QGIS API Documentation
3.16.0-Hannover (43b64b13f3)
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Implements a derived label provider for use with QgsLabelSink. More...
#include <qgslabelsink.h>
Public Member Functions | |
QgsLabelSinkProvider (QgsVectorLayer *layer, const QString &providerId, QgsLabelSink *sink, const QgsPalLayerSettings *settings) | |
Creates a rule based label sink provider which will draw/register labels in sink. More... | |
void | drawLabel (QgsRenderContext &context, pal::LabelPosition *label) const override |
Draw this label at the position determined by the labeling engine. More... | |
Public Member Functions inherited from QgsVectorLayerLabelProvider | |
QgsVectorLayerLabelProvider (QgsVectorLayer *layer, const QString &providerId, bool withFeatureLoop, const QgsPalLayerSettings *settings, const QString &layerName=QString()) | |
Convenience constructor to initialize the provider from given vector layer. More... | |
QgsVectorLayerLabelProvider (QgsWkbTypes::GeometryType geometryType, const QgsFields &fields, const QgsCoordinateReferenceSystem &crs, const QString &providerId, const QgsPalLayerSettings *settings, QgsMapLayer *layer, const QString &layerName=QString()) | |
Constructor to initialize the provider from any map layer (e.g. vector tile layer) More... | |
~QgsVectorLayerLabelProvider () override | |
void | drawLabel (QgsRenderContext &context, pal::LabelPosition *label) const override |
Draw this label at the position determined by the labeling engine. More... | |
void | drawLabelBackground (QgsRenderContext &context, pal::LabelPosition *label) const override |
Draw the background for the specified label. More... | |
void | drawUnplacedLabel (QgsRenderContext &context, pal::LabelPosition *label) const override |
Draw an unplaced label. More... | |
QList< QgsLabelFeature * > | labelFeatures (QgsRenderContext &context) override |
Returns list of label features (they are owned by the provider and thus deleted on its destruction) More... | |
virtual bool | prepare (QgsRenderContext &context, QSet< QString > &attributeNames) |
Prepare for registration of features. More... | |
virtual void | registerFeature (const QgsFeature &feature, QgsRenderContext &context, const QgsGeometry &obstacleGeometry=QgsGeometry(), const QgsSymbol *symbol=nullptr) |
Register a feature for labeling as one or more QgsLabelFeature objects stored into mLabels. More... | |
void | setFields (const QgsFields &fields) |
Sets fields of this label provider. More... | |
const QgsPalLayerSettings & | settings () const |
Returns the layer's settings. More... | |
void | startRender (QgsRenderContext &context) override |
To be called before rendering of labels begins. More... | |
void | stopRender (QgsRenderContext &context) override |
To be called after rendering is complete. More... | |
Public Member Functions inherited from QgsAbstractLabelProvider | |
QgsAbstractLabelProvider (QgsMapLayer *layer, const QString &providerId=QString()) | |
Construct the provider with default values. More... | |
virtual | ~QgsAbstractLabelProvider ()=default |
Flags | flags () const |
Flags associated with the provider. More... | |
QgsMapLayer * | layer () const |
Returns the associated layer, or nullptr if no layer is 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... | |
QString | name () const |
Name of the layer (for statistics, debugging etc.) - does not need to be unique. More... | |
QgsLabelObstacleSettings::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 QgsLabelingEngine *engine) |
Associate provider with a labeling engine (should be only called internally from QgsLabelingEngine) More... | |
virtual QList< QgsAbstractLabelProvider * > | subProviders () |
Returns 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... | |
Additional Inherited Members | |
Public Types inherited from QgsAbstractLabelProvider | |
enum | Flag { DrawLabels = 1 << 1, DrawAllLabels = 1 << 2, MergeConnectedLines = 1 << 3, CentroidMustBeInside = 1 << 4 } |
Static Public Member Functions inherited from QgsVectorLayerLabelProvider | |
static QgsGeometry | getPointObstacleGeometry (QgsFeature &fet, QgsRenderContext &context, const QgsSymbolList &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, QgsTextRenderer::TextPart drawType, double dpiRatio=1.0) const |
Internal label drawing method. More... | |
void | init () |
initialization method - called from constructors 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... | |
QgsWkbTypes::GeometryType | mLayerGeometryType |
Geometry type of layer. More... | |
QgsFeatureRenderer * | mRenderer = nullptr |
QgsPalLayerSettings | mSettings |
Layer's labeling configuration. More... | |
std::unique_ptr< QgsAbstractFeatureSource > | mSource |
Layer's feature source. More... | |
Protected Attributes inherited from QgsAbstractLabelProvider | |
const QgsLabelingEngine * | mEngine = nullptr |
Associated labeling engine. More... | |
Flags | mFlags |
Flags altering drawing and registration of features. More... | |
QgsWeakMapLayerPointer | mLayer |
Weak pointer to source layer. More... | |
QString | mLayerId |
Associated layer's ID, if applicable. More... | |
QString | mName |
Name of the layer. More... | |
QgsLabelObstacleSettings::ObstacleType | mObstacleType = QgsLabelObstacleSettings::PolygonBoundary |
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... | |
Implements a derived label provider for use with QgsLabelSink.
Definition at line 57 of file qgslabelsink.h.
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explicit |
Creates a rule based label sink provider which will draw/register labels in sink.
Definition at line 23 of file qgslabelsink.cpp.
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overridevirtual |
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 29 of file qgslabelsink.cpp.