customizing cleveref for pair of subfigure references: [1a and b] instead of [1a and 1b]

Question

I am using the cleveref package and I am very happy with it. However, I encountered one problem I wasn't able to solve. I am probably just not combining the syntax correctly. This is highly connected to the question already asked, here: Crossreference in Ref Range [(1a-1e) to (1a-e)] I am sorry if this is already answered.

The above thread explains how to reference ranges of subequations (or floats) like 1a to e, rather than the default 1a to 1e. I would like to have the same feature for a pair of references combined by an "and", namely: 1a and b rather than the default 1a and 1b.

Here is a MWE:

\documentclass{book}

\usepackage{cleveref}
\usepackage{subfig}
\crefrangelabelformat{figure}{#3#1#4--#5\crefstripprefix{#1}{#2}#6}
\crefmultiformat{figure}{figs.~#2#1#3}{ and~#2#1#3}{, #2#1#3}{ and~#2#1#3}

\begin{document}
\begin{figure}
  \centering
  \subfloat[][]{\rule{2.cm}{2.cm}\label{subfig:1a}}
  \subfloat[][]{\rule{2.cm}{2.cm}\label{subfig:1b}}\\
  \subfloat[][]{\rule{2.cm}{2.cm}\label{subfig:1c}}
  \subfloat[][]{\rule{2.cm}{2.cm}\label{subfig:1d}}\\
  \caption{\label{fig:1}my figures}
\end{figure}

Referencing a range works as wanted and gives figs. 1a-b: \cref{subfig:1a,subfig:1b,subfig:1c,subfig:1d}.\\
But, referencing a pair gives \cref{subfig:1a,subfig:1b}, rather than the desired figs. 1a and b.\\ 

\end{document}

I think combining \crefstripprefix together with \crefmultiformat{figure} (which I use in the MWE to remove the "()") could give me the desired result. But I am not able to get the correct syntax to make this work, since I am pretty unfamiliar with the deep-down latex syntax.

Answer 1

In your definition of \crefmultiformat you want to use \crefrefstripprefix in the second argument using a value from the first argument. This can be achieved as follows:

\crefmultiformat{figure}{figs.~#2#1\xdef\mycreffirstarg{#1}#3}%
 { and~#2{\crefstripprefix{\mycreffirstarg}{#1}}#3}{, #2#1#3}{ and~#2#1#3}

Also you need to define \crefrangelabelformat in a similar way (update following comments).

\documentclass{book}
\usepackage{cleveref}
\usepackage{subfig}
\crefrangelabelformat{figure}{#3#1\xdef\mycreffirstarg{#1}#4--%
#5\crefstripprefix{#1}{#2}#6}
\crefmultiformat{figure}{figs.~#2#1\xdef\mycreffirstarg{#1}#3}%
{ and~#2{\crefstripprefix{\mycreffirstarg}{#1}}#3}%
{, #2{\crefstripprefix{\mycreffirstarg}{#1}}#3}%
{ and~#2{\crefstripprefix{\mycreffirstarg}{#1}}#3}
\crefrangemultiformat{figure}{figs.~#3#1#4--#5\crefstripprefix{#1}{#2}#6}%
{ and~#3#1#4--#5\crefstripprefix{#1}{#2}#6}%
{, #3#1#4--#5\crefstripprefix{#1}{#2}#6}%
{ and~#3#1#4--#5\crefstripprefix{#1}{#2}#6}
\begin{document}
\begin{figure}
  \centering
  \subfloat[][]{\rule{2.cm}{2.cm}\label{subfig:1a}}
  \subfloat[][]{\rule{2.cm}{2.cm}\label{subfig:1b}}\
  \subfloat[][]{\rule{2.cm}{2.cm}\label{subfig:1c}}
  \subfloat[][]{\rule{2.cm}{2.cm}\label{subfig:1d}}\
  \subfloat[][]{\rule{2.cm}{2.cm}\label{subfig:1e}}
  \caption{\label{fig:1}my figures}
\end{figure}
\tracingmacros=1
Referencing a range works as wanted and gives figs.~1a--d:
\cref{subfig:1a,subfig:1b,subfig:1c,subfig:1d}.
Gives figs.~1a--c and e: \cref{subfig:1a,subfig:1b,subfig:1c,subfig:1e}.
Gives figs.~1a, b, d and e: \cref{subfig:1a,subfig:1b,subfig:1d,subfig:1e}.
Also referencing a pair gives \cref{subfig:1a,subfig:1b}, which is
then the desired figs.~1a and~b.
\end{document}

Answer 2

Using the subcaption package instead of subfig will get you most of the way. subcaption provides a \subref command, which gives you only the subfigure index without the figure number.

\documentclass{article}
\usepackage{graphicx}
\usepackage{cleveref}
\usepackage{subcaption}
\begin{document}
\begin{figure}
  \centering
  \begin{subfigure}{0.2\textwidth}
  \includegraphics[width=\linewidth]{example-image-a}
  \caption{Image a}
  \label{subfig:foo}
  \end{subfigure}
  \begin{subfigure}{0.2\textwidth}
  \includegraphics[width=\linewidth]{example-image-b}
  \caption{Image b}
  \label{subfig:bar}
  \end{subfigure}\\
  \begin{subfigure}{0.2\textwidth}
  \includegraphics[width=\linewidth]{example-image-c}
  \caption{Image c}
  \label{subfig:baz}
  \end{subfigure}
  \begin{subfigure}{0.2\textwidth}
  \includegraphics[width=\linewidth]{example-image}
  \caption{Image d}
  \label{subfig:qux}
  \end{subfigure}
  \caption{\label{fig:1}my figures}
\end{figure}
Referencing a range works as wanted and gives figs.~\ref{subfig:foo}--\subref{subfig:bar}. There is also \cref{subfig:foo,subfig:bar,subfig:baz,subfig:qux}.
A pair can be referenced like figs.~\ref{subfig:foo} to \subref{subfig:baz}.
\end{document}