.. highlight:: rest
Math support in Sphinx
======================
.. module:: sphinx.ext.mathbase
:synopsis: Common math support for pngmath and mathjax / jsmath.
.. versionadded:: 0.5
Since mathematical notation isn't natively supported by HTML in any way, Sphinx
supports math in documentation with several extensions.
The basic math support is contained in :mod:`sphinx.ext.mathbase`. Other math
support extensions should, if possible, reuse that support too.
.. note::
:mod:`.mathbase` is not meant to be added to the :confval:`extensions` config
value, instead, use either :mod:`sphinx.ext.pngmath` or
:mod:`sphinx.ext.mathjax` as described below.
The input language for mathematics is LaTeX markup. This is the de-facto
standard for plain-text math notation and has the added advantage that no
further translation is necessary when building LaTeX output.
Keep in mind that when you put math markup in **Python docstrings** read by
:mod:`autodoc `, you either have to double all backslashes,
or use Python raw strings (``r"raw"``).
:mod:`.mathbase` defines these new markup elements:
.. rst:role:: math
Role for inline math. Use like this::
Since Pythagoras, we know that :math:`a^2 + b^2 = c^2`.
.. rst:directive:: math
Directive for displayed math (math that takes the whole line for itself).
The directive supports multiple equations, which should be separated by a
blank line::
.. math::
(a + b)^2 = a^2 + 2ab + b^2
(a - b)^2 = a^2 - 2ab + b^2
In addition, each single equation is set within a ``split`` environment,
which means that you can have multiple aligned lines in an equation,
aligned at ``&`` and separated by ``\\``::
.. math::
(a + b)^2 &= (a + b)(a + b) \\
&= a^2 + 2ab + b^2
For more details, look into the documentation of the `AmSMath LaTeX
package`_.
When the math is only one line of text, it can also be given as a directive
argument::
.. math:: (a + b)^2 = a^2 + 2ab + b^2
Normally, equations are not numbered. If you want your equation to get a
number, use the ``label`` option. When given, it selects an internal label
for the equation, by which it can be cross-referenced, and causes an equation
number to be issued. See :rst:role:`eqref` for an example. The numbering
style depends on the output format.
There is also an option ``nowrap`` that prevents any wrapping of the given
math in a math environment. When you give this option, you must make sure
yourself that the math is properly set up. For example::
.. math::
:nowrap:
\begin{eqnarray}
y & = & ax^2 + bx + c \\
f(x) & = & x^2 + 2xy + y^2
\end{eqnarray}
.. rst:role:: eq
Role for cross-referencing equations via their label. This currently works
only within the same document. Example::
.. math:: e^{i\pi} + 1 = 0
:label: euler
Euler's identity, equation :eq:`euler`, was elected one of the most
beautiful mathematical formulas.
:mod:`sphinx.ext.pngmath` -- Render math as PNG images
------------------------------------------------------
.. module:: sphinx.ext.pngmath
:synopsis: Render math as PNG images.
This extension renders math via LaTeX and dvipng_ into PNG images. This of
course means that the computer where the docs are built must have both programs
available.
There are various config values you can set to influence how the images are
built:
.. confval:: pngmath_latex
The command name with which to invoke LaTeX. The default is ``'latex'``; you
may need to set this to a full path if ``latex`` is not in the executable
search path.
Since this setting is not portable from system to system, it is normally not
useful to set it in ``conf.py``; rather, giving it on the
:program:`sphinx-build` command line via the :option:`-D` option should be
preferable, like this::
sphinx-build -b html -D pngmath_latex=C:\tex\latex.exe . _build/html
.. versionchanged:: 0.5.1
This value should only contain the path to the latex executable, not
further arguments; use :confval:`pngmath_latex_args` for that purpose.
.. confval:: pngmath_dvipng
The command name with which to invoke ``dvipng``. The default is
``'dvipng'``; you may need to set this to a full path if ``dvipng`` is not in
the executable search path.
.. confval:: pngmath_latex_args
Additional arguments to give to latex, as a list. The default is an empty
list.
.. versionadded:: 0.5.1
.. confval:: pngmath_latex_preamble
Additional LaTeX code to put into the preamble of the short LaTeX files that
are used to translate the math snippets. This is empty by default. Use it
e.g. to add more packages whose commands you want to use in the math.
.. confval:: pngmath_dvipng_args
Additional arguments to give to dvipng, as a list. The default value is
``['-gamma 1.5', '-D 110']`` which makes the image a bit darker and larger
then it is by default.
An arguments you might want to add here is e.g. ``'-bg Transparent'``,
which produces PNGs with a transparent background. This is not enabled by
default because some Internet Explorer versions don't like transparent PNGs.
.. note::
When you "add" an argument, you need to reproduce the default arguments if
you want to keep them; that is, like this::
pngmath_dvipng_args = ['-gamma 1.5', '-D 110', '-bg Transparent']
.. confval:: pngmath_use_preview
``dvipng`` has the ability to determine the "depth" of the rendered text: for
example, when typesetting a fraction inline, the baseline of surrounding text
should not be flush with the bottom of the image, rather the image should
extend a bit below the baseline. This is what TeX calls "depth". When this
is enabled, the images put into the HTML document will get a
``vertical-align`` style that correctly aligns the baselines.
Unfortunately, this only works when the `preview-latex package`_ is
installed. Therefore, the default for this option is ``False``.
.. confval:: pngmath_add_tooltips
Default: true. If false, do not add the LaTeX code as an "alt" attribute for
math images.
.. versionadded:: 1.1
:mod:`sphinx.ext.mathjax` -- Render math via JavaScript
-------------------------------------------------------
.. module:: sphinx.ext.mathjax
:synopsis: Render math using JavaScript via MathJax.
.. versionadded:: 1.1
This extension puts math as-is into the HTML files. The JavaScript package
MathJax_ is then loaded and transforms the LaTeX markup to readable math live in
the browser.
Because MathJax (and the necessary fonts) is very large, it is not included in
Sphinx.
.. confval:: mathjax_path
The path to the JavaScript file to include in the HTML files in order to load
MathJax.
The default is the ``http://`` URL that loads the JS files from the `MathJax
CDN `_. If you want MathJax to
be available offline, you have to donwload it and set this value to a
different path.
The path can be absolute or relative; if it is relative, it is relative to
the ``_static`` directory of the built docs.
For example, if you put MathJax into the static path of the Sphinx docs, this
value would be ``MathJax/MathJax.js``. If you host more than one Sphinx
documentation set on one server, it is advisable to install MathJax in a
shared location.
You can also give a full ``http://`` URL different from the CDN URL.
:mod:`sphinx.ext.jsmath` -- Render math via JavaScript
------------------------------------------------------
.. module:: sphinx.ext.jsmath
:synopsis: Render math using JavaScript via JSMath.
This extension works just as the MathJax extension does, but uses the older
package jsMath_. It provides this config value:
.. confval:: jsmath_path
The path to the JavaScript file to include in the HTML files in order to load
JSMath. There is no default.
The path can be absolute or relative; if it is relative, it is relative to
the ``_static`` directory of the built docs.
For example, if you put JSMath into the static path of the Sphinx docs, this
value would be ``jsMath/easy/load.js``. If you host more than one
Sphinx documentation set on one server, it is advisable to install jsMath in
a shared location.
.. _dvipng: http://savannah.nongnu.org/projects/dvipng/
.. _MathJax: http://www.mathjax.org/
.. _jsMath: http://www.math.union.edu/~dpvc/jsmath/
.. _preview-latex package: http://www.gnu.org/software/auctex/preview-latex.html
.. _AmSMath LaTeX package: http://www.ams.org/publications/authors/tex/amslatex