colourtools.Rd
\name{colourtools}
\alias{paletteindex}
\alias{rgb2hex}
\alias{col2hex}
\alias{paletteindex}
\alias{samecolour}
\title{
Convert and Compare Colours in Different Formats
}
\description{
These functions convert between different formats for specifying
a colour in \R, and determine whether colours are equivalent.
}
\usage{
col2hex(x)
rgb2hex(v)
paletteindex(x)
samecolour(x,y)
}
\arguments{
\item{x,y}{
Any valid specification for a colour or sequence of colours
accepted by \code{\link{col2rgb}}.
}
\item{v}{
A numeric vector of length 3, giving the RGB values (0 to 255) of
a single colour, or a 3-column matrix giving the RGB values of
several colours.
}
}
\details{
\code{col2hex} converts colours specified in any format
into their hexadecimal character codes.
\code{rgb2hex} converts RGB colour values into their hexadecimal
character codes.
\code{paletteindex} checks whether the colour or colours specified
by \code{x} are available in the default palette returned by
\code{\link{palette}()}. If so, it returns the index or indices of
the colours in the palette. If not, it returns \code{NA}.
\code{samecolour} decides whether two colours \code{x} and \code{y}
are equivalent.
}
\section{Warning}{
\code{paletteindex("green")} returns \code{NA} because
the green colour in the default palette is called \code{"green3"}.
}
\value{
For \code{col2hex} and \code{rgb2hex}, a character vector containing
hexadecimal colour codes.
For \code{paletteindex}, an integer vector, possibly containing
\code{NA} values.
For \code{samecolour}, a logical value or logical vector.
}
\author{Adrian Baddeley
\email{adrian@maths.uwa.edu.au}
\url{http://www.maths.uwa.edu.au/~adrian/}
and Rolf Turner
\email{r.turner@auckland.ac.nz}
}
\seealso{
\code{\link{col2rgb}},
\code{\link{palette}}
}
\examples{
samecolour("grey", "gray")
paletteindex("grey")
}
\keyword{color}