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]


But in this second example, using the command
\determineheadnumber[chapter], the
chapter number is always 0

\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}}


\unexpanded\def\HeadTitle#1#2%
  {\framed
    [frame=off,
    bottomframe=on,
    width=broad,
    align={broad,nothyphenated,left}]
    {#1\blank[nowhite]#2}}

\determineheadnumber[chapter]

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

\starttext

\startchapter
  [title={Fist chapter}]

\input knuth

\stopchapter

\startchapter
  [title={Second chapter}]

\input knuth

\stopchapter

\startchapter
  [title={Third chapter}]

\input knuth

\stopchapter

\stoptext

2016-07-09 11:32 GMT+02:00 Wolfgang Schuster <schuster.wolfgang@gmail.com>:

> Fabrice Couvreur <fabrice1.couvreur@gmail.com>
> 9. Juli 2016 um 11:12
> Hello,
> In this command, I have two problems :
>
> - \currentheadnumber does not work
>
> You need
>
>     \determineheadnumber[chapter]
>
> before you can access the value with
>
>     \currentheadnumber
>
> - the chapter number appears in black
>
> You need this setup:
>
> \setuphead
>    [chapter]
>    [numbercommand=\Headed]
>
> Wolfgang
>
>
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