Index: broken_edge.cc
===================================================================
--- broken_edge.cc	(revision 17)
+++ broken_edge.cc	(revision 19)
@@ -1,14 +1,131 @@
 #include <broken_edge.h>
+#include <lemon/xy.h>
+#include <math.h>
 
-BrokenEdge::BrokenEdge(Gnome::Canvas::Group & g, Gnome::Canvas::Points p) : Line(g)
+BrokenEdge::BrokenEdge(Gnome::Canvas::Group & g, Gnome::Canvas::Points p) : Line(g), isbutton(false)
 {
+  my_points=new Gnome::Art::Point[3];
+
+  arrow=new Gnome::Canvas::Polygon(g);
+  *arrow << Gnome::Canvas::Properties::fill_color("red");
+  arrow->signal_event().connect(sigc::mem_fun(*this, &BrokenEdge::edge_former_event_handler));
+  set_points(p);
+}
+
+BrokenEdge::~BrokenEdge()
+{
+  if(arrow)delete(arrow);
+}
+
+void BrokenEdge::set_points(Gnome::Canvas::Points p)
+{
+  bool set_arrow=false;
   if(p.size()==2)
     {
+      set_arrow=true;
       Gnome::Canvas::Points points_with_center;
-      points_with_center.push_back(p[0]);
-      points_with_center.push_back(Gnome::Art::Point( (p[0].get_x()+p[1].get_x())/2+30 , (p[0].get_y()+p[1].get_y())/2 )+30 );
-      points_with_center.push_back(p[1]);
-      
+      points_with_center.push_back(my_points[0]=p[0]);
+      points_with_center.push_back(my_points[1]=Gnome::Art::Point( (p[0].get_x()+p[1].get_x())/2+0 , (p[0].get_y()+p[1].get_y())/2 )+0 );
+      points_with_center.push_back(my_points[2]=p[1]);
       property_points().set_value(points_with_center);
+    }  
+  if(p.size()==3)
+    {
+      set_arrow=true;
+      property_points().set_value(p);
+      for(int i=0;i<3;i++)
+	{
+	  my_points[i]=p[i];
+	}
+    }
+
+  if(set_arrow)
+    {
+      //calculating coordinates of the direction indicator arrow
+
+      xy<gdouble> target( my_points[2].get_x(), my_points[2].get_y() );
+      xy<gdouble> center( my_points[1].get_x(), my_points[1].get_y() );
+
+      xy<gdouble> unit_vector_in_dir(target-center);
+      //       std::cout << target << " - " << center << " = " << unit_vector_in_dir << "    / " <<unit_vector_in_dir.normSquare() ;
+      unit_vector_in_dir/=sqrt( unit_vector_in_dir.normSquare() );
+      //       std::cout << " = " << unit_vector_in_dir << std::endl;
+
+      xy<gdouble> unit_norm_vector(0-unit_vector_in_dir.y, unit_vector_in_dir.x);
+      //       std::cout << unit_norm_vector << std::endl;
+
+      {      
+	//       /\             top
+	//      /  \
+	//      -  -      c(enter)l(eft), ccl, ccr, cr
+	//       ||
+	//       ||       b(ottom)l, br
+      }
+
+      double size=3;
+
+      xy<gdouble> bl (center - unit_vector_in_dir * 3 * size + unit_norm_vector * size );
+      xy<gdouble> br (center - unit_vector_in_dir * 3 * size - unit_norm_vector * size );
+      xy<gdouble> ccl(center + unit_vector_in_dir *  size + unit_norm_vector * size );
+      xy<gdouble> ccr(center + unit_vector_in_dir *  size - unit_norm_vector * size );
+      xy<gdouble> cl (center + unit_vector_in_dir *  size + unit_norm_vector * 2 * size );
+      xy<gdouble> cr (center + unit_vector_in_dir *  size - unit_norm_vector * 2 * size );
+      xy<gdouble> top(center + unit_vector_in_dir * 3 * size);
+	 
+      //       std::cout << bl << " " << br << " " << ccl << " "  << ccr << " " << cl << " " << cr << " " << top << std::endl;
+
+      Gnome::Canvas::Points arrow_points;
+      arrow_points.push_back(Gnome::Art::Point( bl.x , bl.y  ) );
+      arrow_points.push_back(Gnome::Art::Point( br.x , br.y  ) );
+      arrow_points.push_back(Gnome::Art::Point( ccr.x, ccr.y ) );
+      arrow_points.push_back(Gnome::Art::Point( cr.x , cr.y  ) );
+      arrow_points.push_back(Gnome::Art::Point( top.x, top.y ) );
+      arrow_points.push_back(Gnome::Art::Point( cl.x , cl.y  ) );
+      arrow_points.push_back(Gnome::Art::Point( ccl.x, ccl.y ) );
+
+      arrow->property_points().set_value(arrow_points);
     }
 }
+
+bool BrokenEdge::edge_former_event_handler(GdkEvent* e)
+{
+  switch(e->type)
+    {
+    case GDK_BUTTON_PRESS:
+      //we mark the location of the event to be able to calculate parameters of dragging
+      clicked_x=e->button.x;
+      clicked_y=e->button.y;
+      isbutton=true;
+      break;
+    case GDK_BUTTON_RELEASE:
+      isbutton=false;
+      break;
+    case GDK_MOTION_NOTIFY:
+      //we only have to do sg. if the mouse button is pressed
+      if(isbutton)
+	{
+	  //new coordinates will be the old values,
+	  //because the item will be moved to the
+	  //new coordinate therefore the new movement
+	  //has to be calculated from here
+
+	  double dx=e->motion.x-clicked_x;
+	  double dy=e->motion.y-clicked_y;
+
+	  Gnome::Canvas::Points points_new;
+
+	  points_new.push_back(my_points[0]);
+	  points_new.push_back(my_points[1]=Gnome::Art::Point(my_points[1].get_x()+dx,my_points[1].get_y()+dy));
+	  points_new.push_back(my_points[2]);
+
+	  set_points(points_new);
+
+	  clicked_x=e->motion.x;
+	  clicked_y=e->motion.y;
+
+	}
+    default: break;
+    }
+
+  return true;
+}
