Returns the four corners of a rectangle
An object of class
This trivial function is occasionally convenient.
window is of type
"rectangle" this returns the
four corners of the window itself;
otherwise, it returns the corners of the bounding rectangle
of the window.
A list with two components
y, which are numeric
vectors of length 4 giving the coordinates of the four corner points
of the (bounding rectangle of the) window.
1 2 3