%D \module
%D   [       file=page-pls,
%D        version=2003.03.16,
%D          title=\CONTEXT\ Page Macros,
%D       subtitle=Page Setup,
%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 Page Macros / Extra Page Building}

%D This still needs some work, especially the dimensions need to be
%D checked cq.\ optimized. Beware: method has become alternative!

%D This feature has been present for a while but has never been
%D exploited: pluggable pagebuilders. The next example code
%D demonstrates the application of one such a plug-in. This variant
%D support \type {page}, \type {leftpage} and \type {rightpage}
%D definitions where specific areas are placed with the \type
%D {\pagearea} command.
%D
%D \starttyping
%D \setupheadertexts[the header text]
%D \setupfootertexts[a pretty long left footer text][something right]
%D \setupbottomtexts[a not so long bottom text][another right thing]
%D \setuptexttexts  [margin][something marginal][indeed]
%D
%D \startpagelayout[leftpage]
%D   \setupTABLE[offset=overlay]
%D   \setupTABLE[c][1][width=\leftmarginwidth]
%D   \setupTABLE[c][2][width=\textwidth]
%D   \setupTABLE[c][3][width=\rightmarginwidth]
%D   \bTABLE
%D     \bTR
%D       \bTD[nx=3,background=color,backgroundcolor=green]
%D         \pagearea[header][text][middle]
%D       \eTD
%D     \eTR
%D     \bTR
%D       \bTD \pagearea[text][margin][left] \eTD
%D       \bTD[nx=2] \pagearea[text] \eTD
%D     \eTR
%D     \bTR
%D       \bTD[nx=3,offset=overlay]
%D         {\bTABLE
%D            \bTR
%D              \bTD \pagearea[footer][text][left] \eTD
%D              \bTD \pagearea[bottom][text][left] \eTD
%D            \eTR
%D          \eTABLE}
%D        \eTD
%D     \eTR
%D   \eTABLE
%D \stoppagelayout
%D
%D \startpagelayout[rightpage]
%D   \setupTABLE[offset=overlay]
%D   \setupTABLE[c][1][width=\leftmarginwidth]
%D   \setupTABLE[c][2][width=\textwidth]
%D   \setupTABLE[c][3][width=\rightmarginwidth]
%D   \bTABLE
%D     \bTR
%D       \bTD[nx=3] \pagearea[header][text][middle] \eTD
%D     \eTR
%D     \bTR
%D       \bTD \pagearea[text][margin][left] \eTD
%D       \bTD[nx=2] \pagearea[text] \eTD
%D     \eTR
%D     \bTR
%D       \bTD[nx=3,offset=overlay]
%D         {\bTABLE
%D            \bTR
%D              \bTD \pagearea[bottom][text][right] \eTD
%D              \bTD \pagearea[footer][text][right] \eTD
%D            \eTR
%D          \eTABLE}
%D       \eTD
%D     \eTR
%D   \eTABLE
%D \stoppagelayout
%D
%D \setupcolors[state=start]
%D
%D \setuppagenumbering[alternative=doublesided,location=]
%D
%D \setuplayout[alternative=makeup]
%D
%D \definetextbackground
%D   [test]
%D   [state=start,
%D    background=color,
%D    backgroundcolor=yellow]
%D
%D \starttext
%D
%D \dorecurse{10}{\input tufte \par}
%D
%D \input tufte \starttest \input tufte \stoptest \input tufte
%D
%D \starttabulate
%D \NC test \NC \starttest \input tufte  \stoptest \NC \NR
%D \stoptabulate
%D
%D \dorecurse{10}{\input tufte \par}
%D
%D \stoptext
%D \stoptyping

\unprotect

\installcorenamespace{layoutmakeupalternative}

\def\page_boxes_construct_content_makeup#1#2#3% targetbox flusher box
  {\setbox#1\hbox
     {\vbox to \textheight
        {\offinterlineskip
         \vskip\dimexpr-1\topskip+\strutheight\relax % could be an option
         \textwidth\makeupwidth
         \hsize\textwidth
         \boxmaxdepth\maxdepth
         \noindent
         \page_otr_command_package_contents#2#3}}%
   \wd#1\makeupwidth
   \ht#1\textheight
   \dp#1\zeropoint
   \hsize\paperwidth
   \vsize\paperheight
   \setbox#1\vbox{\csname\??layoutmakeupalternative\doifbothsidesoverruled\v!page\v!rightpage\v!leftpage\endcsname}%
   \wd#1\paperwidth
   \ht#1\paperheight
   \dp#1\zeropoint}

\installlayoutalternative\v!makeup{\page_boxes_construct_content_makeup}

\newbox\b_page_area

\unexpanded\def\pagearea
  {\dotripleempty\page_area}

\def\page_area
  {\ifthirdargument
     \expandafter\page_area_three
   \else\ifsecondargument
     \doubleexpandafter\page_area_two
   \else
     \doubleexpandafter\page_area_one
   \fi\fi}

\def\page_area_three[#1][#2][#3]%
  {\edef\m_page_area_three{#3}%
   \ifx\m_page_area_three\v!left
     \let\m_page_area_three\c!lefttext
   \else\ifx\m_page_area_three\v!right
     \let\m_page_area_three\c!righttext
   \else
     \let\m_page_area_three\c!middletext
   \fi\fi
   \page_area_indeed{#1}{#2}\m_page_area_three}

\def\page_area_two[#1][#2][#3]%
  {\edef\m_page_area_three{\doifbothsidesoverruled\c!righttext\c!righttext\c!lefttext}%
   \page_area_indeed{#1}{#2}\m_page_area_three}

\def\page_area_one[#1][#2][#3]%
  {\edef\m_page_area_one{#1}
   \ifx\m_page_area_one\v!text % copy due to trial runs in TABLE
     \iftrialtypesetting
       \fakebox\pagebox
     \else
       \page_backgrounds_add_to_text\pagebox
       \page_grids_add_to_box\pagebox
       \box\pagebox
     \fi
   \fi}

\def\page_area_indeed#1#2#3%
  {\setbox\b_page_area\vbox{\getspecificlayouttext{#1}{#2}{#3}}%
   \iftrialtypesetting
     \fakebox\b_page_area
   \else\ifcsname\??layoutbackgrounds#1#2\endcsname
     \page_area_indeed_yes{#1}{#2}%
   \else
     \box\b_page_area
   \fi\fi}

\def\page_area_indeed_yes#1#2%
  {% todo: \localbackgroundframed{\??layoutbackgrounds#1#2}{#1:#2}
   \localframed % todo:
     [\??layoutbackgrounds#1#2]
     [\c!width=\wd\b_page_area,
      \c!height=\ht\b_page_area,
      \c!offset=\v!overlay]
     {\box\b_page_area}}

% to be done nicely (proper namespacing)

\setvalue{\??layoutmakeupalternative\v!leftpage }{\csname\??layoutmakeupalternative\v!page\endcsname}
\setvalue{\??layoutmakeupalternative\v!rightpage}{\csname\??layoutmakeupalternative\v!page\endcsname}

\unexpanded\def\startpagelayout
  {\bgroup
   \catcode\endoflineasciicode\ignorecatcode
   \page_layouts_start_layout}

\let\stoppagelayout\relax

\def\page_layouts_start_layout[#1]#2\stoppagelayout
  {\egroup
   \setvalue{\??layoutmakeupalternative#1}{#2}}

\protect \endinput