rgb                package:grDevices                R Documentation

RGB Color Specification

Description:

     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'.

Usage:

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

Arguments:

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'.

Examples:

     rgb(0,1,0)
     (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="."))
     reds

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

