GEOS  3.10.1
RingClipper.h
1 /**********************************************************************
2  *
3  * GEOS - Geometry Engine Open Source
4  * http://geos.osgeo.org
5  *
6  * Copyright (C) 2020 Paul Ramsey <pramsey@cleverelephant.ca>
7  *
8  * This is free software; you can redistribute and/or modify it under
9  * the terms of the GNU Lesser General Public Licence as published
10  * by the Free Software Foundation.
11  * See the COPYING file for more information.
12  *
13  **********************************************************************/
14 
15 #pragma once
16 
17 #include <geos/export.h>
18 
19 #include <geos/geom/Envelope.h>
20 #include <geos/geom/CoordinateArraySequence.h>
21 #include <geos/geom/CoordinateSequence.h>
22 
23 // Forward declarations
24 namespace geos {
25 namespace geom {
26 class Coordinate;
27 class CoordinateSequence;
29 }
30 }
31 
32 using namespace geos::geom;
33 
34 namespace geos { // geos.
35 namespace operation { // geos.operation
36 namespace overlayng { // geos.operation.overlayng
37 
66 class GEOS_DLL RingClipper {
67 
68 private:
69 
70  // Constants
71  static constexpr int BOX_LEFT = 3;
72  static constexpr int BOX_TOP = 2;
73  static constexpr int BOX_RIGHT = 1;
74  static constexpr int BOX_BOTTOM = 0;
75 
76  // Members
77  const Envelope clipEnv;
78 
79  // Methods
80 
84  std::unique_ptr<CoordinateArraySequence> clipToBoxEdge(const CoordinateSequence* pts, int edgeIndex, bool closeRing) const;
85 
91  void intersection(const Coordinate& a, const Coordinate& b, int edgeIndex, Coordinate& rsltPt) const;
92  double intersectionLineY(const Coordinate& a, const Coordinate& b, double y) const;
93  double intersectionLineX(const Coordinate& a, const Coordinate& b, double x) const;
94  bool isInsideEdge(const Coordinate& p, int edgeIndex) const;
95 
96 
97 public:
98 
99  RingClipper(const Envelope* env)
100  : clipEnv(*env)
101  {};
102 
106  std::unique_ptr<CoordinateArraySequence> clip(const CoordinateSequence* cs) const;
107 
108 };
109 
110 
111 } // namespace geos.operation.overlayng
112 } // namespace geos.operation
113 } // namespace geos
114 
The default implementation of CoordinateSequence.
Definition: CoordinateArraySequence.h:37
The internal representation of a list of coordinates inside a Geometry.
Definition: CoordinateSequence.h:58
Coordinate is the lightweight class used to store coordinates.
Definition: Coordinate.h:60
An Envelope defines a rectangulare region of the 2D coordinate plane.
Definition: Envelope.h:58
Definition: RingClipper.h:66
std::unique_ptr< CoordinateArraySequence > clip(const CoordinateSequence *cs) const
Definition: Angle.h:27
Basic namespace for all GEOS functionalities.
Definition: Angle.h:26