qgsregularpolygon.h

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/***************************************************************************
                         qgsregularpolygon.h
                         --------------
    begin                : May 2017
    copyright            : (C) 2017 by Loîc Bartoletti
    email                : lbartoletti at tuxfamily dot org
 ***************************************************************************/
 
/***************************************************************************
 *                                                                         *
 *   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 QGSREGULARPOLYGON_H
#define QGSREGULARPOLYGON_H
 
#include <QString>
 
#include "qgis_core.h"
#include "qgspoint.h"
#include "qgspolygon.h"
#include "qgslinestring.h"
#include "qgscircle.h"
#include "qgstriangle.h"
 
 
class CORE_EXPORT QgsRegularPolygon
{
  public:
 
    enum ConstructionOption
    {
      InscribedCircle, //<! Inscribed in a circle (the radius is the distance between the center and vertices)
      CircumscribedCircle //<! Circumscribed about a circle (the radius is the distance from the center to the midpoints of the sides)
    };
 
    QgsRegularPolygon() = default;
 
    QgsRegularPolygon( const QgsPoint &center, double radius, double azimuth, unsigned int numberSides, ConstructionOption circle );
 
    QgsRegularPolygon( const QgsPoint &center, const QgsPoint &pt1, unsigned int numberSides, ConstructionOption circle );
 
    QgsRegularPolygon( const QgsPoint &pt1, const QgsPoint &pt2, unsigned int numberSides );
 
    bool operator ==( const QgsRegularPolygon &rp ) const;
    bool operator !=( const QgsRegularPolygon &rp ) const;
 
    bool isEmpty() const;
 
    QgsPoint center() const { return mCenter; }
 
    double radius() const { return mRadius; }
 
    QgsPoint firstVertex() const { return mFirstVertex; }
 
    double apothem() const { return mRadius * std::cos( M_PI / mNumberSides ); }
 
    unsigned int numberSides() const { return mNumberSides; }
 
    void setCenter( const QgsPoint &center );
 
    void setRadius( double radius );
 
    void setFirstVertex( const QgsPoint &firstVertex );
 
    void setNumberSides( unsigned int numberSides );
 
    QgsPointSequence points() const;
 
    QgsPolygon *toPolygon() const SIP_FACTORY;
 
    QgsLineString *toLineString() const SIP_FACTORY;
 
    QgsTriangle toTriangle() const;
 
    QVector<QgsTriangle> triangulate() const;
 
    QgsCircle inscribedCircle() const;
 
    QgsCircle circumscribedCircle() const;
 
    QString toString( int pointPrecision = 17, int radiusPrecision = 17, int anglePrecision = 2 ) const;
 
    double interiorAngle() const;
 
    double centralAngle() const;
 
    double area() const;
 
    double perimeter() const;
 
    double length() const;
 
  private:
    QgsPoint mCenter;
    QgsPoint mFirstVertex;
    unsigned int mNumberSides = 0;
    double mRadius = 0.0;
 
    double apothemToRadius( double apothem, unsigned int numberSides ) const;
 
    double interiorAngle( unsigned int nbSides ) const;
 
    double centralAngle( unsigned int nbSides ) const;
 
};
 
#endif // QGSREGULARPOLYGON_H