QGIS API Documentation  3.23.0-Master (eb871beae0)
qgsvectorlayerfeaturecounter.h
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1 /***************************************************************************
2  qgsvectorlayerfeaturecounter.h
3  ---------------------
4  begin : May 2017
5  copyright : (C) 2017 by Matthias Kuhn
6  email : matthias at opengis dot ch
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 #ifndef QGSVECTORLAYERFEATURECOUNTER_H
16 #define QGSVECTORLAYERFEATURECOUNTER_H
17 
19 #include "qgsrenderer.h"
20 #include "qgstaskmanager.h"
21 #include "qgsfeatureid.h"
22 
33 class CORE_EXPORT QgsVectorLayerFeatureCounter : public QgsTask
34 {
35  Q_OBJECT
36 
37  public:
38 
45  QgsVectorLayerFeatureCounter( QgsVectorLayer *layer, const QgsExpressionContext &context = QgsExpressionContext(), bool storeSymbolFids = false );
47 
51  bool run() override;
52 
53  void cancel() override;
54 
61  QHash<QString, long long> symbolFeatureCountMap() const SIP_SKIP;
62 
67  long long featureCount( const QString &legendKey ) const;
68 
77  QHash<QString, QgsFeatureIds> symbolFeatureIdMap() const SIP_SKIP;
78 
85  QgsFeatureIds featureIds( const QString &symbolkey ) const;
86 
87  signals:
88 
92  void symbolsCounted();
93 
94  private:
96  std::unique_ptr<QgsFeatureRenderer> mRenderer;
97  QgsExpressionContext mExpressionContext;
98  QHash<QString, long long> mSymbolFeatureCountMap;
99  QHash<QString, QgsFeatureIds> mSymbolFeatureIdMap;
100  std::unique_ptr< QgsFeedback > mFeedback;
101  bool mWithFids = false;
102  long mFeatureCount = 0;
103 
104 };
105 
106 #endif // QGSVECTORLAYERFEATURECOUNTER_H
Expression contexts are used to encapsulate the parameters around which a QgsExpression should be eva...
Base class for feedback objects to be used for cancellation of something running in a worker thread.
Definition: qgsfeedback.h:45
Abstract base class for long running background tasks.
virtual bool run()=0
Performs the task's operation.
virtual void cancel()
Notifies the task that it should terminate.
Counts the features in a QgsVectorLayer in task.
~QgsVectorLayerFeatureCounter() override
Partial snapshot of vector layer's state (only the members necessary for access to features)
Represents a vector layer which manages a vector based data sets.
std::unique_ptr< GEOSGeometry, GeosDeleter > unique_ptr
Scoped GEOS pointer.
Definition: qgsgeos.h:79
#define SIP_SKIP
Definition: qgis_sip.h:126
QSet< QgsFeatureId > QgsFeatureIds
Definition: qgsfeatureid.h:37