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.
	~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.

Private Attributes
double	mDpi
	dpi member
QGis::UnitType	mMapUnits
	map unit member

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

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.

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

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 52 of file qgsscalecalculator.cpp.

References calculateGeographicDistance(), QGis::Degrees, QGis::Feet, mDpi, QGis::Meters, mMapUnits, QgsDebugMsg, QgsRectangle::xMaximum(), and QgsRectangle::xMinimum().

Referenced by QgsComposerMap::scale(), and QgsMapRenderer::updateScale().

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 88 of file qgsscalecalculator.cpp.

References QgsDebugMsg, QgsRectangle::xMaximum(), QgsRectangle::xMinimum(), QgsRectangle::yMaximum(), and QgsRectangle::yMinimum().

Referenced by calculate().

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.

References mDpi.

Referenced by QgsMapRenderer::outputDpi(), QgsMapRenderer::render(), and setDpi().

QGis::UnitType QgsScaleCalculator::mapUnits

(

)

const

Returns current map units.

Definition at line 46 of file qgsscalecalculator.cpp.

References mMapUnits, and QgsDebugMsgLevel.

Referenced by QgsMapRenderer::mapUnits(), and setMapUnits().

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 31 of file qgsscalecalculator.cpp.

References dpi(), and mDpi.

Referenced by QgsComposerMap::scale(), and QgsMapRenderer::setOutputSize().

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 40 of file qgsscalecalculator.cpp.

References mapUnits(), mMapUnits, and QgsDebugMsg.

Referenced by QgsComposerMap::scale(), and QgsMapRenderer::setMapUnits().

Member Data Documentation

double QgsScaleCalculator::mDpi

private

dpi member

Definition at line 87 of file qgsscalecalculator.h.

Referenced by calculate(), dpi(), and setDpi().

QGis::UnitType QgsScaleCalculator::mMapUnits

private

map unit member

Definition at line 90 of file qgsscalecalculator.h.

Referenced by calculate(), mapUnits(), and setMapUnits().

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

• /tmp/buildd/qgis-2.0.1/src/core/qgsscalecalculator.h
• /tmp/buildd/qgis-2.0.1/src/core/qgsscalecalculator.cpp