Class: QgsMapToPixel

class qgis.core.QgsMapToPixel

Bases: sip.wrapper

Perform transforms between map coordinates and device coordinates.

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

QgsMapToPixel() Constructor for an invalid QgsMapToPixel.

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

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

QgsMapToPixel(mapUnitsPerPixel: float) Constructor

Parameters:

mapUnitsPerPixel – Map units per pixel

QgsMapToPixel(QgsMapToPixel)

Methods

fromScale

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

isValid

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.

mapHeight

Returns current map height in pixels

mapRotation

Returns the current map rotation in degrees (clockwise).

mapUnitsPerPixel

Returns the current map units per pixel.

mapWidth

Returns the current map width in pixels.

setMapRotation

Sets map rotation in degrees (clockwise).

setMapUnitsPerPixel

Sets the map units per pixel.

setParameters

Sets parameters for use in transforming coordinates.

showParameters

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

toMapCoordinates

Transforms device coordinates to map (world) coordinates.

toMapCoordinatesF

Transforms device coordinates to map (world) coordinates.

toMapPoint

Transforms device coordinates to map (world) coordinates.

transform

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

transformInPlace

Transforms device coordinates to map coordinates.

xCenter

Returns the center x-coordinate for the transform.

yCenter

Returns the center y-coordinate for the transform.

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

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

Parameters:
  • scale (float) – map scale denominator, e.g. 1000.0 for a 1:1000 map.

  • dpi (float = 96) – screen DPI

  • mapUnits (Qgis.DistanceUnit) – map units

Return type:

QgsMapToPixel

Returns:

matching QgsMapToPixel

isValid(self) bool

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.

New in version 3.22.

Return type:

bool

mapHeight(self) int

Returns current map height in pixels

See also

mapWidth()

Return type:

int

mapRotation(self) float

Returns the current map rotation in degrees (clockwise).

See also

setMapRotation()

Return type:

float

mapUnitsPerPixel(self) float

Returns the current map units per pixel.

Return type:

float

mapWidth(self) int

Returns the current map width in pixels.

The information is only known if setRotation was used.

See also

mapHeight()

Return type:

int

setMapRotation(self, degrees: float, cx: float, cy: float)

Sets map rotation in degrees (clockwise).

Calling this method will automatically set the object as valid.

Parameters:
  • degrees (float) – clockwise rotation in degrees

  • cx (float) – X ordinate of map center in geographical units

  • cy (float) – Y ordinate of map center in geographical units

See also

mapRotation()

setMapUnitsPerPixel(self, mapUnitsPerPixel: float)

Sets the map units per pixel.

Calling this method will automatically set the object as valid.

Parameters:

mapUnitsPerPixel (float) – Map units per pixel

setParameters(self, mapUnitsPerPixel: float, centerX: float, centerY: float, widthPixels: int, heightPixels: int, rotation: float)

Sets parameters for use in transforming coordinates.

Calling this method will automatically set the object as valid.

Parameters:
  • mapUnitsPerPixel (float) – Map units per pixel

  • centerX (float) – X coordinate of map center, in geographical units

  • centerY (float) – Y coordinate of map center, in geographical units

  • widthPixels (int) – Output width, in pixels

  • heightPixels (int) – Output height, in pixels

  • rotation (float) – clockwise rotation in degrees

Note

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

showParameters(self) str

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

Return type:

str

toMapCoordinates(self, x: int, y: int) QgsPointXY

Transforms device coordinates to map (world) coordinates.

toMapCoordinates(self, p: QPoint) -> QgsPointXY Transforms device coordinates to map (world) coordinates.

Parameters:
  • p – Point to be converted to map cooordinates

  • x (int) –

  • y (int) –

Return type:

QgsPointXY

Returns:

QgsPointXY in map coorndiates

toMapCoordinatesF(self, x: float, y: float) QgsPointXY

Transforms device coordinates to map (world) coordinates.

Parameters:
  • x (float) –

  • y (float) –

Return type:

QgsPointXY

toMapPoint(self, x: float, y: float) QgsPointXY

Transforms device coordinates to map (world) coordinates.

Deprecated since version QGIS: 3.4 use toMapCoordinates instead

Parameters:
  • x (float) –

  • y (float) –

Return type:

QgsPointXY

transform(self, p: QgsPointXY) QgsPointXY

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

Parameters:

p (QgsPointXY) – Point to transform

Returns:

QgsPointXY in device coordinates

transform(self, p: QgsPointXY) Transforms a point p from map (world) coordinates to device coordinates in place.

transform(self, x: float, y: float) -> QgsPointXY 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

Return type:

QgsPointXY

Returns:

QgsPointXY in device coordinates

transform(self) -> QTransform Returns a QTransform encapsulating the map to pixel conversion.

transformInPlace(self) Tuple[float, float]

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.

Return type:

Tuple[float, float]

xCenter(self) float

Returns the center x-coordinate for the transform.

See also

yCenter()

Return type:

float

yCenter(self) float

Returns the center y-coordinate for the transform.

See also

xCenter()

Return type:

float