title: How to control the dimension / size of a plot with ggplot2
body: <p>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 to include it.</p>
  
  <pre><code>\begin{figure}[htbp]
  \begin{center}
  &lt;&lt;fig=true,echo=false&gt;&gt;=
  print(mygraph)
  @
  \caption{MyCaption}
  \end{center}
  \end{figure}
  </code></pre>
  
  <p>If I add a width argument (like shown below) to plot is squeezed down, but not really scaled down. </p>
  
  <pre><code>&lt;&lt;fig=true,echo=false,width=3&gt;&gt;=
  </code></pre>
  
  <p>If I use ggsave() instead, I could use a scale argument and influence the size of the resulting .pdf file. Is there a way to influence the dimensions of the plot without saving it (since the .pdf is generated by Sweave anyway) ? Is there anything I need to add to my qplot code?</p>
  
  <pre><code>mygraph=qplot(date,value,data=graph1,geom="line",colour=variable,xlab="",ylab="")
  + scale_y_continuous(limits = c(-0.3,0.3))
  </code></pre>
  
  <p>Thx for any suggestions in advance!</p>