%D \module
%D   [       file=anch-snc,
%D        version=2003.12.01, % actually 1999 so real old
%D          title=\CONTEXT\ Anchoring Macros,
%D       subtitle=Synchronization,
%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 The original is in the mkii file. It does more at the \TEX\ end and
%D has some more magic. If we really need that I'll add it. After all,
%D in mkiv we can do things different.

%D TODO: bleed : + left , minus right oro check if it touches page ... autobleed

\writestatus{loading}{ConTeXt Anchoring Macros / Synchronization}

\registerctxluafile{anch-snc}{}

\unprotect

\ifx\??syncposcounter\undefined \installcorenamespace{syncposcounter} \fi
\ifx\s!syncpos       \undefined \def\s!syncpos       {syncpos}        \fi

\let\c_sync_n\relax

\unexpanded\def\definesyncpositions[#1]%
  {\ifcsname\??syncposcounter:#1\endcsname \else
     \expandafter\newcount\csname\??syncposcounter:#1\endcsname
   \fi}

\unexpanded\def\syncposition
  {\dodoubleempty\anch_sync_position}

\def\anch_sync_position[#1][#2]% we could actually use par positions
  {\dontleavehmode
   \ifcsname\??syncposcounter:#1\endcsname
     \let\c_sync_n\lastnamedcs
     \global\advance\c_sync_n\plusone
     \enabletextarearegistration
     \setpositionplus{\s!syncpos:#1:\the\c_sync_n}{#2}\hpack{\strut}%
   \else
     \strut
   \fi
   \ignorespaces}

\protect

\continueifinputfile{anch-snc.mkiv}

\starttext

% \setuppapersize[A4][A3]

\setuplayout[location=middle]

\setupbodyfont[dejavu]

\definesyncpositions[1]
\definesyncpositions[2]

% \enabletrackers[metapost.lua]

\startMPdefinitions
    input "mp-asnc.mpiv" ;

    SetSyncColor(1,0,"magenta") ;
    SetSyncColor(1,1,"red") ;
    SetSyncColor(1,2,"green") ;
    SetSyncColor(1,3,"blue") ;
    SetSyncColor(1,4,"yellow") ;

    SetSyncColor(2,0,"magenta") ;
    SetSyncColor(2,1,"red") ;
    SetSyncColor(2,2,"green") ;
    SetSyncColor(2,3,"blue") ;
    SetSyncColor(2,4,"yellow") ;
\stopMPdefinitions

\startuseMPgraphic{sync1}
    StartPage ;
        StartSync(1) ;
            SyncHOffset := 0 ;
            SyncWidth   := BackSpace - LeftMarginDistance;
            CollectSyncDataPage ;
         %  ExtendSyncPaths ;  % to top of text area
            PruneSyncPaths ;   % clip top / bottom
            CollapseSyncPaths ;
            MakeSyncPaths ;
          % DrawSyncPaths ;
            FillSyncPaths ;
        StopSync ;
        clip currentpicture to Page ;
        setbounds currentpicture to Page ;
    StopPage ;
\stopuseMPgraphic

\startuseMPgraphic{sync2}
    StartSync(2) ;
        SyncHOffset := -1cm ;
        SyncWidth   :=  1cm ;
        CollectSyncDataRegion(OverlayRegion) ;
        ExtendSyncPaths ;  % to top of text area
        MakeSyncPaths ;
        FillSyncPaths ;
    StopSync ;
    clip currentpicture to OverlayBox leftenlarged 1cm;
    setbounds currentpicture to OverlayBox ;
\stopuseMPgraphic

\defineoverlay[tempoverlay1][\useMPgraphic{sync1}]
\defineoverlay[tempoverlay2][\useMPgraphic{sync2}]

\setupbackgrounds[page][background=tempoverlay1]

\framed[region=yes,background=tempoverlay2,width=14cm,align=normal]{
    \syncposition[2][1]\samplefile{ward}\endgraf
    \syncposition[2][2]\samplefile{ward}\endgraf
    \syncposition[2][3]\samplefile{ward}\endgraf
}


\vskip1cm \hskip1cm \framed[region=yes,background=tempoverlay2,width=16cm,align=normal]{
    \syncposition[2][1]\samplefile{ward}\endgraf
    \syncposition[2][2]\samplefile{ward}\endgraf
    \syncposition[2][3]\samplefile{ward}\endgraf
}

\vskip1cm \hskip1cm \framed[region=yes,background=tempoverlay2,width=10cm,align=normal]{
    \syncposition[2][1]\samplefile{ward}\endgraf
    \syncposition[2][2]\samplefile{ward}\endgraf
    \syncposition[2][3]\samplefile{ward}\endgraf
}


\dorecurse {100} {
% \dorecurse {1} {
    \startchapter[title={Test #1}]
        \syncposition[1][1,reset]\dorecurse{20}{\samplefile{ward}\endgraf}
        \syncposition[1][2]\dorecurse {4}{\samplefile{ward}\endgraf}
        \syncposition[1][3]\dorecurse {7}{\samplefile{ward}\endgraf}
        \syncposition[1][4]\dorecurse {3}{\samplefile{ward}\endgraf}
    \stopchapter
}

\dorecurse {100} {
% \dorecurse {1} {
    \startchapter[title={Test #1}]
        \syncposition[1][1]\dorecurse{1}{\samplefile{ward}\endgraf}
        \syncposition[1][2]\dorecurse{1}{\samplefile{ward}\endgraf}
        \syncposition[1][3]\dorecurse{1}{\samplefile{ward}\endgraf}
        \syncposition[1][4]\dorecurse{1}{\samplefile{ward}\endgraf}
    \stopchapter
}

\stoptext