Class: QgsGeometryGeneratorSymbolLayer

class qgis.core.QgsGeometryGeneratorSymbolLayer

Bases: QgsSymbolLayer

Methods

clone	rtype QgsSymbolLayer
color	rtype QColor
create	Creates the symbol layer
drawPreviewIcon	param context
geometryExpression	Gets the expression to generate this geometry.
hasDataDefinedProperties	rtype bool
isCompatibleWithSymbol	Will always return True.
layerType	rtype str
mapUnitScale	rtype QgsMapUnitScale
outputUnit	rtype QgsUnitTypes.RenderUnit
properties	rtype Dict[str, Any]
render	Will render this symbol layer using the context.
setColor	param color
setGeometryExpression	Set the expression to generate this geometry.
setOutputUnit	param unit
setSubSymbol	param symbol
setSymbolType	Set the type of symbol which should be created.
setUnits	Sets the units for the geometry expression.
startFeatureRender	param feature
startRender	param context
stopFeatureRender	param feature
stopRender	param context
subSymbol	rtype QgsSymbol
symbolType	Access the symbol type.
units	Returns the unit for the geometry expression.
usedAttributes	param context
usesMapUnits	rtype bool

clone(self) → QgsSymbolLayer

Return type

QgsSymbolLayer

color(self) → QColor

Return type

QColor

create(properties: Dict[str, Any]) → QgsSymbolLayer

Creates the symbol layer

Parameters

properties (Dict[str) –

Return type

QgsSymbolLayer

drawPreviewIcon(self, context: QgsSymbolRenderContext, size: QSize)

Parameters

• context (QgsSymbolRenderContext) –

• size (QSize) –

geometryExpression(self) → str

Gets the expression to generate this geometry.

Return type

str

hasDataDefinedProperties(self) → bool

Return type

bool

isCompatibleWithSymbol(self, symbol: QgsSymbol) → bool

Will always return True. This is a hybrid layer, it constructs its own geometry so it does not care about the geometry of its parents.

Parameters

symbol (QgsSymbol) –

Return type

bool

layerType(self) → str

Return type

str

mapUnitScale(self) → QgsMapUnitScale

Return type

QgsMapUnitScale

outputUnit(self) → QgsUnitTypes.RenderUnit

Return type

QgsUnitTypes.RenderUnit

properties(self) → Dict[str, Any]

Return type

Dict[str, Any]

render(self, context: QgsSymbolRenderContext, geometryType: QgsWkbTypes.GeometryType = QgsWkbTypes.GeometryType.UnknownGeometry, points: QPolygonF = None, rings: Iterable[QPolygonF] = [])

Will render this symbol layer using the context. In comparison to other symbols there is no geometry passed in, since the geometry will be created based on information from the context which contains a QgsRenderContext which in turn contains an expression context which is available to the evaluated expression.

Parameters

• context (QgsSymbolRenderContext) – The rendering context which will be used to render and to construct a geometry.

• geometryType (QgsWkbTypes.GeometryType = QgsWkbTypes.GeometryType.UnknownGeometry) – type of original geometry being rendered by the parent symbol (since QGIS 3.22)

• points (QPolygonF = None) – optional list of original points which are being rendered by the parent symbol (since QGIS 3.22)

• rings (Iterable[QPolygonF] = []) – optional list of original rings which are being rendered by the parent symbol (since QGIS 3.22)

setColor(self, color: Union[QColor, Qt.GlobalColor, QGradient])

Parameters

color (Union[QColor) –

setGeometryExpression(self, exp: str)

Set the expression to generate this geometry.

Parameters

exp (str) –

setOutputUnit(self, unit: QgsUnitTypes.RenderUnit)

Parameters

unit (QgsUnitTypes.RenderUnit) –

setSubSymbol(self, symbol: QgsSymbol) → bool

Parameters

symbol (QgsSymbol) –

Return type

bool

setSymbolType(self, symbolType: Qgis.SymbolType)

Set the type of symbol which should be created. Should match with the return type of the expression.

Parameters

symbolType (Qgis.SymbolType) – The symbol type which shall be used below this symbol.

setUnits(self, units: QgsUnitTypes.RenderUnit)

Sets the units for the geometry expression.

By default this is QgsUnitTypes.MapUnits, which means that the geometryExpression() will return geometries in the associated layer’s CRS.

See also

units()

New in version 3.22.

Parameters

units (QgsUnitTypes.RenderUnit) –

startFeatureRender(self, feature: QgsFeature, context: QgsRenderContext)

Parameters

• feature (QgsFeature) –

• context (QgsRenderContext) –

startRender(self, context: QgsSymbolRenderContext)

Parameters

context (QgsSymbolRenderContext) –

stopFeatureRender(self, feature: QgsFeature, context: QgsRenderContext)

Parameters

• feature (QgsFeature) –

• context (QgsRenderContext) –

stopRender(self, context: QgsSymbolRenderContext)

Parameters

context (QgsSymbolRenderContext) –

subSymbol(self) → QgsSymbol

Return type

QgsSymbol

symbolType(self) → Qgis.SymbolType

Access the symbol type. This defines the type of geometry that is created by this generator.

Return type

Qgis.SymbolType

Returns

Symbol type

units(self) → QgsUnitTypes.RenderUnit

Returns the unit for the geometry expression.

By default this is QgsUnitTypes.MapUnits, which means that the geometryExpression() will return geometries in the associated layer’s CRS.

See also

setUnits()

New in version 3.22.

Return type

QgsUnitTypes.RenderUnit

usedAttributes(self, context: QgsRenderContext) → Set[str]

Parameters

context (QgsRenderContext) –

Return type

Set[str]

usesMapUnits(self) → bool

Return type

bool