filters.lua

local system = require "pandoc.system"

local tikz_doc_templates = {
  tikzcd = {
    [[
\documentclass[tikz]{standalone}
\usepackage{amsmath,amssymb}
\usetikzlibrary{decorations.markings}
\tikzset{mid vert/.style={/utils/exec=\tikzset{every node/.append style={outer sep=0.8ex}},
    postaction=decorate,decoration={markings,
      mark=at position 0.5 with {\draw[-] (0,#1) -- (0,-#1);}}},
  mid vert/.default=0.75ex}
\usetikzlibrary{cd}
\usetikzlibrary{calc}
% `pathmorphing` is necessary to draw squiggly arrows.
\usetikzlibrary{decorations.pathmorphing}

% A TikZ style for curved arrows of a fixed height, due to AndréC.
\tikzset{curve/.style={settings={#1},to path={(\tikztostart)
    .. controls ($(\tikztostart)!\pv{pos}!(\tikztotarget)!\pv{height}!270:(\tikztotarget)$)
    and ($(\tikztostart)!1-\pv{pos}!(\tikztotarget)!\pv{height}!270:(\tikztotarget)$)
    .. (\tikztotarget)\tikztonodes}},
    settings/.code={\tikzset{quiver/.cd,#1}
        \def\pv##1{\pgfkeysvalueof{/tikz/quiver/##1}}},
    quiver/.cd,pos/.initial=0.35,height/.initial=0}

% TikZ arrowhead/tail styles.
\tikzset{tail reversed/.code={\pgfsetarrowsstart{tikzcd to}}}
\tikzset{2tail/.code={\pgfsetarrowsstart{Implies[reversed]}}}
\tikzset{2tail reversed/.code={\pgfsetarrowsstart{Implies}}}
% TikZ arrow styles.
\tikzset{no body/.style={/tikz/dash pattern=on 0 off 1mm}}
\begin{document}
\begin{tikzpicture}
\node[scale=2] (OWEKW6Ur) {
\begin{tikzcd}
]],
    [[
\end{tikzcd}
};
\end{tikzpicture}
\end{document}
  ]],
  },
  tikz = {
    [[
\documentclass[tikz]{standalone}
\usetikzlibrary{graphs, graphdrawing}
\usegdlibrary{trees}
\begin{document}
\begin{tikzpicture}
\node[scale=2] (OWEKW6Ur) {
]],
    [[
};
\end{tikzpicture}
\end{document}
  ]],
  },
  tikzit = {
    [[
\documentclass[tikz]{standalone}
\usepackage{amsmath}
% Official TikZiT style file: https://tikzit.github.io/tikzit.sty

\usetikzlibrary{backgrounds}
\usetikzlibrary{arrows}
\usetikzlibrary{shapes,shapes.geometric,shapes.misc}

% this style is applied by default to any tikzpicture included via \tikzfig
\tikzstyle{tikzfig}=[baseline=-0.25em,scale=0.5]

% these are dummy properties used by TikZiT, but ignored by LaTex
\pgfkeys{/tikz/tikzit fill/.initial=0}
\pgfkeys{/tikz/tikzit draw/.initial=0}
\pgfkeys{/tikz/tikzit shape/.initial=0}
\pgfkeys{/tikz/tikzit category/.initial=0}

% standard layers used in .tikz files
\pgfdeclarelayer{edgelayer}
\pgfdeclarelayer{nodelayer}
\pgfsetlayers{background,edgelayer,nodelayer,main}

% style for blank nodes
\tikzstyle{none}=[inner sep=0mm]

% include a .tikz file
\newcommand{\tikzfig}[1]{%
{\tikzstyle{every picture}=[tikzfig]
\IfFileExists{#1.tikz}
  {\input{#1.tikz}}
  {%
    \IfFileExists{./figures/#1.tikz}
      {\input{./figures/#1.tikz}}
      {\tikz[baseline=-0.5em]{\node[draw=red,font=\color{red},fill=red!10!white] {\textit{#1}};}}%
  }}%
}

% the same as \tikzfig, but in a {center} environment
\newcommand{\ctikzfig}[1]{%
\begin{center}\rm
  \tikzfig{#1}
\end{center}}

% fix strange self-loops, which are PGF/TikZ default
\tikzstyle{every loop}=[]

% TiKZ style file generated by TikZiT. You may edit this file manually,
% but some things (e.g. comments) may be overwritten. To be readable in
% TikZiT, the only non-comment lines must be of the form:
% \tikzstyle{NAME}=[PROPERTY LIST]

% Node styles
\tikzstyle{variable_node}=[fill={rgb,255: red,108; green,154; blue,195}, draw=black, shape=circle, text=white]
\tikzstyle{block}=[fill={rgb,255: red,226; green,143; blue,65}, draw=black, shape=rectangle, text=white]
\tikzstyle{Ob}=[fill=none, draw=none, shape=rectangle]
\tikzstyle{table}=[fill={rgb,255: red,224; green,229; blue,205}, draw={rgb,255: red,95; green,96; blue,98}, shape=rectangle, rounded corners]
\tikzstyle{title}=[fill=white, draw={rgb,255: red,128; green,190; blue,99}, shape=rectangle, text=black, line width=1mm, minimum width=8cm, minimum height=1cm]
\tikzstyle{blockprime}=[fill={rgb,255: red,108; green,154; blue,195}, draw=black, shape=rectangle, text=white]
\tikzstyle{Hom3by3}=[fill=white, draw=black, shape=rectangle, minimum height=20mm]
\tikzstyle{finsetdot}=[fill=black, draw=black, shape=circle]
\tikzstyle{Hom1x3}=[fill=white, draw=black, shape=rectangle]
\tikzstyle{new edge style 1}=[line width=0.6mm]
\tikzstyle{Hom1x3_rounded}=[fill=white, draw=black, shape=rectangle, rounded corners]
\tikzstyle{outerbox6x17}=[fill=none, draw=black, shape=rectangle, minimum height=6cm, minimum width=17cm, rounded corners]
\tikzstyle{outerbox}=[fill=none, draw=black, shape=rectangle, rounded corners, minimum height=4cm, minimum width=6cm]
\tikzstyle{add}=[fill=white, draw=black, shape=circle]
\tikzstyle{rel_dagger}=[fill=white, draw=black, shape=trapezium, rounded corners, shape border rotate=90, minimum width=1.5cm]
\tikzstyle{rel}=[fill=white, draw=black, shape=trapezium, rounded corners, shape border rotate=270, minimum width=1.5cm]
\tikzstyle{mhom3x1}=[fill=white, draw=black, shape=rectangle, rounded corners, minimum height=10mm]

% Edge styles
\tikzstyle{new edge style 0}=[->, draw={rgb,255: red,127; green,129; blue,131}, line width=0.6mm]
\tikzstyle{arrow}=[draw={rgb,255: red,177; green,179; blue,182}, ->, line width=0.4mm]
\tikzstyle{undirected}=[-, draw={rgb,255: red,177; green,179; blue,182}, line width=0.6mm]
\tikzstyle{cospan_edge}=[->, draw=black, dashed, line width=0.4mm]
\tikzstyle{undirected edge}=[-, line width=0.6mm, draw={rgb,255: red,177; green,179; blue,182}]
\tikzstyle{blueline}=[-, draw={rgb,255: red,108; green,154; blue,195}, line width=0.7mm]
\tikzstyle{functor}=[->, draw=black, line width=1.2mm]

\begin{document}
\begin{tikzpicture}
]],
    [[
\end{tikzpicture}
\end{document}
  ]],
  },
}

function trim(s) return (s:gsub("^%s*(.-)%s*$", "%1")) end

local function tikz2image(src, template, outfile)
  system.with_temporary_directory("tikz2image", function(tmpdir)
    system.with_working_directory(tmpdir, function()
      local f = io.open("tikz.tex", "w")
      f:write(template[1] .. trim(src) .. template[2])
      f:close()
      os.execute "lualatex tikz.tex"
      os.execute "pdf2svg tikz.pdf tikz.svg"
      os.execute("mv tikz.svg " .. outfile)
    end)
  end)
end

local function graphviz2image(src, outfile)
  system.with_temporary_directory("graphviz2image", function(tmpdir)
    system.with_working_directory(tmpdir, function()
      local f = io.open("graphviz.dot", "w")
      f:write(trim(src))
      f:close()
      os.execute "dot -Tsvg graphviz.dot -o graphviz.svg"
      os.execute("mv graphviz.svg " .. outfile)
    end)
  end)
end

local function file_exists(name)
  local f = io.open(name, "r")
  if f ~= nil then
    io.close(f)
    return true
  else
    return false
  end
end

function CodeBlock(el)
  if el.classes[1] == "graphviz" then
    local fbasename = "graphviz_build_" .. pandoc.sha1(el.text) .. ".svg"
    local fname = system.get_working_directory() .. "/" .. fbasename
    if not file_exists(fname) then graphviz2image(el.text, fname) end
    return pandoc.Div(pandoc.Image({}, fbasename), { class = "graphvizz" })
  elseif tikz_doc_templates[el.classes[1]] ~= nil then
    local fbasename = "tikz_build_" .. pandoc.sha1(el.text) .. ".svg"
    local fname = system.get_working_directory() .. "/" .. fbasename
    if not file_exists(fname) then tikz2image(el.text, tikz_doc_templates[el.classes[1]], fname) end
    return pandoc.Div(pandoc.Image({}, fbasename), { class = "tikzcd" })
  else
    return el
  end
end