qgspointlocator.h

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/***************************************************************************
  qgspointlocator.h
  --------------------------------------
  Date                 : November 2014
  Copyright            : (C) 2014 by Martin Dobias
  Email                : wonder dot sk at gmail dot com
 ***************************************************************************
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 ***************************************************************************/

#ifndef QGSPOINTLOCATOR_H
#define QGSPOINTLOCATOR_H

class QgsPoint;
class QgsVectorLayer;

#include "qgsfeature.h"
#include "qgspoint.h"
#include "qgsrectangle.h"

class QgsCoordinateTransform;
class QgsCoordinateReferenceSystem;

class QgsPointLocator_VisitorNearestVertex;
class QgsPointLocator_VisitorNearestEdge;
class QgsPointLocator_VisitorArea;
class QgsPointLocator_VisitorEdgesInRect;

namespace SpatialIndex
{
  class IStorageManager;
  class ISpatialIndex;
}

class CORE_EXPORT QgsPointLocator : public QObject
{
    Q_OBJECT
  public:
    explicit QgsPointLocator( QgsVectorLayer* layer, const QgsCoordinateReferenceSystem* destCRS = nullptr, const QgsRectangle* extent = nullptr );

    ~QgsPointLocator();

    QgsVectorLayer* layer() const { return mLayer; }
    const QgsCoordinateReferenceSystem* destCRS() const;
    const QgsRectangle* extent() const { return mExtent; }
    void setExtent( const QgsRectangle* extent );

    enum Type
    {
      Invalid = 0, 
      Vertex  = 1, 
      Edge    = 2, 
      Area    = 4, 
      All = Vertex | Edge | Area 
    };

    Q_DECLARE_FLAGS( Types, Type )

    
    bool init( int maxFeaturesToIndex = -1 );

    bool hasIndex() const;

    struct Match
    {
      Match()
          : mType( Invalid )
          , mDist( 0 )
          , mPoint()
          , mLayer( nullptr )
          , mFid( 0 )
          , mVertexIndex( 0 )
      {}

      Match( Type t, QgsVectorLayer* vl, QgsFeatureId fid, double dist, const QgsPoint& pt, int vertexIndex = 0, QgsPoint* edgePoints = nullptr )
          : mType( t )
          , mDist( dist )
          , mPoint( pt )
          , mLayer( vl )
          , mFid( fid )
          , mVertexIndex( vertexIndex )
      {
        if ( edgePoints )
        {
          mEdgePoints[0] = edgePoints[0];
          mEdgePoints[1] = edgePoints[1];
        }
      }

      Type type() const { return mType; }

      bool isValid() const { return mType != Invalid; }
      bool hasVertex() const { return mType == Vertex; }
      bool hasEdge() const { return mType == Edge; }
      bool hasArea() const { return mType == Area; }

      double distance() const { return mDist; }

      QgsPoint point() const { return mPoint; }

      int vertexIndex() const { return mVertexIndex; }

      QgsVectorLayer* layer() const { return mLayer; }

      QgsFeatureId featureId() const { return mFid; }

      void edgePoints( QgsPoint& pt1, QgsPoint& pt2 ) const
      {
        pt1 = mEdgePoints[0];
        pt2 = mEdgePoints[1];
      }

    protected:
      Type mType;
      double mDist;
      QgsPoint mPoint;
      QgsVectorLayer* mLayer;
      QgsFeatureId mFid;
      int mVertexIndex; // e.g. vertex index
      QgsPoint mEdgePoints[2];
    };

    typedef class QList<Match> MatchList;

    struct MatchFilter
    {
      virtual ~MatchFilter() {}
      virtual bool acceptMatch( const Match& match ) = 0;
    };

    // intersection queries

    Match nearestVertex( const QgsPoint& point, double tolerance, MatchFilter* filter = nullptr );
    Match nearestEdge( const QgsPoint& point, double tolerance, MatchFilter* filter = nullptr );
    MatchList edgesInRect( const QgsRectangle& rect, MatchFilter* filter = nullptr );
    MatchList edgesInRect( const QgsPoint& point, double tolerance, MatchFilter* filter = nullptr );

    // point-in-polygon query

    // TODO: function to return just the first match?
    MatchList pointInPolygon( const QgsPoint& point );

    //

    int cachedGeometryCount() const { return mGeoms.count(); }

  protected:
    bool rebuildIndex( int maxFeaturesToIndex = -1 );
  protected slots:
    void destroyIndex();
  private slots:
    void onFeatureAdded( QgsFeatureId fid );
    void onFeatureDeleted( QgsFeatureId fid );
    void onGeometryChanged( QgsFeatureId fid, QgsGeometry& geom );

  private:
    SpatialIndex::IStorageManager* mStorage;

    QHash<QgsFeatureId, QgsGeometry*> mGeoms;
    SpatialIndex::ISpatialIndex* mRTree;

    bool mIsEmptyLayer;

    QgsCoordinateTransform* mTransform;
    QgsVectorLayer* mLayer;
    QgsRectangle* mExtent;

    friend class QgsPointLocator_VisitorNearestVertex;
    friend class QgsPointLocator_VisitorNearestEdge;
    friend class QgsPointLocator_VisitorArea;
    friend class QgsPointLocator_VisitorEdgesInRect;
};


#endif // QGSPOINTLOCATOR_H