QGIS API Documentation 3.40.0-Bratislava (b56115d8743)
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qgsalgorithmpointonsurface.cpp
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1/***************************************************************************
2 qgsalgorithmpointonsurface.cpp
3 ------------------------
4 begin : March 2018
5 copyright : (C) 2018 by Nyall Dawson
6 email : nyall dot dawson 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
20
22
23QString QgsPointOnSurfaceAlgorithm::name() const
24{
25 return QStringLiteral( "pointonsurface" );
26}
27
28QString QgsPointOnSurfaceAlgorithm::displayName() const
29{
30 return QObject::tr( "Point on surface" );
31}
32
33QStringList QgsPointOnSurfaceAlgorithm::tags() const
34{
35 return QObject::tr( "centroid,inside,within" ).split( ',' );
36}
37
38QString QgsPointOnSurfaceAlgorithm::group() const
39{
40 return QObject::tr( "Vector geometry" );
41}
42
43QString QgsPointOnSurfaceAlgorithm::groupId() const
44{
45 return QStringLiteral( "vectorgeometry" );
46}
47
48QString QgsPointOnSurfaceAlgorithm::outputName() const
49{
50 return QObject::tr( "Point" );
51}
52
53QgsFeatureSink::SinkFlags QgsPointOnSurfaceAlgorithm::sinkFlags() const
54{
55 if ( mAllParts )
57 else
59}
60
61QString QgsPointOnSurfaceAlgorithm::shortHelpString() const
62{
63 return QObject::tr( "Returns a point guaranteed to lie on the surface of a geometry." );
64}
65
66Qgis::ProcessingAlgorithmDocumentationFlags QgsPointOnSurfaceAlgorithm::documentationFlags() const
67{
69}
70
71QgsPointOnSurfaceAlgorithm *QgsPointOnSurfaceAlgorithm::createInstance() const
72{
73 return new QgsPointOnSurfaceAlgorithm();
74}
75
76void QgsPointOnSurfaceAlgorithm::initParameters( const QVariantMap & )
77{
78 std::unique_ptr< QgsProcessingParameterBoolean> allParts = std::make_unique< QgsProcessingParameterBoolean >(
79 QStringLiteral( "ALL_PARTS" ),
80 QObject::tr( "Create point on surface for each part" ),
81 false );
82 allParts->setIsDynamic( true );
83 allParts->setDynamicPropertyDefinition( QgsPropertyDefinition( QStringLiteral( "All parts" ), QObject::tr( "Create point on surface for each part" ), QgsPropertyDefinition::Boolean ) );
84 allParts->setDynamicLayerParameterName( QStringLiteral( "INPUT" ) );
85 addParameter( allParts.release() );
86}
87
88bool QgsPointOnSurfaceAlgorithm::prepareAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback * )
89{
90 mAllParts = parameterAsBoolean( parameters, QStringLiteral( "ALL_PARTS" ), context );
91 mDynamicAllParts = QgsProcessingParameters::isDynamic( parameters, QStringLiteral( "ALL_PARTS" ) );
92 if ( mDynamicAllParts )
93 mAllPartsProperty = parameters.value( QStringLiteral( "ALL_PARTS" ) ).value< QgsProperty >();
94
95 return true;
96}
97
98QgsFeatureList QgsPointOnSurfaceAlgorithm::processFeature( const QgsFeature &f, QgsProcessingContext &context, QgsProcessingFeedback *feedback )
99{
100 QgsFeatureList list;
101 QgsFeature feature = f;
102 if ( feature.hasGeometry() && !feature.geometry().isEmpty() )
103 {
104 const QgsGeometry geom = feature.geometry();
105
106 bool allParts = mAllParts;
107 if ( mDynamicAllParts )
108 allParts = mAllPartsProperty.valueAsBool( context.expressionContext(), allParts );
109
110 if ( allParts && geom.isMultipart() )
111 {
112 const QgsGeometryCollection *geomCollection = static_cast<const QgsGeometryCollection *>( geom.constGet() );
113
114 const int partCount = geomCollection->partCount();
115 list.reserve( partCount );
116 for ( int i = 0; i < partCount; ++i )
117 {
118 const QgsGeometry partGeometry( geomCollection->geometryN( i )->clone() );
119 const QgsGeometry outputGeometry = partGeometry.pointOnSurface();
120 if ( outputGeometry.isNull() )
121 {
122 feedback->reportError( QObject::tr( "Error calculating point on surface for feature %1 part %2: %3" ).arg( feature.id() ).arg( i ).arg( outputGeometry.lastError() ) );
123 }
124 feature.setGeometry( outputGeometry );
125 list << feature;
126 }
127 }
128 else
129 {
130 const QgsGeometry outputGeometry = feature.geometry().pointOnSurface();
131 if ( outputGeometry.isNull() )
132 {
133 feedback->reportError( QObject::tr( "Error calculating point on surface for feature %1: %2" ).arg( feature.id() ).arg( outputGeometry.lastError() ) );
134 }
135 feature.setGeometry( outputGeometry );
136 list << feature;
137 }
138 }
139 else
140 {
141 list << feature;
142 }
143 return list;
144}
145
@ RegeneratesPrimaryKeyInSomeScenarios
Algorithm may drop the existing primary keys or FID values in some scenarios, depending on algorithm ...
QFlags< ProcessingAlgorithmDocumentationFlag > ProcessingAlgorithmDocumentationFlags
Flags describing algorithm behavior for documentation purposes.
Definition qgis.h:3359
virtual QgsAbstractGeometry * clone() const =0
Clones the geometry by performing a deep copy.
QFlags< SinkFlag > SinkFlags
@ RegeneratePrimaryKey
This flag indicates, that a primary key field cannot be guaranteed to be unique and the sink should i...
The feature class encapsulates a single feature including its unique ID, geometry and a list of field...
Definition qgsfeature.h:58
QgsFeatureId id
Definition qgsfeature.h:66
QgsGeometry geometry
Definition qgsfeature.h:69
bool hasGeometry() const
Returns true if the feature has an associated geometry.
void setGeometry(const QgsGeometry &geometry)
Set the feature's geometry.
int partCount() const override
Returns count of parts contained in the geometry.
const QgsAbstractGeometry * geometryN(int n) const
Returns a const reference to a geometry from within the collection.
A geometry is the spatial representation of a feature.
QgsGeometry pointOnSurface() const
Returns a point guaranteed to lie on the surface of a geometry.
QString lastError() const
Returns an error string referring to the last error encountered either when this geometry was created...
const QgsAbstractGeometry * constGet() const
Returns a non-modifiable (const) reference to the underlying abstract geometry primitive.
bool isMultipart() const
Returns true if WKB of the geometry is of WKBMulti* type.
bool isEmpty() const
Returns true if the geometry is empty (eg a linestring with no vertices, or a collection with no geom...
Contains information about the context in which a processing algorithm is executed.
QgsExpressionContext & expressionContext()
Returns the expression context.
virtual QgsFeatureSink::SinkFlags sinkFlags() const
Returns the feature sink flags to be used for the output.
Base class for providing feedback from a processing algorithm.
virtual void reportError(const QString &error, bool fatalError=false)
Reports that the algorithm encountered an error while executing.
static bool isDynamic(const QVariantMap &parameters, const QString &name)
Returns true if the parameter with matching name is a dynamic parameter, and must be evaluated once f...
Definition for a property.
Definition qgsproperty.h:45
@ Boolean
Boolean value.
Definition qgsproperty.h:51
A store for object properties.
QList< QgsFeature > QgsFeatureList