Hi Hans,
I installed pstoedit :

root@debian:/home/fab# dpkg --status pstoedit
Package: pstoedit
Status: install ok installed
Priority: optional
Section: graphics
Installed-Size: 662
Maintainer: Roland Stigge <stigge@antcom.de>
Architecture: amd64
Source: pstoedit (3.62-2)
Version: 3.62-2+b3
Depends: libc6 (>= 2.2.5), libpstoedit0c2a, libstdc++6 (>= 4.1.1), ghostscript
Suggests: xfig | ivtools-bin | tgif | transfig
Description: PostScript and PDF files to editable vector graphics converter
 pstoedit converts Postscript and PDF files to various editable
 vector graphic formats including tgif, xfig, PDF graphics, gnuplot format,
 idraw, MetaPost, GNU Metafile, PIC, Kontour and flattened PostScript.
Homepage: http://www.pstoedit.net/
root@debian:/home/fab#

I compiled the file as this : "context test.tex" but it is still empty
.
Thanks,
Fabrice


\setuppagenumbering[location=]

\setupcolors
  [state=start]

\setMPtext{text}{MATH\'{E}MATIQUES}


\starttext
\startuseMPgraphic{test}
picture pic ;
pic := image(graphictext \MPstring{text}
withdrawcolor red
withpen pencircle scaled 1pt ; ) ;
\stopuseMPgraphic
\stoptext




2015-08-27 10:23 GMT+02:00 Fabrice Couvreur <fabrice1.couvreur@gmail.com>:
Hi Hans,

Do you have pstoedit installed ?

root@debian:/home/fab# apt-cache search pstoedit
libpstoedit0c2a - PostScript to editable vector graphics library (runtime files)
root@debian:/home/fab#

I compile the file test.tex  with  context test.tex
Fabrice

2015-08-27 9:39 GMT+02:00 Hans Hagen <pragma@wxs.nl>:
On 8/26/2015 7:12 PM, Fabrice Couvreur wrote:
Hi,
I try to understand how this macro by testing a simple example. Why pdf
file is empty?
This question follows my question Cover page (Metafun)
http://www.ntg.nl/pipermail/ntg-context/2015/083078.html
Thank you.

\setuppagenumbering[location=]

\setupcolors
   [state=start]

\setMPtext{text}{MATHEMATIQUES}


\starttext
\startuseMPgraphic{test}
picture pic ;
pic := image(graphictext \MPstring{text}
withdrawcolor red
withpen pencircle scaled 1pt ; ) ;
addto currentpicture also pic ;
\stopuseMPgraphic
\stoptext

Do you have pstoedit installed?

Anyway, there is a new mechanism that doesn't depend on additional programs:

% outlinetext   (text) transformations ;
% outlinetext.d (text) (draw options) transformations ;
% outlinetext.f (text) (fill options) transformations ;
% outlinetext.b (text) (draw options) (fill options) transformations ;
% outlinetext.r (text) (fill options) (draw options) transformations ;

\starttext

\startMPdefinitions
    let graphictext = new_graphictext ;
\stopMPdefinitions

\startMPpage

    draw outlinetext.b
        ("\framed[align=normal]{\input{tufte}}")
        (withcolor .5white)
        (withcolor red withpen pencircle scaled 1/10)
        xsized 10cm ;

\stopMPpage

\startMPpage

    draw outlinetext.r
        ("\framed[align=normal]{\input{tufte}}")
        (withcolor red withpen pencircle scaled 1/10)
        (withcolor .5white)
        xsized 10cm ;

\stopMPpage

\startMPpage

    draw outlinetext.d
        ("\framed[align=normal]{\input{tufte}}")
        (withcolor .5white)
        xsized 10cm ;

\stopMPpage

\startMPpage

    picture p ; p := outlinetext.p("PX") ;

    for i within p :
        draw i withcolor red withpen pencircle scaled 1/10 ;
    endfor ;

\stopMPpage

\stoptext



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