A window.
An object of class owin,
or data in any format acceptable to as.owin().
Value
A list with two components x and y, which are numeric
vectors of length 4 giving the coordinates of the four corner points
of the (bounding rectangle of the) window.
Details
This trivial function is occasionally convenient.
If 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.