QGIS API Documentation  2.18.3-Las Palmas (77b8c3d)
Public Member Functions | Protected Attributes | List of all members
QgsRuleBasedLabelProvider Class Reference

#include <qgsrulebasedlabeling.h>

Inheritance diagram for QgsRuleBasedLabelProvider:
Inheritance graph
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Public Member Functions

 QgsRuleBasedLabelProvider (const QgsRuleBasedLabeling &rules, QgsVectorLayer *layer, bool withFeatureLoop=true)
 
 ~QgsRuleBasedLabelProvider ()
 
virtual QgsVectorLayerLabelProvidercreateProvider (QgsVectorLayer *layer, const QString &providerId, bool withFeatureLoop, const QgsPalLayerSettings *settings)
 create a label provider More...
 
virtual bool prepare (const QgsRenderContext &context, QStringList &attributeNames) override
 Prepare for registration of features. More...
 
virtual void registerFeature (QgsFeature &feature, QgsRenderContext &context, QgsGeometry *obstacleGeometry=nullptr) override
 Register a feature for labeling as one or more QgsLabelFeature objects stored into mLabels. More...
 
virtual QList< QgsAbstractLabelProvider * > subProviders () override
 return subproviders More...
 
- Public Member Functions inherited from QgsVectorLayerLabelProvider
 QgsVectorLayerLabelProvider (QgsVectorLayer *layer, const QString &providerId, bool withFeatureLoop=true, const QgsPalLayerSettings *settings=nullptr, const QString &layerName=QString())
 Convenience constructor to initialize the provider from given vector layer. More...
 
 QgsVectorLayerLabelProvider (const QgsPalLayerSettings &settings, const QString &layerId, const QgsFields &fields, const QgsCoordinateReferenceSystem &crs, QgsAbstractFeatureSource *source, bool ownsSource, QgsFeatureRendererV2 *renderer=nullptr)
 Construct diagram provider with all the necessary configuration parameters. More...
 
 ~QgsVectorLayerLabelProvider ()
 
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...
 
- Public Member Functions inherited from QgsAbstractLabelProvider
 QgsAbstractLabelProvider (const QString &layerId=QString(), const QString &providerId=QString())
 Construct the provider with default values. More...
 
virtual ~QgsAbstractLabelProvider ()
 Vritual destructor. More...
 
Flags flags () const
 Flags associated with the provider. More...
 
QString layerId () const
 Returns ID of associated layer, or empty string if no layer is 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...
 
QString providerId () const
 Returns provider ID - useful in case there is more than one label provider within a layer (e.g. More...
 
void setEngine (const QgsLabelingEngineV2 *engine)
 Associate provider with a labeling engine (should be only called internally from QgsLabelingEngineV2) More...
 
QgsPalLayerSettings::UpsideDownLabels upsidedownLabels () const
 How to handle labels that would be upside down. More...
 

Protected Attributes

QgsRuleBasedLabeling mRules
 owned copy More...
 
QgsRuleBasedLabeling::RuleToProviderMap mSubProviders
 label providers are owned by labeling engine More...
 
- Protected Attributes inherited from QgsVectorLayerLabelProvider
QgsCoordinateReferenceSystem mCrs
 Layer's CRS. More...
 
QgsFields mFields
 Layer's fields. More...
 
QList< QgsLabelFeature * > mLabels
 List of generated. More...
 
QGis::GeometryType mLayerGeometryType
 Geometry type of layer. More...
 
bool mOwnsSource
 Whether layer's feature source is owned. More...
 
QgsFeatureRendererV2mRenderer
 
QgsPalLayerSettings mSettings
 Layer's labeling configuration. More...
 
QgsAbstractFeatureSourcemSource
 Layer's feature source. More...
 
- Protected Attributes inherited from QgsAbstractLabelProvider
const QgsLabelingEngineV2mEngine
 Associated labeling engine. More...
 
Flags mFlags
 Flags altering drawing and registration of features. More...
 
QString mLayerId
 Associated layer's ID, if applicable. 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...
 
QString mProviderId
 Associated provider ID (one layer may have multiple providers, e.g. in rule-based labeling) 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,
  LabelPerFeaturePart = 1 << 6
}
 
- Static Public Member Functions inherited from QgsVectorLayerLabelProvider
static QgsGeometrygetPointObstacleGeometry (QgsFeature &fet, QgsRenderContext &context, const QgsSymbolV2List &symbols)
 Returns the geometry for a point feature which should be used as an obstacle for labels. More...
 
- Protected Member Functions inherited from QgsVectorLayerLabelProvider
void drawLabelPrivate (pal::LabelPosition *label, QgsRenderContext &context, QgsPalLayerSettings &tmpLyr, QgsPalLabeling::DrawLabelType drawType, double dpiRatio=1.0) const
 Internal label drawing method. More...
 
void init ()
 initialization method - called from constructors More...
 

Detailed Description

Note
not available in Python bindings
this class is not a part of public API yet. See notes in QgsLabelingEngineV2

Definition at line 325 of file qgsrulebasedlabeling.h.

Constructor & Destructor Documentation

QgsRuleBasedLabelProvider::QgsRuleBasedLabelProvider ( const QgsRuleBasedLabeling rules,
QgsVectorLayer layer,
bool  withFeatureLoop = true 
)

Definition at line 18 of file qgsrulebasedlabeling.cpp.

QgsRuleBasedLabelProvider::~QgsRuleBasedLabelProvider ( )

Definition at line 25 of file qgsrulebasedlabeling.cpp.

Member Function Documentation

QgsVectorLayerLabelProvider * QgsRuleBasedLabelProvider::createProvider ( QgsVectorLayer layer,
const QString providerId,
bool  withFeatureLoop,
const QgsPalLayerSettings settings 
)
virtual

create a label provider

Reimplemented in QgsDxfRuleBasedLabelProvider.

Definition at line 30 of file qgsrulebasedlabeling.cpp.

bool QgsRuleBasedLabelProvider::prepare ( const QgsRenderContext context,
QStringList attributeNames 
)
overridevirtual

Prepare for registration of features.

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

Parameters
contextrender context.
attributeNameslist 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

Reimplemented from QgsVectorLayerLabelProvider.

Definition at line 35 of file qgsrulebasedlabeling.cpp.

void QgsRuleBasedLabelProvider::registerFeature ( QgsFeature feature,
QgsRenderContext context,
QgsGeometry obstacleGeometry = nullptr 
)
overridevirtual

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

Parameters
featurefeature to label
contextrender context. The QgsExpressionContext contained within the render context must have already had the feature and fields sets prior to calling this method.
obstacleGeometryoptional obstacle geometry, if a different geometry to the feature's geometry should be used as an obstacle for labels (eg, if the feature has been rendered with an offset point symbol, the obstacle geometry should represent the bounds of the offset symbol). If not set, the feature's original geometry will be used as an obstacle for labels.

Reimplemented from QgsVectorLayerLabelProvider.

Definition at line 45 of file qgsrulebasedlabeling.cpp.

QList< QgsAbstractLabelProvider * > QgsRuleBasedLabelProvider::subProviders ( )
overridevirtual

return subproviders

Reimplemented from QgsAbstractLabelProvider.

Definition at line 51 of file qgsrulebasedlabeling.cpp.

Member Data Documentation

QgsRuleBasedLabeling QgsRuleBasedLabelProvider::mRules
protected

owned copy

Definition at line 345 of file qgsrulebasedlabeling.h.

QgsRuleBasedLabeling::RuleToProviderMap QgsRuleBasedLabelProvider::mSubProviders
protected

label providers are owned by labeling engine

Definition at line 347 of file qgsrulebasedlabeling.h.


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