Build a color-palette scale call for the theme block
Usage
palette_scale_call(value, aesthetic)
Arguments
- value
Palette selector: "auto" (no scale, returns NULL), "ggplot2"
(reset to the default discrete scale), or a viridis option with a type
suffix such as "viridis_d" / "magma_c".
- aesthetic
Either "fill" or "colour".
Value
A language object (the scale call), or NULL when value is "auto".