radialtext: 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

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.

Examples

Run this code

# NOT RUN {
 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)
# }