Class: QgsMapToPixel

Perform transforms between map coordinates and device coordinates.

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

Methods

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.
transformBounds	Transforms a bounding box from map coordinates to device coordinates.
transformInPlace	Transforms map coordinates to device coordinates.
xCenter	Returns the center x-coordinate for the transform.
yCenter	Returns the center y-coordinate for the transform.

Static Methods

fromScale

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

class qgis.core.QgsMapToPixel

Bases: object

__init__()

Constructor for an invalid QgsMapToPixel.

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

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

Constructor

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

__init__(mapUnitsPerPixel: float)

Constructor

Parameters:

mapUnitsPerPixel (float) – Map units per pixel

__init__(a0: QgsMapToPixel)

Parameters:

a0 (QgsMapToPixel)

static 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.

Added 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.

See also

setMapUnitsPerPixel()

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

See also

mapUnitsPerPixel()

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.

Parameters:

• x (int)

• y (int)

Return type:

QgsPointXY

toMapCoordinates(self, p: QPoint) → QgsPointXY

Transforms device coordinates to map (world) coordinates.

Parameters:

p (QPoint) – Point to be converted to map cooordinates

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 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

Return type:

QgsPointXY

Returns:

QgsPointXY in device coordinates

transform(self, p: QgsPointXY | None)

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

Parameters:

p (Optional[QgsPointXY])

transform(self, x: float, y: float) → QgsPointXY

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

Parameters:

• x (float) – x coordinate of point to transform

• y (float) – 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.

Return type:

QTransform

transformBounds(self, bounds: QRectF) → QRectF

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).

Added in version 3.40.

Parameters:

bounds (QRectF)

Return type:

QRectF

transformInPlace(self)

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.

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