include/geos/geomgraph/EdgeIntersection.h

   1 /**********************************************************************
   2  *
   3  * GEOS - Geometry Engine Open Source
   4  * http://geos.osgeo.org
   5  *
   6  * Copyright (C) 2009-2011 Sandro Santilli <strk@keybit.net>
   7  * Copyright (C) 2005-2006 Refractions Research Inc.
   8  * Copyright (C) 2001-2002 Vivid Solutions Inc.
   9  *
  10  * This is free software; you can redistribute and/or modify it under
  11  * the terms of the GNU Lesser General Public Licence as published
  12  * by the Free Software Foundation.
  13  * See the COPYING file for more information.
  14  *
  15  **********************************************************************
  16  *
  17  * Last port: geomgraph/EdgeIntersection.java rev. 1.5 (JTS-1.10)
  18  *
  19  **********************************************************************/
  20
  21
  22 #ifndef GEOS_GEOMGRAPH_EDGEINTERSECTION_H
  23 #define GEOS_GEOMGRAPH_EDGEINTERSECTION_H
  24
  25 #include <geos/export.h>
  26
  27 #include <geos/geom/Coordinate.h> // for composition and inlines
  28
  29 #include <geos/inline.h>
  30
  31 #include <ostream>
  32
  33
  34 namespace geos {
  35 namespace geomgraph { // geos.geomgraph
  36
  37 /**
  38  * Represents a point on an edge which intersects with another edge.
  39  *
  40  * The intersection may either be a single point, or a line segment
  41  * (in which case this point is the start of the line segment)
  42  * The intersection point must be precise.
  43  *
  44  */
  45 class GEOS_DLL EdgeIntersection {
  46 public:
  47
  48         // the point of intersection
  49         geom::Coordinate coord;
  50
  51         // the edge distance of this point along the containing line segment
  52         double dist;
  53
  54         // the index of the containing line segment in the parent edge
  55         int segmentIndex;
  56
  57         EdgeIntersection(const geom::Coordinate& newCoord,
  58                          int newSegmentIndex, double newDist)
  59           :
  60           coord(newCoord),
  61           dist(newDist),
  62           segmentIndex(newSegmentIndex)
  63         {}
  64
  65         bool isEndPoint(int maxSegmentIndex) const {
  66           if (segmentIndex==0 && dist==0.0) return true;
  67           if (segmentIndex==maxSegmentIndex) return true;
  68           return false;
  69         }
  70
  71         const geom::Coordinate& getCoordinate() const {
  72                 return coord;
  73         }
  74
  75         int getSegmentIndex() const { return segmentIndex; }
  76
  77         double getDistance() const { return dist; }
  78
  79 };
  80
  81 /// Strict weak ordering operator for EdgeIntersection
  82 //
  83 /// This is the C++ equivalent of JTS's compareTo
  84 inline bool operator< (const EdgeIntersection& ei1, const EdgeIntersection& ei2)
  85 {
  86                 if ( ei1.segmentIndex < ei2.segmentIndex ) return true;
  87                 if ( ei1.segmentIndex == ei2.segmentIndex )
  88     {
  89       if ( ei1.dist < ei2.dist ) return true;
  90
  91       // TODO: check if the Coordinate matches, or this will
  92       //       be a robustness issue in computin distance
  93       //       See http://trac.osgeo.org/geos/ticket/350
  94     }
  95                 return false;
  96 }
  97
  98 // @deprecated, use strict weak ordering operator
  99 struct GEOS_DLL  EdgeIntersectionLessThen {
 100         bool operator()(const EdgeIntersection *ei1,
 101                 const EdgeIntersection *ei2) const
 102         {
 103     return *ei1 < *ei2;
 104         }
 105 };
 106
 107 /// Output operator
 108 inline std::ostream& operator<< (std::ostream& os, const EdgeIntersection& e)
 109 {
 110   os << e.coord << " seg # = " << e.segmentIndex << " dist = " << e.dist;
 111         return os;
 112 }
 113
 114 } // namespace geos.geomgraph
 115 } // namespace geos
 116
 117 #endif // ifndef GEOS_GEOMGRAPH_EDGEINTERSECTION_H
 118
 119