Re: [NTG-context] Doublesided, with header text centered.

9 Jun 2006

      On Thu, 8 Jun 2006, Aditya Mahajan wrote:
...
On Thu, 8 Jun 2006, John R. Culleton wrote:
...
Here is a common situation. I need a doublesided layout so I can
adjust the backspace. I want the header text on evens and odds
centered over the text block. To simplify the issue let's say
I want "left" on the evens and "right" on the odds. If I specify
(per the manual)
\setupheadertexts[text][left][right]
then I get both words on both pages.
If I use two extra sets of [] then I can get "left" on the left
and "right" on the right but I cannot get them centered.
I am missing something obvious I am sure. Anyone have a firm
grasp of the obvious? I don't.
If I understand you correctly, use \setupheadertexts[center]. If you
want something in the left, center and right, then do
\setupheadertexts[left][right]
\setupheadertexts[center]
I misread your mail. How about something like this

\def\setupextendedheadertexts{%
   \dosixtupleempty\dosetupextendedheadertexts}

\def\dosetupextendedheadertexts[#1][#2][#3][#4][#5][#6]{
   \setupheadertexts[] %Empty the center headers
   \setupheadertexts
     %Odd page
     [{\rlap{#1}\hfill#2\hfill\llap{#3}}][]
     %Even page
     [][{\rlap{#4}\hfill#5\hfill\llap{#6}}]}

\setupextendedheadertexts[odd-left][odd-center][odd-right][even-left][even-center][even-right]

\starttext
\dorecurse{10}{This is a test \page}
\stoptext

This does not take care of "magic" texts like pagenumber, section, 
chapter. If you want that, you can try (careful with linebreaks)

\def\setupextendedheadertexts{%
   \dosixtupleempty\dosetupextendedheadertexts}

\def\dosetupextendedheadertexts[#1][#2][#3][#4][#5][#6]{
   \setupheadertexts[] %Empty the center headers
   \setupheadertexts
     %Odd page
[{\rlap{\domagic{#1}}\hfill\domagic{#2}\hfill\llap{\domagic{#3}}}][]
     %Even page
[][{\rlap{\domagic{#4}}\hfill\domagic{#5}\hfill\llap{\domagic{#6}}}]}

\unprotect
\def\domagic#1{%
   \convertargument#1\to\ascii
   \doifsomething\ascii{%
     \doifelsemarking\ascii
       {\getmarking[\ascii][\v!first]}
       {\ConvertConstantAfter\doifelse\v!pagenumber{#1}
         \@@plaatspaginanummer
         {\ConvertConstantAfter\doifelse\v!date{#1}
           {\currentdate}
           {#1{}{}{}}}}}}
\protect

\setupextendedheadertexts[date][chapter][pagenumber][pagenumber][section][Whatever]

\starttext
\dorecurse{4}{
\chapter{Chapter \recurselevel}
   \input tufte \endgraf
   \input tufte \endgraf
   \input tufte \endgraf
   \section{Section}
   \input knuth
   \input knuth
   \input knuth
}

\stoptext

Aditya