QGIS API Documentation 3.40.0-Bratislava (b56115d8743)
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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, Qgis::DistanceUnit mapUnits=Qgis::DistanceUnit::Meters) | |
Constructor. | |
double | calculate (const QgsRectangle &mapExtent, double canvasWidth) const |
Calculate the scale denominator. | |
double | calculateGeographicDistance (const QgsRectangle &mapExtent) const |
Calculate the distance between two points in geographic coordinates. | |
QSizeF | calculateImageSize (const QgsRectangle &mapExtent, double scale) const |
Calculate the image size in pixel (physical) units. | |
double | dpi () const |
Returns the DPI (dots per inch) used in scale calculations. | |
Qgis::DistanceUnit | mapUnits () const |
Returns current map units. | |
void | setDpi (double dpi) |
Sets the dpi (dots per inch) for the output resolution, to be used in scale calculations. | |
void | setMapUnits (Qgis::DistanceUnit mapUnits) |
Set the map units. | |
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 , |
Qgis::DistanceUnit | mapUnits = Qgis::DistanceUnit::Meters |
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) |
Constructor.
dpi | Monitor resolution in dots per inch |
mapUnits | Units of the data on the map |
Definition at line 26 of file qgsscalecalculator.cpp.
double QgsScaleCalculator::calculate | ( | const QgsRectangle & | mapExtent, |
double | canvasWidth | ||
) | const |
Calculate the scale denominator.
mapExtent | QgsRectangle containing the current map extent. Units are specified by mapUnits(). |
canvasWidth | Width of the map canvas in pixel (physical) units |
Definition at line 52 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 163 of file qgsscalecalculator.cpp.
QSizeF QgsScaleCalculator::calculateImageSize | ( | const QgsRectangle & | mapExtent, |
double | scale | ||
) | const |
Calculate the image size in pixel (physical) units.
mapExtent | QgsRectangle containing the current map extent. Units are specified by mapUnits() |
scale | Scale denominator, e.g. 1000.0 for a 1:1000 map |
Definition at line 69 of file qgsscalecalculator.cpp.
double QgsScaleCalculator::dpi | ( | ) | const |
Returns the DPI (dots per inch) used in scale calculations.
Definition at line 35 of file qgsscalecalculator.cpp.
Qgis::DistanceUnit QgsScaleCalculator::mapUnits | ( | ) | const |
Returns current map units.
Definition at line 46 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 31 of file qgsscalecalculator.cpp.
void QgsScaleCalculator::setMapUnits | ( | Qgis::DistanceUnit | mapUnits | ) |