Doc/source/optional.rst

:orphan:

Optional Dependencies
=====================

The fonttools PyPI distribution also supports so-called "extras", i.e. a
set of keywords that describe a group of additional dependencies, which can be
used when installing via pip, or when specifying a requirement.
For example:

.. code:: sh

    pip install fonttools[ufo,lxml,woff,unicode]

This command will install fonttools, as well as the optional dependencies that
are required to unlock the extra features named "ufo", etc.

.. note::

    Optional dependencies are detailed by module in the list below with the ``Extra`` setting that automates ``pip`` dependency installation when this is supported.



:py:mod:`fontTools.misc.etree`
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

The module exports a ElementTree-like API for reading/writing XML files, and allows to use as the backend either the built-in ``xml.etree`` module or `lxml <https://lxml.de>`__. The latter is preferred whenever present, as it is generally faster and more secure.

*Extra:* ``lxml``


:py:mod:`fontTools.ufoLib`
^^^^^^^^^^^^^^^^^^^^^^^^^^

Package for reading and writing UFO source files; it requires:

* `fs <https://pypi.org/pypi/fs>`__: (aka ``pyfilesystem2``) filesystem abstraction layer.

* `enum34 <https://pypi.org/pypi/enum34>`__: backport for the built-in ``enum`` module (only required on Python < 3.4).

*Extra:* ``ufo``


:py:mod:`fontTools.ttLib.woff2`
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Module to compress/decompress WOFF 2.0 web fonts; it requires:

* `brotli <https://pypi.python.org/pypi/Brotli>`__: Python bindings of the Brotli compression library.

*Extra:* ``woff``


:py:mod:`fontTools.unicode`
^^^^^^^^^^^^^^^^^^^^^^^^^^^

To display the Unicode character names when dumping the ``cmap`` table
with ``ttx`` we use the ``unicodedata`` module in the Standard Library.
The version included in there varies between different Python versions.
To use the latest available data, you can install:

* `unicodedata2 <https://pypi.python.org/pypi/unicodedata2>`__: ``unicodedata`` backport for Python
  3.x updated to the latest Unicode version 14.0. Note this is not necessary if you use Python 3.11
  as the latter already comes with an up-to-date ``unicodedata``.

*Extra:* ``unicode``


:py:mod:`fontTools.varLib.interpolatable`
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

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:

* `scipy <https://pypi.python.org/pypi/scipy>`__: the Scientific Library for Python, which internally
  uses `NumPy <https://pypi.python.org/pypi/numpy>`__ arrays and hence is very fast;
* `munkres <https://pypi.python.org/pypi/munkres>`__: a pure-Python module that implements the Hungarian
  or Kuhn-Munkres algorithm.

*Extra:* ``interpolatable``


:py:mod:`fontTools.varLib.plot`
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Module for visualizing DesignSpaceDocument and resulting VariationModel.

* `matplotlib <https://pypi.org/pypi/matplotlib>`__: 2D plotting library.

*Extra:* ``plot``


:py:mod:`fontTools.misc.symfont`
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Advanced module for symbolic font statistics analysis; it requires:

* `sympy <https://pypi.python.org/pypi/sympy>`__: the Python library for symbolic mathematics.

*Extra:* ``symfont``


:py:mod:`fontTools.t1Lib`
^^^^^^^^^^^^^^^^^^^^^^^^^

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 ``MacOS``
module is no longer included in Mac Python:

* `xattr <https://pypi.python.org/pypi/xattr>`__: Python wrapper for extended filesystem attributes
  (macOS platform only).

*Extra:* ``type1``


:py:mod:`fontTools.pens.cocoaPen`
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Pen for drawing glyphs with Cocoa ``NSBezierPath``, requires:

* `PyObjC <https://pypi.python.org/pypi/pyobjc>`__: the bridge between Python and the Objective-C
  runtime (macOS platform only).


:py:mod:`fontTools.pens.qtPen`
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Pen for drawing glyphs with Qt's ``QPainterPath``, requires:

* `PyQt5 <https://pypi.python.org/pypi/PyQt5>`__: Python bindings for the Qt cross platform UI and
  application toolkit.


:py:mod:`fontTools.pens.reportLabPen`
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Pen to drawing glyphs as PNG images, requires:

* `reportlab <https://pypi.python.org/pypi/reportlab>`__: Python toolkit for generating PDFs and
  graphics.