CVS commit by domi: 

'forward-port' the documentation


  A            locus_imp.cc   1.1.2.1
  A            locus_imp.h   1.1.2.1
  M +9 -0      curve_imp.h   1.1.2.2


--- kdeedu/kig/objects/curve_imp.h  #1.1.2.1:1.1.2.2
@@ -22,4 +22,6 @@
 #include "object_imp.h"
 
+//  abc (abstract base class) representing a curve: something which is
+//  composed of points, like a line, a circle, a locus...
 class CurveImp
   : public ObjectImp
@@ -27,5 +29,12 @@ class CurveImp
   typedef ObjectImp Parent;
 public:
+  // param is between 0 and 1.  Note that 0 and 1 should be the
+  // end-points.  E.g. for a Line, getPoint(0) returns a more or less
+  // infinite point.  getPoint(0.5) should return the point in the
+  // middle.
   virtual double getParam( const Coordinate& point ) const = 0;
+  // this should be the inverse function of getPoint().
+  // Note that it should also do something reasonable when p is not on
+  // the curve.
   virtual const Coordinate getPoint( double param ) const = 0;
   bool inherits( int typeID ) const;