QGIS API Documentation  3.17.0-Master (ca637cfeb2)
qgsalgorithmsumlinelength.h
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1 /***************************************************************************
2  qgsalgorithmsumlinelength.h
3  ---------------------
4  begin : November 2019
5  copyright : (C) 2019 by Alexander Bruy
6  email : alexander dot bruy at gmail dot com
7  ***************************************************************************/
8 
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  ***************************************************************************/
17 
18 #ifndef QGSALGORITHMSUMLINELENGTH_H
19 #define QGSALGORITHMSUMLINELENGTH_H
20 
21 #define SIP_NO_FILE
22 
23 #include "qgis.h"
24 #include "qgsprocessingalgorithm.h"
25 
27 
31 class QgsSumLineLengthAlgorithm : public QgsProcessingFeatureBasedAlgorithm
32 {
33 
34  public:
35 
36  QgsSumLineLengthAlgorithm() = default;
37  QString name() const override;
38  QString displayName() const override;
39  QStringList tags() const override;
40  QString svgIconPath() const override;
41  QIcon icon() const override;
42  QString group() const override;
43  QString groupId() const override;
44  QString shortHelpString() const override;
45  QgsSumLineLengthAlgorithm *createInstance() const override SIP_FACTORY;
46  void initParameters( const QVariantMap &configuration = QVariantMap() ) override;
47  QList<int> inputLayerTypes() const override;
50 
51 
52  protected:
53  QString inputParameterName() const override;
54  QString inputParameterDescription() const override;
55  QString outputName() const override;
56  bool prepareAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback *feedback ) override;
57  QgsFeatureList processFeature( const QgsFeature &feature, QgsProcessingContext &context, QgsProcessingFeedback *feedback ) override;
58  QgsFields outputFields( const QgsFields &inputFields ) const override;
59 
60  private:
61 
62  QString mLengthFieldName;
63  QString mCountFieldName;
64  mutable int mLengthFieldIndex = -1;
65  mutable int mCountFieldIndex = -1;
66  mutable QgsFields mFields;
67  mutable QgsCoordinateReferenceSystem mCrs;
68  mutable QgsDistanceArea mDa;
69  QgsCoordinateTransformContext mTransformContext;
70  std::unique_ptr< QgsProcessingFeatureSource > mLinesSource;
71 };
72 
74 
75 #endif // QGSALGORITHMSUMLINELENGTH_H
virtual QString outputName() const =0
Returns the translated, user visible name for any layers created by this algorithm.
virtual QgsFields outputFields(const QgsFields &inputFields) const
Maps the input source fields (inputFields) to corresponding output fields generated by the algorithm...
virtual bool prepareAlgorithm(const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback *feedback) SIP_THROW(QgsProcessingException)
Prepares the algorithm to run using the specified parameters.
virtual QIcon icon() const
Returns an icon for the algorithm.
Base class for providing feedback from a processing algorithm.
virtual QgsFeatureList processFeature(const QgsFeature &feature, QgsProcessingContext &context, QgsProcessingFeedback *feedback) SIP_THROW(QgsProcessingException)=0
Processes an individual input feature from the source.
QList< QgsFeature > QgsFeatureList
Definition: qgsfeature.h:583
virtual QString name() const =0
Returns the algorithm name, used for identifying the algorithm.
virtual QString group() const
Returns the name of the group this algorithm belongs to.
virtual QString inputParameterName() const
Returns the name of the parameter corresponding to the input layer.
Container of fields for a vector layer.
Definition: qgsfields.h:44
virtual QStringList tags() const
Returns a list of tags which relate to the algorithm, and are used to assist users in searching for s...
The feature class encapsulates a single feature including its id, geometry and a list of field/values...
Definition: qgsfeature.h:55
virtual QList< int > inputLayerTypes() const
Returns the valid input layer types for the source layer for this algorithm.
virtual QString shortHelpString() const
Returns a localised short helper string for the algorithm.
#define SIP_FACTORY
Definition: qgis_sip.h:76
Contains information about the context in which a coordinate transform is executed.
virtual QgsProcessingAlgorithm * createInstance() const =0
Creates a new instance of the algorithm class.
A general purpose distance and area calculator, capable of performing ellipsoid based calculations...
virtual QString displayName() const =0
Returns the translated algorithm name, which should be used for any user-visible display of the algor...
This class represents a coordinate reference system (CRS).
SourceType
Data source types enum.
Definition: qgsprocessing.h:44
virtual void initParameters(const QVariantMap &configuration=QVariantMap())
Initializes any extra parameters added by the algorithm subclass.
virtual QString inputParameterDescription() const
Returns the translated description of the parameter corresponding to the input layer.
virtual QString groupId() const
Returns the unique ID of the group this algorithm belongs to.
An abstract QgsProcessingAlgorithm base class for processing algorithms which operate "feature-by-fea...
Contains information about the context in which a processing algorithm is executed.
virtual QgsCoordinateReferenceSystem outputCrs(const QgsCoordinateReferenceSystem &inputCrs) const
Maps the input source coordinate reference system (inputCrs) to a corresponding output CRS generated ...
virtual QgsProcessing::SourceType outputLayerType() const
Returns the layer type for layers generated by this algorithm, if this is possible to determine in ad...
virtual QString svgIconPath() const
Returns a path to an SVG version of the algorithm&#39;s icon.