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.
QRectF	transformBounds (const QRectF &bounds) const
	Transforms a bounding box from map coordinates to device coordinates.
void	transformInPlace (double &x, double &y) const
	Transforms map coordinates to device coordinates.
void	transformInPlace (float &x, float &y) const
	Transforms map coordinates to device coordinates.
template<class T>
void	transformInPlace (QVector< T > &x, QVector< T > &y) const
	Transforms map coordinates to device 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 37 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 64 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

Definition at line 26 of file qgsmaptopixel.cpp.

◆ QgsMapToPixel() [3/3]

QgsMapToPixel::QgsMapToPixel ( double mapUnitsPerPixel )

Constructor.

Parameters

mapUnitsPerPixel Map units per pixel

Definition at line 46 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

Definition at line 57 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 80 of file qgsmaptopixel.h.

◆ mapHeight()

int QgsMapToPixel::mapHeight ( ) const

inline

Returns current map height in pixels.

See also: mapWidth()

Definition at line 275 of file qgsmaptopixel.h.

◆ mapRotation()

double QgsMapToPixel::mapRotation ( ) const

inline

Returns the current map rotation in degrees (clockwise).

See also: setMapRotation()

Definition at line 295 of file qgsmaptopixel.h.

◆ mapUnitsPerPixel()

double QgsMapToPixel::mapUnitsPerPixel ( ) const

inline

Returns the current map units per pixel.

See also: setMapUnitsPerPixel()

Definition at line 259 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()

Definition at line 268 of file qgsmaptopixel.h.

◆ operator!=()

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

inline

Definition at line 365 of file qgsmaptopixel.h.

◆ operator==()

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

inline

Definition at line 352 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()

Definition at line 93 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 81 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

Definition at line 166 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 120 of file qgsmaptopixel.cpp.

◆ showParameters()

QString QgsMapToPixel::showParameters ( ) const

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

Definition at line 178 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 211 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 203 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 227 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: QGIS 3.4. Use toMapCoordinates() instead.

Definition at line 238 of file qgsmaptopixel.h.

◆ transform() [1/4]

QTransform QgsMapToPixel::transform ( ) const

Returns a QTransform encapsulating the map to pixel conversion.

Definition at line 188 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 87 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 98 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 113 of file qgsmaptopixel.h.

◆ transformBounds()

QRectF QgsMapToPixel::transformBounds ( const QRectF & bounds ) const

inline

Transforms a bounding box from map coordinates to device coordinates.

The returns bounding box will always completely enclose the transformed input bounding box (i.e. this method will grow the bounds wherever required).

Since: QGIS 3.40

Definition at line 141 of file qgsmaptopixel.h.

◆ transformInPlace() [1/3]

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

inline

Transforms map coordinates to device coordinates.

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

Definition at line 125 of file qgsmaptopixel.h.

◆ transformInPlace() [2/3]

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

inline

Transforms map coordinates to device 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 171 of file qgsmaptopixel.h.

◆ transformInPlace() [3/3]

template<class T>

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

inline

Transforms map coordinates to device 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 189 of file qgsmaptopixel.h.

◆ xCenter()

double QgsMapToPixel::xCenter ( ) const

inline

Returns the center x-coordinate for the transform.

See also: yCenter()

Definition at line 344 of file qgsmaptopixel.h.

◆ yCenter()

double QgsMapToPixel::yCenter ( ) const

inline

Returns the center y-coordinate for the transform.

See also: xCenter()

Definition at line 350 of file qgsmaptopixel.h.

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

/build/qgis-3.99.0+git20251205+26c88405ac0+99sid/src/core/qgsmaptopixel.h
/build/qgis-3.99.0+git20251205+26c88405ac0+99sid/src/core/qgsmaptopixel.cpp

Public Member Functions

Static Public Member Functions

Detailed Description

Constructor & Destructor Documentation

◆ QgsMapToPixel() [1/3]

◆ QgsMapToPixel() [2/3]

◆ QgsMapToPixel() [3/3]

Member Function Documentation

◆ fromScale()

◆ isValid()

◆ mapHeight()

◆ mapRotation()

◆ mapUnitsPerPixel()

◆ mapWidth()

◆ operator!=()

◆ operator==()

◆ setMapRotation()

◆ setMapUnitsPerPixel()

◆ setParameters() [1/2]

◆ setParameters() [2/2]

◆ showParameters()

◆ toMapCoordinates() [1/3]

◆ toMapCoordinates() [2/3]

◆ toMapCoordinates() [3/3]

◆ toMapPoint()

◆ transform() [1/4]

◆ transform() [2/4]

◆ transform() [3/4]

◆ transform() [4/4]

◆ transformBounds()

◆ transformInPlace() [1/3]

◆ transformInPlace() [2/3]

◆ transformInPlace() [3/3]

◆ xCenter()

◆ yCenter()