Legend keys

draw_key_halftone() draws a mid-tone swatch at the layer's screen angle and shape: dots, or strips for a line screen. The key is a sample of the screen itself, run over a key-sized area by the code that draws the panel, so it reads at the density of the fill it stands for. draw_key_spot() draws a disc at the break's tone or, for a size legend, at the break's radius. Both are the default keys of the corresponding geoms. They are exported for use with key_glyph.

Usage

draw_key_halftone(data, params, size)

draw_key_spot(data, params, size)

Arguments

data

A single row data frame containing the scaled aesthetics to display in this key

params

A list of additional parameters supplied to the geom.

size

Width and height of key in mm.

Value

A grob.