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

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

Detailed Description

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

Constructor & Destructor Documentation

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)

QgsScaleCalculator::~QgsScaleCalculator ( )

Destructor.

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

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

double QgsScaleCalculator::dpi ( )

Accessor for dpi used in scale calculations.

QGis::UnitType QgsScaleCalculator::mapUnits ( ) const

Returns current map units.

void QgsScaleCalculator::setDpi ( double dpi )

Set the dpi to be used in scale calculations.

Parameters

dpi	Dots per inch of monitor resolution

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

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