# HG changeset patch
# User hegyi
# Date 1132763099 0
# Node ID 56eb90299693297a1fe02c175d7746635ebc4ef2
# Parent  ee2bd58fdc30b87a0fe2ad8507fb845c31d4439e
No segmentation fault caused by zero long edges.

diff -r ee2bd58fdc30 -r 56eb90299693 gdc-broken_edge.cc
--- a/gdc-broken_edge.cc	Tue Nov 22 14:35:33 2005 +0000
+++ b/gdc-broken_edge.cc	Wed Nov 23 16:24:59 2005 +0000
@@ -73,38 +73,49 @@
 	  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());
+	  if((absa!=0)&&(absb!=0))
+	    {
+	      //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);
+	      //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);
+	      //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);
+	      //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);
+	      //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);
+	      //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);
+	      //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[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++)
+	      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);
+	    }
+	  else
 	    {
-	      points.push_back(my_points[i]);
+	      //if distance is 0, segmentation would be occured
+	      //in calculations, because of division by zero
+	      //But we have luck: the edge cannot be seen in
+	      //this case, so no update needed
+	      set_arrow=false;
 	    }
-	  property_points().set_value(points);
 	}
     }
   if(set_arrow)
@@ -115,8 +126,10 @@
       xy<gdouble> center( my_points[1].get_x(), my_points[1].get_y() );
 
       xy<gdouble> unit_vector_in_dir(target-center);
+      double length=sqrt( unit_vector_in_dir.normSquare() );
+
       //       std::cout << target << " - " << center << " = " << unit_vector_in_dir << "    / " <<unit_vector_in_dir.normSquare() ;
-      unit_vector_in_dir/=sqrt( unit_vector_in_dir.normSquare() );
+      unit_vector_in_dir/=length;
       //       std::cout << " = " << unit_vector_in_dir << std::endl;
 
       xy<gdouble> unit_norm_vector(0-unit_vector_in_dir.y, unit_vector_in_dir.x);
@@ -140,7 +153,7 @@
       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;
+      //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  ) );