path: root/tex/context/base/strc-ren.mkiv

%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 \& \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 Structure Macros / Section Rendering}

\unprotect

\newbox\b_strc_rendering_head

\newdimen\d_strc_rendering_local_leftoffset
\newdimen\d_strc_rendering_local_rightoffset

% 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}

\newtoks\everyheadstart

\unexpanded\def\strc_rendering_initialize_style_and_color
  {\ifconditional\headisdisplay
     \expandafter\strc_rendering_initialize_style_and_color_display
   \else
     \expandafter\strc_rendering_initialize_style_and_color_inline
   \fi}

\unexpanded\def\strc_rendering_initialize_style_and_color_display#1#2%
  {\dontconvertfont
   \edef\p_strc_rendering_interlinespace{\headparameter\c!interlinespace}%
   \ifx\p_strc_rendering_interlinespace\empty
     % here the interline space is only set when style sets no space
     \setfalse\fontattributeisset % use the currentfontparameter state instead
     \setfalse\interlinespaceisset
     \useheadstyleandcolor\c!style\c!color\relax
     \ifconditional\fontattributeisset \ifconditional\interlinespaceisset \else
       \setupinterlinespace
     \fi \fi
     \setfalse\fontattributeisset
     \useheadstyleandcolor#1#2\relax
     \ifconditional\fontattributeisset \ifconditional\interlinespaceisset \else
       \setupinterlinespace
     \fi \fi
   \else
     % here the set interline space overloads any other set space in the style
     \setfalse\fontattributeisset
     \useheadstyleandcolor\c!style\c!color\relax
     \ifconditional\fontattributeisset
       \dosetupcheckedinterlinespace\p_strc_rendering_interlinespace
     \fi
     \setfalse\fontattributeisset
     \useheadstyleandcolor#1#2\relax
     \ifconditional\fontattributeisset
       \dosetupcheckedinterlinespace\p_strc_rendering_interlinespace
     \fi
   \fi}

\unexpanded\def\strc_rendering_initialize_style_and_color_inline#1#2%
   {\dontconvertfont
    \setfalse\fontattributeisset
    \useheadstyleandcolor\c!style\c!color\relax
    \ifconditional\fontattributeisset
      \updateraggedskips % \setupspacing
    \fi
    \setfalse\fontattributeisset
    \useheadstyleandcolor#1#2\relax
    \ifconditional\fontattributeisset
      \updateraggedskips % \setupspacing
    \fi}

\let\currentstructurereferenceattribute\attributeunsetvalue

\def\headreferenceattributes
  {\iflocation
   % \ctxlua{structures.lists.taglocation(\nextinternalreference)}% maybe ... tags entry as used
     attr \destinationattribute \currentstructureattribute
     attr \referenceattribute   \currentstructurereferenceattribute
   % attr \internalattribute    \nextinternalreference
   \fi}

\def\setinlineheadreferenceattributes
  {\ifconditional\headisdisplay \else \iflocation
     \attribute\destinationattribute\currentstructureattribute
     \attribute\referenceattribute  \currentstructurereferenceattribute
   % \attribute\internalattribute   \nextinternalreference
   \fi \fi}

\def\docheckheadreference
  {\edef\currentheadinteraction{\headparameter\c!interaction}%
   \ifx\currentheadinteraction\v!list
     % setuphead[<section>][interaction=list,...]
     \strc_references_get_simple_page_reference{bck:\nextinternalreference}%
     \let\currentstructurereferenceattribute\currentreferenceattribute
   \else\ifx\currentheadinteraction\v!reference
     % setuphead[<section>][interaction=reference,...] start<section>[backreference=abc,...]
     \edef\currentheadbackreference{\structurevariable\c!backreference}% weird, was references.backreference
     \ifx\currentheadbackreference\empty \else
       \strc_references_get_simple_page_reference\currentheadbackreference
       \let\currentstructurereferenceattribute\currentreferenceattribute
     \fi
   \else
      % maybe auto: backreference when given, else list
   \fi\fi}

% a bit messy ... empty in place instead of self .. might change (or use special
% whatsig (invisible user one)

\unexpanded\def\strc_rendering_place_head_text
  {\strc_rendering_start_placement
   \setheadmarking
   \doresettructureheadnumbercontent
   \ifconditional\c_strc_sectioning_empty
     \setbox\b_strc_rendering_head\hbox \headreferenceattributes to \zeropoint{\strut}%
   \else
     \docheckheadreference
     \setbox\b_strc_rendering_head\hbox \headreferenceattributes
       {\spac_grids_set_local_snapping{\headparameter\c!internalgrid}%
        \doresettructureheadnumbercontent
        \useheadstyleparameter\c!style
        \setinlineheadreferenceattributes
        \strc_rendering_inject_text}%
   \fi
   \strc_rendering_stop_placement}

\unexpanded\def\strc_rendering_place_head_number_and_text
  {\strc_rendering_start_placement
   \setheadmarking
   \doiftextelse\getheadnumber
     \dosettructureheadnumbercontent
     \doresettructureheadnumbercontent
   \ifconditional\c_strc_sectioning_empty
     \setbox\b_strc_rendering_head\hbox \headreferenceattributes to \zeropoint{\strut}%
   \else % = needed
     \docheckheadreference
     \setbox\b_strc_rendering_head\hbox \headreferenceattributes
       {\spac_grids_set_local_snapping{\headparameter\c!internalgrid}%
        \useheadstyleparameter\c!style
        \setinlineheadreferenceattributes
        \strc_rendering_inject_number_and_text}%
   \fi
   \strc_rendering_stop_placement}

\unexpanded\def\strc_rendering_place_head_empty
  {\hbox \headreferenceattributes {\getheadsyncs}}

%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

% helpers

% \defineinmargin [ChapterInMargin] [outer] [normal] [distance=0.3em]
%
% \defineheadplacement[MyTest][horizontal]#1#2%
%   {\startlocalheadsetup
%   %\ChapterInMargin{\headhbox{\strut#2}}% proper destination, ref okay
%    \ChapterInMargin{\strut#2}% zero destination, ref okay
%    \stoplocalheadsetup}
%
% \setuphead
%   [chapter]
%   [alternative=MyTest]

\unexpanded\def\headhbox{\hbox\headreferenceattributes}
\unexpanded\def\headvbox{\vbox\headreferenceattributes}

\unexpanded\def\startlocalheadsetup{\bgroup\strc_rendering_initialize_spacing}
\unexpanded\def\stoplocalheadsetup {\egroup}

\unexpanded\def\strc_rendering_initialize_spacing
  {\forgetall % local !
   \edef\p_align{\headparameter\c!align}%
   \ifx\p_align\empty \else
     \setupalign[\p_align]%
   \fi
   \edef\p_tolerance{\headparameter\c!tolerance}%
   \ifx\p_tolerance\empty \else
     \setuptolerance[\p_tolerance]%
   \fi
   \edef\p_strut{\headparameter\c!strut}%
   \ifx\p_strut\v!no
     \setnostrut
   \fi
   \let\\\strc_rendering_shortcut_backslash}

\unexpanded\def\strc_rendering_shortcut_backslash
  {\crlf
   \strut
   \ignorespaces}

\def\strc_rendering_start_placement
  {\bgroup
   \setsystemmode\currenthead
   %
   \strc_rendering_initialize_alternatives
   \strc_rendering_initialize_dimensions
   %
   \strc_rendering_initialize_line_state
   \reseteverypar % needed indeed
   \noindent      % ipv \whitespace elders, na \forgetall !
   \bgroup
   \edef\p_aligntitle{\headparameter\c!aligntitle}%
   \ifx\p_aligntitle\v!yes
     \strc_rendering_initialize_hsize_local
   \else\ifx\p_aligntitle\v!float
     \strc_rendering_initialize_hsize_local
   \else
     \strc_rendering_initialize_hsize_global
   \fi\fi
   \setfalse\inhibitmargindata % brrrr is set in forgetall
   \dontcomplain
   \postponenotes
   \strc_rendering_initialize_interaction
   % delayed
   \let\localheadsetup  \strc_rendering_initialize_spacing % historic name
   \let\headsetupspacing\strc_rendering_initialize_spacing}

\def\strc_rendering_initialize_hsize_local
  {\global\d_strc_rendering_local_leftoffset \leftskip
   \global\d_strc_rendering_local_rightoffset\rightskip
 % \forgetall
 % \leftskip \d_strc_rendering_local_leftoffset  % no stretch
 % \rightskip\d_strc_rendering_local_rightoffset % no stretch
 % \setlocalhsize
 % \hsize\localhsize
 % \forgetbothskips}
   \scratchwidth\availablehsize
   \forgetall
   \hsize\scratchwidth}

\def\strc_rendering_initialize_hsize_global
  {\global\d_strc_rendering_local_leftoffset \zeropoint
   \global\d_strc_rendering_local_rightoffset\zeropoint
   \forgetall}

\def\strc_rendering_initialize_interaction
  {\resetinteractionparameter\c!style
   \resetinteractionparameter\c!color
   \resetinteractionparameter\c!contrastcolor}

% \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

\newdimen\d_strc_rendering_hang_height
\newcount\n_strc_rendering_hang_lines

\newdimen\d_strc_rendering_local_height
\newdimen\d_strc_rendering_local_depth
\newdimen\d_strc_rendering_local_lineheight

\def\strc_rendering_initialize_line_state
  {\global\d_strc_rendering_local_height\strutht
   \global\d_strc_rendering_local_depth\strutdp
   \global\d_strc_rendering_local_lineheight\lineheight}

\def\strc_rendering_check_hang
  {\begingroup
   \openlineheight\d_strc_rendering_local_lineheight
   \d_strc_rendering_hang_height\htdp\b_strc_rendering_head
   \getnoflines\d_strc_rendering_hang_height
   \normalexpanded{\endgroup\n_strc_rendering_hang_lines\the\numexpr\noflines-\plusone\relax}% brrr
   \setbox\b_strc_rendering_head\hbox{\lower\n_strc_rendering_hang_lines\d_strc_rendering_hang_height\box\b_strc_rendering_head}%
   \d_strc_rendering_hang_height\dimexpr\htdp\b_strc_rendering_head-\d_strc_rendering_local_height+\strutdp\relax
   \ht\b_strc_rendering_head\strutht
   \dp\b_strc_rendering_head\strutdp
   \d_strc_rendering_local_depth\strutdp}

\installcorenamespace{headplacementcheckhang}

\setvalue{\??headplacementcheckhang\v!line   }{\strc_rendering_check_hang
                                               \n_strc_rendering_hang_lines\zerocount}
\setvalue{\??headplacementcheckhang\v!broad  }{\strc_rendering_check_hang
                                               \getnoflines\d_strc_rendering_hang_height}
\setvalue{\??headplacementcheckhang\v!fit    }{\strc_rendering_check_hang
                                               \getrawnoflines\d_strc_rendering_hang_height}
\setvalue{\??headplacementcheckhang\v!none   }{\n_strc_rendering_hang_lines\zerocount}
\setvalue{\??headplacementcheckhang          }{\n_strc_rendering_hang_lines\zerocount}
\setvalue{\??headplacementcheckhang\s!unknown}{\strc_rendering_check_hang
                                               \n_strc_rendering_hang_lines\numexpr\p_hang-\plusone\relax}

\def\strc_rendering_initialize_line_hang
   {\ifconditional\headisdisplay
      \edef\p_hang{\headparameter\c!hang}%
      \expandcheckedcsname\??headplacementcheckhang\p_hang\s!unknown
      \relax
    \else
      \n_strc_rendering_hang_lines \zerocount
      \d_strc_rendering_hang_height\zeropoint
    \fi}

\def\strc_rendering_stop_placement
  {\n_strc_rendering_hang_lines\zerocount
   \ifconditional\headisdisplay
     \strc_rendering_initialize_line_hang
     % kind of special, we want to snap heads also according to local specs local
     \ifgridsnapping
       \hbox\bgroup % extra hbox will trigger global snapper on top of local
         \edef\p_grid{\headparameter\c!grid}%
         \ifconditional\headisdisplay
           \ifx\p_grid\empty\else
             \useheadstyleandcolor\c!style\c!color
             \setupinterlinespace
             \useheadstyleandcolor\c!textstyle\c!textcolor
             \setupinterlinespace
           \fi
         \fi
         \snaptogrid[\p_grid]\hbox
           {\hskip\dimexpr\d_strc_rendering_local_leftoffset+\headparameter\c!margin\relax\box\b_strc_rendering_head}%
       \egroup
     \else
       \hbox
         {\hskip\dimexpr\d_strc_rendering_local_leftoffset+\headparameter\c!margin\relax\box\b_strc_rendering_head}%
     \fi
     \flushnotes % new, not really needed
     \endgraf
     \ifvmode
       \ifnum\n_strc_rendering_hang_lines>\zerocount
         \dorecurse\n_strc_rendering_hang_lines{\nointerlineskip\dosomebreak\nobreak\strut\endgraf}% to be checked
       \fi
       \nointerlineskip
       \dosomebreak\nobreak
     \fi
     \getheadsyncs
   \else
     \strut
     \flushnotes % new, here since we're in par mode
     \unhbox\b_strc_rendering_head
     \getheadsyncs
     \hskip\headnumberdistance\!!plus\headnumberdistance\!!minus.25\dimexpr\headnumberdistance\relax
     \strc_sectioning_inject_continuous_signal
   \fi
   \ifconditional\headisdisplay
     \ifvmode
       \ifgridsnapping % important, font related depth, see comment
         \prevdepth\strutdp
       \else
         \prevdepth\d_strc_rendering_local_depth
       \fi
     \fi
   \fi
   \egroup
   \egroup
   \ifconditional\headisdisplay
     \useindentnextparameter\headparameter
   \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

% \dodefineheadplacement[sectiona][vertical]{#1->#2}
% \dodefineheadplacement[sectionb][vertical]#1#2{#1->#2}
%
% \setuphead[section][alternative=sectiona]
% \setuphead[subsection][alternative=sectionb]

% \startsetups[\??headrenderings:\v!vertical:\v!sectiona]
%     ... there will be a more public namespace
% \stopsetups

\installcorenamespace{headplacementalternative}
\installcorenamespace{headrenderings}
\installcorenamespace{headalternative}

\installcommandhandler \??headalternative {headalternative} \??headalternative % or just \??head

\setupheadalternative
  [%\c!width=\headparameter\c!width,
   %\c!distance=\headparameter\c!distance,
   \c!alternative=\v!vertical,
   \c!renderingsetup=\??headrenderings:\currentheadalternative]

\let\currentheadalternative         \v!normal
\let\currentheadrenderingsetup      \empty
\let\currentheadrenderingalternative\v!vertical

\unexpanded\def\defineheadplacement % old mechanism
  {\dodoubleargument\strc_rendering_define_placement}

\def\strc_rendering_define_placement[#1][#2]%
  {\doifnextbgroupelse
     {\strc_rendering_define_placement_yes[#1][#2]}%
     {\strc_rendering_define_placement_nop[#1][#2]}}

\def\strc_rendering_define_placement_yes[#1][#2]%
  {\defineheadalternative[#1][\c!alternative=#2,\c!renderingsetup=\??headrenderings:\v!command]%
   \setuvalue{\??headplacementalternative#1}##1##2}

\def\strc_rendering_define_placement_nop[#1][#2]%
  {\defineheadalternative[#1][\c!alternative=#2,\c!renderingsetup=\??headrenderings:\v!command]%
   \setuvalue{\??headplacementalternative#1}}

% these can be used in setups:
%
% \headnumbercontent
% \headtextcontent
%
% \headwidth
% \headtextwidth
% \headnumberdistance
% \headnumberwidth
% \headsetupspacing
%
% \headshownumber
% \headisdisplay

\let\headnumbercontent\empty
\let\headtextcontent  \empty

\newdimen\headwidth
\newdimen\headtextwidth
\newdimen\headnumberdistance
\newdimen\headnumberwidth

% \newconditional\headshownumber % defined already
% \newconditional\headisdisplay  % defined already

\unexpanded\def\strc_rendering_initialize_alternatives
  {\edef\currentheadalternative         {\headparameter           \c!alternative}%
   \edef\currentheadrenderingsetup      {\headalternativeparameter\c!renderingsetup}%
   \edef\currentheadrenderingalternative{\headalternativeparameter\c!alternative}%
   \ifx\currentheadrenderingalternative\empty
     \let\currentheadrenderingalternative\v!vertical
   \fi
   \ifx\currentheadrenderingalternative\v!horizontal
     \global\setfalse\headisdisplay % global
   \else
     \global\settrue\headisdisplay  % global
   \fi}

\unexpanded\def\strc_rendering_initialize_dimensions
  {\headwidth         \headparameter\c!width      \relax  % \zeropoint == unset
   \headnumberwidth   \headparameter\c!numberwidth\relax  % \zeropoint == unset
   \headnumberdistance\headparameter\c!distance   \relax
   \headtextwidth     \headparameter\c!textwidth  \relax} % \zeropoint == unset

\unexpanded\def\headtextcontent
  {\begingroup
     \strc_rendering_initialize_style_and_color\c!textstyle\c!textcolor
     \headparameter\c!commandbefore\relax
     \ifcsname\currentheadhash\c!deeptextcommand\endcsname
       \expandafter\let\expandafter\deepstructuretitlecommand\csname\currentheadhash\c!deeptextcommand\endcsname
     \fi
     \ifconditional\headisdisplay
       % struts can be nilled with \setnostrut
       \headparameter\c!textcommand{\setstrut\begstrut\getheadtitle\endstrut}%
       \global\d_strc_rendering_local_height\strutht
       \global\d_strc_rendering_local_depth\strutdp
       \global\d_strc_rendering_local_lineheight\lineheight
       \headparameter\c!commandafter\relax
       \endgraf
     \else
       \headparameter\c!textcommand{\getheadtitle}%
       \headparameter\c!commandafter\relax
     \fi
   \endgroup}

\unexpanded\def\headnumbercontent
  {\begingroup
     \strc_rendering_initialize_style_and_color\c!numberstyle\c!numbercolor
     \ifcsname\currentheadhash\c!deepnumbercommand\endcsname
       \expandafter\let\expandafter\deepstructurenumbercommand\csname\currentheadhash\c!deepnumbercommand\endcsname
     \fi
     \ifconditional\headisdisplay
       % can be nilled with \setnostrut
       \headparameter\c!numbercommand{\setstrut\begstrut\getheadnumber\endstrut}%
     \else
       \headparameter\c!numbercommand{\getheadnumber}%
     \fi
   \endgroup}

\unexpanded\def\strc_rendering_inject_number_and_text
  {\edef\p_command{\headparameter\c!command}% assumes \unexpanded definition
   \ifx\p_command\empty
     \directsetup\currentheadrenderingsetup
   \else
     \p_command\headnumbercontent\headtextcontent
   \fi}

\unexpanded\def\strc_rendering_inject_text
  {\edef\p_command{\headparameter\c!command}% assumes \unexpanded definition
   \ifx\p_command\empty
     \directsetup\currentheadrenderingsetup
   \else
     \p_command\empty\headtextcontent
   \fi}

\startsetups[\??headrenderings:\v!command]
    \csname\??headplacementalternative\currentheadalternative\endcsname \headnumbercontent \headtextcontent
\stopsetups

% obsolete
%
% \def\normalplacehead % hooks into \c!command
%   {\csname\??headplacementalternative\ifcsname\??headplacementalternative\currentheadalternative\endcsname\currentheadalternative\else\v!normal\fi\endcsname}

\defineheadalternative
  [\v!paragraph]
  [\c!alternative=\v!vertical,
   \c!renderingsetup=\??headrenderings:\v!paragraph]

\startsetups[\??headrenderings:\v!paragraph]
    \vbox {
        \headsetupspacing
        \begstrut
        \ifconditional\headshownumber % \ifheadnumbercontent
            \headnumbercontent
            \hskip\headnumberdistance
        \fi
        \headtextcontent
    }
\stopsetups

% \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

\defineheadalternative
  [\v!normal]
  [\c!alternative=\v!vertical,
   \c!renderingsetup=\??headrenderings:\v!normal]

\startsetups[\??headrenderings:\v!normal]
    \vbox {
        \headsetupspacing
        \ifconditional\headshownumber
            \ifdim\headwidth=\zeropoint \else
                \ifdim\headnumberwidth=\zeropoint
                    \ifdim\headtextwidth=\zeropoint \else
                        \headnumberwidth\dimexpr\headwidth-\headtextwidth\relax
                    \fi
                \else
                    \ifdim\headtextwidth=\zeropoint
                        \headtextwidth\dimexpr\headwidth-\headnumberwidth\relax
                    \fi
                \fi
                \hsize\headwidth
            \fi
            \ifdim\headnumberwidth=\zeropoint\else
                \headnumberdistance\zeropoint
            \fi
            \setbox\scratchbox\hbox \ifdim\headnumberwidth=\zeropoint\else to \headnumberwidth\fi{\headnumbercontent}
            \scratchdimen\dimexpr\wd\scratchbox+\headnumberdistance\relax
            \ifdim\headtextwidth=\zeropoint\else
                \hsize\dimexpr\scratchdimen+\headtextwidth\relax
            \fi
            \hangindent\scratchdimen
            \hangafter \plusone
            \noindent
            \box\scratchbox
            \hskip\headnumberdistance
        \else
            \ifdim\headtextwidth=\zeropoint
                \ifdim\headwidth=\zeropoint \else
                    \hsize\headwidth
                \fi
            \else
                \hsize\headtextwidth
            \fi
            \noindent
        \fi
        \headtextcontent
    }
\stopsetups

\defineheadalternative
  [\v!inmargin]
  [\c!alternative=\v!vertical,
   \c!renderingsetup=\??headrenderings:\v!inmargin]

\startsetups[\??headrenderings:\v!inmargin]
    \vbox {
        \headsetupspacing
        \begstrut % use one \strut here!
        \dontleavehmode % in case there is no strut, else side effects with llap
        \ifconditional\headshownumber
            \llap {
                \hbox {
                    \hfill
                    \headnumbercontent
                    \hskip\dimexpr\d_strc_rendering_local_leftoffset+\doifoddpageelse\leftmargindistance\rightmargindistance\relax
                }
            }
        \fi
        \headtextcontent
    }
\stopsetups

\defineheadalternative
  [\v!margin]
  [\v!inmargin]

% \startsetups[\??headrenderings:\v!vertical:\v!margin]
%     \directsetup{\??headrenderings:\v!vertical:\v!inmargin}
% \stopsetups

\defineheadalternative
  [\v!middle]
  [\c!alternative=\v!vertical,
   \c!renderingsetup=\??headrenderings:\v!middle]

\startsetups[\??headrenderings:\v!middle]
    \vbox {
        \headsetupspacing
        \veryraggedcenter
        \let\\\endgraf
        \let\crlf\endgraf
        \ifconditional\headshownumber
            \strut
            \headnumbercontent
            \par
        \fi
        \begstrut
        \headtextcontent
        \endstrut
    }
\stopsetups

\defineheadalternative
  [\v!text]
  [\c!alternative=\v!horizontal,
   \c!renderingsetup=\??headrenderings:\v!text]

\startsetups[\??headrenderings:\v!text]
    \begingroup
    \headsetupspacing % no stretch in distance
    \ifconditional\headshownumber
        \headnumbercontent
        \kern\headnumberdistance
    \fi
    \begstrut
    \headtextcontent
    \endstrut
    \endgroup
\stopsetups

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

\defineheadalternative
  [\v!bottom]
  [\c!alternative=\v!vertical,
   \c!renderingsetup=\??headrenderings:\v!bottom]

\startsetups[\??headrenderings:\v!bottom]
    \ifconditional\headshownumber
        \setbox0\hbox {
            \headnumbercontent
        }
        \setbox2\vbox {
            \headsetupspacing
            \advance\hsize-\wd0\relax
            \headtextcontent
        }
        \hbox {
            \box0
            \hskip\headnumberdistance
            \box2
        }
    \else
        \vbox {
            \headsetupspacing
            \noindent
            \headtextcontent
        }
    \fi
\stopsetups

\defineheadalternative
  [\v!top]
  [\c!alternative=\v!vertical,
   \c!renderingsetup=\??headrenderings:\v!top]

\startsetups[\??headrenderings:\v!top]
    \ifconditional\headshownumber
        \setbox0\hbox {
            \headnumbercontent
        }
        \setbox2\vtop {
            \headsetupspacing
            \advance\hsize-\wd0\relax
            \headtextcontent
        }
        \hbox {
            \box0
            \hskip\headnumberdistance
            \box2
        }
    \else
        \vtop{
            \headsetupspacing
            \noindent
            \headtextcontent
        }
    \fi
\stopsetups

\protect \endinput