\HeaderA{rgb}{RGB Color Specification}{rgb}
\keyword{color}{rgb}
\begin{Description}\relax
This function creates \dQuote{colors} corresponding to the given
intensities (between 0 and \code{max}) of the red, green and blue
primaries.

An alpha transparency value can also be specified
(0 means fully transparent and \code{max} means opaque).
If \code{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
\code{col=} specification in graphics functions or in \code{\LinkA{par}{par}}.
\end{Description}
\begin{Usage}
\begin{verbatim}
rgb(red, green, blue, alpha, names = NULL, maxColorValue = 1)
\end{verbatim}
\end{Usage}
\begin{Arguments}
\begin{ldescription}
\item[\code{red, blue, green, alpha}] vectors of same length
with values in \eqn{[0, M]}{}
where \eqn{M}{} is \code{maxColorValue}. When this is \code{255}, the
\code{red}, \code{blue}, \code{green}, and \code{alpha}
values are coerced to
integers in \code{0:255} and the result is computed most efficiently.
\item[\code{names}] character. The names for the resulting vector.
\item[\code{maxColorValue}] number giving the maximum of the color values
range, see above.
\end{ldescription}
\end{Arguments}
\begin{SeeAlso}\relax
\code{\LinkA{col2rgb}{col2rgb}} the \dQuote{inverse} for translating \R{} colors
to RGB vectors;
\code{\LinkA{rainbow}{rainbow}}, \code{\LinkA{hsv}{hsv}}, \code{\LinkA{gray}{gray}}.
\end{SeeAlso}
\begin{Examples}
\begin{ExampleCode}
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
\end{ExampleCode}
\end{Examples}

