Figure number filter for pandoc


Keywords
pandoc, figure, numbers, filter
License
GPL-2.0+
Install
pip install pandoc-fignos==1.3.0

Documentation

New in 2.4.0: Updated for pandoc 2.11.

more...

pandoc-fignos 2.4.0

pandoc-fignos is a pandoc filter for numbering figures and their references when converting from markdown to other formats. It is part of the pandoc-xnos filter suite. LaTeX/pdf, html, and epub output have native support. Native support for docx output is a work in progress.

Demonstration: Processing demo3.md with pandoc + pandoc-fignos gives numbered figures and references in pdf, tex, html, epub, docx and other formats.

This version of pandoc-fignos was tested using pandoc 1.15.2 - 2.11.1.1,1 and may be used with linux, macOS, and Windows. Bug reports and feature requests may be posted on the project's Issues tracker. If you find pandoc-fignos useful, then please kindly give it a star on GitHub.

See also: pandoc-eqnos, pandoc-tablenos, pandoc-secnos
Other filters: pandoc-comments, pandoc-latex-extensions

Contents

  1. Installation
  2. Usage
  3. Markdown Syntax
  4. Customization
  5. Technical Details
  6. Getting Help
  7. Development
  8. What's New

Installation

Pandoc-fignos requires python. It is easily installed -- see here.2 Either python 2.7 or 3.x will do.

Pandoc-fignos may be installed using the shell command

pip install pandoc-fignos --user

and upgraded by appending --upgrade to the above command. Pip is a program that downloads and installs software from the Python Package Index, PyPI. It normally comes installed with a python distribution.3

Instructions for installing from source are given in DEVELOPERS.md.

Usage

Pandoc-fignos is activated by using the

--filter pandoc-fignos

option with pandoc. Alternatively, use

--filter pandoc-xnos

to activate all of the filters in the pandoc-xnos suite (if installed).

Any use of --filter pandoc-citeproc or --bibliography=FILE should come after the pandoc-fignos or pandoc-xnos filter calls.

Markdown Syntax

The cross-referencing syntax used by pandoc-fignos was developed in pandoc Issue #813 -- see this post by @scaramouche1.

To mark a figure for numbering, add an identifier to its attributes:

![Caption.](image.png){#fig:id}

The prefix #fig: is required. id should be replaced with a unique string composed of letters, numbers, dashes and underscores. If id is omitted then the figure will be numbered but unreferenceable. Alternatively, reference link attributes may be used.

To reference the figure, use

@fig:id

or

{@fig:id}

Curly braces protect a reference and are stripped from the output.

Demonstration: Processing demo.md with pandoc + pandoc-fignos gives numbered figures and references in pdf, tex, html, epub, docx and other formats.

Clever References

Writing markdown like

See fig. @fig:id.

seems a bit redundant. Pandoc-fignos supports "clever references" via single-character modifiers in front of a reference. Users may write

 See +@fig:id.

to have the reference name (i.e., "fig.") automatically generated. The above form is used mid-sentence; at the beginning of a sentence, use

 *@fig:id

instead. If clever references are enabled by default (see Customization, below), then users may disable it for a given reference using4

!@fig:id

Demonstration: Processing demo2.md with pandoc + pandoc-fignos gives numbered figures and references in pdf, tex, html, epub, docx and other formats.

Note: When using *@fig:id and emphasis (e.g., *italics*) in the same sentence, the * in the clever reference must be backslash-escaped; i.e., \*@fig:id.

Tagged Figures

The figure number may be overridden by placing a tag in the figure's attributes block:

![Caption.](image.png){#fig:id tag="B.1"}

The tag may be arbitrary text, or an inline equation such as $\text{B.1}'$. Mixtures of the two are not currently supported.

Disabling Links

To disable a link on a reference, set nolink=True in the reference's attributes:

@fig:id{nolink=True}

Subfigures

Pandoc does not provide syntactical support for subfigures. However, subfigures of arbitrary complexity may be assembled using the native capabilities of each output format, and referenced using pandoc-fignos.

LaTeX/pdf subfigures may be coded and referenced as shown in demo4.md. Processing with pandoc + pandoc-fignos gives demo4.pdf. This technique uses capabilities provided by the subcaption package. "Bad reference" warnings involving subfigures may be ignored when using this approach.

Html/epub subfigures may be coded and referenced as shown in demo5.md. Processing with pandoc + pandoc-fignos gives demo5.html. This technique uses pandoc's fenced divs. Fenced divs may be nested and styled as required with css. Note that pandoc requires figures to be in their own paragraph (i.e., with a blank line above and below).

The above demos use certain customizations, described next.

Customization

Pandoc-fignos may be customized by setting variables in the metadata block or on the command line (using -M KEY=VAL). The following variables are supported:

  • fignos-warning-level or xnos-warning-level - Set to 0 for no warnings, 1 for critical warnings, or 2 (default) for all warnings. Warning level 2 should be used when troubleshooting.

  • fignos-cleveref or xnos-cleveref - Set to True to assume "+" clever references by default;

  • xnos-capitalise - Capitalises the names of "+" clever references (e.g., change from "fig." to "Fig.");

  • fignos-plus-name - Sets the name of a "+" clever reference (e.g., change it from "fig." to "figure"). Settings here take precedence over xnos-capitalise;

  • fignos-star-name - Sets the name of a "*" clever reference (e.g., change it from "Figure" to "Fig.");

  • fignos-caption-name - Sets the name at the beginning of a caption (e.g., change it from "Figure to "Fig." or "图");

  • fignos-caption-separator or xnos-caption-separator - Sets the caption separator (e.g., the colon in "Figure 1:") to something else. It must be one of none, colon, period, space, quad, or newline; and

  • fignos-number-by-section or xnos-number-by-section - Set to True to number figures by section (e.g., Fig. 1.1, 1.2, etc in Section 1, and Fig 2.1, 2.2, etc in Section 2). For LaTeX/pdf, html, and epub output, this feature should be used together with pandoc's --number-sections option enabled. For docx, use docx custom styles instead.

    This option should not be set for numbering by chapter in LaTeX/pdf book document classes.

  • xnos-number-offset - Set to an integer to offset the section numbers when numbering figures by section. For html and epub output, this feature should be used together with pandoc's --number-offset option set to the same integer value. For LaTeX/pdf, this option offsets the actual section numbers as required.

Note that variables beginning with fignos- apply to only pandoc-fignos, whereas variables beginning with xnos- apply to all of the pandoc-fignos/eqnos/tablenos/secnos filters.

Demonstration: Processing demo3.md with pandoc + pandoc-fignos gives numbered figures and references in pdf, tex, html, epub, docx and other formats.

Technical Details

LaTeX/pdf Output

During processing, pandoc-fignos inserts packages and supporting LaTeX into the header-includes metadata field. To see what is inserted, set the fignos-warning-level meta variable to 2. Note that any use of pandoc's --include-in-header option overrides all header-includes.

An example reference in LaTeX looks like

See \cref{fig:1}.

An example figure looks like

\begin{figure}
  \hypertarget{fig:1}{%
    \centering
    \includegraphics[width=1in,height=\textheight]{img/fig-1.png}
    \caption{The number one.}\label{fig:1}
  }
\end{figure}

Other details:

  • The cleveref and caption packages are used for clever references and caption control, respectively;
  • The \label and \ref macros are used for figure labels and references, respectively (\Cref and \cref are used for clever references);
  • Clever reference names are set with \Crefname and \crefname;
  • The caption name is set with\figurename;
  • Tags are supported by way of a custom environment that temporarily redefines \thefigure; and
  • Caption prefixes (e.g., "Figure 1:") are disabled for unnumbered figures by way of a custom environment that uses \captionsetup.

Html/Epub Output

An example reference in html looks like

See fig. <a href="#fig:1">1</a>.

An example figure looks like

<div id="fig:1" class="fignos">
  <figure>
    <img src="img/fig-1.png" style="width:1in" alt="" />
    <figcaption>
      <span>Figure 1:</span> The number one.
    </figcaption>
  </figure>
</div>

The figure and its caption are wrapped in a <div></div> with an id for linking and with class fignos to allow for css styling.

Docx Output

Docx OOXML output is under development and subject to change. Native capabilities will be used wherever possible.

Getting Help

If you have any difficulties with pandoc-fignos, or would like to see a new feature, then please submit a report to our Issues tracker.

Development

Pandoc-fignos will continue to support pandoc 1.15-onward and python 2 & 3 for the foreseeable future. The reasons for this are that a) some users cannot upgrade pandoc and/or python; and b) supporting all versions tends to make pandoc-fignos more robust.

Developer notes are maintained in DEVELOPERS.md.

What's New

New in 2.4.0: Updated for pandoc 2.11.

New in 2.3.1: Updated for pandoc 2.10.1.

New in 2.2.0: Html/epub subfigures support.

New in 2.1.2: LaTeX subfigures support. Documentation is provided to show how to reference LaTeX subfigures. No changes to existing code were required.

New in 2.1.1: Warnings for duplicate reference targets.

New in 2.0.0: This version represents a major revision of pandoc-fignos. While the interface is similar to that of the 1.x series, some users may encounter minor compatibility issues.

Warning messages are a new feature of pandoc-fignos. The meta variable fignos-warning-level may be set to 0, 1, or 2 depending on the degree of warnings desired. Warning level 1 will alert users to bad references, malformed attributes, and unknown meta variables. Warning level 2 (the default) adds informational messages that should be helpful with debugging. Level 0 turns all messages off.

Meta variable names have been updated. Deprecated names have been removed, and new variables have been added. Note in particular that the fignos-number-sections and xnos-number-sections variables have been renamed to fignos-number-by-section and xnos-number-by-section, respectively.

The basic filter and library codes have been refactored and improved with a view toward maintainability. While extensive tests have been performed, some problems may have slipped through unnoticed. Bug reports should be submitted to our Issues tracker.

LaTeX/PDF:

LaTeX codes produced by pandoc-fignos are massively improved. The hacks used before were causing some users problems. The new approach provides more flexibility and better compatibility with the LaTeX system.

Supporting LaTeX is now written to the header-includes meta data. Users no longer need to include LaTeX commands in the header-includes to get basic pandoc-fignos functions to work. Use fignos-warning-level: 2 to see what pandoc-fignos adds to the header-includes.

A word of warning: Pandoc-fignos's additions to the header-includes are overridden when pandoc's --include-in-header option is used. This is owing to a design choice in pandoc. Users may choose to deliberately override pandoc-fignos's header-includes by providing their own LaTeX through --include-in-header. If a user needs to include other bits of LaTeX in this way, then they will need to do the same for the LaTeX that pandoc-fignos needs.

Finally, the \label tags are now installed where pandoc chooses, which is currently outside the \caption field. Pandoc-fignos previously forced the \label to go inside \caption.

Html/Epub:

The figure is now enclosed in a <div> which contains the id and class fignos. This change was made to facilitate styling. The id was formerly contained in an anchor tag.

Epub support is generally improved.


Footnotes

1: Pandoc 2.4 broke how references are parsed, and so is not supported.

2: For MacOS, my preferred install method is to use the package available from python.org.

3: Anaconda users may be tempted to use conda instead. This is not advised. The packages distributed on the Anaconda cloud are unofficial, are not posted by me, and in some cases are ancient. Some tips on using pip in a conda environment may be found here.

4: The disabling modifier "!" is used instead of "-" because pandoc drops minus signs in front of references.