A child rule for QgsRuleBasedLabeling. More...

#include <qgsrulebasedlabeling.h>

Public Types
enum	RegisterResult { Filtered = 0 , Inactive , Registered }
	The result of registering a rule. More...

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

	Rule (QgsPalLayerSettings *settings, double maximumScale=0, double minimumScale=0, const QString &filterExp=QString(), const QString &description=QString(), bool elseRule=false)
	takes ownership of settings, settings may be `nullptr` 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 (QgsRuleBasedLabeling::Rule *rule)
	add child rule, take ownership, sets this as parent More...

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

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

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

void	createSubProviders (QgsVectorLayer layer, RuleToProviderMap &subProviders, QgsRuleBasedLabelProvider provider)
	add providers More...

bool	dependsOnScale () const
	Determines if scale based labeling is active. More...

QgsRuleBasedLabeling::RuleList	descendants () const
	Returns all children, grand-children, grand-grand-children, grand-gra... you get it. More...

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

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

QgsRuleBasedLabeling::Rule *	findRuleByKey (const QString &key)
	Find a labeling rule thanks to its key. More...

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

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

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

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

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

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

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

const QgsRuleBasedLabeling::Rule *	parent () const
	The parent rule. More...

void	prepare (QgsRenderContext &context, QSet< QString > &attributeNames, RuleToProviderMap &subProviders)
	call prepare() on sub-providers and populate attributeNames More...

std::tuple< RegisterResult, QList< QgsLabelFeature * > >	registerFeature (const QgsFeature &feature, QgsRenderContext &context, RuleToProviderMap &subProviders, const QgsGeometry &obstacleGeometry=QgsGeometry(), const QgsSymbol *symbol=nullptr)
	Register individual features. More...

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

bool	requiresAdvancedEffects () const
	Returns `true` if this rule or any of its children requires advanced composition effects to render. More...

QString	ruleKey () const
	Unique rule identifier (for identification of rule within labeling, used as provider ID) More...

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

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

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

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

void	setSettings (QgsPalLayerSettings *settings)
	Sets new settings (or `nullptr`). Deletes old settings if any. More...

QgsPalLayerSettings *	settings () const
	Returns the labeling settings. More...

void	subProviderIds (QStringList &list) const
	append rule keys of descendants that contain valid settings (i.e. More...

Static Public Member Functions
static QgsRuleBasedLabeling::Rule *	create (const QDomElement &ruleElem, const QgsReadWriteContext &context)
	Create a rule from an XML definition. More...

Detailed Description

A child rule for QgsRuleBasedLabeling.

Since: QGIS 3.0

Definition at line 55 of file qgsrulebasedlabeling.h.

Member Enumeration Documentation

◆ RegisterResult

enum QgsRuleBasedLabeling::Rule::RegisterResult

The result of registering a rule.

Enumerator
Filtered	The rule does not apply.
Inactive	The rule is inactive.
Registered	Something was registered.

Definition at line 68 of file qgsrulebasedlabeling.h.

Constructor & Destructor Documentation

◆ Rule() [1/2]

QgsRuleBasedLabeling::Rule::Rule	(	QgsPalLayerSettings *	settings,
		double	maximumScale = `0`,
		double	minimumScale = `0`,
		const QString &	filterExp = `QString()`,
		const QString &	description = `QString()`,
		bool	elseRule = `false`
	)

takes ownership of settings, settings may be nullptr

Definition at line 58 of file qgsrulebasedlabeling.cpp.

◆ ~Rule()

QgsRuleBasedLabeling::Rule::~Rule ( )

Definition at line 72 of file qgsrulebasedlabeling.cpp.

◆ Rule() [2/2]

QgsRuleBasedLabeling::Rule::Rule ( const Rule & rh )

delete

Rules cannot be copied.

Member Function Documentation

◆ accept()

bool QgsRuleBasedLabeling::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 140 of file qgsrulebasedlabeling.cpp.

◆ active()

bool QgsRuleBasedLabeling::Rule::active ( ) const

inline

Returns if this rule is active.

Returns: true if the rule is active

Definition at line 125 of file qgsrulebasedlabeling.h.

◆ appendChild()

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

add child rule, take ownership, sets this as parent

Definition at line 180 of file qgsrulebasedlabeling.cpp.

◆ children() [1/2]

QgsRuleBasedLabeling::RuleList & QgsRuleBasedLabeling::Rule::children ( )

inline

Returns all children rules of this rule.

Returns: A list of rules

Definition at line 202 of file qgsrulebasedlabeling.h.

◆ children() [2/2]

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

inline

Returns all children rules of this rule.

Returns: A list of rules

Definition at line 195 of file qgsrulebasedlabeling.h.

◆ clone()

QgsRuleBasedLabeling::Rule * QgsRuleBasedLabeling::Rule::clone ( ) const

clone this rule, return new instance

Definition at line 231 of file qgsrulebasedlabeling.cpp.

◆ create()

QgsRuleBasedLabeling::Rule * QgsRuleBasedLabeling::Rule::create	(	const QDomElement &	ruleElem,
		const QgsReadWriteContext &	context
	)

static

Create a rule from an XML definition.

Parameters

ruleElem	The XML rule element
context	reading context

Returns: A new rule

Definition at line 242 of file qgsrulebasedlabeling.cpp.

◆ createSubProviders()

void QgsRuleBasedLabeling::Rule::createSubProviders	(	QgsVectorLayer *	layer,
		QgsRuleBasedLabeling::RuleToProviderMap &	subProviders,
		QgsRuleBasedLabelProvider *	provider
	)

add providers

Note: not available in Python bindings

Definition at line 310 of file qgsrulebasedlabeling.cpp.

◆ dependsOnScale()

bool QgsRuleBasedLabeling::Rule::dependsOnScale ( ) const

inline

Determines if scale based labeling is active.

Returns: true if scale based labeling is active

Definition at line 85 of file qgsrulebasedlabeling.h.

◆ descendants()

QgsRuleBasedLabeling::RuleList QgsRuleBasedLabeling::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 86 of file qgsrulebasedlabeling.cpp.

◆ description()

QString QgsRuleBasedLabeling::Rule::description ( ) const

inline

A human readable description for this rule.

Returns: Description

Definition at line 118 of file qgsrulebasedlabeling.h.

◆ filterExpression()

QString QgsRuleBasedLabeling::Rule::filterExpression ( ) const

inline

A filter that will check if this rule applies.

Returns: An expression

Definition at line 111 of file qgsrulebasedlabeling.h.

◆ findRuleByKey() [1/2]

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

Find a labeling rule thanks to its key.

Parameters

key	The key of the rule to find

Returns: The rule or nullptr if not found

Since: QGIS 3.0

Definition at line 217 of file qgsrulebasedlabeling.cpp.

◆ findRuleByKey() [2/2]

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

Try to find a rule given its unique key.

Definition at line 201 of file qgsrulebasedlabeling.cpp.

◆ insertChild()

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

add child rule, take ownership, sets this as parent

Definition at line 187 of file qgsrulebasedlabeling.cpp.

◆ isElse()

bool QgsRuleBasedLabeling::Rule::isElse ( ) const

inline

Check if this rule is an ELSE rule.

Returns: true if this rule is an else rule

Definition at line 132 of file qgsrulebasedlabeling.h.

◆ maximumScale()

double QgsRuleBasedLabeling::Rule::maximumScale ( ) const

inline

Returns the maximum map scale (i.e.

most "zoomed in" scale) at which the label 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 95 of file qgsrulebasedlabeling.h.

◆ minimumScale()

double QgsRuleBasedLabeling::Rule::minimumScale ( ) const

inline

Returns the minimum map scale (i.e.

most "zoomed out" scale) at which the label 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 105 of file qgsrulebasedlabeling.h.

◆ operator=()

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

delete

Rules cannot be copied.

◆ parent() [1/2]

QgsRuleBasedLabeling::Rule * QgsRuleBasedLabeling::Rule::parent ( )

inline

The parent rule.

Returns: Parent rule

Definition at line 223 of file qgsrulebasedlabeling.h.

◆ parent() [2/2]

const QgsRuleBasedLabeling::Rule * QgsRuleBasedLabeling::Rule::parent ( ) const

inline

The parent rule.

Returns: Parent rule

Definition at line 216 of file qgsrulebasedlabeling.h.

◆ prepare()

void QgsRuleBasedLabeling::Rule::prepare	(	QgsRenderContext &	context,
		QSet< QString > &	attributeNames,
		QgsRuleBasedLabeling::RuleToProviderMap &	subProviders
	)

call prepare() on sub-providers and populate attributeNames

Note: not available in Python bindings

Definition at line 327 of file qgsrulebasedlabeling.cpp.

◆ registerFeature()

std::tuple< QgsRuleBasedLabeling::Rule::RegisterResult, QList< QgsLabelFeature * > > QgsRuleBasedLabeling::Rule::registerFeature	(	const QgsFeature &	feature,
		QgsRenderContext &	context,
		QgsRuleBasedLabeling::RuleToProviderMap &	subProviders,
		const QgsGeometry &	obstacleGeometry = `QgsGeometry()`,
		const QgsSymbol *	symbol = `nullptr`
	)

Register individual features.

Returns result of registration, together with a list of all label features which were created as a result of registering feature. Ownership of these label features is not transferred (it has already been assigned to the label provider).

Note: not available in Python bindings

Definition at line 352 of file qgsrulebasedlabeling.cpp.

◆ removeChildAt()

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

delete child rule

Definition at line 194 of file qgsrulebasedlabeling.cpp.

◆ requiresAdvancedEffects()

bool QgsRuleBasedLabeling::Rule::requiresAdvancedEffects ( ) const

Returns true if this rule or any of its children requires advanced composition effects to render.

Definition at line 126 of file qgsrulebasedlabeling.cpp.

◆ ruleKey()

QString QgsRuleBasedLabeling::Rule::ruleKey ( ) const

inline

Unique rule identifier (for identification of rule within labeling, used as provider ID)

Definition at line 135 of file qgsrulebasedlabeling.h.

◆ save()

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

store labeling info to XML element

Definition at line 282 of file qgsrulebasedlabeling.cpp.

◆ setActive()

void QgsRuleBasedLabeling::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 176 of file qgsrulebasedlabeling.h.

◆ setDescription()

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

inline

Set a human readable description for this rule.

Parameters

description Description

Definition at line 170 of file qgsrulebasedlabeling.h.

◆ setFilterExpression()

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

inline

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

Parameters

filterExp An expression

Definition at line 163 of file qgsrulebasedlabeling.h.

◆ setIsElse()

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

inline

Sets if this rule is an ELSE rule.

Parameters

iselse If true, this rule is an ELSE rule

Definition at line 183 of file qgsrulebasedlabeling.h.

◆ setMaximumScale()

void QgsRuleBasedLabeling::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 156 of file qgsrulebasedlabeling.h.

◆ setMinimumScale()

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

inline

Sets the minimum map scale (i.e.

most "zoomed out" scale) at which the label 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 147 of file qgsrulebasedlabeling.h.

◆ setRuleKey()

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

inline

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

Definition at line 186 of file qgsrulebasedlabeling.h.

◆ setSettings()

void QgsRuleBasedLabeling::Rule::setSettings ( QgsPalLayerSettings * settings )

Sets new settings (or nullptr). Deletes old settings if any.

Definition at line 78 of file qgsrulebasedlabeling.cpp.

◆ settings()

QgsPalLayerSettings * QgsRuleBasedLabeling::Rule::settings ( ) const

inline

Returns the labeling settings.

May return nullptr.

Definition at line 78 of file qgsrulebasedlabeling.h.

◆ subProviderIds()

void QgsRuleBasedLabeling::Rule::subProviderIds ( QStringList & list ) const

append rule keys of descendants that contain valid settings (i.e.

they will be sub-providers)

Note: not available in Python bindings

Definition at line 168 of file qgsrulebasedlabeling.cpp.

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

/build/qgis-3.28.0+99sid/src/core/labeling/qgsrulebasedlabeling.h
/build/qgis-3.28.0+99sid/src/core/labeling/qgsrulebasedlabeling.cpp

Public Types

Public Member Functions

Static Public Member Functions

Detailed Description

Member Enumeration Documentation

◆ RegisterResult

Constructor & Destructor Documentation

◆ Rule() [1/2]

◆ ~Rule()

◆ Rule() [2/2]

Member Function Documentation

◆ accept()

◆ active()

◆ appendChild()

◆ children() [1/2]

◆ children() [2/2]

◆ clone()

◆ create()

◆ createSubProviders()

◆ dependsOnScale()

◆ descendants()

◆ description()

◆ filterExpression()

◆ findRuleByKey() [1/2]

◆ findRuleByKey() [2/2]

◆ insertChild()

◆ isElse()

◆ maximumScale()

◆ minimumScale()

◆ operator=()

◆ parent() [1/2]

◆ parent() [2/2]

◆ prepare()

◆ registerFeature()

◆ removeChildAt()

◆ requiresAdvancedEffects()

◆ ruleKey()

◆ save()

◆ setActive()

◆ setDescription()

◆ setFilterExpression()

◆ setIsElse()

◆ setMaximumScale()

◆ setMinimumScale()

◆ setRuleKey()

◆ setSettings()

◆ settings()

◆ subProviderIds()