Display a floating pie chart

Displays a pie chart at an arbitrary position on an existing plot

Usage

floating.pie(xpos=0,ypos=0,x,edges=200,radius=1,col=NULL,startpos=0,
  shadow=FALSE,shadow.col=c("#ffffff","#cccccc"),explode=0,...)

Arguments

xpos,ypos: x and y position of the center of the pie chart
x: a numeric vector for which each value will be a sector
edges: the number of lines forming a circle
radius: the radius of the pie in user units
col: the colors of the sectors - defaults to rainbow
startpos: The starting position for drawing sectors in radians.
shadow: Logical - whether to draw a shadow
shadow.col: Colors to use for a shadow.
explode: How much to "explode" one or more of the sectors.
...: graphical parameters passed to polygon

Details

floating.pie displays a pie chart with an optional shadow on an existing plot (see polygon.shadow). floating.pie now accepts NAs or zeros in x, but simply ignores them.

floating.pie can be useful when multiple pie charts are placed on a plot overlaying something else, like a map.

Value

The bisecting angle of the sectors in radians. Useful for placing text labels for each sector. If any values in x were zero or NA, no angle is returned for that value. This means that the user must adjust the labels accordingly if pie.labels is called.

If floating.pie is called with no graphics device, it will try to open one with the appropriate dimensions.

If pie.labels is called, ensure that the center of the pie chart and any explode values are the same.

Note

As with most pie charts, simplicity is essential. Trying to display a complicated breakdown of data rarely succeeds.

Author

Jim Lemon

Examples

 plot(1:5,type="n",main="Floating Pie test",xlab="",ylab="",axes=FALSE)
 box()
 polygon(c(0,0,5.5,5.5),c(0,3,3,0),border="#44aaff",col="#44aaff")
 floating.pie(1.7,3,c(2,4,4,2,8),radius=0.5,
  col=c("#ff0000","#80ff00","#00ffff","#44bbff","#8000ff"))
 floating.pie(3.1,3,c(1,4,5,2,8),radius=0.5,
  col=c("#ff0000","#80ff00","#00ffff","#44bbff","#8000ff"))
 floating.pie(4,1.5,c(3,4,6,7),radius=0.5,
  col=c("#ff0066","#00cc88","#44bbff","#8000ff"))
 draw.circle(3.9,2.1,radius=0.04,col="white")
 draw.circle(3.9,2.1,radius=0.04,col="white")
 draw.circle(3.9,2.1,radius=0.04,col="white")
 draw.circle(4,2.3,radius=0.04,col="white")
 draw.circle(4.07,2.55,radius=0.04,col="white")
 draw.circle(4.03,2.85,radius=0.04,col="white")
 text(c(1.7,3.1,4),c(3.7,3.7,3.7),c("Pass","Pass","Fail"))

 plot(0,xlim=c(-1.5,1.5),ylim=c(-1.5,1.5),type="n",axes=FALSE,
  main="Floating pie with minor explosions",xlab="",ylab="")
 floating.pie(x=1:5,explode=c(0,0.1,0,0.2,0))