circle: Draw circles on an existing plot.

In friendly/matlib: Matrix Functions for Teaching and Learning Linear Algebra and Multivariate Statistics

Draw circles on an existing plot.

Description

Draw circles on an existing plot.

Usage

circle(
  x,
  y,
  radius,
  nv = 60,
  border = NULL,
  col = NA,
  lty = 1,
  density = NULL,
  angle = 45,
  lwd = 1
)

Arguments

x, y	Coordinates of the center of the circle. If x is a vector of length 2, y is ignored and the center is taken as x[1], x[2].
radius	Radius (or radii) of the circle(s) in user units.
nv	Number of vertices to draw the circle.
border	Color to use for drawing the circumference. polygon
col	Color to use for filling the circle.
lty	Line type for the circumference.
density	Density for patterned fill. See polygon.
angle	Angle of patterned fill. See polygon.
lwd	Line width for the circumference.

Details

Rather than depending on the aspect ratio par("asp") set globally or in the call to plot, circle uses the dimensions of the current plot and the x and y coordinates to draw a circle rather than an ellipse. Of course, if you resize the plot the aspect ratio can change.

This function was copied from draw.circle

Value

Invisibly returns a list with the x and y coordinates of the points on the circumference of the last circle displayed.

Author(s)

Jim Lemon, thanks to David Winsemius for the density and angle args

See Also

polygon

Examples

plot(1:5,seq(1,10,length=5),
     type="n",xlab="",ylab="",
     main="Test draw.circle")
# draw three concentric circles
circle(2, 4, c(1, 0.66, 0.33),border="purple",
            col=c("#ff00ff","#ff77ff","#ffccff"),lty=1,lwd=1)
# draw some others
circle(2.5, 8, 0.6,border="red",lty=3,lwd=3)
circle(4, 3, 0.7,border="green",col="yellow",lty=1,
            density=5,angle=30,lwd=10)
circle(3.5, 8, 0.8,border="blue",lty=2,lwd=2)

friendly/matlib documentation built on March 3, 2024, 12:18 p.m.