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Typesetting With XeLaTeX/LuaLaTeX

How to typeset text with the pgf backend in Matplotlib.

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 either switching to the backend

  1. matplotlib.use('pgf')

or registering it for handling pdf output

  1. from matplotlib.backends.backend_pgf import FigureCanvasPgf
  2. matplotlib.backend_bases.register_backend('pdf', FigureCanvasPgf)

The second method allows you to keep using regular interactive backends and to save xelatex, lualatex or pdflatex compiled PDF files from the graphical user interface.

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 PATH.

Rc parameters 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”

::: tip Note

TeX defines a set of special characters, such as:

  1. # $ % & ~ _ ^ \ { }

Generally, these characters must be escaped correctly. For convenience, some characters (_,^,%) are automatically escaped outside of math environments.

:::

Multi-Page PDF Files

The pgf backend also supports multipage pdf files using PdfPages

  1. from matplotlib.backends.backend_pgf import PdfPages
  2. import matplotlib.pyplot as plt
  4. with PdfPages('multipage.pdf', metadata={'author': 'Me'}) as pdf:
  6.     fig1, ax1 = plt.subplots()
  7.     ax1.plot([1, 5, 3])
  8.     pdf.savefig(fig1)
  10.     fig2, ax2 = plt.subplots()
  11.     ax2.plot([1, 5, 3])
  12.     pdf.savefig(fig2)

Font specification

The fonts used for obtaining the size of text elements or when compiling figures to PDF are usually defined in the matplotlib rc parameters. You can also use the LaTeX default Computer Modern fonts by clearing the lists for font.serif, font.sans-serif or 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.

When saving to .pgf, the font configuration matplotlib used for the layout of the figure is included in the header of the text file.

  1. """
  2. =========
  3. Pgf Fonts
  4. =========
  6. """
  8. import matplotlib.pyplot as plt
  9. plt.rcParams.update({
  10.     "font.family": "serif",
  11.     "font.serif": [],                    # use latex default serif font
  12.     "font.sans-serif": ["DejaVu Sans"],  # use a specific sans-serif font
  13. })
  15. plt.figure(figsize=(4.5, 2.5))
  16. plt.plot(range(5))
  17. plt.text(0.5, 3., "serif")
  18. plt.text(0.5, 2., "monospace", family="monospace")
  19. plt.text(2.5, 2., "sans-serif", family="sans-serif")
  20. plt.text(2.5, 1., "comic sans", family="Comic Sans MS")
  21. plt.xlabel("µ is not $\\mu$")
  22. plt.tight_layout(.5)

Custom preamble

Full customization is possible by adding your own commands to the preamble. Use the pgf.preamble parameter 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 pgf.rcfonts.

  1. """
  2. ============
  3. Pgf Preamble
  4. ============
  6. """
  8. import matplotlib as mpl
  9. mpl.use("pgf")
  10. import matplotlib.pyplot as plt
  11. plt.rcParams.update({
  12.     "font.family": "serif",  # use serif/main font for text elements
  13.     "text.usetex": True,     # use inline math for ticks
  14.     "pgf.rcfonts": False,    # don't setup fonts from rc parameters
  15.     "pgf.preamble": [
  16.          "\\usepackage{units}",          # load additional packages
  17.          "\\usepackage{metalogo}",
  18.          "\\usepackage{unicode-math}",   # unicode math setup
  19.          r"\setmathfont{xits-math.otf}",
  20.          r"\setmainfont{DejaVu Serif}",  # serif font via preamble
  21.          ]
  22. })
  24. plt.figure(figsize=(4.5, 2.5))
  25. plt.plot(range(5))
  26. plt.xlabel("unicode text: я, ψ, €, ü, \\unitfrac[10]{°}{µm}")
  27. plt.ylabel("\\XeLaTeX")
  28. plt.legend(["unicode math: $λ=∑_i^∞ μ_i^2$"])
  29. plt.tight_layout(.5)

Choosing the TeX system

The TeX system to be used by matplotlib is chosen by the pgf.texsystem parameter. 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.

  1. """
  2. =============
  3. Pgf Texsystem
  4. =============
  6. """
  8. import matplotlib.pyplot as plt
  9. plt.rcParams.update({
  10.     "pgf.texsystem": "pdflatex",
  11.     "pgf.preamble": [
  12.          r"\usepackage[utf8x]{inputenc}",
  13.          r"\usepackage[T1]{fontenc}",
  14.          r"\usepackage{cmbright}",
  15.          ]
  16. })
  18. plt.figure(figsize=(4.5, 2.5))
  19. plt.plot(range(5))
  20. plt.text(0.5, 3., "serif", family="serif")
  21. plt.text(0.5, 2., "monospace", family="monospace")
  22. plt.text(2.5, 2., "sans-serif", family="sans-serif")
  23. plt.xlabel(r"µ is not $\mu$")
  24. plt.tight_layout(.5)

Troubleshooting

  • Please note that the TeX packages found in some Linux distributions and MiKTeX installations are dramatically outdated. Make sure to update your package catalog and upgrade or install a recent TeX distribution.
  • On Windows, the PATH environment variable may need to be modified to include the directories containing the latex, dvipng and ghostscript executables. See Environment Variables and Setting environment variables in windows for details.
  • A limitation on Windows causes the backend to keep file handles that have been opened by your application open. As a result, it may not be possible to delete the corresponding files until the application closes (see #1324).
  • 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.
  • The pgf.preamble rc setting 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. XeTeX, 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.
  • 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. Another way would be to “rasterize” parts of the graph causing problems using either the rasterized=True keyword, or .set_rasterized(True) as per this example.
  • If you still need help, please see Getting help

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