QGIS API Documentation  3.23.0-Master (eb871beae0)
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1 /***************************************************************************
2  qgsalgorithmgeometrybyexpression.h
3  ----------------------
4  begin : November 2019
5  copyright : (C) 2019 by Alexander Bruy
6  email : alexander dot bruy at gmail dot com
7  ***************************************************************************/
9 /***************************************************************************
10  * *
11  * This program is free software; you can redistribute it and/or modify *
12  * it under the terms of the GNU General Public License as published by *
13  * the Free Software Foundation; either version 2 of the License, or *
14  * (at your option) any later version. *
15  * *
16  ***************************************************************************/
21 #define SIP_NO_FILE
23 #include "qgis_sip.h"
24 #include "qgsprocessingalgorithm.h"
25 #include "qgsapplication.h"
32 class QgsGeometryByExpressionAlgorithm : public QgsProcessingFeatureBasedAlgorithm
33 {
35  public:
37  QgsGeometryByExpressionAlgorithm() = default;
38  QIcon icon() const override { return QgsApplication::getThemeIcon( QStringLiteral( "/algorithms/mAlgorithmCentroids.svg" ) ); }
39  QString svgIconPath() const override { return QgsApplication::iconPath( QStringLiteral( "/algorithms/mAlgorithmCentroids.svg" ) ); }
40  QString name() const override;
41  QString displayName() const override;
42  QStringList tags() const override;
43  QString group() const override;
44  QString groupId() const override;
45  QString shortHelpString() const override;
46  QList<int> inputLayerTypes() const override;
47  QgsGeometryByExpressionAlgorithm *createInstance() const override SIP_FACTORY;
48  void initParameters( const QVariantMap &configuration = QVariantMap() ) override;
50  protected:
52  QString outputName() const override;
53  QgsWkbTypes::Type outputWkbType( QgsWkbTypes::Type ) const override;
54  QgsProcessingFeatureSource::Flag sourceFlags() const override;
55  bool prepareAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback *feedback ) override;
56  QgsFeatureList processFeature( const QgsFeature &feature, QgsProcessingContext &context, QgsProcessingFeedback *feedback ) override;
58  private:
60  QgsWkbTypes::Type mWkbType;
61  QgsExpression mExpression;
62  QgsExpressionContext mExpressionContext;
63 };
static QIcon getThemeIcon(const QString &name, const QColor &fillColor=QColor(), const QColor &strokeColor=QColor())
Helper to get a theme icon.
static QString iconPath(const QString &iconFile)
Returns path to the desired icon file.
Expression contexts are used to encapsulate the parameters around which a QgsExpression should be eva...
Class for parsing and evaluation of expressions (formerly called "search strings").
The feature class encapsulates a single feature including its unique ID, geometry and a list of field...
Definition: qgsfeature.h:56
virtual QString group() const
Returns the name of the group this algorithm belongs to.
virtual QString groupId() const
Returns the unique ID of the group this algorithm belongs to.
virtual QIcon icon() const
Returns an icon for the algorithm.
virtual QString shortHelpString() const
Returns a localised short helper string for the algorithm.
virtual QString displayName() const =0
Returns the translated algorithm name, which should be used for any user-visible display of the algor...
virtual QgsProcessingAlgorithm * createInstance() const =0
Creates a new instance of the algorithm class.
virtual QStringList tags() const
Returns a list of tags which relate to the algorithm, and are used to assist users in searching for s...
virtual QString svgIconPath() const
Returns a path to an SVG version of the algorithm's icon.
virtual QString name() const =0
Returns the algorithm name, used for identifying the algorithm.
Contains information about the context in which a processing algorithm is executed.
An abstract QgsProcessingAlgorithm base class for processing algorithms which operate "feature-by-fea...
virtual QList< int > inputLayerTypes() const
Returns the valid input layer types for the source layer for this algorithm.
Flags controlling how QgsProcessingFeatureSource fetches features.
Base class for providing feedback from a processing algorithm.
The WKB type describes the number of dimensions a geometry has.
Definition: qgswkbtypes.h:70
Definition: qgis_sip.h:76
QList< QgsFeature > QgsFeatureList
Definition: qgsfeature.h:834