QGIS API Documentation  2.99.0-Master (c42dad3)
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, QgsUnitTypes::DistanceUnit mapUnits=QgsUnitTypes::DistanceMeters)
 Constructor. 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...
 
QgsUnitTypes::DistanceUnit mapUnits () const
 Returns current map units. More...
 
void setDpi (double dpi)
 Set the dpi to be used in scale calculations. More...
 
void setMapUnits (QgsUnitTypes::DistanceUnit 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 32 of file qgsscalecalculator.h.

Constructor & Destructor Documentation

§ QgsScaleCalculator()

QgsScaleCalculator::QgsScaleCalculator ( double  dpi = 0,
QgsUnitTypes::DistanceUnit  mapUnits = QgsUnitTypes::DistanceMeters 
)

Constructor.

Parameters
dpiMonitor resolution in dots per inch
mapUnitsUnits of the data on the map

Definition at line 24 of file qgsscalecalculator.cpp.

Member Function Documentation

§ calculate()

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 50 of file qgsscalecalculator.cpp.

§ calculateGeographicDistance()

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 91 of file qgsscalecalculator.cpp.

§ dpi()

double QgsScaleCalculator::dpi ( )

Accessor for dpi used in scale calculations.

Returns
int the dpi used for scale calculations.

Definition at line 33 of file qgsscalecalculator.cpp.

§ mapUnits()

QgsUnitTypes::DistanceUnit QgsScaleCalculator::mapUnits ( ) const

Returns current map units.

Definition at line 44 of file qgsscalecalculator.cpp.

§ setDpi()

void QgsScaleCalculator::setDpi ( double  dpi)

Set the dpi to be used in scale calculations.

Parameters
dpiDots per inch of monitor resolution

Definition at line 29 of file qgsscalecalculator.cpp.

§ setMapUnits()

void QgsScaleCalculator::setMapUnits ( QgsUnitTypes::DistanceUnit  mapUnits)

Set the map units.

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

Definition at line 38 of file qgsscalecalculator.cpp.


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