How to center align subfigures and bottom align the captions?

Question

How can I center align the two subfigures and align the caption (a), (b) for the two figures like this?
Assume that the image sizes are unknown. (or probably I can input it manually)
I saw some previous posts relating to this but they used minipages which I couldn't apply successfuly to my subfigures.

\documentclass[journal]{IEEEtran}
\usepackage[]{subfig}
\usepackage{stfloats}
\usepackage{float}
\usepackage{graphicx}
\begin{document}
%
\begin{figure}[!t]
\centering
\subfloat[]{\includegraphics[width=0.25\linewidth, height=30pt]{example-image-a}
\label{fig_first_case}}
\hfil
\subfloat[]{\includegraphics[width=0.25\linewidth, height=60pt]{example-image-b}
\label{fig_second_case}}
\caption{Example of two figures. (a) The first figure. (b) The second figure}
\label{fig_subfig}
\end{figure}
%
\end{document}

score 2 · Answer 1 · answered Aug 31 '22 at 13:40

2

This is easy with the floatrow package:

    \documentclass[journal]{IEEEtran}
    \usepackage[]{subfig}
    \usepackage{stfloats}
    \usepackage{graphicx}
    \usepackage{floatrow}
\begin{document}

\begin{figure*}[!t]
\floatsetup{heightadjust=all, valign=c}
\centering
\ffigbox{\begin{subfloatrow}
\ffigbox{\caption{}\label{fig_first_case}}{\includegraphics[width=0.25\linewidth, height=30pt]{example-image-a}
}
\hfil
\ffigbox{\caption{}\label{fig_second_case}}{\includegraphics[width=0.25\linewidth, height=60pt]{example-image-b}
}
\end{subfloatrow}}{\caption{Example of two figures. (a) The first figure. (b) The second figure}}
\end{figure*}

\end{document}

answered Aug 31 '22 at 13:40

Bernard

271,350

Thanks, how can I keep the same caption style as the original like Fig. 1 instead of Fig. 1:? The caption style is not compatible with IEEEtran. – emnha Aug 31 '22 at 15:50
I got some other warning as well from overleaf: Package caption Warning: Unknown document class (or package), standard defaults will be used. See the caption package documentation for explanation. Package caption Warning: \setcaptionsubtype without \DeclareCaptionSubType. This is not designed to work; you could try replacing thesubfig' package with subcaption' to resolve this problem which occurred on input line 18. See the caption package documentation for explanation – emnha Aug 31 '22 at 16:02
floatrow cooperates with the caption package . You might try \captionsetup{labelsep=none}. – Bernard Aug 31 '22 at 16:07
Where should I put this? – emnha Sep 01 '22 at 04:15
@emnha: either in the preamble, or just after the beginnning of the environment if it is to be used only once. – Bernard Sep 01 '22 at 08:05

score 2 · Accepted Answer · answered Sep 01 '22 at 09:48

2

You should call subfig with the caption=false option, otherwise the caption style of IEEEtran would be overridden: this will annoy the copy editors of the journal you're submitting to (and maybe cause rejection).

For just one case you can do it manually:

\documentclass[journal]{IEEEtran}
\usepackage[caption=false]{subfig}
\usepackage{graphicx}
\MakeRobust{\subref}
\newsavebox{\leftimage}
\newsavebox{\rightimage}
\newlength{\imageheight}
\newcommand{\placeimage}[1]{%
  \raisebox{\dimexpr(\imageheight-\height)/2}{\usebox{#1}}%
}
\begin{document}
\begin{figure*}[!t]
\centering
\sbox{\leftimage}{\includegraphics[width=0.25\linewidth, height=30pt]{example-image-a}}
\sbox{\rightimage}{\includegraphics[width=0.25\linewidth, height=60pt]{example-image-b}}
\setlength{\imageheight}{\ht\leftimage}
\ifdim\ht\rightimage>\imageheight
  \setlength{\imageheight}{\ht\rightimage}
\fi
\subfloat[]{\placeimage{\leftimage}\label{fig_first_case}}\hfil
\subfloat[]{\placeimage{\rightimage}\label{fig_second_case}}
\caption{%
  Example of two figures.
  \subref{fig_first_case}~The first figure.
  \subref{fig_second_case}~The second figure.
}
\label{fig_subfig}
\end{figure*}
\end{document}

Both images are measured and the larger vertical size is determined. Then the boxes containing the images are raised by the appropriate amount.

answered Sep 01 '22 at 09:48

egreg

1,121,712

This is very nice but I have some problem with reference hope you can help. It's related to my previous post. https://tex.stackexchange.com/questions/655002/how-to-refer-subfigure-with-parentheses-as-fig-1a-instead-of-fig-1a I used \renewcommand\thesubfigure{(\alph{subfigure})} as Zxcvasdf mentioned to avoid double parenthesis like ((a)) and also refer to figure as Fig. 1(a) instead of Fig. 1a but now I got the problem like Example of two figures. ((a)) The first figure. ((b)) The second figure. – emnha Sep 01 '22 at 19:17
@emnha That's a known problem with subfig. – egreg Sep 01 '22 at 20:01
How can I fix this? \renewcommand\thesubfigure{(\alph{subfigure})} that Zxcvasdf suggested work for reference but it doesn't remove double parenthesis in the caption of your solution. – emnha Sep 01 '22 at 20:06
@emnha Did you look at https://tex.stackexchange.com/q/16291/4427 ? – egreg Sep 01 '22 at 20:07
I did and used \renewcommand\thesubfigure{(\alph{subfigure})} that Zxcvasdf suggested and it fixed the problem of reference in the text. However, it doesn't work in figure caption in your code. – emnha Sep 01 '22 at 20:40
I solved it with \subref*{} in the caption! – emnha Sep 01 '22 at 22:40

John Kormylo · Answer 3 · 2022-08-31T22:43:05.563

In case IEEE has a problem with floatrow...

The tricky ibt was matching the spacing used by \subfloat (NOT \abovecaptionskip or \belowcaptionskip).

\documentclass[journal]{IEEEtran}
\usepackage{graphicx}
\usepackage{subfig}% for \thesubfigure
\begin{document}
%
\begin{figure*}[!t]
\centering
\tabcolsep=0.0833\linewidth% 0.5\linewidth / 6 (3 equal gaps)
\belowcaptionskip=-\baselineskip
\begin{tabular}{@{}cc@{}}
\raisebox{-0.5\height}{\includegraphics[width=0.25\linewidth, height=30pt]{example-image-a}} &
\raisebox{-0.5\height}{\includegraphics[width=0.25\linewidth, height=60pt]{example-image-b}} \
\refstepcounter{subfigure}\label{fig_first_case}\raisebox{-1ex}{(\thesubfigure)} &
\refstepcounter{subfigure}\label{fig_second_case}\raisebox{-1ex}{(\thesubfigure)}
\end{tabular}
\caption{Example of two figures. (a) The first figure. (b) The second figure}
\label{fig_subfig}
\end{figure*}
%
\end{document}

How can I keep the caption style as Fig. 1 instead of Fig. 1: which is not compatible with IEEEtran? — emnha, Sep 01 '22 at 04:10
You can use \caption{} to get Fig.1 with no colon, but adding a colon before the title is IEEE standard. — John Kormylo, Sep 01 '22 at 13:32

How to center align subfigures and bottom align the captions?

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