Generate a list of figure sources from figure captions containing \source{}

Question

This question stems from the same book project described in Generate a list of figure numbers and filenames from \includegraphics. The answers there provide the basic code to generate a text file of figure numbers and associated file names from LaTeX source. Now, I need to extend this method to a further task of collecting a text file of figure sources.

In this book (nearly) all figure \caption{}s have included in them a source{} command giving the figure source. It is presently defined just to print information about the figure source as text, with Source: in italics

\newcommand{\source}[1]{\emph{Source:} #1.}

Some figures require permissions, others don't, but for publication, the publisher requires a list of all figures, their sources and permission status.

My desire is to extract at least the basis for this from the LaTeX source by modifying \source{} command to also write lines to a List of Sources (los) file.

One example of a figure requiring permission is:

\begin{figure}[htb]
  \centering
  \includegraphics[width=.6\textwidth]{\theChapter/fig/cholera-monmonier-gilbert}
  \caption[\desc{Presentation graphic} Mark Monmonier's re-vision of the Gilbert version of Snow's map, as
  a presentation graphic]{\desc{Presentation graphic} Mark Monmonier's re-vision of the Gilbert version of Snow's map, as
a presentation graphic. \source{Monmonier (1996), \emph{How to Lie with
Maps}, p. 158. Image: permission required, University of Chicago Press.}
}

If this is Fig. 4.10 in the book, I'd like the re-defined \source{} command to write a line to an los file something like:

4.10 Monmonier (1996), \emph{How to Lie with Maps}, p. 158. Image: permission required, University of Chicago Press.

In other words: Wanted: A way to modify \source{} so that it also writes lines to an external file \jobname.los, of the form

fignum source

Can someone help with this?

Answer 1

I took from the linked answer (it's my answer) and added the \source command, writing to .los with \addcontentsline and adding the \thefigure such that it is clear which figure and which source belong together.

\addcontentsline{los}{section}{\thefigure: #1}

adds the relevant content to the .los file with formatting like section is done in a regular ToC. \@starttoc{los} reads the .los file and displays it content. The code is quite similar to \tableofcontents.

\documentclass{book}


\usepackage{xparse}
\usepackage{graphicx}
\usepackage{letltxmacro}


\DeclareRobustCommand{\source}[1]{\emph{Source:} \addcontentsline{los}{section}{\thefigure: #1}#1.}

\makeatletter
\newcommand{\listofsources}{%
  \chapter*{List of Sources}
  \@starttoc{los}
  \clearpage
}
\makeatother


\LetLtxMacro\davidsincludegraphics\includegraphics

\makeatletter

\RenewDocumentCommand{\includegraphics}{sO{}mo}{%
  \IfBooleanTF{#1}{%
    \davidsincludegraphics*[#2]{#3}%
  }{%
    \davidsincludegraphics[#2]{#3}%
  }%
  \begingroup
  % Trying to determine the extension
  \def\loc@l@ext{}
  \IfValueTF{#4}{%
    \def\loc@l@ext{#4}%
  }{%
    \IfFileExists{#3}{%
    }{%
      \IfFileExists{#3.pdf}{%
        \edef\loc@l@ext{.pdf}%
      }{%
        \IfFileExists{#3.jpg}{%
          \edef\loc@l@ext{.jpg}%
        }{%
          \edef\loc@l@ext{.png}%
        }%
      }%
    }%
  }%
  \advance\c@figure by \@ne
  \addtocontents{lfn}{\thefigure\space #3\loc@l@ext}
  \endgroup
}

\def\@starttocbutdonotshowit#1{%
  \begingroup
    \makeatletter
    \if@filesw
      \expandafter\newwrite\csname tf@#1\endcsname
      \immediate\openout \csname tf@#1\endcsname \jobname.#1\relax
    \fi
    \@nobreakfalse
  \endgroup}


\newcommand{\listoffigurenumbernames}{%
  \@starttocbutdonotshowit{lfn}%
}



\begin{document}
\listoffigurenumbernames

\listofsources

\chapter{First}

\begin{figure}[htb]
    \centering
    \includegraphics[width=.49\textwidth]{galton-interp2}[.png]
    \includegraphics[width=.49\textwidth]{galton-interp3}
    \caption{A reconstruction of Galton's method for finding contours of
        approximately equal frequency in the relationship between heights of parents
        and their children. \source{Foo stuff}
    }%
    \label{fig:galton-interp2}
\end{figure}


\begin{figure}[htb]
    \centering
    \includegraphics[width=.49\textwidth]{galton-interp4}
    \includegraphics[width=.49\textwidth]{galton-inter5}
    \caption{A reconstruction of Galton's method for finding contours of
        approximately equal frequency in the relationship between heights of parents
        and their children. 
 \source{Monmonier (1996), \emph{How to Lie with
Maps}, p. 158. Image: permission required, University of Chicago Press.}
    }%
    \label{fig:galton-interp4}
\end{figure}

\chapter{Second}

\begin{figure}[htb]
    \centering
    \includegraphics[width=.49\textwidth]{galton-interp6}
    \includegraphics[width=.49\textwidth]{galton-inter7}
    \caption{A reconstruction of Galton's method for finding contours of
        approximately equal frequency in the relationship between heights of parents
        and their children. 
    }%
    \label{fig:galton-interp5}
\end{figure}


\end{document}