testbed/matplotlib__matplotlib/doc/devel/dependencies.rst

.. _dependencies:

============
Dependencies
============

Runtime dependencies
====================


Mandatory dependencies
----------------------

When installing through a package manager like ``pip`` or ``conda``, the
mandatory dependencies are automatically installed. This list is mainly for
reference.

* `Python <https://www.python.org/downloads/>`_ (>= 3.9)
* `contourpy <https://pypi.org/project/contourpy/>`_ (>= 1.0.1)
* `cycler <https://matplotlib.org/cycler/>`_ (>= 0.10.0)
* `dateutil <https://pypi.org/project/python-dateutil/>`_ (>= 2.7)
* `fontTools <https://fonttools.readthedocs.io/en/latest/>`_ (>= 4.22.0)
* `kiwisolver <https://github.com/nucleic/kiwi>`_ (>= 1.3.1)
* `NumPy <https://numpy.org>`_ (>= 1.21)
* `packaging <https://pypi.org/project/packaging/>`_ (>= 20.0)
* `Pillow <https://pillow.readthedocs.io/en/latest/>`_ (>= 8.0)
* `pyparsing <https://pypi.org/project/pyparsing/>`_ (>= 2.3.1)
* `importlib-resources <https://pypi.org/project/importlib-resources/>`_
  (>= 3.2.0; only required on Python < 3.10)


.. _optional_dependencies:

Optional dependencies
---------------------

The following packages and tools are not required but extend the capabilities
of Matplotlib.

Backends
~~~~~~~~

Matplotlib figures can be rendered to various user interfaces. See
:ref:`what-is-a-backend` for more details on the optional Matplotlib backends
and the capabilities they provide.

* Tk_ (>= 8.5, != 8.6.0 or 8.6.1): for the Tk-based backends. Tk is part of
  most standard Python installations, but it's not part of Python itself and
  thus may not be present in rare cases.
* PyQt6_ (>= 6.1), PySide6_, PyQt5_, or PySide2_: for the Qt-based backends.
* PyGObject_ and pycairo_ (>= 1.14.0): for the GTK-based backends. If using pip
  (but not conda or system package manager) PyGObject must be built from
  source; see `pygobject documentation
  <https://pygobject.readthedocs.io/en/latest/devguide/dev_environ.html>`_.
* pycairo_ (>= 1.14.0) or cairocffi_ (>= 0.8): for cairo-based backends.
* wxPython_ (>= 4): for the wx-based backends.  If using pip (but not conda or
  system package manager) on Linux wxPython wheels must be manually downloaded
  from https://wxpython.org/pages/downloads/.
* Tornado_ (>= 5): for the WebAgg backend.
* ipykernel_: for the nbagg backend.
* macOS (>= 10.12): for the macosx backend.

.. _Tk: https://docs.python.org/3/library/tk.html
.. _PyQt5: https://pypi.org/project/PyQt5/
.. _PySide2: https://pypi.org/project/PySide2/
.. _PyQt6: https://pypi.org/project/PyQt6/
.. _PySide6: https://pypi.org/project/PySide6/
.. _PyGObject: https://pygobject.readthedocs.io/en/latest/
.. _wxPython: https://www.wxpython.org/
.. _pycairo: https://pycairo.readthedocs.io/en/latest/
.. _cairocffi: https://cairocffi.readthedocs.io/en/latest/
.. _Tornado: https://pypi.org/project/tornado/
.. _ipykernel: https://pypi.org/project/ipykernel/

Animations
~~~~~~~~~~

* `ffmpeg <https://www.ffmpeg.org/>`_: for saving movies.
* `ImageMagick <https://www.imagemagick.org/script/index.php>`_: for saving
  animated gifs.

Font handling and rendering
~~~~~~~~~~~~~~~~~~~~~~~~~~~

* `LaTeX <https://www.latex-project.org/>`_ (with `cm-super
  <https://ctan.org/pkg/cm-super>`__ and `underscore
  <https://ctan.org/pkg/underscore>`__) and `GhostScript (>= 9.0)
  <https://ghostscript.com/releases/>`_: for rendering text with LaTeX.
* `fontconfig <https://www.fontconfig.org>`_ (>= 2.7): for detection of system
  fonts on Linux.

C libraries
-----------

Matplotlib brings its own copies of the following libraries:

- ``Agg``: the Anti-Grain Geometry C++ rendering engine
- ``ttconv``: a TrueType font utility

Additionally, Matplotlib depends on:

- FreeType_ (>= 2.3): a font rendering library
- QHull_ (>= 2020.2): a library for computing triangulations

.. _FreeType: https://www.freetype.org/
.. _Qhull: http://www.qhull.org/

By default, Matplotlib downloads and builds its own copies of FreeType (this is
necessary to run the test suite, because different versions of FreeType
rasterize characters differently) and of Qhull.  As an exception, Matplotlib
defaults to the system version of FreeType on AIX.

Use system libraries
~~~~~~~~~~~~~~~~~~~~

To force Matplotlib to use a copy of FreeType or Qhull already installed in
your system, create a :file:`mplsetup.cfg` file with the following contents:

.. code-block:: cfg

   [libs]
   system_freetype = true
   system_qhull = true

before running

.. code-block:: sh

   python -m pip install .


You can also use the :envvar:`MPLSETUPCFG` to specify the path to a cfg file when
installing from pypi.


In this case, you need to install the FreeType and Qhull library and headers.
This can be achieved using a package manager, e.g. for FreeType:

.. code-block:: sh

   # Pick ONE of the following:
   sudo apt install libfreetype6-dev  # Debian/Ubuntu
   sudo dnf install freetype-devel    # Fedora
   brew install freetype              # macOS with Homebrew
   conda install freetype             # conda, any OS

(adapt accordingly for Qhull).

On Linux and macOS, it is also recommended to install pkg-config_, a helper
tool for locating FreeType:

.. code-block:: sh

   # Pick ONE of the following:
   sudo apt install pkg-config  # Debian/Ubuntu
   sudo dnf install pkgconf     # Fedora
   brew install pkg-config      # macOS with Homebrew
   conda install pkg-config     # conda
   # Or point the PKG_CONFIG environment variable to the path to pkg-config:
   export PKG_CONFIG=...

.. _pkg-config: https://www.freedesktop.org/wiki/Software/pkg-config/

If not using pkg-config (in particular on Windows), you may need to set the
include path (to the library headers) and link path (to the libraries)
explicitly, if they are not in standard locations.  This can be done using
standard environment variables -- on Linux and OSX:

.. code-block:: sh

   export CFLAGS='-I/directory/containing/ft2build.h'
   export LDFLAGS='-L/directory/containing/libfreetype.so'

and on Windows:

.. code-block:: bat

   set CL=/IC:\directory\containing\ft2build.h
   set LINK=/LIBPATH:C:\directory\containing\freetype.lib

If you go this route but need to reset and rebuild to change your settings,
remember to clear your artifacts before re-building::

  git clean -xfd


Manual Download
~~~~~~~~~~~~~~~


If the automatic download does not work (for example on air-gapped systems) it
is preferable to instead use system libraries.  However you can manually
download and unpack the tarballs into::

  build/freetype-2.6.1  # on all platforms but windows ARM64
  build/freetype-2.11.1 # on windows ARM64
  build/qhull-2020.2

at the top level of the checkout repository.  The expected sha256 hashes of
the downloaded tarballs is in :file:`setupext.py` if you wish to verify
before unpacking.


Minimum pip / manylinux support (linux)
---------------------------------------

Matplotlib publishes `manylinux wheels <https://github.com/pypa/manylinux>`_
which have a minimum version of pip which will recognize the wheels

- Python 3.9+: ``manylinx2014`` / pip >= 19.3

In all cases the required version of pip is embedded in the CPython source.



.. _development-dependencies:

Dependencies for building Matplotlib
====================================

.. _setup-dependencies:

Setup dependencies
------------------

- `certifi <https://pypi.org/project/certifi/>`_ (>= 2020.06.20).  Used while
  downloading the freetype and QHull source during build.  This is not a
  runtime dependency.
- `PyBind11 <https://pypi.org/project/pybind11/>`_ (>= 2.6). Used to connect C/C++ code
  with Python.
- `setuptools <https://pypi.org/project/setuptools/>`_ (>= 42).
- `setuptools_scm <https://pypi.org/project/setuptools-scm/>`_ (>= 7).  Used to
  update the reported ``mpl.__version__`` based on the current git commit.
  Also a runtime dependency for editable installs.
- `NumPy <https://numpy.org>`_ (>= 1.21).  Also a runtime dependency.


.. _compile-dependencies:

C++ compiler
------------

Matplotlib requires a C++ compiler that supports C++11.

- `gcc 4.8.1 <https://gcc.gnu.org/projects/cxx-status.html#cxx11>`_ or higher.  For gcc <6.5 you will
  need to set ``$CFLAGS=-std=c++11`` to enable C++11 support.
  `Installing GCC: Binaries <https://gcc.gnu.org/install/binaries.html>`_.
- `clang 3.3 <https://clang.llvm.org/cxx_status.html>`_ or higher.
  `LLVM Download Page <https://releases.llvm.org/download.html>`_.
- `Visual Studio 2015
  <https://docs.microsoft.com/en-us/cpp/overview/visual-cpp-language-conformance?view=msvc-140>`_
  (aka VS 14.0) or higher. A free version of Build Tools for Visual Studio is available for
  `download <https://visualstudio.microsoft.com/downloads/?q=build+tools>`_.


.. _test-dependencies:

Dependencies for testing Matplotlib
===================================
This section lists the additional software required for
:ref:`running the tests <testing>`.

Required:

- pytest_ (>= 7.0.0)

Optional:

In addition to all of the optional dependencies on the main library, for
testing the following will be used if they are installed.

- Ghostscript_ (>= 9.0, to render PDF files)
- Inkscape_ (to render SVG files)
- nbformat_ and nbconvert_ used to test the notebook backend
- pandas_ used to test compatibility with Pandas
- pikepdf_ used in some tests for the pgf and pdf backends
- psutil_ used in testing the interactive backends
- pytest-cov_ (>= 2.3.1) to collect coverage information
- pytest-flake8_ to test coding standards using flake8_
- pytest-timeout_ to limit runtime in case of stuck tests
- pytest-xdist_ to run tests in parallel
- pytest-xvfb_ to run tests without windows popping up (Linux)
- pytz_ used to test pytz int
- sphinx_ used to test our sphinx extensions
- WenQuanYi Zen Hei and `Noto Sans CJK <https://fonts.google.com/noto/use>`_
  fonts for testing font fallback and non-western fonts
- xarray_ used to test compatibility with xarray

If any of these dependencies are not discovered the tests that rely on them
will be skipped by pytest.

.. note::

  When installing Inkscape on Windows, make sure that you select “Add
  Inkscape to system PATH”, either for all users or current user, or the
  tests will not find it.

.. _Ghostscript: https://ghostscript.com/
.. _Inkscape: https://inkscape.org
.. _flake8: https://pypi.org/project/flake8/
.. _nbconvert: https://pypi.org/project/nbconvert/
.. _nbformat: https://pypi.org/project/nbformat/
.. _pandas: https://pypi.org/project/pandas/
.. _pikepdf: https://pypi.org/project/pikepdf/
.. _psutil: https://pypi.org/project/psutil/
.. _pytz: https://fonts.google.com/noto/use#faq
.. _pytest-cov: https://pytest-cov.readthedocs.io/en/latest/
.. _pytest-flake8: https://pypi.org/project/pytest-flake8/
.. _pytest-timeout: https://pypi.org/project/pytest-timeout/
.. _pytest-xdist: https://pypi.org/project/pytest-xdist/
.. _pytest-xvfb: https://pypi.org/project/pytest-xvfb/
.. _pytest: http://doc.pytest.org/en/latest/
.. _sphinx: https://pypi.org/project/Sphinx/
.. _xarray: https://pypi.org/project/xarray/


.. _doc-dependencies:

Dependencies for building Matplotlib's documentation
====================================================

Python packages
---------------
The additional Python packages required to build the
:ref:`documentation <documenting-matplotlib>` are listed in
:file:`doc-requirements.txt` and can be installed using ::

    pip install -r requirements/doc/doc-requirements.txt

The content of :file:`doc-requirements.txt` is also shown below:

.. include:: ../../requirements/doc/doc-requirements.txt
   :literal:

Additional external dependencies
--------------------------------
Required:

* a minimal working LaTeX distribution, e.g., `TeX Live <https://www.tug.org/texlive/>`_ or
  `MikTeX <https://miktex.org/>`_
* `Graphviz <http://www.graphviz.org/download>`_
* the following LaTeX packages (if your OS bundles TeX Live, the
  "complete" version of the installer, e.g. "texlive-full" or "texlive-all",
  will often automatically include these packages):

  * `cm-super <https://ctan.org/pkg/cm-super>`_
  * `dvipng <https://ctan.org/pkg/dvipng>`_
  * `underscore <https://ctan.org/pkg/underscore>`_

Optional, but recommended:

* `Inkscape <https://inkscape.org>`_
* `optipng <http://optipng.sourceforge.net>`_
* the font "Humor Sans" (aka the "XKCD" font), or the free alternative
  `Comic Neue <http://comicneue.com/>`_
* the font "Times New Roman"

.. note::

  The documentation will not build without LaTeX and Graphviz.  These are not
  Python packages and must be installed separately. The documentation can be
  built without Inkscape and optipng, but the build process will raise various
  warnings. If the build process warns that you are missing fonts, make sure
  your LaTeX distribution bundles cm-super or install it separately.