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Public Member Functions | List of all members
QgsScaleCalculator Class Reference

Calculates scale for a given combination of canvas size, map extent, and monitor dpi. More...

#include <qgsscalecalculator.h>

Public Member Functions

 QgsScaleCalculator (double dpi=0, QGis::UnitType mapUnits=QGis::Meters)
 Constructor. More...
 
 ~QgsScaleCalculator ()
 Destructor. More...
 
double calculate (const QgsRectangle &mapExtent, int canvasWidth)
 Calculate the scale denominator. More...
 
double calculateGeographicDistance (const QgsRectangle &mapExtent)
 Calculate the distance between two points in geographic coordinates. More...
 
double dpi ()
 Accessor for dpi used in scale calculations. More...
 
QGis::UnitType mapUnits () const
 Returns current map units. More...
 
void setDpi (double dpi)
 Set the dpi to be used in scale calculations. More...
 
void setMapUnits (QGis::UnitType mapUnits)
 Set the map units. More...
 

Detailed Description

Calculates scale for a given combination of canvas size, map extent, and monitor dpi.

Definition at line 31 of file qgsscalecalculator.h.

Constructor & Destructor Documentation

QgsScaleCalculator::QgsScaleCalculator ( double  dpi = 0,
QGis::UnitType  mapUnits = QGis::Meters 
)

Constructor.

Parameters
dpiMonitor resolution in dots per inch
mapUnitsUnits of the data on the map. Must match a value from the QGis::UnitType enum (Meters, Feet, Degrees)

Definition at line 24 of file qgsscalecalculator.cpp.

QgsScaleCalculator::~QgsScaleCalculator ( )

Destructor.

Definition at line 28 of file qgsscalecalculator.cpp.

Member Function Documentation

double QgsScaleCalculator::calculate ( const QgsRectangle mapExtent,
int  canvasWidth 
)

Calculate the scale denominator.

Parameters
mapExtentQgsRectangle containing the current map extent
canvasWidthWidth of the map canvas in pixel (physical) units
Returns
scale denominator of current map view

Definition at line 52 of file qgsscalecalculator.cpp.

double QgsScaleCalculator::calculateGeographicDistance ( const QgsRectangle mapExtent)

Calculate the distance between two points in geographic coordinates.

Used to calculate scale for map views with geographic (decimal degree) data.

Parameters
mapExtentQgsRectangle containing the current map extent

Definition at line 93 of file qgsscalecalculator.cpp.

double QgsScaleCalculator::dpi ( )

Accessor for dpi used in scale calculations.

Returns
int the dpi used for scale calculations.

Definition at line 35 of file qgsscalecalculator.cpp.

QGis::UnitType QgsScaleCalculator::mapUnits ( ) const

Returns current map units.

Definition at line 46 of file qgsscalecalculator.cpp.

void QgsScaleCalculator::setDpi ( double  dpi)

Set the dpi to be used in scale calculations.

Parameters
dpiDots per inch of monitor resolution

Definition at line 31 of file qgsscalecalculator.cpp.

void QgsScaleCalculator::setMapUnits ( QGis::UnitType  mapUnits)

Set the map units.

Parameters
mapUnitsUnits of the data on the map. Must match a value from the

Definition at line 40 of file qgsscalecalculator.cpp.


The documentation for this class was generated from the following files: