Each Geom has an associated function that draws the key when the geom needs to be displayed in a legend. These are the options built into ggplot2.
draw_key_point(data, params, size)draw_key_abline(data, params, size)
draw_key_rect(data, params, size)
draw_key_polygon(data, params, size)
draw_key_blank(data, params, size)
draw_key_boxplot(data, params, size)
draw_key_crossbar(data, params, size)
draw_key_path(data, params, size)
draw_key_vpath(data, params, size)
draw_key_dotplot(data, params, size)
draw_key_pointrange(data, params, size)
draw_key_smooth(data, params, size)
draw_key_text(data, params, size)
draw_key_label(data, params, size)
draw_key_vline(data, params, size)
A single row data frame containing the scaled aesthetics to display in this key
A list of additional parameters supplied to the geom.
Width and height of key in mm.
A grid grob.