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

#include <qgsrulebasedrenderer.h>

Inheritance diagram for QgsRuleBasedRenderer:

[legend]

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. More...

typedef QList< QgsRuleBasedRenderer::Rule * >	RuleList

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

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

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

	~QgsRuleBasedRenderer () override

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

void	checkLegendSymbolItem (const QString &key, bool state=true) override
	item in symbology was checked More...

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

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

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. More...

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

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

bool	legendSymbolItemChecked (const QString &key) override
	items of symbology items in legend is checked More...

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

bool	legendSymbolItemsCheckable () const override
	items of symbology items in legend should be checkable More...

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() More...

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

QgsRuleBasedRenderer::Rule *	rootRule ()

QDomElement	save (QDomDocument &doc, const QgsReadWriteContext &context) override
	store renderer info to XML element More...

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

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

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

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. More...

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

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

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

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

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

Public Member Functions inherited from QgsFeatureRenderer
virtual	~QgsFeatureRenderer ()

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

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

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

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

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

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

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

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

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

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

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

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

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

void	setUsingSymbolLevels (bool usingSymbolLevels)

void	setVertexMarkerAppearance (int type, double size)
	Sets type and size of editing vertex markers for subsequent rendering. More...

QString	type () const

bool	usingSymbolLevels () const

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

Static Public Member Functions
static QgsRuleBasedRenderer *	convertFromRenderer (const QgsFeatureRenderer *renderer)
	creates a QgsRuleBasedRenderer from an existing renderer. More...

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 More...

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

static QgsFeatureRenderer *	createFromSld (QDomElement &element, QgsWkbTypes::GeometryType geomType)

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 More...

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 More...

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 More...

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

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

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

Protected Attributes
QList< FeatureToRender >	mCurrentFeatures

QString	mFilter

RenderQueue	mRenderQueue

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

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

int	mCurrentVertexMarkerType
	The current type of editing marker. More...

bool	mForceRaster

QgsFeatureRequest::OrderBy	mOrderBy

bool	mOrderByEnabled

QgsPaintEffect *	mPaintEffect = nullptr

QString	mType

bool	mUsingSymbolLevels

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

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

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

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

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

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

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. More...

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

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

Detailed Description

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 37 of file qgsrulebasedrenderer.h.

Member Typedef Documentation

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

Rendering queue: a list of rendering levels.

Definition at line 117 of file qgsrulebasedrenderer.h.

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

Definition at line 119 of file qgsrulebasedrenderer.h.

Member Enumeration Documentation

enum QgsRuleBasedRenderer::FeatureFlags

Enumerator
FeatIsSelected
FeatDrawMarkers

Definition at line 42 of file qgsrulebasedrenderer.h.

Constructor & Destructor Documentation

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

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

Definition at line 857 of file qgsrulebasedrenderer.cpp.

QgsRuleBasedRenderer::QgsRuleBasedRenderer ( QgsSymbol * defaultSymbol )

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

Definition at line 863 of file qgsrulebasedrenderer.cpp.

QgsRuleBasedRenderer::~QgsRuleBasedRenderer ( )

override

Definition at line 870 of file qgsrulebasedrenderer.cpp.

Member Function Documentation

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 511 of file qgsrulebasedrenderer.h.

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

overridevirtual

item in symbology was checked

Since: QGIS 2.5

Reimplemented from QgsFeatureRenderer.

Definition at line 1057 of file qgsrulebasedrenderer.cpp.

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 985 of file qgsrulebasedrenderer.cpp.

QgsRuleBasedRenderer * QgsRuleBasedRenderer::convertFromRenderer ( const QgsFeatureRenderer * renderer )

static

creates a QgsRuleBasedRenderer from an existing renderer.

Returns: a new renderer if the conversion was possible, otherwise 0.

Since: QGIS 2.5

Definition at line 1243 of file qgsrulebasedrenderer.cpp.

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 1397 of file qgsrulebasedrenderer.cpp.

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

static

Creates a new rule-based renderer instance from XML.

Definition at line 1079 of file qgsrulebasedrenderer.cpp.

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

static

Definition at line 1102 of file qgsrulebasedrenderer.cpp.

QString QgsRuleBasedRenderer::dump ( ) const

overridevirtual

Returns debug information about this renderer.

Reimplemented from QgsFeatureRenderer.

Definition at line 1216 of file qgsrulebasedrenderer.cpp.

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 970 of file qgsrulebasedrenderer.cpp.

bool QgsRuleBasedRenderer::filterNeedsGeometry ( ) const

overridevirtual

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

Reimplemented from QgsFeatureRenderer.

Definition at line 980 of file qgsrulebasedrenderer.cpp.

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

overridevirtual

Returns legend keys matching a specified feature.

Since: QGIS 2.14

Reimplemented from QgsFeatureRenderer.

Definition at line 1238 of file qgsrulebasedrenderer.cpp.

bool QgsRuleBasedRenderer::legendSymbolItemChecked ( const QString & key )

overridevirtual

items of symbology items in legend is checked

Since: QGIS 2.5

Reimplemented from QgsFeatureRenderer.

Definition at line 1051 of file qgsrulebasedrenderer.cpp.

QgsLegendSymbolList QgsRuleBasedRenderer::legendSymbolItems ( ) const

overridevirtual

Returns a list of symbology items for the legend.

Since: QGIS 2.6

Reimplemented from QgsFeatureRenderer.

Definition at line 1073 of file qgsrulebasedrenderer.cpp.

bool QgsRuleBasedRenderer::legendSymbolItemsCheckable ( ) const

overridevirtual

items of symbology items in legend should be checkable

Since: QGIS 2.5

Reimplemented from QgsFeatureRenderer.

Definition at line 1046 of file qgsrulebasedrenderer.cpp.

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()

Since: QGIS 2.12

Reimplemented from QgsFeatureRenderer.

Definition at line 1233 of file qgsrulebasedrenderer.cpp.

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 1136 of file qgsrulebasedrenderer.cpp.

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 1166 of file qgsrulebasedrenderer.cpp.

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 1197 of file qgsrulebasedrenderer.cpp.

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 particula layer from symbols (in order to support symbol level rendering).

See also: startRender(); stopRender()

Reimplemented from QgsFeatureRenderer.

Definition at line 882 of file qgsrulebasedrenderer.cpp.

QgsRuleBasedRenderer::Rule* QgsRuleBasedRenderer::rootRule ( )

inline

Definition at line 515 of file qgsrulebasedrenderer.h.

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

overridevirtual

store renderer info to XML element

Reimplemented from QgsFeatureRenderer.

Definition at line 1016 of file qgsrulebasedrenderer.cpp.

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.

Since: QGIS 2.14

Reimplemented from QgsFeatureRenderer.

Definition at line 1064 of file qgsrulebasedrenderer.cpp.

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 898 of file qgsrulebasedrenderer.cpp.

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 923 of file qgsrulebasedrenderer.cpp.

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 876 of file qgsrulebasedrenderer.cpp.

QgsSymbolList QgsRuleBasedRenderer::symbols ( QgsRenderContext & context ) const

overridevirtual

Returns list of symbols used by the renderer.

Parameters

context render context

Since: QGIS 2.12

Reimplemented from QgsFeatureRenderer.

Definition at line 1011 of file qgsrulebasedrenderer.cpp.

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()

Since: QGIS 2.12

Reimplemented from QgsFeatureRenderer.

Definition at line 1228 of file qgsrulebasedrenderer.cpp.

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

overridevirtual

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

Reimplemented from QgsFeatureRenderer.

Definition at line 1005 of file qgsrulebasedrenderer.cpp.

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 975 of file qgsrulebasedrenderer.cpp.

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().

Since: QGIS 2.12

Reimplemented from QgsFeatureRenderer.

Definition at line 1223 of file qgsrulebasedrenderer.cpp.

Member Data Documentation

QList<FeatureToRender> QgsRuleBasedRenderer::mCurrentFeatures

protected

Definition at line 542 of file qgsrulebasedrenderer.h.

QString QgsRuleBasedRenderer::mFilter

protected

Definition at line 544 of file qgsrulebasedrenderer.h.

RenderQueue QgsRuleBasedRenderer::mRenderQueue

protected

Definition at line 541 of file qgsrulebasedrenderer.h.

Rule* QgsRuleBasedRenderer::mRootRule = nullptr

protected

the root node with hierarchical list of rules

Definition at line 538 of file qgsrulebasedrenderer.h.

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

/build/qgis-3.4.15+24xenial/src/core/symbology/qgsrulebasedrenderer.h
/build/qgis-3.4.15+24xenial/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

Member Enumeration Documentation

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation