DYT/Tool/OpenSceneGraph-3.6.5/include/geos/noding/NodingIntersectionFinder.h

/**********************************************************************
 *
 * GEOS - Geometry Engine Open Source
 * http://geos.osgeo.org
 *
 * Copyright (C) 2006      Refractions Research Inc.
 *
 * This is free software; you can redistribute and/or modify it under
 * the terms of the GNU Lesser General Public Licence as published
 * by the Free Software Foundation.
 * See the COPYING file for more information.
 *
 **********************************************************************/

#pragma once

#include <geos/noding/SegmentIntersector.h> // for inheritance
#include <geos/geom/Coordinate.h> // for composition
#include <geos/noding/SegmentString.h>

#include <vector>

// Forward declarations
namespace geos {
namespace algorithm {
class LineIntersector;
}
namespace noding {
class SegmentString;
}
}

namespace geos {
namespace noding { // geos.noding

/**
 * \brief Finds non-noded intersections in a set of {@link SegmentString}s, if any exist.
 *
 * Non-noded intersections include:
 *
 * - intersections which lie in the interior of a segment
 * - intersections at a vertex in the interior of a SegmentString
 * (e.g. with a segment string endpoint or other interior vertex)
 *
 * @version 1.7
 */
class NodingIntersectionFinder: public SegmentIntersector {

public:

    /** \brief
     * Creates an intersection finder which finds an interior intersection
     * if one exists
     *
     * @param newLi the LineIntersector to use
     */
    NodingIntersectionFinder(algorithm::LineIntersector& newLi)
        :
        li(newLi),
        interiorIntersection(geom::Coordinate::getNull()),
        intersectionCount(0),
        isCheckEndSegmentsOnly(false),
        findAllIntersections(false)
    {
    }

    /** \brief
     * Tests whether an intersection was found.
     *
     * @return true if an intersection was found
     */
    bool
    hasIntersection() const
    {
        return !interiorIntersection.isNull();
    }

    /** \brief
     * Gets the computed location of the intersection.
     * Due to round-off, the location may not be exact.
     *
     * @return the coordinate for the intersection location
     */
    const geom::Coordinate&
    getInteriorIntersection() const
    {
        return interiorIntersection;
    }

    /** \brief
    * Gets the count of intersections found.
    *
    * @return the intersection count
    */
    size_t
    count() const
    {
        return intersectionCount;
    }

    /** \brief
     * Sets whether only end segments should be tested for interior intersection.
     *
     * This is a performance optimization that may be used if the segments
     * have been previously noded by an appropriate algorithm.
     * It may be known that any potential noding failures will occur only in
     * end segments.
     *
     * @param isCESO whether to test only end segments
     */
    void
    setCheckEndSegmentsOnly(bool isCESO)
    {
        isCheckEndSegmentsOnly = isCESO;
    }


    /** \brief
     * Sets whether all intersections should be computed.
     *
     * When this is `false` (the default value) the value of
     * #isDone() is `true` after the first intersection is found.
     *
     * Default is `false`.
     *
     * @param fAI whether all intersections should be computed
     */
    void
    setFindAllIntersections(bool fAI)
    {
        findAllIntersections = fAI;
    }

    /** \brief
     * Gets the endpoints of the intersecting segments.
     *
     * @return an array of the segment endpoints (p00, p01, p10, p11)
     */
    const std::vector<geom::Coordinate>&
    getIntersectionSegments() const
    {
        return intSegments;
    }

    /** \brief
     * This method is called by clients of the SegmentIntersector class to process
     * intersections for two segments of the [SegmentStrings](@ref SegmentString)
     * being intersected.
     *
     * @note Some clients (such as `MonotoneChains`) may optimize away
     * this call for segment pairs which they have determined do not intersect
     * (e.g. by an disjoint envelope test).
     */
    void processIntersections(
        SegmentString* e0,  std::size_t segIndex0,
        SegmentString* e1,  std::size_t segIndex1) override;

    bool
    isDone() const override
    {
        return !interiorIntersection.isNull();
    }

private:
    algorithm::LineIntersector& li;
    geom::Coordinate interiorIntersection;
    std::size_t intersectionCount;
    bool isCheckEndSegmentsOnly;
    bool findAllIntersections;
    std::vector<geom::Coordinate> intSegments;

    // Declare type as noncopyable
    NodingIntersectionFinder(const NodingIntersectionFinder& other) = delete;
    NodingIntersectionFinder& operator=(const NodingIntersectionFinder& rhs) = delete;

    /** \brief
     * Tests if two vertices with at least one in a segmentString interior
     * are equal.
     *
     * @param p0 a segment vertex
     * @param p1 a segment vertex
     * @param isEnd0 true if vertex is a segmentString endpoint
     * @param isEnd1 true if vertex is a segmentString endpoint
     * @return true if an intersection is found
    */
    static bool isInteriorVertexIntersection(
        const geom::Coordinate& p0, const geom::Coordinate& p1,
        bool isEnd0, bool isEnd1)
    {
        // Intersections between endpoints are valid nodes, so not reported
        if (isEnd0 && isEnd1) {
            return false;
        }

        if (p0.equals2D(p1)) {
            return true;
        }

        return false;
    };

    /** \brief
     * Tests if an intersection occurs between a SegmentString interior vertex and another vertex.
     *
     * @note intersections between two endpoint vertices are valid noding,
     * and are not flagged.
     *
     * @param p00 a segment vertex
     * @param p01 a segment vertex
     * @param p10 a segment vertex
     * @param p11 a segment vertex
     * @param isEnd00 true if vertex is a segmentString endpoint
     * @param isEnd01 true if vertex is a segmentString endpoint
     * @param isEnd10 true if vertex is a segmentString endpoint
     * @param isEnd11 true if vertex is a segmentString endpoint
     * @return true if an intersection is found
     */
    static bool isInteriorVertexIntersection(
        const geom::Coordinate& p00, const geom::Coordinate& p01,
        const geom::Coordinate& p10, const geom::Coordinate& p11,
        bool isEnd00, bool isEnd01, bool isEnd10, bool isEnd11)
    {
        if (isInteriorVertexIntersection(p00, p10, isEnd00, isEnd10)) {
            return true;
        }
        if (isInteriorVertexIntersection(p00, p11, isEnd00, isEnd11)) {
            return true;
        }
        if (isInteriorVertexIntersection(p01, p10, isEnd01, isEnd10)) {
            return true;
        }
        if (isInteriorVertexIntersection(p01, p11, isEnd01, isEnd11)) {
            return true;
        }
        return false;
    };

    /** \brief
     * Tests whether a segment in a SegmentString is an end segment.
     * (either the first or last).
     *
     * @param segStr a segment string
     * @param index the index of a segment in the segment string
     * @return true if the segment is an end segment
     */
    static bool isEndSegment(const SegmentString* segStr, std::size_t index)
    {
        if (index == 0) {
            return true;
        }
        if (index >= segStr->size() - 2) {
            return true;
        }
        return false;
    };

};

} // namespace geos.noding
} // namespace geos