\documentclass[a4paper]{article}
\usepackage[latin1]{inputenc}
\usepackage{color, pdfcolmk}
\begin{document}
\DefineVerbatimEnvironment{Sinput}{Verbatim}{formatcom = {\color[rgb]{0, 0, 0.56}}}
\SweaveOpts{prefix.string = figs/essai, eps = FALSE, pdf = TRUE}
\setkeys{Gin}{width=0.8\textwidth}
Essayons de faire un histogramme :
<<essaifig, echo = T, fig = T>>= 
hist(rnorm(1000), col = "pink")
@
\end{document}