QGIS API Documentation  3.37.0-Master (a5b4d9743e8)
qgsvectorlayerlabelprovider.h
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1 /***************************************************************************
2  qgsvectorlayerlabelprovider.h
3  --------------------------------------
4  Date : September 2015
5  Copyright : (C) 2015 by Martin Dobias
6  Email : wonder dot sk at gmail dot com
7  ***************************************************************************
8  * *
9  * This program is free software; you can redistribute it and/or modify *
10  * it under the terms of the GNU General Public License as published by *
11  * the Free Software Foundation; either version 2 of the License, or *
12  * (at your option) any later version. *
13  * *
14  ***************************************************************************/
15 
16 #ifndef QGSVECTORLAYERLABELPROVIDER_H
17 #define QGSVECTORLAYERLABELPROVIDER_H
18 
19 #define SIP_NO_FILE
20 
21 #include "qgis_core.h"
22 #include "qgslabelingengine.h"
23 #include "qgsrenderer.h"
24 #include "qgspallabeling.h"
25 
27 class QgsFeatureRenderer;
28 class QgsSymbol;
29 
40 {
41  public:
42 
45  const QString &providerId,
46  bool withFeatureLoop,
47  const QgsPalLayerSettings *settings,
48  const QString &layerName = QString() );
49 
51  explicit QgsVectorLayerLabelProvider( Qgis::GeometryType geometryType,
52  const QgsFields &fields,
54  const QString &providerId,
55  const QgsPalLayerSettings *settings,
56  QgsMapLayer *layer,
57  const QString &layerName = QString() );
58 
59  ~QgsVectorLayerLabelProvider() override;
60 
61  QList<QgsLabelFeature *> labelFeatures( QgsRenderContext &context ) override;
62 
63  void drawLabelBackground( QgsRenderContext &context, pal::LabelPosition *label ) const override;
64  void drawLabel( QgsRenderContext &context, pal::LabelPosition *label ) const override;
65  void drawUnplacedLabel( QgsRenderContext &context, pal::LabelPosition *label ) const override;
66  void startRender( QgsRenderContext &context ) override;
67  void stopRender( QgsRenderContext &context ) override;
68 
69  // new virtual methods
70 
77  virtual bool prepare( QgsRenderContext &context, QSet<QString> &attributeNames );
78 
93  virtual QList< QgsLabelFeature * > registerFeature( const QgsFeature &feature, QgsRenderContext &context, const QgsGeometry &obstacleGeometry = QgsGeometry(), const QgsSymbol *symbol = nullptr );
94 
103  static QgsGeometry getPointObstacleGeometry( QgsFeature &fet, QgsRenderContext &context, const QgsSymbolList &symbols );
104 
109  const QgsPalLayerSettings &settings() const;
110 
117  void setFields( const QgsFields &fields );
118 
119  protected:
121  void init();
123  void drawLabelPrivate( pal::LabelPosition *label, QgsRenderContext &context, QgsPalLayerSettings &tmpLyr, Qgis::TextComponent drawType, double dpiRatio = 1.0 ) const;
124 
125  protected:
130 
131  QgsFeatureRenderer *mRenderer = nullptr;
132 
133  // these are needed only if using own renderer loop
134 
140  std::unique_ptr<QgsAbstractFeatureSource> mSource;
141 
143  QList<QgsLabelFeature *> mLabels;
144 
145  private:
146 
147  friend class TestQgsLabelingEngine;
149 
150  void drawCallout( QgsRenderContext &context, pal::LabelPosition *label ) const;
151 };
152 
153 #endif // QGSVECTORLAYERLABELPROVIDER_H
GeometryType
The geometry types are used to group Qgis::WkbType in a coarse way.
Definition: qgis.h:255
TextComponent
Text components.
Definition: qgis.h:2380
Base class that can be used for any class that is capable of returning features.
The QgsAbstractLabelProvider class is an interface class.
virtual void drawUnplacedLabel(QgsRenderContext &context, pal::LabelPosition *label) const
Draw an unplaced label.
virtual void stopRender(QgsRenderContext &context)
To be called after rendering is complete.
virtual void drawLabel(QgsRenderContext &context, pal::LabelPosition *label) const =0
Draw this label at the position determined by the labeling engine.
virtual QList< QgsLabelFeature * > labelFeatures(QgsRenderContext &context)=0
Returns list of label features (they are owned by the provider and thus deleted on its destruction)
virtual void drawLabelBackground(QgsRenderContext &context, pal::LabelPosition *label) const
Draw the background for the specified label.
virtual void startRender(QgsRenderContext &context)
To be called before rendering of labels begins.
This class represents a coordinate reference system (CRS).
The feature class encapsulates a single feature including its unique ID, geometry and a list of field...
Definition: qgsfeature.h:56
Container of fields for a vector layer.
Definition: qgsfields.h:45
A geometry is the spatial representation of a feature.
Definition: qgsgeometry.h:162
Base class for all map layer types.
Definition: qgsmaplayer.h:75
Contains settings for how a map layer will be labeled.
Contains information about the context of a rendering operation.
Abstract base class for all rendered symbols.
Definition: qgssymbol.h:94
The QgsVectorLayerLabelProvider class implements a label provider for vector layers.
QgsCoordinateReferenceSystem mCrs
Layer's CRS.
QList< QgsLabelFeature * > mLabels
List of generated.
Qgis::GeometryType mLayerGeometryType
Geometry type of layer.
QgsPalLayerSettings mSettings
Layer's labeling configuration.
std::unique_ptr< QgsAbstractFeatureSource > mSource
Layer's feature source.
Represents a vector layer which manages a vector based data sets.
Implementation class for QgsVectorTileBasicLabeling.
LabelPosition is a candidate feature label position.
Definition: labelposition.h:56
QList< QgsSymbol * > QgsSymbolList
Definition: qgsrenderer.h:44
const QgsCoordinateReferenceSystem & crs