title: Specify height and width of ggplot graph in Rmarkdown knitr output
body: <p>I have created a plot with ggplot2 where the x-axis labels are not readable unless the plot is larger than default. When viewing in Rstudio I am able to resize dynamically. When saving with ggsave() I am able to specify height and width. How would I do this within the Rmarkdown file so that the output contains a plot of the desired size?</p>