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

#include <qgsrulebasedrenderer.h>

Public Types
enum	RenderResult { Filtered = 0 , Inactive , Rendered }
	The result of rendering a rule. More...

Public Member Functions
	Rule (const Rule &rh)=delete
	Rules cannot be copied. More...

	Rule (QgsSymbol *symbol, int maximumScale=0, int minimumScale=0, const QString &filterExp=QString(), const QString &label=QString(), const QString &description=QString(), bool elseRule=false)
	Constructor takes ownership of the symbol. More...

	~Rule ()

bool	accept (QgsStyleEntityVisitorInterface *visitor) const
	Accepts the specified symbology visitor, causing it to visit all child rules associated with the rule. More...

bool	active () const
	Returns if this rule is active. More...

void	appendChild (QgsRuleBasedRenderer::Rule *rule)
	add child rule, take ownership, sets this as parent More...

const QgsRuleBasedRenderer::RuleList &	children ()
	Returns all children rules of this rule. More...

QgsRuleBasedRenderer::Rule *	clone () const
	clone this rule, return new instance More...

QSet< int >	collectZLevels ()
	Gets all used z-levels from this rule and children. More...

bool	dependsOnScale () const

QgsRuleBasedRenderer::RuleList	descendants () const
	Returns all children, grand-children, grand-grand-children, grand-gra... More...

QString	description () const
	A human readable description for this rule. More...

QString	dump (int indent=0) const
	Dump for debug purpose. More...

QgsExpression *	filter () const
	A filter that will check if this rule applies. More...

QString	filterExpression () const
	A filter that will check if this rule applies. More...

QgsRuleBasedRenderer::Rule *	findRuleByKey (const QString &key)
	Try to find a rule given its unique key. More...

void	insertChild (int i, QgsRuleBasedRenderer::Rule *rule)
	add child rule, take ownership, sets this as parent More...

bool	isElse () const
	Check if this rule is an ELSE rule. More...

bool	isFilterOK (const QgsFeature &f, QgsRenderContext *context=nullptr) const
	Check if a given feature shall be rendered by this rule. More...

bool	isScaleOK (double scale) const
	Check if this rule applies for a given scale. More...

QString	label () const

QSet< QString >	legendKeysForFeature (const QgsFeature &feature, QgsRenderContext *context=nullptr)
	Returns which legend keys match the feature. More...

QgsLegendSymbolList	legendSymbolItems (int currentLevel=-1) const

double	maximumScale () const
	Returns the maximum map scale (i.e. More...

double	minimumScale () const
	Returns the minimum map scale (i.e. More...

bool	needsGeometry () const
	Returns `true` if this rule or one of its children needs the geometry to be applied. More...

Rule &	operator= (const Rule &rh)=delete
	Rules cannot be copied. More...

QgsRuleBasedRenderer::Rule *	parent ()
	The parent rule. More...

void	removeChild (QgsRuleBasedRenderer::Rule *rule)
	delete child rule More...

void	removeChildAt (int i)
	delete child rule More...

QgsRuleBasedRenderer::Rule::RenderResult	renderFeature (QgsRuleBasedRenderer::FeatureToRender &featToRender, QgsRenderContext &context, QgsRuleBasedRenderer::RenderQueue &renderQueue)
	Render a given feature, will recursively call subclasses and only render if the constraints apply. More...

QString	ruleKey () const
	Unique rule identifier (for identification of rule within renderer) More...

QgsRuleBasedRenderer::RuleList	rulesForFeature (const QgsFeature &feature, QgsRenderContext *context=nullptr, bool onlyActive=true)
	Returns the list of rules used to render the feature in a specific context. More...

QDomElement	save (QDomDocument &doc, QgsSymbolMap &symbolMap) const

void	setActive (bool state)
	Sets if this rule is active. More...

void	setDescription (const QString &description)
	Set a human readable description for this rule. More...

void	setFilterExpression (const QString &filterExp)
	Set the expression used to check if a given feature shall be rendered with this rule. More...

void	setIsElse (bool iselse)
	Sets if this rule is an ELSE rule. More...

void	setLabel (const QString &label)

void	setMaximumScale (double scale)
	Sets the maximum map scale (i.e. More...

void	setMinimumScale (double scale)
	Sets the minimum map scale (i.e. More...

void	setNormZLevels (const QMap< int, int > &zLevelsToNormLevels)
	assign normalized z-levels [0..N-1] for this rule's symbol for quick access during rendering More...

void	setRuleKey (const QString &key)
	Override the assigned rule key (should be used just internally by rule-based renderer) More...

void	setSymbol (QgsSymbol *sym)
	Sets a new symbol (or `nullptr`). Deletes old symbol. More...

bool	startRender (QgsRenderContext &context, const QgsFields &fields, QString &filter)
	prepare the rule for rendering and its children (build active children array) More...

void	stopRender (QgsRenderContext &context)
	Stop a rendering process. More...

QgsSymbol *	symbol ()

QgsSymbolList	symbols (const QgsRenderContext &context=QgsRenderContext()) const

QgsSymbolList	symbolsForFeature (const QgsFeature &feature, QgsRenderContext *context=nullptr)
	tell which symbols will be used to render the feature More...

QgsRuleBasedRenderer::Rule *	takeChild (QgsRuleBasedRenderer::Rule *rule)
	take child rule out, set parent as `nullptr` More...

QgsRuleBasedRenderer::Rule *	takeChildAt (int i)
	take child rule out, set parent as `nullptr` More...

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

QSet< QString >	usedAttributes (const QgsRenderContext &context) const
	Returns the attributes used to evaluate the expression of this rule. More...

bool	willRenderFeature (const QgsFeature &feature, QgsRenderContext *context=nullptr)
	only tell whether a feature will be rendered without actually rendering it More...

Static Public Member Functions
static QgsRuleBasedRenderer::Rule *	create (QDomElement &ruleElem, QgsSymbolMap &symbolMap)
	Create a rule from an XML definition. More...

static QgsRuleBasedRenderer::Rule *	createFromSld (QDomElement &element, QgsWkbTypes::GeometryType geomType)
	Create a rule from the SLD provided in element and for the specified geometry type. More...

Protected Member Functions
void	initFilter ()

Detailed Description

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

A rule consists of a symbol, filter expression and range of scales. If filter is empty, it matches all features. If scale range has both values zero, it matches all scales. If one of the min/max scale denominators is zero, there is no lower/upper bound for scales. A rule matches if both filter and scale range match.

Definition at line 139 of file qgsrulebasedrenderer.h.

Member Enumeration Documentation

◆ RenderResult

enum QgsRuleBasedRenderer::Rule::RenderResult

The result of rendering a rule.

Enumerator
Filtered	The rule does not apply.
Inactive	The rule is inactive.
Rendered	Something was rendered.

Definition at line 143 of file qgsrulebasedrenderer.h.

Constructor & Destructor Documentation

◆ Rule() [1/2]

QgsRuleBasedRenderer::Rule::Rule	(	QgsSymbol *	symbol,
		int	maximumScale = `0`,
		int	minimumScale = `0`,
		const QString &	filterExp = `QString()`,
		const QString &	label = `QString()`,
		const QString &	description = `QString()`,
		bool	elseRule = `false`
	)

Constructor takes ownership of the symbol.

Definition at line 43 of file qgsrulebasedrenderer.cpp.

◆ ~Rule()

QgsRuleBasedRenderer::Rule::~Rule ( )

Definition at line 60 of file qgsrulebasedrenderer.cpp.

◆ Rule() [2/2]

QgsRuleBasedRenderer::Rule::Rule ( const Rule & rh )

delete

Rules cannot be copied.

Member Function Documentation

◆ accept()

bool QgsRuleBasedRenderer::Rule::accept ( QgsStyleEntityVisitorInterface * visitor ) const

Accepts the specified symbology visitor, causing it to visit all child rules associated with the rule.

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

Since: QGIS 3.10

Definition at line 163 of file qgsrulebasedrenderer.cpp.

◆ active()

bool QgsRuleBasedRenderer::Rule::active ( ) const

inline

Returns if this rule is active.

Returns: true if the rule is active

Definition at line 250 of file qgsrulebasedrenderer.h.

◆ appendChild()

void QgsRuleBasedRenderer::Rule::appendChild ( QgsRuleBasedRenderer::Rule * rule )

add child rule, take ownership, sets this as parent

Definition at line 85 of file qgsrulebasedrenderer.cpp.

◆ children()

const QgsRuleBasedRenderer::RuleList& QgsRuleBasedRenderer::Rule::children ( )

inline

Returns all children rules of this rule.

Returns: A list of rules

Definition at line 386 of file qgsrulebasedrenderer.h.

◆ clone()

QgsRuleBasedRenderer::Rule * QgsRuleBasedRenderer::Rule::clone ( ) const

clone this rule, return new instance

Definition at line 309 of file qgsrulebasedrenderer.cpp.

◆ collectZLevels()

QSet< int > QgsRuleBasedRenderer::Rule::collectZLevels ( )

Gets all used z-levels from this rule and children.

Definition at line 524 of file qgsrulebasedrenderer.cpp.

◆ create()

QgsRuleBasedRenderer::Rule * QgsRuleBasedRenderer::Rule::create	(	QDomElement &	ruleElem,
		QgsSymbolMap &	symbolMap
	)

static

Create a rule from an XML definition.

Parameters

ruleElem	The XML rule element
symbolMap	Symbol map

Returns: A new rule

Definition at line 743 of file qgsrulebasedrenderer.cpp.

◆ createFromSld()

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

static

Create a rule from the SLD provided in element and for the specified geometry type.

Definition at line 801 of file qgsrulebasedrenderer.cpp.

◆ dependsOnScale()

bool QgsRuleBasedRenderer::Rule::dependsOnScale ( ) const

inline

Definition at line 204 of file qgsrulebasedrenderer.h.

◆ descendants()

QgsRuleBasedRenderer::RuleList QgsRuleBasedRenderer::Rule::descendants ( ) const

Returns all children, grand-children, grand-grand-children, grand-gra...

you get it

Returns: A list of descendant rules

Definition at line 790 of file qgsrulebasedrenderer.cpp.

◆ description()

QString QgsRuleBasedRenderer::Rule::description ( ) const

inline

A human readable description for this rule.

Returns: Description

Definition at line 243 of file qgsrulebasedrenderer.h.

◆ dump()

QString QgsRuleBasedRenderer::Rule::dump ( int indent = 0 ) const

Dump for debug purpose.

Parameters

indent How many characters to indent. Will increase by two with every of the recursive calls

Returns: A string representing this rule

Definition at line 192 of file qgsrulebasedrenderer.cpp.

◆ filter()

QgsExpression* QgsRuleBasedRenderer::Rule::filter ( ) const

inline

A filter that will check if this rule applies.

Returns: An expression

Definition at line 230 of file qgsrulebasedrenderer.h.

◆ filterExpression()

QString QgsRuleBasedRenderer::Rule::filterExpression ( ) const

inline

A filter that will check if this rule applies.

Returns: An expression

Definition at line 236 of file qgsrulebasedrenderer.h.

◆ findRuleByKey()

QgsRuleBasedRenderer::Rule * QgsRuleBasedRenderer::Rule::findRuleByKey ( const QString & key )

Try to find a rule given its unique key.

Since: QGIS 2.6

Definition at line 128 of file qgsrulebasedrenderer.cpp.

◆ initFilter()

void QgsRuleBasedRenderer::Rule::initFilter ( )

protected

Definition at line 66 of file qgsrulebasedrenderer.cpp.

◆ insertChild()

void QgsRuleBasedRenderer::Rule::insertChild	(	int	i,
		QgsRuleBasedRenderer::Rule *	rule
	)

add child rule, take ownership, sets this as parent

Definition at line 92 of file qgsrulebasedrenderer.cpp.

◆ isElse()

bool QgsRuleBasedRenderer::Rule::isElse ( ) const

inline

Check if this rule is an ELSE rule.

Returns: true if this rule is an else rule

Definition at line 438 of file qgsrulebasedrenderer.h.

◆ isFilterOK()

bool QgsRuleBasedRenderer::Rule::isFilterOK	(	const QgsFeature &	f,
		QgsRenderContext *	context = `nullptr`
	)		const

Check if a given feature shall be rendered by this rule.

Parameters

f	The feature to test
context	The context in which the rendering happens

Returns: true if the feature shall be rendered

Definition at line 286 of file qgsrulebasedrenderer.cpp.

◆ isScaleOK()

bool QgsRuleBasedRenderer::Rule::isScaleOK ( double scale ) const

Check if this rule applies for a given scale.

The scale value indicates the scale denominator, e.g. 1000.0 for a 1:1000 map. If set to 0, it will always return true.

Returns: If the rule will be evaluated at this scale

Definition at line 296 of file qgsrulebasedrenderer.cpp.

◆ label()

QString QgsRuleBasedRenderer::Rule::label ( ) const

inline

Definition at line 203 of file qgsrulebasedrenderer.h.

◆ legendKeysForFeature()

QSet< QString > QgsRuleBasedRenderer::Rule::legendKeysForFeature	(	const QgsFeature &	feature,
		QgsRenderContext *	context = `nullptr`
	)

Returns which legend keys match the feature.

Since: QGIS 2.14

Definition at line 673 of file qgsrulebasedrenderer.cpp.

◆ legendSymbolItems()

QgsLegendSymbolList QgsRuleBasedRenderer::Rule::legendSymbolItems ( int currentLevel = -1 ) const

Since: QGIS 2.6

Definition at line 269 of file qgsrulebasedrenderer.cpp.

◆ maximumScale()

double QgsRuleBasedRenderer::Rule::maximumScale ( ) const

inline

Returns the maximum map scale (i.e.

most "zoomed in" scale) at which the rule will be active. The scale value indicates the scale denominator, e.g. 1000.0 for a 1:1000 map. A scale of 0 indicates no maximum scale visibility.

See also: minimumScale(); setMaximumScale()

Since: QGIS 3.0

Definition at line 214 of file qgsrulebasedrenderer.h.

◆ minimumScale()

double QgsRuleBasedRenderer::Rule::minimumScale ( ) const

inline

Returns the minimum map scale (i.e.

most "zoomed out" scale) at which the rule will be active. The scale value indicates the scale denominator, e.g. 1000.0 for a 1:1000 map. A scale of 0 indicates no minimum scale visibility.

See also: maximumScale(); setMinimumScale()

Since: QGIS 3.0

Definition at line 224 of file qgsrulebasedrenderer.h.

◆ needsGeometry()

bool QgsRuleBasedRenderer::Rule::needsGeometry ( ) const

Returns true if this rule or one of its children needs the geometry to be applied.

Definition at line 229 of file qgsrulebasedrenderer.cpp.

◆ operator=()

Rule& QgsRuleBasedRenderer::Rule::operator= ( const Rule & rh )

delete

Rules cannot be copied.

◆ parent()

QgsRuleBasedRenderer::Rule* QgsRuleBasedRenderer::Rule::parent ( )

inline

The parent rule.

Returns: Parent rule

Definition at line 400 of file qgsrulebasedrenderer.h.

◆ removeChild()

void QgsRuleBasedRenderer::Rule::removeChild ( QgsRuleBasedRenderer::Rule * rule )

delete child rule

Definition at line 99 of file qgsrulebasedrenderer.cpp.

◆ removeChildAt()

void QgsRuleBasedRenderer::Rule::removeChildAt ( int i )

delete child rule

Definition at line 106 of file qgsrulebasedrenderer.cpp.

◆ renderFeature()

QgsRuleBasedRenderer::Rule::RenderResult QgsRuleBasedRenderer::Rule::renderFeature	(	QgsRuleBasedRenderer::FeatureToRender &	featToRender,
		QgsRenderContext &	context,
		QgsRuleBasedRenderer::RenderQueue &	renderQueue
	)

Render a given feature, will recursively call subclasses and only render if the constraints apply.

Parameters

featToRender	The feature to render
context	The rendering context
renderQueue	The rendering queue to which the feature should be added

Returns: The result of the rendering. In explicit if the feature is added to the queue or the reason for not rendering the feature.

Definition at line 568 of file qgsrulebasedrenderer.cpp.

◆ ruleKey()

QString QgsRuleBasedRenderer::Rule::ruleKey ( ) const

inline

Unique rule identifier (for identification of rule within renderer)

Since: QGIS 2.6

Definition at line 256 of file qgsrulebasedrenderer.h.

◆ rulesForFeature()

QgsRuleBasedRenderer::RuleList QgsRuleBasedRenderer::Rule::rulesForFeature	(	const QgsFeature &	feature,
		QgsRenderContext *	context = `nullptr`,
		bool	onlyActive = `true`
	)

Returns the list of rules used to render the feature in a specific context.

Parameters

feature	The feature for which rules have to be find
context	The rendering context
onlyActive	`true` to search for active rules only, `false` otherwise

Definition at line 707 of file qgsrulebasedrenderer.cpp.

◆ save()

QDomElement QgsRuleBasedRenderer::Rule::save	(	QDomDocument &	doc,
		QgsSymbolMap &	symbolMap
	)		const

Definition at line 321 of file qgsrulebasedrenderer.cpp.

◆ setActive()

void QgsRuleBasedRenderer::Rule::setActive ( bool state )

inline

Sets if this rule is active.

Parameters

state Determines if the rule should be activated or deactivated

Definition at line 304 of file qgsrulebasedrenderer.h.

◆ setDescription()

void QgsRuleBasedRenderer::Rule::setDescription ( const QString & description )

inline

Set a human readable description for this rule.

Parameters

description Description

Definition at line 298 of file qgsrulebasedrenderer.h.

◆ setFilterExpression()

void QgsRuleBasedRenderer::Rule::setFilterExpression ( const QString & filterExp )

Set the expression used to check if a given feature shall be rendered with this rule.

Parameters

filterExp An expression

Definition at line 263 of file qgsrulebasedrenderer.cpp.

◆ setIsElse()

void QgsRuleBasedRenderer::Rule::setIsElse ( bool iselse )

Sets if this rule is an ELSE rule.

Parameters

iselse If true, this rule is an ELSE rule

Definition at line 156 of file qgsrulebasedrenderer.cpp.

◆ setLabel()

void QgsRuleBasedRenderer::Rule::setLabel ( const QString & label )

inline

Definition at line 266 of file qgsrulebasedrenderer.h.

◆ setMaximumScale()

void QgsRuleBasedRenderer::Rule::setMaximumScale ( double scale )

inline

Sets the maximum map scale (i.e.

most "zoomed in" scale) at which the rule will be active. The scale value indicates the scale denominator, e.g. 1000.0 for a 1:1000 map. A scale of 0 indicates no maximum scale visibility.

See also: maximumScale(); setMinimumScale()

Definition at line 284 of file qgsrulebasedrenderer.h.

◆ setMinimumScale()

void QgsRuleBasedRenderer::Rule::setMinimumScale ( double scale )

inline

Sets the minimum map scale (i.e.

most "zoomed out" scale) at which the rule will be active. The scale value indicates the scale denominator, e.g. 1000.0 for a 1:1000 map. A scale of 0 indicates no minimum scale visibility.

See also: minimumScale(); setMaximumScale()

Definition at line 275 of file qgsrulebasedrenderer.h.

◆ setNormZLevels()

void QgsRuleBasedRenderer::Rule::setNormZLevels ( const QMap< int, int > & zLevelsToNormLevels )

assign normalized z-levels [0..N-1] for this rule's symbol for quick access during rendering

Note: not available in Python bindings

Definition at line 548 of file qgsrulebasedrenderer.cpp.

◆ setRuleKey()

void QgsRuleBasedRenderer::Rule::setRuleKey ( const QString & key )

inline

Override the assigned rule key (should be used just internally by rule-based renderer)

Since: QGIS 2.6

Definition at line 262 of file qgsrulebasedrenderer.h.

◆ setSymbol()

void QgsRuleBasedRenderer::Rule::setSymbol ( QgsSymbol * sym )

Sets a new symbol (or nullptr). Deletes old symbol.

Definition at line 258 of file qgsrulebasedrenderer.cpp.

◆ startRender()

bool QgsRuleBasedRenderer::Rule::startRender	(	QgsRenderContext &	context,
		const QgsFields &	fields,
		QString &	filter
	)

prepare the rule for rendering and its children (build active children array)

Definition at line 418 of file qgsrulebasedrenderer.cpp.

◆ stopRender()

void QgsRuleBasedRenderer::Rule::stopRender ( QgsRenderContext & context )

Stop a rendering process.

Used to clean up the internal state of this rule

Parameters

context The rendering context

Definition at line 728 of file qgsrulebasedrenderer.cpp.

◆ symbol()

QgsSymbol* QgsRuleBasedRenderer::Rule::symbol ( )

inline

Definition at line 202 of file qgsrulebasedrenderer.h.

◆ symbols()

QgsSymbolList QgsRuleBasedRenderer::Rule::symbols ( const QgsRenderContext & context = QgsRenderContext() ) const

Note: available in Python bindings as symbol2

Definition at line 244 of file qgsrulebasedrenderer.cpp.

◆ symbolsForFeature()

QgsSymbolList QgsRuleBasedRenderer::Rule::symbolsForFeature	(	const QgsFeature &	feature,
		QgsRenderContext *	context = `nullptr`
	)

tell which symbols will be used to render the feature

Definition at line 657 of file qgsrulebasedrenderer.cpp.

◆ takeChild()

QgsRuleBasedRenderer::Rule * QgsRuleBasedRenderer::Rule::takeChild ( QgsRuleBasedRenderer::Rule * rule )

take child rule out, set parent as nullptr

Definition at line 112 of file qgsrulebasedrenderer.cpp.

◆ takeChildAt()

QgsRuleBasedRenderer::Rule * QgsRuleBasedRenderer::Rule::takeChildAt ( int i )

take child rule out, set parent as nullptr

Definition at line 120 of file qgsrulebasedrenderer.cpp.

◆ toSld()

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

Saves the symbol layer as SLD.

Definition at line 353 of file qgsrulebasedrenderer.cpp.

◆ usedAttributes()

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

Returns the attributes used to evaluate the expression of this rule.

Returns: A set of attribute names

Definition at line 211 of file qgsrulebasedrenderer.cpp.

◆ willRenderFeature()

bool QgsRuleBasedRenderer::Rule::willRenderFeature	(	const QgsFeature &	feature,
		QgsRenderContext *	context = `nullptr`
	)

only tell whether a feature will be rendered without actually rendering it

Definition at line 621 of file qgsrulebasedrenderer.cpp.

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

/build/qgis-3.20.0+99unstable/src/core/symbology/qgsrulebasedrenderer.h
/build/qgis-3.20.0+99unstable/src/core/symbology/qgsrulebasedrenderer.cpp

Public Types

Public Member Functions

Static Public Member Functions

Protected Member Functions

Detailed Description

Member Enumeration Documentation

◆ RenderResult

Constructor & Destructor Documentation

◆ Rule() [1/2]

◆ ~Rule()

◆ Rule() [2/2]

Member Function Documentation

◆ accept()

◆ active()

◆ appendChild()

◆ children()

◆ clone()

◆ collectZLevels()

◆ create()

◆ createFromSld()

◆ dependsOnScale()

◆ descendants()

◆ description()

◆ dump()

◆ filter()

◆ filterExpression()

◆ findRuleByKey()

◆ initFilter()

◆ insertChild()

◆ isElse()

◆ isFilterOK()

◆ isScaleOK()

◆ label()

◆ legendKeysForFeature()

◆ legendSymbolItems()

◆ maximumScale()

◆ minimumScale()

◆ needsGeometry()

◆ operator=()

◆ parent()

◆ removeChild()

◆ removeChildAt()

◆ renderFeature()

◆ ruleKey()

◆ rulesForFeature()

◆ save()

◆ setActive()

◆ setDescription()

◆ setFilterExpression()

◆ setIsElse()

◆ setLabel()

◆ setMaximumScale()

◆ setMinimumScale()

◆ setNormZLevels()

◆ setRuleKey()

◆ setSymbol()

◆ startRender()

◆ stopRender()

◆ symbol()

◆ symbols()

◆ symbolsForFeature()

◆ takeChild()

◆ takeChildAt()

◆ toSld()

◆ usedAttributes()

◆ willRenderFeature()