Index: gui/broken_edge.cc
===================================================================
--- gui/broken_edge.cc	(revision 1645)
+++ gui/broken_edge.cc	(revision 1714)
@@ -47,192 +47,64 @@
       //arrow keeps its position-left button
 
+//       if(p.size()==2)
+//       	{
+//       	  Gnome::Canvas::Points points;
+//       	  my_points[0]=p[0];
+//       	  my_points[2]=p[1];
+//       	  for(int i=0;i<3;i++)
+//       	    {
+//       	      points.push_back(my_points[i]);
+//       	    }
+//       	  property_points().set_value(points);
+//       	}
+      set_arrow=true;
+
+      //////////////////////////////////////////////////////////////////////////////////////////////////////
+      /////////// keeps shape-with scalar multiplication - version 2.
+      //////////////////////////////////////////////////////////////////////////////////////////////////////
+
       if(p.size()==2)
       	{
-      	  Gnome::Canvas::Points points;
+	  //old vector from one to the other node - a
+	  xy<double> a_v(my_points[2].get_x()-my_points[0].get_x(),my_points[2].get_y()-my_points[0].get_y());
+	  //new vector from one to the other node - b
+	  xy<double> b_v(p[1].get_x()-p[0].get_x(),p[1].get_y()-p[0].get_y());
+
+	  double absa=sqrt(a_v.normSquare());
+	  double absb=sqrt(b_v.normSquare());
+
+	  //old vector from one node to the breakpoint - c
+	  xy<double> c_v(my_points[1].get_x()-my_points[0].get_x(),my_points[1].get_y()-my_points[0].get_y());
+
+	  //unit vector with the same direction to a_v
+	  xy<double> a_v_u(a_v.x/absa,a_v.y/absa);
+
+	  //normal vector of unit vector with the same direction to a_v
+	  xy<double> a_v_u_n(((-1)*a_v_u.y),a_v_u.x);
+
+	  //unit vector with the same direction to b_v
+	  xy<double> b_v_u(b_v.x/absb,b_v.y/absb);
+
+	  //normal vector of unit vector with the same direction to b_v
+	  xy<double> b_v_u_n(((-1)*b_v_u.y),b_v_u.x);
+
+	  //vector c in a_v_u and a_v_u_n co-ordinate system
+	  xy<double> c_a(c_v*a_v_u,c_v*a_v_u_n);
+
+	  //new vector from one node to the breakpoint - d - we have to calculate this one
+	  xy<double> d_v=absb/absa*(c_a.x*b_v_u+c_a.y*b_v_u_n);
+
+	  my_points[1]=Gnome::Art::Point(d_v.x+p[0].get_x(),d_v.y+p[0].get_y());
+
       	  my_points[0]=p[0];
       	  my_points[2]=p[1];
-      	  for(int i=0;i<3;i++)
-      	    {
-      	      points.push_back(my_points[i]);
-      	    }
-      	  property_points().set_value(points);
-      	}
-      set_arrow=true;
-
-      //////////////////////////////////////////////////////////////////////////////////////////////////////
-      /////////// kepps shape-with angles
-      //////////////////////////////////////////////////////////////////////////////////////////////////////
-
-
-//       //old vector from one to the other node
-//       xy<double> o_p2p(my_points[2].get_x()-my_points[0].get_x(),my_points[2].get_y()-my_points[0].get_y());
-//       //projection of the old vector to positive x axis
-//       xy<double> o_x_p2p(fabs(o_p2p.x),0);
-//       //length of p2p vector
-//       double o_l_p2p=sqrt( o_p2p.normSquare() );
-//       if(o_p2p.x<0)
-// 	{
-// 	  o_l_p2p*=-1;
-// 	}
-//       //length of projection of p2p vector
-//       double o_l_x_p2p=sqrt( o_x_p2p.normSquare() );
-//       //old angle of p2p vector to the x axis
-//       double o_a_p2p=acos(o_l_x_p2p/o_l_p2p);
-//       if(o_p2p.y>0)
-// 	{
-// 	  o_a_p2p=2*M_PI-o_a_p2p;
-// 	}
-
-//       //old vector from first node to the breakpoint
-//       xy<double> o_1b((my_points[1].get_x()-my_points[0].get_x()),(my_points[1].get_y()-my_points[0].get_y()));
-//       //projection of the old node-breakpoint vector to positive x axis
-//       xy<double> o_x_1b(fabs(o_1b.x),0);
-//       //length of 1b vector
-//       double o_l_1b=sqrt( o_1b.normSquare() );
-//       if(o_1b.x<0)
-// 	{
-// 	  o_l_1b*=-1;
-// 	}
-//       //length of projection of 1b vector
-//       double o_l_x_1b=sqrt( o_x_1b.normSquare() );
-//       //old angle of 1b vector to the x axis
-//       double o_a_1b=acos(o_l_x_1b/o_l_1b);
-//       if(o_1b.y>0)
-// 	{
-// 	  o_a_1b=2*M_PI-o_a_1b;
-// 	}
-
-//       if(p.size()==2)
-//       	{
-// 	  set_arrow=true;
-
-//       	  my_points[0]=p[0];
-//       	  my_points[2]=p[1];
-
-// 	  //new vector from one to the other node
-// 	  xy<double> n_p2p(my_points[2].get_x()-my_points[0].get_x(),my_points[2].get_y()-my_points[0].get_y());
-// 	  //projection of the new vector to positive x axis
-// 	  xy<double> n_x_p2p(fabs(n_p2p.x),0);
-// 	  //length of p2p vector
-// 	  double n_l_p2p=sqrt( n_p2p.normSquare() );
-// 	  if(n_p2p.x<0)
-// 	    {
-// 	      n_l_p2p*=-1;
-// 	    }
-// 	  //length of projection of p2p vector
-// 	  double n_l_x_p2p=sqrt( n_x_p2p.normSquare() );
-// 	  //new angle of p2p vector to the x axis
-// 	  double n_a_p2p=acos(n_l_x_p2p/n_l_p2p);
-// 	  if(n_p2p.y>0)
-// 	    {
-// 	      n_a_p2p=2*M_PI-n_a_p2p;
-// 	    }
-
-// 	  //new angle of 1b vector to the x axis
-// 	  double n_a_1b=o_a_1b+n_a_p2p-o_a_p2p;
-
-// 	  std::cout << " p2p regi: " << o_a_p2p/M_PI*180 << " uj: " << n_a_p2p/M_PI*180-(int)n_a_p2p/M_PI*180 << std::endl;
-// 	  std::cout << " 1b regi: " << o_a_1b/M_PI*180 << " uj: " << n_a_1b/M_PI*180-(int)n_a_1b/M_PI*180 << std::endl;
-
-// // 	  std::cout << o_p2p << " " << n_p2p << std::endl;
-
-// 	  if((n_a_1b>M_PI*3/2)||(n_a_1b<M_PI/2))
-// 	    {
-// 	      std::cout << "jobb terfel" << std::endl;
-// 	      my_points[1]=Gnome::Art::Point(p[0].get_x()+cos(n_a_1b)*o_l_1b*n_l_p2p/o_l_p2p,p[0].get_y()-sin(n_a_1b)*o_l_1b*n_l_p2p/o_l_p2p);
-// 	    }
-// 	  else if((n_a_1b<M_PI*3/2)&&(n_a_1b>M_PI/2))
-// 	    {
-// 	      std::cout << "bal terfel" << std::endl;
-// 	      my_points[1]=Gnome::Art::Point(p[0].get_x()-cos(n_a_1b)*o_l_1b*n_l_p2p/o_l_p2p,p[0].get_y()+sin(n_a_1b)*o_l_1b*n_l_p2p/o_l_p2p);
-// 	    }
-// 	  else
-// 	    {
-// 	      std::cout << "y tengely" << std::endl;
-// 	      double new_y=my_points[1].get_y();
-// 	      my_points[1]=Gnome::Art::Point(p[0].get_x()-cos(n_a_1b)*o_l_1b*n_l_p2p/o_l_p2p,new_y);
-// 	    }
-
-// 	  std::cout << "alap: " << p[0] << " eredeti hossz: " << o_l_1b << " nagy uj: " << n_l_p2p << " nagy regi: " << o_l_p2p << " a*b/c " << o_l_1b*n_l_p2p/o_l_p2p << " eredmeny: " << my_points[1] << std::endl;
-
-
-// // 	  if(o_1b.x*o_1b.y>0)
-// // 	    {
-// // 	      if(n_p2p.x>0)
-// // 		{
-// // 		  my_points[1]=Gnome::Art::Point(p[0].get_x()+cos(n_a_1b)*o_l_1b*n_l_p2p/o_l_p2p,p[0].get_y()+sin(n_a_1b)*o_l_1b*n_l_p2p/o_l_p2p);
-// // 		}
-// // 	      else
-// // 		{
-// // 		  my_points[1]=Gnome::Art::Point(p[0].get_x()-cos(n_a_1b)*o_l_1b*n_l_p2p/o_l_p2p,p[0].get_y()-sin(n_a_1b)*o_l_1b*n_l_p2p/o_l_p2p);
-// // 		}
-// // 	    }
-// // 	  else if(o_1b.x*o_1b.y<0)
-// // 	    {
-// // 	      if(n_p2p.x>0)
-// // 		{
-// // 		  my_points[1]=Gnome::Art::Point(p[0].get_x()+cos(n_a_1b)*o_l_1b*n_l_p2p/o_l_p2p,p[0].get_y()-sin(n_a_1b)*o_l_1b*n_l_p2p/o_l_p2p);
-// // 		}
-// // 	      else
-// // 		{
-// // 		  my_points[1]=Gnome::Art::Point(p[0].get_x()-cos(n_a_1b)*o_l_1b*n_l_p2p/o_l_p2p,p[0].get_y()+sin(n_a_1b)*o_l_1b*n_l_p2p/o_l_p2p);
-// // 		}
-// // 	    }
-// // 	  else
-// // 	    {
-// // 	    }
-
-      //////////////////////////////////////////////////////////////////////////////////////////////////////
-      /////////// kepps shape-with scalar multiplication
-      //////////////////////////////////////////////////////////////////////////////////////////////////////
-
-//       if(p.size()==2)
-//       	{
-// 	  //old vector from one to the other node - a
-// 	  xy<double> a_v(my_points[2].get_x()-my_points[0].get_x(),my_points[2].get_y()-my_points[0].get_y());
-// 	  //new vector from one to the other node - b
-// 	  xy<double> b_v(p[1].get_x()-p[0].get_x(),p[1].get_y()-p[0].get_y());
-
-// 	  //old vector from one node to the breakpoint - c
-// 	  xy<double> c_v(my_points[1].get_x()-my_points[0].get_x(),my_points[1].get_y()-my_points[0].get_y());
-
-// 	  //new vector from one node to the breakpoint - d - we have to calculate this one
-// 	  xy<double> d_v;
-
-// 	  //scalar product of a and b (old and new vector from first point to the other)
-// 	  double sab=a_v*b_v;
-// 	  //scalar product of c and d (old and new vector from first point to breakpoint)
-// 	  double scd=sab*c_v.normSquare()/a_v.normSquare();
-
-// 	  std::cout<<" a " << a_v<<" b " <<b_v<<" c " <<c_v<<" sab " <<sab<<" scd "<<scd<<std::endl;
-
-// 	  double a=c_v.normSquare();
-// 	  double b=2*scd*c_v.y;
-// 	  double c=scd*scd-b_v.normSquare()/a_v.normSquare()*c_v.normSquare()*c_v.x*c_v.x;
-
-// 	  std::cout<<" a " << a<<" b " <<b<<" c " <<c<<std::endl;
-
-// 	  d_v.y=(-b-sqrt(b*b-4*a*c))/2/a;
-
-// 	  if(c_v.x!=0)
-// 	    {
-// 	      d_v.x=(scd-c_v.y*d_v.y)/c_v.x;
-// 	    }
-// 	  else
-// 	    {
-// 	      d_v.x=my_points[1].get_x();
-// 	    }
-
-// 	  std::cout<<" d " << d_v<<std::endl;
-
-// 	  my_points[1]=Gnome::Art::Point(d_v.x+p[0].get_x(),d_v.y+p[0].get_y());
-
-// 	  Gnome::Canvas::Points points;
-// 	  for(int i=0;i<3;i++)
-// 	    {
-// 	      points.push_back(my_points[i]);
-// 	    }
-// 	  property_points().set_value(points);
-// 	}
+
+	  Gnome::Canvas::Points points;
+	  for(int i=0;i<3;i++)
+	    {
+	      points.push_back(my_points[i]);
+	    }
+	  property_points().set_value(points);
+	}
     }
   if(set_arrow)
