TITLE: Using the LaTeX 'float' package with Pandoc
DATE: 2019-01-29
AUTHOR: John L. Godlee
====================================================================


When I convert markdown documents to pdf files using LaTeX and
Pandoc, LaTeX is very helpful at placing images optimally to
minimise whitespace. a basic pandoc command might look like this:

   pandoc -f markdown -t latex  -o output.pdf input.md

The issue is, when I'm using pandoc with markdown, I often don't
care about the placement of images. I'm normally making short
documents for note-taking or something like that. As a result, I
normally place images in the text in the place I want them to
appear in the pdf output.

After a bit of googling for inspiration, I found two methods of
doing this. The first, is very simple and tells pandoc not to
create figures, but instead just to include images inline.

   pandoc -f markdown-implicit_figures -t pdf -o output.pdf
input.md

This is fine, but it removes centering on the images, and removes
the option for me to include a caption with ![CAPTION
HERE](img/diagram.png).

A better option I think, is to allow LaTeX to use the float package
in order to place images using attributes such as [H] to force
images to appear where they appear in the source.

I already have a LaTeX template that I use for pandoc, called
simple_doc.latex. It lives in ~/.pandoc/templates/ so it can be
linked to easily in pandoc commands.

The relevant piece of simple_doc.latex is:

   $if(graphics)$
   \usepackage{graphics}
   \usepackage{graphicx}
   \usepackage{float}
   \makeatletter

   % Define max width and max height arguments to be conditional
on img size

\def\maxwidth{\ifdim\Gin@nat@width>\linewidth\linewidth\else\Gin@nat
@width\fi}

\def\maxheight{\ifdim\Gin@nat@height>\textheight\textheight\else\Gin
@nat@height\fi}
   \makeatother

   % Scale images if necessary, so that they will not overflow the
page
   % margins by default, and it is still possible to overwrite the
defaults
   % using explicit options in \includegraphics[width, height,
..]{}

\setkeys{Gin}{width=0.5\maxwidth,height=0.5\maxheight,keepaspectrati
o}

   \let\origfigure\figure
   \let\endorigfigure\endfigure
   \renewenvironment{figure}[1][2] {
       \expandafter\origfigure\expandafter[H]
   } {
       \endorigfigure
   }

   $endif$

I got the inspiration for this from this Stack Overflow question.

 [Stack Overflow question]:
https://tex.stackexchange.com/questions/101725/latex-figures-appear-
before-text-in-pandoc-markdown