#include <Segment_2_Segment_2_intersection.h>

Collaboration diagram for Segment_2_Segment_2_pair< R >:

Public Types
enum	Intersection_results { NO, POINT, SEGMENT }

Public Member Functions
	Segment_2_Segment_2_pair ()

	Segment_2_Segment_2_pair (Segment_2< R > const seg1, Segment_2< R > const seg2)

	~Segment_2_Segment_2_pair ()

Intersection_results	intersection_type () const

bool	intersection (Point_2< R > &result) const

bool	intersection (Segment_2< R > &result) const

Protected Attributes
Segment_2< R > const *	_seg1

Segment_2< R > const *	_seg2

bool	_known

Intersection_results	_result

Point_2< R >	_intersection_point

Point_2< R >	_other_point

Detailed Description

template<class R>
class Segment_2_Segment_2_pair< R >

Definition at line 61 of file Segment_2_Segment_2_intersection.h.

Member Enumeration Documentation

enum Intersection_results

Enumerator
NO
POINT
SEGMENT

Definition at line 63 of file Segment_2_Segment_2_intersection.h.

63 {NO, POINT, SEGMENT};

Segment_2_Segment_2_pair::SEGMENT

Definition: Segment_2_Segment_2_intersection.h:63

Segment_2_Segment_2_pair::POINT

Definition: Segment_2_Segment_2_intersection.h:63

Segment_2_Segment_2_pair::NO

Definition: Segment_2_Segment_2_intersection.h:63

Constructor & Destructor Documentation

CGAL_BEGIN_NAMESPACE Segment_2_Segment_2_pair ( )

Definition at line 437 of file Segment_2_Segment_2_intersection.h.

 {
     _seg1 = 0;
     _seg2 = 0;
     _known = false;
 }

Segment_2_Segment_2_pair	(	Segment_2< R > const *	seg1,
		Segment_2< R > const *	seg2
	)

Definition at line 445 of file Segment_2_Segment_2_intersection.h.

 {
     _seg1 = seg1;
     _seg2 = seg2;
     _known = false;
 }

~Segment_2_Segment_2_pair ( )

inline

Definition at line 67 of file Segment_2_Segment_2_intersection.h.

67 {}

Member Function Documentation

bool intersection ( Point_2< R > & result ) const

Definition at line 570 of file Segment_2_Segment_2_intersection.h.

 {
     if (!_known)
         intersection_type();
     if (_result != POINT)
         return false;
     result = _intersection_point;
     return true;
 }

bool intersection ( Segment_2< R > & result ) const

Definition at line 582 of file Segment_2_Segment_2_intersection.h.

 {
     if (!_known)
         intersection_type();
     if (_result != SEGMENT)
         return false;
     result = Segment_2<R>(_intersection_point, _other_point);
     return true;
 }

Segment_2_Segment_2_pair< R >::Intersection_results intersection_type ( ) const

Definition at line 456 of file Segment_2_Segment_2_intersection.h.

References NTS::abs(), CGAL_NTS, do_overlap(), Line_2_Line_2_pair< R >::intersection(), Line_2_Line_2_pair< R >::intersection_type(), Point_2< T >::x(), Vector_2< Type >::x(), Point_2< T >::y(), and Vector_2< Type >::y().

 {
     if (_known)
         return _result;
     // The non const this pointer is used to cast away const.
     _known = true;
     if (!do_overlap(_seg1->bbox(), _seg2->bbox())) {
         _result = NO;
         return _result;
     }
     Line_2<R> const &l1 = _seg1->supporting_line();
     Line_2<R> const &l2 = _seg2->supporting_line();
     Line_2_Line_2_pair<R> linepair(&l1, &l2);
     switch ( linepair.intersection_type()) {
     case Line_2_Line_2_pair<R>::NO:
         _result = NO;
         break;
     case Line_2_Line_2_pair<R>::POINT:
         linepair.intersection(_intersection_point);
         _result = (_seg1->collinear_has_on(_intersection_point)
             && _seg2->collinear_has_on(_intersection_point)) ? POINT : NO;
         break;
     case Line_2_Line_2_pair<R>::LINE:
         {
         typedef typename R::RT RT;
         Point_2<R> const &start1 = _seg1->start();
         Point_2<R> const &end1   = _seg1->end();
         Point_2<R> const &start2 = _seg2->start();
         Point_2<R> const &end2   = _seg2->end();
         Vector_2<R> diff1 = end1-start1;
         Point_2<R> const *minpt;
         Point_2<R> const *maxpt;
         if (CGAL_NTS abs(diff1.x()) > CGAL_NTS abs(diff1.y())) {
             if (start1.x() < end1.x()) {
                 minpt = &start1;
                 maxpt = &end1;
             } else {
                 minpt = &end1;
                 maxpt = &start1;
             }
             if (start2.x() < end2.x()) {
                 if (start2.x() > minpt->x()) {
                     minpt = &start2;
                 }
                 if (end2.x() < maxpt->x()) {
                     maxpt = &end2;
                 }
             } else {
                 if (end2.x() > minpt->x()) {
                     minpt = &end2;
                 }
                 if (start2.x() < maxpt->x()) {
                     maxpt = &start2;
                 }
             }
             if (maxpt->x() < minpt->x()) {
                 _result = NO;
                 return _result;
             }
             if (maxpt->x() == minpt->x()) {
                 _intersection_point = *minpt;
                 _result = POINT;
                 return _result;
             }
             _intersection_point = *minpt;
             _other_point = *maxpt;
             _result = SEGMENT;
             return _result; 
         } else {
             if (start1.y() < end1.y()) {
                 minpt = &start1;
                 maxpt = &end1;
             } else {
                 minpt = &end1;
                 maxpt = &start1;
             }
             if (start2.y() < end2.y()) {
                 if (start2.y() > minpt->y()) {
                     minpt = &start2;
                 }
                 if (end2.y() < maxpt->y()) {
                     maxpt = &end2;
                 }
             } else {
                 if (end2.y() > minpt->y()) {
                     minpt = &end2;
                 }
                 if (start2.y() < maxpt->y()) {
                     maxpt = &start2;
                 }
             }
             if (maxpt->y() < minpt->y()) {
                 _result = NO;
                 return _result;
             }
             if (maxpt->y() == minpt->y()) {
                 _intersection_point = *minpt;
                 _result = POINT;
                 return _result;
             }
             _intersection_point = *minpt;
             _other_point = *maxpt;
             _result = SEGMENT;
             return _result; 
         }
         } 
     }
     return _result;
 }