CIRCLES2D Description of functions operating on circles.

   Circles are represented by their center and their radius:
   C = [xc yc r];
   One sometimes considers orientation of circle, by adding an extra
   boolean value in 4-th position, with value TRUE for direct (i.e.
   turning Counter-clockwise) circles.

   Circle arcs are represented by their center, their radius, the starting
   angle and the angle extent, both in degrees:
   CA = [xc yc r theta0 dtheta];
   
   Ellipses are represented by their center, their 2 semi-axis length, and
   their angle (in degrees) with Ox direction.
   E = [xc yc A B theta];

   See also:
   ellipses2d, createCircle, createDirectedCircle, 
   isPointInCircle, isPointOnCircle, enclosingCircle, circumCircle
   intersectLineCircle, intersectCircles, radicalAxis
   circleToPolygon, circleArcToPolyline
   drawCircle, drawCircleArc

 ------
 Author: David Legland
 e-mail: david.legland@grignon.inra.fr
 Created: 2008-10-13,    using Matlab 7.4.0.287 (R2007a)
 Copyright 2010 INRA - Cepia Software Platform.

Package: matgeom