Hi,
This macro was written by Otared and it works well unless I change the size of the font (see the second graph).
How to correct this problem ?
Thanks for your help.
Fabrice

%%%% begin example

\usemodule[pgfplots]
\pgfplotsset{compat=newest}
\define[2]\cscript{\start\switchtobodyfont[xitsbidi]\m{{\mathscript{#1}}_{#2}}\stop}

\starttext

 \startmidaligned
 \starttikzpicture
 \startaxis
   \addplot {x};
   \node[above left] at (2,2) {\cscript{C}{f}};
   \stopaxis  
 \stoptikzpicture
 \stopmidaligned
 \blank
 \startmidaligned
  \switchtobodyfont[9pt]
  \starttikzpicture
  \startaxis
   \addplot {x};
   \node[above left] at (2,2) {\cscript{C}{f}};
   \stopaxis  
 \stoptikzpicture
 \stopmidaligned
 
\stoptext

%%%%end example