%D \module
%D   [       file=pack-box,
%D        version=2002.04.12,
%D          title=\CONTEXT\ Packaging Macros,
%D       subtitle=Boxes,
%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.

\writestatus{loading}{ConTeXt Packaging Macros / Boxes}

% to be cleaned up (boring ... so when on long trip or so)
% to be documented (up to users)
% some code can be sped up

%D This module contains all kind of macros for moving content
%D around. Many macros here come from other modules, but
%D depencies made it more clear to isolate them.

% \placeornament

\unprotect

% we need to set the size, else we get dimensions depending
% on the content, which in itself is ok, but can lead to loops
% due to rounding errors (happened in demo-obv)

\definelayer[\v!text-2][\c!position=\v!yes,\c!region=,\c!width=\overlaywidth,\c!height=\overlayheight]
\definelayer[\v!text-1][\c!position=\v!yes,\c!region=,\c!width=\overlaywidth,\c!height=\overlayheight]
\definelayer[\v!text+1][\c!position=\v!yes,\c!region=,\c!width=\overlaywidth,\c!height=\overlayheight]
\definelayer[\v!text+2][\c!position=\v!yes,\c!region=,\c!width=\overlaywidth,\c!height=\overlayheight]

\unexpanded\def\internaltextoverlay#1% will become more generic and installable
  {\startoverlay                     % i.e. probably an overlay by itself
     {\positionregionoverlay\textanchor{\v!text#1}}% see later
     {\composedlayer                   {\v!text#1}}%
   \stopoverlay}

\defineoverlay[\v!text-2][\internaltextoverlay{-2}]
\defineoverlay[\v!text-1][\internaltextoverlay{-1}]
\defineoverlay[\v!text+1][\internaltextoverlay{+1}]
\defineoverlay[\v!text+2][\internaltextoverlay{+2}]

\installcorenamespace {anchor}

\unexpanded\def\defineanchor
  {\doquadrupleempty\pack_anchors_define}

\def\pack_anchors_define[#1][#2][#3][#4]% name targetlayer layersetting framedsetting
  {\setvalue{\??anchor#1}{\pack_anchors_process_defined{#2}{#3}{#4}}}

\def\pack_anchors_process_defined#1#2#3%
  {\def\pack_anchors_process_defined_indeed[##1][##2]%
     {\ifsecondargument
        \def\next{\pack_anchors_process_indeed{#1}{#2,##1}{#3,##2}}%
      \else\iffirstargument
        \def\next{\pack_anchors_process_indeed{#1}{#2,##1}{#2,##1}}%
      \else
        \def\next{\pack_anchors_process_indeed{#1}{#2}{#3}}%
      \fi\fi
      \next}%
   \dodoubleempty\pack_anchors_process_defined_indeed}

\unexpanded\def\anchor[#1]%
  {\begingroup
   \edef\currentanchor{#1}%
   \ifcsname\??anchor\currentanchor\endcsname
     \expandafter\pack_anchor_predefined
   \else
     \expandafter\pack_anchor_notdefined
   \fi}

\def\pack_anchor_predefined
  {\csname\??anchor\currentanchor\endcsname}

\def\pack_anchor_notdefined
  {\dodoubleempty\pack_anchor_notdefined_indeed}

\def\pack_anchor_notdefined_indeed
  {\ifsecondargument
     \expandafter\pack_anchor_notdefined_two
   \else
     \expandafter\pack_anchor_notdefined_one
   \fi}

\def\pack_anchor_notdefined_one[#1][#2]{\pack_anchors_process_indeed\currentanchor{#1}{#1}}
\def\pack_anchor_notdefined_two[#1][#2]{\pack_anchors_process_indeed\currentanchor{#1}{#2}}

\def\pack_anchors_process_indeed#1#2#3%
  {\dowithnextbox{\pack_anchors_process_finish{#1}{#2}{#3}}\vbox}

\newbox  \b_pack_anchors
\newdimen\d_pack_anchors_width
\newdimen\d_pack_anchors_height
\newdimen\d_pack_anchors_depth

\definelayer[anchor] % \defineoverlay[anchor][\ruledhbox{\flushlayer[anchor]}]

\def\pack_anchors_process_finish#1#2#3% brrr: we need to apply offset only once .. a bit messy
  {\checkpositionoverlays
   % for the moment we ignore the depth
   \setbox\b_pack_anchors\box\nextbox
   \d_pack_anchors_width \wd\b_pack_anchors
   \d_pack_anchors_height\ht\b_pack_anchors
   \d_pack_anchors_depth \dp\b_pack_anchors
   \setbox\scratchbox\emptyhbox
   \wd\scratchbox\d_pack_anchors_width
   \ht\scratchbox\d_pack_anchors_height
   \dp\scratchbox\d_pack_anchors_depth
   \setlayer
     [anchor]
     [\c!width=\d_pack_anchors_width,
      \c!height=\d_pack_anchors_height,
      \c!offset=\zeropoint,
      #2,#3]
     {\setlayer[#1]{\box\b_pack_anchors}}% % #1 uses ovelaywidth/height
   \framed
     [\c!background=anchor,
      \c!offset=\v!overlay,
      \c!frame=\v!off,
      #3]
     {\box\scratchbox}%
  \endgroup}

% collectors

\installcorenamespace{collectorbox}

\unexpanded\def\definecollector
  {\dodoubleargument\dodefinecollector}

\def\dodefinecollector[#1][#2]%
  {\ifcsname\??collectorbox#1\endcsname \else
     \expandafter\newbox\csname\??collectorbox#1\endcsname
   \fi
   \resetcollector[#1]%
   \setupcollector
     [#1]
     [\c!state=\v!start,
      \c!x=\zeropoint,\c!y=\zeropoint,
      \c!offset=\zeropoint,\c!rotation=, % geen 0 !
      \c!hoffset=\zeropoint,\c!voffset=\zeropoint,
      \c!location=rb,\c!corner=,#2]}

\unexpanded\def\setupcollector
  {\dodoubleargument\dosetupcollector}

\def\dosetupcollector[#1][#2]%
  {\def\docommand##1{\getparameters[\??cb##1][#2]}%
   \processcommalist[#1]\docommand}

\def\setcollector
  {\dodoubleargument\dosetcollector}

\def\dosetcollector[#1][#2]%
  {\bgroup
   \forgetall
   \dontcomplain
   \dowithnextbox
     {\ifcsname\??collectorbox#1\endcsname
        \dodosetcollector[#1][#2]%
      \else
        \writestatus{collector}{unknown layer #1}%
      \fi
      \egroup}
     \hbox}

\def\collectorparameter#1{\csname\??cb\currentcollector#1\endcsname}

\def\dodosetcollector[#1][#2]% todo: keep reference point
  {\def\currentcollector{#1}%
   \chardef\collectorbox\csname\??collectorbox#1\endcsname
   \getparameters[\??cb#1][#2]%
   \d_pack_layers_x_size\wd\collectorbox
   \d_pack_layers_y_size\ht\collectorbox
   \doifvaluesomething{\??cb#1\c!rotation}
     {\setbox\nextbox\hbox
        {\rotate
           [\c!location=\v!high,
            \c!rotation=\collectorparameter\c!rotation]
           {\flushnextbox}}}%
   \advance\d_pack_layers_y_size\dp\collectorbox
   \d_pack_layers_x_position\collectorparameter\c!x
   \advance\d_pack_layers_x_position\collectorparameter\c!hoffset
   \d_pack_layers_y_position\collectorparameter\c!y
   \advance\d_pack_layers_y_position\collectorparameter\c!voffset
   \doifelse\v!middle{\collectorparameter\c!corner}
     {\ifdim\d_pack_layers_x_size>\zeropoint
        \advance\d_pack_layers_x_position.5\d_pack_layers_x_size
      \fi
      \ifdim\d_pack_layers_y_size>\zeropoint
        \advance\d_pack_layers_y_position.5\d_pack_layers_y_size
      \fi}%
     {\normalexpanded{\noexpand\doifinset{\v!bottom}{\collectorparameter\c!corner}}
        {\ifdim\d_pack_layers_y_size>\zeropoint
           \advance\d_pack_layers_y_position-\d_pack_layers_y_size
           \d_pack_layers_y_position-\d_pack_layers_y_position
         \fi}%
      \normalexpanded{\noexpand\doifinset{\v!right}{\collectorparameter\c!corner}}
        {\ifdim\d_pack_layers_x_size>\zeropoint
           \advance\d_pack_layers_x_position-\d_pack_layers_x_size
           \d_pack_layers_x_position-\d_pack_layers_x_position
         \fi}}%
   \setbox\nextbox\hbox
     {\alignedbox[\collectorparameter\c!location]\vbox{\flushnextbox}}%
   \boxmaxdepth\zeropoint % really needed, nice example
   \global\advance\boxhdisplacement\d_pack_layers_x_position
   \ifdim\boxhdisplacement<\zeropoint
     \global\setbox\collectorbox\hbox
       {\hskip-\boxhdisplacement
        \box\collectorbox}%
   \fi
   \global\advance\boxvdisplacement\d_pack_layers_y_position
   \ifdim\boxvdisplacement<\zeropoint
     \global\setbox\collectorbox\hbox
       {\lower-\boxvdisplacement
        \box\collectorbox}%
   \fi
   \d_pack_layers_x_size\wd\collectorbox
   \d_pack_layers_y_size\ht\collectorbox
   \advance\d_pack_layers_y_size\dp\collectorbox
   \global\setbox\collectorbox\hbox
     {\box\collectorbox
      \hskip-\d_pack_layers_x_size
      \hskip\d_pack_layers_x_position\relax
      \ifdim\boxhdisplacement<\zeropoint
        \hskip-\boxhdisplacement
      \fi
      \lower\d_pack_layers_y_position\hbox
        {\ifdim\boxvdisplacement<\zeropoint
           \lower-\boxvdisplacement\flushnextbox
         \else
           \flushnextbox
         \fi}}%
   % combine height and depth into depth only (later flushed as height)
   \global\setbox\collectorbox\hbox
     {\lower\ht\collectorbox\box\collectorbox}%
   % just to be sure
   \ifdim\wd\collectorbox<\d_pack_layers_x_size
     \wd\collectorbox\d_pack_layers_x_size
   \fi}

\def\flushcollector[#1]%
  {\ifcsname\??collectorbox#1\endcsname
     \doifnotvalue{\??cb#1\c!state}\v!stop
       {\vbox
          {\hbox
             {\doifelsevalue{\??cb#1\c!state}\v!repeat
                {\let\next\copy}{\let\next\box}%
              \raise\dp\csname\??collectorbox#1\endcsname
              \next\csname\??collectorbox#1\endcsname}}}%
   \else
     \writestatus{collector}{unknown collector #1}%
   \fi}

\def\composedcollector#1{\flushcollector[#1]}

\def\resetcollector[#1]%
  {\ifcsname\??collectorbox#1\endcsname
     \global\setbox\csname\??collectorbox#1\endcsname\emptybox
   \fi}

\def\adaptcollector
  {\dodoubleargument\doadaptcollector}

\def\doadaptcollector[#1][#2]% % a typical case where \global\wd looks better in the code
  {\bgroup
   \def\currentcollector{#1}%
   \chardef\collectorbox\csname\??collectorbox#1\endcsname
   \getparameters[\??cb#1][\c!voffset=\zeropoint,\c!hoffset=\zeropoint,#2]%
   \scratchdimen\wd\collectorbox
   \advance\scratchdimen\collectorparameter\c!hoffset
   \global\wd\collectorbox\scratchdimen
   \scratchdimen\ht\collectorbox
   \advance\scratchdimen\collectorparameter\c!voffset
   \global\ht\collectorbox\scratchdimen
   \egroup}

%\definecollector[test]
%\setcollector[test]
%  [location=rb]
%  {\externalfigure[koe][frame=on,width=3cm]}
%\setcollector[test]
%  [corner={right,bottom},location={left,top}]
%  {\framed{gans}}
%\composedcollector{test}

\definecollector
  [caption]

\def\collectedtext
  {\dodoubleempty\docollectedtext}

\def\docollectedtext[#1][#2]#3%
  {\bgroup
   \dowithnextbox
     {\setcollector
        [caption]
        {\flushnextbox}%
      \setcollector
        [caption][#1]
        {\getparameters[\??du][\c!style=,\c!color=,#2]%
         \dousestyleparameter\@@dustyle
         \setupinterlinespace
         \framed % watch the special setting of kader/overlay
           [\c!frame=\v!overlay,\c!foregroundcolor=\@@ducolor,\c!foregroundstyle=\@@dustyle,#2]
           {#3}}%
      \composedcollector{caption}%
      \egroup}%
     \hbox}

% \collectedtext
%   [corner={right,bottom},location={left,top}]
%   [background=color,backgroundcolor=white,offset=0pt]
%   {gans}
%   {\externalfigure[koe][width=3cm]}
%
% \collectedtext
%   [rotation=90,corner={right,bottom},location={right,top}]
%   [frame=on,offset=0pt]
%   {gans}
%   {\externalfigure[koe][width=3cm]}
%
% \collectedtext
%   [rotation=90,corner={left,bottom},location={left,top}]
%   [frame=on,offset=0pt]
%   {gans}
%   {\externalfigure[koe][width=3cm]}

\installcorenamespace {layeredtext}
\installcorenamespace {layeredtextlayer}
\installcorenamespace {layeredtextframed}

\installsimpleframedcommandhandler \??layeredtext {layeredtext} \??layeredtext

\newdimen\d_pack_layeredtexts_width
\newdimen\d_pack_layeredtexts_height

\definelayer % private
  [\??layeredtextlayer]

\setuplayer % private
  [\??layeredtextlayer]
  [\c!width=\d_pack_layeredtexts_width,
   \c!height=\d_pack_layeredtexts_height]

\defineframed % private
  [\??layeredtextframed]
  [\c!offset=\v!overlay,
   \c!frame=\v!off,
   \c!background={\v!foreground,\??layeredtextlayer},
   \c!width=\d_pack_layeredtexts_width,
   \c!height=\d_pack_layeredtexts_height]

\setuplayeredtext % public (the attached data, usually small stuff, not the main thing)
  [\c!frame=\v!overlay,
   \c!color=,
   \c!style=,
   \c!foregroundcolor=\layeredtextparameter\c!color,
   \c!foregroundstyle=\layeredtextparameter\c!style]

\unexpanded\def\layeredtext
  {\bgroup
   \let\currentlayeredtext\empty
   \dodoubleempty\pack_layeredtexts_place}

\unexpanded\def\placelayeredtext[#1]%
  {\bgroup
   \edef\currentlayeredtext{#1}%
   \dodoubleempty\pack_layeredtexts_place}

\def\pack_layeredtexts_place[#1][#2]#3% layersettings content(framed)settings content
  {\setupcurrentlayeredtext[#2]%
   \dowithnextbox
     {\d_pack_layeredtexts_width \wd\nextbox
      \d_pack_layeredtexts_height\ht\nextbox
      \begingroup % preserve \nextbox
      \setlayer
        [\??layeredtextlayer]%
        [#1]%
        {\setfalse\fontattributeisset
         \uselayeredtextstyleparameter\c!style
         \ifconditional\fontattributeisset
           \setupinterlinespace
         \fi
         \inheritedlayeredtextframed{#3}}%
      \endgroup
      \placeframed[\??layeredtextframed]{\flushnextbox}%
      \egroup}%
     \hbox}

% \layeredtext
%   [corner={right,bottom},location={left,top}]
%   [background=color,backgroundcolor=white,offset=0pt]
%   {gans}
%   {\externalfigure[koe][width=3cm]}
%
% \layeredtext
%   [rotation=90,corner={right,bottom},location={right,top}]
%   [frame=on,offset=0pt]
%   {gans}
%   {\externalfigure[koe][width=3cm]}
%
% \layeredtext
%   [rotation=90,corner={left,bottom},location={left,top}]
%   [frame=on,offset=0pt]
%   {gans}
%   {\externalfigure[koe][width=3cm]}

\unexpanded\def\ornamenttext
  {\dodoubleempty\pack_ornament_text}

\def\pack_ornament_text[#1][#2]%
  {\bgroup
   \doifassignmentelse{#1}
     {\getdummyparameters[\c!alternative=\v!a,#1]%
      \doifelse{\directdummyparameter\c!alternative}\v!a
        {\egroup\collectedtext}%
        {\egroup\layeredtext  }%
      [#1][#2]}%
     {\egroup\getvalue{#1}}}

\unexpanded\def\defineornament
  {\dotripleempty\dodefineornament}

\def\dodefineornament[#1][#2][#3]%
  {\setuvalue{#1}{\pack_ornament_text[#2][#3]}}

% \defineornament
%   [affiliation]
%   [rotation=90,corner={right,bottom},location={right,top},
%    hoffset=-.25ex]
%   [frame=on,background=color,backgroundcolor=red,offset=0pt]
%
% \ruledhbox{\affiliation{gans}{\externalfigure[koe][width=3cm]}}
%
% \defineornament
%   [affiliation]
%   [rotation=90,corner={right,bottom},location={right,top},
%    hoffset=-.25ex,alternative=b]
%   [frame=on,background=color,backgroundcolor=red,offset=0pt]
%
% \ruledhbox{\affiliation{gans}{\externalfigure[koe][width=3cm]}}
%
% \defineornament
%   [affiliation]
%   [rotation=90,corner={right,bottom},location={left,top},
%    hoffset=.25ex,voffset=.25ex,alternative=a]
%   [background=color,style=\ss\tfxx,backgroundcolor=white,offset=0pt]
%
% \affiliation{photo}{\externalfigure[molen][width=3cm]}
%
% \defineornament
%   [affiliation]
%   [rotation=90,corner={right,bottom},location={left,top},
%    hoffset=.25ex,voffset=.25ex,alternative=b]
%   [background=color,style=\ss\tfxx,backgroundcolor=white,offset=0pt]
%
% \affiliation{drawing}{\externalfigure[hakker][width=3cm]}

% pas op: aanpassen aan nieuwe layer hoek ankers en columnset

\newcount\nofbleeds % per pag

\unexpanded\def\setupbleeding
  {\dodoubleempty\getparameters[\??bg]}

\setupbleeding
  [\c!location=l,
   \c!stretch=\v!yes,
   \c!width=3cm,
   \c!height=3cm,
   \c!offset=2mm,
   \c!page=\v!no,
   \c!voffset=\@@bgoffset,
   \c!hoffset=\@@bgoffset]

\unexpanded\def\bleed
  {\dosingleempty\pack_boxes_bleed}

\def\bleedwidth {\the\hsize}%
\def\bleedheight{\the\vsize}%

\def\pack_boxes_bleed[#1]#2%
  {\hbox\bgroup
   \xdef\bleedwidth {\the\hsize}%
   \xdef\bleedheight{\the\vsize}%
   \global\advance\nofbleeds\plusone
   \getparameters[\??bg][#1]%
   \!!doneafalse % left
   \!!donebfalse % right
   \!!donecfalse % top
   \!!donedfalse % bottom
   % replace this part ! todo: default location
   \processaction
     [\@@bglocation]
     [ t=>\!!donectrue\let\@@bghoffset\!!zeropoint,
       b=>\!!donedtrue\let\@@bghoffset\!!zeropoint,
       l=>\!!doneatrue\let\@@bgvoffset\!!zeropoint,
       r=>\!!donebtrue\let\@@bgvoffset\!!zeropoint,
      bl=>\!!doneatrue\!!donedtrue,
      lb=>\!!doneatrue\!!donedtrue,
      br=>\!!donebtrue\!!donedtrue,
      rb=>\!!donebtrue\!!donedtrue,
      tl=>\!!doneatrue\!!donectrue,
      lt=>\!!doneatrue\!!donectrue,
      tr=>\!!donebtrue\!!donectrue,
      rt=>\!!donebtrue\!!donectrue]%
   \doifelse\@@bgstretch\v!yes\donetrue\donefalse
   \scratchdimen\@@bgwidth
   \edef\currentbgposition  {\??bg:\number\nofbleeds}%
   \edef\currentpageposition{page:0}% todo: per page
   \ifdone
     \if!!donea
       \advance\scratchdimen\dimexpr    \MPx\currentbgposition-\MPx\currentpageposition\relax
     \else\if!!doneb
       \scratchdimen\dimexpr\paperwidth-\MPx\currentbgposition+\MPx\currentpageposition\relax % not checked
     \fi\fi
   \fi
   \advance\scratchdimen\@@bghoffset
   \xdef\bleedwidth{\the\scratchdimen}%
   \scratchdimen\@@bgheight
   \ifdone
     \if!!donec
       \scratchdimen\dimexpr\paperheight-\MPy\currentbgposition+\MPy\currentpageposition\relax % not checked
     \else\if!!doned
       \advance\scratchdimen\dimexpr     \MPy\currentbgposition-\MPy\currentpageposition\relax % not checked
     \fi\fi
   \fi
   \advance\scratchdimen\@@bgvoffset
   \xdef\bleedheight{\the\scratchdimen}%
   %
   \bgroup
   \hsize\bleedwidth
   \vsize\bleedheight
   \global\setbox\globalscratchbox\hbox{#2}%
   \egroup
   \setbox\scratchbox\box\globalscratchbox
   %
   \doif\@@bgpage\v!yes
     {\setbox\scratchbox\topskippedbox{\box\scratchbox}}%
   \setbox\scratchbox\hbox to \@@bgwidth
     {\if!!donea\hss\fi\box\scratchbox\if!!doneb\hss\fi}%
   \if!!doned
     \setbox\scratchbox\hbox
       {\lower\bleedheight\hbox{\raise\@@bgheight\box\scratchbox}}%
   \fi
   \wd\scratchbox\@@bgwidth
   \ht\scratchbox\@@bgheight
   \dp\scratchbox\zeropoint
   \ifdone
     \hpos\currentbgposition{\box\scratchbox}%
   \else
     \box\scratchbox
   \fi
   \egroup}

\setupbleeding
  [\c!stretch=\v!yes]

\defineexternalfigure
  [bleed] % should be \v!bleed
  [\c!width=\bleedwidth,
   \c!height=\bleedheight]

% \placefigure[left]{none}
%   {\bleed[width=5cm,height=3cm,location=lt]{\externalfigure[koe][bleed]}}
%
% \input tufte
%
% \placefigure[left]{none}
%   {\bleed[width=5cm,height=3cm,location=l]{\externalfigure[koe][bleed]}}
%
% \input tufte
%
% \placefigure[right]{none}
%   {\bleed[width=5cm,height=3cm,location=r]{\externalfigure[koe][bleed]}}
%
% \input tufte
%
% \placefigure
%   [top,none]
%   {} % no caption
%   {\bleed
%      [hoffset=-\backspace,
%       voffset=3mm,
%       width=0cm,
%       height=6\lineheight,
%       page=yes, % correct for topskip
%       location=lt]
%      {\externalfigure[koe][bleed][frame=on]}}

% \setlayerframed[layer id][layer settings][framed setting]{data}
% \setlayerframed[layer id][combined settings]{data}

% tricky: offsets apply to both the layer and the framed; it makes sense to
% only apply the offset to ...

\def\setlayerframed
  {\dotripleempty\pack_layers_set_framed}

\def\pack_layers_set_framed
  {\ifthirdargument
     \singleexpandafter\pack_layers_set_framed_t
   \else\ifsecondargument
     \doubleexpandafter\pack_layers_set_framed_d
   \else
     \doubleexpandafter\pack_layers_set_framed_s
   \fi\fi}

\def\pack_layers_set_framed_s[#1][#2][#3]%
  {\setlayer[#1][\c!width=\wd\nextbox,\c!height=\ht\nextbox,\c!offset=\zeropoint]%
     \normalframedwithsettings[\c!location=\v!normal]} % diffrent kind of location

\def\pack_layers_set_framed_d[#1][#2][#3]%
  {\setlayer[#1][\c!width=\wd\nextbox,\c!height=\ht\nextbox,#2,\c!offset=\zeropoint]%
     \normalframedwithsettings[\c!location=\v!normal,#2]} % diffrent kind of location

\def\pack_layers_set_framed_t[#1][#2][#3]%
  {\setlayer[#1][#2]%
     \normalframedwithsettings[#3]}

\def\setlayertext
  {\dotripleempty\pack_layers_set_text}

\def\pack_layers_set_text[#1][#2][#3]%
  {\bgroup
   \getparameters
     [\??lx]
     [\c!align=,
      \c!width=\hsize,
      \c!color=,
      \c!style=,
      #3]%
   \dowithnextboxcontent
     {\forgetall
      \hsize\@@lxwidth
      \normalexpanded{\setupalign[\@@lxalign]}%
      \dousestyleparameter\@@lxstyle}
     {\setlayer[#1][#2]{\strut\dousecolorparameter\@@lxcolor\flushnextbox}%
      \egroup}%
   \vtop}

% \setupbackgrounds
%   [page]
%   [background=pagefigures]
%
% \definelayer
%   [pagefigures]
%   [x=-2mm,
%    y=-2mm,
%    width=\paperwidth,
%    height=\paperheight]
%
% \definelayerpreset [lefttop]     [corner={left,top},location={right,bottom}]
% \definelayerpreset [righttop]    [corner={right,top},location={left,bottom}]
% \definelayerpreset [leftbottom]  [corner={left,bottom},location={right,top}]
% \definelayerpreset [rightbottom] [corner={right,bottom},location={left,top}]
% \definelayerpreset [middle]      [corner=middle,location=middle]
%
% \setlayer[pagefigures][preset=lefttop]
% \setlayer[pagefigures][preset=righttop]
% \setlayer[pagefigures][preset=leftbottom]
% \setlayer[pagefigures][preset=rightbottom]

\definelayerpreset
  [\v!left\v!top]
  [\c!corner={\v!left,\v!top},\c!location={\v!right,\v!bottom}]

\definelayerpreset
  [\v!right\v!top]
  [\c!corner={\v!right,\v!top},\c!location={\v!left,\v!bottom}]

\definelayerpreset
  [\v!left\v!bottom]
  [\c!corner={\v!left,\v!bottom},\c!location={\v!right,\v!top}]

\definelayerpreset
  [\v!right\v!bottom]
  [\c!corner={\v!right,\v!bottom},\c!location={\v!left,\v!top}]

\definelayerpreset
  [\v!middle]
  [\c!corner=\v!middle,\c!location=\v!middle]

\definelayerpreset
  [\v!middle\v!top]
  [\c!location=\v!bottom,\c!corner=\v!top,\c!dx=.5\layerwidth]

\definelayerpreset
  [\v!middle\v!bottom]
  [\c!location=\v!top,\c!corner=\v!bottom,\c!dx=.5\layerwidth]

\definelayerpreset
  [\v!middle\v!left]
  [\c!location=\v!right,\c!corner=\v!left,\c!dy=.5\layerheight]

\definelayerpreset
  [\v!middle\v!right]
  [\c!location=\v!left,\c!corner=\v!right,\c!dy=.5\layerheight]

% left and right hanging:

\definelayerpreset
  [\v!left\v!top\v!left]
  [\c!location={\v!left,\v!bottom},\c!corner={\v!left,\v!top}]

\definelayerpreset
  [\v!right\v!top\v!right]
  [\c!location={\v!right,\v!bottom},\c!corner={\v!right,\v!top}]

\installcorenamespace{alignedboxes}

\unexpanded\def\alignedbox{\dosingleempty\pack_boxes_aligned_box}
\unexpanded\def\aligned   {\dosingleempty\pack_boxes_aligned}

\def\pack_boxes_aligned_box[#1]{\bgroup\serializecommalist[#1]\dowithnextboxcs\pack_boxes_aligned_finish}
\def\pack_boxes_aligned    [#1]{\bgroup\serializecommalist[#1]\dowithnextboxcs\pack_boxes_aligned_finish\hbox}

\def\pack_boxes_aligned_finish
  {\csname\??alignedboxes
     \ifcsname\??alignedboxes\serializedcommalist\endcsname\serializedcommalist\else\v!middle\fi
   \endcsname{\flushnextbox}%
   \egroup}

\letvalue{\??alignedboxes                  }\middlebox
\letvalue{\??alignedboxes\v!middle         }\middlebox
\letvalue{\??alignedboxes\v!middle\v!middle}\middlebox
\letvalue{\??alignedboxes\v!left           }\leftbox
\letvalue{\??alignedboxes\v!left  \v!top   }\lefttopbox
\letvalue{\??alignedboxes\v!left  \v!bottom}\leftbottombox
\letvalue{\??alignedboxes\v!right          }\rightbox
\letvalue{\??alignedboxes\v!right \v!top   }\righttopbox
\letvalue{\??alignedboxes\v!right \v!bottom}\rightbottombox
\letvalue{\??alignedboxes\v!bottom         }\bottombox
\letvalue{\??alignedboxes\v!bottom\v!left  }\bottomleftbox
\letvalue{\??alignedboxes\v!bottom\v!right }\bottomrightbox
\letvalue{\??alignedboxes\v!top            }\topbox
\letvalue{\??alignedboxes\v!top   \v!left  }\topleftbox
\letvalue{\??alignedboxes\v!top   \v!right }\toprightbox
\letvalue{\??alignedboxes\v!line           }\baselinemiddlebox % \v!grid is taken
\letvalue{\??alignedboxes\v!line  \v!left  }\baselineleftbox
\letvalue{\??alignedboxes\v!line  \v!middle}\baselinemiddlebox
\letvalue{\??alignedboxes\v!line  \v!right }\baselinerightbox
\letvalue{\??alignedboxes                 c}\middlebox
\letvalue{\??alignedboxes                 l}\leftbox
\letvalue{\??alignedboxes                 r}\rightbox
\letvalue{\??alignedboxes                 b}\bottombox
\letvalue{\??alignedboxes                 t}\topbox
\letvalue{\??alignedboxes                lt}\lefttopbox
\letvalue{\??alignedboxes                lb}\leftbottombox
\letvalue{\??alignedboxes                rt}\righttopbox
\letvalue{\??alignedboxes                rb}\rightbottombox
\letvalue{\??alignedboxes                tl}\topleftbox
\letvalue{\??alignedboxes                bl}\bottomleftbox
\letvalue{\??alignedboxes                tr}\toprightbox
\letvalue{\??alignedboxes                br}\bottomrightbox
\letvalue{\??alignedboxes                 m}\middlebox
\letvalue{\??alignedboxes                 g}\baselinemiddlebox
\letvalue{\??alignedboxes                gl}\baselineleftbox
\letvalue{\??alignedboxes                gc}\baselinemiddlebox
\letvalue{\??alignedboxes                gr}\baselinerightbox

% left/right/top/bottomoffset -> dimensions change
% x/y | method=fixed          -> dimensions don't change

\unexpanded\def\offsetbox{\dosingleempty\pack_boxes_offset_box}
\unexpanded\def\offset   {\dosingleempty\pack_boxes_offset}

\def\pack_boxes_offset_box[#1]{\bgroup\dowithnextbox{\pack_boxes_offsetfinish{#1}}}
\def\pack_boxes_offset    [#1]{\bgroup\dowithnextbox{\pack_boxes_offsetfinish{#1}}\hbox}

\def\pack_boxes_offsetfinish#1%
  {\getparameters[\??ox]
     [\c!x=\zeropoint,
      \c!y=\zeropoint,
      \c!width=\wd\nextbox,
      \c!height=\ht\nextbox,
      \c!depth=\dp\nextbox,
      \c!location=,
      \c!leftoffset=\zeropoint,
      \c!rightoffset=\zeropoint,
      \c!topoffset=\zeropoint,
      \c!bottomoffset=\zeropoint,
      \c!method=,
      #1]%
   \donefalse
   \ifdim\@@oxleftoffset  =\zeropoint\else\donetrue\fi
   \ifdim\@@oxrightoffset =\zeropoint\else\donetrue\fi
   \ifdim\@@oxtopoffset   =\zeropoint\else\donetrue\fi
   \ifdim\@@oxbottomoffset=\zeropoint\else\donetrue\fi
   \ifdone
     \doif\@@oxmethod\v!fixed % new
       {\ifdim\@@oxleftoffset=\zeropoint
          \ifdim\@@oxrightoffset=\zeropoint \else
            \edef\@@oxx{\the\dimexpr-\@@oxrightoffset}%
            \let\@@oxrightoffset\zeropoint
          \fi
        \else
          \let\@@oxx\@@oxleftoffset
          \let\@@oxleftoffset\zeropoint
        \fi
        \ifdim\@@oxtopoffset=\zeropoint
          \ifdim\@@oxbottomoffset=\zeropoint \else
            \edef\@@oxy{\the\dimexpr-\@@oxbottomoffset}%
            \let\@@oxbottomoffset\zeropoint
          \fi
        \else
          \let\@@oxy\@@oxtopoffset
          \let\@@oxtopoffset\zeropoint
        \fi
        \donefalse}%
   \fi
   \ifdone
     \setbox\nextbox\vbox
       {\forgetall % already done
        \offinterlineskip
        \vskip\@@oxtopoffset
        \hbox
          {\hskip\@@oxleftoffset
           \box\nextbox
           \hskip\@@oxrightoffset}%
        \vskip\@@oxbottomoffset}%
     \ht\nextbox\htdp\nextbox
     \dp\nextbox\zeropoint
   \fi
   \freezedimenmacro\@@oxwidth
   \freezedimenmacro\@@oxheight
   \freezedimenmacro\@@oxdepth
   \setbox\nextbox\hbox
     {\hskip\@@oxx\lower\@@oxy\hbox
        {\doifelsenothing\@@oxlocation
           {\box\nextbox}
           {\alignedbox[\@@oxlocation]\hbox{\box\nextbox}}}}%
   \wd\nextbox\@@oxwidth
   \ht\nextbox\@@oxheight
   \dp\nextbox\@@oxdepth
   \box\nextbox
   \egroup}

% \useMPlibrary[pre] \setupbackgrounds[page][background=pagegrid]
%
% \placefigure[left,none]{}{\offset[leftoffset=1cm]{\externalfigure[koe][breedte=3cm]}}
% \input tufte
% \placefigure[left,none]{}{\offset[rightoffset=1cm]{\externalfigure[koe][breedte=3cm]}}
% \input tufte
% \placefigure[left,none]{}{\offset[topoffset=1cm]{\externalfigure[koe][breedte=3cm]}}
% \input tufte
% \placefigure[left,none]{}{\offset[bottomoffset=1cm]{\externalfigure[koe][breedte=3cm]}}
% \input tufte

%\ruledhbox{\offsetbox[x=-1cm,y=-1cm,location=c]
%  {\framed[width=4cm,height=4cm]{x}}}

% Some old code:
%
% \ltabbed{\romannumerals{3}}{\romannumerals{1}} test \endgraf
% \ltabbed{\romannumerals{3}}{\romannumerals{2}} test \endgraf
% \ltabbed{\romannumerals{3}}{\romannumerals{3}} test \endgraf
%
% \rtabbed{\romannumerals{3}}{\romannumerals{1}} test \endgraf
% \rtabbed{\romannumerals{3}}{\romannumerals{2}} test \endgraf
% \rtabbed{\romannumerals{3}}{\romannumerals{3}} test \endgraf
%
% \ctabbed{\romannumerals{3}}{\romannumerals{1}} test \endgraf
% \ctabbed{\romannumerals{3}}{\romannumerals{2}} test \endgraf
% \ctabbed{\romannumerals{3}}{\romannumerals{3}} test \endgraf

\def\pack_boxes_tabbed#1#2#3#4%
  {\dontleavehmode
   \begingroup
   \setbox\scratchbox\hbox{#3}%
   \hbox to \wd\scratchbox{#1#4#2}%
   \endgroup}

\unexpanded\def\ltabbed{\pack_boxes_tabbed\relax\hss}
\unexpanded\def\rtabbed{\pack_boxes_tabbed\hss  \relax}
\unexpanded\def\ctabbed{\pack_boxes_tabbed\hss  \hss}

\let\mtabbed\ctabbed

% to be documented

\unexpanded\def\phantombox[#1]% == \framed[\c!empty=\v!yes,\c!offset=\v!overlay,#1]{}
  {\hbox\bgroup
   \getdummyparameters
     [\c!width=\zeropoint,%
      \c!height=\zeropoint,%
      \c!depth=\zeropoint,#1]%
   \setbox\scratchbox\emptyhbox
   \wd\scratchbox\directdummyparameter\c!width
   \ht\scratchbox\directdummyparameter\c!height
   \dp\scratchbox\directdummyparameter\c!depth
   \box\scratchbox
   \egroup}

%  \backgroundimage{1}{\hsize}{\vsize}{\externalfigure[cow][\c!width=3cm]}

\unexpanded\def\backgroundimage#1#2#3% repeat hsize vsize
  {\bgroup
   \forgetall
   \dowithnextbox{\pack_boxes_background_image{#1}{#2}{#3}}\hbox}

\def\pack_boxes_background_image#1#2#3%
  {\offinterlineskip
   \ifcase#1\relax
     % just one
   \else
     \scratchdimen#2\divide\scratchdimen\wd\nextbox\count0\scratchdimen\advance\count0\plusone
     \scratchdimen#3\divide\scratchdimen\ht\nextbox\count2\scratchdimen\advance\count2\plusone
     % to be considered: methods
     \ifcase#1%
     \or % x and y
       \setbox\nextbox\hbox{\dorecurse{\count0}{\copy\nextbox}}%
       \setbox\nextbox\vbox{\dorecurse{\count2}{\copy\nextbox\endgraf}}%
     \or % x
       \setbox\nextbox\hbox{\dorecurse{\count0}{\copy\nextbox}}%
     \or % y
       \setbox\nextbox\vbox{\dorecurse{\count2}{\copy\nextbox\endgraf}}%
     \fi
   \fi
   \ifdim\wd\nextbox>#2\relax
     \setbox\nextbox\hbox to #2{\hss\box\nextbox\hss}%
     \setbox\nextbox\hbox{\normalexpanded{\clip[\c!width=#2,\c!height=\the\ht\nextbox]{\box\nextbox}}}%
   \fi
   \ifdim\ht\nextbox>#3\relax
     \setbox\nextbox\vbox to #3{\vss\box\nextbox\vss}%
     \setbox\nextbox\hbox{\normalexpanded{\clip[\c!width=\the\wd\nextbox,\c!height=#3]{\box\nextbox}}}%
   \fi
   \box\nextbox
   \egroup}

\protect \endinput