Matplotlib PGF backend packages installed by Latex

matplotlibpackages

I want to produce an image to use in Latex. The PDF image is quite large (~200 MB), and as a solution, I wanted to use the PGF backend.

So, using the guide here, I added this line:

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

Then, Latex package installer started to run, even though Latex was not even in use. It asked me to install stringenc.sty. I checked it from ctan.org and it looked safe, so I approved it. Then, it asked me to install textglyphlist.txt, or textglyphlist.tex I can't remember exactly, but the extension was definitely neither sty nor cls.

Edit: It can also be texglyphlist.

I might be paranoid to ask it here, but is it safe? Should I expect more packages to be prompted?

Thanks in advance.

Best Answer

By passing a .pdf rather than .pgf extension matplotlib is understanding you want a PDF figure out, produced via pgf source code, rather than the pgf source directly. In order to generate a pdf from pgf source this will require a LaTeX compilation, to get the tex/pgf source out directly, use a .pgf extension.

What you describe as the LaTeX package installer sounds like MiKTeX's on-the-fly package installation, this is a normal setting for the MiKTeX distribution which produces a minimal install and then downloads and installs packages the first time the compiler meets something like a \usepackage instruction in a .tex file. These are the same packages you would have downloaded at the original installation of MiKTeX if you did a full installation instead.

Each package is only installed once (not per compilation) and so, once all the packages matplotlib needs have been installed to produce a single plot, additional packages should be a rare occurrence at best when producing significantly different plots or if matplotlib changes what it does behind the scenes.

Quick answer

Since the command that imports the png files inside the pgf image is pgfimage, I redefined it like this:

\let\pgfimageWithoutPath\pgfimage 
\renewcommand{\pgfimage}[2][]{\pgfimageWithoutPath[#1]{figures/#2}}

The first line copies the original pgfimage command to a temporary pgfimageWithoutPath. The second line redefines pgfimage to be the same as pgfimage, but prefixing the path with figures/.

Read below for more details

I actually use the chapterfolder package, which allows me to split the document into subfolders, one per chapter. It's very cool for long documents but needs a workaround for importing the figures, exactly the same problem that you had. So in the end my importing for pgfs works like this:

This is the same as above, but using chapterfolders' directives.

\let\pgfimageWithoutCF\pgfimage
\renewcommand{\pgfimage}[2][]{\pgfimageWithoutCF[#1]{\cfcurrentfolder\subfigurepath#2}}

This is a wrapper to \input{figure.pgf}, which includes the chapter path:

\newcommand{\includepgf}[1]{\input{\cfcurrentfolder\subfigurepath#1.pgf}}

And finally this is a shortcut to make the figure fit exactly the width of the text (to be used like

% usage: \resizepgf[<optional size (defaults to textwidth)>]{<filename>}
\newcommand{\resizepgf}[2][\textwidth]{
    \resizebox{#1}{!}{\includepgf{#2}}
}

Thanks to jevopi's little blog for the how-to.

[Tex/LaTex] How to incorporate and scale matplotlib plots in latex using the PGF backend

I don't think includegraphics is the natural solution since you are creating a usable LaTeX file. As @Torbjørn T. has already mentioned, you should use the input command. Then, to solve your scaling problem, you might use

\scalebox{1.5}{\input{sample.pgf}}

for example; there is no preliminary LaTeX compilation involved.

In case you want to use includegraphics, it is natural to save your image as a png file in python.
Looking at the output of the python code, the pgf file, it seems to me that there are some cropping issues.

The code

\documentclass{article}
\usepackage{tikz}
\usepackage{tikzscale}
\usepackage{pgfplots}

\usepackage{lipsum}
\begin{document}
\lipsum[1]

\begin{figure}[htb!]
  \centering
  \scalebox{.5}{\input{sample.pgf}}
  \scalebox{1}{\input{sample.pgf}}
  \scalebox{1.5}{\input{sample.pgf}}
  \caption{Sample figure modified with scalebox}
  \label{fig:1}
\end{figure}

\lipsum[2]
\end{document}

Best Answer

Related Solutions

[Tex/LaTex] Matplotlib PGF images in subdirectory

Quick answer

Read below for more details

[Tex/LaTex] How to incorporate and scale matplotlib plots in latex using the PGF backend

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