QGIS API Documentation
3.0.2-Girona (307d082)
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The QgsAbstractLabelProvider class is an interface class. More...
#include <qgslabelingengine.h>
Public Types | |
enum | Flag { DrawLabels = 1 << 1, DrawAllLabels = 1 << 2, MergeConnectedLines = 1 << 3, CentroidMustBeInside = 1 << 4, LabelPerFeaturePart = 1 << 6 } |
Public Member Functions | |
QgsAbstractLabelProvider (QgsMapLayer *layer, const QString &providerId=QString()) | |
Construct the provider with default values. More... | |
virtual | ~QgsAbstractLabelProvider ()=default |
virtual void | drawLabel (QgsRenderContext &context, pal::LabelPosition *label) const =0 |
draw this label at the position determined by the labeling engine More... | |
Flags | flags () const |
Flags associated with the provider. More... | |
virtual QList< QgsLabelFeature * > | labelFeatures (QgsRenderContext &context)=0 |
Return list of label features (they are owned by the provider and thus deleted on its destruction) 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... | |
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 QgsLabelingEngine *engine) |
Associate provider with a labeling engine (should be only called internally from QgsLabelingEngine) 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 Attributes | |
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... | |
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... | |
The QgsAbstractLabelProvider class is an interface class.
Implementations return list of labels and their associated geometries - these are used by QgsLabelingEngine to compute the final layout of labels.
Implementations also take care of drawing the returned final label positions.
Definition at line 43 of file qgslabelingengine.h.
Definition at line 55 of file qgslabelingengine.h.
QgsAbstractLabelProvider::QgsAbstractLabelProvider | ( | QgsMapLayer * | layer, |
const QString & | providerId = QString() |
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Construct the provider with default values.
Definition at line 362 of file qgslabelingengine.cpp.
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virtualdefault |
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pure virtual |
draw this label at the position determined by the labeling engine
Implemented in QgsDxfRuleBasedLabelProvider, QgsVectorLayerDiagramProvider, QgsVectorLayerLabelProvider, and QgsDxfLabelProvider.
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Flags associated with the provider.
Definition at line 91 of file qgslabelingengine.h.
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pure virtual |
Return list of label features (they are owned by the provider and thus deleted on its destruction)
Implemented in QgsVectorLayerDiagramProvider, and QgsVectorLayerLabelProvider.
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inline |
Returns the associated layer, or nullptr if no layer is associated with the provider.
Definition at line 81 of file qgslabelingengine.h.
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Returns ID of associated layer, or empty string if no layer is associated with the provider.
Definition at line 78 of file qgslabelingengine.h.
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For layers with linestring geometries - extra placement flags (or-ed combination of QgsPalLayerSettings::LinePlacementFlags)
Definition at line 97 of file qgslabelingengine.h.
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Name of the layer (for statistics, debugging etc.) - does not need to be unique.
Definition at line 75 of file qgslabelingengine.h.
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How the feature geometries will work as obstacles.
Definition at line 103 of file qgslabelingengine.h.
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What placement strategy to use for the labels.
Definition at line 94 of file qgslabelingengine.h.
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Default priority of labels (may be overridden by individual labels)
Definition at line 100 of file qgslabelingengine.h.
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Returns provider ID - useful in case there is more than one label provider within a layer (e.g.
in case of rule-based labeling - provider ID = rule's key). May be empty string if layer ID is sufficient for identification of provider's configuration.
Definition at line 88 of file qgslabelingengine.h.
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Associate provider with a labeling engine (should be only called internally from QgsLabelingEngine)
Definition at line 53 of file qgslabelingengine.h.
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inlinevirtual |
Return list of child providers - useful if the provider needs to put labels into more layers with different configuration.
Reimplemented in QgsRuleBasedLabelProvider.
Definition at line 72 of file qgslabelingengine.h.
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How to handle labels that would be upside down.
Definition at line 106 of file qgslabelingengine.h.
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protected |
Associated labeling engine.
Definition at line 110 of file qgslabelingengine.h.
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Flags altering drawing and registration of features.
Definition at line 121 of file qgslabelingengine.h.
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Weak pointer to source layer.
Definition at line 117 of file qgslabelingengine.h.
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Associated layer's ID, if applicable.
Definition at line 115 of file qgslabelingengine.h.
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Extra placement flags for linestring geometries.
Definition at line 125 of file qgslabelingengine.h.
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Name of the layer.
Definition at line 113 of file qgslabelingengine.h.
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Type of the obstacle of feature geometries.
Definition at line 129 of file qgslabelingengine.h.
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Placement strategy.
Definition at line 123 of file qgslabelingengine.h.
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Default priority of labels.
Definition at line 127 of file qgslabelingengine.h.
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Associated provider ID (one layer may have multiple providers, e.g. in rule-based labeling)
Definition at line 119 of file qgslabelingengine.h.
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How to handle labels that would be upside down.
Definition at line 131 of file qgslabelingengine.h.