%D \module
%D   [       file=page-sel, % moved from page-imp
%D        version=1998.01.15,
%D          title=\CONTEXT\ Page Macros,
%D       subtitle=Page Selection,
%D         author=Hans Hagen,
%D           date=\currentdate,
%D      copyright={PRAGMA ADE \& \CONTEXT\ Development Team}]
%C
%C This module is part of the \CONTEXT\ macro||package and is
%C therefore copyrighted by \PRAGMA. See mreadme.pdf for
%C details.

%D This will become runtime loaded code.

\writestatus{loading}{ConTeXt Page Macros / Page Selection}

\unprotect

%D One can (mis)use this mechanism, in close cooperation
%D with \PDFTEX\ to arrange pages of already produced files.
%D
%D \starttyping
%D \insertpages[file.pdf][1,3][n=30,width=18cm]
%D \stoptyping
%D
%D The pages are inserted in the text area, and even pages
%D are repositioned according to the width. In this example
%D empty pages are added after page 1 and 3.
%D
%D Selecting pages can be accomplished by:
%D
%D \starttyping
%D \filterpages[file.pdf][1,3,5][n=30,width=18cm]
%D \stoptyping
%D
%D One may pass \type {odd} or \type {even} instead of a
%D comma separated list. A third alternative is:
%D
%D \starttyping
%D \copypages[file.pdf][n=30,scale=950]
%D \stoptyping
%D
%D This macros inserts the page, according to the settings
%D provided.

\def\insertpages
  {\dotripleempty\doinsertpages}

\def\doinsertpages[#1][#2][#3]%
  {\doifassignmentelse{#2}
     {\dodoinsertpages[#1][][#2]}
     {\dodoinsertpages[#1][#2][#3]}}

\def\dodoinsertpages[#1][#2][#3]%
  {\bgroup
   \dontcomplain
   \getfiguredimensions[#1]%
   \getparameters[\??ip][\c!n=\noffigurepages,\c!width=\!!zeropoint,#3]%
   \doifinset0{#2}{\emptyhbox\page}%
   \dorecurse\@@ipn
     {\dofilterpage{#1}\recurselevel
      \doifinset\recurselevel{#2}{\emptyhbox\page}}%
   \egroup}

\def\filterpages
  {\dotripleempty\dofilterpages}

\def\dofilterpages[#1][#2][#3]% % \noffigurepages not yet supported
  {\bgroup
   \dontcomplain
   \getfiguredimensions[#1]%
   \getparameters[\??ip][\c!n=\noffigurepages,\c!width=\!!zeropoint,#3]%
   \doifelse{#2}\v!even
     {\dorecurse\@@ipn
        {\ifodd\recurselevel\relax\else\dofilterpage{#1}\recurselevel\fi}}
     {\doifelse{#2}\v!odd
        {\dorecurse\@@ipn
           {\ifodd\recurselevel\relax\dofilterpage{#1}\recurselevel\fi}}
        {\def\dodocommand##1{\ifnum##1>\@@ipn\else\dofilterpage{#1}{##1}\fi}%
         \def\docommand  ##1{\dowithrange{##1}\dodocommand}%
         \processcommalist[#2]\docommand}}%
   \egroup}

\def\dofilterpage#1#2%
  {\hbox to \textwidth
     {\ifdoublesided\ifdim\@@ipwidth>\zeropoint\relax\ifodd\realpageno\else
        \hfill
        \def\dowithfigure{\hskip-\@@ipwidth}%
      \fi\fi\fi
      \setbox0\hbox
        {\externalfigure[#1][\c!page=#2,\c!height=\textheight]}%
      \wd0\zeropoint
      \box0}
   \page}

\def\copypages
  {\dodoubleempty\docopypages}

\def\docopypages[#1][#2]%
  {\bgroup
   \getfiguredimensions[#1]%
   \getparameters[\??ip]
     [\c!n=\noffigurepages,
      \c!marking=\v!off,
      \c!scale=\!!thousand,
      \c!offset=\!!zeropoint,
      #2]%
   \dorecurse\@@ipn
     {\vbox to \textheight
        {\hsize\textwidth
         \scratchdimen\@@ipoffset
         \centeredbox
           {\doifelse\@@ipmarking\v!on\cuthbox\hbox
              {\ifdim\scratchdimen>\zeropoint\relax
                 \advance\vsize -2\scratchdimen
                 \advance\hsize -2\scratchdimen
                 \externalfigure[#1][\c!page=\recurselevel,#2,\c!scale=,\c!factor=\v!max,\c!offset=\v!overlay]%
               \else
                 \externalfigure[#1][\c!page=\recurselevel,#2,\c!offset=\v!overlay]%
               \fi}}}
      \page}
   \egroup}

%D \macros
%D   {combinepages}
%D
%D Yet another way of postprocessing is handles by \type
%D {\combinepages}. This macro builds a matrix of pages from a
%D file, for example:
%D
%D \starttyping
%D \setuppapersize
%D   [A4][A4] % or [A4,landscape][A4,landscape]
%D
%D \setuplayout
%D   [header=0pt,footer=1cm,
%D    backspace=1cm,topspace=1cm,
%D    width=middle,height=middle]
%D
%D \setupfootertexts
%D   [presentation---\currentdate\space---\space\pagenumber]
%D
%D \starttext
%D   \combinepages[slides][nx=2,ny=3,frame=on]
%D \stoptext
%D \stoptyping
%D
%D One can influence the way the pages are combined. (This
%D will be explained some time.)

\def\combinepages
  {\dodoubleempty\docombinepages}

\def\docombinepages[#1][#2]% a=perpag b=free
  {\bgroup
   \dontcomplain
   \getfiguredimensions[#1]%
   \getparameters
     [\??ip]
     [\c!alternative=\v!a,
      \c!n=\noffigurepages,\c!nx=2,\c!ny=2,\c!start=1,\c!stop=\!!maxcard,
      \c!distance=\bodyfontsize,
      \c!bottom=\vfill,\c!top=\vss,
      \c!left=\hss,\c!right=\hss,
      \c!before=\page,\c!after=\page,\c!inbetween=\blank,
      \c!frame=,\c!background=,\c!backgroundcolor=,
      #2]%
   \def\@@ipname{#1}%
   \@@ipbefore
   \expandcheckedcsname{\??ip::\c!alternative:}\@@ipalternative\v!b
   \@@ipafter
   \egroup}

\setvalue{\??ip::\c!alternative:\v!a}%
  {\global\combinedpagescounter\@@ipstart
   \doloop
     {\vbox to \textheight
        {\hsize\textwidth % ? ?
         \scratchdimen\@@ipdistance
         \!!widtha \dimexpr(\hsize-\@@ipnx\scratchdimen+\scratchdimen)/\@@ipnx\relax
         \!!heighta\dimexpr(\vsize-\@@ipny\scratchdimen+\scratchdimen)/\@@ipny\relax
         \dorecurse\@@ipny
           {\hbox to \hsize
              {\dorecurse\@@ipnx
                 {\vbox to \!!heighta
                    {\hsize\!!widtha
                     \vsize\!!heighta
                     \@@iptop
                     \hbox to \hsize
                       {\@@ipleft
                        \ifnum\combinedpagescounter>\@@ipstop\relax
                          \globallet\@@ipn\!!zerocount
                        \else\ifnum\combinedpagescounter>\@@ipn \else
                          \externalfigure[\@@ipname]
                            [\c!object=\v!no,
                             \c!page=\number\combinedpagescounter,
                             \c!factor=\v!max,
                             \c!background=\@@ipbackground,
                             \c!backgroundcolor=\@@ipbackgroundcolor,
                             \c!frame=\@@ipframe]%
                        \fi\fi
                        \@@ipright}
                     \@@ipbottom}%
                  \global\advance\combinedpagescounter\plusone
                  \hfil}%
               \hfilneg}
            \vfil}%
         \vfilneg}%
         \page
         \ifnum\combinedpagescounter>\@@ipn \exitloop\fi}}

\setvalue{\??ip::\c!alternative:\v!c}%
  {\global\combinedpagescounter\@@ipstart
   \doloop
     {\vbox to \textheight
        {\hsize\textwidth % ? ?
         \scratchdimen\@@ipdistance
         \!!widtha \dimexpr(\hsize-\@@ipnx\scratchdimen+\scratchdimen)/\@@ipnx\relax
         \!!heighta\dimexpr(\vsize-\@@ipny\scratchdimen+\scratchdimen)/\@@ipny\relax
         \hbox to \hsize
           {\dorecurse\@@ipnx
              {\@@ipleft
               \vbox to \textheight
                 {\hsize\!!widtha
                    {\dorecurse\@@ipny
                       {\@@iptop
                        \hbox to \hsize
                          {\vbox to \!!heighta
                             {\hsize\!!widtha
                              \vsize\!!heighta
                              \ifnum\combinedpagescounter>\@@ipstop\relax
                                \globallet\@@ipn\!!zerocount
                              \else\ifnum\combinedpagescounter>\@@ipn \else
                                \externalfigure[\@@ipname]
                                  [\c!object=\v!no,
                                   \c!page=\number\combinedpagescounter,
                                   \c!factor=\v!max,
                                   \c!background=\@@ipbackground,
                                   \c!backgroundcolor=\@@ipbackgroundcolor,
                                   \c!frame=\@@ipframe]%
                              \fi\fi}}
                         \global\advance\combinedpagescounter\plusone
                         \@@ipbottom}%
                      \vfil}%
                   \vfilneg}
                \hfil}%
            \hfilneg}}
         \page
         \ifnum\combinedpagescounter>\@@ipn \exitloop\fi}}

\setvalue{\??ip::\c!alternative:\v!horizontal}{\getvalue{\??ip::\c!alternative:\v!a}}
\setvalue{\??ip::\c!alternative:\v!vertical  }{\getvalue{\??ip::\c!alternative:\v!c}}

\setvalue{\??ip::\c!alternative:\v!b}%
  {\global\combinedpagescounter\@@ipstart
   \doloop
     {\startbaselinecorrection
        \scratchdimen\@@ipdistance
        \!!widtha\dimexpr(\hsize-\@@ipnx\scratchdimen+\scratchdimen)/\@@ipnx\relax
        \hbox to \hsize
          {\dorecurse\@@ipnx
             {\global\advance\combinedpagescounter\plusone
              \ifnum\combinedpagescounter>\@@ipn \else
                 \normalexpanded{\noexpand\externalfigure[\@@ipname]
                   [\c!page=\number\combinedpagescounter,
                    \c!width=\the\!!widtha,% todo \freezedimenmacro
                    \c!background=\@@ipbackground,
                    \c!backgroundcolor=\@@ipbackgroundcolor,
                    \c!frame=\@@ipframe]}%
                 \hfill
              \fi}\hfillneg}%
      \stopbaselinecorrection
      \ifnum\combinedpagescounter<\@@ipn\relax
        \@@ipinbetween
      \else
        \exitloop
      \fi}}

% This macro cuts a page into n parts that can be pasted
% together.

\def\slicepages
  {\dotripleempty\doslicepages}

\def\doslicepages[#1][#2][#3]%
  {\ifthirdargument
     \dodoslicepages[#1][#2][#3]%
   \else
     \dodoslicepages[#1][#2][#2]%
   \fi}

\newcounter\slicedpagenumber

\def\dodoslicepages[#1][#2][#3]%
  {\bgroup
   \dontcomplain
   \globallet\slicedpagenumber\!!zerocount
   \getfiguredimensions[#1]
   \getparameters
     [\??ip]
     [\c!n=1,
      \c!offset=\!!zeropoint,
      \c!hoffset=\!!zeropoint,\c!voffset=\!!zeropoint,
      \c!width=\figurewidth,\c!height=\figureheight,#2]
   \ifnum\@@ipn>\zerocount
     \definepapersize
       [\s!dummy][\c!height=\@@ipheight,\c!width=\@@ipwidth]
     \setuppapersize
       [\s!dummy][\s!dummy]
     \setuplayout
       [\c!backspace=\!!zeropoint,\c!topspace=\!!zeropoint,
        \c!height=\v!middle,\c!width=\v!middle,
        \c!textdistance=\!!zeropoint,
        \c!header=\!!zeropoint,\c!footer=\!!zeropoint]
   \fi
   \dorecurse\noffigurepages
     {\global\let\slicedpagenumber\recurselevel
      \ifnum\@@ipn>\plusone
        \dorecurse\@@ipn
          {\let\xslice\recurselevel
           \dorecurse\@@ipn
             {\let\yslice\recurselevel
              \clip
                [\c!nx=\@@ipn,\c!ny=\@@ipn,\c!x=\xslice,\c!y=\yslice]
                {\scale
                   [\c!scale=\@@ipn000]
                   {\externalfigure[#1][\c!page=\slicedpagenumber]}}
              \page}}
      \else
        \ifodd\slicedpagenumber\relax
          \getparameters[\??ip][#2]
        \else
          \getparameters[\??ip][#3]
        \fi
        \hskip\@@ipoffset
        \clip
          [\c!hoffset=\@@iphoffset,\c!voffset=\@@ipvoffset,
           \c!height=\@@ipheight,\c!width=\@@ipwidth]
          {\externalfigure[#1][\c!page=\slicedpagenumber]}
        \page
      \fi}
   \egroup}

% \starttext \slicepages[slice1.pdf][n=3] \stoptext

\protect \endinput