QgsMapToPixel Class Reference

Perform transforms between map coordinates and device coordinates. More...

#include <qgsmaptopixel.h>

Public Member Functions
	QgsMapToPixel ()
	Constructor for an invalid QgsMapToPixel.
	QgsMapToPixel (double mapUnitsPerPixel)
	Constructor.
	QgsMapToPixel (double mapUnitsPerPixel, double centerX, double centerY, int widthPixels, int heightPixels, double rotation)
	Constructor.
bool	isValid () const
	Returns true if the object is valid (i.e.
int	mapHeight () const
	Returns current map height in pixels.
double	mapRotation () const
	Returns the current map rotation in degrees (clockwise).
double	mapUnitsPerPixel () const
	Returns the current map units per pixel.
int	mapWidth () const
	Returns the current map width in pixels.
bool	operator!= (const QgsMapToPixel &other) const
bool	operator== (const QgsMapToPixel &other) const
void	setMapRotation (double degrees, double cx, double cy)
	Sets map rotation in degrees (clockwise).
void	setMapUnitsPerPixel (double mapUnitsPerPixel)
	Sets the map units per pixel.
void	setParameters (double mapUnitsPerPixel, double centerX, double centerY, int widthPixels, int heightPixels, double rotation)
	Sets parameters for use in transforming coordinates.
void	setParameters (double mapUnitsPerPixel, double centerX, double centerY, int widthPixels, int heightPixels, double rotation, bool *ok)
	Sets parameters for use in transforming coordinates.
QString	showParameters () const
	Returns a string representation of the parameters used in the transform.
QgsPointXY	toMapCoordinates (double x, double y) const
	Transforms device coordinates to map (world) coordinates.
QgsPointXY	toMapCoordinates (int x, int y) const
	Transforms device coordinates to map (world) coordinates.
QgsPointXY	toMapCoordinates (QPoint p) const
	Transforms device coordinates to map (world) coordinates.
Q_DECL_DEPRECATED QgsPointXY	toMapPoint (double x, double y) const
	Transforms device coordinates to map (world) coordinates.
QTransform	transform () const
	Returns a QTransform encapsulating the map to pixel conversion.
QgsPointXY	transform (const QgsPointXY &p) const
	Transforms a point p from map (world) coordinates to device coordinates.
void	transform (QgsPointXY *p) const
	Transforms a point p from map (world) coordinates to device coordinates in place.
QgsPointXY	transform (qreal x, qreal y) const
	Transforms the point specified by x,y from map (world) coordinates to device coordinates.
void	transformInPlace (double &x, double &y) const
	Transforms device coordinates to map coordinates.
void	transformInPlace (float &x, float &y) const
	Transforms device coordinates to map coordinates.
template<class T >
void	transformInPlace (QVector< T > &x, QVector< T > &y) const
	Transforms device coordinates to map coordinates.
double	xCenter () const
	Returns the center x-coordinate for the transform.
double	yCenter () const
	Returns the center y-coordinate for the transform.

Static Public Member Functions
static QgsMapToPixel	fromScale (double scale, Qgis::DistanceUnit mapUnits, double dpi=96)
	Returns a new QgsMapToPixel created using a specified scale and distance unit.

Detailed Description

Perform transforms between map coordinates and device coordinates.

This class can convert device coordinates to map coordinates and vice versa.

Definition at line 38 of file qgsmaptopixel.h.

Constructor & Destructor Documentation

QgsMapToPixel() [1/3]

QgsMapToPixel::QgsMapToPixel

(

)

Constructor for an invalid QgsMapToPixel.

A manual call to setParameters() is required to initialize the object.

Definition at line 63 of file qgsmaptopixel.cpp.

QgsMapToPixel() [2/3]

QgsMapToPixel::QgsMapToPixel	(	double	mapUnitsPerPixel,
		double	centerX,
		double	centerY,
		int	widthPixels,
		int	heightPixels,
		double	rotation
	)

Constructor.

Parameters

mapUnitsPerPixel	Map units per pixel
centerX	X coordinate of map center, in geographical units
centerY	Y coordinate of map center, in geographical units
widthPixels	Output width, in pixels
heightPixels	Output height, in pixels
rotation	clockwise rotation in degrees

Since

QGIS 2.8

Definition at line 25 of file qgsmaptopixel.cpp.

QgsMapToPixel() [3/3]

QgsMapToPixel::QgsMapToPixel

(

double

mapUnitsPerPixel

)

Constructor.

Parameters

mapUnitsPerPixel

Map units per pixel

Definition at line 45 of file qgsmaptopixel.cpp.

Member Function Documentation

fromScale()

QgsMapToPixel QgsMapToPixel::fromScale ( double  scale, Qgis::DistanceUnit  mapUnits, double  dpi = 96  )

static

Returns a new QgsMapToPixel created using a specified scale and distance unit.

Parameters

scale	map scale denominator, e.g. 1000.0 for a 1:1000 map.
dpi	screen DPI
mapUnits	map units

Returns

matching QgsMapToPixel

Since

QGIS 3.0

Definition at line 56 of file qgsmaptopixel.cpp.

isValid()

bool QgsMapToPixel::isValid ( ) const

inline

Returns true if the object is valid (i.e.

it has parameters set), or false if the object is default constructed with no parameters set.

Since

QGIS 3.22

Definition at line 83 of file qgsmaptopixel.h.

mapHeight()

int QgsMapToPixel::mapHeight ( ) const

inline

Returns current map height in pixels.

See also

mapWidth()

Since

QGIS 2.8

Definition at line 250 of file qgsmaptopixel.h.

mapRotation()

double QgsMapToPixel::mapRotation ( ) const

inline

Returns the current map rotation in degrees (clockwise).

See also

setMapRotation()

Since

QGIS 2.8

Definition at line 272 of file qgsmaptopixel.h.

mapUnitsPerPixel()

double QgsMapToPixel::mapUnitsPerPixel ( ) const

inline

Returns the current map units per pixel.

See also

setMapUnitsPerPixel()

Definition at line 232 of file qgsmaptopixel.h.

mapWidth()

int QgsMapToPixel::mapWidth ( ) const

inline

Returns the current map width in pixels.

The information is only known if setRotation was used.

See also

mapHeight()

Since

QGIS 2.8

Definition at line 242 of file qgsmaptopixel.h.

operator!=()

bool QgsMapToPixel::operator!= ( const QgsMapToPixel &  other ) const

inline

Definition at line 345 of file qgsmaptopixel.h.

operator==()

bool QgsMapToPixel::operator== ( const QgsMapToPixel &  other ) const

inline

Definition at line 332 of file qgsmaptopixel.h.

setMapRotation()

void QgsMapToPixel::setMapRotation	(	double	degrees,
		double	cx,
		double	cy
	)

Sets map rotation in degrees (clockwise).

Calling this method will automatically set the object as valid.

Parameters

degrees	clockwise rotation in degrees
cx	X ordinate of map center in geographical units
cy	Y ordinate of map center in geographical units

See also

mapRotation()

Since

QGIS 2.8

Definition at line 92 of file qgsmaptopixel.cpp.

setMapUnitsPerPixel()

void QgsMapToPixel::setMapUnitsPerPixel

(

double

mapUnitsPerPixel

)

Sets the map units per pixel.

Calling this method will automatically set the object as valid.

Parameters

mapUnitsPerPixel

Map units per pixel

See also

mapUnitsPerPixel()

Definition at line 80 of file qgsmaptopixel.cpp.

setParameters() [1/2]

void QgsMapToPixel::setParameters	(	double	mapUnitsPerPixel,
		double	centerX,
		double	centerY,
		int	widthPixels,
		int	heightPixels,
		double	rotation
	)

Sets parameters for use in transforming coordinates.

Calling this method will automatically set the object as valid.

Parameters

mapUnitsPerPixel	Map units per pixel
centerX	X coordinate of map center, in geographical units
centerY	Y coordinate of map center, in geographical units
widthPixels	Output width, in pixels
heightPixels	Output height, in pixels
rotation	clockwise rotation in degrees

Note

if the specified parameters result in an invalid transform then no changes will be applied to the object

Since

QGIS 2.8

Definition at line 165 of file qgsmaptopixel.cpp.

setParameters() [2/2]

void QgsMapToPixel::setParameters	(	double	mapUnitsPerPixel,
		double	centerX,
		double	centerY,
		int	widthPixels,
		int	heightPixels,
		double	rotation,
		bool *	ok
	)

Sets parameters for use in transforming coordinates.

Calling this method will automatically set the object as valid.

Parameters

mapUnitsPerPixel	Map units per pixel
centerX	X coordinate of map center, in geographical units
centerY	Y coordinate of map center, in geographical units
widthPixels	Output width, in pixels
heightPixels	Output height, in pixels
rotation	clockwise rotation in degrees
ok	will be set to true if the specified parameters result in a valid transform, otherwise the changes are ignored and ok will be set to false.

Since

QGIS 3.20

Definition at line 119 of file qgsmaptopixel.cpp.

showParameters()

QString QgsMapToPixel::showParameters

(

)

const

Returns a string representation of the parameters used in the transform.

Definition at line 177 of file qgsmaptopixel.cpp.

toMapCoordinates() [1/3]

QgsPointXY QgsMapToPixel::toMapCoordinates ( double  x, double  y  ) const

inline

Transforms device coordinates to map (world) coordinates.

Definition at line 184 of file qgsmaptopixel.h.

toMapCoordinates() [2/3]

QgsPointXY QgsMapToPixel::toMapCoordinates ( int  x, int  y  ) const

inline

Transforms device coordinates to map (world) coordinates.

Definition at line 176 of file qgsmaptopixel.h.

toMapCoordinates() [3/3]

QgsPointXY QgsMapToPixel::toMapCoordinates ( QPoint  p ) const

inline

Transforms device coordinates to map (world) coordinates.

Parameters

p	Point to be converted to map cooordinates

Returns

QgsPointXY in map coorndiates

Definition at line 200 of file qgsmaptopixel.h.

toMapPoint()

Q_DECL_DEPRECATED QgsPointXY QgsMapToPixel::toMapPoint ( double  x, double  y  ) const

inline

Transforms device coordinates to map (world) coordinates.

Deprecated:

since QGIS 3.4 use toMapCoordinates instead

Definition at line 211 of file qgsmaptopixel.h.

transform() [1/4]

QTransform QgsMapToPixel::transform

(

)

const

Returns a QTransform encapsulating the map to pixel conversion.

Definition at line 187 of file qgsmaptopixel.cpp.

transform() [2/4]

QgsPointXY QgsMapToPixel::transform ( const QgsPointXY &  p ) const

inline

Transforms a point p from map (world) coordinates to device coordinates.

Parameters

p	Point to transform

Returns

QgsPointXY in device coordinates

Definition at line 90 of file qgsmaptopixel.h.

transform() [3/4]

void QgsMapToPixel::transform ( QgsPointXY *  p ) const

inline

Transforms a point p from map (world) coordinates to device coordinates in place.

Definition at line 101 of file qgsmaptopixel.h.

transform() [4/4]

QgsPointXY QgsMapToPixel::transform ( qreal  x, qreal  y  ) const

inline

Transforms the point specified by x,y from map (world) coordinates to device coordinates.

Parameters

x	x coordinate of point to transform
y	y coordinate of point to transform

Returns

QgsPointXY in device coordinates

Definition at line 116 of file qgsmaptopixel.h.

transformInPlace() [1/3]

void QgsMapToPixel::transformInPlace ( double &  x, double &  y  ) const

inline

Transforms device coordinates to map coordinates.

This method modifies the given coordinates in place. It is intended as a fast way to do the transform.

Definition at line 128 of file qgsmaptopixel.h.

transformInPlace() [2/3]

void QgsMapToPixel::transformInPlace ( float &  x, float &  y  ) const

inline

Transforms device coordinates to map coordinates.

This method modifies the given coordinates in place. It is intended as a fast way to do the transform.

Note

Not available in Python bindings

Definition at line 144 of file qgsmaptopixel.h.

transformInPlace() [3/3]

template<class T >

void QgsMapToPixel::transformInPlace ( QVector< T > &  x, QVector< T > &  y  ) const

inline

Transforms device coordinates to map coordinates.

This method modifies the given coordinates in place. It is intended as a fast way to do the transform.

Note

not available in Python bindings

Definition at line 162 of file qgsmaptopixel.h.

xCenter()

double QgsMapToPixel::xCenter ( ) const

inline

Returns the center x-coordinate for the transform.

See also

yCenter()

Since

QGIS 3.0

Definition at line 323 of file qgsmaptopixel.h.

yCenter()

double QgsMapToPixel::yCenter ( ) const

inline

Returns the center y-coordinate for the transform.

See also

xCenter()

Since

QGIS 3.0

Definition at line 330 of file qgsmaptopixel.h.

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

• /build/qgis-3.34.0+99sid/src/core/qgsmaptopixel.h
• /build/qgis-3.34.0+99sid/src/core/qgsmaptopixel.cpp