Graphics, Figures & Tables ⇒ Small drawn Picture within Caption

[thomgraf]

Has anyone an idea how to use a tikzpicture environment within a figure caption? What I want is, plot a blue circle withing a figure caption, like this.

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\begin{figure}[ht]
%...
\caption{CaptionText \begin{tikzpicture} \draw[thick, color=blue, fill=blue] plot[mark=*, mark options={scale=1.3}] (0,0); \end{tikzpicture} CaptionText.}
\end{figure}

Within regular text, this works fine with this.

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RegularText \begin{tikzpicture} \draw[thick, color=blue, fill=blue] plot[mark=*, mark options={scale=1.3}] (0,0); \end{tikzpicture} RegularText

Thank you!

[thomgraf]

The solution is this one.

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{\protect\tikz \protect\draw[thick, color=blue, fill=blue] plot[mark=*, mark options={scale=1.3}] (0,0);}

[cgnieder]

It seems you found the solution yourself. The problem is that the argument of \caption is what's called a moving argument. This means that its contents at some point will be completely expanded, usually when it is written to an auxiliary file as is the case for captions. Figure captions are written to the lof file which is used by the \listoffigures to display the list of figures. In a moving argument one cannot use fragile commands. fragile commands are commands that are not expandable and which are not taken care of by LaTeX's \protected@write. As you've experienced \tikz and \draw are not expandable which means they must be protected inside a moving argument such as \caption's which is usually done by placing \protect in front of them.

Regards

[localghost]

You seem to do some plots with TikZ/PGF. The pgfplots package not only makes plotting easier but also offers a nice feature that simply works with the known mechanism of \label and \ref. An example derived from Section 4.8.6 of the package manual.

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\documentclass[11pt]{article}
\usepackage[T1]{fontenc}
\usepackage{pgfplots}
\pgfplotsset{
  compat=newest,
  xlabel near ticks,
  ylabel near ticks
}

\begin{document}
  \begin{figure}[!htb]
    \centering
    \begin{tikzpicture}[baseline]
      \begin{axis}
        \addplot+[
          only marks,
          samples=15,
          error bars/y dir=both,error bars/y fixed=2.5
        ] {3*x+2.5*rand};
        \label{pgfplots:label1}
        \addplot+[mark=none] {3*x};
        \label{pgfplots:label2}
        \addplot {4*cos(deg(x))};
        \label{pgfplots:label3}
      \end{axis}
    \end{tikzpicture}
    \caption{The estimations \protect\ref{pgfplots:label1} which are subjected to noise. It appears the model \protect\ref{pgfplots:label2} fits the data appropriately. Finally, \protect\ref{pgfplots:label3} is only here to get three examples.}
    \label{fig:pgfplots-labels}
  \end{figure}
\end{document}

All \ref commands need to be prefixed by \protect in order to avoid problems with \listoffigures (see above code). The output is attached.


Thorsten