%% Herbert Voss <hvoss@tug.org>
%% Copyright (C) 2025
%%
%% This program can be redistributed and/or modified under the terms
%% of the LaTeX Project Public License Distributed from CTAN archives
%% in directory macros/latex/base/lppl.txt.
%%
%%  width=2\paperwidth, height=variable
%%
%% ||1in+evenside --- |1in+oddside ---||       Image is 2\paperwidth wide, height is variable or user set
%
\def\do@hvFloat@doubleFullPage#1{%  image on left and right page with caption before/below/right/after
  % #1-> not used, caption always below lefr or below right
  \setcounter{topnumber}{1}%
  \setcounter{dbltopnumber}{1}%
  \expandafter\hvFloatSet\expandafter{\hv@save@setting}%    
%  \ifx\hvSet@capPos\hv@Right\else\ifx\hvSet@capPos\hv@Left\else
%    \let\hvSet@capPos\hv@Right
%  \fi\fi
  \ifx\hv@caption@format\@empty\else\expandafter\captionsetup\expandafter{\hv@caption@format}\fi
      \ifx\hv@subcaption@format\@empty\else
        \expandafter
           \captionsetup\expandafter[\expandafter s\expandafter u\expandafter b\expandafter]\expandafter
                             {\hv@subcaption@format}%
  \fi
  \let\c@hv@tempCNTfigA\c@figure
  \let\c@hv@tempCNTtabA\c@table
  \checkoddpage
  \ifoddpage
    \if@twocolumn
      \if@firstcolumn
        \afterpage{afterpage{\do@hvFloat@doubleFullPage@ObjectAndCaption}}%  2nd Col and newpage
      \else
        \do@hvFloat@doubleFullPage@ObjectAndCaption% odd, 2nd col -> no newpage
      \fi
    \else % onecol
      \afterpage{\do@hvFloat@doubleFullPage@ObjectAndCaption}% oddpage->newpage
    \fi % end \if@twocolumn
  \else% evenpage 
    %---------
    \global\savebox{\hvObjectBox}{\ifhv@useOBox\usebox{\hvOBox}\else\hv@floatObject\fi}%
     \if@twocolumn
        \if@firstcolumn
          \afterpage{\afterpage{\afterpage{\do@hvFloat@doubleFullPage@ObjectAndCaption}}}%  ->2nd Col left page and newpage
        \else
          \afterpage{\afterpage{\do@hvFloat@doubleFullPage@ObjectAndCaption}}% ->newpage ( 2columns)
        \fi
     \else % onecol
        \afterpage{\afterpage{\do@hvFloat@doubleFullPage@ObjectAndCaption}}% evenpage->newpage->newpage
     \fi % end \if@twocolumn
  \fi% main ifoddpage
  \endgroup% started at main macro \hvFloat
}

\def\do@hvFloat@doubleFullPage@ObjectAndCaption{%
  \begin{\hv@floatType*}[t]
    \hv@set@noverticalSpace
    \hfuzz=\maxdimen
    \vfuzz=\maxdimen
    \expandafter\hvFloatSet\expandafter{\hv@save@setting}% 
    \hv@leftPageObjectWidth=\dimexpr\paperwidth-\hvSet@bindCorrection%
    \global\savebox{\hvObjectBox}{\ifhv@useOBox\usebox{\hvOBox}\else\hv@floatObject\fi}%
    \vspace*{\the\dimexpr-1in-\voffset-\topmargin-\headheight-\headsep}%-\baselineskip-\parskip+1.5\lineskip}%  no interlineskip
    \hspace*{\the\dimexpr-\evensidemargin-\parindent-1in}%
    \clipbox*{0 -\depth{} \hv@leftPageObjectWidth{} \height}{\usebox\hvObjectBox}%
    \ifx\hvSet@capPos\hv@Left %  left side a caption
      \ifhv@onlyText
        \hv@longCap
      \else
        \ifx\hv@shortCap\@empty
          \captionof{\hv@floatType}{\hv@longCap}%
        \else
          \captionof{\hv@floatType}[\hv@shortCap]{\hv@longCap}%
        \fi
      \fi
      \ifx\hv@label\@empty\else
        \expandafter\label\expandafter{\hv@label-cap}%
        \expandafter\label\expandafter{\hv@label}%
      \fi
    \else
      \ifx\hv@floatType\hv@figure
        \global\refstepcounter{hv@tempCNTfigA}%
      \else
        \global\refstepcounter{hv@tempCNTtabA}%   before caption
      \fi
      \ifx\hv@label\@empty\else
         \expandafter\label\expandafter{\hv@label}%
      \fi
      \ifhv@global@sameHeight
        \par\noindent\phantom{\parbox{\textwidth}{\caption*{\hv@longCap}}}%
%      \vspace{-2pt}%
      \fi
    \fi
    \hv@reset@noverticalSpace
  \end{\hv@floatType*}%
  %  start right half of the image ----------------- RIGHT
  \begin{\hv@floatType*}[t]
    \hv@set@noverticalSpace
    \hfuzz=\maxdimen
    \expandafter\hvFloatSet\expandafter{\hv@save@setting}% 
    \hv@leftPageObjectWidth=\dimexpr\paperwidth-\hvSet@bindCorrection
    \global\savebox{\hvObjectBox}{\ifhv@useOBox\usebox{\hvOBox}\else\hv@floatObject\fi}%
    \vspace*{\the\dimexpr-1in-\voffset-\topmargin-\headheight-\headsep}%-\baselineskip-\parskip+1.5\lineskip}%  no interlineskip
    \hspace*{\the\dimexpr-1in-\oddsidemargin+\hvSet@bindCorrection}%
    \clipbox*{\the\hv@leftPageObjectWidth{} -\depth{} \width{} \height{}}{\usebox\hvObjectBox}%
    \ifx\hvSet@capPos\hv@Left %  caption is already set on the left side
      \expandafter\label\expandafter{\hv@label-2}%
      \ifhv@global@sameHeight
        \par\noindent\phantom{\parbox{\textwidth}{\caption*{\hv@longCap}}}%
      \fi
    \else %  Caption on right
      \ifhv@onlyText
        \hv@longCap
      \else
        \ifx\hv@shortCap\@empty
          \captionof{\hv@floatType}{\hv@longCap}%
        \else
          \captionof{\hv@floatType}[\hv@shortCap]{\hv@longCap}%
        \fi
      \fi
      \ifx\hv@label\@empty\else
        \expandafter\label\expandafter{\hv@label-cap}%
        \expandafter\label\expandafter{\hv@label-2}%
      \fi
    \fi
    \hv@reset@noverticalSpace
  \end{\hv@floatType*}%
}