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110 lines
2.5 KiB
C
110 lines
2.5 KiB
C
1 month ago
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/**********************************************************************
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*
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* GEOS - Geometry Engine Open Source
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* http://geos.osgeo.org
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*
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* Copyright (C) 2005-2006 Refractions Research Inc.
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* Copyright (C) 2001-2002 Vivid Solutions Inc.
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*
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* This is free software; you can redistribute and/or modify it under
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* the terms of the GNU Lesser General Public Licence as published
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* by the Free Software Foundation.
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* See the COPYING file for more information.
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*
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**********************************************************************
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*
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* Last port: geom/Quadrant.java rev. 1.8 (JTS-1.10)
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*
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**********************************************************************/
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#ifndef GEOS_GEOM_QUADRANT_H
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#define GEOS_GEOM_QUADRANT_H
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#include <geos/export.h>
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#include <string>
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#include <geos/inline.h>
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// Forward declarations
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namespace geos {
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namespace geom {
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class Coordinate;
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}
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}
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namespace geos {
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namespace geom { // geos.geom
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/** \brief
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* Utility functions for working with quadrants.
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*
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* The quadrants are numbered as follows:
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* <pre>
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* 1 | 0
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* --+--
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* 2 | 3
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* </pre>
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*
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*/
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class GEOS_DLL Quadrant {
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public:
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static const int NE = 0;
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static const int NW = 1;
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static const int SW = 2;
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static const int SE = 3;
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/**
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* Returns the quadrant of a directed line segment
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* (specified as x and y displacements, which cannot both be 0).
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*
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* @throws IllegalArgumentException if the displacements are both 0
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*/
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static int quadrant(double dx, double dy);
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/**
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* Returns the quadrant of a directed line segment from p0 to p1.
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*
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* @throws IllegalArgumentException if the points are equal
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*/
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static int quadrant(const geom::Coordinate& p0,
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const geom::Coordinate& p1);
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/**
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* Returns true if the quadrants are 1 and 3, or 2 and 4
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*/
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static bool isOpposite(int quad1, int quad2);
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/*
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* Returns the right-hand quadrant of the halfplane defined by
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* the two quadrants,
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* or -1 if the quadrants are opposite, or the quadrant if they
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* are identical.
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*/
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static int commonHalfPlane(int quad1, int quad2);
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/**
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* Returns whether the given quadrant lies within the given halfplane
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* (specified by its right-hand quadrant).
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*/
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static bool isInHalfPlane(int quad, int halfPlane);
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/**
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* Returns true if the given quadrant is 0 or 1.
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*/
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static bool isNorthern(int quad);
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};
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} // namespace geos.geom
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} // namespace geos
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#ifdef GEOS_INLINE
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# include "geos/geom/Quadrant.inl"
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#endif
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#endif // ifndef GEOS_GEOM_QUADRANT_H
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