# Automatic scaling of side by side figures

I'm using a quite satisfying solution for side by side independent caption figures, a solution by which images are sized automatically to same height and to text width, see MWE below.

\documentclass{article}
\usepackage{mwe}
\usepackage{floatrow}

\begin{document}
\blindtext

\begin{figure*}
\CommonHeightRow{\begin{floatrow}
\ffigbox[\FBwidth]{\includegraphics[height=\CommonHeight]{example-image-16x10}}{\caption{A caption.}\label{fig:01}}
\ffigbox[\FBwidth]{\includegraphics[height=\CommonHeight]{example-image-10x16}}{\caption{Another caption.}\label{fig:02}}
\end{floatrow}}
\end{figure*}

\blindtext
\end{document}


However sometimes I would like to limit the overall width of the two figures to something less (say 80%) than text width (retaining the uniform height), but I couldn't find a way to achieve it. (For some reason the naive solution of adding a scalar prefix to \CommonHeight, such as 0.8\CommonHeight, gives an error.)

Thanks in advance for any clue.

Solutions using a package other than floatrow are welcomed, as long as they automatically size images height and overall width by a given percentage of text width, as required.

The floatrow package has two macros, \FRleftmargin and \FRrightmargin which are, by default, \hfill. You can redefine each of them to be \hspace{0.1\textwidth} so the space left for the figures will be 0.8\textwidth.

(rule for scale :)

The definition must be before \begin{floatrow}. If you put it inside \begin{figure} it will be valid for the current figure only, otherwise it will take effect until you redefine it.

I made a little command that will take as argument the desired width of the figures. The command will then balance it and pass to \FRleftmargin and \FRrightmargin. Just call \ThisWidth{0.8\textwidth} after \begin{figure} (or \begin{figure*}, of course :)

\documentclass{article}
\usepackage{mwe}
\usepackage{floatrow}

\makeatletter
\def\ThisWidth#1{%
\@tempdima\dimexpr(\textwidth-#1)/2\relax
\edef\FRleftmargin{\noexpand\hspace*{\the\@tempdima}}%
\edef\FRrightmargin{\noexpand\hspace*{\the\@tempdima}}%
\ignorespaces}
\makeatother

\begin{document}
\pagenumbering{gobble}
\blindtext

\begin{figure*}
\ThisWidth{0.8\textwidth}
\CommonHeightRow{\begin{floatrow}
\ffigbox[\FBwidth]{\includegraphics[height=\CommonHeight]{example-image-16x10}}{\caption{A caption.}\label{fig:01}}
\ffigbox[\FBwidth]{\includegraphics[height=\CommonHeight]{example-image-10x16}}{\caption{Another caption.}\label{fig:02}}
\end{floatrow}}
\rule{0.8\textwidth}{2pt}
\end{figure*}

\blindtext
\end{document}

• Great job, thanks! Maybe you are able to make your solution work (I couldn't) also on this other figure with side by side automatically scaled images with subcaptions (needs subcaption package); \begin{figure*} \ffigbox{}{\CommonHeightRow{\begin{subfloatrow}[2] \ffigbox[\FBwidth]{\includegraphics[height=\CommonHeight]{example-image-10x16}}{\caption{A subcaption.}\label{fig:01a}} \ffigbox[\FBwidth]{\includegraphics[height=\CommonHeight]{example-image-16x10}}{\caption{Another subcaption.}\label{fig:01b}} \end{subfloatrow}} \caption{The figure caption.}\label{fig:01a+01b}} \end{figure*} – mmj May 25 '18 at 9:57
• If you think it's better to start another question I'll be glad to do it, otherwise (if your solution fits both cases) I will update this question. – mmj May 25 '18 at 10:09
• @mmj I looked at your example code... My solution will not work for subfloatrow because it makes \FRleftmargin and \FRrightmargin empty and uses another scheme to place the figures, so simply redefining the environment doesn't work :/ I think your best bet is to ask a new question, so more people will see it. Add a link to this question to give a start :) – Phelype Oleinik May 25 '18 at 16:48
• I started a new question about the similar problem: tex.stackexchange.com/q/433408/28685 – mmj May 25 '18 at 17:26