QGIS API Documentation  3.27.0-Master (aef1b1ec20)
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_core.h"
23 #include "qgis_sip.h"
24 #include "qgsunittypes.h"
25 
26 class QString;
27 class QgsRectangle;
28 
34 class CORE_EXPORT QgsScaleCalculator
35 {
36  public:
37 
43  QgsScaleCalculator( double dpi = 0,
45 
50  void setDpi( double dpi );
51 
56  double dpi() const;
57 
62  void setMapUnits( QgsUnitTypes::DistanceUnit mapUnits );
63 
65  QgsUnitTypes::DistanceUnit mapUnits() const;
66 
73  double calculate( const QgsRectangle &mapExtent, double canvasWidth ) const;
74 
82  QSizeF calculateImageSize( const QgsRectangle &mapExtent, double scale ) const;
83 
90  double calculateGeographicDistance( const QgsRectangle &mapExtent ) const;
91 
92  private:
93 
95  void calculateMetrics( const QgsRectangle &mapExtent, double &delta, double &conversionFactor ) const;
96 
98  double mDpi;
99 
101  QgsUnitTypes::DistanceUnit mMapUnits;
102 };
103 
104 #endif // #ifndef QGSSCALECALCULATOR_H
A rectangle specified with double values.
Definition: qgsrectangle.h:42
Calculates scale for a given combination of canvas size, map extent, and monitor dpi.
DistanceUnit
Units of distance.
Definition: qgsunittypes.h:68
@ DistanceMeters
Meters.
Definition: qgsunittypes.h:69