diff -r 8f9905c4e1c1 -r fd82adfbe905 gui/gdc-broken_edge.cc
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gui/gdc-broken_edge.cc	Mon Nov 21 12:07:05 2005 +0000
@@ -0,0 +1,214 @@
+#include "graph_displayer_canvas.h"
+#include <cmath>
+
+GraphDisplayerCanvas::BrokenEdge::BrokenEdge(Gnome::Canvas::Group & g, Gnome::Canvas::Points p, GraphDisplayerCanvas & gc) : Line(g), gdc(gc), 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, &GraphDisplayerCanvas::BrokenEdge::edgeFormerEventHandler));
+  arrow->lower_to_bottom();
+  setPoints(p);
+}
+
+GraphDisplayerCanvas::BrokenEdge::~BrokenEdge()
+{
+  if(arrow)delete(arrow);
+}
+
+void GraphDisplayerCanvas::BrokenEdge::setPoints(Gnome::Canvas::Points p, bool move)
+{
+  bool set_arrow=false;
+  //red arrow losts its position-right button
+  if(!move)
+    {
+      if(p.size()==2)
+	{
+	  set_arrow=true;
+	  Gnome::Canvas::Points points_with_center;
+	  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];
+	    }
+	}
+    }
+  else
+    {
+      //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)
+      	{
+	  //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];
+
+	  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)
+    {
+      //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 GraphDisplayerCanvas::BrokenEdge::edgeFormerEventHandler(GdkEvent* e)
+{
+  switch(e->type)
+    {
+    case GDK_BUTTON_PRESS:
+      //we mark the location of the event to be able to calculate parameters of dragging
+      if(gdc.getActualTool()!=CREATE_NODE)
+	{
+	  gdc.toggleEdgeActivity(this, true);
+	  clicked_x=e->button.x;
+	  clicked_y=e->button.y;
+	  isbutton=true;
+	}
+      break;
+    case GDK_BUTTON_RELEASE:
+      if(gdc.getActualTool()!=CREATE_NODE)
+	{
+	  gdc.toggleEdgeActivity(this, false);
+	  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]);
+
+	  setPoints(points_new);
+	  gdc.textReposition(xy<double>(my_points[1].get_x(),my_points[1].get_y()));
+
+	  clicked_x=e->motion.x;
+	  clicked_y=e->motion.y;
+
+	}
+    default: break;
+    }
+
+  return true;
+}
+
+xy<double> GraphDisplayerCanvas::BrokenEdge::getArrowPos()
+{
+  xy<double> ret_val(my_points[1].get_x(),my_points[1].get_y());
+  return ret_val;
+}