Partial colour ramp (datatype)

A representation of a partial ramp between two colours: the origin colour (from) and the distance from the origin colour to the target colour (amount, a value between 0 and 1). The target colour of the ramp can be filled in later using ramp_colours(), producing a colour.

Usage

partial_colour_ramp(amount = double(), from = "white")

Arguments

amount: Numeric vector between 0 and 1 giving amounts to ramp the colour. 0 corresponds to the colour from.
from: Character vector giving colours to ramp from.

Value

A vctrs::rcrd of class "ggdist_partial_colour_ramp" with fields "amount" and "from".

Details

This datatype is used by scale_colour_ramp to create ramped colours in ggdist geoms. It is a vctrs::rcrd datatype with two fields: "amount", the amount to ramp, and "from", the colour to ramp from.

Colour ramps can be applied (i.e. translated into colours) using ramp_colours(), which can be used with partial_colour_ramp() to implement geoms that make use of colour_ramp or fill_ramp scales.

Author

Matthew Kay

Examples

pcr = partial_colour_ramp(c(0, 0.25, 0.75, 1), "red")
pcr
#> <partial_colour_ramp[4]>
#> [1] [0 from red]    [0.25 from red] [0.75 from red] [1 from red]   

ramp_colours("blue", pcr)
#> [1] "#FF0000" "#E80050" "#9A00C3" "#0000FF"