The following functions apply to both ellipses and elliptical arcs. In all cases, the name elliptical-object means that the argument may be an ellipse or an elliptical arc. These generic functions comprise the ellipse protocol. All classes that are subclasses of either ellipse or elliptical-arc must implement methods for these functions.
ellipse-center-point* [Generic Function]
Summary: Returns the center point of elliptical-object as two values representing the coordinate pair.
ellipse-center-point [Generic Function]
Summary: Returns the center point of elliptical-object .
ellipse-center-point is part of the ellipse Application Programmer Interface, but not part of the ellipse protocol. CLIM will supply default methods for ellipse- center-point on the protocol classes ellipse and elliptical-arc that are implemented by calling ellipse-center-point* .
ellipse-radii [Generic Function]
Summary: Returns four values corresponding to the two radius vectors of elliptical-arc . These values may be canonicalized in some way, and so may not be the same as the values passed to the constructor function.
ellipse-start-angle [Generic Function]
Summary: Returns the start angle of elliptical-object . If elliptical-object is a full ellipse or closed path, then ellipse-start-angle will return nil ; otherwise the value will be a number greater than or equal to zero, and less than 2π.
ellipse-end-angle [Generic Function]
Summary: Returns the end angle of elliptical-object . If elliptical-object is a full ellipse or closed path, then ellipse-end-angle will return nil ; otherwise the value will be a number greater than zero, and less than or equal to 2π.
Common Lisp Interface Manager 2.0 User's Guide - 3 Mar 2015