme, it is often possible to use it as +such. +.Pp +Unicode is an +.Em open +character set, meaning that codepoint +assignments may be added to Unicode at any time (once specified, +though, an assignment can never be changed). For this reason, a +Unicode font will be +.Em sparse , +meaning that it only defines glyphs +for a subset of the character registry of Unicode. +.Pp +The Unicode standard is defined in parallel with the international +standard ISO\ 10646. Assignments in the two standards are always +equivalent, and we often use the terms +.Em Unicode +and +.Em ISO\ 10646 +interchangeably. +.Pp +When used in the X11 core fonts system, Unicode-encoded fonts should +have the last two fields of their XLFD set to +.Dq Li iso10646-1 . +.Sh REFERENCES +X11R6 comes with extensive documentation in the form of manual +pages and typeset documents. Before installing fonts, you really should +read the +.Lk fontconfig.3.html fontconfig(3) +and +.Lk mkfontdir.1.html mkfontdir(1) +manual pages; other +manual pages of interest include +.Lk X.7.html X(7) , +.Lk Xserver.1.html Xserver(1) , +.Lk xset.1.html xset(1) , +.Lk Xft.3.html Xft(3) , +.Lk xlsfonts.1.html xlsfonts(1) +and +.Lk showfont.1.html showfont(1) . +In addition, you may want to read the +.Lk xlfd "X Logical Font Description document" +.Pq xlfd +by Jim Flowers. +.Pp +The +.Lk http://www.faqs.org/faqs/by-newsgroup/comp/comp.fonts.html "comp.fonts FAQ" , +which is unfortunately no longer being maintained, contains a wealth +of information about digital fonts. +.Pp +Xft and Fontconfig are described on +.Lk http://www.fontconfig.org "the Fontconfig site" . +.Pp +The +.Lk http://www.dcs.ed.ac.uk/home/jec/programs/xfsft/ "xfsft home page" +has been superseded by this document, and is now obsolete; you may +however still find some of the information that it contains useful. +.Lk http://www.joerg-pommnitz.de/TrueType/xfsft.html "Joerg Pommnitz' xfsft page" +is the canonical source for the +.Dq Nm ttmkfdir +utility, which is the +ancestor of +.Nm mkfontscale . +.Pp +.Lk http://www.pps.jussieu.fr/~jch/software/ "The author's software pages" +might or might not contain related scribbles and development versions +of software. +.Pp +The documentation of +.Em X-TrueType +is available from +.Lk http://x-tt.sourceforge.jp/ "the After X-TT Project page" . +.Pp +While the +.Lk http://www.unicode.org "Unicode consortium site" +may be of interest, you are more likely to find what you need in +Markus Kuhn's +.Lk http://www.cl.cam.ac.uk/~mgk25/unicode.html "UTF-8 and Unicode FAQ" . +.Pp +The IETF RFC documents, available from a number of sites throughout +the world, often provide interesting information about character set +issues; see for example +.Lk https://datatracker.ietf.org/doc/rfc373/ "RFC\e373" . +.Sh AUTHORS +.An -nosplit +X Version 11, Release 6 +.An Juliusz Chroboczek Aq Mt jch@freedesktop.org |