Implements labeling support for raster layers. More...

#include <qgsrasterlabeling.h>

Inheritance diagram for QgsRasterLayerLabelProvider:

Public Member Functions
	QgsRasterLayerLabelProvider (QgsRasterLayer *layer)
	Constructor for QgsRasterLayerLabelProvider.

	~QgsRasterLayerLabelProvider () final

void	addLabel (const QgsPoint &mapPoint, const QString &text, QgsRenderContext &context)
	Adds a label at the specified point in map coordinates.

int	band () const
	Returns the raster band to use for label values.

void	drawLabel (QgsRenderContext &context, pal::LabelPosition *label) const final
	Draw this label at the position determined by the labeling engine.

void	generateLabels (QgsRenderContext &context, QgsRasterPipe pipe, QgsRasterViewPort rasterViewPort, QgsRasterLayerRendererFeedback *feedback)
	Generates the labels, given a render context and input pipe.

QList< QgsLabelFeature * >	labelFeatures (QgsRenderContext &) final
	Returns list of label features (they are owned by the provider and thus deleted on its destruction)

QgsNumericFormat *	numericFormat ()
	Returns the numeric format to be used for the labels.

void	setBand (int band)
	Sest the raster band to use for label values.

void	setNumericFormat (std::unique_ptr< QgsNumericFormat > format)
	Sets the numeric format used for the labels.

void	setPlacementSettings (const QgsLabelPlacementSettings &settings)
	Sets the label placement settings.

void	setPriority (double priority)
	Sets the priority of labels.

void	setResampleMethod (Qgis::RasterResamplingMethod method)
	Sets the resampling method to use when the raster labels are being resampled over neighboring pixels.

void	setResampleOver (int pixels)
	Sets the number of neighboring pixels to resample over, when labels are showing values resampled over neighboring pixels.

void	setTextFormat (const QgsTextFormat &format)
	Sets the text format used for rendering the labels.

void	setThinningSettings (const QgsLabelThinningSettings &settings)
	Sets the label thinning settings.

void	setZIndex (double index)
	Sets the Z-Index of the labels.

void	startRender (QgsRenderContext &context) final
	To be called before rendering of labels begins.

Public Member Functions inherited from QgsAbstractLabelProvider
	QgsAbstractLabelProvider (QgsMapLayer *layer, const QString &providerId=QString())
	Construct the provider with default values.

virtual	~QgsAbstractLabelProvider ()=default

virtual void	drawLabelBackground (QgsRenderContext &context, pal::LabelPosition *label) const
	Draw the background for the specified label.

virtual void	drawUnplacedLabel (QgsRenderContext &context, pal::LabelPosition *label) const
	Draw an unplaced label.

Flags	flags () const
	Flags associated with the provider.

QgsMapLayer *	layer () const
	Returns the associated layer, or `nullptr` if no layer is associated with the provider.

QgsExpressionContextScope *	layerExpressionContextScope () const
	Returns the expression context scope created from the layer associated with this provider.

QString	layerId () const
	Returns ID of associated layer, or empty string if no layer is associated with the provider.

double	layerReferenceScale () const
	Returns the symbology reference scale of the layer associated with this provider.

QString	name () const
	Name of the layer (for statistics, debugging etc.) - does not need to be unique.

QgsLabelObstacleSettings::ObstacleType	obstacleType () const
	How the feature geometries will work as obstacles.

Qgis::LabelPlacement	placement () const
	What placement strategy to use for the labels.

double	priority () const
	Default priority of labels (may be overridden by individual labels).

QString	providerId () const
	Returns provider ID - useful in case there is more than one label provider within a layer (e.g.

void	setEngine (const QgsLabelingEngine *engine)
	Associate provider with a labeling engine (should be only called internally from QgsLabelingEngine)

virtual void	stopRender (QgsRenderContext &context)
	To be called after rendering is complete.

virtual QList< QgsAbstractLabelProvider * >	subProviders ()
	Returns list of child providers - useful if the provider needs to put labels into more layers with different configuration.

Qgis::UpsideDownLabelHandling	upsidedownLabels () const
	How to handle labels that would be upside down.

Additional Inherited Members
Public Types inherited from QgsAbstractLabelProvider
enum	Flag { DrawLabels = 1 << 1 , MergeConnectedLines = 1 << 3 , CentroidMustBeInside = 1 << 4 }

typedef QFlags< Flag >	Flags

Protected Attributes inherited from QgsAbstractLabelProvider
const QgsLabelingEngine *	mEngine = nullptr
	Associated labeling engine.

Flags	mFlags = DrawLabels
	Flags altering drawing and registration of features.

QgsWeakMapLayerPointer	mLayer
	Weak pointer to source layer.

QString	mLayerId
	Associated layer's ID, if applicable.

QString	mName
	Name of the layer.

QgsLabelObstacleSettings::ObstacleType	mObstacleType = QgsLabelObstacleSettings::ObstacleType::PolygonBoundary
	Type of the obstacle of feature geometries.

Qgis::LabelPlacement	mPlacement = Qgis::LabelPlacement::AroundPoint
	Placement strategy.

double	mPriority = 0.5
	Default priority of labels. 0 = highest priority, 1 = lowest priority.

QString	mProviderId
	Associated provider ID (one layer may have multiple providers, e.g. in rule-based labeling)

Qgis::UpsideDownLabelHandling	mUpsidedownLabels = Qgis::UpsideDownLabelHandling::FlipUpsideDownLabels
	How to handle labels that would be upside down.

Detailed Description

Implements labeling support for raster layers.

Note: Not available in Python bindings

Since: QGIS 3.42

Definition at line 45 of file qgsrasterlabeling.h.

Constructor & Destructor Documentation

◆ QgsRasterLayerLabelProvider()

QgsRasterLayerLabelProvider::QgsRasterLayerLabelProvider ( QgsRasterLayer * layer )

explicit

Constructor for QgsRasterLayerLabelProvider.

Definition at line 34 of file qgsrasterlabeling.cpp.

◆ ~QgsRasterLayerLabelProvider()

QgsRasterLayerLabelProvider::~QgsRasterLayerLabelProvider ( )

final

Definition at line 42 of file qgsrasterlabeling.cpp.

Member Function Documentation

◆ addLabel()

void QgsRasterLayerLabelProvider::addLabel	(	const QgsPoint &	mapPoint,
		const QString &	text,
		QgsRenderContext &	context
	)

Adds a label at the specified point in map coordinates.

Definition at line 47 of file qgsrasterlabeling.cpp.

◆ band()

int QgsRasterLayerLabelProvider::band ( ) const

inline

Returns the raster band to use for label values.

See also: setBand()

Definition at line 93 of file qgsrasterlabeling.h.

◆ drawLabel()

void QgsRasterLayerLabelProvider::drawLabel	(	QgsRenderContext &	context,
		pal::LabelPosition *	label
	)		const

finalvirtual

Draw this label at the position determined by the labeling engine.

Before any calls to drawLabel(), a provider should be prepared for rendering by a call to startRender() and a corresponding call to stopRender().

Implements QgsAbstractLabelProvider.

Definition at line 114 of file qgsrasterlabeling.cpp.

◆ generateLabels()

void QgsRasterLayerLabelProvider::generateLabels	(	QgsRenderContext &	context,
		QgsRasterPipe *	pipe,
		QgsRasterViewPort *	rasterViewPort,
		QgsRasterLayerRendererFeedback *	feedback
	)

Generates the labels, given a render context and input pipe.

Definition at line 158 of file qgsrasterlabeling.cpp.

◆ labelFeatures()

QList< QgsLabelFeature * > QgsRasterLayerLabelProvider::labelFeatures ( QgsRenderContext & context )

finalvirtual

Returns list of label features (they are owned by the provider and thus deleted on its destruction)

Implements QgsAbstractLabelProvider.

Definition at line 109 of file qgsrasterlabeling.cpp.

◆ numericFormat()

QgsNumericFormat * QgsRasterLayerLabelProvider::numericFormat ( )

Returns the numeric format to be used for the labels.

See also: setNumericFormat()

Definition at line 94 of file qgsrasterlabeling.cpp.

◆ setBand()

void QgsRasterLayerLabelProvider::setBand ( int band )

inline

Sest the raster band to use for label values.

See also: band()

Definition at line 100 of file qgsrasterlabeling.h.

◆ setNumericFormat()

void QgsRasterLayerLabelProvider::setNumericFormat ( std::unique_ptr< QgsNumericFormat > format )

Sets the numeric format used for the labels.

See also: numericFormat()

Definition at line 89 of file qgsrasterlabeling.cpp.

◆ setPlacementSettings()

void QgsRasterLayerLabelProvider::setPlacementSettings ( const QgsLabelPlacementSettings & settings )

inline

Sets the label placement settings.

Definition at line 112 of file qgsrasterlabeling.h.

◆ setPriority()

void QgsRasterLayerLabelProvider::setPriority ( double priority )

inline

Sets the priority of labels.

This is a value between 0 to 1, where 0 = highest priority and 1 = lowest priority.

Definition at line 107 of file qgsrasterlabeling.h.

◆ setResampleMethod()

void QgsRasterLayerLabelProvider::setResampleMethod ( Qgis::RasterResamplingMethod method )

Sets the resampling method to use when the raster labels are being resampled over neighboring pixels.

See also: setResampleOver()

Definition at line 99 of file qgsrasterlabeling.cpp.

◆ setResampleOver()

void QgsRasterLayerLabelProvider::setResampleOver ( int pixels )

Sets the number of neighboring pixels to resample over, when labels are showing values resampled over neighboring pixels.

See also: setResampleMethod()

Definition at line 104 of file qgsrasterlabeling.cpp.

◆ setTextFormat()

void QgsRasterLayerLabelProvider::setTextFormat ( const QgsTextFormat & format )

Sets the text format used for rendering the labels.

Definition at line 84 of file qgsrasterlabeling.cpp.

◆ setThinningSettings()

void QgsRasterLayerLabelProvider::setThinningSettings ( const QgsLabelThinningSettings & settings )

inline

Sets the label thinning settings.

Definition at line 124 of file qgsrasterlabeling.h.

◆ setZIndex()

void QgsRasterLayerLabelProvider::setZIndex ( double index )

inline

Sets the Z-Index of the labels.

Labels with a higher z-index are rendered on top of labels with a lower z-index.

Definition at line 119 of file qgsrasterlabeling.h.

◆ startRender()

void QgsRasterLayerLabelProvider::startRender ( QgsRenderContext & context )

finalvirtual

To be called before rendering of labels begins.

Must be accompanied by a corresponding call to stopRender()

Since: QGIS 3.10

Reimplemented from QgsAbstractLabelProvider.

Definition at line 127 of file qgsrasterlabeling.cpp.

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

/build/qgis-3.41.0+git20241225+af5edcb665c+99sid/src/core/raster/qgsrasterlabeling.h
/build/qgis-3.41.0+git20241225+af5edcb665c+99sid/src/core/raster/qgsrasterlabeling.cpp

Public Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ QgsRasterLayerLabelProvider()

◆ ~QgsRasterLayerLabelProvider()

Member Function Documentation

◆ addLabel()

◆ band()

◆ drawLabel()

◆ generateLabels()

◆ labelFeatures()

◆ numericFormat()

◆ setBand()

◆ setNumericFormat()

◆ setPlacementSettings()

◆ setPriority()

◆ setResampleMethod()

◆ setResampleOver()

◆ setTextFormat()

◆ setThinningSettings()

◆ setZIndex()

◆ startRender()