> Fabrice Couvreur <mailto:fabrice1.couvreur@gmail.com>
> 27. September 2016 um 22:02
> Hi Wolfgang,
> Thank you for your suggestion, but I think I was not clear enough. In 
> fact, I want to place the algorithm as the image.
You need also "location=middle" for the framedtext.

\defineframedtext
   [algorithmframe]
   [width=fit,
    location=middle,
    background=color,
    backgroundcolor=lightgray,
    framecolor=darkred,
    corner=round]

\definelines
   [algorithm]
   [space=on,
    before=\startalgorithmframe,
    after=\stopalgorithmframe]

\starttext

\startmakeup[standard]
\startalgorithm
Initialisation :
   \math{u} prend la valeur 2\,000
   \math{S} prend la valeur 2\,000
Traitement :
   Pour \math{i} allant de 2 à \math{n}
      \math{u} prend la valeur \math{u\times 1,008}
      \math{S} prend la valeur \math{S +u}
   Fin Pour
Sortie :
   Afficher \math{S}
\stopalgorithm
\stopmakeup

\stoptext

Wolfgang