rgb {grDevices}R Documentation

RGB Color Specification


This function creates “colors” corresponding to the given intensities (between 0 and max) of the red, green and blue primaries.

An alpha transparency value can also be specified (0 means fully transparent and max means opaque). If alpha is not specified, an opaque colour is generated.

The names argument may be used to provide names for the colors.

The values returned by these functions can be used with a col= specification in graphics functions or in par.


rgb(red, green, blue, alpha, names = NULL, maxColorValue = 1)


red, blue, green, alpha vectors of same length with values in [0, M] where M is maxColorValue. When this is 255, the red, blue, green, and alpha values are coerced to integers in 0:255 and the result is computed most efficiently.
names character. The names for the resulting vector.
maxColorValue number giving the maximum of the color values range, see above.

See Also

col2rgb the “inverse” for translating R colors to RGB vectors; rainbow, hsv, hcl, gray.


(u01 <- seq(0,1, length=11))
stopifnot(rgb(u01,u01,u01) == gray(u01))
reds <- rgb((0:15)/15, g=0,b=0, names=paste("red",0:15,sep="."))

rgb(0, 0:12, 0, max = 255)# integer input

[Package grDevices version 2.2.1 Index]