shotGroups (version 0.1)

drawCircle: Draw a single circle

Description

Adds a single circle to an already opened plot.

Usage

drawCircle(x, y, radius, nv = 100, fg = par('fg'), bg = NA,
           colCtr = NA, lty = par('lty'), lwd = par('lwd'),
           pch = par('pch'), cex = par('cex'))

Arguments

x

a numerical value giving the center's x-coordinate.

y

a numerical value giving the center's y-coordinate.

radius

a numerical vector giving the circle's radius.

nv

number of vertices in the approximating polygon.

fg

color of the circle's rim.

bg

color of the circle's fill color. Set to NA for a fully transparent circle.

colCtr

color of the center point. Set to NA to omit.

lty

line type of the circle.

lwd

line width of the circle.

pch

symbol used for the center of the circle.

cex

magnification factor for symbol used for the center of the circle.

Details

This function is mainly a wrapper for polygon. To draw more than a few circles efficiently, use symbols instead.

See Also

polygon

Examples

c1 <- c(1, 2)                 # circle center
c2 <- c(2, 3)                 # another circle center
r1 <- 2                       # circle radius
r2 <- 0.5                     # another circle radius

# determine axis limits so that circles will be visible
xLims <- c1[1] + c(-r1, r1)
yLims <- c1[2] + c(-r1, r1)

plot(c1[1], c1[2], type='n', asp=1, xlim=xLims, ylim=yLims)
drawCircle(c1[1], c1[2], r1, fg='blue', colCtr='blue', pch=19)
drawCircle(c2[1], c2[2], r2, fg='red', bg='red', colCtr='black', pch=4)