qgsscalecalculator.h

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/***************************************************************************
                          qgsscalecalculator.h
              Calculates scale based on map extent and units
                             -------------------
    begin                : May 18, 2004
    copyright            : (C) 2004 by Gary E.Sherman
    email                : sherman at mrcc.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 QGSSCALECALCULATOR_H
#define QGSSCALECALCULATOR_H
 
#include "qgis.h"
#include "qgis_core.h"
#include "qgis_sip.h"
 
class QString;
class QgsRectangle;

class CORE_EXPORT QgsScaleCalculator
{
  public:
    QgsScaleCalculator( double dpi = 0, Qgis::DistanceUnit mapUnits = Qgis::DistanceUnit::Meters );
 

    Qgis::ScaleCalculationMethod method() const { return mMethod; }

    void setMethod( Qgis::ScaleCalculationMethod method );

    void setDpi( double dpi );

    double dpi() const;

    void setMapUnits( Qgis::DistanceUnit mapUnits );

    Qgis::DistanceUnit mapUnits() const;

    double calculate( const QgsRectangle &mapExtent, double canvasWidth ) const;

    QSizeF calculateImageSize( const QgsRectangle &mapExtent, double scale ) const;

    double calculateGeographicDistance( const QgsRectangle &mapExtent ) const;

    double calculateGeographicDistanceAtLatitude( double latitude, double longitude1, double longitude2 ) const;
 
  private:
    void calculateMetrics( const QgsRectangle &mapExtent, double &delta, double &conversionFactor ) const;
 
    // Must be horizontal middle by default, for stable API compatibility
    Qgis::ScaleCalculationMethod mMethod = Qgis::ScaleCalculationMethod::HorizontalMiddle;

    double mDpi = 96;

    Qgis::DistanceUnit mMapUnits = Qgis::DistanceUnit::Unknown;
};
 
#endif // #ifndef QGSSCALECALCULATOR_H