A symbol layer subclass which alters rendered feature shapes through the use of QGIS expressions. More...

#include <qgsgeometrygeneratorsymbollayer.h>

Inheritance diagram for QgsGeometryGeneratorSymbolLayer:

Public Member Functions
	~QgsGeometryGeneratorSymbolLayer () override

QgsSymbolLayer *	clone () const override
	Shall be reimplemented by subclasses to create a deep copy of the instance.

QColor	color () const override
	Returns the "representative" color of the symbol layer.

void	drawPreviewIcon (QgsSymbolRenderContext &context, QSize size) override

QString	geometryExpression () const
	Gets the expression to generate this geometry.

bool	hasDataDefinedProperties () const override
	Returns `true` if the symbol layer (or any of its sub-symbols) contains data defined properties.

bool	isCompatibleWithSymbol (QgsSymbol *symbol) const override
	Will always return `true`.

QString	layerType () const override
	Returns a string that represents this layer type.

QgsMapUnitScale	mapUnitScale () const override

Qgis::RenderUnit	outputUnit () const override
	Returns the units to use for sizes and widths within the symbol layer.

QVariantMap	properties () const override
	Should be reimplemented by subclasses to return a string map that contains the configuration information for the symbol layer.

void	render (QgsSymbolRenderContext &context, Qgis::GeometryType geometryType=Qgis::GeometryType::Unknown, const QPolygonF points=nullptr, const QVector< QPolygonF > rings=nullptr)
	Will render this symbol layer using the context.

void	setColor (const QColor &color) override
	Sets the "representative" color for the symbol layer.

void	setGeometryExpression (const QString &exp)
	Set the expression to generate this geometry.

void	setOutputUnit (Qgis::RenderUnit unit) override
	Sets the units to use for sizes and widths within the symbol layer.

bool	setSubSymbol (QgsSymbol *symbol) override
	Sets layer's subsymbol. takes ownership of the passed symbol.

void	setSymbolType (Qgis::SymbolType symbolType)
	Set the type of symbol which should be created.

void	setUnits (Qgis::RenderUnit units)
	Sets the units for the geometry expression.

void	startFeatureRender (const QgsFeature &feature, QgsRenderContext &context) override
	Called before the layer will be rendered for a particular feature.

void	startRender (QgsSymbolRenderContext &context) override
	Called before a set of rendering operations commences on the supplied render context.

void	stopFeatureRender (const QgsFeature &feature, QgsRenderContext &context) override
	Called after the layer has been rendered for a particular feature.

void	stopRender (QgsSymbolRenderContext &context) override
	Called after a set of rendering operations has finished on the supplied render context.

QgsSymbol *	subSymbol () override
	Returns the symbol's sub symbol, if present.

Qgis::SymbolType	symbolType () const
	Access the symbol type.

Qgis::RenderUnit	units () const
	Returns the unit for the geometry expression.

QSet< QString >	usedAttributes (const QgsRenderContext &context) const override
	Returns the set of attributes referenced by the layer.

bool	usesMapUnits () const override
	Returns `true` if the symbol layer has any components which use map unit based sizes.

Public Member Functions inherited from QgsSymbolLayer
virtual	~QgsSymbolLayer ()

virtual bool	canCauseArtifactsBetweenAdjacentTiles () const
	Returns `true` if the symbol layer rendering can cause visible artifacts across a single feature when the feature is rendered as a series of adjacent map tiles each containing a portion of the feature's geometry.

QgsPropertyCollection &	dataDefinedProperties ()
	Returns a reference to the symbol layer's property collection, used for data defined overrides.

const QgsPropertyCollection &	dataDefinedProperties () const
	Returns a reference to the symbol layer's property collection, used for data defined overrides.

virtual double	dxfAngle (QgsSymbolRenderContext &context) const
	Gets angle.

virtual QColor	dxfBrushColor (QgsSymbolRenderContext &context) const
	Gets brush/fill color.

virtual Qt::BrushStyle	dxfBrushStyle () const
	Gets brush/fill style.

virtual QColor	dxfColor (QgsSymbolRenderContext &context) const
	Gets color.

virtual QVector< qreal >	dxfCustomDashPattern (Qgis::RenderUnit &unit) const
	Gets dash pattern.

virtual double	dxfOffset (const QgsDxfExport &e, QgsSymbolRenderContext &context) const
	Gets offset.

virtual Qt::PenStyle	dxfPenStyle () const
	Gets pen style.

virtual double	dxfSize (const QgsDxfExport &e, QgsSymbolRenderContext &context) const
	Gets marker size.

virtual double	dxfWidth (const QgsDxfExport &e, QgsSymbolRenderContext &context) const
	Gets line width.

bool	enabled () const
	Returns `true` if symbol layer is enabled and will be drawn.

virtual double	estimateMaxBleed (const QgsRenderContext &context) const
	Returns the estimated maximum distance which the layer style will bleed outside the drawn shape when drawn in the specified /a context.

virtual QColor	fillColor () const
	Returns the fill color for the symbol layer.

virtual Qgis::SymbolLayerFlags	flags () const
	Returns flags which control the symbol layer's behavior.

QString	id () const
	Returns symbol layer identifier This id is unique in the whole project.

bool	installMasks (QgsRenderContext &context, bool recursive, const QRectF &rect=QRectF())
	When rendering, install masks on context painter.

bool	isLocked () const
	Returns `true` if the symbol layer colors are locked and the layer will ignore any symbol-level color changes.

virtual QList< QgsSymbolLayerReference >	masks () const
	Returns masks defined by this symbol layer.

virtual QString	ogrFeatureStyle (double mmScaleFactor, double mapUnitScaleFactor) const

QgsSymbolLayer &	operator= (const QgsSymbolLayer &other)=delete

QgsPaintEffect *	paintEffect () const
	Returns the current paint effect for the layer.

virtual void	prepareExpressions (const QgsSymbolRenderContext &context)
	Prepares all data defined property expressions for evaluation.

virtual void	prepareMasks (const QgsSymbolRenderContext &context)
	Prepares all mask internal objects according to what is defined in context This should be called prior to calling startRender() method.

int	renderingPass () const
	Specifies the rendering pass in which this symbol layer should be rendered.

void	setDataDefinedProperties (const QgsPropertyCollection &collection)
	Sets the symbol layer's property collection, used for data defined overrides.

virtual void	setDataDefinedProperty (Property key, const QgsProperty &property)
	Sets a data defined property for the layer.

void	setEnabled (bool enabled)
	Sets whether symbol layer is enabled and should be drawn.

virtual void	setFillColor (const QColor &color)
	Sets the fill color for the symbol layer.

void	setId (const QString &id)
	Set symbol layer identifier This id has to be unique in the whole project.

void	setLocked (bool locked)
	Sets whether the layer's colors are locked.

virtual void	setMapUnitScale (const QgsMapUnitScale &scale)

void	setPaintEffect (QgsPaintEffect *effect)
	Sets the current paint effect for the layer.

void	setRenderingPass (int renderingPass)
	Specifies the rendering pass in which this symbol layer should be rendered.

virtual void	setStrokeColor (const QColor &color)
	Sets the stroke color for the symbol layer.

void	setUserFlags (Qgis::SymbolLayerUserFlags flags)
	Sets user-controlled flags which control the symbol layer's behavior.

virtual QColor	strokeColor () const
	Returns the stroke color for the symbol layer.

virtual void	toSld (QDomDocument &doc, QDomElement &element, const QVariantMap &props) const
	Saves the symbol layer as SLD.

Qgis::SymbolType	type () const

Qgis::SymbolLayerUserFlags	userFlags () const
	Returns user-controlled flags which control the symbol layer's behavior.

virtual bool	writeDxf (QgsDxfExport &e, double mmMapUnitScaleFactor, const QString &layerName, QgsSymbolRenderContext &context, QPointF shift=QPointF(0.0, 0.0)) const
	write as DXF

Static Public Member Functions
static QgsSymbolLayer *	create (const QVariantMap &properties)
	Creates the symbol layer.

Static Public Member Functions inherited from QgsSymbolLayer
static const QgsPropertiesDefinition &	propertyDefinitions ()
	Returns the symbol layer property definitions.

Additional Inherited Members
Public Types inherited from QgsSymbolLayer
enum class	Property : int { Size = 0 , Angle , Name , FillColor , StrokeColor , StrokeWidth , StrokeStyle , Offset , Character , Width , Height , PreserveAspectRatio , FillStyle , JoinStyle , SecondaryColor , LineAngle , LineDistance , GradientType , CoordinateMode , GradientSpread , GradientReference1X , GradientReference1Y , GradientReference2X , GradientReference2Y , GradientReference1IsCentroid , GradientReference2IsCentroid , BlurRadius , ShapeburstUseWholeShape , ShapeburstMaxDistance , ShapeburstIgnoreRings , File , DistanceX , DistanceY , DisplacementX , DisplacementY , Opacity , CustomDash , CapStyle , Placement , Interval , OffsetAlongLine , AverageAngleLength , HorizontalAnchor , VerticalAnchor , LayerEnabled , ArrowWidth , ArrowStartWidth , ArrowHeadLength , ArrowHeadThickness , ArrowHeadType , ArrowType , OffsetX , OffsetY , PointCount , RandomSeed , ClipPoints , DensityArea , FontFamily , FontStyle , DashPatternOffset , TrimStart , TrimEnd , LineStartWidthValue , LineEndWidthValue , LineStartColorValue , LineEndColorValue , MarkerClipping , RandomOffsetX , RandomOffsetY , LineClipping , SkipMultiples , ShowMarker }
	Data definable properties. More...

Protected Member Functions inherited from QgsSymbolLayer
	QgsSymbolLayer (const QgsSymbolLayer &other)

	QgsSymbolLayer (Qgis::SymbolType type, bool locked=false)
	Constructor for QgsSymbolLayer.

void	copyDataDefinedProperties (QgsSymbolLayer *destLayer) const
	Copies all data defined properties of this layer to another symbol layer.

void	copyPaintEffect (QgsSymbolLayer *destLayer) const
	Copies paint effect of this layer to another symbol layer.

void	removeMasks (QgsRenderContext &context, bool recursive)
	When rendering, remove previously installed masks from context painter if recursive is `true` masks are removed recursively for all children symbol layers.

void	restoreOldDataDefinedProperties (const QVariantMap &stringMap)
	Restores older data defined properties from string map.

bool	shouldRenderUsingSelectionColor (const QgsSymbolRenderContext &context) const
	Returns `true` if the symbol layer should be rendered using the selection color from the render context.

Protected Attributes inherited from QgsSymbolLayer
QPainterPath	mClipPath

QColor	mColor

QgsPropertyCollection	mDataDefinedProperties

bool	mEnabled = true
	True if layer is enabled and should be drawn.

QgsFields	mFields

QString	mId

bool	mLocked = false

std::unique_ptr< QgsPaintEffect >	mPaintEffect

int	mRenderingPass = 0

Qgis::SymbolType	mType

Qgis::SymbolLayerUserFlags	mUserFlags
	User controlled flags.

Static Protected Attributes inherited from QgsSymbolLayer
static const bool	SELECT_FILL_BORDER = false
	Whether fill styles for selected features also highlight symbol stroke.

static const bool	SELECT_FILL_STYLE = false
	Whether fill styles for selected features uses symbol layer style.

static const bool	SELECTION_IS_OPAQUE = true
	Whether styles for selected features ignore symbol alpha.

Detailed Description

A symbol layer subclass which alters rendered feature shapes through the use of QGIS expressions.

Definition at line 32 of file qgsgeometrygeneratorsymbollayer.h.

Constructor & Destructor Documentation

◆ ~QgsGeometryGeneratorSymbolLayer()

QgsGeometryGeneratorSymbolLayer::~QgsGeometryGeneratorSymbolLayer ( )

overridedefault

Member Function Documentation

◆ clone()

QgsSymbolLayer * QgsGeometryGeneratorSymbolLayer::clone ( ) const

overridevirtual

Shall be reimplemented by subclasses to create a deep copy of the instance.

Implements QgsSymbolLayer.

Definition at line 181 of file qgsgeometrygeneratorsymbollayer.cpp.

◆ color()

QColor QgsGeometryGeneratorSymbolLayer::color ( ) const

overridevirtual

Returns the "representative" color of the symbol layer.

Depending on the symbol layer type, this will have different meaning. For instance, a line symbol layer will generally return the stroke color of the layer, while a fill symbol layer will return the "fill" color instead of stroke.

Some symbol layer types will return an invalid QColor if they have no representative color associated (e.g. raster image based symbol layers).

See also: setColor(); strokeColor(); fillColor()

Reimplemented from QgsSymbolLayer.

Definition at line 138 of file qgsgeometrygeneratorsymbollayer.cpp.

◆ create()

QgsSymbolLayer * QgsGeometryGeneratorSymbolLayer::create ( const QVariantMap & properties )

static

Creates the symbol layer.

Definition at line 31 of file qgsgeometrygeneratorsymbollayer.cpp.

◆ drawPreviewIcon()

void QgsGeometryGeneratorSymbolLayer::drawPreviewIcon	(	QgsSymbolRenderContext &	context,
		QSize	size
	)

overridevirtual

Implements QgsSymbolLayer.

Definition at line 222 of file qgsgeometrygeneratorsymbollayer.cpp.

◆ geometryExpression()

QString QgsGeometryGeneratorSymbolLayer::geometryExpression ( ) const

Gets the expression to generate this geometry.

Definition at line 276 of file qgsgeometrygeneratorsymbollayer.cpp.

◆ hasDataDefinedProperties()

bool QgsGeometryGeneratorSymbolLayer::hasDataDefinedProperties ( ) const

overridevirtual

Returns true if the symbol layer (or any of its sub-symbols) contains data defined properties.

Since: QGIS 3.4.5

Reimplemented from QgsSymbolLayer.

Definition at line 313 of file qgsgeometrygeneratorsymbollayer.cpp.

◆ isCompatibleWithSymbol()

bool QgsGeometryGeneratorSymbolLayer::isCompatibleWithSymbol ( QgsSymbol * symbol ) const

overridevirtual

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.

Reimplemented from QgsSymbolLayer.

Definition at line 321 of file qgsgeometrygeneratorsymbollayer.cpp.

◆ layerType()

QString QgsGeometryGeneratorSymbolLayer::layerType ( ) const

overridevirtual

Returns a string that represents this layer type.

Used for serialization. Should match with the string used to register this symbol layer in the registry.

Implements QgsSymbolLayer.

Definition at line 67 of file qgsgeometrygeneratorsymbollayer.cpp.

◆ mapUnitScale()

QgsMapUnitScale QgsGeometryGeneratorSymbolLayer::mapUnitScale ( ) const

overridevirtual

Reimplemented from QgsSymbolLayer.

Definition at line 170 of file qgsgeometrygeneratorsymbollayer.cpp.

◆ outputUnit()

Qgis::RenderUnit QgsGeometryGeneratorSymbolLayer::outputUnit ( ) const

overridevirtual

Returns the units to use for sizes and widths within the symbol layer.

Individual symbol layer subclasses will interpret this in different ways, e.g., a marker symbol layer may use it to specify the units for the marker size, while a line symbol layer may use it to specify the units for the line width.

Returns: output unit, or QgsUnitTypes::RenderUnknownUnit if the symbol layer contains mixed units

See also: setOutputUnit()

Reimplemented from QgsSymbolLayer.

Definition at line 149 of file qgsgeometrygeneratorsymbollayer.cpp.

◆ properties()

QVariantMap QgsGeometryGeneratorSymbolLayer::properties ( ) const

overridevirtual

Should be reimplemented by subclasses to return a string map that contains the configuration information for the symbol layer.

This is used to serialize a symbol layer perstistently.

Implements QgsSymbolLayer.

Definition at line 201 of file qgsgeometrygeneratorsymbollayer.cpp.

◆ render()

void QgsGeometryGeneratorSymbolLayer::render	(	QgsSymbolRenderContext &	context,
		Qgis::GeometryType	geometryType = `Qgis::GeometryType::Unknown`,
		const QPolygonF *	points = `nullptr`,
		const QVector< QPolygonF > *	rings = `nullptr`
	)

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	The rendering context which will be used to render and to construct a geometry.
geometryType	type of original geometry being rendered by the parent symbol (since QGIS 3.22)
points	optional list of original points which are being rendered by the parent symbol (since QGIS 3.22)
rings	optional list of original rings which are being rendered by the parent symbol (since QGIS 3.22)

Definition at line 384 of file qgsgeometrygeneratorsymbollayer.cpp.

◆ setColor()

void QgsGeometryGeneratorSymbolLayer::setColor ( const QColor & color )

overridevirtual

Sets the "representative" color for the symbol layer.

Depending on the symbol layer type, this will have different meaning. For instance, a line symbol layer will generally set the stroke color of the layer, while a fill symbol layer will set the "fill" color instead of stroke.

See also: color(); setStrokeColor(); setFillColor()

Reimplemented from QgsSymbolLayer.

Definition at line 519 of file qgsgeometrygeneratorsymbollayer.cpp.

◆ setGeometryExpression()

void QgsGeometryGeneratorSymbolLayer::setGeometryExpression ( const QString & exp )

Set the expression to generate this geometry.

Definition at line 271 of file qgsgeometrygeneratorsymbollayer.cpp.

◆ setOutputUnit()

void QgsGeometryGeneratorSymbolLayer::setOutputUnit ( Qgis::RenderUnit unit )

overridevirtual

Sets the units to use for sizes and widths within the symbol layer.

Individual symbol layer subclasses will interpret this in different ways, e.g., a marker symbol layer may use it to specify the units for the marker size, while a line symbol layer may use it to specify the units for the line width.

Parameters

unit	output units

See also: outputUnit()

Reimplemented from QgsSymbolLayer.

Definition at line 160 of file qgsgeometrygeneratorsymbollayer.cpp.

◆ setSubSymbol()

bool QgsGeometryGeneratorSymbolLayer::setSubSymbol ( QgsSymbol * symbol )

overridevirtual

Sets layer's subsymbol. takes ownership of the passed symbol.

Reimplemented from QgsSymbolLayer.

Definition at line 281 of file qgsgeometrygeneratorsymbollayer.cpp.

◆ setSymbolType()

void QgsGeometryGeneratorSymbolLayer::setSymbolType ( Qgis::SymbolType symbolType )

Set the type of symbol which should be created.

Should match with the return type of the expression.

Parameters

symbolType The symbol type which shall be used below this symbol.

Definition at line 72 of file qgsgeometrygeneratorsymbollayer.cpp.

◆ setUnits()

void QgsGeometryGeneratorSymbolLayer::setUnits ( Qgis::RenderUnit units )

inline

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()

Since: QGIS 3.22

Definition at line 104 of file qgsgeometrygeneratorsymbollayer.h.

◆ startFeatureRender()

void QgsGeometryGeneratorSymbolLayer::startFeatureRender	(	const QgsFeature &	feature,
		QgsRenderContext &	context
	)

overridevirtual

Called before the layer will be rendered for a particular feature.

This is always followed by a call to stopFeatureRender() after the feature has been completely rendered (i.e. all parts have been rendered).

The default implementation does nothing.

Note: In some circumstances, startFeatureRender() and stopFeatureRender() may not be called before a symbol layer is rendered. E.g., when a symbol layer is being rendered in isolation and not as a result of rendering a feature (for instance, when rendering a legend patch or other non-feature based shape).

See also: stopFeatureRender(); startRender()

Since: QGIS 3.12

Reimplemented from QgsSymbolLayer.

Definition at line 113 of file qgsgeometrygeneratorsymbollayer.cpp.

◆ startRender()

void QgsGeometryGeneratorSymbolLayer::startRender ( QgsSymbolRenderContext & context )

overridevirtual

Called before a set of rendering operations commences on the supplied render context.

This is always followed by a call to stopRender() after all rendering operations have been completed.

Subclasses can use this method to prepare for a set of rendering operations, e.g. by pre-evaluating paths or images to render, and performing other one-time optimisations.

See also: startFeatureRender(); stopRender()

Implements QgsSymbolLayer.

Definition at line 98 of file qgsgeometrygeneratorsymbollayer.cpp.

◆ stopFeatureRender()

void QgsGeometryGeneratorSymbolLayer::stopFeatureRender	(	const QgsFeature &	feature,
		QgsRenderContext &	context
	)

overridevirtual

Called after the layer has been rendered for a particular feature.

This is always preceded by a call to startFeatureRender() just before the feature will be rendered.

The default implementation does nothing.

Note: In some circumstances, startFeatureRender() and stopFeatureRender() may not be called before a symbol layer is rendered. E.g., when a symbol layer is being rendered in isolation and not as a result of rendering a feature (for instance, when rendering a legend patch or other non-feature based shape).

See also: startFeatureRender(); stopRender()

Since: QGIS 3.12

Reimplemented from QgsSymbolLayer.

Definition at line 122 of file qgsgeometrygeneratorsymbollayer.cpp.

◆ stopRender()

void QgsGeometryGeneratorSymbolLayer::stopRender ( QgsSymbolRenderContext & context )

overridevirtual

Called after a set of rendering operations has finished on the supplied render context.

This is always preceded by a call to startRender() before all rendering operations are commenced.

Subclasses can use this method to cleanup after a set of rendering operations.

See also: startRender(); stopFeatureRender()

Implements QgsSymbolLayer.

Definition at line 107 of file qgsgeometrygeneratorsymbollayer.cpp.

◆ subSymbol()

QgsSymbol * QgsGeometryGeneratorSymbolLayer::subSymbol ( )

inlineoverridevirtual

Returns the symbol's sub symbol, if present.

Reimplemented from QgsSymbolLayer.

Definition at line 106 of file qgsgeometrygeneratorsymbollayer.h.

◆ symbolType()

Qgis::SymbolType QgsGeometryGeneratorSymbolLayer::symbolType ( ) const

inline

Access the symbol type.

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

Returns: Symbol type

Definition at line 56 of file qgsgeometrygeneratorsymbollayer.h.

◆ units()

Qgis::RenderUnit QgsGeometryGeneratorSymbolLayer::units ( ) const

inline

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()

Since: QGIS 3.22

Definition at line 93 of file qgsgeometrygeneratorsymbollayer.h.

◆ usedAttributes()

QSet< QString > QgsGeometryGeneratorSymbolLayer::usedAttributes ( const QgsRenderContext & context ) const

overridevirtual

Returns the set of attributes referenced by the layer.

This includes attributes required by any data defined properties associated with the layer.

Reimplemented from QgsSymbolLayer.

Definition at line 306 of file qgsgeometrygeneratorsymbollayer.cpp.

◆ usesMapUnits()

bool QgsGeometryGeneratorSymbolLayer::usesMapUnits ( ) const

overridevirtual

Returns true if the symbol layer has any components which use map unit based sizes.

Since: QGIS 3.18

Reimplemented from QgsSymbolLayer.

Definition at line 127 of file qgsgeometrygeneratorsymbollayer.cpp.

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

/build/qgis-3.41.0+git20241122+3440c17df1d+99sid/src/core/symbology/qgsgeometrygeneratorsymbollayer.h
/build/qgis-3.41.0+git20241122+3440c17df1d+99sid/src/core/symbology/qgsgeometrygeneratorsymbollayer.cpp

Public Member Functions

Static Public Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ ~QgsGeometryGeneratorSymbolLayer()

Member Function Documentation

◆ clone()

◆ color()

◆ create()

◆ drawPreviewIcon()

◆ geometryExpression()

◆ hasDataDefinedProperties()

◆ isCompatibleWithSymbol()

◆ layerType()

◆ mapUnitScale()

◆ outputUnit()

◆ properties()

◆ render()

◆ setColor()

◆ setGeometryExpression()

◆ setOutputUnit()

◆ setSubSymbol()

◆ setSymbolType()

◆ setUnits()

◆ startFeatureRender()

◆ startRender()

◆ stopFeatureRender()

◆ stopRender()

◆ subSymbol()

◆ symbolType()

◆ units()

◆ usedAttributes()

◆ usesMapUnits()