Rule based renderer. More...

#include <qgsrulebasedrenderer.h>

Inheritance diagram for QgsRuleBasedRenderer:

Classes
struct	FeatureToRender
	Feature for rendering by a QgsRuleBasedRenderer. More...

struct	RenderJob
	A QgsRuleBasedRenderer rendering job, consisting of a feature to be rendered with a particular symbol. More...

struct	RenderLevel
	Render level: a list of jobs to be drawn at particular level for a QgsRuleBasedRenderer. More...

class	Rule
	This class keeps data about a rules for rule-based renderer. More...

Public Types
enum	FeatureFlags { FeatIsSelected = 1 , FeatDrawMarkers = 2 }

typedef QList< QgsRuleBasedRenderer::RenderLevel >	RenderQueue
	Rendering queue: a list of rendering levels.

typedef QList< QgsRuleBasedRenderer::Rule * >	RuleList

Public Types inherited from QgsFeatureRenderer
typedef QFlags< Capability >	Capabilities

enum	Capability { SymbolLevels = 1 , MoreSymbolsPerFeature = 1 << 2 , Filter = 1 << 3 , ScaleDependent = 1 << 4 }
	Used to specify details about a renderer. More...

enum class	Property : int { HeatmapRadius , HeatmapMaximum }
	Data definable properties for renderers. More...

Public Member Functions
	QgsRuleBasedRenderer (QgsRuleBasedRenderer::Rule *root)
	Constructs the renderer from given tree of rules (takes ownership)

	QgsRuleBasedRenderer (QgsSymbol *defaultSymbol)
	Constructor for convenience. Creates a root rule and adds a default rule with symbol (takes ownership)

	~QgsRuleBasedRenderer () override

bool	accept (QgsStyleEntityVisitorInterface *visitor) const override
	Accepts the specified symbology visitor, causing it to visit all symbols associated with the renderer.

bool	canSkipRender () override
	Returns `true` if the renderer can be entirely skipped, i.e.

QgsFeatureRenderer::Capabilities	capabilities () override
	Returns details about internals of this renderer.

void	checkLegendSymbolItem (const QString &key, bool state=true) override
	Sets whether the legend symbology item with the specified ley should be checked.

QgsRuleBasedRenderer *	clone () const override
	Create a deep copy of this renderer.

QString	dump () const override
	Returns debug information about this renderer.

QString	filter (const QgsFields &fields=QgsFields()) override
	If a renderer does not require all the features this method may be overridden and return an expression used as where clause.

bool	filterNeedsGeometry () const override
	Returns `true` if this renderer requires the geometry to apply the filter.

Qgis::FeatureRendererFlags	flags () const override
	Returns flags associated with the renderer.

QSet< QString >	legendKeysForFeature (const QgsFeature &feature, QgsRenderContext &context) const override
	Returns legend keys matching a specified feature.

QString	legendKeyToExpression (const QString &key, QgsVectorLayer *layer, bool &ok) const override
	Attempts to convert the specified legend rule key to a QGIS expression matching the features displayed using that key.

bool	legendSymbolItemChecked (const QString &key) override
	Returns `true` if the legend symbology item with the specified key is checked.

QgsLegendSymbolList	legendSymbolItems () const override
	Returns a list of symbology items for the legend.

bool	legendSymbolItemsCheckable () const override
	Returns `true` if symbology items in legend are checkable.

QgsSymbolList	originalSymbolsForFeature (const QgsFeature &feature, QgsRenderContext &context) const override
	Equivalent of originalSymbolsForFeature() call extended to support renderers that may use more symbols per feature - similar to symbolsForFeature()

bool	renderFeature (const QgsFeature &feature, QgsRenderContext &context, int layer=-1, bool selected=false, bool drawVertexMarker=false) override
	Render a feature using this renderer in the given context.

QgsRuleBasedRenderer::Rule *	rootRule ()

QDomElement	save (QDomDocument &doc, const QgsReadWriteContext &context) override
	Stores renderer properties to an XML element.

void	setLegendSymbolItem (const QString &key, QgsSymbol *symbol) override
	Sets the symbol to be used for a legend symbol item.

void	startRender (QgsRenderContext &context, const QgsFields &fields) override
	Must be called when a new render cycle is started.

void	stopRender (QgsRenderContext &context) override
	Must be called when a render cycle has finished, to allow the renderer to clean up.

QgsSymbol *	symbolForFeature (const QgsFeature &feature, QgsRenderContext &context) const override
	Returns symbol for current feature. Should not be used individually: there could be more symbols for a feature.

QgsSymbolList	symbols (QgsRenderContext &context) const override
	Returns list of symbols used by the renderer.

QgsSymbolList	symbolsForFeature (const QgsFeature &feature, QgsRenderContext &context) const override
	Returns list of symbols used for rendering the feature.

void	toSld (QDomDocument &doc, QDomElement &element, const QVariantMap &props=QVariantMap()) const override
	used from subclasses to create SLD Rule elements following SLD v1.1 specs

QSet< QString >	usedAttributes (const QgsRenderContext &context) const override
	Returns a list of attributes required by this renderer.

bool	willRenderFeature (const QgsFeature &feature, QgsRenderContext &context) const override
	Returns whether the renderer will render a feature or not.

Public Member Functions inherited from QgsFeatureRenderer
virtual	~QgsFeatureRenderer ()

void	copyRendererData (QgsFeatureRenderer *destRenderer) const
	Clones generic renderer data to another renderer.

virtual QList< QgsLayerTreeModelLegendNode * >	createLegendNodes (QgsLayerTreeLayer *nodeLayer) const
	Returns a list of legend nodes to be used for the legend for the renderer.

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

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

virtual const QgsFeatureRenderer *	embeddedRenderer () const
	Returns the current embedded renderer (subrenderer) for this feature renderer.

bool	forceRasterRender () const
	Returns whether the renderer must render as a raster.

virtual QString	legendClassificationAttribute () const
	If supported by the renderer, return classification attribute for the use in legend.

QSet< QString >	legendKeys () const
	Returns the set of all legend keys used by the renderer.

double	maximumExtentBuffer (QgsRenderContext &context) const
	Returns the maximum extent buffer found in this renderer's symbols.

virtual void	modifyRequestExtent (QgsRectangle &extent, QgsRenderContext &context)
	Allows for a renderer to modify the extent of a feature request prior to rendering.

QgsFeatureRequest::OrderBy	orderBy () const
	Gets the order in which features shall be processed by this renderer.

bool	orderByEnabled () const
	Returns whether custom ordering will be applied before features are processed by this renderer.

virtual QgsSymbol *	originalSymbolForFeature (const QgsFeature &feature, QgsRenderContext &context) const
	Returns symbol for feature.

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

double	referenceScale () const
	Returns the symbology reference scale.

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

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

virtual void	setEmbeddedRenderer (QgsFeatureRenderer *subRenderer)
	Sets an embedded renderer (subrenderer) for this feature renderer.

void	setForceRasterRender (bool forceRaster)
	Sets whether the renderer should be rendered to a raster destination.

void	setOrderBy (const QgsFeatureRequest::OrderBy &orderBy)
	Define the order in which features shall be processed by this renderer.

void	setOrderByEnabled (bool enabled)
	Sets whether custom ordering should be applied before features are processed by this renderer.

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

void	setReferenceScale (double scale)
	Sets the symbology reference scale.

void	setUsingSymbolLevels (bool usingSymbolLevels)

void	setVertexMarkerAppearance (Qgis::VertexMarkerType type, double size)
	Sets type and size of editing vertex markers for subsequent rendering.

QString	type () const

virtual bool	usesEmbeddedSymbols () const
	Returns `true` if the renderer uses embedded symbols for features.

bool	usingSymbolLevels () const

virtual QDomElement	writeSld (QDomDocument &doc, const QString &styleName, const QVariantMap &props=QVariantMap()) const
	create the SLD UserStyle element following the SLD v1.1 specs with the given name

Static Public Member Functions
static QgsRuleBasedRenderer *	convertFromRenderer (const QgsFeatureRenderer renderer, QgsVectorLayer layer=nullptr)
	Creates a new QgsRuleBasedRenderer from an existing renderer.

static void	convertToDataDefinedSymbology (QgsSymbol *symbol, const QString &sizeScaleField, const QString &rotationField=QString())
	helper function to convert the size scale and rotation fields present in some other renderers to data defined symbology

static QgsFeatureRenderer *	create (QDomElement &element, const QgsReadWriteContext &context)
	Creates a new rule-based renderer instance from XML.

static QgsFeatureRenderer *	createFromSld (QDomElement &element, Qgis::GeometryType geomType)
	Creates a new rule based renderer from an SLD XML element.

static void	refineRuleCategories (QgsRuleBasedRenderer::Rule initialRule, QgsCategorizedSymbolRenderer r)
	take a rule and create a list of new rules based on the categories from categorized symbol renderer

static void	refineRuleRanges (QgsRuleBasedRenderer::Rule initialRule, QgsGraduatedSymbolRenderer r)
	take a rule and create a list of new rules based on the ranges from graduated symbol renderer

static void	refineRuleScales (QgsRuleBasedRenderer::Rule *initialRule, QList< int > scales)
	take a rule and create a list of new rules with intervals of scales given by the passed scale denominators

Static Public Member Functions inherited from QgsFeatureRenderer
static QgsFeatureRenderer *	defaultRenderer (Qgis::GeometryType geomType)
	Returns a new renderer - used by default in vector layers.

static QgsFeatureRenderer *	load (QDomElement &symbologyElem, const QgsReadWriteContext &context)
	create a renderer from XML element

static QgsFeatureRenderer *	loadSld (const QDomNode &node, Qgis::GeometryType geomType, QString &errorMessage)
	Create a new renderer according to the information contained in the UserStyle element of a SLD style document.

static const QgsPropertiesDefinition &	propertyDefinitions ()
	Returns the symbol property definitions.

Protected Attributes
QList< FeatureToRender >	mCurrentFeatures

QString	mFilter

RenderQueue	mRenderQueue

Rule *	mRootRule = nullptr
	the root node with hierarchical list of rules

Protected Attributes inherited from QgsFeatureRenderer
double	mCurrentVertexMarkerSize = 2
	The current size of editing marker.

Qgis::VertexMarkerType	mCurrentVertexMarkerType = Qgis::VertexMarkerType::Cross
	The current type of editing marker.

bool	mForceRaster = false

QgsFeatureRequest::OrderBy	mOrderBy

bool	mOrderByEnabled = false

QgsPaintEffect *	mPaintEffect = nullptr

double	mReferenceScale = -1.0

QString	mType

bool	mUsingSymbolLevels = false

Additional Inherited Members
Protected Member Functions inherited from QgsFeatureRenderer
	QgsFeatureRenderer (const QString &type)

void	renderFeatureWithSymbol (const QgsFeature &feature, QgsSymbol *symbol, QgsRenderContext &context, int layer, bool selected, bool drawVertexMarker)
	Render the feature with the symbol using context.

void	renderVertexMarker (QPointF pt, QgsRenderContext &context)
	render editing vertex marker at specified point

void	renderVertexMarkerPolygon (QPolygonF &pts, QList< QPolygonF > *rings, QgsRenderContext &context)
	render editing vertex marker for a polygon

void	renderVertexMarkerPolyline (QPolygonF &pts, QgsRenderContext &context)
	render editing vertex marker for a polyline

void	saveRendererData (QDomDocument &doc, QDomElement &element, const QgsReadWriteContext &context)
	Saves generic renderer data into the specified element.

Static Protected Member Functions inherited from QgsFeatureRenderer
static QPointF	_getPoint (QgsRenderContext &context, const QgsPoint &point)
	Creates a point in screen coordinates from a wkb string in map coordinates.

static void	convertSymbolRotation (QgsSymbol *symbol, const QString &field)

static void	convertSymbolSizeScale (QgsSymbol *symbol, Qgis::ScaleMethod method, const QString &field)

Detailed Description

Rule based renderer.

When drawing a vector layer with rule-based renderer, it goes through the rules and draws features with symbols from rules that match.

Definition at line 40 of file qgsrulebasedrenderer.h.

Member Typedef Documentation

◆ RenderQueue

typedef QList<QgsRuleBasedRenderer::RenderLevel> QgsRuleBasedRenderer::RenderQueue

Rendering queue: a list of rendering levels.

Definition at line 134 of file qgsrulebasedrenderer.h.

◆ RuleList

typedef QList<QgsRuleBasedRenderer::Rule *> QgsRuleBasedRenderer::RuleList

Definition at line 137 of file qgsrulebasedrenderer.h.

Member Enumeration Documentation

◆ FeatureFlags

enum QgsRuleBasedRenderer::FeatureFlags

Enumerator
FeatIsSelected
FeatDrawMarkers

Definition at line 45 of file qgsrulebasedrenderer.h.

Constructor & Destructor Documentation

◆ QgsRuleBasedRenderer() [1/2]

QgsRuleBasedRenderer::QgsRuleBasedRenderer ( QgsRuleBasedRenderer::Rule * root )

Constructs the renderer from given tree of rules (takes ownership)

Definition at line 960 of file qgsrulebasedrenderer.cpp.

◆ QgsRuleBasedRenderer() [2/2]

QgsRuleBasedRenderer::QgsRuleBasedRenderer ( QgsSymbol * defaultSymbol )

Constructor for convenience. Creates a root rule and adds a default rule with symbol (takes ownership)

Definition at line 966 of file qgsrulebasedrenderer.cpp.

◆ ~QgsRuleBasedRenderer()

QgsRuleBasedRenderer::~QgsRuleBasedRenderer ( )

override

Definition at line 973 of file qgsrulebasedrenderer.cpp.

Member Function Documentation

◆ accept()

bool QgsRuleBasedRenderer::accept ( QgsStyleEntityVisitorInterface * visitor ) const

overridevirtual

Accepts the specified symbology visitor, causing it to visit all symbols associated with the renderer.

Returns true if the visitor should continue visiting other objects, or false if visiting should be canceled.

Since: QGIS 3.10

Reimplemented from QgsFeatureRenderer.

Definition at line 1454 of file qgsrulebasedrenderer.cpp.

◆ canSkipRender()

bool QgsRuleBasedRenderer::canSkipRender ( )

overridevirtual

Returns true if the renderer can be entirely skipped, i.e.

if it is known in advance that no features will be rendered.

Warning: Must be called between startRender() and stopRender() calls.

Since: QGIS 3.30

Reimplemented from QgsFeatureRenderer.

Definition at line 1053 of file qgsrulebasedrenderer.cpp.

◆ capabilities()

QgsFeatureRenderer::Capabilities QgsRuleBasedRenderer::capabilities ( )

inlineoverridevirtual

Returns details about internals of this renderer.

E.g. if you only want to deal with visible features:

if not renderer.capabilities().testFlag(QgsFeatureRenderer.Filter) or renderer.willRenderFeature(feature, context):
    deal_with_my_feature()
else:
    skip_the_curren_feature()

Reimplemented from QgsFeatureRenderer.

Definition at line 547 of file qgsrulebasedrenderer.h.

◆ checkLegendSymbolItem()

void QgsRuleBasedRenderer::checkLegendSymbolItem	(	const QString &	key,
		bool	state = `true`
	)

overridevirtual

Sets whether the legend symbology item with the specified ley should be checked.

See also: legendSymbolItemChecked(); legendKeys()

Reimplemented from QgsFeatureRenderer.

Definition at line 1181 of file qgsrulebasedrenderer.cpp.

◆ clone()

QgsRuleBasedRenderer * QgsRuleBasedRenderer::clone ( ) const

overridevirtual

Create a deep copy of this renderer.

Should be implemented by all subclasses and generate a proper subclass.

Returns: A copy of this renderer

Implements QgsFeatureRenderer.

Definition at line 1121 of file qgsrulebasedrenderer.cpp.

◆ convertFromRenderer()

QgsRuleBasedRenderer * QgsRuleBasedRenderer::convertFromRenderer	(	const QgsFeatureRenderer *	renderer,
		QgsVectorLayer *	layer = `nullptr`
	)

static

Creates a new QgsRuleBasedRenderer from an existing renderer.

Since QGIS 3.20, the optional layer parameter is required for conversions of some renderer types.

Returns: a new renderer if the conversion was possible, otherwise nullptr.

Definition at line 1459 of file qgsrulebasedrenderer.cpp.

◆ convertToDataDefinedSymbology()

void QgsRuleBasedRenderer::convertToDataDefinedSymbology	(	QgsSymbol *	symbol,
		const QString &	sizeScaleField,
		const QString &	rotationField = `QString()`
	)

static

helper function to convert the size scale and rotation fields present in some other renderers to data defined symbology

Definition at line 1691 of file qgsrulebasedrenderer.cpp.

◆ create()

QgsFeatureRenderer * QgsRuleBasedRenderer::create	(	QDomElement &	element,
		const QgsReadWriteContext &	context
	)

static

Creates a new rule-based renderer instance from XML.

Definition at line 1284 of file qgsrulebasedrenderer.cpp.

◆ createFromSld()

QgsFeatureRenderer * QgsRuleBasedRenderer::createFromSld	(	QDomElement &	element,
		Qgis::GeometryType	geomType
	)

static

Creates a new rule based renderer from an SLD XML element.

Definition at line 1307 of file qgsrulebasedrenderer.cpp.

◆ dump()

QString QgsRuleBasedRenderer::dump ( ) const

overridevirtual

Returns debug information about this renderer.

Reimplemented from QgsFeatureRenderer.

Definition at line 1427 of file qgsrulebasedrenderer.cpp.

◆ filter()

QString QgsRuleBasedRenderer::filter ( const QgsFields & fields = QgsFields() )

overridevirtual

If a renderer does not require all the features this method may be overridden and return an expression used as where clause.

This will be called once after startRender() and before the first call to renderFeature(). By default this returns a null string and all features will be requested. You do not need to specify the extent in here, this is taken care of separately and will be combined with a filter returned from this method.

Returns: An expression used as where clause

Reimplemented from QgsFeatureRenderer.

Definition at line 1106 of file qgsrulebasedrenderer.cpp.

◆ filterNeedsGeometry()

bool QgsRuleBasedRenderer::filterNeedsGeometry ( ) const

overridevirtual

Returns true if this renderer requires the geometry to apply the filter.

Reimplemented from QgsFeatureRenderer.

Definition at line 1116 of file qgsrulebasedrenderer.cpp.

◆ flags()

Qgis::FeatureRendererFlags QgsRuleBasedRenderer::flags ( ) const

overridevirtual

Returns flags associated with the renderer.

Since: QGIS 3.40

Reimplemented from QgsFeatureRenderer.

Definition at line 985 of file qgsrulebasedrenderer.cpp.

◆ legendKeysForFeature()

QSet< QString > QgsRuleBasedRenderer::legendKeysForFeature	(	const QgsFeature &	feature,
		QgsRenderContext &	context
	)		const

overridevirtual

Returns legend keys matching a specified feature.

Reimplemented from QgsFeatureRenderer.

Definition at line 1449 of file qgsrulebasedrenderer.cpp.

◆ legendKeyToExpression()

QString QgsRuleBasedRenderer::legendKeyToExpression	(	const QString &	key,
		QgsVectorLayer *	layer,
		bool &	ok
	)		const

overridevirtual

Attempts to convert the specified legend rule key to a QGIS expression matching the features displayed using that key.

Parameters

key	legend key
layer	associated vector layer
ok	will be set to `true` if legend key was successfully converted to a filter expression

Returns: QGIS expression string for matching features with the specified key

See also: legendKeys()

Since: QGIS 3.26

Reimplemented from QgsFeatureRenderer.

Definition at line 1188 of file qgsrulebasedrenderer.cpp.

◆ legendSymbolItemChecked()

bool QgsRuleBasedRenderer::legendSymbolItemChecked ( const QString & key )

overridevirtual

Returns true if the legend symbology item with the specified key is checked.

See also: checkLegendSymbolItem(); legendKeys()

Reimplemented from QgsFeatureRenderer.

Definition at line 1175 of file qgsrulebasedrenderer.cpp.

◆ legendSymbolItems()

QgsLegendSymbolList QgsRuleBasedRenderer::legendSymbolItems ( ) const

overridevirtual

Returns a list of symbology items for the legend.

See also: createLegendNodes(); legendKeys()

Reimplemented from QgsFeatureRenderer.

Definition at line 1278 of file qgsrulebasedrenderer.cpp.

◆ legendSymbolItemsCheckable()

bool QgsRuleBasedRenderer::legendSymbolItemsCheckable ( ) const

overridevirtual

Returns true if symbology items in legend are checkable.

Reimplemented from QgsFeatureRenderer.

Definition at line 1170 of file qgsrulebasedrenderer.cpp.

◆ originalSymbolsForFeature()

QgsSymbolList QgsRuleBasedRenderer::originalSymbolsForFeature	(	const QgsFeature &	feature,
		QgsRenderContext &	context
	)		const

overridevirtual

Equivalent of originalSymbolsForFeature() call extended to support renderers that may use more symbols per feature - similar to symbolsForFeature()

Reimplemented from QgsFeatureRenderer.

Definition at line 1444 of file qgsrulebasedrenderer.cpp.

◆ refineRuleCategories()

void QgsRuleBasedRenderer::refineRuleCategories	(	QgsRuleBasedRenderer::Rule *	initialRule,
		QgsCategorizedSymbolRenderer *	r
	)

static

take a rule and create a list of new rules based on the categories from categorized symbol renderer

Definition at line 1341 of file qgsrulebasedrenderer.cpp.

◆ refineRuleRanges()

void QgsRuleBasedRenderer::refineRuleRanges	(	QgsRuleBasedRenderer::Rule *	initialRule,
		QgsGraduatedSymbolRenderer *	r
	)

static

take a rule and create a list of new rules based on the ranges from graduated symbol renderer

Definition at line 1375 of file qgsrulebasedrenderer.cpp.

◆ refineRuleScales()

void QgsRuleBasedRenderer::refineRuleScales	(	QgsRuleBasedRenderer::Rule *	initialRule,
		QList< int >	scales
	)

static

take a rule and create a list of new rules with intervals of scales given by the passed scale denominators

Definition at line 1407 of file qgsrulebasedrenderer.cpp.

◆ renderFeature()

bool QgsRuleBasedRenderer::renderFeature	(	const QgsFeature &	feature,
		QgsRenderContext &	context,
		int	layer = `-1`,
		bool	selected = `false`,
		bool	drawVertexMarker = `false`
	)

overridevirtual

Render a feature using this renderer in the given context.

Must be called between startRender() and stopRender() calls. Default implementation renders a symbol as determined by symbolForFeature() call. Returns true if the feature has been returned (this is used for example to determine whether the feature may be labelled).

If layer is not -1, the renderer should draw only a particular layer from symbols (in order to support symbol level rendering).

See also: startRender(); stopRender()

Reimplemented from QgsFeatureRenderer.

Definition at line 1011 of file qgsrulebasedrenderer.cpp.

◆ rootRule()

QgsRuleBasedRenderer::Rule * QgsRuleBasedRenderer::rootRule ( )

inline

Definition at line 552 of file qgsrulebasedrenderer.h.

◆ save()

QDomElement QgsRuleBasedRenderer::save	(	QDomDocument &	doc,
		const QgsReadWriteContext &	context
	)

overridevirtual

Stores renderer properties to an XML element.

Subclasses which override this method should call saveRendererData() as part of their implementation in order to store all common base class properties in the returned DOM element.

Reimplemented from QgsFeatureRenderer.

Definition at line 1151 of file qgsrulebasedrenderer.cpp.

◆ setLegendSymbolItem()

void QgsRuleBasedRenderer::setLegendSymbolItem	(	const QString &	key,
		QgsSymbol *	symbol
	)

overridevirtual

Sets the symbol to be used for a legend symbol item.

Parameters

key	rule key for legend symbol
symbol	new symbol for legend item. Ownership is transferred to renderer.

See also: legendKeys()

Reimplemented from QgsFeatureRenderer.

Definition at line 1269 of file qgsrulebasedrenderer.cpp.

◆ startRender()

void QgsRuleBasedRenderer::startRender	(	QgsRenderContext &	context,
		const QgsFields &	fields
	)

overridevirtual

Must be called when a new render cycle is started.

A call to startRender() must always be followed by a corresponding call to stopRender() after all features have been rendered.

Parameters

context	Additional information passed to the renderer about the job which will be rendered
fields	The fields available for rendering

See also: stopRender()

Warning: This method is not thread safe. Before calling startRender() in a non-main thread, the renderer should instead be cloned and startRender()/stopRender() called on the clone.

Reimplemented from QgsFeatureRenderer.

Definition at line 1027 of file qgsrulebasedrenderer.cpp.

◆ stopRender()

void QgsRuleBasedRenderer::stopRender ( QgsRenderContext & context )

overridevirtual

Must be called when a render cycle has finished, to allow the renderer to clean up.

Calls to stopRender() must always be preceded by a call to startRender().

Warning: This method is not thread safe. Before calling startRender() in a non-main thread, the renderer should instead be cloned and startRender()/stopRender() called on the clone.

See also: startRender()

Reimplemented from QgsFeatureRenderer.

Definition at line 1058 of file qgsrulebasedrenderer.cpp.

◆ symbolForFeature()

QgsSymbol * QgsRuleBasedRenderer::symbolForFeature	(	const QgsFeature &	feature,
		QgsRenderContext &	context
	)		const

overridevirtual

Returns symbol for current feature. Should not be used individually: there could be more symbols for a feature.

Implements QgsFeatureRenderer.

Definition at line 979 of file qgsrulebasedrenderer.cpp.

◆ symbols()

QgsSymbolList QgsRuleBasedRenderer::symbols ( QgsRenderContext & context ) const

overridevirtual

Returns list of symbols used by the renderer.

Parameters

context render context

Reimplemented from QgsFeatureRenderer.

Definition at line 1146 of file qgsrulebasedrenderer.cpp.

◆ symbolsForFeature()

QgsSymbolList QgsRuleBasedRenderer::symbolsForFeature	(	const QgsFeature &	feature,
		QgsRenderContext &	context
	)		const

overridevirtual

Returns list of symbols used for rendering the feature.

For renderers that do not support MoreSymbolsPerFeature it is more efficient to use symbolForFeature()

Reimplemented from QgsFeatureRenderer.

Definition at line 1439 of file qgsrulebasedrenderer.cpp.

◆ toSld()

void QgsRuleBasedRenderer::toSld	(	QDomDocument &	doc,
		QDomElement &	element,
		const QVariantMap &	props = `QVariantMap()`
	)		const

overridevirtual

used from subclasses to create SLD Rule elements following SLD v1.1 specs

Reimplemented from QgsFeatureRenderer.

Definition at line 1140 of file qgsrulebasedrenderer.cpp.

◆ usedAttributes()

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

overridevirtual

Returns a list of attributes required by this renderer.

Attributes not listed in here may not have been requested from the provider at rendering time.

Returns: A set of attributes

Implements QgsFeatureRenderer.

Definition at line 1111 of file qgsrulebasedrenderer.cpp.

◆ willRenderFeature()

bool QgsRuleBasedRenderer::willRenderFeature	(	const QgsFeature &	feature,
		QgsRenderContext &	context
	)		const

overridevirtual

Returns whether the renderer will render a feature or not.

Must be called between startRender() and stopRender() calls. Default implementation uses symbolForFeature().

Reimplemented from QgsFeatureRenderer.

Definition at line 1434 of file qgsrulebasedrenderer.cpp.

Member Data Documentation

◆ mCurrentFeatures

QList<FeatureToRender> QgsRuleBasedRenderer::mCurrentFeatures

protected

Definition at line 581 of file qgsrulebasedrenderer.h.

◆ mFilter

QString QgsRuleBasedRenderer::mFilter

protected

Definition at line 583 of file qgsrulebasedrenderer.h.

◆ mRenderQueue

RenderQueue QgsRuleBasedRenderer::mRenderQueue

protected

Definition at line 580 of file qgsrulebasedrenderer.h.

◆ mRootRule

Rule* QgsRuleBasedRenderer::mRootRule = nullptr

protected

the root node with hierarchical list of rules

Definition at line 577 of file qgsrulebasedrenderer.h.

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

/build/qgis-3.41.0+git20241225+af5edcb665c+99sid/src/core/symbology/qgsrulebasedrenderer.h
/build/qgis-3.41.0+git20241225+af5edcb665c+99sid/src/core/symbology/qgsrulebasedrenderer.cpp

Classes

Public Types

Public Member Functions

Static Public Member Functions

Protected Attributes

Additional Inherited Members

Detailed Description

Member Typedef Documentation

◆ RenderQueue

◆ RuleList

Member Enumeration Documentation

◆ FeatureFlags

Constructor & Destructor Documentation

◆ QgsRuleBasedRenderer() [1/2]

◆ QgsRuleBasedRenderer() [2/2]

◆ ~QgsRuleBasedRenderer()

Member Function Documentation

◆ accept()

◆ canSkipRender()

◆ capabilities()

◆ checkLegendSymbolItem()

◆ clone()

◆ convertFromRenderer()

◆ convertToDataDefinedSymbology()

◆ create()

◆ createFromSld()

◆ dump()

◆ filter()

◆ filterNeedsGeometry()

◆ flags()

◆ legendKeysForFeature()

◆ legendKeyToExpression()

◆ legendSymbolItemChecked()

◆ legendSymbolItems()

◆ legendSymbolItemsCheckable()

◆ originalSymbolsForFeature()

◆ refineRuleCategories()

◆ refineRuleRanges()

◆ refineRuleScales()

◆ renderFeature()

◆ rootRule()

◆ save()

◆ setLegendSymbolItem()

◆ startRender()

◆ stopRender()

◆ symbolForFeature()

◆ symbols()

◆ symbolsForFeature()

◆ toSld()

◆ usedAttributes()

◆ willRenderFeature()

Member Data Documentation

◆ mCurrentFeatures

◆ mFilter

◆ mRenderQueue

◆ mRootRule