Fixed drawing of distance circles

code/Plotty.h

@@ -108,6 +108,7 @@ public:
 
 	K::GnuplotSplotElementEmpty emptyElem;
 
+    std::vector<int> distanceCircles;
 
 	K::GnuplotSplotElementPM3D pm3doutline;
 
@@ -186,7 +187,7 @@ public:
 
     }
 
-    void addCircle(int id, const Point2& center, float radius, const K::GnuplotColor& strokeColor)
+    void addDistanceCircle(const Point2& center, float radius, const K::GnuplotColor& strokeColor)
     {
         auto c = K::GnuplotCoordinate2(center.x, center.y, K::GnuplotCoordinateSystem::FIRST);
         auto r = K::GnuplotCoordinate1(radius, K::GnuplotCoordinateSystem::FIRST);
@@ -196,8 +197,19 @@ public:
 
         K::GnuplotObjectCircle* obj = new K::GnuplotObjectCircle(c, r, fill, stroke);
 
-        splot.getObjects().set(id, obj);
+        splot.getObjects().add(obj);
 
+        distanceCircles.push_back(obj->getID());
+    }
+
+    void clearDistanceCircles()
+    {
+        for (int oldID : distanceCircles)
+        {
+            splot.getObjects().remove(oldID);
+        }
+
+        distanceCircles.clear();
     }
 
 	void addBBoxes(const BBoxes3& boxes, const K::GnuplotColor& c) {