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

Constructor.

Parameters

dpi	Monitor resolution in dots per inch
mapUnits	Units 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.

Member Function Documentation

calculate()

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

Calculate the scale denominator.

Parameters

mapExtent	QgsRectangle containing the current map extent
canvasWidth	Width 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

mapExtent

QgsRectangle 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()

QGis::UnitType 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

dpi	Dots per inch of monitor resolution

Definition at line 29 of file qgsscalecalculator.cpp.

setMapUnits()

void QgsScaleCalculator::setMapUnits

(

QGis::UnitType

mapUnits

)

Set the map units.

Parameters

mapUnits

Units of the data on the map. Must match a value from the

Definition at line 38 of file qgsscalecalculator.cpp.

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

• /tmp/buildd/qgis-2.18.21+99unstable/src/core/qgsscalecalculator.h
• /tmp/buildd/qgis-2.18.21+99unstable/src/core/qgsscalecalculator.cpp