%D \module
%D   [       file=strc-ren,
%D        version=2008.10.20,
%D          title=\CONTEXT\ Structure Macros,
%D       subtitle=Section Rendering,
%D         author=Hans Hagen,
%D           date=\currentdate,
%D      copyright=PRAGMA-ADE / Hans Hagen]
%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 Structure Macros / Section Rendering}

\unprotect

\chardef\headtimingmode=0

% \chardef\headtimingmode=1 % 0 also works ok now too
%
% Martin Kolarik's problem:
%
% \setuphead[section][command=\doTitle]
% \def\doTitle#1#2{\ruledvbox{\forgetall \hsize=4cm \ruledhbox{\ruledvtop{#1}\ruledvtop{#2}}}}
% \section{test test test test test test test test test test test test test test test test test}

\newevery \everyheadstart \relax

\unexpanded\def\placeheadmargintexts
  {\the\everyheadstart
   \doif{\structureheadparameter\c!margintext}\v!yes\placemargincontent}

\unexpanded\def\setupheadcomponentfont#1#2%
  {\ifconditional\structureheadisdisplay
     \edef\askedstructureheadinterlinespace{\structureheadparameter\c!interlinespace}%
     \ifx\askedstructureheadinterlinespace\empty
       % here the interline space is only set when style sets no space
       \setfalse\fontattributeisset
       \setfalse\interlinespaceisset
       \dosetstructureheadattributes\c!style\c!color
       \ifconditional\fontattributeisset \ifconditional\interlinespaceisset \else
         \setupinterlinespace
       \fi \fi
       \setfalse\fontattributeisset \dosetstructureheadattributes#1#2%
       \ifconditional\fontattributeisset \ifconditional\interlinespaceisset \else
         \setupinterlinespace
       \fi \fi
     \else
       % here the set interline space overloads any other set space in the style
       \setfalse\fontattributeisset
       \dosetstructureheadattributes\c!style\c!color
       \ifconditional\fontattributeisset
         \dosetupcheckedinterlinespace\askedstructureheadinterlinespace
       \fi
       \setfalse\fontattributeisset
       \dosetstructureheadattributes#1#2%
       \ifconditional\fontattributeisset
         \dosetupcheckedinterlinespace\askedstructureheadinterlinespace
       \fi
     \fi
   \else
     \setfalse\fontattributeisset
     \dosetstructureheadattributes\c!style\c!color
     \ifconditional\fontattributeisset
       \setupspacing
     \fi
     \setfalse\fontattributeisset
     \dosetstructureheadattributes#1#2%
     \ifconditional\fontattributeisset
       \setupspacing
     \fi
   \fi
   \dontconvertfont}

\def\doplaceheadtextcomponent#1#2%
  {\begingroup
     \setupheadcomponentfont\c!textstyle\c!textcolor
     % \ifcase\headtimingmode#1\fi % can introduce cr
     \structureheadparameter\c!commandbefore
     \placeheadmargintexts
     \ifconditional\structureheadisdisplay % \ifdisplaysectionhead
       \structureheadparameter\c!textcommand% struts can be nilled with \setnostrut
         {\setstrut
          \begstrut
          \ifcase\headtimingmode\hbox{#1}\fi
          \executeifdefined{\??nh\currentstructurehead\c!deeptextcommand}\firstofoneargument{#2}%
          \endstrut}% \hbox prevents break
       \xdef\localheadheight    {\the\strutht}%
       \xdef\localheaddepth     {\the\strutdp}%
       \xdef\localheadlineheight{\the\lineheight}%
       % == \globallet\localheaddepth\strutdepth
     \else
       \ifcase\headtimingmode#1\fi
       \structureheadparameter\c!textcommand
          {\executeifdefined{\??nh\currentstructurehead\c!deeptextcommand}\firstofoneargument{#2}}%
     \fi
     \structureheadparameter\c!commandafter
     \ifconditional\structureheadisdisplay % \ifdisplaysectionhead
       \endgraf
     \fi
   \endgroup}

\def\doplaceheadnumbercomponent#1#2%
  {\begingroup
     \setupheadcomponentfont\c!numberstyle\c!numbercolor
     % \getvalue{\??ko\currentstructurehead\c!commandbefore}% strange, why here? moved 21/11/2005
     \placeheadmargintexts
     \ifconditional\structureheadisdisplay % \ifdisplaysectionhead
       % can be nilled with \setnostrut
       \structureheadparameter\c!numbercommand
         {\setstrut
          \begstrut
          \executeifdefined{\??nh\currentstructurehead\c!deepnumbercommand}\firstofoneargument{#2}%
          \endstrut}%
     \else
       \structureheadparameter\c!numbercommand
         {\executeifdefined{\??nh\currentstructurehead\c!deepnumbercommand}\firstofoneargument{#2}}%
     \fi
   \endgroup}

% \newif\ifheadnumbercontent
% \newif\ifemptyhead
% \newif\ifdisplaysectionhead

\def\structureheadattribute{\iflocation attr \destinationattribute \currentstructureattribute\fi}

\def\doplacestructureheadtext#1#2#3% nodes, text, endstuff
  {\beginheadplacement
   \doresettructureheadnumbercontent
   \ifconditional\structureheadleaveempty
     \setbox\sectionheadbox\ifvertical\vbox\else\hbox\fi \structureheadattribute to \zeropoint {#1}%
     \makestrutofbox\sectionheadbox
   \else
     \setbox\sectionheadbox\ifvertical\vbox\else\hbox\fi \structureheadattribute
       {\doresettructureheadnumbercontent
        \ifcase\headtimingmode\or#1\fi                          % outerside font determines distance
        \dosetfontattribute{\??nh\currentstructurehead}\c!style % but we don't want color to influence user command, todo: get the if-else out of it
        \structureheadparameter\c!command{}{\doplaceheadtextcomponent{#1}{#2}}}%
   \fi
   \endheadplacement{#3}}

\def\doplacestructureheadnumbertext#1#2#3#4% nodes number text nodes
  {\beginheadplacement
   \doiftextelse{#2}\dosettructureheadnumbercontent\doresettructureheadnumbercontent
   \ifconditional\structureheadleaveempty
     \setbox\sectionheadbox\ifvertical\vbox\else\hbox\fi \structureheadattribute to \zeropoint{#1}%
     \makestrutofbox\sectionheadbox
   \else % = needed
     \setbox\sectionheadbox\ifvertical\vbox\else\hbox\fi \structureheadattribute
       {\ifcase\headtimingmode\or#1\fi
        \dosetfontattribute{\??nh\currentstructurehead}\c!style
        \structureheadparameter\c!command{\doplaceheadnumbercomponent{#1}{#2}}{\doplaceheadtextcomponent{#1}{#3}}}%
   \fi
   \endheadplacement{#4}}

\unexpanded\def\placestructureheadnumbertext
  {\doplacestructureheadnumbertext\empty\getstructureheadnumber\getstructureheadtitle\getstructureheadsyncs}

\unexpanded\def\placestructureheadtext
  {\doplacestructureheadtext\empty\getstructureheadtitle\getstructureheadsyncs}

\unexpanded\def\placestructureheadempty
  {\hbox \structureheadattribute {\getstructureheadsyncs}}

%D \starttyping
%D \def\StretchedBox#1%
%D   {\framed
%D      [frame=off,offset=.5em,align=middle,width=broad]
%D      {\sc\def\stretchedspaceamount{.3em}\stretchednormalcase{#1}}}
%D
%D \definehead[MySubject][subject]
%D \setuphead [MySubject][deeptextcommand=\StretchedBox]
%D
%D \MySubject{feeling stretched feeling stretched feeling stretched feeling stretched}
%D \stoptyping

\let\headlastlinewidth\!!zeropoint

\def\localheadheight    {\strutht}
\def\localheaddepth     {\strutdp}
\def\localheadlineheight{\lineheight}

\def\dolocalheadsetup  %  koppeling met standaard kopcommando / engels
  {\forgetall          %  traag dus ...
   \doifsomething{\structureheadparameter\c!align    }     {\normalexpanded{\noexpand\setupalign    [\structureheadparameter\c!align    ]}}%
   \doifsomething{\structureheadparameter\c!tolerance}     {\normalexpanded{\noexpand\setuptolerance[\structureheadparameter\c!tolerance]}}%
   \doif         {\structureheadparameter\c!strut    }\v!no{\setnostrut}% new
   \def\\{\crlf\strut\ignorespaces}}

\def\beginheadplacement
  {\bgroup
   \setsystemmode\currentstructurehead
   \xdef\localheadheight    {\the\strutht}%
   \xdef\localheaddepth     {\the\strutdp}%
   \xdef\localheadlineheight{\the\lineheight}%
   % == \globallet\localheaddepth\strutdp
   \everypar\emptytoks % needed indeed
   \noindent           % ipv \whitespace elders, na \forgetall !
   \bgroup
   \doifinsetelse{\structureheadparameter\c!aligntitle}{\v!yes,\v!float}% new
     {\skip0 1\leftskip
      \skip2 1\rightskip
      \xdef\localheadskip{\the\skip0}%
      \forgetall
      \leftskip\skip0
      \rightskip\skip2
      \setlocalhsize\hsize\localhsize
      \forgetbothskips}
     {\globallet\localheadskip\!!zeropoint
      \forgetall}%
   \dontcomplain
   \postponenotes
   \iflocation
     \ifconditional\structureheadisdisplay % \ifdisplaysectionhead
     \else
       \noninterferingmarks
     \fi
   \fi
   \resetinteractionparameter\c!style
   \resetinteractionparameter\c!color
   \resetinteractionparameter\c!contrastcolor
   %\strictouterreferencestrue % tzt instelling
   \let\localheadsetup\dolocalheadsetup}

% \setuphead[chapter]         [style=\bfd,after=,hang=line] % fit broad 2
% \setuphead[section]         [style=\bfc,after=,hang=line]
% \setuphead[subsection]      [style=\bfb,after=,hang=line]
% \setuphead[subsubsection]   [style=\bfa,after=,hang=line]
% \setuphead[subsubsubsection][style=\bf ,after=,hang=line]
%
% \chapter         {Test} \input tufte \page
% \section         {Test} \input tufte \page
% \subsection      {Test} \input tufte \page
% \subsubsection   {Test} \input tufte \page
% \subsubsubsection{Test} \input tufte \page
%
% \chapter         {Test\\Test} \input tufte \page
% \section         {Test\\Test} \input tufte \page
% \subsection      {Test\\Test} \input tufte \page
% \subsubsection   {Test\\Test} \input tufte \page
% \subsubsubsection{Test\\Test} \input tufte \page

\def\hangheadplacement
  {\scratchdimen\localheadlineheight
   \bgroup
   \openlineheight\scratchdimen
   \scratchdimen\htdp0%
   \getnoflines\scratchdimen
   \advance\noflines\minusone
   \normalexpanded{\egroup\noflines\the\noflines}% brrr
   \setbox0\hbox{\lower\noflines\scratchdimen\box0}%
   \scratchdimen\dimexpr\htdp0-\localheadheight+\strutdp\relax
   \ht0 \strutht
   \dp0 \strutdp
   \edef\localheaddepth{\the\strutdp}}

\newconditional\continuoussectionhead % oeps, \newif\ifcontinuoushead got lost
\newbox\sectionheadbox

\def\endheadplacement#1%
  {\noflines\zerocount
   \ifconditional\structureheadisdisplay % \ifdisplaysectionhead
     % new (todo tight == one following line up)
     \processaction
       [\structureheadparameter\c!hang]
       [    \v!line=>\hangheadplacement\noflines\zerocount,
           \v!broad=>\hangheadplacement\getnoflines\scratchdimen,
             \v!fit=>\hangheadplacement\getrawnoflines\scratchdimen,
            \v!none=>\noflines\zerocount,
         \v!default=>\noflines\zerocount,
         \v!unknown=>\hangheadplacement\noflines\numexpr0\commalistelement-1\relax]%
     % so far
     \let\headlastlinewidth\!!zeropoint
     % kind of special, we want to snap heads also according to local specs local
     \ifgridsnapping
       \begingroup
       \edef\currentstructureheadgridsnapping{\structureheadparameter\c!grid}%
       \ifconditional\structureheadisdisplay
         \ifx\currentstructureheadgridsnapping\empty\else
           \dosetstructureheadattributes\c!style\c!color
           \setupinterlinespace
           \dosetstructureheadattributes\c!textstyle\c!textcolor
           \setupinterlinespace
         \fi
       \fi
       \snaptogrid[\currentstructureheadgridsnapping]\hbox
         {\hskip\localheadskip\hskip\structureheadparameter\c!margin\box\sectionheadbox}%
       \endgroup
     \else
       \hbox
         {\hskip\localheadskip\hskip\structureheadparameter\c!margin\box\sectionheadbox}%
     \fi
     \flushnotes % new, not really needed
     \endgraf
     \ifvmode
       \ifnum\noflines>\zerocount
         \dorecurse\noflines{\nointerlineskip\dosomebreak\nobreak\strut\endgraf}% to be checked
       \fi
       \nointerlineskip
       \dosomebreak\nobreak
     \fi
     #1%
   \else
     \strut
     \flushnotes % new, here since we're in par mode
     \unhbox\sectionheadbox
     \globallet\headlastlinewidth\!!zeropoint
     #1%
     \hskip\numberheaddistance\!!plus\numberheaddistance\!!minus.25\dimexpr\numberheaddistance\relax
     \hskip\continuousstructureheadsignal\ignorespaces
   \fi
   \ifconditional\structureheadisdisplay % \ifdisplaysectionhead
     \ifvmode
       \ifgridsnapping % important, font related depth, see comment
         \prevdepth\strutdp
       \else
         \prevdepth\localheaddepth
       \fi
     \fi
   \fi
   \egroup
   \egroup
   \ifconditional\structureheadisdisplay % \ifdisplaysectionhead
     \checknextindentation[\structureheadparameter\c!indentnext]%
   \else
     \nonoindentation % recently added, was a bug
   \fi}

% nice testcase
%
% \setupheads[aligntitle=yes]
%
% \startnarrower
%   \subject{\dorecurse{100}{x }}
%   \section{\dorecurse{100}{x }}
%   \input tufte \par
%   \setupheads[alternative=inmargin]
%   \subject{\dorecurse{100}{x }}
%   \section{\dorecurse{100}{x }}
%   \input tufte \par
% \stopnarrower

\let\numberheadalternative\v!normal

\unexpanded\def\defineheadplacement
  {\dodoubleargument\dodefineheadplacement}

\def\dodefineheadplacement[#1][#2]% #3#4
  {\setvalue{\??ns:#1}{#2}%
   \setvalue{\??ns::#1}}

\def\presetnumberheadalternative
  {\doifelsevalue{\??ns:\numberheadalternative}\v!horizontal\setfalse\settrue\structureheadisdisplay}

% \def\normalplacehead
%   {\executeifdefined
%      {\??ns::\numberheadalternative}
%      {\getvalue{\??ns::\v!normal}}}

\def\normalplacehead
  {\csname\??ns::\ifcsname\??ns::\numberheadalternative\endcsname\numberheadalternative\else\v!normal\fi\endcsname}

\defineheadplacement[\v!paragraph][\v!vertical]#1#2%
  {\vbox
     {\localheadsetup
      \begstrut
      \ifconditional\structureheadshownumber % \ifheadnumbercontent
        #1\hskip\numberheaddistance
      \fi
      #2}}

% \defineheadplacement[\v!normal][\v!vertical]#1#2%
%   {\ifconditional\structureheadshownumber % \ifheadnumbercontent
%      \setbox0\hbox{{#1}\hskip\numberheaddistance}%
%      \vbox
%        {\localheadsetup
%         \hangindent 1\wd0
%         \hangafter 1
%         \noindent
%         \unhbox0    %  don't use \strut's here!
%         #2}%
%    \else
%      \vbox
%        {\localheadsetup\noindent#2}%
%    \fi}
%
% enhanced version:

% \setuphead
%   [chapter]
%   [numberwidth=2cm,hang=line,after={\blank[3*line]}]
%
% \chapter{Oeps oeps oeps} \input tufte   \section{Oeps}
% \chapter{Oeps oeps oeps} \section{Oeps} \input tufte

\defineheadplacement[\v!normal][\v!vertical]#1#2%
  {\vbox
     {\localheadsetup
      \edef\headwidth      {\structureheadparameter\c!width      }%
      \edef\headnumberwidth{\structureheadparameter\c!numberwidth}%
      \edef\headtextwidth  {\structureheadparameter\c!textwidth  }%
      \ifconditional\structureheadshownumber % \ifheadnumbercontent
        \ifx\headwidth\empty
        \else
          \ifx\headnumberwidth\empty
            \ifx\headtextwidth\empty\else
              \edef\headnumberwidth{\the\dimexpr\headwidth-\headtextwidth\relax}%
            \fi
          \else
            \ifx\headtextwidth\empty
              \edef\headtextwidth{\the\dimexpr\headwidth-\headnumberwidth\relax}%
            \fi
          \fi
          \hsize\headwidth
        \fi
        \ifx\headnumberwidth\empty\else
          \let\numberheaddistance\!!zeropoint
        \fi
        \setbox\scratchbox\hbox \ifx\headnumberwidth\empty\else to \headnumberwidth\fi{{#1}}%
        \scratchdimen\dimexpr\wd\scratchbox+\numberheaddistance\relax
        \ifx\headtextwidth\empty\else
          \hsize\dimexpr\scratchdimen+\headparameter\c!textwidth\relax
        \fi
        \hangindent\scratchdimen
        \hangafter \plusone
        \noindent
        \box\scratchbox\hskip\numberheaddistance
      \else
        \ifx\headtextwidth\empty
          \ifx\headwidth\empty
          \else
            \hsize\headwidth
          \fi
        \else
          \hsize\headtextwidth
        \fi
        \noindent
      \fi
      #2}}

\unexpanded\def\placeheadmargin#1#2%
  {\vbox
     {\localheadsetup
      \begstrut % use one \strut here!
      \dontleavehmode % in case there is no strut, else side effects with llap
      \ifconditional\structureheadshownumber % \ifheadnumbercontent
        \llap{\hbox to 5em{\hfill{#1}\hskip\localheadskip\hskip\leftmargindistance}}% introduces whitespace
        % maybe better:
        % \inleftmargin{\hbox{\hss{#1}\hskip\localheadskip}}%
      \fi
      {#2}}}

\defineheadplacement[\v!inmargin][\v!vertical]#1#2{\placeheadmargin{#1}{#2}}
\defineheadplacement[\v!margin]  [\v!vertical]#1#2{\placeheadmargin{#1}{#2}}

\defineheadplacement[\v!middle][\v!vertical]#1#2%
  {\vbox
     {\localheadsetup
      \veryraggedcenter
      \let\\\endgraf
      \let\crlf\endgraf
      \ifconditional\structureheadshownumber % \ifheadnumbercontent
        \strut#1\par
      \fi
      \begstrut#2}}

\defineheadplacement[\v!text][\v!horizontal]#1#2%
  {\bgroup
   \localheadsetup % no stretch in distance
   \ifconditional\structureheadshownumber % \ifheadnumbercontent
     {#1}\kern\numberheaddistance
   \fi
   {\begstrut#2}%
   \egroup}

\unexpanded\def\placeheadlohi#1#2#3%
  {\ifconditional\structureheadshownumber % \ifheadnumbercontent
     \setbox0\hbox{#2}
     \setbox2=#1{\localheadsetup\advance\hsize-\wd0\relax#3}%
     \hbox{\box0\hskip\numberheaddistance\box2}%
   \else
     #1{\localheadsetup\noindent#3}%
   \fi}

% onder/boven lijnt het nummer op de onderste/bovenste regel
% uit van een meerregelige kop

\defineheadplacement[\v!bottom][\v!vertical]#1#2{\placeheadlohi\vbox{#1}{#2}}
\defineheadplacement[\v!top]   [\v!vertical]#1#2{\placeheadlohi\vtop{#1}{#2}}

\protect \endinput