A QgsLabelingEngine implementation, which only calculates the labeling solution during its run() method. More...

#include <qgslabelingengine.h>

Inheritance diagram for QgsStagedRenderLabelingEngine:

Public Member Functions
	QgsStagedRenderLabelingEngine ()
	Construct the labeling engine with default settings.

	QgsStagedRenderLabelingEngine (const QgsStagedRenderLabelingEngine &rh)=delete

void	finalize ()
	Finalizes and cleans up the engine following the rendering of labels for the last layer to be labeled (via renderLabelsForLayer() ).

QgsStagedRenderLabelingEngine &	operator= (const QgsStagedRenderLabelingEngine &rh)=delete

void	renderLabelsForLayer (QgsRenderContext &context, const QString &layerId)
	Renders all the labels which belong only to the layer with matching layerId to the specified render context.

void	run (QgsRenderContext &context) override
	Runs the labeling job.

Public Member Functions inherited from QgsLabelingEngine
	QgsLabelingEngine ()
	Construct the labeling engine with default settings.

	QgsLabelingEngine (const QgsLabelingEngine &rh)=delete

virtual	~QgsLabelingEngine ()
	Clean up everything (especially the registered providers)

QString	addProvider (QgsAbstractLabelProvider *provider)
	Adds a provider of label features.

const QgsLabelingEngineSettings &	engineSettings () const
	Gets associated labeling engine settings.

const QgsMapSettings &	mapSettings () const
	Gets associated map settings.

QgsLabelingEngine &	operator= (const QgsLabelingEngine &rh)=delete

QStringList	participatingLayerIds () const
	Returns a list of layer IDs for layers with providers in the engine.

QList< QgsMapLayer * >	participatingLayers () const
	Returns a list of layers with providers in the engine.

bool	prepare (QgsRenderContext &context)
	Prepares the engine for rendering in the specified context.

QgsAbstractLabelProvider *	providerById (const QString &id)
	Returns the provider with matching id, where id corresponds to the value returned by the addProvider() call.

void	removeProvider (QgsAbstractLabelProvider *provider)
	Remove provider if the provider's initialization failed. Provider instance is deleted.

QgsLabelingResults *	results () const
	For internal use by the providers.

void	setMapSettings (const QgsMapSettings &mapSettings)
	Associate map settings instance.

QgsLabelingResults *	takeResults ()
	Returns pointer to recently computed results and pass the ownership of results to the caller.

Additional Inherited Members
Static Public Member Functions inherited from QgsLabelingEngine
static void	drawLabelCandidateRect (pal::LabelPosition lp, QgsRenderContext &context, const QgsMapToPixel xform, QList< QgsLabelCandidate > *candidates=nullptr)
	Draws label candidate rectangles.

static void	drawLabelMetrics (pal::LabelPosition *label, const QgsMapToPixel &xform, QgsRenderContext &context, const QPointF &renderPoint)
	Draws label metrics.

Protected Member Functions inherited from QgsLabelingEngine
void	cleanup ()
	Cleans up the engine following a call to registerLabels() or solve().

void	drawLabels (QgsRenderContext &context, const QString &layerId=QString())
	Draws labels to the specified render context.

void	processProvider (QgsAbstractLabelProvider *provider, QgsRenderContext &context, pal::Pal &p)

void	registerLabels (QgsRenderContext &context)
	Runs the label registration step.

void	solve (QgsRenderContext &context)
	Solves the label problem.

Protected Attributes inherited from QgsLabelingEngine
std::vector< std::unique_ptr< QgsAbstractLabelingEngineRule > >	mEngineRules

QList< pal::LabelPosition * >	mLabels

QgsMapSettings	mMapSettings
	Associated map settings instance.

std::unique_ptr< pal::Pal >	mPal

std::unique_ptr< pal::Problem >	mProblem

QList< QgsAbstractLabelProvider * >	mProviders
	List of providers (the are owned by the labeling engine)

QHash< QString, QgsAbstractLabelProvider * >	mProvidersById

std::unique_ptr< QgsLabelingResults >	mResults
	Resulting labeling layout.

QList< QgsAbstractLabelProvider * >	mSubProviders
	List of labeling engine rules (owned by the labeling engine)

QList< pal::LabelPosition * >	mUnlabeled

Detailed Description

A QgsLabelingEngine implementation, which only calculates the labeling solution during its run() method.

The actual rendering of labels themselves is deferred to follow up calls to ....

Note: this class is not a part of public API yet. See notes in QgsLabelingEngine; not available in Python bindings

Since: QGIS 3.10

Definition at line 547 of file qgslabelingengine.h.

Constructor & Destructor Documentation

◆ QgsStagedRenderLabelingEngine() [1/2]

QgsStagedRenderLabelingEngine::QgsStagedRenderLabelingEngine ( )

Construct the labeling engine with default settings.

Definition at line 858 of file qgslabelingengine.cpp.

◆ QgsStagedRenderLabelingEngine() [2/2]

QgsStagedRenderLabelingEngine::QgsStagedRenderLabelingEngine ( const QgsStagedRenderLabelingEngine & rh )

delete

Member Function Documentation

◆ finalize()

void QgsStagedRenderLabelingEngine::finalize ( )

Finalizes and cleans up the engine following the rendering of labels for the last layer to be labeled (via renderLabelsForLayer() ).

Definition at line 887 of file qgslabelingengine.cpp.

◆ operator=()

QgsStagedRenderLabelingEngine & QgsStagedRenderLabelingEngine::operator= ( const QgsStagedRenderLabelingEngine & rh )

delete

◆ renderLabelsForLayer()

void QgsStagedRenderLabelingEngine::renderLabelsForLayer	(	QgsRenderContext &	context,
		const QString &	layerId
	)

Renders all the labels which belong only to the layer with matching layerId to the specified render context.

Definition at line 882 of file qgslabelingengine.cpp.

◆ run()

void QgsStagedRenderLabelingEngine::run ( QgsRenderContext & context )

overridevirtual

Runs the labeling job.

Depending on the concrete labeling engine class, this will either run the whole labeling job, including rendering the labels themselves, OR possibly just run the labeling job but leave the rendering to a future, deferred stage.

Implements QgsLabelingEngine.

Definition at line 864 of file qgslabelingengine.cpp.

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

/build/qgis-3.41.0+git20241225+af5edcb665c+99sid/src/core/labeling/qgslabelingengine.h
/build/qgis-3.41.0+git20241225+af5edcb665c+99sid/src/core/labeling/qgslabelingengine.cpp

Public Member Functions

Additional Inherited Members