color.gradient {plotrix} | R Documentation |
color.gradient
calculates sequences of colors by linearly
interpolating between the values specified for each color. If the length
of a vector of colors is the same as nslices
it is not changed.
If any length is greater than nslices
, it is truncated to that
length. If any color values are less than 0 or greater than 1, they
are rescaled to that range.
color.gradient(reds,greens,blues,nslices=50)
reds,greens,blues |
vectors of the values of the color components as 0 to 1. |
nslices |
The number of color "slices". |
A vector of hexadecimal color values as used by col
.
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.
Jim Lemon
# try it with red endpoints, green midpoints, and a blue vector longer # than 'nslices' color.gradient(c(0,1),c(1,0.6,0.4,0.3,0),seq(0.1,0.6,length=60))