QGIS API Documentation
3.16.0-Hannover (43b64b13f3)
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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, double canvasWidth) const |
Calculate the scale denominator. More... | |
double | calculateGeographicDistance (const QgsRectangle &mapExtent) const |
Calculate the distance between two points in geographic coordinates. More... | |
double | dpi () |
Returns the DPI (dots per inch) used in scale calculations. More... | |
QgsUnitTypes::DistanceUnit | mapUnits () const |
Returns current map units. More... | |
void | setDpi (double dpi) |
Sets the dpi (dots per inch) for the output resolution, to be used in scale calculations. More... | |
void | setMapUnits (QgsUnitTypes::DistanceUnit mapUnits) |
Set the map units. More... | |
Calculates scale for a given combination of canvas size, map extent, and monitor dpi.
Definition at line 34 of file qgsscalecalculator.h.
QgsScaleCalculator::QgsScaleCalculator | ( | double | dpi = 0 , |
QgsUnitTypes::DistanceUnit | mapUnits = QgsUnitTypes::DistanceMeters |
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) |
Constructor.
dpi | Monitor resolution in dots per inch |
mapUnits | Units of the data on the map |
Definition at line 24 of file qgsscalecalculator.cpp.
double QgsScaleCalculator::calculate | ( | const QgsRectangle & | mapExtent, |
double | canvasWidth | ||
) | const |
Calculate the scale denominator.
mapExtent | QgsRectangle containing the current map extent |
canvasWidth | Width of the map canvas in pixel (physical) units |
Definition at line 50 of file qgsscalecalculator.cpp.
double QgsScaleCalculator::calculateGeographicDistance | ( | const QgsRectangle & | mapExtent | ) | const |
Calculate the distance between two points in geographic coordinates.
Used to calculate scale for map views with geographic (decimal degree) data.
mapExtent | QgsRectangle containing the current map extent |
Definition at line 91 of file qgsscalecalculator.cpp.
double QgsScaleCalculator::dpi | ( | ) |
Returns the DPI (dots per inch) used in scale calculations.
Definition at line 33 of file qgsscalecalculator.cpp.
QgsUnitTypes::DistanceUnit QgsScaleCalculator::mapUnits | ( | ) | const |
Returns current map units.
Definition at line 44 of file qgsscalecalculator.cpp.
void QgsScaleCalculator::setDpi | ( | double | dpi | ) |
Sets the dpi (dots per inch) for the output resolution, to be used in scale calculations.
Definition at line 29 of file qgsscalecalculator.cpp.
void QgsScaleCalculator::setMapUnits | ( | QgsUnitTypes::DistanceUnit | mapUnits | ) |
Set the map units.
mapUnits | Units of the data on the map. Must match a value from the |
Definition at line 38 of file qgsscalecalculator.cpp.