How do I set the minimum width of a subfigure?

Question

I have:

\subfigure[blah blah blah.]
{
\begin{tikzpicture}[/MyStyle]
    ... some stuff...
\end{tikzpicture} 
}

But "some stuff" is not that wide and the text in the subfigure produces a lot of underfull hboxes. I want to make the subfigure wider. How do I do that?

Answer 1

A general approach for customizing the width and the height of a subfigure is using the adjustbox package. It provides features for trimming (also with negative value, so enlarging), clipping, scaling, rotating etc. which can be applied also to TikZ pictures.

An example where the subfigure has been made wider by 1 cm on the left and on the right:

\documentclass{article}
\usepackage[demo]{graphicx}
\usepackage{adjustbox}
\usepackage{subfig}
\usepackage{tikz}
\usetikzlibrary{positioning}
\begin{document}
\begin{figure}
\subfloat{Test figure}
\subfloat[The ball]{%
  \trimbox{-1cm 0cm -1cm 0cm}{%
    \begin{tikzpicture}
      \node[circle,shading=ball,ball color=red!80!white,minimum size=2cm] {};
    \end{tikzpicture}}}
\subfloat{Test figure}
\end{figure}
\end{document}

Without \trimbox:

With \trimbox:

Answer 2

You could alter the width of the tikz picture. I don't know if subfigure itself has any width attribute. It normally inherits its size from whatever is inside it, as far as I know

Answer 3

Another option is to use the subfigure environment from the subcaption package.

\documentclass{article}
\usepackage{caption}
\usepackage{subcaption}

\usepackage{tikz}
\usetikzlibrary{positioning}

\begin{document}
\begin{figure}
\begin{subfigure}{0.09\textwidth}
\centering
\rule{30pt}{20pt}
\caption{}
\end{subfigure}
\begin{subfigure}{0.8\textwidth}
\centering
    \begin{tikzpicture}
      \node[circle,shading=ball,ball color=red!80!white,minimum size=2cm] {};
    \end{tikzpicture}
    \caption{The ball}
\end{subfigure}
\begin{subfigure}{0.09\textwidth}
\centering
\rule{30pt}{20pt}
\caption{}
\end{subfigure}
\end{figure}
\end{document}