104 строки
2.9 KiB
C++
104 строки
2.9 KiB
C++
/**********************************************************************
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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) 2011 Sandro Santilli <strk@kbt.io>
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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: algorithm/HCoordinate.java r386 (JTS-1.12+)
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*
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**********************************************************************/
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#ifndef GEOS_ALGORITHM_HCOORDINATE_H
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#define GEOS_ALGORITHM_HCOORDINATE_H
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#include <geos/export.h>
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#include <iosfwd>
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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 algorithm { // geos::algorithm
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/** \brief
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* Represents a homogeneous coordinate in a 2-D coordinate space.
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*
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* HCoordinate are used as a clean way
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* of computing intersections between line segments.
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*/
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class GEOS_DLL HCoordinate {
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public:
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friend std::ostream& operator<< (std::ostream& o, const HCoordinate& c);
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/** \brief
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* Computes the (approximate) intersection point between two line
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* segments using homogeneous coordinates.
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*
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* @note this algorithm is not numerically stable; i.e. it can
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* produce intersection points which lie outside the envelope of the
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* line segments themselves. In order to increase the precision of
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* the calculation input points should be normalized before
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* passing them to this routine.
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*/
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static void intersection(const geom::Coordinate& p1,
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const geom::Coordinate& p2,
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const geom::Coordinate& q1,
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const geom::Coordinate& q2,
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geom::Coordinate& ret);
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double x, y, w;
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HCoordinate();
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HCoordinate(double _x, double _y, double _w);
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HCoordinate(const geom::Coordinate& p);
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/** \brief
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* Constructs a homogeneous coordinate which is the intersection
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* of the lines define by the homogenous coordinates represented
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* by two [Coordinates](@ref geom::Coordinate).
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*
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* @param p1
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* @param p2
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*/
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HCoordinate(const geom::Coordinate& p1, const geom::Coordinate& p2);
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HCoordinate(const geom::Coordinate& p1, const geom::Coordinate& p2,
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const geom::Coordinate& q1, const geom::Coordinate& q2);
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HCoordinate(const HCoordinate& p1, const HCoordinate& p2);
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double getX() const;
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double getY() const;
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void getCoordinate(geom::Coordinate& ret) const;
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};
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std::ostream& operator<< (std::ostream& o, const HCoordinate& c);
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} // namespace geos::algorithm
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} // namespace geos
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#endif // GEOS_ALGORITHM_HCOORDINATE_H
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