Legenda de subfigura em subfigura

Question

Eu sou novo no LaTeX. Não tenho certeza de como enquadrar minha pergunta. Mas vou enquadrar para que seja compreensível.

Gostaria de fazer uma subfigura, mas a legenda deve ser

caption of subfigure a-1 caption of subfigure a-2

caption of subfigure b-1 caption of subfigure b-2

                 `caption  of entire figure`

Tentei usar subfigura, mas estou obtendo continuamente a,b,c,d, mas preciso nomeá-los conforme mencionado acima (a-1, a-2, b-1, b-2). Na minha situação, há chances de que as subfiguras estejam em páginas diferentes.

Answer 1

Isso usa a mesma ideia subequationsde amsmath.

\documentclass{article}

\usepackage{graphicx}
\usepackage{subcaption}

\makeatletter
\newcounter{parentsubcaption}
\newenvironment{subsubcaption}
 {\refstepcounter{sub\@captype}%
  \protected@edef\theparentsubcaption{\@nameuse{thesub\@captype}}%
  \setcounter{parentsubcaption}{\value{sub\@captype}}%
  \setcounter{sub\@captype}{0}%
  \@namedef{thesub\@captype}{\theparentsubcaption--\arabic{sub\@captype}}%
  \ignorespaces
}{%
  \setcounter{sub\@captype}{\value{parentsubcaption}}%
  \ignorespacesafterend
}
\makeatother

\begin{document}

\begin{figure}
\centering
\begin{subsubcaption}
\begin{subfigure}{5cm}
\includegraphics[width=\linewidth]{example-image}
\caption{caption of subfigure a--1}\label{a--1}
\end{subfigure}\qquad
\begin{subfigure}{5cm}
\includegraphics[width=\linewidth]{example-image}
\caption{caption of subfigure a--2}\label{a--2}
\end{subfigure}
\end{subsubcaption}

\begin{subsubcaption}
\begin{subfigure}{5cm}
\includegraphics[width=\linewidth]{example-image}
\caption{caption of subfigure b--1}\label{b--1}
\end{subfigure}\qquad
\begin{subfigure}{5cm}
\includegraphics[width=\linewidth]{example-image}
\caption{caption of subfigure b--2}\label{b--2}
\end{subfigure}
\end{subsubcaption}

\caption{caption  of entire figure}
\end{figure}

References:
\ref{a--1} and \subref{a--1};
\ref{b--1} and \subref{b--1}.

\end{document}

EDITAR

O código acima realmente não funciona se mais ambientes de figuras usarem arquivos subsubcaption. Aqui está uma solução alternativa que tenta funcionar bem também com o \ContinuedFloat.

\documentclass{article}

\usepackage{graphicx}
\usepackage{subcaption}
\usepackage{etoolbox}
\makeatletter
\newif\ifsubsubcaption@ContinuedFloat
\newif\ifsubsubcaption@nonfirst
\patchcmd{\ContinuedFloat}
  {\caption@ContinuedFloat}
  {\subsubcaption@ContinuedFloattrue\caption@ContinuedFloat}
  {}{}

\newcounter{parentsubcaption}
\newenvironment{subsubcaption}
 {\refstepcounter{sub\@captype}%
  \protected@edef\theparentsubcaption{\@nameuse{thesub\@captype}}%
  \setcounter{parentsubcaption}{\value{sub\@captype}}%
  \setcounter{sub\@captype}{0}%
  \@namedef{thesub\@captype}{\theparentsubcaption--\arabic{sub\@captype}}%
  \ignorespaces
}{%
  \setcounter{sub\@captype}{\value{parentsubcaption}}%
  \ignorespacesafterend
}
\BeforeBeginEnvironment{subsubcaption}{%
  \ifsubsubcaption@ContinuedFloat
  \else
    \ifsubsubcaption@nonfirst
    \else
      \subsubcaption@nonfirsttrue
      \setcounter{sub\@captype}{0}%
    \fi
  \fi
}
\makeatother

\begin{document}

\begin{figure}
\centering
\begin{subsubcaption}
\begin{subfigure}{5cm}
\includegraphics[width=\linewidth]{example-image}
\caption{caption of subfigure a--1}\label{a--1}
\end{subfigure}\qquad
\begin{subfigure}{5cm}
\includegraphics[width=\linewidth]{example-image}
\caption{caption of subfigure a--2}\label{a--2}
\end{subfigure}
\end{subsubcaption}

\begin{subsubcaption}
\begin{subfigure}{5cm}
\includegraphics[width=\linewidth]{example-image}
\caption{caption of subfigure b--1}\label{b--1}
\end{subfigure}\qquad
\begin{subfigure}{5cm}
\includegraphics[width=\linewidth]{example-image}
\caption{caption of subfigure b--2}\label{b--2}
\end{subfigure}
\end{subsubcaption}

\caption{caption  of entire figure}
\end{figure}

References:
\ref{a--1} and \subref{a--1};
\ref{b--1} and \subref{b--1}.

\begin{figure}
\ContinuedFloat
\centering
\begin{subsubcaption}
\begin{subfigure}{5cm}
\includegraphics[width=\linewidth]{example-image}
\caption{caption of subfigure c--1}\label{c--1}
\end{subfigure}\qquad
\begin{subfigure}{5cm}
\includegraphics[width=\linewidth]{example-image}
\caption{caption of subfigure c--2}\label{c--2}
\end{subfigure}
\end{subsubcaption}

\begin{subsubcaption}
\begin{subfigure}{5cm}
\includegraphics[width=\linewidth]{example-image}
\caption{caption of subfigure d--1}\label{d--1}
\end{subfigure}\qquad
\begin{subfigure}{5cm}
\includegraphics[width=\linewidth]{example-image}
\caption{caption of subfigure d--2}\label{d--2}
\end{subfigure}
\end{subsubcaption}

\caption{caption  of entire figure (continued)}
\end{figure}

\begin{figure}
\centering
\begin{subsubcaption}
\begin{subfigure}{5cm}
\includegraphics[width=\linewidth]{example-image}
\caption{caption of subfigure a--1}\label{a--1-x}
\end{subfigure}\qquad
\begin{subfigure}{5cm}
\includegraphics[width=\linewidth]{example-image}
\caption{caption of subfigure a--2}\label{a--2-x}
\end{subfigure}
\end{subsubcaption}

\begin{subsubcaption}
\begin{subfigure}{5cm}
\includegraphics[width=\linewidth]{example-image}
\caption{caption of subfigure b--1}\label{b--1-x}
\end{subfigure}\qquad
\begin{subfigure}{5cm}
\includegraphics[width=\linewidth]{example-image}
\caption{caption of subfigure b--2}\label{b--2-x}
\end{subfigure}
\end{subsubcaption}

\caption{caption  of entire figure}
\end{figure}

\end{document}

A figura de “continuação” tem os rótulos c e d, enquanto a figura “nova” seguinte tem a e b novamente.