Fonts in the X Window System

Fonts in the X Window System
Fonts in the X Window System
Last updates:
Thu Oct 11 17:25:23 2001
Thu Sep 13 16:43:57 2007
Table of contents
X11 font formats
Font utilities
How X11 fonts are found
European language fonts
Asian language fonts
Unicode fonts
Font file names
Font servers
X server font access and file permissions
X terminals and X11 fonts
X11 font formats
Last update:
[20-Nov-1997]
Fonts in the X Window System are available in these bitmap
forms,
.bdf
(binary distribution format)
.pcf
(portable compiled format)
.snf
(server normal format)
and on some systems, as outline fonts:
.f3b
(Sun Microsystems' proprietary outline
font format)
.pfa
(Adobe Type 1 PostScript Font ASCII)
.pfb
(Adobe Type 1 PostScript Font Binary)
.spd
(Bitstream Speedo outline font format)
The
.snf
format is considered obsoleted, having
been replaced by the
.pcf
format; however, many
of our local systems still use the
.snf
format.
Outline fonts need to be rasterized into specific sizes;
this may be done on-the-fly in the X server, or via a remote
font server.
More information on font formats can be found in the GNU
Font Utilities documentation in the
emacs info
and
xinfo
systems.
Font utilities
The utilities
dxfc
bdftopcf
and
bdftosnf
convert between some of these formats, but converters for
several font file format combinations are lacking.
getbdf
can fetch a font from the X server,
and output it in
.bdf
format. Since there
are converters from this format to the others, this
utility makes it possible to convert between any pair of
formats, albeit by a roundabout route through the X
server.
bdfresize
can be used to scale a font in
.bdf
format by
a rational factor. The output is also a
.bdf
file, but before you can use it, you need to edit the FONT
line in the output file to change the font name to reflect
the altered size.
showsnf
can be used to print the contents of an
.snf
file.
mftobdf
can be used to convert Metafont fonts to
.bdf
format.
The
fstobdf
utility can read any font from a font server, and output
it in
.bdf
format
The
xfd
utility displays a table of all characters in a font, for
example,
xfd -fn 10x20
The
xlsfonts
utility lists all of the fonts known to the X server. On
many systems, this will produce a long list of 1000--2000
fonts, so if you use it, you probably want to filter its
output through a pager, like
less
more
, or
pg
, or else
through a pattern search utility like
agrep
cgrep
ceegrep
egrep
fgrep
grep
, or
sgrep
There is a very nice BDF font editor developed at New
Mexico State University,
xmbdfed
. It has
a Web page at
with pointers to source code and precompiled binary
executable distributions for GNU/Linux, Microsoft Windows
NT 4.0, and Sun Solaris 2.x.
How X11 fonts are found
Fonts are found in a directory path established by the
xset
command,
and once the directories have been established, it is
necessary to run
xset fp rehash
to force the
X server to read all of the directories and load up the
names of fonts found in them:
% xset fp+ /usr/local/share/lib/X11/fonts/European
% xset fp+ /usr/openwin/lib/X11/fonts/F3
% xset fp+ /usr/dt/config/xfonts
% xset fp rehash
The
fp+
option adds the directory to the
end
of the current list, which was originally
established by a command in your
.xinitrc
or
.xsession
file.
The
fp+
option adds the directory to the
end
If required, you can add a directory to the front
of the search path by using
+fp
instead.
You can find out what the current font path is like this:
% xset q
Keyboard Control:
...
Pointer Control:
...
Screen Saver:
...
Colors:
...
Font Path:
/usr/openwin/lib/X11/fonts/F3/,
/usr/openwin/lib/X11/fonts/F3bitmaps/,
/usr/openwin/lib/X11/fonts/Type1/,
/usr/openwin/lib/X11/fonts/Speedo/,
/usr/openwin/lib/X11/fonts/misc/,
/usr/openwin/lib/X11/fonts/75dpi/,
/usr/openwin/lib/X11/fonts/100dpi/,
/usr/openwin/lib/X11/fonts/Xt+/,
/usr/dt/config/xfonts/C,
/usr/dt/config/xfonts/C,
/usr/local/share/lib/amaya/amaya-1.0b/Thot/fonts/,
/usr/local/share/lib/X11/fonts/100dpi,
/usr/local/share/lib/X11/fonts/European,
/usr/local/share/lib/X11/fonts/Ethiopic,
/usr/local/share/lib/X11/fonts/Asian,
/usr/local/share/lib/X11/fonts/waterloo,
/usr/local/share/lib/X11/fonts/Korean,
/usr/local/share/lib/X11/fonts/Chinese,
/usr/local/share/lib/X11/fonts/Chinese-BIG,
/usr/local/share/lib/X11/fonts/Japanese,
/usr/local/share/lib/X11/fonts/Japanese-BIG,
/usr/local/share/lib/X11/fonts/Misc
Notice that there are many common directory paths in this
list. That is a clue about where to find other fonts. For
example,
% ls -F /usr/dt/config/xfonts/
C/ ja/ ko/ tchinese@ zh_TW/
chinese@ japanese@ korean@ zh/

% ls -F /usr/local/share/lib/X11/fonts/
100dpi/ Ethiopic/ Korean/ cyrillic/ ncd/
75dpi/ European/ Misc/ dec/ pcfonts/
Asian/ European-BIG/ axfonts/ fonts/ waterloo/
Chinese/ Japanese/ chinese/ hds/
Chinese-BIG/ Japanese-BIG/ cm/ misc/

% ls -F /usr/openwin/lib/X11/fonts
100dpi/ F3/ Speedo/ Type3/ encodings/
75dpi/ F3bitmaps/ Type1/ Xt+/ misc/
Because most users will use only a rather small number of
fonts, their font paths may be rather short. Nevertheless,
if you want to take advantage of additional fonts, you
should be prepared to investigate the local offerings with
suitable
ls -F
commands as shown above.
European language fonts
Most computer users in the Western World are accustomed to
the ASCII or ISO8859-1 Latin 1 character sets, which are
standard on computer keyboards (except in the IBM mainframe
world). ISO8859-1 is the standard character set used in
HTML, the document markup language used on the World-Wide
Web.
These character sets offer 128 or 256 characters, which is
usually enough for languages such as English, French,
German, Danish, .... However, when the accented characters
of the European languages are enumerated, then 256
characters are insufficient, and consequently, there are
several character set variants, sometimes called
code
pages
, in the ISO8859 Standard which have common
lower-128 character assignments, but differ in the upper
128:
ISO8859-0
Latin alphabet No. 0 [old proposal, since replaced by
ISO 8859-14 and ISO 8859-15, see below].
ISO8859-1
Latin alphabet No. 1: Western Europe (Danish, Dutch,
English, Faeroese, Finnish, Flemish, French, German,
Icelandic, Irish, Italian, Norwegian, Portuguese,
Spanish, and Swedish). Many other languages can be
written in this character set, including Hawaiian,
Indonesian, and Swahili.
ISO8859-2
Latin alphabet No. 2: Eastern Europe (Czechoslovakian,
English, German, Hungarian, Polish, Rumanian,
Serbo-Croatian, Slovak, Slovene).
ISO8859-3
Latin alphabet No. 3: (English, Esperanto, Galician,
Maltese and Turkish). Use for Turkish is deprecated,
in favor of ISO8859-9 (see below).
ISO8859-4
Latin alphabet No. 4: (English, Baltic languages
(Estonian, Latvian, Lithuanian), and Scandinavian
languages (Danish, Faeroese, Icelandic, Lappish,
Norwegian, and Swedish)).
ISO8859-5
Latin/Cyrillic alphabet: (Bulgarian, Byelorussian,
English, (Slavic) Macedonian, Russian, Serbian,
Ukrainian (up to 1990)).
ISO8859-6
Latin/Arabic alphabet: (English, Arabic).
ISO8859-7
Latin/Greek alphabet: (English, Greek).
ISO8859-8
Latin/Hebrew alphabet: (English, Hebrew).
ISO8859-9
Latin alphabet No. 5: (Danish, Dutch, English,
Finnish, French, German, Irish, Italian, Norwegian,
Portuguese, Spanish, Swedish, Turkish), formed by
extending ISO8859-1 with additional characters from
Icelandic and Turkish.
ISO8859-10
Latin alphabet No. 6: Nordic alphabets: Modification
of ISO8859-4 to include characters needed for Sami.
ISO8859-11
Latin/Thai alphabet.
ISO8859-12
Not yet assigned.
ISO8859-13
Latin alphabet No. 7 (Baltic Rim).
ISO8859-14
Latin alphabet No. 8 (Celtic); see ISO/IEC
8859-14:1998 (E) at
for details.
ISO8859-15
Latin alphabet No. 9 (similar to Latin-1, with euro
and oe ligature); see the FDIS for ISO/IEC
8859-15:1998 (E) document at
and
for details.
ISO8859-16
Latin alphabet No. 10: (Albanian, Croatian, English,
Finnish, French, German, Hungarian, Irish Gaelic (new
orthography), Italian, Latin, Polish, Romanian, and
Slovenian).
More details on these character sets, and some amusing
comments on their history, can be found at
Roman Czyborra's Web site.
Within the limitations of an 8-bit character set, there
are a great many `code pages', that is, assignments of
particular glyphs to entries in a 256-character table,
with the glyph set chosen to be important for a particular
language or region. For an extensive listing of such code
tables, follow this link to
IBM's code page compendium.
For information about pre-1980 computer character sets,
see the excellent book
@String{
pub-AW
= "Ad{\-d}i{\-s}on-Wes{\-l}ey"}

@String{
pub-AW:adr
= "Reading, MA, USA"}

@Book{
Mackenzie:CCS80
author = "Charles E. Mackenzie",
title = "Coded Character Sets: History and Development",
publisher =
pub-AW
address =
pub-AW:adr
pages = "xxi + 513",
year = "1980",
ISBN = "0-201-14460-3",
LCCN = "QA268 .M27 1980",
bibdate = "Wed Dec 15 10:38:43 1993",
price = "US\$24.95",
series = "The Systems Programming Series",
Asian language fonts
Chinese, Japanese, and Korean pose a much larger problem for
font designers and font software, because each requires
several thousand characters.
The X Window System font file formats can support up to
65,536 characters in a font, but not all font software works
properly with these fonts. In particular, on Sun
Microsystems systems,
/usr/openwin/bin/xfd
will
display only the first 256 characters in such a font. You
need to use
/usr/local/X11R5/bin/xfd
to view
such fonts.
Until recently, vendor support of Asian language fonts was
spotty, at least in the vendors of the systems normally sold
in North America. Fortunately, the Free Software Foundation
has collected a large number of international fonts
contributed by many individuals and companies around the
world, and our local systems now have all of them available
for use.
The sample listing above for the directory
/usr/local/share/lib/X11/fonts/
shows
subdirectories containing fonts for Chinese, Japanese,
Korean, ISO-8859-n European, Asian (Devanagiri, Lao,
Tibetan, and Thai), Arabic, and Hebrew. Some of these are
still incomplete (notably, Devanagiri), and there is still
no coverage of the scripts required by most the major
languages of India, nor of Persian and Urdu, nor of any of
the south-central Asian languages, such as Georgian.
Unicode fonts
Roman Czyborra has developed prototype
Unicode
fonts for the X Window System: see
for details.
Markus Kuhn has developed prototype ISO10646-1 (Unicode) fonts
for the X Window System; see
for details.
Microsoft maintains a comprehensive Web site on Unicode-related
issues at
More information on Unicode fonts is available here:
Font file names
Fonts in the X Window System have long descriptive names,
but such names are often inconvenient to type, so provisions
are made for aliases.
Each X11 font directory contains one or two additional files
beside the font files:
fonts.dir
and
fonts.alias
The
fonts.dir
file is created by the
mkfontdir
utility, which reads all of the font files in the
directory and extracts their long names. A typical file
looks like this:
% cd /usr/local/share/lib/X11/fonts/Asian
% head -5 fonts.dir
14
mule-indian-24.pcf -misc-fixed-medium-r-normal--24-240-72-72-c-120-muleindian-2
thai-16.pcf -misc-fixed-medium-r-normal--16-160-72-72-m-80-tis620.2529-1
thai-14.pcf -misc-fixed-medium-r-normal--14-140-72-72-m-70-tis620.2529-1
thai-24.pcf -misc-fixed-medium-r-normal--24-240-72-72-c-120-tis620.2529-1
The first line contains a font count, and the remaining
lines consist of a file name, and a long font name.
The
fonts.alias
file is created by a human, and
consists of lines with a short name and a full name, for
example:
% cd /usr/local/share/lib/X11/fonts
% cat fonts.alias
a14 -ETL-Fixed-Medium-R-Normal--14-140-72-72-C-70-ISO8859-1
a16 -ETL-Fixed-Medium-R-Normal--16-160-72-72-C-80-ISO8859-1
a24 -ETL-Fixed-Medium-R-Normal--24-240-72-72-C-120-ISO8859-1
Thus, you should use the second of these fonts in an X
terminal session like this:
% xterm -fn a14 &
or like this:
% xterm -fn -ETL-Fixed-Medium-R-Normal--14-140-72-72-C-70-ISO8859-1 &
Alternatively, you can switch to such a font in an X
terminal selection by getting the font name into the X
selection buffer (e.g. by a copy operation in the
emacs
text
editor, or in an
xfontsel
window), then using Ctrl-Right-MouseButton to popup the
VT Fonts
menu, and from it select the last item,
labelled
Selection
. This can be convenient if
you need to temporarily switch fonts, such as to read an
e-mail message in a different character set.
You can find further details of the X Window System font
naming conventions in the
X11
UNIX
manual pages.
Font servers
In order to address some of the deficiencies of font
handling in the X Window System, among them the need to
propagate many megabytes of font files to each client
system, and to rasterize outline fonts into bitmap fonts
on-the-fly, X11R5 introduced the idea of
font
servers
While font servers may indeed work adequately at sites with
all machines purchased from a single UNIX vendor, the
experience at our site, which has more than a hundred
workstations representing 5 vendors, 8 operating systems,
and dozens of hardware models, is that font servers tend to
cause hard-to-debug hangs of client systems, and therefore,
we choose not to run them. Instead, we simply provide the
font files in a common NFS-mounted directory that is
accessible to all of our systems. This avoids file space
replication, and greatly facilitates maintenance and update
of the font collection.
X server font
access and file permissions
The X server, which is responsible for rendering fonts,
normally runs as the root user, rather than as the
logged-in user. In most cases, this is transparent to the
human user. However, if there are directories in the font
path which reside on another system, and those
directories, or files in them, lack world read access,
then the X server will not be able to read them,
even
if the human user can
X terminals and X11 fonts
X terminals are low-cost workstations that run a simplified
UNIX-like operating system that is just sufficient to
support running an X server, but no user processes.
X terminals usually have no disks, and therefore, no file
system.
X terminals may be configured so that the user automatically
logs in on a specific remote system, or they may be
configured to offer a menu of assorted remote hosts that the
user can select from before logging in.
X terminals store a very small set of fonts in read-only
nonvolatile memory, and then when they are powered on, or
rebooted, they fetch their operating system and other
needed fonts from a remote server machine. Because they
do not have user accounts on the remote server, there is
no password authentication possible, so they get their
data via TFTP (Trivial File Transfer Protocol), or via a
mount of a memory-mapped read-only NFS (Network File
System) tree.
For both TFTP and NFS access, remote servers drastically
limit the part of the file system that the X terminals can
see, usually just to a small file directory tree provided
by the X terminal vendor. For security reasons, this tree
does not permit symbolic links to other files or
directories outside the tree.
This practice has a
significant
impact on users who
want to use additional X11 fonts:
Since the only files the X terminal can see are those in
its remote TFTP tree, unless local system management has
copied the normal X11 fonts into that tree, the X
terminal user will not be able to access them.
Users who have private collections of X11 fonts will be
entirely unable to access them from an X terminal,
whereas they could do so without problems from an ordinary
UNIX workstation.
If your site has X terminals from multiple vendors, then
their TFTP trees and thus, font collections, will
differ.
In the second case, your only recourse is to ask your system
management to add your personal X11 font collection to the X
terminal TFTP trees.
If I login to a local X terminal (an HDS ViewStation) and
run
xset q
, here is what I get for a font path:
% xset q
...
Font Path:
/builtin/,
/hds/fonts/100dpi/,
/hds/fonts/75dpi/,
/hds/fonts/Asterx2.1/,
/hds/fonts/Asterx3.0/,
/hds/fonts/Xol/,
/hds/fonts/lotus123/,
/hds/fonts/misc/,
/hds/fonts/softpc/,
/hds/fonts/wp5.1/,
/hds/fonts/international/,
/hds/fonts/tn/,
/hds/local/fonts/decwin/100dpi/,
/hds/local/fonts/decwin/75dpi/
The path
/hds
represents the root of the TFTP
tree, which actually corresponds to the UNIX file path
/export/local/netOS/2.0.2
on a local file
server.
To solve these problems, at the University of Utah Center
for Scientific Computing facilities in the Mathematics
Department, we are making rearrangements in the NCD and
HDS/Neoware X terminal TFTP trees, and the normal shared X11
font tree,
/usr/local/share/lib/X11/fonts
, to
ensure that the same set of fonts is available in all of
them. However, as of the time of writing this
[21-Nov-1997], the work is still in progress.