85 lines
2.6 KiB
C
85 lines
2.6 KiB
C
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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) 2019 Paul Ramsey <pramsey@cleverlephant.ca>
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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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#pragma once
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#include <geos/export.h>
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#include <geos/geom/Coordinate.h>
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#include <geos/geom/CoordinateSequence.h>
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namespace geos {
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namespace algorithm {
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/** \brief
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* Functions to compute intersection points between lines and line segments.
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*
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* In general it is not possible to compute
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* the intersection point of two lines exactly, due to numerical roundoff.
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* This is particularly true when the lines are nearly parallel.
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* These routines uses numerical conditioning on the input values
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* to ensure that the computed value is very close to the correct value.
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*
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* The Z-ordinate is ignored, and not populated.
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*/
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class GEOS_DLL Intersection {
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public:
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/** \brief
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* Computes the intersection point of two lines.
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* If the lines are parallel or collinear this case is detected
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* and <code>null</code> is returned.
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*
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* @param p1 an endpoint of line 1
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* @param p2 an endpoint of line 1
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* @param q1 an endpoint of line 2
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* @param q2 an endpoint of line 2
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* @return the intersection point between the lines, if there is one,
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* or null if the lines are parallel or collinear
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*
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* @see CGAlgorithmsDD#intersection(Coordinate, Coordinate, Coordinate, Coordinate)
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*/
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static geom::CoordinateXY intersection(const geom::CoordinateXY& p1, const geom::CoordinateXY& p2,
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const geom::CoordinateXY& q1, const geom::CoordinateXY& q2);
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/**
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* Computes the intersection point of a line and a line segment (if any).
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* There will be no intersection point if:
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*
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* * the segment does not intersect the line
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* * the line or the segment are degenerate (have zero length)
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*
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* If the segment is collinear with the line the first segment endpoint is returned.
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*
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* @param line1 a point on the line
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* @param line2 a point on the line
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* @param seg1 an endpoint of the line segment
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* @param seg2 an endpoint of the line segment
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* @return the intersection point, or null if it is not possible to find an intersection
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*/
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static geom::CoordinateXY intersectionLineSegment(
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const geom::CoordinateXY& line1,
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const geom::CoordinateXY& line2,
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const geom::CoordinateXY& seg1,
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const geom::CoordinateXY& seg2);
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};
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} // namespace geos::algorithm
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} // namespace geos
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