Display text in a radial line

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

x: A character string.
center: The center of the circular area in x/y user units.
start: The starting distance of the string from the center in x/y user units.
middle: The middle distance of the string from the center in x/y user units.
end: The ending distance of the string from the center in x/y user units.
angle: The angular position of the string in radians.
deg: The angular position of the string in degrees (takes precedence if not NA).
expand: Size expansion factor for characters, used only if start specified.
stretch: How much to stretch the string for appearance, 1 for none.
nice: TRUE to auto-flip text to keep it upright, FALSE to let it be upside down.
cex: The overall character expansion factor, NA for par("cex").
...: Additional arguments passed to 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 start, this will override a value for middle or end. Likewise, a value for end will override a value for middle. Also, a value for deg overrides any value passed to angle. If 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 expand is only used if start was specified.

Author

Ted Toal

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)