Hi Wolfgang,
You offered me the following code to write algorithms. It seems that this
does not function very well because the withdrawal of the text no longer
exists.
Thank you
Fabrice

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

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

\starttext

\startalgorithm
Variables \math{I} et \math{J} entiers
T tableau d'entiers
Début
Pour \math{I} allant de \math{1} à \math{3}
    Pour \math{J} allant de \math{1} à \math{3}
      Si \math{J>I}
         Alors \math{T[I, J]=J-I}
         Sinon \math{T[I, J]=0}
      Fin Si
    Fin Pour
Fin
\stopalgorithm

\stoptext