1 files changed, 533 insertions, 333 deletions
diff --git a/tex/context/base/strc-ren.mkiv b/tex/context/base/strc-ren.mkiv
index b7b4224cd..d9cebc17f 100644
--- a/tex/context/base/strc-ren.mkiv
+++ b/tex/context/base/strc-ren.mkiv
@@ -15,7 +15,10 @@
 
 \unprotect
 
-\newconstant\headtimingmode
+\newbox\b_strc_rendering_head
+
+\newdimen\d_strc_rendering_local_leftoffset
+\newdimen\d_strc_rendering_local_rightoffset
 
 % Martin Kolarik's problem:
 %
@@ -23,90 +26,57 @@
 % \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
+\newtoks\everyheadstart
 
-\unexpanded\def\setupheadcomponentfont#1#2%
+\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
-   \ifconditional\headisdisplay
-     \edef\askedheadinterlinespace{\headparameter\c!interlinespace}%
-     \ifx\askedheadinterlinespace\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
-       \ifconditional\fontattributeisset \ifconditional\interlinespaceisset \else
-         \setupinterlinespace
-       \fi \fi
-       \setfalse\fontattributeisset \useheadstyleandcolor#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
-       \useheadstyleandcolor\c!style\c!color
-       \ifconditional\fontattributeisset
-         \dosetupcheckedinterlinespace\askedheadinterlinespace
-       \fi
-       \setfalse\fontattributeisset
-       \useheadstyleandcolor#1#2%
-       \ifconditional\fontattributeisset
-         \dosetupcheckedinterlinespace\askedheadinterlinespace
-       \fi
-     \fi
+   \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
+     \useheadstyleandcolor\c!style\c!color\relax
      \ifconditional\fontattributeisset
-       \setupspacing
+       \dosetupcheckedinterlinespace\p_strc_rendering_interlinespace
      \fi
      \setfalse\fontattributeisset
-     \useheadstyleandcolor#1#2%
+     \useheadstyleandcolor#1#2\relax
      \ifconditional\fontattributeisset
-       \setupspacing
+       \dosetupcheckedinterlinespace\p_strc_rendering_interlinespace
      \fi
    \fi}
 
-\def\doplaceheadtextcomponent#1%
-  {\begingroup
-     \setupheadcomponentfont\c!textstyle\c!textcolor
-     \headparameter\c!commandbefore
-     \ifcsname\currentheadhash\c!deeptextcommand\endcsname
-       \expandafter\let\expandafter\deepstructuretitlecommand\csname\currentheadhash\c!deeptextcommand\endcsname
-     \fi
-     \ifconditional\headisdisplay % \ifdisplaysectionhead
-       % struts can be nilled with \setnostrut
-       \headparameter\c!textcommand{\setstrut\begstrut#1\endstrut}%
-       \xdef\localheadheight    {\the\strutht}%
-       \xdef\localheaddepth     {\the\strutdp}%
-       \xdef\localheadlineheight{\the\lineheight}%
-       % == \globallet\localheaddepth\strutdepth
-     \else
-       \headparameter\c!textcommand{#1}%
-     \fi
-     \headparameter\c!commandafter
-     \ifconditional\headisdisplay % \ifdisplaysectionhead
-       \endgraf
-     \fi
-   \endgroup}
-
-\def\doplaceheadnumbercomponent#1%
-  {\begingroup
-     \setupheadcomponentfont\c!numberstyle\c!numbercolor
-     \ifcsname\currentheadhash\c!deepnumbercommand\endcsname
-       \expandafter\let\expandafter\deepstructurenumbercommand\csname\currentheadhash\c!deepnumbercommand\endcsname
-     \fi
-     \ifconditional\headisdisplay % \ifdisplaysectionhead
-       % can be nilled with \setnostrut
-       \headparameter\c!numbercommand{\setstrut\begstrut#1\endstrut}%
-     \else
-       \headparameter\c!numbercommand{#1}%
-     \fi
-   \endgroup}
-
-% \newif\ifheadnumbercontent
-% \newif\ifemptyhead
-% \newif\ifdisplaysectionhead
+\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
 
@@ -142,42 +112,45 @@
       % maybe auto: backreference when given, else list
    \fi\fi}
 
-\unexpanded\def\placecurrentheadtext
-  {\beginheadplacement
+% 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\headleaveempty
-     \setbox\sectionheadbox\hbox \headreferenceattributes to \zeropoint{}%
-     \makestrutofbox\sectionheadbox
+   \ifconditional\c_strc_sectioning_empty
+     \setbox\b_strc_rendering_head\hbox \headreferenceattributes to \zeropoint{\strut}%
    \else
      \docheckheadreference
-     \setbox\sectionheadbox\hbox \headreferenceattributes
+     \setbox\b_strc_rendering_head\hbox \headreferenceattributes
        {\spac_grids_set_local_snapping{\headparameter\c!internalgrid}%
         \doresettructureheadnumbercontent
         \useheadstyleparameter\c!style
         \setinlineheadreferenceattributes
-        \headparameter\c!command{}{\doplaceheadtextcomponent\getheadtitle}}%
+        \strc_rendering_inject_text}%
    \fi
-   \endheadplacement{\getheadsyncs}}
+   \strc_rendering_stop_placement}
 
-\unexpanded\def\placecurrentheadnumbertext
-  {\beginheadplacement
+\unexpanded\def\strc_rendering_place_head_number_and_text
+  {\strc_rendering_start_placement
    \setheadmarking
-   \doiftextelse{\getheadnumber}\dosettructureheadnumbercontent\doresettructureheadnumbercontent
-   \ifconditional\headleaveempty
-     \setbox\sectionheadbox\hbox \headreferenceattributes to \zeropoint{}%
-     \makestrutofbox\sectionheadbox
+   \doiftextelse\getheadnumber
+     \dosettructureheadnumbercontent
+     \doresettructureheadnumbercontent
+   \ifconditional\c_strc_sectioning_empty
+     \setbox\b_strc_rendering_head\hbox \headreferenceattributes to \zeropoint{\strut}%
    \else % = needed
      \docheckheadreference
-     \setbox\sectionheadbox\hbox \headreferenceattributes
+     \setbox\b_strc_rendering_head\hbox \headreferenceattributes
        {\spac_grids_set_local_snapping{\headparameter\c!internalgrid}%
         \useheadstyleparameter\c!style
         \setinlineheadreferenceattributes
-        \headparameter\c!command{\doplaceheadnumbercomponent\getheadnumber}{\doplaceheadtextcomponent\getheadtitle}}%
+        \strc_rendering_inject_number_and_text}%
    \fi
-   \endheadplacement{\getheadsyncs}}
+   \strc_rendering_stop_placement}
 
-\unexpanded\def\placecurrentheadempty
+\unexpanded\def\strc_rendering_place_head_empty
   {\hbox \headreferenceattributes {\getheadsyncs}}
 
 %D \starttyping
@@ -192,54 +165,96 @@
 %D \MySubject{feeling stretched feeling stretched feeling stretched feeling stretched}
 %D \stoptyping
 
-\let\headlastlinewidth\!!zeropoint
+% helpers
 
-\def\localheadheight    {\strutht}
-\def\localheaddepth     {\strutdp}
-\def\localheadlineheight{\lineheight}
+% \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}
 
-\def\dolocalheadsetup  %  koppeling met standaard kopcommando / engels
-  {\forgetall          %  traag dus ...
-   \doifsomething{\headparameter\c!align    }     {\normalexpanded{\noexpand\setupalign    [\headparameter\c!align    ]}}%
-   \doifsomething{\headparameter\c!tolerance}     {\normalexpanded{\noexpand\setuptolerance[\headparameter\c!tolerance]}}%
-   \doif         {\headparameter\c!strut    }\v!no{\setnostrut}% new
-   \def\\{\crlf\strut\ignorespaces}}
+\unexpanded\def\startlocalheadsetup{\bgroup\strc_rendering_initialize_spacing}
+\unexpanded\def\stoplocalheadsetup {\egroup}
 
-\def\beginheadplacement
+\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
-   \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 !
+   %
+   \strc_rendering_initialize_alternatives
+   \strc_rendering_initialize_dimensions
+   %
+   \strc_rendering_initialize_line_state
+   \reseteverypar % needed indeed
+   \noindent      % ipv \whitespace elders, na \forgetall !
    \bgroup
-   \doifinsetelse{\headparameter\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}%
+   \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
-   \iflocation
-     \ifconditional\headisdisplay % \ifdisplaysectionhead
-     \else
-       % obsolete: \noninterferingmarks
-     \fi
-   \fi
-   \resetinteractionparameter\c!style
+   \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
-   %\strictouterreferencestrue % tzt instelling
-   \let\localheadsetup\dolocalheadsetup}
+   \resetinteractionparameter\c!contrastcolor}
 
 % \setuphead[chapter]         [style=\bfd,after=,hang=line] % fit broad 2
 % \setuphead[section]         [style=\bfc,after=,hang=line]
@@ -259,87 +274,106 @@
 % \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\headisdisplay % \ifdisplaysectionhead
-     % new (todo tight == one following line up)
-     \processaction
-       [\headparameter\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
+\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\currentheadgridsnapping{\headparameter\c!grid}%
+         \edef\p_grid{\headparameter\c!grid}%
          \ifconditional\headisdisplay
-           \ifx\currentheadgridsnapping\empty\else
+           \ifx\p_grid\empty\else
              \useheadstyleandcolor\c!style\c!color
              \setupinterlinespace
              \useheadstyleandcolor\c!textstyle\c!textcolor
              \setupinterlinespace
            \fi
          \fi
-         \snaptogrid[\currentheadgridsnapping]\hbox
-           {\hskip\localheadskip\hskip\headparameter\c!margin\box\sectionheadbox}%
+         \snaptogrid[\p_grid]\hbox
+           {\hskip\dimexpr\d_strc_rendering_local_leftoffset+\headparameter\c!margin\relax\box\b_strc_rendering_head}%
        \egroup
      \else
        \hbox
-         {\hskip\localheadskip\hskip\headparameter\c!margin\box\sectionheadbox}%
+         {\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\noflines>\zerocount
-         \dorecurse\noflines{\nointerlineskip\dosomebreak\nobreak\strut\endgraf}% to be checked
+       \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
-     #1%
+     \getheadsyncs
    \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\continuousheadsignal\ignorespaces
+     \unhbox\b_strc_rendering_head
+     \getheadsyncs
+     \hskip\headnumberdistance\s!plus\headnumberdistance\s!minus.25\dimexpr\headnumberdistance\relax
+     \strc_sectioning_inject_continuous_signal
    \fi
-   \ifconditional\headisdisplay % \ifdisplaysectionhead
+   \ifconditional\headisdisplay
      \ifvmode
        \ifgridsnapping % important, font related depth, see comment
          \prevdepth\strutdp
        \else
-         \prevdepth\localheaddepth
+         \prevdepth\d_strc_rendering_local_depth
        \fi
      \fi
    \fi
    \egroup
    \egroup
-   \ifconditional\headisdisplay % \ifdisplaysectionhead
+   \ifconditional\headisdisplay
      \useindentnextparameter\headparameter
    \else
      \nonoindentation % recently added, was a bug
@@ -359,56 +393,168 @@
 %   \input tufte \par
 % \stopnarrower
 
-\installcorenamespace{headplacementalternative}
-\installcorenamespace{headplacementnature}
-
-\let\numberheadalternative\v!normal
-
-\unexpanded\def\defineheadplacement
-  {\dodoubleargument\dodefineheadplacement}
-
-% \def\dodefineheadplacement[#1][#2]% #3#4
-%   {\setvalue{\??headplacementnature#1}{#2}%
-%    \setvalue{\??headplacementalternative#1}}
-
 % \dodefineheadplacement[sectiona][vertical]{#1->#2}
 % \dodefineheadplacement[sectionb][vertical]#1#2{#1->#2}
 %
 % \setuphead[section][alternative=sectiona]
 % \setuphead[subsection][alternative=sectionb]
 
-\def\dodefineheadplacementyes[#1][#2]%#3#4%
-  {\setvalue{\??headplacementnature#1}{#2}%
-   \setvalue{\??headplacementalternative#1}##1##2}
+% \startsetups[\??headrenderings:\v!vertical:\v!sectiona]
+%     ... there will be a more public namespace
+% \stopsetups
+
+\installcorenamespace{headplacementalternative}
+\installcorenamespace{headrenderings}
+\installcorenamespace{headalternative}
 
-\def\dodefineheadplacementnop[#1][#2]%
-  {\setvalue{\??headplacementnature#1}{#2}%
-   \setvalue{\??headplacementalternative#1}}
+\installcommandhandler \??headalternative {headalternative} \??headalternative % or just \??head
 
-\def\dodefineheadplacement[#1][#2]%
+\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
-     {\dodefineheadplacementyes[#1][#2]}%
-     {\dodefineheadplacementnop[#1][#2]}}
+     {\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}
 
-\def\presetnumberheadalternative
-  {\doifelsevalue{\??headplacementnature\numberheadalternative}\v!horizontal\setfalse\settrue\headisdisplay}
+\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
 
-\def\normalplacehead
-  {\csname\??headplacementalternative\ifcsname\??headplacementalternative\numberheadalternative\endcsname\numberheadalternative\else\v!normal\fi\endcsname}
+\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}
 
-\def\setheaddisplay % used in strc-sec
-  {\doifelsevalue{\??headplacementnature\headparameter\c!alternative}\v!horizontal
-     {\setfalse\headisdisplay}
-     {\settrue \headisdisplay}}
+\startsetups[\??headrenderings:\v!command]
+    \csname\??headplacementalternative\currentheadalternative\endcsname \headnumbercontent \headtextcontent
+\stopsetups
 
-\defineheadplacement[\v!paragraph][\v!vertical]#1#2%
-  {\vbox
-     {\localheadsetup
-      \begstrut
-      \ifconditional\headshownumber % \ifheadnumbercontent
-        #1\hskip\numberheaddistance
-      \fi
-      #2}}
+% 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]
@@ -417,129 +563,183 @@
 % \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      {\headparameter\c!width      }%
-      \edef\headnumberwidth{\headparameter\c!numberwidth}%
-      \edef\headtextwidth  {\headparameter\c!textwidth  }%
-      \ifconditional\headshownumber
-        \ifx\headwidth\empty
-        \else
-          \ifx\headnumberwidth\empty
-            \ifx\headtextwidth\empty\else
-              \edef\headnumberwidth{\the\dimexpr\headwidth-\headtextwidth\relax}%
+\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
-          \else
-            \ifx\headtextwidth\empty
-              \edef\headtextwidth{\the\dimexpr\headwidth-\headnumberwidth\relax}%
+            \ifdim\headnumberwidth=\zeropoint\else
+                \headnumberdistance\zeropoint
             \fi
-          \fi
-          \hsize\headwidth
-        \fi
-        \ifx\headnumberwidth\empty\else
-          \let\numberheaddistance\!!zeropoint
+            \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
-        \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
+        \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
-        \hangindent\scratchdimen
-        \hangafter \plusone
-        \noindent
-        \box\scratchbox\hskip\numberheaddistance
-      \else
-        \ifx\headtextwidth\empty
-          \ifx\headwidth\empty
-          \else
-            \hsize\headwidth
-          \fi
-        \else
-          \hsize\headtextwidth
+        \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
-        \noindent
-      \fi
-      #2}}
-
-% \unexpanded\def\placeheadmarginalternative#1#2%
-%   {\vbox
-%      {\localheadsetup
-%       \begstrut % use one \strut here!
-%       \dontleavehmode % in case there is no strut, else side effects with llap
-%       \ifconditional\headshownumber
-%         \llap{\hbox{\hfill{#1}\hskip\localheadskip\hskip\leftmargindistance}}% introduces whitespace
-%         % maybe better:
-%         % \inleftmargin{\hbox{\hss{#1}\hskip\localheadskip}}%
-%       \fi
-%       {#2}}}
-
-\unexpanded\def\placeheadmarginalternative#1#2%
- {\vbox
-    {\localheadsetup
-     \begstrut % use one \strut here!
-     \dontleavehmode % in case there is no strut, else side effects with llap
-     \ifconditional\headshownumber
-       \llap{\hbox{\hfill{#1}\hskip\dimexpr\localheadskip+\doifoddpageelse\leftmargindistance\rightmargindistance\relax}}% introduces whitespace
-     \fi
-     {#2}}}
-
-\defineheadplacement[\v!inmargin][\v!vertical]#1#2{\placeheadmarginalternative{#1}{#2}}
-\defineheadplacement[\v!margin]  [\v!vertical]#1#2{\placeheadmarginalternative{#1}{#2}}
-
-\defineheadplacement[\v!middle][\v!vertical]#1#2%
-  {\vbox
-     {\localheadsetup
-      \veryraggedcenter
-      \let\\\endgraf
-      \let\crlf\endgraf
-      \ifconditional\headshownumber
-        \strut#1\par
-      \fi
-      \begstrut#2}}
-
-\defineheadplacement[\v!text][\v!horizontal]#1#2%
-  {\bgroup
-   \localheadsetup % no stretch in distance
-   \ifconditional\headshownumber
-     {#1}\kern\numberheaddistance
-   \fi
-   {\begstrut#2}%
-   \egroup}
-
-\unexpanded\def\placeheadlohialternative#1#2#3%
-  {\ifconditional\headshownumber
-     \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{\placeheadlohialternative\vbox{#1}{#2}}
-\defineheadplacement[\v!top]   [\v!vertical]#1#2{\placeheadlohialternative\vtop{#1}{#2}}
-
-% 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\localheadsetup}
-\unexpanded\def\stoplocalheadsetup {\egroup}
+        \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