qgssnapper.h

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/***************************************************************************
                              qgssnapper.h
                              ------------
  begin                : June 7, 2007
  copyright            : (C) 2007 by Marco Hugentobler
  email                : marco dot hugentobler at karto dot baug dot ethz dot ch
 ***************************************************************************/

/***************************************************************************
 *                                                                         *
 *   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 QGSSNAPPER_H
#define QGSSNAPPER_H

#include "qgspoint.h"
#include "qgstolerance.h"
#include "qgsfeature.h"

#include <QList>
#include <QMultiMap>

class QgsMapRenderer;
class QgsVectorLayer;
class QPoint;

struct CORE_EXPORT QgsSnappingResult
{
  QgsPoint snappedVertex;
  int snappedVertexNr;
  QgsPoint beforeVertex;
  int beforeVertexNr;
  QgsPoint afterVertex;
  int afterVertexNr;
  QgsFeatureId snappedAtGeometry;
  const QgsVectorLayer* layer;
};



class CORE_EXPORT QgsSnapper
{
  public:
    enum SnappingType
    {
      SnapToVertex,
      SnapToSegment,
      //snap to vertex and also to segment if no vertex is within the search tolerance
      SnapToVertexAndSegment
    };

    enum SnappingMode
    {
      SnapWithOneResult,
      SnapWithResultsForSamePosition,
      SnapWithResultsWithinTolerances
    };

    struct SnapLayer
    {
      QgsVectorLayer* mLayer;
      double mTolerance;
      QgsSnapper::SnappingType mSnapTo;
      QgsTolerance::UnitType mUnitType;
    };

    QgsSnapper( QgsMapRenderer* mapRender );
    ~QgsSnapper();
    int snapPoint( const QPoint& startPoint, QList<QgsSnappingResult>& snappingResult, const QList<QgsPoint>& excludePoints = QList<QgsPoint>() );

    //setters
    void setSnapLayers( const QList<QgsSnapper::SnapLayer>& snapLayers );
    void setSnapMode( QgsSnapper::SnappingMode snapMode );

  private:
    QgsSnapper();

    void cleanResultList( QMultiMap<double, QgsSnappingResult>& list, const QList<QgsPoint>& excludeList ) const;

    QgsMapRenderer* mMapRenderer;
    QgsSnapper::SnappingMode mSnapMode;
    QList<QgsSnapper::SnapLayer> mSnapLayers;
};

#endif