An object of the class Ellipse is an ellipse in twodimensional Euclidean plane $$ _{2}. Its boundary splits the plane into a bounded and an unbounded side. By definition, an empty Ellipse has no boundary and no bounded side, i.e. its unbounded side equals the whole plane $$ _{2}.
 
Point type.


 sets ellipse to the empty ellipse. 

 sets ellipse to the ellipse containing exactly $${p$$}. 

 sets ellipse to the ellipse containing exactly the segment connecting p and q. The algorithm guarantees that set is never called with two equal points. 

 
sets ellipse to the smallest ellipse through p,q,r. The algorithm guarantees that set is never called with three collinear points.  

 
sets ellipse to the smallest ellipse through p,q,r,s. The algorithm guarantees that this ellipse exists.  

 
sets ellipse to the unique conic through p,q,r,s,t. The algorithm guarantees that this conic is an ellipse. 

 
returns true, iff p lies properly outside of ellipse. 
Each of the following predicates is only needed, if the corresponding predicate of Min_ellipse_2 is used.

 returns CGAL::ON_BOUNDED_SIDE, CGAL::ON_BOUNDARY, or CGAL::ON_UNBOUNDED_SIDE iff p lies properly inside, on the boundary, or properly outside of ellipse, resp. 

 
returns true, iff p lies properly inside ellipse.  

 
returns true, iff p lies on the boundary of ellipse.  

 returns true, iff ellipse is empty (this implies degeneracy). 

 returns true, iff ellipse is degenerate, i.e. if ellipse is empty or equal to a single point. 
The following I/O operators are only needed, if the corresponding I/O operators of Min_ellipse_2 are used.

 writes ellipse to output stream os. 

 writes ellipse to window stream ws. 