TTF2PT1 - A True Type to PostScript Type 1 Font Converter
(Do not edit this file, it is generated from README.html!!!)
[
Based on ttf2pfa by Andrew Weeks, and help from Frank Siegert.
Modification by Mark Heath.
Further modification by Sergey Babkin.
The Type1 assembler by I. Lee Hetherington with modifications by
Kai-Uwe Herbing.
]
Ever wanted to install a particular font on your XServer but only could find
the font you are after in True Type Format?
Ever asked comp.fonts for a True Type to Type 1 converter and got a List
of Commercial software that doesn't run on your Operating System?
Well, this program should be the answer. This program is written in C (so it
should be portable) and therefore should run on any OS. The only limitation
is that the program requires some method of converting Big endian integers into
local host integers so the network functions ntohs and ntohl are used. These
can be replaced by macros if your platform doesn't have them.
Of course the target platform requires a C compiler and command line ability.
Ttf2pt1 is a font converter from the True Type format (and some other formats
supported by the FreeType library as well) to the Adobe Type1 format.
The versions 3.0 and later got rather extensive post-processing algorithm that
brings the converted fonts to the requirements of the Type1 standard, tries to
correct the rounding errors introduced during conversions and some simple
kinds of bugs that are typical for the public domain TTF fonts. It
also generates the hints that enable much better rendering of fonts in
small sizes that are typical for the computer displays. But everything
has its price, and some of the optimizations may not work well for certain
fonts. That's why the options were added to the converter, to control
the performed optimizations.
The converter is simple to run, just:
ttf2pt1 [-options] ttffont.ttf [Fontname]
or
ttf2pt1 [-options] ttffont.ttf -
The first variant creates the file Fontname.pfa (or Fontname.pfb if the
option '-b' was used) with the converted font and Fontname.afm with the
font metrics, the second one prints the font or another file (if the option
'-G' was used) on the standard output from where it can be immediately
piped through some filter. If no Fontname is specified for the first
variant, the name is generated from ttffont by replacing the .ttf
filename suffix.
Most of the time no options are neccessary (with a possible exception
of '-e'). But if there are some troubles with the resulting font, they
may be used to control the conversion.
The options are:
-a - Include all the glyphs from the source file into the converted
file. If this option is not specified then only the glyphs that have
been assigned some encoding are included, because the rest of glyphs
would be inaccessible anyway and would only consume the disk space.
But some applications are clever enough to change the encoding on
the fly and thus use the other glyphs, in this case they could
benefit from using this option. But there is a catch: the X11 library
has rather low limit for the font size. Including more glyphs increases
the file size and thus increases the chance of hitting this limit.
See app/X11/README for the description of a
patch to X11 which fixes this problem.
-b - Encode the resulting font to produce a ready .pfb file.
-d suboptions - Debugging options. The suboptions are:
a - Print out the absolute coordinates of dots in outlines. Such
a font can not be used by any program (that's why this option is
incompatible with '-e') but it has proven to be a valuable debuging
information.
r - Do not reverse the direction of outlines. The TTF fonts have
the standard direction of outlines opposite to the Type1 fonts. So
they should be reversed during proper conversion. This option
may be used for debugging or to handle a TTF font with wrong
direction of outlines (possibly, converted in a broken way from
a Type1 font). The first signs of the wrong direction are the
letters like "P" or "B" without the unpainted "holes" inside.
-e - Assemble the resulting font to produce a ready .pfa file.
[ S.B.: Personally I don't think that this option is particularly useful.
The same result may be achieved by piping the unassembled data
through t1asm, the Type 1 assembler. And, anyways, it's good to
have the t1utils package handy. But Mark and many users think that
this functionality is good and it took not much time to add this option. ]
-F - Force the Unicode encoding: any type of MS encoding specified
in the font is ignored and the font is treated like it has Unicode
encoding. WARNING: this option is intended for buggy fonts
which actually are in Unicode but are marked as something else. The
effect on the other fonts is unpredictable.
-G suboptions - File generation options. The suboptions may be lowercase
or uppercase, the lowercase ones disable the generation of particular
files, the corresponding uppercase suboptions enable the generation of the
same kind of files. If the result of ttf2pt1 is requested to be printed on
the standard output, the last enabling suboption of -G determines
which file will be written to the standard output and the rest of files
will be discarded. For example, -G A will request the AFM file.
The suboptions to disable/enable the generation of the files are:
f/F - The font file. Depending on the other options this file
will have one of the suffixes .t1a, .pfa or .pfb. If the conversion result
is requested on the standard output ('-' is used as the output file name)
then the font file will also be written there by default, if not overwritten
by another suboption of -G.
Default: enabled
a/A - The Adobe font metrics file (.afm).
Default: enabled
e/E - The dvips encoding file (.enc).
Default: disabled
-l language[+argument] - Extract the fonts for the specified language from a
multi-language Unicode font. If this option is not used the converter
tries to guess the language by the values of the shell variable LANG.
If it is not able to guess the language by LANG it tries all the
languages in the order they are listed.
After the plus sign an optional argument for the language extractor
may be specified. The format of the argument is absolutely up to
the particular language converter. The primary purpose of the
argument is to support selection of planes for the multi-plane
Eastern encodings but it can also be used in any other way. The
language extractor may decide to add the plane name in some form
to the name of the resulting font. None of the currently supported
languages make any use of the argument yet.
As of now the following languages are supported:
latin1 - for all the languages using the Latin-1 encoding
latin2 - for the Central European languages
latin4 - for the Baltic languages
latin5 - for the Turkish language
cyrillic - for the languages with Cyrillic alphabet
russian - historic synonym for cyrillic
bulgarian - historic synonym for cyrillic
adobestd - for the AdobeStandard encoding used by TeX
plane+argument - to select one plane from a multi-byte encoding
The argument of the "plane" language may be in one of three forms:
plane+pid=<pid>,eid=<eid>
plane+pid=<pid>,eid=<eid>,<plane_number>
plane+<plane_number>
Pid (TTF platform id) and eid (TTF encoding id) select a particular
TTF encoding table in the original font. They are specified as decimal
numbers. If this particular encoding table is not present in the font
file then the conversion fails. The native ("ttf") front-end parser supports
only pid=3 (Windows platform), the FreeType-based ("ft") front-end supports
any platform. If pid/eid is not specified then the TTF encoding table is
determined as usual: Unicode encoding if it's first or an 8-bit encoding
if not (and for an 8-bit encoding the plane number is silently ignored).
To prevent the converter from falling back to an 8-bit encoding, specify
the Unicode pid/eid value explicitly.
Plane_number is a hexadecimal (if starts with "0x") or decimal number.
It gives the values of upper bytes for which 256 characters will be
selected. If not specified, defaults to 0. It is also used as a font
name suffix (the leading "0x" is not included into the suffix).
NOTE:
It seems that many Eastern fonts use features of the TTF format that are
not supported by the ttf2pt1's built-in front-end parser. Because of
this for now we recommend using the FreeType-based parser (option
'-p ft') with the "plane" language.
NOTE:
You may notice that the language names are not uniform: some are the
names of particular languages and some are names of encodings. This
is because of the different approaches. The original idea was to
implement a conversion from Unicode to the appropriate Windows
encoding for a given language. And then use the translation tables
to generate the fonts in whatever final encodings are needed. This
would allow to pile together the Unicode fonts and the non-Unicode
Windows fonts for that language and let the program to sort them out
automatically. And then generate fonts in all the possible encodings
for that language. An example of this approach is the Russian language
support. But if there is no multiplicity of encodings used for some
languages and if the non-Unicode fonts are not considered important
by the users, another way would be simpler to implement: just provide
only one table for extraction of the target encoding from Unicode
and don't bother with the translation tables. The latin* "languages"
are examples of this approach. If somebody feels that he needs the
Type1 fonts both in Latin-* and Windows encodings he or she is absolutely
welcome to submit the code to implement it.
WARNING:
Some of the glyphs included into the AdobeStandard encoding are not
included into the Unicode standard. The most typical examples of such
glyphs are ligatures like 'fi', 'fl' etc. Because of this the font
designers may place them at various places. The converter tries to
do its best, if the glyphs have honest Adobe names and/or are
placed at the same codes as in the Microsoft fonts they will be
picked up. Otherwise a possible solution is to use the option '-L'
with an external map.
-L file[+[pid=<pid>,eid=<eid>,][plane]] - Extract the fonts for the specified
language from a multi-language font using the map from this file. This is
rather like the option '-l' but the encoding map is not
compiled into the program, it's taken from that file, so it's
easy to edit. Examples of such files are provided in
maps/adobe-standard-encoding.map, CP1250.map. (NOTE:
the 'standard encoding' map does not include all the glyphs of the
AdobeStandard encoding, it's provided only as an example.) The
description of the supported map formats is in the file
maps/unicode-sample.map.
Likewise to '-l', an argument may be specified after the map file
name. But in this case the argument has fixed meaning: it selects the
original TTF encoding table (the syntax is the same as in '-l plane')
and/or a plane of the map file. The plane name also gets added after dash
to the font name. The plane is a concept used in the Eastern fonts with big
number of glyphs: one TTF font gets divided into multiple Type1 fonts,
each containing one plane of up to 256 glyphs. But with a little
creativity this concept may be used for other purposes of combining
multiple translation maps into one file. To extract multiple planes
from a TTF font ttf2pt1 must be run multiple times, each time with
a different plane name specified.
The default original TTF encoding table used for the option '-L' is
Unicode. The map files may include directives to specify different original
TTF encodings. However if the pid/eid pair is specified with
it overrides any original encoding specified in the map file.
-m type=value - Set maximal or minimal limits of resources.
These limits control the the font generation by limiting the resources
that the font is permitted to require from the PostScript interpreter.
The currently supported types of limits are:
h - the maximal hint stack depth for the substituted hints.
The default value is 128, according to the limitation in X11. This seems to
be the lowest (and thus the safest) widespread value. To display the
hint stack depth required by each glyph in a .t1a file use the script
scripts/cntstems.pl.
-O suboptions - Outline processing options. The suboptions
may be lowercase or uppercase, the lowercase ones disable the features,
the corresponding uppercase suboptions enable the same features.
The suboptions to disable/enable features are:
b/B - Guessing of the ForceBold parameter. This parameter helps
the Type1 engine to rasterize the bold fonts properly at small sizes.
But the algorithm used to guess the proper value of this flag makes
that guess based solely on the font name. In rare cases that may cause
errors, in these cases you may want to disable this guessing.
Default: enabled
h/H - Autogeneration of hints. The really complex outlines
may confuse the algorithm, so theoretically it may be useful
sometimes to disable them. Although up to now it seems that
even bad hints are better than no hints at all.
Default: enabled
u/U - Hint substitution. Hint substitution is a technique
permitting generation of more detailed hints for the rasterizer. It allows
to use different sets of hints for different parts of a glyph and change
these sets as neccessary during rasterization (that's why "substituted").
So it should improve the quality of the fonts rendered at small sizes.
But there are two catches: First, the X11 library has rather low limit for
the font size. More detailed hints increase the file size and thus increase
the chance of hitting this limit (that does not mean that you shall hit it
but you may if your fonts are particularly big). This is especially
probable for Unicode fonts converted with option '-a', so you may want to
use '-a' together with '-Ou'. See app/X11/README for the description of
a patch to X11 which fixes this problem. Second, some rasterizers (again,
X11 is the typical example) have a limitation for total number of hints
used when drawing a glyph (also known as the hint stack depth). If that
stack overflows the glyph is ignored. Starting from version 3.22 ttf2pt1
uses algorithms to minimizing this depth, with the trade-off of slightly
bigger font files. The glyphs which still exceed the limit set by option
'-mh' have all the substituted hints removed and only base hints left.
The algorithms seem to have been refined far enough to make the fonts with
substituted hints look better than the fonts without them or at least the
same. Still if the original fonts are not well-designed the detailed
hinting may emphasize the defects of the design, such as non-even thickness
of lines. So provided that you are not afraid of the X11 bug the best idea
would be to generate a font with this feature and without it, then compare
the results using the program other/cmpf (see the description
in other/README) and decide which one looks better.
Default: enabled
o/O - Space optimization of the outlines' code. This kind of optimization
never hurts, and the only reason to disable this feature is for comparison
of the generated fonts with the fonts generated by the previous versions of
converter. Well, it _almost_ never hurts. As it turned out there exist
some brain-damaged printers which don't understand it. Actually this
feature does not change the outlines at all. The Type 1 font manual
provides a set of redundant operators that make font description shorter,
such as '10 hlineto' instead of '0 10 rlineto' to describe a horizontal
line. This feature enables use of these operators.
Default: enabled
s/S - Smoothing of outlines. If the font is broken in some
way (even the ones that are not easily noticeable), such smoothing
may break it further. So disabling this feature is the first thing to be
tried if some font looks odd. But with smoothing off the hint generation
algorithms may not work properly too.
Default: enabled
t/T - Auto-scaling to the 1000x1000 Type1 standard matrix. The
TTF fonts are described in terms of an arbitrary matrix up to
4000x4000. The converted fonts must be scaled to conform to
the Type1 standard. But the scaling introduces additional rounding
errors, so it may be curious sometimes to look at the font in its
original scale.
Default: enabled
v/V - Do vectorization on the bitmap fonts. Functionally
"vectorization" is the same thing as "autotracing", a different word is
used purely to differentiate it from the Autotrace library. It tries to
produce nice smooth outlines from bitmaps. This feature is still a work
in progress though the results are already mostly decent.
Default: disabled
w/W - Glyphs' width corection. This option is designed to be
used on broken fonts which specify too narrow widths for the
letters. You can tell that a font can benefit from this option
if you see that the characters are smashed together without
any whitespace between them. This option causes the converter
to set the character widths to the actual width of this character
plus the width of a typical vertical stem. But on the other hand
the well-designed fonts may have characters that look better if
their widths are set slightly narrower. Such well-designed fonts
will benefit from disabling this feature. You may want to convert
a font with and without this feature, compare the results and
select the better one. This feature may be used only on proportional
fonts, it has no effect on the fixed-width fonts.
Default: disabled
z/Z - Use the Autotrace library on the bitmap fonts. The results
are horrible and the use of this option is not recommended. This option is
present for experimental purposes. It may change or be removed in the
future. The working tracing can be achieved with option -OV.
Default: disabled
-p parser_name - Use the specified front-end parser to read the font file.
If this option is not used, ttf2pt1 selects the parser automatically based
on the suffix of the font file name, it uses the first parser in its
list that supports this font type. Now two parsers are supported:
ttf - built-in parser for the ttf files (suffix .ttf)
bdf - built-in parser for the BDF files (suffix .bdf)
ft - parser based on the FreeType-2 library (suffixes .ttf,
.otf, .pfa, .pfb)
The parser ft is NOT linked in by default. See Makefile
for instructions how to enable it. We do no support this parser on
Windows: probably it will work but nobody tried and nobody knows how
to build it.
The conversion of the bitmap fonts (such as BDF) is simplistic yet,
producing jagged outlines. When converting such fonts, it might be
a good idea to turn off the hint substitution (using option -Ou)
because the hints produced will be huge but not adding much to the
quality of the fonts.
-u number - Mark the font with this value as its
UniqueID. The UniqueID is used by the printers with the hard disks
to cache the rasterized characters and thus significantly
speed-up the printing. Some of those printers just can't
store the fonts without UniqueID on their disk.The problem
is that the ID is supposed to be unique, as it name says. And
there is no easy way to create a guaranteed unique ID. Adobe specifies
the range 4000000-4999999 for private IDs but still it's difficult
to guarantee the uniqueness within it. So if you don't really need the
UniqueID don't use it, it's optional. Luckily there are a few millions of
possible IDs, so the chances of collision are rather low.
If instead of the number a special value 'A' is given
then the converter generates the value of UniqueID automatically,
as a hash of the font name. (NOTE: in the version 3.22 the
algorithm for autogeneration of UniqueID was changed to fit the values
into the Adobe-spacified range. This means that if UniqueIDs were used
then the printer's cache may need to be flushed before replacing the
fonts converted by an old version with fonts converted by a newer version).
A simple way to find if any of the fonts in a given directory have
duplicated UniqueIDs is to use the command:
cat *.pf[ab] | grep UniqueID | sort | uniq -c | grep -v ' 1 '
Or if you use scripts/convert it will do that for you automatically
plus it will also give the exact list of files with duplicate UIDs.
-v size - Re-scale the font to get the size of a typical uppercase
letter somewhere around the specified size. Actually, it re-scales
the whole font to get the size of one language-dependent letter to be
at least of the specified size. Now this letter is "A" in all the
supported languages. The size is specified in the points of the
Type 1 coordinate grids, the maximal value is 1000. This is an
experimental option and should be used with caution. It tries to
increase the visible font size for a given point size and thus make
the font more readable. But if overused it may cause the fonts to
look out of scale. As of now the interesting values of size for
this option seem to be located mostly between 600 and 850. This
re-scaling may be quite useful but needs more experience to
understand the balance of its effects.
-W level - Select the verbosity level of the warnings.
Currently the levels from 0 to 4 are supported. Level 0 means no warnings
at all, level 4 means all the possible warnings. The default level is 3.
Other levels may be added in the future, so using the level number 99 is
recommended to get all the possible warnings. Going below level 2 is
not generally recommended because you may miss valuable information about
the problems with the fonts being converted.
Obsolete option:
-A - Print the font metrics (.afm file) instead of the font on STDOUT.
Use -GA instead.
Very obsolete option:
The algorithm that implemented the forced fixed width had major
flaws, so it was disabled. The code is still in the program and
some day it will be refined and returned back. Meanwhile the
option name '-f' was reused for another option. The old version was:
-f - Don't try to force the fixed width of font. Normally the converter
considers the fonts in which the glyph width deviates by not more
than 5% as buggy fixed width fonts and forces them to have really
fixed width. If this is undesirable, it can be disabled by this option.
The .pfa font format supposes that the description of the characters
is binary encoded and encrypted. This converter does not encode or
encrypt the data by default, you have to specify the option '-e'
or use the t1asm program to assemble (that means, encode and
encrypt) the font program. The t1asm program that is included with
the converter is actually a part of the t1utils package, rather old
version of which may be obtained from
http://ttf2pt1.sourceforge.net/t1utils.tar.gz
Note that t1asm from the old version of that package won't work properly
with the files generated by ttf2pt1 version 3.20 and later. Please use
t1asm packaged with ttf2pt1 or from the new version t1utils
instead. For a newer version of t1utils please look at
http://www.lcdf.org/~eddietwo/type/
So, the following command lines:
ttf2pt1 -e ttffont.ttf t1font
ttf2pt1 ttffont.ttf - | t1asm >t1font.pfa
represent two ways to get a working font. The benefit of the second form
is that other filters may be applied to the font between the converter
and assembler.
Installation and deinstallation of the converter
------------------------------------------------
The converter may be easily installed systemwide with
make install
and uninstalled with
make uninstall
By default the Makefile is configured to install in the hierarchy
of directory /usr/local. This destination directory as well as
the structure of the hierarchy may be changed by editing the Makefile.
Installation of the fonts
-------------------------
Running the converter manually becomes somewhat boring if it has to
be applied to a few hundreds of fonts and then you have to generate the
fonts.scale and/or Fontmap files. The FONTS file describes how to use
the supplied scripts to handle such cases easily. It also discusses
the installation of the fonts for a few widespread programs.
Other utilities
---------------
A few other small interesting programs that allow a cloase look at
the fonts are located in the subdirectory 'other'. They
are described shortly in others/README.
Optional packages
-----------------
Some auxiliary files are not needed by everyone and are big enough that
moving them to a separate package speeds up the downloads of the main
package significantly. As of now we have one such optional package:
ttf2pt1-chinese - contains the Chinese conversion maps
The general versioning policy for the optional packages is the following:
These packages may have no direct dependency on the ttf2pt1 version.
But they may be updated in future, as well as some versions of optional
packages may have dependencies on certain versions of ttf2pt1.
To avoid unneccessary extra releases on one hand and keep the updates in
sync with the ttf2pt1 itself on the other hand, a new version of an optional
package will be released only if there are any changes to it and it will be
given the same version number as ttf2pt1 released at the same time. So not
every release of ttf2pt1 would have a corresponding release of all optional
packages. For example, to get the correct version of optional packages for an
imaginary release 8.3.4 of ttf2pt1 you would need to look for optional
packages of the highest version not higher than (but possibly equal to) 8.3.4.
TO DO:
------
- Improve hinting.
- Improve the auto-tracing of bitmaps.
- Implement the family-level hints.
- Add generation of CID-fonts.
- Handle the composite glyphs with relative base points.
- Preserve the relative width of stems during scaling to 1000x1000 matrix.
- Add support for bitmap TTF fonts.
- Implement better support of Asian encodings.
- Implement automatic creation of ligatures.
TROUBLESHOOTING AND BUG REPORTS
-------------------------------
Have problems with conversion of some font ? The converter dumps core ? Or your
printer refuses to understand the converted fonts ? Or some characters are
missing ? Or some characters look strange ?
Send the bug reports to the ttf2pt1 development mailing list at
ttf2pt1-devel@lists.sourceforge.net.
Try to collect more information about the problem and include it into
the bug report. (Of course, even better if you would provide a ready
fix, but just a detailed bug report is also good). Provide detailed
information about your problem, this will speed up the response greatly.
Don't just write "this font looks strange after conversion" but describe
what's exactly wrong with it: for example, what characters look wrong
and what exactly is wrong about their look. Providing a link to the
original font file would be also a good idea. Try to do a little
troublehooting and report its result. This not only would help with
the fix but may also give you a temporary work-around for the bug.
First, enable full warnings with option '-W99', save them to
a file and read carefully. Sometimes the prolem is with a not implemented
feature which is reported in the warnings. Still, reporting about such
problems may be a good idea: some features were missed to cut corners,
in hope that no real font is using them. So a report about a font using
such a feature may motivate someone to implement it. Of course, you
may be the most motivated person: after all, you are the one wishing
to convert that font. ;-) Seriously, the philosophy "scrath your own itch"
seems to be the strongest moving force behind the Open Source software.
The next step is playing with the options. This serves a dual purpose:
on one hand, it helps to localize the bug, on the other hand you may be
able to get a working version of the font for the meantime while the
bug is being fixed. The typical options to try out are: first '-Ou', if
it does not help then '-Os', then '-Oh', then '-Oo'.
They are described in a bit more detail above. Try them one by one
and in combinations. See if with them the resulting fonts look better.
On some fonts ttf2pt1 just crashes. Commonly that happens because the
font being converted is highly defective (although sometimes the bug
is in ttf2pt1 itself). In any case it should not crash, so the reports
about such cases will help to handle these defects properly in future.
We try to respond to the bug reports in a timely fashion but alas, this
may not always be possible, especially if the problem is complex.
This is a volunteer project and its resources are limited. Because
of this we would appreciate bug reports as detailed as possible,
and we would appreciate the ready fixes and contributions even more.
CONTACTS
--------
ttf2pt1-announce@lists.sourceforge.net
The mailing list with announcements about ttf2pt1. It is a moderated mailing
with extremely low traffic. Everyone is encouraged to subscribe to keep in
touch with the current status of project. To subscribe use the Web interface
at http://lists.sourceforge.net/mailman/listinfo/ttf2pt1-announce.
If you have only e-mail access to the Net then send a subscribe request to
the development mailing list ttf2pt1-devel@lists.sourceforge.net and somebody
will help you with subscription.
ttf2pt1-devel@lists.sourceforge.net
ttf2pt1-users@lists.sourceforge.net
The ttf2pt1 mailing lists for development and users issues. They have not
that much traffic either. To subscribe use the Web interface at
http://lists.sourceforge.net/mailman/listinfo/ttf2pt1-devel
and http://lists.sourceforge.net/mailman/listinfo/ttf2pt1-users.
If you have only e-mail access to the Net then send a subscribe request to
the development mailing list ttf2pt1-devel@lists.sourceforge.net and somebody
will help you with subscription.
mheath@netspace.net.au
Mark Heath
A.Weeks@mcc.ac.uk
Andrew Weeks
babkin@users.sourceforge.net (preferred)
sab123@hotmail.com
http://members.bellatlantic.net/~babkin
Sergey Babkin
SEE ALSO
--------
http://ttf2pt1.sourceforge.net
The main page of the project.
http://www.netspace.net.au/~mheath/ttf2pt1/
The old main page of the project.
http://sourceforge.net/projects/gnuwin32
Precompiled binaries for Windows.
http://www.lcdf.org/~eddietwo/type/
The home page of the Type 1 utilities package.
http://www.rightbrain.com/pages/books.html
The first book about PostScript on the Web, "Thinking in PostScript".
http://fonts.apple.com/TTRefMan/index.html
The True Type reference manual.
http://partners.adobe.com/asn/developer/PDFS/TN/PLRM.pdf
Adobe PostScript reference manual.
http://partners.adobe.com/asn/developer/PDFS/TN/T1_SPEC.PDF
Specification of the Type 1 font format.
http://partners.adobe.com/asn/developer/PDFS/TN/5015.Type1_Supp.pdf
The Type 1 font format supplement.
http://partners.adobe.com/asn/developer/PDFS/TN/5004.AFM_Spec.pdf
Specification of the Adobe font metrics file format.
http://www.cs.wpi.edu/~matt/courses/cs563/talks/surface/bez_surf.html
http://www.cs.wpi.edu/~matt/courses/cs563/talks/curves.html
Information about the Bezier curves.
http://www.neuroinformatik.ruhr-uni-bochum.de/ini/PEOPLE/rmz/t1lib/t1lib.html
A stand-alone library supporting the Type1 fonts. Is neccessary
to compile the programs other/cmpf and other/dmpf.
http://www.freetype.org
A library supporting the TTF fonts. Also many useful TTF programs
are included with it.
http://heliotrope.homestead.com/files/printsoft.html
Moses Gold's collection of links to printing software.
http://linuxartist.org/fonts/
Collection of font-related links.
----------------------------------------------------------------------
----------------------------------------------------------------------
Following is the Readme of ttf2pfa (true type to type 3 font converter) It
covers other issues regarding the use of this software. Please note that
although ttf2pfa is a public domain software, ttf2pt1
is instead covered by an Open Source license. See the COPYRIGHT
file for details.
Please note also that ttf2pfa has not been maintained for a long time.
All of its functionality has been integrated into ttf2pt1 and all the
development moved to ttf2pt1, including Andrew Weeks, the author of
ttf2pfa. Ttf2pfa is provided for historical reasons only. Please use
ttf2pt1 instead.
----------------------------------------------------------------------
True Type to Postscript Font converter
--------------------------------------
My mind is still reeling from the discovery that I was able to write
this program. What it does is it reads a Microsoft TrueType font and
creates a Postscript font. '_A_ postscript font', that is, not necessarily
the same font, you understand, but a fair imitation.
Run it like this:
ttf2pfa fontfile.ttf fontname
The first parameter is the truetype filename, the second is a stem for
the output file names. The program will create a fontname.pfa containing
the Postscript font and a fontname.afm containing the metrics.
The motivation behind this is that in Linux if you do not have a
Postscript printer, but only some other printer, you can only print
Postscript by using Ghostscript. But the fonts that come with
Ghostscript are very poor (they are converted from bitmaps and look
rather lumpy). This is rather frustrating as the PC running Linux
probably has MS-Windows as well and will therefore have truetype fonts,
but which are quite useless with Linux, X or Ghostscript.
The program has been tested on over a hundred different TrueType fonts
from various sources, and seems to work fairly well. The converted
characters look OK, and the program doesn't seem to crash any more. I'm
not sure about the AFM files though, as I have no means to test them.
The fonts generated will not work with X, as the font rasterizer that
comes with X only copes with Type 1 fonts. If I have the time I may
modify ttf2pfa to generate Type 1s.
Copyright issues
----------------
I am putting this program into the public domain, so don't bother
sending me any money, I'd only have to declare it for income tax.
Copyright on fonts, however, is a difficult legal question. Any
copyright statements found in a font will be preserved in the output.
Whether you are entitled to translate them at all I don't know.
If you have a license to run a software package, like say MS-Windows, on
your PC, then you probably have a right to use any part of it, including
fonts, on that PC, even if not using that package for its intended
purpose.
I am not a lawyer, however, so this is not a legal opinion, and may be
garbage.
There shouldn't be a any problem with public domain fonts.
About the Program
-----------------
It was written in C on a IBM PC running Linux.
The TrueType format was originally developed by Apple for the MAC, which
has opposite endianness to the PC, so to ensure compatibility 16 and 32
bit fields are the wrong way round from the PC's point of view. This is
the reason for all the 'ntohs' and 'ntohl' calls. Doing it this way
means the program will also work on big-endian machines like Suns.
I doubt whether it will work on a DOS-based PC though.
The program produces what technically are Type 3 rather than Type 1
fonts. They are not compressed or encrypted and are plain text. This is
so I (and you) can see what's going on, and (if you're a Postscript guru
and really want to) can alter the outlines.
I only translate the outlines, not the 'instructions' that come with
them. This latter task is probably virtually impossible anyway. TrueType
outlines are B-splines rather than the Bezier curves that Postscript
uses. I believe that my conversion algorithm is reasonably correct, if
nothing else because the characters look right.
Problems that may occur
-----------------------
Most seriously, very complex characters (with lots of outline segments)
can make Ghostscript releases 2.x.x fail with a 'limitcheck' error. It
is possible that this may happen with some older Postscript printers as
well. Such characters will be flagged by the program and there are
basically two things you can do. First is to edit the .pfa file to
simplify or remove the offending character. This is not really
recommended. The second is to use Ghostscript release 3, if you can get
it. This has much larger limits and does not seem to have any problems
with complex characters.
Then there are buggy fonts (yes, a font can have bugs). I try to deal
with these in as sane a manner as possible, but it's not always
possible.
Encodings
---------
A postscript font must have a 256 element array, called an encoding,
each element of which is a name, which is also the name of a procedure
contained within the font. The 'BuildChar' command takes a byte and uses
it to index the encoding array to find a character name, and then looks
that up in the font's procedure table find the commands to draw the
glyph. However, not all characters need be in the encoding array. Those
that are not cannot be drawn (at least not using 'show'), however it is
possible to 're-encode' the font to enable these characters. There are
several standard encodings: Adobe's original, ISO-Latin1 and Symbol
being the most commonly encountered.
TrueType fonts are organised differently. As well as the glyph
descriptions there are a number of tables. One of these is a mapping
from a character set into the glyph array, and another is a mapping from
the glyph array into a set of Postscript character names. The problems
are:
1) Microsoft uses Unicode, a 16-bit system, to encode the font.
2) that more than one glyph is given the same Postscript name.
I deal with (1) by assuming a Latin1 encoding. The MS-Windows and
Unicode character sets are both supersets of ISO-8859-1. This usually
means that most characters will be properly encoded, but you should be
warned that some software may assume that fonts have an Adobe encoding.
Symbol, or Dingbat, fonts are in fact less of a problem, as they have
private encodings starting at 0xF000. It is easy to just lose the top
byte.
Postscript fonts can be re-encoded, either manually, or by software.
Groff, for example, generates postscript that re-encodes fonts with the
Adobe encoding. The problem here is that not all characters in the Adobe
set are in the MS-Windows set. In particular there are no fi and fl
ligatures. This means that conversions of the versions of
Times-New-Roman and Arial that come with MS-Windows cannot be used
blindly as replacements for Adobe Times-Roman and Helvetica. You can get
expanded versions of MS fonts from Microsoft's web site which do contain
these ligatures (and a lot else besides).
I deal with (2) by creating new character names. This can be error-prone
because I do not know which of them is the correct glyph to give the
name to. Some (buggy) fonts have large numbers of blank glyphs, all with
the same name.
(almost every TrueType font has three glyphs called .notdef, one of them
is usually an empty square shape, one has no outline and has zero width,
and one has no outline and a positive width. This example is not really
a problem with well formed fonts since the .notdef characters are only
used for unprintable characters, which shouldn't occur in your documents
anyway).
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