R: Rotate a Geometric Structure

Rotate {DescTools} | R Documentation

## Rotate a Geometric Structure

### Description

Rotate a geometric structure by an angle theta around a centerpoint xy.

### Usage

    Rotate(x, y = NULL, mx = NULL, my = NULL, theta = pi/3, asp = 1)

### Arguments

`x, y` | vectors containing the coordinates of the vertices of the polygon , which has to be rotated. The coordinates can be passed in a plotting structure (a list with x and y components), a two-column matrix, .... See `xy.coords`.
`mx, my` | xy-coordinates of the center of the rotation. If left to NULL, the centroid of the structure will be used.
`theta` | angle of the rotation
`asp` | the aspect ratio for the rotation. Helpful for rotate structures along an ellipse.

### Value

The function invisibly returns a list of the coordinates for the rotated shape(s).

### Author(s)

Andri Signorell <andri@signorell.net>

### See Also

`polygon`, `DrawRegPolygon`, `DrawEllipse`, `DrawArc`

### Examples

    # let's have a triangle
    Canvas(main="Rotation")
    x <- DrawRegPolygon(nv=3)[[1]]

    # and rotate
    sapply( (0:3) * pi/6, function(theta) {
      xy <- Rotate( x=x, theta=theta )
      polygon(xy, col=SetAlpha("blue", 0.2))
    } )

    abline(v=0, h=0)

[Package DescTools version 0.99.32 Index]