XML based format (called TTX) and back.



FontTools is a suite of tools and libraries for manipulating fonts. It is written in Python and has a BSD-style, open-source licence -- see LICENSE.txt. It's hosted at sourceforge.net.

It currently reads and writes TrueType font files, reads PostScript Type 1 fonts and more. It contains two command line programs to convert TrueType fonts to an


FontTools' functionality is aimed towards font developers and font tool developers. It can of course be used to just access fonts (outlines, metrics, etc.) but it is not optimized for that. It will be further developed so it can be the core of any font editor. And that's exactly what it will be for our upcoming major rewrite of RoboFog, our (commercial) PythonPowered font editor for MacOS.


You need the following software to use FontTools:
  • Python. The fresh versions as well as older versions (You need 1.5.1 or higher) can be obtained here: http://www.python.org/download/ or here: http://sourceforge.net/projects/python/

    Windows: grab the Windows installer, run the full install.
    Un*x: follow the build instructions.
    Linux: maybe you already *have* Python: check whether you have version 1.5.1 or newer.
    MacOS: grab the installer, run "Easy Install"

  • The Numeric Python extension (you don't need this under MacOS, since it's included in the MacPython installer). Get a fresh version from the download page, linked from here: http://sourceforge.net/projects/numpy/

    Windows: grab the "Numeric-*.exe" archive, it's an installer. Make sure the Python version in the archive name (eg. "2.1") matches the Python version you have.
    Linux/Un*x: get a source archive and run this command from the unpacked directory:
    python ./setup.py install

  • PyXML, a set of XML tools:
    Installation should be very similar to installing Numeric Python, see above.
Now run the "setup.py" script from the FontTools archive. This will install all the modules in the right places, as well as tries to compile the one (optional) C extension contained in FontTools. (XXX: need precompiled Mac and Windows binaries, *or* a way to skip compilation when there's no compiler available.)

Additional Mac instructions: De-binhex "TTX.rsrc.hqx" by dropping it onto StuffIt expander. (Or use your own preferred method) The "TTX.py" script included in this archive is the Mac-only main program: Drop it onto the "BuildApplet" app inside the Python folder; this will produce the TTX applet.

User documentation

For MacOS there's a small application called TTX. If you drop a TrueType file onto it, it will convert it to XML. If you drop an XML file onto it, it will convert it back to TrueType. Please read the additional README file in the Mac subdirectory, since it behaves quite differently than the command line programs described below.

For Unix and DOS I've provided two command line programs:

  • ttDump.py
  • ttCompile.py
They do pretty much what you'd expect. They take several arguments: an input file name and optionally an output file name. There are some extra options which are explained by the 'usage' text; use the -h option to display it.

Adam Twardoch contributed a Windows registry script (ttx_shellext_win32.py) which makes the two above tools available under the Right Mouse Button. I haven't tested these myself, but I'm very interested in hearing about the results!

Note about glyph names and TrueType GlyphID's

TrueType fonts use glyph indices (GlyphID's) to refer to glyphs in most places. While this is fine in binary form, it is really hard to work with for humans. Therefore we use names instead.

The names are derived from what is found in the 'post' table. It is possible that different glyphs use the same PS name. If this happens, we force the names to be unique by appending "#n" to the name (n being an integer number). The original PS names will still be maintained by the 'post' table, so even though we use a different name internally, we are still able to write the 'post' table back in original form. If there is no proper 'post' table available, names will be derived from a Unicode cmap (if available) in conjuction with the Adobe Glyph List (see fontTools/agl.py).

Because the order in which glyphs are stored inside the TT font is important, ttLib maintains an ordered list of glyph names in the font.


Please join the fonttools-discussion mailing list at SourceForge. Subscription info can be found if you follow the "Mailing Lists" link at the SourceForge project page. You can also email me directly at just@letterror.com.

If you want to follow the development of FontTools closely, or would like to contribute, you can also subscribe to the fonttools-checkins mailing list.

Anonymous CVS-access

The FontTools sources are also accessible through CVS, see the the SourceForge project page. Let me know if you'd like to become a co-developer.

Developer documentation

Sorry, documentation beyond doc strings in the source code is still on my to-do list... Below follows a brief overview of what's there.

GUI Tools

TTX -- A simple Mac app that converts TrueType (or OpenType) fonts to TTX format and back.

Command line tools

  • ttDump.py -- dumps a TrueType (or OpenType) font file to TTX format.
  • ttCompile.py -- compiles a TTX file back into a TTF (or OTF) file.

The library

  • fontTools.t1Lib -- Provides a Type 1 font reader. Writing is a planned feature.
  • fontTools.ttLib -- Extensive TrueType tools. Reads and writes. This is the flagship of FontTools, it's by far the most mature component. Contains a completely modular TTF table converter architecture. See ttLib/tables/table_API_readme.txt.
  • fontTools.afmLib -- And AFM file reader/writer.
  • fontTools.cffLib -- Reads CFF fonts. Writing is a planned feature.
  • fontTools.unicode -- A simple (but large) module that translates Unicode values to their descriptive names. Still Unicode 2.0.
  • fontTools.agl -- Interface to the Adobe Glyph List: maps unicode values to glyph names and back.
  • fontTools.fondLib -- A reader/writer class for Mac FOND resources.
  • fontTools.nfntLib -- Reads Mac NFNT bitmap font resources.


(in alphabetical order) Erik van Blokland, Petr van Blokland, Jelle Bosma, Vincent Connare, Simon Daniels, Hannes Famira, Greg Hitchcock, Jack Jansen, Antoine Leca, Werner Lemberg, Peter Lofting, Dave Opstad, Laurence Penney, Guido van Rossum, Adam Twardoch.


FontTools/TTX -- 1999-2001 Just van Rossum; Letterror (just@letterror.com)