annotation_icon         Annotate a plot with icons at fixed positions
draw_key_icon           Legend key glyph: an icon
element_icon            Theme element: draw labels as icons
geom_icon               Icons
geom_pictogram          Pictograms
guide_pictogram         Pictogram value guide
scale_icon_identity     Use icon values as-is
scale_icon_manual       Map discrete values to icons manually
scale_value_continuous
                        Continuous scale for the pictogram value
                        aesthetic
stat_pictogram          Pictogram grid layout
