R documentation on ggplot_gtable and ggplot_build [closed]

Question

I seem to be coming across the ggplot_gtable(ggplot_build(graph)) commands a lot these days when I research how to modify my ggplot graph in a particular way.

For example how to add a data table to a graph or how to overlay two graphs or How to add a line to a graph outside the plot area

I'd like to learn more and I understand that the commands are part of the base ggplot2 package but I can't find anything in the docs or my searches on them. Does anyone know where I can find more information on these commands and the tree structure of the list they create?

Thanks

Answer 1

Perhaps these links will help you out:

ggplot2 documentation

ggplot_gtable documentation

And a few ggplot examples