This function does its best attempt to take whatever you provide it and turn it into a gtable. It is primarily meant to convert ggplot plots into gtables, but it will also take any grid object (grob), a recorded R base plot, or a function that generates an R base plot.
as_gtable(plot)
plot_to_gtable(plot)The plot or other graphics object to convert into a gtable. Here, plot can be
any object handled by as_grob().
To convert ggplot plots, the function needs to use a null graphics device. This can be set
with set_null_device().