A labeling engine rule which prevents labels being placed too close to labels from a different layer. More...

#include <qgslabelingenginerule_impl.h>

Inheritance diagram for QgsLabelingEngineRuleMinimumDistanceLabelToLabel:

Public Member Functions
	QgsLabelingEngineRuleMinimumDistanceLabelToLabel ()

	~QgsLabelingEngineRuleMinimumDistanceLabelToLabel () override

bool	candidatesAreConflicting (const pal::LabelPosition lp1, const pal::LabelPosition lp2) const override
	Returns `true` if a labeling candidate lp1 conflicts with lp2 after applying the rule.

QgsLabelingEngineRuleMinimumDistanceLabelToLabel *	clone () const override
	Creates a clone of this rule.

QString	description () const override
	Returns a user-friendly description of the rule.

QString	displayType () const override
	Returns a user-friendly, translated string representing the rule type.

double	distance () const
	Returns the minimum permitted distance between labels from the labeledLayer() and the labels from the targetLayer().

Qgis::RenderUnit	distanceUnit () const
	Returns the units for the distance between labels from the labeledLayer() and the labels from the targetLayer().

const QgsMapUnitScale &	distanceUnitScale () const
	Returns the scaling for the distance between labels from the labeledLayer() and the labels from the targetLayer().

QString	id () const override
	Returns a string uniquely identifying the rule subclass.

bool	isAvailable () const override
	Returns `true` if the rule is available for use within the current QGIS environment.

QgsMapLayer *	labeledLayer () const
	Returns the layer providing the labels.

QgsRectangle	modifyCandidateConflictSearchBoundingBox (const QgsRectangle &candidateBounds) const override
	Returns a (possibly expanded) bounding box to use when searching for conflicts for a candidate.

bool	prepare (QgsRenderContext &context) override
	Prepares the rule.

void	readXml (const QDomElement &element, const QgsReadWriteContext &context) override
	Reads the rule properties from an XML element.

void	resolveReferences (const QgsProject *project) override
	Resolves reference to layers from stored layer ID.

void	setDistance (double distance)
	Sets the minimum permitted distance between labels from the labeledLayer() and the labels from the targetLayer().

void	setDistanceUnit (Qgis::RenderUnit unit)
	Sets the unit for the distance between labels from the labeledLayer() and the labels from the targetLayer().

void	setDistanceUnitScale (const QgsMapUnitScale &scale)
	Sets the scale for the distance between labels from the labeledLayer() and the labels from the targetLayer().

void	setLabeledLayer (QgsMapLayer *layer)
	Sets the layer providing the labels.

void	setTargetLayer (QgsMapLayer *layer)
	Sets the layer providing the labels which labels must be distant from.

QgsMapLayer *	targetLayer () const
	Returns the layer providing the labels which labels must be distant from.

void	writeXml (QDomDocument &doc, QDomElement &element, const QgsReadWriteContext &context) const override
	Writes the rule properties to an XML element.

Public Member Functions inherited from QgsAbstractLabelingEngineRule
virtual	~QgsAbstractLabelingEngineRule ()

bool	active () const
	Returns `true` if the rule is active.

virtual void	alterCandidateCost (pal::LabelPosition *candidate, QgsLabelingEngineContext &context) const
	Provides an opportunity for the rule to alter the cost for a candidate.

virtual bool	candidateIsIllegal (const pal::LabelPosition *candidate, QgsLabelingEngineContext &context) const
	Returns `true` if a labeling candidate violates the rule and should be eliminated.

QString	name () const
	Returns the name for this instance of the rule.

void	setActive (bool active)
	Sets whether the rule is active.

void	setName (const QString &name)
	Sets the name for this instance of the rule.

Additional Inherited Members
Protected Member Functions inherited from QgsAbstractLabelingEngineRule
virtual void	copyCommonProperties (QgsAbstractLabelingEngineRule *other) const
	Copies common properties from this object to an other.

Detailed Description

A labeling engine rule which prevents labels being placed too close to labels from a different layer.

Since: QGIS 3.40

Definition at line 256 of file qgslabelingenginerule_impl.h.

Constructor & Destructor Documentation

◆ QgsLabelingEngineRuleMinimumDistanceLabelToLabel()

QgsLabelingEngineRuleMinimumDistanceLabelToLabel::QgsLabelingEngineRuleMinimumDistanceLabelToLabel ( )

default

◆ ~QgsLabelingEngineRuleMinimumDistanceLabelToLabel()

QgsLabelingEngineRuleMinimumDistanceLabelToLabel::~QgsLabelingEngineRuleMinimumDistanceLabelToLabel ( )

overridedefault

Member Function Documentation

◆ candidatesAreConflicting()

bool QgsLabelingEngineRuleMinimumDistanceLabelToLabel::candidatesAreConflicting	(	const pal::LabelPosition *	lp1,
		const pal::LabelPosition *	lp2
	)		const

overridevirtual

Returns true if a labeling candidate lp1 conflicts with lp2 after applying the rule.

The default implementation returns false.

Reimplemented from QgsAbstractLabelingEngineRule.

Definition at line 436 of file qgslabelingenginerule_impl.cpp.

◆ clone()

QgsLabelingEngineRuleMinimumDistanceLabelToLabel * QgsLabelingEngineRuleMinimumDistanceLabelToLabel::clone ( ) const

overridevirtual

Creates a clone of this rule.

The caller takes ownership of the returned object.

Implements QgsAbstractLabelingEngineRule.

Definition at line 329 of file qgslabelingenginerule_impl.cpp.

◆ description()

QString QgsLabelingEngineRuleMinimumDistanceLabelToLabel::description ( ) const

overridevirtual

Returns a user-friendly description of the rule.

This should include the rule name() if set, and other useful details for users to quickly identify the rule's purpose when shown in a tooltip.

The returned string may contain HTML formatting.

Reimplemented from QgsAbstractLabelingEngineRule.

Definition at line 351 of file qgslabelingenginerule_impl.cpp.

◆ displayType()

QString QgsLabelingEngineRuleMinimumDistanceLabelToLabel::displayType ( ) const

overridevirtual

Returns a user-friendly, translated string representing the rule type.

Implements QgsAbstractLabelingEngineRule.

Definition at line 346 of file qgslabelingenginerule_impl.cpp.

◆ distance()

double QgsLabelingEngineRuleMinimumDistanceLabelToLabel::distance ( ) const

inline

Returns the minimum permitted distance between labels from the labeledLayer() and the labels from the targetLayer().

See also: setDistance(); distanceUnit()

Definition at line 317 of file qgslabelingenginerule_impl.h.

◆ distanceUnit()

Qgis::RenderUnit QgsLabelingEngineRuleMinimumDistanceLabelToLabel::distanceUnit ( ) const

inline

Returns the units for the distance between labels from the labeledLayer() and the labels from the targetLayer().

See also: setDistanceUnit(); distance()

Definition at line 335 of file qgslabelingenginerule_impl.h.

◆ distanceUnitScale()

const QgsMapUnitScale & QgsLabelingEngineRuleMinimumDistanceLabelToLabel::distanceUnitScale ( ) const

inline

Returns the scaling for the distance between labels from the labeledLayer() and the labels from the targetLayer().

See also: setDistanceUnitScale(); distance()

Definition at line 353 of file qgslabelingenginerule_impl.h.

◆ id()

QString QgsLabelingEngineRuleMinimumDistanceLabelToLabel::id ( ) const

overridevirtual

Returns a string uniquely identifying the rule subclass.

Implements QgsAbstractLabelingEngineRule.

Definition at line 341 of file qgslabelingenginerule_impl.cpp.

◆ isAvailable()

bool QgsLabelingEngineRuleMinimumDistanceLabelToLabel::isAvailable ( ) const

overridevirtual

Returns true if the rule is available for use within the current QGIS environment.

The base class method returns true.

Rules can return false if required dependencies are not available, e.g. if a library version is too old for the rule.

Reimplemented from QgsAbstractLabelingEngineRule.

Definition at line 366 of file qgslabelingenginerule_impl.cpp.

◆ labeledLayer()

QgsMapLayer * QgsLabelingEngineRuleMinimumDistanceLabelToLabel::labeledLayer ( ) const

Returns the layer providing the labels.

See also: setLabeledLayer()

Definition at line 469 of file qgslabelingenginerule_impl.cpp.

◆ modifyCandidateConflictSearchBoundingBox()

QgsRectangle QgsLabelingEngineRuleMinimumDistanceLabelToLabel::modifyCandidateConflictSearchBoundingBox ( const QgsRectangle & candidateBounds ) const

overridevirtual

Returns a (possibly expanded) bounding box to use when searching for conflicts for a candidate.

The return value is permitted to grow the bounding box, but may NOT shrink it.

The default implementation returns the same bounds.

Reimplemented from QgsAbstractLabelingEngineRule.

Definition at line 431 of file qgslabelingenginerule_impl.cpp.

◆ prepare()

bool QgsLabelingEngineRuleMinimumDistanceLabelToLabel::prepare ( QgsRenderContext & context )

overridevirtual

Prepares the rule.

This must be called on the main render thread, prior to commencing the render operation. Thread sensitive logic (such as creation of feature sources) can be performed in this method.

Implements QgsAbstractLabelingEngineRule.

Definition at line 425 of file qgslabelingenginerule_impl.cpp.