%D \module
%D   [       file=page-imp, % was: core-pag,
%D        version=1998.01.15,
%D          title=\CONTEXT\ Page Macros,
%D       subtitle=Pagebody Building (Imposition),
%D         author=Hans Hagen,
%D           date=\currentdate,
%D      copyright={PRAGMA / Hans Hagen \& Ton Otten}]
%C
%C This module is part of the \CONTEXT\ macro||package and is
%C therefore copyrighted by \PRAGMA. See mreadme.pdf for
%C details.

% much of this can more to run time loading !

\writestatus{loading}{ConTeXt Page Macros / Pagebody Building}

\unprotect

% sizing bug:
%
% \setuppapersize[A4][A4,landscape] \setuparranging[2UP] \showframe
%
% \starttext \dorecurse{10}{\input tufte \par} \stoptext

\newif\ifclipprintbox \clipprintboxtrue % todo: conditional
%newif\ifclippagebox  \clippageboxtrue

\def\clippedprintbox#1#2% can be made more efficient, see other clipper
  {\ifclipprintbox
     \!!widthc \pagebackgroundoffset
     \!!widtha \dimexpr\paperwidth + \!!widthc\relax
     \!!heighta\dimexpr\paperheight+2\!!widthc\relax
     \setbox#2\vbox to \paperheight{\vfill\box#2}%
     \ht#2\paperheight
     \wd#2\paperwidth
     \setbox#2\vbox
       {\framed
          [\c!offset=\!!widthc,\c!strut=\v!no,\c!frame=\v!off]
          {\box#2}}%
     \setbox#2\hbox to \paperwidth
       {\ifcase#1\relax
          \!!widthb\zeropoint
          \hskip-\!!widthc
        \else
          \!!widthb\!!widthc
        \fi
        \lower\!!widthc\hbox
          {\clip
             [\c!width=\!!widtha,\c!height=\!!heighta,
              \c!hoffset=\!!widthb,\c!voffset=\zeropoint]
             {\box#2}}}%
     \wd#2\paperwidth
     \ht#2\paperheight
   \fi
   \box#2\relax}

\let\clippagebox \gobbleoneargument
\let\clipprintbox\gobbleoneargument

% \setuppagenumbering[alternative=doublesided]
% \setupcolors[state=start]
% \setuppapersize[A4][A4,oversized]
% \setuplayout[location=middle,clipoffset=5mm]
% \setupbackgrounds
%   [page]
%   [frame=on,rulethickness=1mm,
%    backgroundoffset=10mm,background=color,backgroundcolor=red]
% \starttext \dorecurse{10}{\input tufte \par} \stoptext

\def\clippagebox % skip fast over false
  {\ifdim\@@lyclipoffset>\zeropoint
      \expandafter\doclippagebox
   \else
      \expandafter\gobbleoneargument
   \fi}

\def\doclippagebox#1%
  {\!!widtha \wd#1%
   \!!heighta\ht#1%
   \!!deptha \dp#1%
   \setbox#1\hbox
     {\!!widthb \@@lyclipoffset
      \advance\!!heighta\dimexpr\!!deptha+2\!!widthb\relax
      \advance\!!widtha \!!widthb
      \doifbothsides
        {\advance\!!widtha\!!widthb \!!widthc-\!!widthb \hskip\!!widthc}%
        {\!!widthc\zeropoint}
        {\!!widthc-\!!widthb \hskip\!!widthc}%
      \lower\!!widthb\hbox
        {\clip
           [\c!hoffset=\!!widthc,
            \c!voffset=-\!!widthb,
              \c!width=\!!widtha,
             \c!height=\!!heighta]%
           {\box#1}}}%
   \wd#1\!!widtha
   \ht#1\!!heighta
   \dp#1\!!deptha}

%D \macros
%D   {starttextdata}
%D
%D This is a user macro (appending to every last shipout is not
%D really user friendly.

\newtoks\collectedtextdata

\long\unexpanded\def\starttextdata#1\stoptextdata
  {\doglobal\appendtoks#1\to\collectedtextdata}

\def\flushtextdata
  {\vsmashed{\the\collectedtextdata}% all dimensions zero
   \global\collectedtextdata\emptytoks
   \globallet\flushtextdata\donothing}

\prependtoks \flushtextdata \to \everylastshipout

\def\installpagehandler#1#2%                  % a handler takes one argument: something to be boxed
  {\setgvalue{\??pp:\c!method:#1}##1{#2{##1}}} % and shipped out (don't depend on the exact package)

\installpagehandler\v!normal
  {\ifarrangingpages\expandafter\actualarrange\else\expandafter\actualshipout\fi}

\def\myshipout#1%
 {\beforeshipout % voor de pagebody dus !
  \dontshowcomposition
  \dontcomplain
  \executeifdefined{\??pp:\c!method:\@@ppmethod}\gobbleoneargument{#1}%
  \setnextrealpageno
  \aftershipout}

\newbox\postponedcontent

\def\flushatshipout
  {\dowithnextbox
     {\global\setbox\postponedcontent\hbox to \zeropoint
        {%\hskip-\maxdimen % niet hier, gaat mis in acrobat (clipt)
         \unhbox\postponedcontent\unhbox\nextbox}% was \box
      \global\ht\postponedcontent\zeropoint
      \global\dp\postponedcontent\zeropoint
      \global\wd\postponedcontent\zeropoint}%
   \hbox}

% \starttypen
% \def\pagestoshipout{1,3,5}
% \stoptypen

\newcount\shippedoutpages
\newcount\combinedpagescounter

\let\pagestoshipout\empty        % {1,3,6}
\newconstant\whichpagetoshipout  % 0=all 1=odd 2=even

\newbox\shipoutscratchbox

\def\actualshipout#1% todo: less callbacks
  {\global\advance\shippedoutpages\plusone
   % this is not resource safe!
   \ifx\pagestoshipout\empty
     \ifcase\whichpagetoshipout\relax
       \donetrue
     \or % 1
       \ifodd\shippedoutpages\relax\donetrue\else\donefalse\fi
     \or % 2
       \ifodd\shippedoutpages\relax\donefalse\else\donetrue\fi
     \else
       \donetrue
     \fi
   \else % testen, aangepast / expanded nodig ?
     \normalexpanded{\noexpand\doifinsetelse{\the\shippedoutpages}{\pagestoshipout}}%
       \donetrue\donefalse
   \fi
   \ifdone
     \begingroup
     \setbox\shipoutscratchbox\hbox{#1}% just in case there are objects there, hook for testing
     \finalizeshipoutbox\shipoutscratchbox
     \setbox\scratchbox\hbox
       {% before the main one !
        \ifcase\realfolio \or
          \the\everyfirstshipout
          \global\everyfirstshipout\emptytoks
        \fi
        % the main one
        \the\everyshipout\relax
        % always last (and after the main one)
        \ifnum\realpageno=\lastpage\relax
          \the\everylastshipout
          \global\everylastshipout\emptytoks
        \fi}%
     \smashbox\scratchbox
     \shipout\vbox
       {\offinterlineskip
        \scratchdimen-1in % to be done in luatex: zero that one
        \vskip\scratchdimen
        \hskip\scratchdimen
        \hbox % \setbox0=\box.. is nicer
          {\box\scratchbox
           \ifvoid\postponedcontent\else\box\postponedcontent\fi % evt ver naar links !
           \box\shipoutscratchbox}}%
     \endgroup
   \else
     \message
       {[\ifarrangingpages arranged \fi page
         \ifarrangingpages\the\arrangeno\else\the\realpageno\fi\normalspace
         not flushed]}%
     \setbox0\hbox{#1}%
     \deadcycles\zerocount
   \fi}

\def\actualarrange#1%
  {\setbox0\hbox{#1}%
   \pusharrangedpage0%
   \deadcycles\zerocount}

%D We need a couple of boxes for duplex printing \unknown

\newbox\arrangedpageA \newbox\arrangedpageB
\newbox\arrangedpageC \newbox\arrangedpageD
\newbox\arrangedpageE \newbox\arrangedpageF
\newbox\arrangedpageG \newbox\arrangedpageH

\newconditional\arrangedswapstate
\newconditional\arrangednegatestate
\newconditional\arrangedmirrorstate
\newconditional\arrangeddoublestate
\newconditional\arrangingdisabledstate
\newconditional\arrangedbackgroundstate

\def\arrangedrotationO{0}
\def\arrangedrotationE{0}

\newcount\arrangedpageN
\newcount\arrangedpageM

\newcount\arrangedpageT \arrangedpageT\plusone
\newcount\arrangedpageX \arrangedpageX\plusone
\newcount\arrangedpageY \arrangedpageY\plusone

\def\calculatepaperoffsets#1%
  {\global\paperoffset\getvalue{\??pp#1\c!offset}%
   \global\advance\paperwidth -2\dimexpr\paperoffset/\arrangedpageX\relax
   \global\advance\paperheight-2\dimexpr\paperoffset/\arrangedpageY\relax}

\def\doinstallarrangedoption#1#2%
  {\setvalue{\??pp=>#1}{#2}}

\def\doinstalledarrangedoption#1%
  {\ifcsname\??pp=>#1\endcsname
     \csname\??pp=>#1\endcsname
   \else
     \checkinstalledpagearrangement{#1}% this installs the arranger
   \fi}

\doinstallarrangedoption\empty
  {} % no default and check if empty, we can have ,,,

\doinstallarrangedoption\v!disable
  {\global\settrue\arrangingdisabledstate}

\doinstallarrangedoption\v!mirrored
  {\global\settrue\arrangedmirrorstate}

\doinstallarrangedoption\v!doublesided
  {\global\settrue\arrangeddoublestate}

\doinstallarrangedoption\v!negative
  {\global\settrue\arrangednegatestate}

\doinstallarrangedoption\v!rotated
  {\gdef\arrangedrotationO {90}%
   \gdef\arrangedrotationE{270}%
   \swapcounts\horizontalcutmarks\verticalcutmarks}

\doinstallarrangedoption{90}
  {\gdef\arrangedrotationO {90}%
   \gdef\arrangedrotationE{270}%
   \swapcounts\horizontalcutmarks\verticalcutmarks}

\doinstallarrangedoption{180}
  {\gdef\arrangedrotationO{180}%
   \gdef\arrangedrotationE  {0}}

\doinstallarrangedoption{270}
  {\gdef\arrangedrotationO{270}%
   \gdef\arrangedrotationE {90}%
   \swapcounts\horizontalcutmarks\verticalcutmarks}

\doinstallarrangedoption\s!reset
  {\global\arrangingpagesfalse}

\doinstallarrangedoption\v!background
  {\global\settrue\arrangedbackgroundstate}

\unexpanded\def\setuparranging[#1]%
  {\ifconditional\arrangingdisabledstate \else
     %global\setfalse\arrangingdisabledstate
     \global\arrangingpagestrue % will be conditional
     \global\setfalse\arrangednegatestate
     \global\setfalse\arrangedmirrorstate
     \global\setfalse\arrangeddoublestate
     \global\setfalse\arrangedswapstate
     \gdef\arrangedrotationO{0}%
     \gdef\arrangedrotationE{180}%
     \processcommalist[#1]\doinstalledarrangedoption
     \ifx\handlearrangedpage\undefined
       \global\arrangingpagesfalse
     \fi
     \setuppapersize
   \fi}

\def\installpagearrangement #1 % will lchange, no space
  {\setgvalue{\??pp\??pp#1}}

\def\checkinstalledpagearrangement#1% can be empty: aaa,,bbb
  {\executeifdefined{\??pp\??pp#1}\donothing}

\def\dosetuparrangement#1#2#3#4#5#6#7#8%
  {\global\arrangedpageX         #1%
   \global\arrangedpageY         #2%
   \global\arrangedpageT         #3%
   \global\horizontalcutmarks    #4%
   \global\verticalcutmarks      #5%
   \global\let\pusharrangedpage  #6%
   \global\let\poparrangedpages  #7%
   \global\let\handlearrangedpage#8}

\installpagearrangement {\v!normal}
  {\global\arrangingpagesfalse}

\installpagearrangement 2*16
  {\dosetuparrangement{4}{4}{16}{5}{5}%
     \pusharrangedpageTHIRTYTWO\poparrangedpagesAB\relax}

\installpagearrangement 2*8
  {\dosetuparrangement{4}{2}{8}{5}{3}%
     \pusharrangedpageSIXTEEN\poparrangedpagesAB\relax}

\installpagearrangement 2*4
  {\dosetuparrangement{2}{2}{4}{3}{3}%
     \pusharrangedpageEIGHT\poparrangedpagesAB\relax}

\installpagearrangement 2*2
  {\dosetuparrangement{2}{1}{2}{3}{2}%
     \pusharrangedpageFOURA\poparrangedpagesAB\relax}

\installpagearrangement 2**2
  {\dosetuparrangement{2}{1}{2}{3}{2}%
     \pusharrangedpageFOURB\poparrangedpagesAB\relax}

\installpagearrangement 2SIDE
  {\dosetuparrangement{2}{1}{2}{3}{2}%
     \pusharrangedpageSIDETOP\poparrangedpagesTWO\handlearrangedpageSIDE}

\installpagearrangement 2TOP
  {\dosetuparrangement{1}{2}{2}{2}{3}%
     \pusharrangedpageSIDETOP\poparrangedpagesTWO\handlearrangedpageTOP}

\installpagearrangement 2UP
  {\dosetuparrangement{2}{1}{4}{3}{2}%
     \pusharrangedpageTWO\poparrangedpagesTWO\handlearrangedpageTWOUP}

\installpagearrangement 2DOWN
  {\dosetuparrangement{1}{2}{4}{2}{3}%
     \pusharrangedpageTWO\poparrangedpagesTWO\handlearrangedpageTWODOWN}

\installpagearrangement 2*4*2 % one defined by Willy Egger:
  {\dosetuparrangement{2}{2}{4}{3}{3}%
     \pusharrangedpageSIXTEENTWO\poparrangedpagesAtoD\relax}

\installpagearrangement 2*2*4 % onother one of Willy Egger
  {\dosetuparrangement{2}{1}{8}{3}{2}%
     \pusharrangedpageSIXTEENFOUR\poparrangedpagesAtoH\relax}

\installpagearrangement 2TOPSIDE
  {\dosetuparrangement{1}{2}{4}{2}{3}%
     \pusharrangedpageTWOTOPSIDE\poparrangedpagesTWOTOPSIDE\handlearrangedpageTOP}

\def\filluparrangedpages % beware: \realpageno is 1 ahead
  {\ifarrangingpages
     \scratchcounter\numexpr\realpageno-\plusone\relax
     \dosetmodulo\scratchcounter\arrangedpageT\scratchcounter
     \ifcase\scratchcounter\else
       \advance\scratchcounter \plusone
       \dostepwiserecurse\scratchcounter\arrangedpageT\plusone
         {\noheaderandfooterlines\ejectdummypage}%
     \fi
   \fi}

\def\handlearrangedpageXandY#1#2#3#4#5%
  {\global\setbox#5\hbox to \arrangedpageX\paperwidth
     {\setbox\scratchbox\vbox to \arrangedpageY\paperheight
        {\offinterlineskip
         \vskip#4\paperheight
         \hskip#3\paperwidth
         \dorotatebox{\ifcase#2 0\else180\fi}\hbox{\box#1}%
         \vfill}%
      \wd\scratchbox\zeropoint
      \box\scratchbox\box#5\hss}}

\def\gotonextarrangepage
  {\global\advance\arrangeno \plusone
   \def\pagecutmarksymbol{\the\arrangeno}}

\def\outputarrangedbox#1%
  {\bgroup
   \forgetall % somehow we're back and need to redo this
   \gotonextarrangepage
   \ifnum\arrangedrotationO\arrangedrotationE>\zerocount
     \setbox#1\vbox
       {\ifconditional\arrangeddoublestate
          \ifodd\arrangeno
            \dorotatebox\arrangedrotationO\hbox{\box#1}%
          \else
            \dorotatebox\arrangedrotationE\hbox{\box#1}%
          \fi
        \else
          \dorotatebox\arrangedrotationO\hbox{\box#1}%
        \fi}%
   \fi
   \ifconditional\arrangedmirrorstate
     \setbox#1\vbox{\domirrorbox\vbox{\box#1}}%
   \fi
   \ifconditional\arrangednegatestate
     \negatecolorbox{#1}%
   \fi
   \finishpagebox#1%
   \ifconditional\arrangedbackgroundstate\addprintbackground#1\fi
   \actualshipout{\box#1}%
   \egroup}

%D The format file can be 16K smaller when we postpone the
%D real arrangments. Some day ...

\def\reportarrangedpage#1%
  {\showmessage\m!system{23}{\the\realpageno.\the\pageno\ifnum\subpageno>0 .\the\subpageno\fi,\number#1}}

% TOP

% 32/16/8/4/SIDE

\def\poparrangedpagesAB
  {\ifnum\arrangedpageN>\zerocount
     \paperwidth\arrangedpageX\paperwidth
     \paperheight\arrangedpageY\paperheight
     \outputarrangedbox\arrangedpageA
     \outputarrangedbox\arrangedpageB
     \global\arrangedpageN\zerocount
   \fi}

\def\pusharrangedpageTHIRTYTWO#1% taco's challenge
  {\global\advance\arrangedpageN\plusone
   \reportarrangedpage\arrangedpageN
   \ifcase\arrangedpageN
   \or \handlearrangedpageXandY{#1}033\arrangedpageA %  1
   \or \handlearrangedpageXandY{#1}003\arrangedpageB %  2
   \or \handlearrangedpageXandY{#1}100\arrangedpageB %  3
   \or \handlearrangedpageXandY{#1}130\arrangedpageA %  4
   \or \handlearrangedpageXandY{#1}100\arrangedpageA %  5
   \or \handlearrangedpageXandY{#1}130\arrangedpageB %  6
   \or \handlearrangedpageXandY{#1}033\arrangedpageB %  7
   \or \handlearrangedpageXandY{#1}003\arrangedpageA %  8
   \or \handlearrangedpageXandY{#1}102\arrangedpageA %  9
   \or \handlearrangedpageXandY{#1}132\arrangedpageB % 10
   \or \handlearrangedpageXandY{#1}031\arrangedpageB % 11
   \or \handlearrangedpageXandY{#1}001\arrangedpageA % 12
   \or \handlearrangedpageXandY{#1}031\arrangedpageA % 13
   \or \handlearrangedpageXandY{#1}001\arrangedpageB % 14
   \or \handlearrangedpageXandY{#1}102\arrangedpageB % 15
   \or \handlearrangedpageXandY{#1}132\arrangedpageA % 16
   \or \handlearrangedpageXandY{#1}122\arrangedpageA % 17
   \or \handlearrangedpageXandY{#1}112\arrangedpageB % 18
   \or \handlearrangedpageXandY{#1}011\arrangedpageB % 19
   \or \handlearrangedpageXandY{#1}021\arrangedpageA % 20
   \or \handlearrangedpageXandY{#1}011\arrangedpageA % 21
   \or \handlearrangedpageXandY{#1}021\arrangedpageB % 22
   \or \handlearrangedpageXandY{#1}122\arrangedpageB % 23
   \or \handlearrangedpageXandY{#1}112\arrangedpageA % 24
   \or \handlearrangedpageXandY{#1}013\arrangedpageA % 25
   \or \handlearrangedpageXandY{#1}023\arrangedpageB % 26
   \or \handlearrangedpageXandY{#1}120\arrangedpageB % 27
   \or \handlearrangedpageXandY{#1}110\arrangedpageA % 28
   \or \handlearrangedpageXandY{#1}120\arrangedpageA % 29
   \or \handlearrangedpageXandY{#1}110\arrangedpageB % 30
   \or \handlearrangedpageXandY{#1}013\arrangedpageB % 31
   \or \handlearrangedpageXandY{#1}023\arrangedpageA % 32
     \poparrangedpages
   \fi}

\def\pusharrangedpageSIXTEEN#1% changed to match the official way of doing
  {\global\advance\arrangedpageN\plusone
   \reportarrangedpage\arrangedpageN
   \ifcase\arrangedpageN
   \or \handlearrangedpageXandY{#1}031\arrangedpageA %  1
   \or \handlearrangedpageXandY{#1}001\arrangedpageB %  2
   \or \handlearrangedpageXandY{#1}031\arrangedpageB %  3
   \or \handlearrangedpageXandY{#1}001\arrangedpageA %  4
   \or \handlearrangedpageXandY{#1}100\arrangedpageA %  5
   \or \handlearrangedpageXandY{#1}130\arrangedpageB %  6
   \or \handlearrangedpageXandY{#1}100\arrangedpageB %  7
   \or \handlearrangedpageXandY{#1}130\arrangedpageA %  8
   \or \handlearrangedpageXandY{#1}120\arrangedpageA %  9
   \or \handlearrangedpageXandY{#1}110\arrangedpageB % 10
   \or \handlearrangedpageXandY{#1}120\arrangedpageB % 11
   \or \handlearrangedpageXandY{#1}110\arrangedpageA % 12
   \or \handlearrangedpageXandY{#1}011\arrangedpageA % 13
   \or \handlearrangedpageXandY{#1}021\arrangedpageB % 14
   \or \handlearrangedpageXandY{#1}011\arrangedpageB % 15
   \or \handlearrangedpageXandY{#1}021\arrangedpageA % 16
     \poparrangedpages
   \fi}

\def\pusharrangedpageEIGHT#1% changed to match the official way of doing
  {\global\advance\arrangedpageN\plusone
   \reportarrangedpage\arrangedpageN
   \ifcase\arrangedpageN
   \or \handlearrangedpageXandY{#1}011\arrangedpageA %  1
   \or \handlearrangedpageXandY{#1}001\arrangedpageB %  2
   \or \handlearrangedpageXandY{#1}100\arrangedpageB %  3
   \or \handlearrangedpageXandY{#1}110\arrangedpageA %  4
   \or \handlearrangedpageXandY{#1}100\arrangedpageA %  5
   \or \handlearrangedpageXandY{#1}110\arrangedpageB %  6
   \or \handlearrangedpageXandY{#1}011\arrangedpageB %  7
   \or \handlearrangedpageXandY{#1}001\arrangedpageA %  8
     \poparrangedpages
   \fi}

\def\pusharrangedpageFOURA{\pusharrangedpageFOURdo01}
\def\pusharrangedpageFOURB{\pusharrangedpageFOURdo10}

\def\pusharrangedpageFOURdo#1#2#3%
  {\global\advance\arrangedpageN\plusone
   \reportarrangedpage\arrangedpageN
   \ifcase\arrangedpageN
   \or \handlearrangedpageXandY{#3}010\arrangedpageA    %  1
   \or \handlearrangedpageXandY{#3}0{#1}0\arrangedpageB %  2/3 not {1}
   \or \handlearrangedpageXandY{#3}0{#2}0\arrangedpageB %  3/2 not {1}
   \or \handlearrangedpageXandY{#3}000\arrangedpageA    %  4
     \poparrangedpages
   \fi}

\def\pusharrangedpageSIDETOP#1%
  {\global\advance\arrangedpageN\plusone
   \reportarrangedpage\arrangedpageN
   \ifcase\arrangedpageN
   \or \handlearrangedpageXandY{#1}000\arrangedpageA %  1
   \or \handlearrangedpageXandY{#1}000\arrangedpageB %  2
     \poparrangedpages
   \fi}

\def\handlearrangedpageSIDE
  {\global\wd\arrangedpageA\paperwidth
   \global\wd\arrangedpageB\paperwidth
   \global\setbox\arrangedpageA\hbox
     {\box\arrangedpageA\box\arrangedpageB}%
   \global\ht\arrangedpageA\paperheight}

\def\handlearrangedpageTOP
  {\global\ht\arrangedpageA\paperheight
   \global\ht\arrangedpageB\paperheight
   \global\setbox\arrangedpageA\vbox
     {\offinterlineskip\vskip\paperheight
      \box\arrangedpageA\box\arrangedpageB}%
   \global\setbox\arrangedpageB\box\scratchbox} % ?

% 2UP/2DOWN / 1pt prevents overflow

\def\splitoffarrangedpagesTWO
  {\splittopskip\zeropoint
   \global\setbox\arrangedpageA\vsplit\arrangedpageB to \onepoint
   \scratchdimen\dimexpr\ht\arrangedpageB-\onepoint\relax
   \ifdim\scratchdimen>\onepoint
     \setbox\scratchbox\vsplit\arrangedpageB to \scratchdimen
   \fi}

\def\handlearrangedpageTWOUP
  {\splitoffarrangedpagesTWO
   \ifconditional\arrangedswapstate
     \global\setbox\arrangedpageA\hbox
       {\clippedprintbox\zerocount\arrangedpageA
        \clippedprintbox\plusone  \arrangedpageB}%
     \setfalse\arrangedswapstate
   \else
     \global\setbox\arrangedpageA\hbox
       {\clippedprintbox\zerocount\arrangedpageB
        \clippedprintbox\plusone  \arrangedpageA}%
     \settrue\arrangedswapstate
   \fi
   \global\ht\arrangedpageA\paperheight
   \global\setbox\arrangedpageB\box\scratchbox}

\def\handlearrangedpageTWODOWN
  {\splitoffarrangedpagesTWO
   \global\ht\arrangedpageA\paperheight
   \global\ht\arrangedpageB\paperheight
   \ifconditional\arrangedswapstate
     \global\setbox\arrangedpageA\vbox
       {\offinterlineskip\vskip\paperheight
        \box\arrangedpageA\box\arrangedpageB}%
     \setfalse\arrangedswapstate
   \else
     \global\setbox\arrangedpageA\vbox
       {\offinterlineskip\vskip\paperheight
        \box\arrangedpageB\box\arrangedpageA}%
     \settrue\arrangedswapstate
   \fi
   \global\setbox\arrangedpageB\box\scratchbox}

\def\poparrangedpagesTWO
  {\ifnum\arrangedpageN>\zerocount
     \setfalse\arrangedswapstate
     \doloop
       {\handlearrangedpage
        \bgroup
        \paperwidth \arrangedpageX\paperwidth
        \paperheight\arrangedpageY\paperheight
        \ht\arrangedpageA\paperheight
        \wd\arrangedpageA\paperwidth
        \outputarrangedbox\arrangedpageA
        \egroup
        \ifdim\ht\arrangedpageB=\zeropoint
          \exitloop
        \fi}%
     \global\arrangedpageN\zerocount
   \fi}

\def\pusharrangedpageTWO#1%
  {\global\advance\arrangedpageN\plusone
   \reportarrangedpage\arrangedpageN
   \global\setbox\arrangedpageB\vbox
     {\offinterlineskip
      \unvbox\arrangedpageB
      \allowbreak
      \ht#1\onepoint
      \dp#1\zeropoint
      \vbox{\box#1}}}

\def\poparrangedpagesTWOTOPSIDE
  {\ifnum\arrangedpageN>\zerocount
     \bgroup
     \global\arrangedpageN\plustwo
     \poparrangedpagesTWO
     \let\arrangedpageA\arrangedpageC
     \let\arrangedpageB\arrangedpageD
     \global\arrangedpageN\plustwo
     \poparrangedpagesTWO
     \global\arrangedpageN\zerocount
     \egroup
  \fi}

\def\pusharrangedpageTWOTOPSIDE#1%
  {\global\advance\arrangedpageN\plusone
   \reportarrangedpage\arrangedpageN
   \ifcase\arrangedpageN
   \or \handlearrangedpageXandY{#1}000\arrangedpageA %  1
   \or \handlearrangedpageXandY{#1}000\arrangedpageC %  2
   \or \handlearrangedpageXandY{#1}000\arrangedpageB %  1
   \or \handlearrangedpageXandY{#1}000\arrangedpageD %  2
     \poparrangedpages
   \fi}

%D Willy Egger's sheet simulations:

\def\poparrangedpagesAtoH
  {\ifnum\arrangedpageN>\zerocount
     \paperwidth \arrangedpageX\paperwidth
     \paperheight\arrangedpageY\paperheight
     \outputarrangedbox\arrangedpageA
     \outputarrangedbox\arrangedpageB
     \outputarrangedbox\arrangedpageC
     \outputarrangedbox\arrangedpageD
     \outputarrangedbox\arrangedpageE
     \outputarrangedbox\arrangedpageF
     \outputarrangedbox\arrangedpageG
     \outputarrangedbox\arrangedpageH
     \global\arrangedpageN\zerocount
   \fi}

% to arrange 16 pages on 2 sheets to form one booklet

\def\poparrangedpagesAtoD
  {\ifnum\arrangedpageN>\zerocount
     \paperwidth\arrangedpageX\paperwidth
     \paperheight\arrangedpageY\paperheight
     \outputarrangedbox\arrangedpageA
     \outputarrangedbox\arrangedpageB
     \outputarrangedbox\arrangedpageC
     \outputarrangedbox\arrangedpageD
     \global\arrangedpageN\zerocount
   \fi}

% to arrange 16 pages on 4 sheets to form one booklet

\def\pusharrangedpageSIXTEENFOUR#1%
  {\global\advance\arrangedpageN\plusone
   \reportarrangedpage\arrangedpageN
   \ifcase\arrangedpageN
   \or \handlearrangedpageXandY{#1}010\arrangedpageA %  1
   \or \handlearrangedpageXandY{#1}000\arrangedpageB %  2
   \or \handlearrangedpageXandY{#1}010\arrangedpageC %  3
   \or \handlearrangedpageXandY{#1}000\arrangedpageD %  4
   \or \handlearrangedpageXandY{#1}010\arrangedpageE %  5
   \or \handlearrangedpageXandY{#1}000\arrangedpageF %  6
   \or \handlearrangedpageXandY{#1}010\arrangedpageG %  7
   \or \handlearrangedpageXandY{#1}000\arrangedpageH %  8
   \or \handlearrangedpageXandY{#1}010\arrangedpageH %  9
   \or \handlearrangedpageXandY{#1}000\arrangedpageG % 10
   \or \handlearrangedpageXandY{#1}010\arrangedpageF % 11
   \or \handlearrangedpageXandY{#1}000\arrangedpageE % 12
   \or \handlearrangedpageXandY{#1}010\arrangedpageD % 13
   \or \handlearrangedpageXandY{#1}000\arrangedpageC % 14
   \or \handlearrangedpageXandY{#1}010\arrangedpageB % 15
   \or \handlearrangedpageXandY{#1}000\arrangedpageA % 16
     \poparrangedpages
   \fi}

% to arrange 16 pages on 2 sheets to form one booklet

\def\pusharrangedpageSIXTEENTWO#1%
  {\global\advance\arrangedpageN\plusone
   \reportarrangedpage\arrangedpageN
   \ifcase\arrangedpageN
   \or \handlearrangedpageXandY{#1}011\arrangedpageA %  1
   \or \handlearrangedpageXandY{#1}001\arrangedpageB %  2
   \or \handlearrangedpageXandY{#1}011\arrangedpageC %  3
   \or \handlearrangedpageXandY{#1}001\arrangedpageD %  4
   \or \handlearrangedpageXandY{#1}100\arrangedpageD %  5
   \or \handlearrangedpageXandY{#1}110\arrangedpageC %  6
   \or \handlearrangedpageXandY{#1}100\arrangedpageB %  7
   \or \handlearrangedpageXandY{#1}110\arrangedpageA %  8
   \or \handlearrangedpageXandY{#1}100\arrangedpageA %  9
   \or \handlearrangedpageXandY{#1}110\arrangedpageB % 10
   \or \handlearrangedpageXandY{#1}100\arrangedpageC % 11
   \or \handlearrangedpageXandY{#1}110\arrangedpageD % 12
   \or \handlearrangedpageXandY{#1}011\arrangedpageD % 13
   \or \handlearrangedpageXandY{#1}001\arrangedpageC % 14
   \or \handlearrangedpageXandY{#1}011\arrangedpageB % 15
   \or \handlearrangedpageXandY{#1}001\arrangedpageA % 16
     \poparrangedpages
   \fi}

% % handy for stickers etc, this way we can treat them as page
%
% \setuppapersize [XY][A4]
% \setuppaper     [topspace=5mm,backspace=5mm,dx=1mm,dy=1mm,nx=2,ny=6]
% \setuplayout    [page] [topspace=5mm,backspace=5mm]
% \setuplayout    [page]
% \setuplayout    [location=middle]
% \setuparranging [XY]
% \showframe
%
% \starttext \dorecurse{30}{test \recurselevel \page} \stoptext

\def\pusharrangedpageXY#1%
  {\global\advance\arrangedpageN\plusone
   \global\advance\arrangedpageM\plusone
   \reportarrangedpage\arrangedpageN
   \global\setbox\arrangedpageB\hbox \ifdim\@@ppwidth>\zeropoint to \@@ppwidth \fi
      {\ifvoid\arrangedpageB\else
         \unhbox\arrangedpageB
         \ifdim\@@ppdx>\zeropoint \else \hss\fi
         \hskip\@@ppdx
         \ifdim\@@ppdx>\zeropoint \else \hss\fi
       \fi
       \box#1}%
    \ifnum\arrangedpageM<\arrangedpageX\else
      \global\setbox\arrangedpageA\vbox \ifdim\@@ppheight>\zeropoint to \@@ppheight \fi
        {\offinterlineskip
         \ifvoid\arrangedpageA\else
           \unvbox\arrangedpageA
           \ifdim\@@ppdy>\zeropoint \else \vss\fi
           \vskip\@@ppdy
           \ifdim\@@ppdy>\zeropoint \else \vss\fi
         \fi
         \box\arrangedpageB}%
      \global\arrangedpageM\zerocount
    \fi
    \ifnum\arrangedpageN<\arrangedpageT\else
      \poparrangedpages
    \fi}

\def\poparrangedpagesXY
  {\ifnum\arrangedpageN>\zerocount
     \paperwidth \arrangedpageX\paperwidth
     \paperheight\arrangedpageY\paperheight
     \outputarrangedbox\arrangedpageA
     \global\arrangedpageN\zerocount
     \global\arrangedpageM\zerocount
   \fi}

\installpagearrangement XY
  {\dosetuparrangement\@@ppnx\@@ppny\@@ppxy\!!zerocount\!!zerocount
     \pusharrangedpageXY\poparrangedpagesXY\relax}

%D A crazy definition, don't guess who pushed me for the landscape option.

\definepapersize
  [XY]
  [\c!height=\dimexpr\dimexpr\@@ppheight-\numexpr\@@ppny-1\relax\dimexpr\@@ppdy\relax\relax/\@@ppny\relax,
   \c!width =\dimexpr\dimexpr\@@ppwidth -\numexpr\@@ppnx-1\relax\dimexpr\@@ppdx\relax\relax/\@@ppnx\relax]

\setuppaper
  [\c!width =\dimexpr\printpaperwidth -2\dimexpr\@@ppbackspace\relax\relax,
   \c!height=\dimexpr\printpaperheight-2\dimexpr\@@pptopspace \relax\relax]

% \definepageshift[test][horizontal][10pt,20pt,30pt,40pt,50pt]
% \definepageshift[test][vertical]  [10pt,20pt,30pt,40pt,50pt]
%
% \setuppageshift[test]
% \setuppageshift[test][test]
% \setuppageshift[test][none]
% \setuppageshift[none][test]
% \setuppageshift[paper][test][test] % arrange only
% \setuppageshift[paper][test]       % arrange only
% \setuppageshift[print][test][test]
%
% \showframe \dorecurse{100}{\input tufte \par}

% #1=name #2=horizontal|vertical #3=shiftlist

\unexpanded\def\definepageshift
  {\dotripleargument\dodefinepageshift}

\def\dodefinepageshift[#1][#2][#3]%
  {\setvalue{\??pt#2:#1}{#3}}

\letempty\hpageshifts \newcount\nofhpageshifts
\letempty\vpageshifts \newcount\nofvpageshifts

\def\dogetpageshift#1#2#3% #1=\dimenx #2=\xpageshifts #3=\nofxpageshifts
  {\ifx#2\empty          % we could do this in lua
     #1\zeropoint
   \else
     \global\advance#3\plusone
     \getfromcommacommand[#2][#3]%
     \ifx\commalistelement\empty
       \global#3\plusone % we cycle
       \getfromcommacommand[#2][#3]%
     \fi
     \ifx\commalistelement\empty
       #1\zeropoint
     \else
       #1=\commalistelement
       \donetrue
     \fi
   \fi}

\def\shiftpagebox#1%
  {\donefalse
   \dogetpageshift{\dimen0}\hpageshifts\nofhpageshifts
   \dogetpageshift{\dimen2}\vpageshifts\nofvpageshifts
   \ifdone % see also layout offsets, maybe \movebox
     \edef\next{\wd#1\the\wd#1\ht#1\the\ht#1\dp#1\the\dp#1}%
     \setbox#1\vbox
       {\offinterlineskip\vskip\dimen2\hskip\dimen0\box#1}%
     \next
   \fi}

\unexpanded\def\setuppageshift
  {\dotripleempty\dosetuppageshift}

\def\dosetuppageshift[#1][#2][#3]% page|paper horizontal vertical
  {\ifthirdargument              % paper=arrange
     \edef\hpageshifts{\ifcsname\??pt\v!horizontal:#2\endcsname\csname\??pt\v!horizontal:#2\endcsname}%
     \edef\vpageshifts{\ifcsname\??pt\v!vertical  :#3\endcsname\csname\??pt\v!vertical  :#3\endcsname}%
     \doifelse{#1}\v!page {\let\shiftprintpagebox\shiftpagebox}{\let\shiftprintpagebox\gobbleoneargument}%
     \doifelse{#1}\v!paper{\let\shiftpaperpagebox\shiftpagebox}{\let\shiftpaperpagebox\gobbleoneargument}%
   \else\ifsecondargument
     \doifinsetelse{#1}{\v!page,\v!paper}
       {\setuppageshift[#1][#2][#2]}
       {\setuppageshift[\v!page][#1][#2]}%
   \else\iffirstargument
     \setuppageshift[\v!page][#1][#1]%
   \fi\fi\fi}


\protect \endinput