DrawEllipse: Draw an Ellipse

In DescTools: Tools for Descriptive Statistics

Draw an Ellipse

Description

Draw one or several ellipses on an existing plot.

Usage

DrawEllipse(x = 0, y = x, radius.x = 1, radius.y = 0.5, rot = 0,
            nv = 100, border = par("fg"), col = par("bg"),
            lty = par("lty"), lwd = par("lwd"), plot = TRUE)

Arguments

x, y	the x and y co-ordinates for the centre(s) of the ellipse(s).
radius.x	a scalar or a vector giving the semi-major axis of the ellipse.
radius.y	a scalar or a vector giving the semi-minor axis of the ellipse.
rot	angle of rotation in radians.
nv	number of vertices to draw the ellipses.
border	color for borders. The default is par("fg"). Use border = NA to omit borders.
col	color(s) to fill or shade the annulus sector with. The default NA (or also NULL) means do not fill (say draw transparent).
lty	line type for borders and shading; defaults to "solid".
lwd	line width for borders and shading.
plot	logical. If TRUE the structure will be plotted. If FALSE only the points are calculated and returned. Use this if you want to combine several geometric structures to a single polygon.

Details

Use DegToRad if you want to define rotation angle in degrees.

Value

The function invisibly returns a list of the calculated coordinates for all shapes.

Author(s)

Andri Signorell <[e-mail]>

See Also

polygon, DrawRegPolygon, DrawCircle, DrawArc

Examples

par(mfrow=c(1,2))

Canvas()
DrawEllipse(rot = c(1:3) * pi/3, col=SetAlpha(c("blue","red","green"), 0.5) )


plot(cars)
m <- var(cars)
eig <- eigen(m)
eig.val <- sqrt(eig$values)
eig.vec <- eig$vectors

DrawEllipse(x=mean(cars$speed), y=mean(cars$dist), radius.x=eig.val[1] , radius.y=eig.val[2]
  , rot=acos(eig.vec[1,1]), border="blue", lwd=3)

DescTools documentation built on Sept. 26, 2024, 1:07 a.m.