The QgsVectorLayerDiagramProvider class implements support for diagrams within the labeling engine. More...

#include <qgsvectorlayerdiagramprovider.h>

Inheritance diagram for QgsVectorLayerDiagramProvider:

Public Member Functions
	QgsVectorLayerDiagramProvider (QgsVectorLayer *layer, bool ownFeatureLoop=true)
	Convenience constructor to initialize the provider from given vector layer. More...

	QgsVectorLayerDiagramProvider (const QgsDiagramLayerSettings diagSettings, const QgsDiagramRendererV2 diagRenderer, const QString &layerId, const QgsFields &fields, const QgsCoordinateReferenceSystem &crs, QgsAbstractFeatureSource *source, bool ownsSource)
	Construct diagram provider with all the necessary configuration parameters. More...

	~QgsVectorLayerDiagramProvider ()
	Clean up. More...

virtual void	drawLabel (QgsRenderContext &context, pal::LabelPosition *label) const override
	draw this label at the position determined by the labeling engine More...

virtual QList< QgsLabelFeature * >	labelFeatures (QgsRenderContext &context) override
	Return list of label features (they are owned by the provider and thus deleted on its destruction) More...

virtual bool	prepare (const QgsRenderContext &context, QStringList &attributeNames)
	Prepare for registration of features. More...

virtual void	registerFeature (QgsFeature &feature, QgsRenderContext &context)
	Register a feature for labeling as one or more QgsLabelFeature objects stored into mFeatures. More...

Public Member Functions inherited from QgsAbstractLabelProvider
	QgsAbstractLabelProvider ()
	Construct the provider with default values. More...

virtual	~QgsAbstractLabelProvider ()
	Vritual destructor. More...

Flags	flags () const
	Flags associated with the provider. More...

unsigned int	linePlacementFlags () const
	For layers with linestring geometries - extra placement flags (or-ed combination of QgsPalLayerSettings::LinePlacementFlags) More...

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

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

QgsPalLayerSettings::Placement	placement () const
	What placement strategy to use for the labels. More...

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

void	setEngine (const QgsLabelingEngineV2 *engine)
	Associate provider with a labeling engine (should be only called internally from QgsLabelingEngineV2) More...

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

QgsPalLayerSettings::UpsideDownLabels	upsidedownLabels () const
	How to handle labels that would be upside down. More...

Protected Member Functions
void	init ()
	initialization method - called from constructors More...

QgsLabelFeature *	registerDiagram (QgsFeature &feat, QgsRenderContext &context)
	helper method to register one diagram feautre More...

Protected Attributes
QgsDiagramRendererV2 *	mDiagRenderer
	Diagram renderer instance (owned by mSettings) More...

QList< QgsLabelFeature * >	mFeatures
	List of generated label features (owned by the provider) More...

QgsFields	mFields
	Layer's fields. More...

QgsCoordinateReferenceSystem	mLayerCrs
	Layer's CRS. More...

QString	mLayerId
	ID of the layer. More...

bool	mOwnsSource
	Whether layer's feature source is owned. More...

QgsDiagramLayerSettings	mSettings
	Diagram layer settings. More...

QgsAbstractFeatureSource *	mSource
	Layer's feature source. More...

Protected Attributes inherited from QgsAbstractLabelProvider
const QgsLabelingEngineV2 *	mEngine
	Associated labeling engine. More...

Flags	mFlags
	Flags altering drawing and registration of features. More...

unsigned int	mLinePlacementFlags
	Extra placement flags for linestring geometries. More...

QString	mName
	Name of the layer. More...

QgsPalLayerSettings::ObstacleType	mObstacleType
	Type of the obstacle of feature geometries. More...

QgsPalLayerSettings::Placement	mPlacement
	Placement strategy. More...

double	mPriority
	Default priority of labels. More...

QgsPalLayerSettings::UpsideDownLabels	mUpsidedownLabels
	How to handle labels that would be upside down. More...

Additional Inherited Members
Public Types inherited from QgsAbstractLabelProvider
enum	Flag { DrawLabels = 1 << 1, DrawAllLabels = 1 << 2, MergeConnectedLines = 1 << 3, CentroidMustBeInside = 1 << 4, FitInPolygonOnly = 1 << 5, LabelPerFeaturePart = 1 << 6 }

Detailed Description

The QgsVectorLayerDiagramProvider class implements support for diagrams within the labeling engine.

Parameters for the diagrams are taken from the layer settings.

Note: added in QGIS 2.12

Definition at line 54 of file qgsvectorlayerdiagramprovider.h.

Constructor & Destructor Documentation

QgsVectorLayerDiagramProvider::QgsVectorLayerDiagramProvider	(	QgsVectorLayer *	layer,
		bool	ownFeatureLoop = `true`
	)

explicit

Convenience constructor to initialize the provider from given vector layer.

Definition at line 47 of file qgsvectorlayerdiagramprovider.cpp.

QgsVectorLayerDiagramProvider::QgsVectorLayerDiagramProvider	(	const QgsDiagramLayerSettings *	diagSettings,
		const QgsDiagramRendererV2 *	diagRenderer,
		const QString &	layerId,
		const QgsFields &	fields,
		const QgsCoordinateReferenceSystem &	crs,
		QgsAbstractFeatureSource *	source,
		bool	ownsSource
	)

Construct diagram provider with all the necessary configuration parameters.

Definition at line 27 of file qgsvectorlayerdiagramprovider.cpp.

QgsVectorLayerDiagramProvider::~QgsVectorLayerDiagramProvider ( )

Clean up.

Definition at line 69 of file qgsvectorlayerdiagramprovider.cpp.

Member Function Documentation

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

overridevirtual

draw this label at the position determined by the labeling engine

Implements QgsAbstractLabelProvider.

Definition at line 113 of file qgsvectorlayerdiagramprovider.cpp.

void QgsVectorLayerDiagramProvider::init ( )

protected

initialization method - called from constructors

Definition at line 60 of file qgsvectorlayerdiagramprovider.cpp.

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

overridevirtual

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

Implements QgsAbstractLabelProvider.

Definition at line 80 of file qgsvectorlayerdiagramprovider.cpp.

bool QgsVectorLayerDiagramProvider::prepare	(	const QgsRenderContext &	context,
		QStringList &	attributeNames
	)

virtual

Prepare for registration of features.

Must be called after provider has been added to engine (uses its map settings)

Parameters

context	render context.
attributeNames	list of attribute names to which additional required attributes shall be added

Returns: Whether the preparation was successful - if not, the provider shall not be used

Definition at line 157 of file qgsvectorlayerdiagramprovider.cpp.

QgsLabelFeature * QgsVectorLayerDiagramProvider::registerDiagram	(	QgsFeature &	feat,
		QgsRenderContext &	context
	)

protected

helper method to register one diagram feautre

Definition at line 236 of file qgsvectorlayerdiagramprovider.cpp.

void QgsVectorLayerDiagramProvider::registerFeature	(	QgsFeature &	feature,
		QgsRenderContext &	context
	)

virtual

Register a feature for labeling as one or more QgsLabelFeature objects stored into mFeatures.

Parameters

feature	feature for diagram
context	render context. The QgsExpressionContext contained within the render context must have already had the feature and fields sets prior to calling this method.

Definition at line 228 of file qgsvectorlayerdiagramprovider.cpp.