ggplot_build() takes the plot object, and performs all steps necessary
to produce an object that can be rendered. This function outputs two pieces:
a list of data frames (one for each layer), and a panel object, which
contain all information about axis limits, breaks etc.
ggplot_build(plot)layer_data(plot, i = 1L)
layer_scales(plot, i = 1L, j = 1L)
layer_grob(plot, i = 1L)
ggplot object
An integer. In layer_data(), the data to return (in the order added to the
plot). In layer_grob(), the grob to return (in the order added to the
plot). In layer_scales(), the row of a facet to return scales for.
An integer. In layer_scales(), the column of a facet to return
scales for.
layer_data(), layer_grob(), and layer_scales() are helper
functions that return the data, grob, or scales associated with a given
layer. These are useful for tests.
print.ggplot() and benchplot() for
functions that contain the complete set of steps for generating
a ggplot2 plot.