Fabrice Couvreur
9. Juli 2016 um 12:17
Hi Wolfgang,

In the first example, so I do not need the command  \currentheadnumber  but just do :

\setuphead
   [chapter]
   [command=\HeadTitle,
    headstyle=\ss,
    numbercommand=\Headed]

ConTeXt passes the section number to the argument of the \Headed command.
But in this second example, using the command \determineheadnumber[chapter], the chapter number is always 0
You need \determineheadnumber[...] each time when the value for \currentheadnumber should change.
\setuppagenumbering[location=footer]

\startusableMPgraphic{NumberHead}
      picture r ;
      r := image ( graphictext
        \MPstring{chapter}
        scaled 4pt
        withfillcolor \MPcolor{lightgray}
        withpen pencircle scaled 1pt ; ) ;
      draw r ;
    \stopusableMPgraphic

\defineoverlay[NumberHead][\uniqueMPgraphic{NumberHead}]

\def\processMPheadnumber#1%
  {\setMPtext{chapter}{\bf#1}
   \useMPgraphic{NumberHead}}

\setuphead
   [chapter]
   [command=\HeadTitle,
    headstyle=\ss,
    numbercommand=\processMPheadnumber{\currentheadnumber}]

The following works here.

\startusableMPgraphic{NumberHead}
      picture r ;
      r := image ( graphictext
        "\bf\namedheadnumber{chapter}"
        scaled 4pt
        withfillcolor \MPcolor{lightgray}
        withpen pencircle scaled 1pt ; ) ;
      draw r ;
\stopusableMPgraphic

\def\processMPheadnumber#1%
  {\useMPgraphic{NumberHead}}

\setuphead
   [chapter]
   [command=\HeadTitle,
    headstyle=\ss,
    numbercommand=\processMPheadnumber]

Wolfgang