Updates to Boolean_operations_2 Qt4 demo (drawing actual beziers)

Boolean_set_operations_2/demo/Boolean_set_operations_2_GraphicsView/boolean_operations_2.cpp

@@ -738,7 +738,7 @@ Bezier_curve read_bezier_curve ( std::istream& is, bool aDoubleFormat )
   is >> n;
   
   // Read the control points.
-  std::vector<Bezier_rat_point>   ctrl_pts (n);
+  std::vector<Bezier_rat_point> ctrl_pts;
   
   for ( unsigned int k = 0; k < n; k++)
   {
@@ -754,12 +754,10 @@ Bezier_curve read_bezier_curve ( std::istream& is, bool aDoubleFormat )
       is >> p ;
     }
     
-    if ( k > 1 && ctrl_pts[k-1] == p ) 
+    if ( k == 0 || ctrl_pts[k-1] != p ) 
     {
-      error("Bezier data contains consecutive identical control points.");
+      ctrl_pts.push_back(p) ;
     }
-    
-    ctrl_pts[k] = p ;
   }
 
   return Bezier_curve(ctrl_pts.begin(),ctrl_pts.end());
@@ -816,7 +814,8 @@ bool read_bezier ( QString aFileName, Bezier_polygon_set& rSet )
             Bezier_traits::Make_x_monotone_2        make_x_monotone = traits.make_x_monotone_2_object();
         
             Bezier_curve B = read_bezier_curve(in_file, lDoubleFormat);
-            
+            if ( B.number_of_control_points() >= 2 )
+            {
               TRACE( "region " << r << " boundary " << b << " curve " << k );
                 
               make_x_monotone (B, std::back_inserter (x_objs));
@@ -830,6 +829,7 @@ bool read_bezier ( QString aFileName, Bezier_polygon_set& rSet )
                 }  
               }
             }
+          }  
             
           Bezier_polygon  pgn (xcvs.begin(), xcvs.end());
           

Boolean_set_operations_2/demo/Boolean_set_operations_2_GraphicsView/include/CGAL/Qt/GeneralPolygonSetGraphicsItem.h

@@ -24,6 +24,7 @@
 #include <list>
 
 #include <boost/optional.hpp>
+#include <boost/utility.hpp>
 
 #include <CGAL/function_objects.h>
 #include <CGAL/Bbox_2.h>
@@ -64,6 +65,25 @@ namespace Qt {
       typedef typename PS::Polygon_2            Polygon_2 ;
       typedef typename PS::Traits_2             Traits_2;
     } ;
+    
+    template<class Point>
+    struct arbitrary_point_helper
+    {
+      static std::pair<double,double> approximate( Point const& p )
+      {
+        return std::make_pair( to_double(p.x()), to_double(p.y()) ) ;
+      }
+      
+    };
+    
+    template <class R, class A, class N, class B>
+    struct arbitrary_point_helper< _Bezier_point_2<R,A,N,B> >
+    {
+      static std::pair<double,double> approximate( _Bezier_point_2<R,A,N,B> const& p )
+      {
+        return p.approximate();
+      }
+    } ;
   }
 
 template <class General_polygon_set_, class Compute_XM_curve_bbox_, class Draw_XM_curve_>
@@ -83,6 +103,7 @@ class GeneralPolygonSetGraphicsItem : public GraphicsItem
   typedef typename General_polygon_with_holes_vector::const_iterator General_pwh_const_iterator ; 
   typedef typename General_polygon_with_holes::Hole_const_iterator   General_hole_const_itertator ;
   typedef typename General_polygon::Curve_const_iterator             General_curve_const_iterator ;
+  typedef typename General_polygon::X_monotone_curve_2               General_X_monotone_curve_2 ;
 
   typedef Converter< Simple_cartesian<double> > ToQtConverter;
   
@@ -224,9 +245,56 @@ template <class G, class B, class D>
 template<class Visitor>
 void GeneralPolygonSetGraphicsItem<G,B,D>::traverse_polygon( General_polygon const& aP, Visitor& aVisitor)
 {
-  int c = 0 ;
-  for( General_curve_const_iterator cit = aP.curves_begin(); cit != aP.curves_end(); ++ cit )
+  //
+  // Hack to workaround some bezier incosistency proble where the ordering of the curves within the sequence is reversed
+  // w.r.t to the orientation of each curve in turn.
+  //
+
+  typedef std::vector<General_X_monotone_curve_2> XMC_vector ;
+  
+  typedef typename General_X_monotone_curve_2::Point_2 Point ;
+  
+  XMC_vector curves ;
+  std::copy(aP.curves_begin(),aP.curves_end(), std::back_inserter(curves) ) ;
+  
+  bool lFwd = true ;
+  
+  if ( curves.size() >= 2 )
   {
+    double s0x ;
+    double s0y ;
+    double t0x ;
+    double t0y ;
+    double s1x ;
+    double s1y ;
+    double t1x ;
+    double t1y ;
+    
+    boost::tie(s0x,s0y) = CGALi::arbitrary_point_helper<Point>::approximate(curves[0].source());
+    boost::tie(t0x,t0y) = CGALi::arbitrary_point_helper<Point>::approximate(curves[0].target());
+    boost::tie(s1x,s1y) = CGALi::arbitrary_point_helper<Point>::approximate(curves[1].source());
+    boost::tie(t1x,t1y) = CGALi::arbitrary_point_helper<Point>::approximate(curves[1].target());
+    
+    // squared distance between c0.target <-> c1.source
+    double dts = ((s1x-t0x)*(s1x-t0x))+((s1y-t0y)*(s1y-t0y));
+    
+    // squared distance between c1.source <-> c0.target
+    double dst = ((s0x-t1x)*(s0x-t1x))+((s0y-t1y)*(s0y-t1y));
+   
+    // The curves are reversed if c1 is followed by c0
+    if ( dst < dts )
+      lFwd = false ;
+  }
+  
+  int c = 0 ;
+  if ( lFwd )
+  {
+    for( typename XMC_vector::const_iterator cit = curves.begin(); cit != curves.end(); ++ cit )
+      aVisitor(*cit,c++);
+  }
+  else
+  {
+    for( typename XMC_vector::const_reverse_iterator cit = curves.rbegin(); cit != curves.rend(); ++ cit )
       aVisitor(*cit,c++);
   }
 }

Boolean_set_operations_2/demo/Boolean_set_operations_2_GraphicsView/typedefs.h

@@ -141,11 +141,11 @@ struct Bezier_helper
   }
 
   template<class OutputIterator>
-  static void get_control_points ( Bezier_curve const& aCurve, OutputIterator aOut )
+  static void get_control_points ( Bezier_curve const& aCurve, bool aFwd, OutputIterator aOut )
   {
     int nc = aCurve.number_of_control_points() ;
     
-    for ( int i = 0 ; i < nc ; ++ i )
+    for ( int i = aFwd ? 0 : nc - 1 ; aFwd ? i < nc : i >= 0 ; aFwd ? ++ i : -- i )
     {
       *aOut++ = Linear_point( CGAL::to_double( aCurve.control_point(i).x() )
                             , CGAL::to_double( aCurve.control_point(i).y() )
@@ -154,12 +154,14 @@ struct Bezier_helper
   }  
   
   template<class OutputIterator>
-  static void clip ( Bezier_curve const& aCurve, double aS, double aT, OutputIterator aOut )
+  static void clip ( Bezier_curve const& aCurve, double aS, double aT, bool aFwd, OutputIterator aOut )
   {
     std::vector<Linear_point> lQ ;
     
-    get_control_points(aCurve, std::back_inserter(lQ) ) ;
+    get_control_points(aCurve, aFwd, std::back_inserter(lQ) ) ;
     
+    if ( aS >= 0.0 || aT <= 1.0 )
+    {
       int nc = aCurve.number_of_control_points() ;
       int ncc = nc - 1 ;
       
@@ -174,8 +176,10 @@ struct Bezier_helper
         for ( int j = nc - i ; j <= ncc ; ++ j )
           lQ[j] = lQ[j-1] + lBeta * ( lQ[j] - lQ[j-1] ) ;
       }
+    }
     
     std::copy(lQ.begin(), lQ.end(), aOut );    
+    
   }
   
   template<class OutputIterator>
@@ -186,12 +190,12 @@ struct Bezier_helper
     double lS = get_approximated_endpoint_parameter(aBXMC.source(), lBC, aBXMC.xid());
     double lT = get_approximated_endpoint_parameter(aBXMC.target(), lBC, aBXMC.xid());
     
-    bool lFwd = aBXMC.is_vertical() || lS <= lT ;
+    bool lFwd = lS <= lT ;
     
     double lMin = lFwd ? lS : 1.0 - lS ;
     double lMax = lFwd ? lT : 1.0 - lT ;
     
-    clip(lBC, lMin, lMax, aOut ); 
+    clip(lBC, lMin, lMax, lFwd, aOut ); 
   }
 } ;
 
@@ -199,9 +203,11 @@ struct Compute_bezier_X_monotone_cuve_bbox
 {
   CGAL::Bbox_2 operator()( Bezier_X_monotone_curve const& aCurve ) const 
   {
+    return aCurve.supporting_curve().bbox();
+    
     std::vector<Linear_point> lQ ;
     
-    Bezier_helper::get_control_points(aCurve.supporting_curve(), std::back_inserter(lQ) ) ;
+    Bezier_helper::get_control_points(aCurve.supporting_curve(), true, std::back_inserter(lQ) ) ;
     
     return CGAL::bbox_2(lQ.begin(),lQ.end());
   }