Override of includesPoint() methods in Ellipse.

Shape.cpp

@@ -371,3 +371,18 @@ void Mesh::_reorderVertices()
   // Copy.
   vertices = newVertices;
 }
+
+bool Ellipse::includesPoint(qreal x, qreal y)
+{
+  // From: http://stackoverflow.com/questions/7946187/point-and-ellipse-rotated-position-test-algorithm
+  qreal rotation = getRotationRadians();
+  const QPointF& center = getCenter();
+  qreal xDiff = x - center.x();
+  qreal yDiff = y - center.y();
+  qreal cosRotation = cos(rotation);
+  qreal sinRotation = sin(rotation);
+  qreal horizontal = (cosRotation*xDiff + sinRotation*yDiff) / getHorizontalRadius();
+  qreal vertical   = (sinRotation*xDiff - cosRotation*yDiff) / getVerticalRadius();
+  return (horizontal*horizontal + vertical*vertical) <= 1;
+}
+

Shape.h

@@ -316,6 +316,17 @@ public:
     return getVerticalAxis().length() / 2;
   }
 
+  /** Return true if Shape includes point (x,y), false otherwise
+   *  Algorithm should work for all polygons, including non-convex
+   *  Found at http://www.cs.tufts.edu/comp/163/notes05/point_inclusion_handout.pdf
+   */
+  virtual bool includesPoint(qreal x, qreal y);
+
+  virtual bool includesPoint(const QPointF& p) {
+    return includesPoint(p.x(), p.y());
+  }
+
+  // Override the parent, checking to make sure the vertices are displaced correctly.
 
 //protected:
 //  virtual void _vertexChanged(int i, Point* p=NULL) {