r"""

.. redirect-from:: /tutorials/text/pgf

.. _pgf:

************************************************************

Text rendering with XeLaTeX/LuaLaTeX via the ``pgf`` backend

************************************************************

Using the ``pgf`` backend, Matplotlib can export figures as pgf drawing

commands that can be processed with pdflatex, xelatex or lualatex. XeLaTeX and

LuaLaTeX have full Unicode support and can use any font that is installed in

the operating system, making use of advanced typographic features of OpenType,

AAT and Graphite. Pgf pictures created by ``plt.savefig('figure.pgf')``

can be embedded as raw commands in LaTeX documents. Figures can also be

directly compiled and saved to PDF with ``plt.savefig('figure.pdf')`` by

switching the backend ::

matplotlib.use('pgf')

or by explicitly requesting the use of the ``pgf`` backend ::

plt.savefig('figure.pdf', backend='pgf')

or by registering it for handling pdf output ::

from matplotlib.backends.backend_pgf import FigureCanvasPgf

matplotlib.backend_bases.register_backend('pdf', FigureCanvasPgf)

The last method allows you to keep using regular interactive backends and to

save xelatex, lualatex or pdflatex compiled PDF files from the graphical user

interface. Note that, in that case, the interactive display will still use the

standard interactive backends (e.g., QtAgg), and in particular use latex to

compile relevant text snippets.

Matplotlib's pgf support requires a recent LaTeX_ installation that includes

the TikZ/PGF packages (such as TeXLive_), preferably with XeLaTeX or LuaLaTeX

installed. If either pdftocairo or ghostscript is present on your system,

figures can optionally be saved to PNG images as well. The executables

for all applications must be located on your :envvar:`PATH`.

`.rcParams` that control the behavior of the pgf backend:

================= =====================================================

Parameter Documentation

================= =====================================================

pgf.preamble Lines to be included in the LaTeX preamble

pgf.rcfonts Setup fonts from rc params using the fontspec package

pgf.texsystem Either "xelatex" (default), "lualatex" or "pdflatex"

================= =====================================================

.. note::

TeX defines a set of special characters, such as::

# $ % & ~ _ ^ \ { }

Generally, these characters must be escaped correctly. For convenience,

some characters (_, ^, %) are automatically escaped outside of math

environments. Other characters are not escaped as they are commonly needed

in actual TeX expressions. However, one can configure TeX to treat them as

"normal" characters (known as "catcode 12" to TeX) via a custom preamble,

such as::

plt.rcParams["pgf.preamble"] = (

r"\AtBeginDocument{\catcode`\&=12\catcode`\#=12}")

.. _pgf-rcfonts:

Multi-Page PDF Files

====================

The pgf backend also supports multipage pdf files using

`~.backend_pgf.PdfPages`

.. code-block:: python

from matplotlib.backends.backend_pgf import PdfPages

import matplotlib.pyplot as plt

with PdfPages('multipage.pdf', metadata={'author': 'Me'}) as pdf:

fig1, ax1 = plt.subplots()

ax1.plot([1, 5, 3])

pdf.savefig(fig1)

fig2, ax2 = plt.subplots()

ax2.plot([1, 5, 3])

pdf.savefig(fig2)

.. redirect-from:: /gallery/userdemo/pgf_fonts

Font specification

==================

The fonts used for obtaining the size of text elements or when compiling

figures to PDF are usually defined in the `.rcParams`. You can also use the

LaTeX default Computer Modern fonts by clearing the lists for :rc:`font.serif`,

:rc:`font.sans-serif` or :rc:`font.monospace`. Please note that the glyph

coverage of these fonts is very limited. If you want to keep the Computer

Modern font face but require extended Unicode support, consider installing the

`Computer Modern Unicode`__ fonts *CMU Serif*, *CMU Sans Serif*, etc.

__ https://sourceforge.net/projects/cm-unicode/

When saving to ``.pgf``, the font configuration Matplotlib used for the

layout of the figure is included in the header of the text file.

.. code-block:: python

import matplotlib.pyplot as plt

plt.rcParams.update({

"font.family": "serif",

# Use LaTeX default serif font.

"font.serif": [],

# Use specific cursive fonts.

"font.cursive": ["Comic Neue", "Comic Sans MS"],

})

fig, ax = plt.subplots(figsize=(4.5, 2.5))

ax.plot(range(5))

ax.text(0.5, 3., "serif")

ax.text(0.5, 2., "monospace", family="monospace")

ax.text(2.5, 2., "sans-serif", family="DejaVu Sans") # Use specific sans font.

ax.text(2.5, 1., "comic", family="cursive")

ax.set_xlabel("µ is not $\\mu$")

.. redirect-from:: /gallery/userdemo/pgf_preamble_sgskip

.. _pgf-preamble:

Custom preamble

===============

Full customization is possible by adding your own commands to the preamble.

Use :rc:`pgf.preamble` if you want to configure the math fonts,

using ``unicode-math`` for example, or for loading additional packages. Also,

if you want to do the font configuration yourself instead of using the fonts

specified in the rc parameters, make sure to disable :rc:`pgf.rcfonts`.

.. code-block:: python

import matplotlib as mpl

mpl.use("pgf")

import matplotlib.pyplot as plt

plt.rcParams.update({

"font.family": "serif", # use serif/main font for text elements

"text.usetex": True, # use inline math for ticks

"pgf.rcfonts": False, # don't setup fonts from rc parameters

"pgf.preamble": "\n".join([

r"\usepackage{url}", # load additional packages

r"\usepackage{unicode-math}", # unicode math setup

r"\setmainfont{DejaVu Serif}", # serif font via preamble

])

})

fig, ax = plt.subplots(figsize=(4.5, 2.5))

ax.plot(range(5))

ax.set_xlabel("unicode text: я, ψ, €, ü")

ax.set_ylabel(r"\url{https://matplotlib.org}")

ax.legend(["unicode math: $λ=∑_i^∞ μ_i^2$"])

.. redirect-from:: /gallery/userdemo/pgf_texsystem

.. _pgf-texsystem:

Choosing the TeX system

=======================

The TeX system to be used by Matplotlib is chosen by :rc:`pgf.texsystem`.

Possible values are ``'xelatex'`` (default), ``'lualatex'`` and ``'pdflatex'``.

Please note that when selecting pdflatex, the fonts and Unicode handling must

be configured in the preamble.

.. code-block:: python

import matplotlib.pyplot as plt

plt.rcParams.update({

"pgf.texsystem": "pdflatex",

"pgf.preamble": "\n".join([

r"\usepackage[utf8x]{inputenc}",

r"\usepackage[T1]{fontenc}",

r"\usepackage{cmbright}",

]),

})

fig, ax = plt.subplots(figsize=(4.5, 2.5))

ax.plot(range(5))

ax.text(0.5, 3., "serif", family="serif")

ax.text(0.5, 2., "monospace", family="monospace")

ax.text(2.5, 2., "sans-serif", family="sans-serif")

ax.set_xlabel(r"µ is not $\mu$")

.. _pgf-troubleshooting:

Troubleshooting

===============

* Make sure LaTeX is working and on your :envvar:`PATH` (for raster output,

pdftocairo or ghostscript is also required). The :envvar:`PATH` environment

variable may need to be modified (in particular on Windows) to include the

directories containing the executable. See :ref:`environment-variables` and

:ref:`setting-windows-environment-variables` for details.

* Sometimes the font rendering in figures that are saved to png images is

very bad. This happens when the pdftocairo tool is not available and

ghostscript is used for the pdf to png conversion.

* Make sure what you are trying to do is possible in a LaTeX document,

that your LaTeX syntax is valid and that you are using raw strings

if necessary to avoid unintended escape sequences.

* :rc:`pgf.preamble` provides lots of flexibility, and lots of

ways to cause problems. When experiencing problems, try to minimalize or

disable the custom preamble.

* Configuring an ``unicode-math`` environment can be a bit tricky. The

TeXLive distribution for example provides a set of math fonts which are

usually not installed system-wide. XeLaTeX, unlike LuaLaTeX, cannot find

these fonts by their name, which is why you might have to specify

``\setmathfont{xits-math.otf}`` instead of ``\setmathfont{XITS Math}`` or

alternatively make the fonts available to your OS. See this

`tex.stackexchange.com question`__ for more details.

__ https://tex.stackexchange.com/q/43642/

* If the font configuration used by Matplotlib differs from the font setting

in yout LaTeX document, the alignment of text elements in imported figures

may be off. Check the header of your ``.pgf`` file if you are unsure about

the fonts Matplotlib used for the layout.

* Vector images and hence ``.pgf`` files can become bloated if there are a lot

of objects in the graph. This can be the case for image processing or very

big scatter graphs. In an extreme case this can cause TeX to run out of

memory: "TeX capacity exceeded, sorry" You can configure latex to increase

the amount of memory available to generate the ``.pdf`` image as discussed on

`tex.stackexchange.com <https://tex.stackexchange.com/q/7953/>`_.

Another way would be to "rasterize" parts of the graph causing problems

using either the ``rasterized=True`` keyword, or ``.set_rasterized(True)`` as

per :doc:`this example </gallery/misc/rasterization_demo>`.

* Various math fonts are compiled and rendered only if corresponding font

packages are loaded. Specifically, when using ``\mathbf{}`` on Greek letters,

the default computer modern font may not contain them, in which case the

letter is not rendered. In such scenarios, the ``lmodern`` package should be

loaded.

* If you still need help, please see :ref:`reporting-problems`

.. _LaTeX: http://www.tug.org

.. _TeXLive: http://www.tug.org/texlive/

"""