How to control the dimension / size of a plot with ggplot2

Question

I am using ggplot2 (respectively qplot) to generate a report with Sweave. Now I need some help with the adjustment of the size of the plot. I use the following Sweave code t

Answer 1

The Sweave options width and height influence the dimensions of the PDF file but not the size of the figures in the document. Put something like

\setkeys{Gin}{width=0.4\textwidth}

after \begin{document} to get smaller plots.

Source: Sweave manual, sec. 4.1.2