\name{radialtext}
\alias{radialtext}
\title{Display text in a radial line}
\description{
 Displays a string in a radial line, rotating it to flow in the radial
 direction and optionally scaling each letter's size according to its
 distance from the center.
}
\usage{
 radialtext(x, center=c(0,0), start=NA, middle=1, end=NA, angle=0,
  deg=NA, expand=0, stretch=1, nice=TRUE, cex=NA, ...)
}
\arguments{
 \item{x}{A character string.}
 \item{center}{The center of the circular area in x/y user units.}
 \item{start}{The starting distance of the string from the center in
  x/y user units.}
 \item{middle}{The middle distance of the string from the center in
  x/y user units.}
 \item{end}{The ending distance of the string from the center in
  x/y user units.}
 \item{angle}{The angular position of the string in radians.}
 \item{deg}{The angular position of the string in degrees
  (takes precedence if not NA).}
 \item{expand}{Size expansion factor for characters, used only if
  \samp{start} specified.}
 \item{stretch}{How much to stretch the string for appearance, 1 for none.}
 \item{nice}{TRUE to auto-flip text to keep it upright, FALSE to let
  it be upside down.}
 \item{cex}{The overall character expansion factor, NA for par("cex").}
 \item{...}{Additional arguments passed to \samp{text}.}
}
\value{nil}
\details{
 This may not work on all devices, as not all graphic devices can rotate text to
 arbitrary angles. The output looks best on a Postscript or similar device that can
 rotate text without distortion. Rotated text often looks very ragged on small bitmaps.
 If the user passes a value for \samp{start}, this will override a value for
 \samp{middle} or \samp{end}. Likewise, a value for \samp{end} will override a
 value for \samp{middle}. Also, a value for \samp{deg} overrides any value passed
 to \samp{angle}. If \samp{expand} is 0, all characters will be the same size,
 while a value of 1 will scale characters so that one that is twice
 as far from the center will be twice as large. Negative values are permitted too,
 but \samp{expand} is only used if \samp{start} was specified.
}
\author{Ted Toal}
\seealso{\link{text}, \link{arctext}}
\examples{
 plot(0, xlim=c(1,5), ylim=c(1,5), main="Test of radialtext",
  xlab="", ylab="", type="n")
 points(3, 3, pch=20)
 radialtext("uncooked spaghetti", center=c(3,3),
  col="blue")
 radialtext("uncooked spaghetti", center=c(3,3),
  start=1.2, angle=pi/4, cex=0.8)
 radialtext("uncooked spaghetti", center=c(3,3),
  middle=1.2, angle=pi/4+0.1, cex=0.8)
 radialtext("uncooked spaghetti", center=c(3,3),
  end=1.2, angle=pi/4+0.2, cex=0.8)
 radialtext("uncooked spaghetti", center=c(3,3),
  start=0.5, deg=135, cex=0.8, col="green")
 radialtext("uncooked spaghetti", center=c(3,3),
  start=0.5, deg=145, cex=0.8, stretch=2)
 radialtext("uncooked spaghetti", center=c(3,3),
  start=0.5, deg=20, expand=0, col="red")
 radialtext("uncooked spaghetti", center=c(3,3),
  start=0.5, deg=250, expand=0.35)
 radialtext("uncooked spaghetti", center=c(3,3),
  start=0.75, deg=225, expand=1, col="gold")
 radialtext("uncooked spaghetti", center=c(3,3),
  start=0.5, deg=325, expand=-0.25, cex=2)
}
\keyword{misc}