Create RGB Value from Numeric RGB Intensities

DESCRIPTION:

Creates an RGB value such as "FF0000" given an RGB triplet such as {255, 0, 0} .

USAGE:

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

REQUIRED ARGUMENTS:

red
a numeric vector of red intensity values between 0 and maxColorValue. Alternatively, this can be a matrix or data frame whose first three columns contain the red, green and blue values. In that case, the green and blue arguments should not be supplied.
green
a numeric vector of green intensity values between 0 and maxColorValue.
blue
a numeric vector of blue intensity values between 0 and maxColorValue.

OPTIONAL ARGUMENTS:

alpha
alpha intensity between 0 and maxColorValue. When not specified, the fully opaque color is used, e.g. alpha of 255 on the 0 to 255 scale.
names
names for the resulting vector.
maxColorValue
maximum color value. The default is 1, so RGB intensities are between 0 and 1. The other commonly used value is 255, in which case the RGB values are rounded to the closest integer between 0 and 255.

VALUE:

Character vector of RGB values in the form "#FF0000" when the color is fully opaque, and "#FF000080" when it is semi-translucent. If names is not NULL, this will be a named vector with the specified names.

SIDE EFFECTS:

None.

SEE ALSO:

.

EXAMPLES:

# Generate a sequence of gray values
x <- seq(0, 1, length=100)
rgb(x, x, x)

# Generate the colors "lavender" {230, 230, 250}
# and "olive" {128, 128, 0} and return a named vector
rgb(red=c(230, 128), green=c(230, 128), blue=c(250, 0),
    names=c("lavender", "olive"), max=255)

# Generate a sequence of semi-transparent reds
rgb(1, 0, 0, alpha=seq(0, 1, length=20))

# Generate 10 random color values
umat <- matrix(runif(30), ncol=3)
rgb(umat)