R, Latex, Sweave, ggplot2 - change ggplot dimensions

Question

Cuurently I am working on a R Sweave report. And I am having some difficulties with the ggplot dimensions in the sweave pdf output. My code:

\documentclass{report}

\begin{document}

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\begin{figure}[h]
 \begin{center}
<<echo=FALSE, fig=TRUE>>=
require(ggplot2)
df <- data.frame(a= c(1:10), b = c (10:1))

ggplot(data = df, aes(a, b)) + geom_line()
@
  \caption{caption}
 \end{center}
\end{figure}

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\end{document}

Now I want to control the plot width and height dimensions in the pdf output. actually I want to keep the height the same but make the width as the same as the text width.

Thanks for your time.

Answer 1

You could try using the knitr package. (Full Disclosure: I am a minor contributor to the codebase of this package), which allows you to specify out.width, which controls the width of the figure. So, you could rewrite your code chunk as

<<echo=FALSE, out.width = '0.9\\textwidth'>>=
suppressMessages(require(ggplot2))
df <- data.frame(a= c(1:10), b = c (10:1))
ggplot(data = df, aes(a, b)) + geom_line()
@