Btukfyl

I have a big image containing several subfigures, each with its own single letter caption already overlayed.

I'd like to reference these subcaptions from the text. As far as I recall something like this was achieavable with subcaption and its phantom commands, but I'm not that sure they covered this particular case.

Is there a way to do it from memoir?

Here's a sample figure to better explain what I'd like to do

It's a single image that I'd prefer not to split. And I'd like to reference the subimages as they were separate figures.

EDIT
Below what I'd do if I could use subcaption, unfortunately as soon as I load it in a document using memoir's own subfigures it messes up with all the caption handling and styling.

So the question remains, is there a way to do phantom subcaptions within memoir?

documentclass{memoir}

usepackage{subcaption}



begin{document}

begin{figure}[t]

  centering

  includegraphics{figure.png}

  begingroup

  phantomsubcaption

  label{fig:somefiga}

  phantomsubcaption

  label{fig:somefigb}

  phantomsubcaption

  label{fig:somefigc}

  phantomsubcaption

  label{fig:somefigd}

  endgroup

  caption{some caption}

  label{fig:somefig}

end{figure}

noindent Figure~ref{fig:somefig} has four subfigures:

figure~ref{fig:somefiga} is a nice fat rectangle, figureref{fig:somefigb}

looks good too. Figures~ref{fig:somefigc}~and~ref{fig:somefigd} could do

better.

end{document}

AFAIU, this cannot be achieved with just native Memoir macros. My own quick-and-dirty (absolutely no warranty) solution was to introduce slightly modified versions of the original native macros (side-by-side diff):

documentclass[a4paper,14pt]{memoir}

usepackage{graphicx}

usepackage{hyperref}

hypersetup{

    colorlinks=true,

    linkcolor=blue,

    filecolor=magenta,      

    urlcolor=cyan,

}



usepackage[all]{hypcap}



% =============== defining the subcaptionphantom ===================================

makeatletter

% begin{macro}{subcaptionphantom}

% cs{subcaptionphantom}oarg{list-entry}marg{caption} is a hidden

% non-printed subcaption. Designed for the case if "(a)", "(b)" are

% already embedded in the figure itself. 

% Roughtly equivalent to cs{phantomsubcaption} from the Lpack{subcaption} package.

%

%    begin{macrocode}

newcommand{subcaptionphantom}{%

  bgroup    

    letlabel=memsub@label

    ifdonemaincaptionelse

      advancecsname c@@captypeendcsname@ne

    fi

    refstepcounter{sub@captype}@contkeep

    @ifnextchar [%

      {@memsubcapphantom{sub@captype}}%

      {@memsubcapphantom{sub@captype}[@empty]}}

%    end{macrocode}

% end{macro}



% begin{macro}{@memsubcapphantom}

% Quick-and-dirty analog of Lpack{memoir} cs{memsubcap}, adapted

% for use in cs{subcaptionphantom}.

%    begin{macrocode}

longdef@memsubcapphantom#1[#2]#3{%

  @tempdima=hsize

  vskipsubfloatcapskip

  ifx @empty #2

    @memsubcaptionphantom{#1}{#3}{#3}%

  else

    @memsubcaptionphantom{#1}{#2}{#3}%

  fi

  vskipsubfloatcapskip

  egroup}

%    end{macrocode}

% end{macro}

%

%

% begin{macro}{@memsubcaptionphantom}

% Quick-and-dirty analog of Lpack{memoir} cs{memsubcaption}, adapted

% for use in cs{memsubcapphantom}.

%    begin{macrocode}

newcommand{@memsubcaptionphantom}[3]{%



  ifx relax#2relax else

    bgroup

      letlabel@gobble

      letprotectstring

      def@memsubcaplabel{@nameuse{@@the#1}}%

      xdef@memsubfigcaptionlist{%

        @memsubfigcaptionlist,%

  {protectnumberline{@memsubcaplabel}noexpand{ignorespaces #2}}}%

    egroup

  fi

  @makesubfloatcaptionphantom{@nameuse{@the#1}}{#3}%

  }



%    end{macrocode}

% end{macro}



% begin{macro}{@makesubfloatcaptionphantom}

% Quick-and-dirty analog of Lpack{memoir} cs{makesubfloatcaption}, adapted

% for use in cs{memsubcaptionphantom}.

%    begin{macrocode}

newcommand{@makesubfloatcaptionphantom}[2]{%

  setbox@tempboxahbox{%

    @subcapsize

    {@subcaplabelfont phantom{#1}}{@subcapfontignorespaces #2}unskip}%

  @tempdimb=-subfloatcapmargin

  multiply@tempdimbtw@

  advance@tempdimb@tempdima

  hb@xt@@tempdima{%

    hss

    ifdim wd@tempboxa >@tempdimb

      phantom{memsubfig@caption{#1}{#2}}%

    else

      if@shortsubcap

        memsubfig@caption{#1}{#2}%

      else

        box@tempboxa

      fi

    fi

    hss}}

%    end{macrocode}

% end{macro}

makeatother

% ===================================================================================



newsubfloat{figure} % allows to use "subbottom"



begin{document}





begin{figure}

centering



hfill%

begin{minipage}[b][b]{0.6linewidth}

centering

    subcaptionphantom{label{sf:1}}

    subcaptionphantom{label{sf:2}}

    framebox[linewidth]{textit{subfigure with embedded (a)}}

    framebox[linewidth]{textit{subfigure with embedded (b)}}

end{minipage}

hfill%

begin{minipage}{0.3linewidth}

    centering

    subbottom[regular subfigure label{sf:3}]%

    {includegraphics[width=0.7linewidth]{example-image}}

end{minipage}





caption{Figure with three subfigureslabel{fig:1}}

end{figure}        



Example refs:newline

Full fig: ref{fig:1}. newline

Sub1: subcaptionref{sf:1}, same as ref{sf:1} (the hidden caption). newline 

Sub2: subcaptionref{sf:2}, same as ref{sf:2} (the hidden caption).  newline

Sub3: subcaptionref{sf:3}, same as ref{sf:3}. newline







clearpage

This text is here to add more space for scrolling.



end{document}

Same in Overleaf.