97 lines
2.8 KiB
C
97 lines
2.8 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) 2023 Paul Ramsey <pramsey@cleverelephant.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/LineSegment.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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class GeometryFactory;
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class Polygon;
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}
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}
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using geos::geom::CoordinateXY;
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using geos::geom::GeometryFactory;
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using geos::geom::LineSegment;
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using geos::geom::Polygon;
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namespace geos {
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namespace algorithm {
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class GEOS_DLL Rectangle {
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public:
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/**
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* Creates a rectangular {@link Polygon} from a base segment
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* defining the position and orientation of one side of the rectangle, and
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* three points defining the locations of the line segments
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* forming the opposite, left and right sides of the rectangle.
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* The base segment and side points must be presented so that the
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* rectangle has CW orientation.
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*
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* The rectangle corners are computed as intersections of
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* lines, which generally cannot produce exact values.
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* If a rectangle corner is determined to coincide with a side point
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* the side point value is used to avoid numerical inaccuracy.
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*
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* The first side of the constructed rectangle contains the base segment.
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*
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* @param baseRightPt the right point of the base segment
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* @param baseLeftPt the left point of the base segment
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* @param oppositePt the point defining the opposite side
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* @param leftSidePt the point defining the left side
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* @param rightSidePt the point defining the right side
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* @param factory the geometry factory to use
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* @return the rectangular polygon
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*/
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static std::unique_ptr<Polygon>
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createFromSidePts(
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const CoordinateXY& baseRightPt,
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const CoordinateXY& baseLeftPt,
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const CoordinateXY& oppositePt,
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const CoordinateXY& leftSidePt,
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const CoordinateXY& rightSidePt,
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const GeometryFactory* factory);
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private:
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/**
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* Computes the constant C in the standard line equation Ax + By = C
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* from A and B and a point on the line.
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*
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* @param a the X coefficient
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* @param b the Y coefficient
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* @param p a point on the line
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* @return the constant C
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*/
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static double
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computeLineEquationC(double a, double b, const CoordinateXY& p);
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static LineSegment
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createLineForStandardEquation(double a, double b, double c);
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};
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} // namespace geos::algorithm
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} // namespace geos
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