Centre of rotation.
Either a vector of length 2, or a character string
(partially matched to "centroid", "midpoint"
or "bottomleft").
The default is the coordinate origin c(0,0).
Value
Another object of class "im" representing the
rotated pixel image.
Details
The image is rotated by the angle specified.
Angles are measured in radians, anticlockwise.
The default is to rotate the image 90 degrees anticlockwise.