% Fichier ex12.1.1-1.tex - Ch. Rolland/O Reilly France
\documentclass{article}
\usepackage[latin1]{inputenc}
\begin{document}
\newcommand{\bftext}[1]{%
\newlength{\bftextLarg}
\settowidth{\bftextLarg}{#1}%
#1\hspace{-\bftextLarg}%
\hspace{.3pt}#1}
Texte \bftext{en gras}
\end{document}
