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\name{pie3D}
\alias{pie3D}
\title{Display a 3D pie chart}
\description{
Displays a 3D pie chart with optional labels.
}
\usage{
pie3D(x,edges=100,radius=1,height=0.3,theta=pi/6,start=0,border=par("fg"),
col=NULL,labels=NULL,labelpos=NULL,labelcol=par("fg"),labelcex=1.5,
sector.order=NULL,explode=0,shade=0.8,...)
}
\arguments{
\item{x}{a numeric vector for which each value will be a sector}
\item{edges}{the number of lines forming an ellipse}
\item{radius}{the radius of the pie in user units}
\item{height}{the height of the pie in user units}
\item{theta}{The angle of viewing in radians}
\item{start}{The angle at which to start drawing sectors.}
\item{border}{The color of the sector border lines}
\item{col}{The colors of the sectors}
\item{labels}{Optional labels for each sector}
\item{labelpos}{Optional positions for the labels}
\item{labelcol}{The color of the labels}
\item{labelcex}{The character expansion factor for the labels}
\item{sector.order}{Allows the operator to specify the order in
which the sectors are drawn.}
\item{explode}{The amount to "explode" the pie in user units}
\item{shade}{If > 0 and < 1, the proportion to reduce the
brightness of the sector color to get a better 3D effect.}
\item{...}{graphical parameters passed to \samp{plot}}
}
\value{
The bisecting angle of the sectors in radians.
}
\details{
\samp{pie3D} scales the values in \samp{x} so that they total 2*pi,
dropping zeros and NAs. It then displays an empty plot, calculates
the sequence for drawing the sectors and calls \samp{draw.tilted.sector}
to draw each sector. If labels are supplied, it will call \samp{pie3D.label}
to place a label for each sector. If supplied, the number of labels, label
positions and sector colors must be at least equal to the number of values
in \samp{x}. If the labels are long, it may help to reduce the radius of
the pie as in the example below.
}
\note{
Due to the somewhat primitive method used to draw sectors, a sector that
extends beyond both pi/2 and 3*pi/2 radians in either direction may not
display properly. Setting \samp{start} to pi/2 will often fix this, but
the user may have to adjust \samp{start} and the order of sectors in extreme
cases. The argument \samp{sector.order} allows the user to specify a vector
of integers that will override the calculation of the order in which the
sectors are drawn. This is usually necessary when a very large sector that
extends past 3*pi/2 is overlapped by a smaller sector next to it.
While \samp{pie3D} can be used to display a 2D pie chart by setting
height=0 and theta=pi, the labels produced by \samp{pie3D.labels} will
not be well positioned. It is probably better to use \samp{floating.pie}
for this, or use \samp{pie.labels} for the labels.
}
\author{Jim Lemon}
\seealso{\link{pie3D.labels}, \link{draw.tilted.sector}}
\examples{
pieval<-c(2,4,6,8)
pielabels<-
c("We hate\n pies","We oppose\n pies","We don't\n care","We just love pies")
pie3D(pieval,radius=0.9,labels=pielabels,explode=0.1,main="3D PIE OPINIONS")
}
\keyword{misc}
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