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\title{Color Palettes}
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\title{Color Palettes}
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\description{
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\description{
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  Create a vector of \code{n} contiguous colors.
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  Create a vector of \code{n} contiguous colors.
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}
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}
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\usage{
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\usage{
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rainbow(n, s = 1, v = 1, start = 0, end = max(1,n - 1)/n, alpha = 1)
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rainbow(n, s = 1, v = 1, start = 0, end = max(1, n - 1)/n, alpha = 1)
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heat.colors(n, alpha = 1)
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heat.colors(n, alpha = 1)
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terrain.colors(n, alpha = 1)
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terrain.colors(n, alpha = 1)
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topo.colors(n, alpha = 1)
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topo.colors(n, alpha = 1)
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cm.colors(n, alpha = 1)
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cm.colors(n, alpha = 1)
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}
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}
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\arguments{
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\arguments{
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  \item{n}{the number of colors (\eqn{\ge 1}) to be in the
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  \item{n}{the number of colors (\eqn{\ge 1}) to be in the
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    palette.}
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    palette.}
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  \item{s,v}{the \sQuote{saturation} and \sQuote{value} to be used
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  \item{s, v}{the \sQuote{saturation} and \sQuote{value} to be used
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    to complete the HSV color descriptions.}
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    to complete the HSV color descriptions.}
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  \item{start}{the (corrected) hue in [0,1] at which the rainbow
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  \item{start}{the (corrected) hue in [0,1] at which the rainbow
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    begins.}
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    begins.}
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  \item{end}{the (corrected) hue in [0,1] at which the rainbow ends.}
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  \item{end}{the (corrected) hue in [0,1] at which the rainbow ends.}
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  \item{alpha}{the alpha transparency, a number in [0,1], see argument
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  \item{alpha}{the alpha transparency, a number in [0,1], see argument
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    \code{alpha} in \code{\link{hsv}}.}
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    \code{alpha} in \code{\link{hsv}}.}
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}
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}
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\details{
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\details{
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  Conceptually, all of these functions actually use (parts of) a line
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  Conceptually, all of these functions actually use (parts of) a line
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  cut out of the 3-dimensional color space, parametrized by
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  cut out of the 3-dimensional color space, parametrized by
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  \code{\link{hsv}(h,s,v)}, and hence,
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  \code{\link{hsv}(h, s, v)}, and hence
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  equispaced hues in RGB space tend to cluster at
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  equispaced hues in RGB space tend to cluster at
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  the red, green and blue primaries.
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  the red, green and blue primaries.
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  Some applications such as contouring require a palette
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  Some applications such as contouring require a palette
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  of colors which do not wrap around to give a final
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  of colors which do not wrap around to give a final
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  \code{\link{col2rgb}} for translating to RGB numbers.
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  \code{\link{col2rgb}} for translating to RGB numbers.
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}
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}
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\examples{
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\examples{
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require(graphics)
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require(graphics)
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# A Color Wheel
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# A Color Wheel
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pie(rep(1,12), col=rainbow(12))
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pie(rep(1, 12), col = rainbow(12))
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##------ Some palettes ------------
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##------ Some palettes ------------
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demo.pal <-
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demo.pal <-
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  function(n, border = if (n < 32) "light gray" else NA,
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  function(n, border = if (n < 32) "light gray" else NA,
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           main = paste("color palettes;  n=",n),
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           main = paste("color palettes;  n=", n),
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           ch.col = c("rainbow(n, start=.7, end=.1)", "heat.colors(n)",
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           ch.col = c("rainbow(n, start=.7, end=.1)", "heat.colors(n)",
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                      "terrain.colors(n)", "topo.colors(n)",
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                      "terrain.colors(n)", "topo.colors(n)",
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                      "cm.colors(n)"))
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                      "cm.colors(n)"))
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{
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{
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    nt <- length(ch.col)
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    nt <- length(ch.col)