Class: QgsMapToPixelSimplifier

Implementation of a geometry simplifier using the “MapToPixel” algorithm.

Simplifies a geometry removing points within of the maximum distance difference that defines the MapToPixel info of a RenderContext request. This class enables simplify the geometries to be rendered in a MapCanvas target to speed up the vector drawing.

Class Hierarchy

Inheritance diagram of qgis.core.QgsMapToPixelSimplifier

Base classes

QgsAbstractGeometrySimplifier

Abstract base class for simplifying geometries using a specific algorithm.
class qgis.core.QgsMapToPixelSimplifier[source]

Bases: QgsAbstractGeometrySimplifier

__init__(simplifyFlags: int, tolerance: float, simplifyAlgorithm: Qgis.VectorSimplificationAlgorithm = Qgis.VectorSimplificationAlgorithm.Distance)

Constructor

Parameters:

  • simplifyFlags (int)

  • tolerance (float)

  • simplifyAlgorithm (Qgis.VectorSimplificationAlgorithm = Qgis.VectorSimplificationAlgorithm.Distance)

__init__(a0: QgsMapToPixelSimplifier)
Parameters:

a0 (QgsMapToPixelSimplifier)

NoFlags = 0
SimplifyEnvelope = 2
class SimplifyFlag

Bases: int

SimplifyGeometry = 1
static calculateLengthSquared2D(x1: float, y1: float, x2: float, y2: float) → float[source]

Returns the squared 2D-distance of the vector defined by the two points specified

Parameters:

  • x1 (float)

  • y1 (float)

  • x2 (float)

  • y2 (float)

Return type:

float

static equalSnapToGrid(x1: float, y1: float, x2: float, y2: float, gridOriginX: float, gridOriginY: float, gridInverseSizeXY: float) → bool[source]

Returns whether the points belong to the same grid

Parameters:

  • x1 (float)

  • y1 (float)

  • x2 (float)

  • y2 (float)

  • gridOriginX (float)

  • gridOriginY (float)

  • gridInverseSizeXY (float)

Return type:

bool

isGeneralizableByMapBoundingBox(envelope: QgsRectangle, map2pixelTol: float) → bool[source]

Returns whether the envelope can be replaced by its BBOX when is applied the specified map2pixel context

isGeneralizableByMapBoundingBox(self, envelope: QgsRectangle) -> bool Returns whether the envelope can be replaced by its BBOX when is applied the specified map2pixel context

Parameters:
Return type:

bool

setSimplifyAlgorithm(self, simplifyAlgorithm: Qgis.VectorSimplificationAlgorithm)[source]

Sets the local simplification algorithm of the vector layer managed

Parameters:

simplifyAlgorithm (Qgis.VectorSimplificationAlgorithm)

setSimplifyFlags(self, simplifyFlags: int)[source]

Sets the simplification hints of the vector layer managed

Parameters:

simplifyFlags (int)

setTolerance(self, value: float)[source]

Sets the tolerance of the vector layer managed

Parameters:

value (float)

simplifyAlgorithm(self) → Qgis.VectorSimplificationAlgorithm[source]

Gets the local simplification algorithm of the vector layer managed

Return type:

Qgis.VectorSimplificationAlgorithm

simplifyFlags(self) → int[source]

Gets the simplification hints of the vector layer managed

Return type:

int