QGIS API Documentation  2.13.0-Master
qgsscalecalculator.h
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1 /***************************************************************************
2  qgsscalecalculator.h
3  Calculates scale based on map extent and units
4  -------------------
5  begin : May 18, 2004
6  copyright : (C) 2004 by Gary E.Sherman
7  email : sherman at mrcc.com
8  ***************************************************************************/
9 
10 /***************************************************************************
11  * *
12  * This program is free software; you can redistribute it and/or modify *
13  * it under the terms of the GNU General Public License as published by *
14  * the Free Software Foundation; either version 2 of the License, or *
15  * (at your option) any later version. *
16  * *
17  ***************************************************************************/
18 
19 #ifndef QGSSCALECALCULATOR_H
20 #define QGSSCALECALCULATOR_H
21 
22 #include <qgis.h>
23 
24 class QString;
25 class QgsRectangle;
26 
31 class CORE_EXPORT QgsScaleCalculator
32 {
33  public:
34 
41  QgsScaleCalculator( double dpi = 0,
42  QGis::UnitType mapUnits = QGis::Meters );
43 
48  void setDpi( double dpi );
49 
54  double dpi();
55 
60  void setMapUnits( QGis::UnitType mapUnits );
61 
63  QGis::UnitType mapUnits() const;
64 
71  double calculate( const QgsRectangle &mapExtent, int canvasWidth );
72 
79  double calculateGeographicDistance( const QgsRectangle &mapExtent );
80 
81  private:
82 
84  double mDpi;
85 
87  QGis::UnitType mMapUnits;
88 };
89 
90 #endif // #ifndef QGSSCALECALCULATOR_H
A rectangle specified with double values.
Definition: qgsrectangle.h:35
UnitType
Map units that qgis supports.
Definition: qgis.h:155
Calculates scale for a given combination of canvas size, map extent, and monitor dpi.