[NTG-context] stretched title text

[Hans Hagen]

M.guravage wrote:

>Hi,
>
>Something has changed in the past couple months that causes my stretched
>title code to fail with the message:
>
>  ! You can't use `\end' in internal vertical mode.
>  <recently read> \normalend
>
>I've attatched a small example. Has anyone a suggestion how I can adapt my
>code accordingly?
>  
>
in a coming release i will support a more transparent stretching 
mechanism (using a font handling) so that such hacks are no longer needed

anyhow, the problem with your 'plug-in' is that it acts on a complex 
stream of tokens, run this:

\def\CapStretchAmount
  {0.3em}

\def\CapStretch
  {\let\stretchedspaceamount\CapStretchAmount
   \stretchednormalcase}

\def\stretchedbox#1%
  {\framed
     [frame=off,
      offset=.5em,
      align=middle,
      width=broad]
     {\showargument{#1}%
      \sc\CapStretch{#1}}}

\setuphead [subject][rawtextcommand=\stretchedbox]

\starttext
    \subject{feeling stretched feeling stretched feeling stretched 
feeling stretched}
    \processfile{tufte}
    \subject{feeling stretched}
    \processfile{tufte}
\stoptext

you will see that #1 is more than text, and i'm even surprised that it 
worked in previous versions.

What you actually need is a deep hook:

\def\c!deeptextcommand  {deeptextcommand}
\def\c!deepnumbercommand{deepnumbercommand}

\def\doplaceheadtext#1#2#3#4%
  {\beginheadplacement{#1}%
   \ifemptyhead % = needed
     \setbox0=\ifvertical\vbox\else\hbox\fi to \zeropoint
       {\headnumbercontentfalse
        \resetsystemmode\v!sectionnumber
        #2}%
     \makestrutofbox0
   \else % = needed
     \setbox0=\ifvertical\vbox\else\hbox\fi % \vhbox
       {\headnumbercontentfalse
        \resetsystemmode\v!sectionnumber
        % less interfering
        \ifcase\headtimingmode\or#2\fi
        % outerside font determines distance
        \dosetfontattribute{\??ko#1}\c!style
        % but we don't want color to influence user commands
        % todo: get the if-else out of it
        \getvalue{\??ko#1\c!command}
          {} % no number
          {\dostartattributes{\??ko#1}\c!style\c!color\empty
             \dostartattributes{\??ko#1}\c!textstyle\c!textcolor\empty
               \dontconvertfont
               \ifdisplaysectionhead
                 \setupinterlinespace
               \else
                 \setupspacing
               \fi
               % \ifcase\headtimingmode#2\fi % can introduce cr
               \getvalue{\??ko#1\c!commandbefore}%
               \placeheadmargintexts{#1}% binnen #3?
               \ifdisplaysectionhead
                 \getvalue{\??ko#1\c!textcommand}% struts can be nilled 
with \setnostrut
                   {\setstrut
                    \begstrut
                    \ifcase\headtimingmode\hbox{#2}\fi
                    
\executeifdefined{\??ko#1\c!deeptextcommand}\firstofoneargument{#3}
                    \endstrut}% \hbox prevents break
                 \xdef\localheadheight    {\the\strutht}%
                 \xdef\localheaddepth     {\the\strutdp}%
                 \xdef\localheadlineheight{\the\lineheight}%
                 % == \globallet\localheaddepth\strutdepth
               \else
                 \ifcase\headtimingmode#2\fi
                 \getvalue{\??ko#1\c!textcommand}%
                    
{\executeifdefined{\??ko#1\c!deeptextcommand}\firstofoneargument{#3}}%
               \fi
               \getvalue{\??ko#1\c!commandafter}%
               \ifdisplaysectionhead\endgraf\fi
             \dostopattributes
           \dostopattributes}}%
   \fi
   \endheadplacement{#1}{#4}}

\def\doplaceheadnumbertext#1#2#3#4#5% maybe move modes outside box
  {\beginheadplacement{#1}%
   \ifemptyhead % = needed
     \setbox0=\ifvertical\vbox\else\hbox\fi to \zeropoint
       {\doiftextelse{#3}
          {\setsystemmode  \v!sectionnumber\headnumbercontenttrue }
          {\resetsystemmode\v!sectionnumber\headnumbercontentfalse}%
        #2}%
     \makestrutofbox0
   \else % = needed
     \setbox0=\ifvertical\vbox\else\hbox\fi % \vhbox
       {\doiftextelse{#3}
          {\setsystemmode  \v!sectionnumber\headnumbercontenttrue }
          {\resetsystemmode\v!sectionnumber\headnumbercontentfalse}%
        % less interfering
        \ifcase\headtimingmode\or#2\fi
        % outerside font determines distance
        \dosetfontattribute{\??ko#1}\c!style
        % but we don't want color to influence user commands
        \getvalue{\??ko#1\c!command}%
          {\dostartattributes{\??ko#1}\c!style\c!color\empty
             \dostartattributes{\??ko#1}\c!numberstyle\c!numbercolor\empty
               % \getvalue{\??ko#1\c!commandbefore}% strange, why here? 
moved 21/11/2005
               \placeheadmargintexts{#1}% binnen #3?
               \ifdisplaysectionhead
                 % can be nilled with \setnostrut
                 \getvalue{\??ko#1\c!numbercommand}%
                   {\setstrut
                    \begstrut
                    
\executeifdefined{\??ko#1\c!deepnumbercommand}\firstofoneargument{#3}%
                    \endstrut}%
               \else
                 \getvalue{\??ko#1\c!numbercommand}%
                   
{\executeifdefined{\??ko#1\c!deepnumbercommand}\firstofoneargument{#3}}%
               \fi
             \dostopattributes
           \dostopattributes}
          {\dostartattributes{\??ko#1}\c!style\c!color\empty
             \dostartattributes{\??ko#1}\c!textstyle\c!textcolor\empty
               \dontconvertfont
               \ifdisplaysectionhead
                 \setupinterlinespace
               \else
                 \setupspacing
               \fi
               % \ifcase\headtimingmode#2\fi % can introduce cr
               \getvalue{\??ko#1\c!commandbefore}% makes more sense here
               \placeheadmargintexts{#1}% binnen #3?
               \ifdisplaysectionhead
                 \getvalue{\??ko#1\c!textcommand}% struts can be nilled 
with \setnostrut
                   {\setstrut
                    \begstrut
                    \ifcase\headtimingmode\hbox{#2}\fi
                    
\executeifdefined{\??ko#1\c!deeptextcommand}\firstofoneargument{#4}%
                    \endstrut}% \hbox prevents break
                 \xdef\localheadheight    {\the\strutht}%
                 \xdef\localheaddepth     {\the\strutdp}%
                 \xdef\localheadlineheight{\the\lineheight}%
                 % == \globallet\localheaddepth\strutdepth
               \else
                 \ifcase\headtimingmode#2\fi % inside textcommand ?
                 \getvalue{\??ko#1\c!textcommand}%
                   
{\executeifdefined{\??ko#1\c!deeptextcommand}\firstofoneargument{#4}}%
               \fi
               \getvalue{\??ko#1\c!commandafter}%
               \ifdisplaysectionhead\endgraf\fi
            \dostopattributes
          \dostopattributes}}%
   \fi
   \endheadplacement{#1}{#5}}

\protect

\def\CapStretchAmount
  {0.3em}

\def\CapStretch
  {\let\stretchedspaceamount\CapStretchAmount
   \stretchednormalcase}

\def\stretchedbox#1%
  {\framed
     [frame=off,
      offset=.5em,
      align=middle,
      width=broad]
     {%\showargument{#1}%
      \sc\CapStretch{#1}}}

\setuphead [subject][deeptextcommand=\stretchedbox]

\starttext
    \subject{feeling stretched feeling stretched feeling stretched 
feeling stretched}
    \processfile{tufte}
    \subject{feeling stretched}
    \processfile{tufte}
\stoptext