What is this?
FontTools requires Python 2.7, 3.4 or later.
The package is listed in the Python Package Index (PyPI), so you can install it with pip:
pip install fonttools
If you would like to contribute to its development, you can clone the repository from GitHub, install the package in 'editable' mode and modify the source code in place. We recommend creating a virtual environment, using virtualenv or Python 3 venv module.
# download the source code to 'fonttools' folder git clone https://github.com/fonttools/fonttools.git cd fonttools # create new virtual environment called e.g. 'fonttools-venv', or anything you like python -m virtualenv fonttools-venv # source the `activate` shell script to enter the environment (Un*x); to exit, just type `deactivate` . fonttools-venv/bin/activate # to activate the virtual environment in Windows `cmd.exe`, do fonttools-venv\Scripts\activate.bat # install in 'editable' mode pip install -e .
TTX – From OpenType and TrueType to XML and Back
Once installed you can use the
ttx command to convert binary font
.ttf, etc) to the TTX XML format, edit them, and
convert them back to binary format. TTX files have a .ttx file
ttx /path/to/font.otf ttx /path/to/font.ttx
The TTX application can be used in two ways, depending on what platform you run it on:
- As a command line tool (Windows/DOS, Unix, macOS)
- By dropping files onto the application (Windows, macOS)
TTX detects what kind of files it is fed: it will output a
when it sees a
.otf, and it will compile a
.otf when the input file is a
.ttx file. By default, the output
file is created in the same folder as the input file, and will have the
same name as the input file but with a different extension. TTX will
never overwrite existing files, but if necessary will append a unique
number to the output filename (before the extension) such as
When using TTX from the command line there are a bunch of extra options.
These are explained in the help text, as displayed when typing
ttx -h at the command prompt. These additional options include:
- specifying the folder where the output files are created
- specifying which tables to dump or which tables to exclude
- merging partial
.ttxfiles with existing
- listing brief table info instead of dumping to
- splitting tables to separate
- disabling TrueType instruction disassembly
The TTX file format
The following tables are currently supported:
BASE, CBDT, CBLC, CFF, CFF2, COLR, CPAL, DSIG, EBDT, EBLC, FFTM, Feat, GDEF, GMAP, GPKG, GPOS, GSUB, Glat, Gloc, HVAR, JSTF, LTSH, MATH, META, MVAR, OS/2, SING, STAT, SVG, Silf, Sill, TSI0, TSI1, TSI2, TSI3, TSI5, TSIB, TSID, TSIJ, TSIP, TSIS, TSIV, TTFA, VDMX, VORG, VVAR, ankr, avar, bsln, cidg, cmap, cvar, cvt, feat, fpgm, fvar, gasp, gcid, glyf, gvar, hdmx, head, hhea, hmtx, kern, lcar, loca, ltag, maxp, meta, mort, morx, name, opbd, post, prep, prop, sbix, trak, vhea and vmtx
Other tables are dumped as hexadecimal data.
TrueType fonts use glyph indices (GlyphIDs) 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 glyph names are either extracted from the
CFF table or the
post table, or are derived from a Unicode
cmap table. In the
latter case the Adobe Glyph List is used to calculate names based on
Unicode values. If all of these methods fail, names are invented based
on GlyphID (eg
It is possible that different glyphs use the same name. If this happens,
we force the names to be unique by appending
#n to the name (
being an integer number.) The original names are being kept, so this has
no influence on a "round tripped" font.
Because the order in which glyphs are stored inside the binary font is important, we maintain an ordered list of glyph names in the font.
Commands for inspecting, merging and subsetting fonts are also available:
pyftinspect pyftmerge pyftsubset
fontTools Python Module
The fontTools Python module provides a convenient way to programmatically edit font files.
>>> from fontTools.ttLib import TTFont >>> font = TTFont('/path/to/font.ttf') >>> font <fontTools.ttLib.TTFont object at 0x10c34ed50> >>>
A selection of sample Python programs is in the Snippets directory.
fontTools package currently has no (required) external dependencies
besides the modules included in the Python Standard Library.
However, a few extra dependencies are required by some of its modules, which
are needed to unlock optional features.
Module to compress/decompress WOFF 2.0 web fonts; it requires:
- brotli: Python bindings of the Brotli compression library.
To better compress WOFF 1.0 web fonts, the following module can be used instead of the built-in
- zopfli: Python bindings of the Zopfli compression library.
To display the Unicode character names when dumping the
ttxwe use the
unicodedatamodule in the Standard Library. The version included in there varies between different Python versions. To use the latest available data, you can install:
unicodedatabackport for Python 2.7 and 3.5 updated to the latest Unicode version 9.0. Note this is not necessary if you use Python 3.6 as the latter already comes with an up-to-date
Module for finding wrong contour/component order between different masters. It requires one of the following packages in order to solve the so-called "minimum weight perfect matching problem in bipartite graphs", or the Assignment problem:
Advanced module for symbolic font statistics analysis; it requires:
- sympy: the Python library for symbolic mathematics.
To get the file creator and type of Macintosh PostScript Type 1 fonts on Python 3 you need to install the following module, as the old
MacOSmodule is no longer included in Mac Python:
- xattr: Python wrapper for extended filesystem attributes (macOS platform only).
Pen for drawing glyphs with Cocoa
- PyObjC: the bridge between Python and the Objective-C runtime (macOS platform only).
Pen for drawing glyphs with Qt's
- PyQt5: Python bindings for the Qt cross platform UI and application toolkit.
Pen to drawing glyphs as PNG images, requires:
- reportlab: Python toolkit for generating PDFs and graphics.
A GUI font inspector, requires one of the following packages:
To run the test suite, you can do:
python setup.py test
If you have pytest, you can run
pytest command directly. The tests will run against the
fontTools package, or the first one found in the
You can also use tox to automatically run tests on different Python versions in isolated virtual environments.
pip install tox tox
Note that when you run
tox without arguments, the tests are executed
for all the environments listed in tox.ini's
envlist. In our case,
this includes Python 2.7 and 3.6, so for this to work the
python3.6 executables must be available in your
You can specify an alternative environment list via the
TOXENV environment variable:
tox -e py27-nocov TOXENV="py36-cov,htmlcov" tox
TTX/FontTools development is ongoing in an active community of developers, that includes professional developers employed at major software corporations and type foundries as well as hobbyists.
Feature requests and bug reports are always welcome at https://github.com/fonttools/fonttools/issues/
The best place for discussions about TTX from an end-user perspective as well as TTX/FontTools development is the https://groups.google.com/d/forum/fonttools mailing list. There is also a development https://groups.google.com/d/forum/fonttools-dev mailing list for continuous integration notifications. You can also email Behdad privately at firstname.lastname@example.org
The fontTools project was started by Just van Rossum in 1999, and was maintained as an open source project at http://sourceforge.net/projects/fonttools/. In 2008, Paul Wise (pabs3) began helping Just with stability maintenance. In 2013 Behdad Esfahbod began a friendly fork, thoroughly reviewing the codebase and making changes at https://github.com/behdad/fonttools to add new features and support for new font formats.
In alphabetical order:
Olivier Berten, Samyak Bhuta, Erik van Blokland, Petr van Blokland, Jelle Bosma, Sascha Brawer, Tom Byrer, Frédéric Coiffier, Vincent Connare, Dave Crossland, Simon Daniels, Behdad Esfahbod, Behnam Esfahbod, Hannes Famira, Sam Fishman, Matt Fontaine, Yannis Haralambous, Greg Hitchcock, Jeremie Hornus, Khaled Hosny, John Hudson, Denis Moyogo Jacquerye, Jack Jansen, Tom Kacvinsky, Jens Kutilek, Antoine Leca, Werner Lemberg, Tal Leming, Peter Lofting, Cosimo Lupo, Masaya Nakamura, Dave Opstad, Laurence Penney, Roozbeh Pournader, Garret Rieger, Read Roberts, Guido van Rossum, Just van Rossum, Andreas Seidel, Georg Seifert, Miguel Sousa, Adam Twardoch, Adrien Tétar, Vitaly Volkov, Paul Wise.
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