Each geom has an associated function that draws the key when the geom needs
to be displayed in a legend. These functions are called draw_key_*(), where
* stands for the name of the respective key glyph. The key glyphs can be
customized for individual geoms by providing a geom with the key_glyph
argument (see layer() or examples below.)
draw_key_polygon_pattern(data, params, size, aspect_ratio = 1)draw_key_boxplot_pattern(data, params, size, aspect_ratio = 1)
draw_key_crossbar_pattern(data, params, size, aspect_ratio = 1)
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.
the geom's best guess at what the aspect ratio might be.
A grid grob.