Common Lisp Interface Manager 2.0 User's Guide > Chapter 2 Drawing Graphics > 2.5 General Geometric Objects in CLIM > 2.5.6 Ellipses and Elliptical Arcs in CLIM

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 - 22 Dec 2009