Key glyphs for 'radius' legends — draw_key

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.)

Usage

draw_key_fields(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 grid grob

Details

The layer geom_fields() allows for a special aesthetic radius. This function draws a key glyph for this aesthetics, where the radius of the arrow corresponds with the scalar value listed with this radius. Note that the width of the key glyph cannot be adjusted by the aesthetic itself. Therefore, if your max_radius parameter exceeds the glyph width, you need to change the width of the guides yourself, see vignette("radius_aes") for more details.

Author

Pepijn de Vries

Examples

if (requireNamespace("ggplot2")) {
  library(ggplot2)
  p <- ggplot(economics, aes(date, psavert, color = "savings rate"))
  p + geom_line(key_glyph = "fields")
}