color.gradient {plotrix}

Calculate an arbitrary sequence of colors

Description

‘⁠color.gradient⁠’ is now just a call to ‘⁠color.scale⁠’ with a vector of equally spaced integers (1:nslices). The function is kept for backward compatibility.

Usage

 color.gradient(reds,greens,blues,nslices=50)

Arguments

reds, greens, blues

vectors of the values of the color components as 0 to 1.

nslices

The number of color "slices".

Value

A vector of hexadecimal color values as used by ‘⁠col⁠’.

Note

The function is mainly useful for defining a set of colors to represent a known number of gradations. Such a set can be used to assign a grade to a small number of values (e.g. points on a scatterplot - but see ‘⁠color.scale⁠’ for large numbers) and display a color bar using ‘⁠gradient.rect⁠’ as a legend.

Author(s)

Jim Lemon

See Also

rescale,approx,color.scale

Examples

 # try it with red and blue endpoints and green midpoints.
 color.gradient(c(0,1),c(1,0.6,0.4,0.3,0),c(0.1,0.6))