CGAL users discussion list

[David Keller <>]

Hi,

I have some issues with Arrangement_with_history_2:

  1. operator== in Arr_with_history_2_functions.h misses a return value
     for the case of non-self-assignments. Attached is a patch
     (arr_with_hist_return_value.patch) which fixes the problem for me.
  2. If VERBOSE is defined there are several issues with
     function-name-lookups in derived objects leading to compile-time
     errors (at least for gcc 4.0 and later). Attached is a patch
     (sweep_line_debug.patch) to fix this problem.
  3. Inserting an overlapping but "not equal" curve in an
     Arrangement_with_history_2 leads to a runtime-error (precondition
     failure in Arrangement_2_functions.h at line 1579). Attached is a
     reproducer (arr_with_history_overlapping_curves.cpp). What should
     traits::equal_2_object() implement here: Equal graph or equal
     representation? The case may actually be rare. However, I'm not
     quite sure if the current implementation gives the desired
     behavior. If so, it would possibly be a good choice to mention
     this in the documentation.

Thanks and kind regards
David Keller
diff -Naur CGAL-3.3.1/include/CGAL/Arrangement_2/Arr_with_history_2_functions.h CGAL-3.3.1patched/include/CGAL/Arrangement_2/Arr_with_history_2_functions.h
--- CGAL-3.3.1/include/CGAL/Arrangement_2/Arr_with_history_2_functions.h	2007-08-25 21:01:33.000000000 +0200
+++ CGAL-3.3.1patched/include/CGAL/Arrangement_2/Arr_with_history_2_functions.h	2008-03-06 12:48:55.000000000 +0100
@@ -74,7 +74,7 @@
     return (*this);
   
   assign (arr);
-  return;
+  return (*this);
 }
 
 //-----------------------------------------------------------------------------

diff -Naur CGAL-3.3.1/include/CGAL/Basic_sweep_line_2.h CGAL-3.3.1patched/include/CGAL/Basic_sweep_line_2.h
--- CGAL-3.3.1/include/CGAL/Basic_sweep_line_2.h	2007-08-25 21:01:32.000000000 +0200
+++ CGAL-3.3.1patched/include/CGAL/Basic_sweep_line_2.h	2008-03-14 08:25:40.000000000 +0100
@@ -47,7 +47,7 @@
 #define CGAL_PRINT_INSERT(a) { std::cout << "+++ inserting "; \
                           (a)->Print(); \
                           std::cout << "    currentPos = "; \
-                          PrintEvent(m_currentEvent); \
+                          this->PrintEvent(this->m_currentEvent); \
                           std::cout << "\n"; \
                           }
 #define CGAL_PRINT_ERASE(a)  { std::cout << "--- erasing " ; \
diff -Naur CGAL-3.3.1/include/CGAL/Sweep_line_2.h CGAL-3.3.1patched/include/CGAL/Sweep_line_2.h
--- CGAL-3.3.1/include/CGAL/Sweep_line_2.h	2007-08-25 21:01:33.000000000 +0200
+++ CGAL-3.3.1patched/include/CGAL/Sweep_line_2.h	2008-03-14 08:27:51.000000000 +0100
@@ -315,7 +315,7 @@
   void _handle_right_curves()
   {
     CGAL_PRINT("Handling right curves (" ;);
-    CGAL_SL_DEBUG(PrintEvent(m_currentEvent););
+    CGAL_SL_DEBUG(PrintEvent(this->m_currentEvent););
     CGAL_PRINT(")\n";);
     
     if(! this->m_currentEvent->has_right_curves())
@@ -340,7 +340,7 @@
                                         *currentOne);
     ((Subcurve*)(*currentOne))->set_hint(slIter);
   
-    CGAL_SL_DEBUG(PrintStatusLine(););
+    CGAL_SL_DEBUG(this->PrintStatusLine(););
     if ( slIter != this->m_statusLine.begin() )
     { 
       //  get the previous curve in the y-str
@@ -359,7 +359,7 @@
         (this->m_status_line_insert_hint, *currentOne);
       ((Subcurve*)(*currentOne))->set_hint(slIter);
         
-      CGAL_SL_DEBUG(PrintStatusLine(););
+      CGAL_SL_DEBUG(this->PrintStatusLine(););
     
       //BZBZ
       // if the two curves were neighbours before, we dont need to intersect them again
@@ -370,7 +370,7 @@
       ++currentOne;
     }        
       
-    CGAL_SL_DEBUG(PrintStatusLine(););
+    CGAL_SL_DEBUG(this->PrintStatusLine(););
 
     //the next Subcurve at the Y-str 
     ++slIter;
@@ -493,7 +493,7 @@
                               
 {
   CGAL_PRINT("remove_curve_from_status_line\n";);
-  CGAL_SL_DEBUG(PrintStatusLine(););
+  CGAL_SL_DEBUG(this->PrintStatusLine(););
   CGAL_SL_DEBUG(leftCurve->Print(););
 
   StatusLineIter sliter = leftCurve->get_hint(); 

#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
#include <CGAL/Arrangement_with_history_2.h>
#include <CGAL/Arr_polyline_traits_2.h>
#include <CGAL/Arr_non_caching_segment_traits_2.h>
#include <CGAL/Arr_extended_dcel.h>

struct VertexData
{};

struct HalfedgeData
{};

struct FaceData
{};

typedef CGAL::Exact_predicates_inexact_constructions_kernel Kernel;
typedef CGAL::Arr_non_caching_segment_traits_2<Kernel>      SegmentTraits;
typedef CGAL::Arr_polyline_traits_2<SegmentTraits>          Traits;
typedef CGAL::Arr_extended_dcel<Traits, VertexData, HalfedgeData, FaceData>
                                                            Dcel;
typedef CGAL::Arrangement_with_history_2<Traits,Dcel>       Arrangement;
typedef Traits::Curve_2                                     Curve;
typedef Traits::Point_2                                     Point;


int main()
{
  Arrangement arr;

  std::vector<Curve> curves;
  std::vector<Point> points;
  
  points.push_back( Point( 0., 1. ) );
  points.push_back( Point( 12., 1. ) );
  curves.push_back( Curve( points.begin(), points.end() ) );

  points.clear();
  points.push_back( Point( 12., 1. ) );
  points.push_back( Point( 10.0223, 8.94903 ) );
  points.push_back( Point( 10., 11. ) );
  curves.push_back( Curve( points.begin(), points.end() ) );

  points.clear();
  points.push_back( Point( 10., 11. ) );
  points.push_back( Point( 6.11947, 6.9141 ) );
  points.push_back( Point( 0., 1. ) );
  curves.push_back( Curve( points.begin(), points.end() ) );

  points.clear();
  points.push_back( Point( 10., 11. ) );
  points.push_back( Point( 6.94507, 8.18988 ) );
  points.push_back( Point( 6., 5. ) );
  curves.push_back( Curve( points.begin(), points.end() ) );

  CGAL::insert_curves( arr, curves.begin(), curves.end() );

  points.clear();
  points.push_back( Point( 0., 1. ) );
  points.push_back( Point( 7.08165, 1. ) );
  points.push_back( Point( 12., 1. ) );

  CGAL::insert_curve( arr, Curve( points.begin(), points.end() ) );


  return 0;
}