QGIS API Documentation 3.39.0-Master (67e056379ed)
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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
66QgsPointOnSurfaceAlgorithm *QgsPointOnSurfaceAlgorithm::createInstance() const
67{
68 return new QgsPointOnSurfaceAlgorithm();
69}
70
71void QgsPointOnSurfaceAlgorithm::initParameters( const QVariantMap & )
72{
73 std::unique_ptr< QgsProcessingParameterBoolean> allParts = std::make_unique< QgsProcessingParameterBoolean >(
74 QStringLiteral( "ALL_PARTS" ),
75 QObject::tr( "Create point on surface for each part" ),
76 false );
77 allParts->setIsDynamic( true );
78 allParts->setDynamicPropertyDefinition( QgsPropertyDefinition( QStringLiteral( "All parts" ), QObject::tr( "Create point on surface for each part" ), QgsPropertyDefinition::Boolean ) );
79 allParts->setDynamicLayerParameterName( QStringLiteral( "INPUT" ) );
80 addParameter( allParts.release() );
81}
82
83bool QgsPointOnSurfaceAlgorithm::prepareAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback * )
84{
85 mAllParts = parameterAsBoolean( parameters, QStringLiteral( "ALL_PARTS" ), context );
86 mDynamicAllParts = QgsProcessingParameters::isDynamic( parameters, QStringLiteral( "ALL_PARTS" ) );
87 if ( mDynamicAllParts )
88 mAllPartsProperty = parameters.value( QStringLiteral( "ALL_PARTS" ) ).value< QgsProperty >();
89
90 return true;
91}
92
93QgsFeatureList QgsPointOnSurfaceAlgorithm::processFeature( const QgsFeature &f, QgsProcessingContext &context, QgsProcessingFeedback *feedback )
94{
95 QgsFeatureList list;
96 QgsFeature feature = f;
97 if ( feature.hasGeometry() && !feature.geometry().isEmpty() )
98 {
99 const QgsGeometry geom = feature.geometry();
100
101 bool allParts = mAllParts;
102 if ( mDynamicAllParts )
103 allParts = mAllPartsProperty.valueAsBool( context.expressionContext(), allParts );
104
105 if ( allParts && geom.isMultipart() )
106 {
107 const QgsGeometryCollection *geomCollection = static_cast<const QgsGeometryCollection *>( geom.constGet() );
108
109 const int partCount = geomCollection->partCount();
110 list.reserve( partCount );
111 for ( int i = 0; i < partCount; ++i )
112 {
113 const QgsGeometry partGeometry( geomCollection->geometryN( i )->clone() );
114 const QgsGeometry outputGeometry = partGeometry.pointOnSurface();
115 if ( outputGeometry.isNull() )
116 {
117 feedback->reportError( QObject::tr( "Error calculating point on surface for feature %1 part %2: %3" ).arg( feature.id() ).arg( i ).arg( outputGeometry.lastError() ) );
118 }
119 feature.setGeometry( outputGeometry );
120 list << feature;
121 }
122 }
123 else
124 {
125 const QgsGeometry outputGeometry = feature.geometry().pointOnSurface();
126 if ( outputGeometry.isNull() )
127 {
128 feedback->reportError( QObject::tr( "Error calculating point on surface for feature %1: %2" ).arg( feature.id() ).arg( outputGeometry.lastError() ) );
129 }
130 feature.setGeometry( outputGeometry );
131 list << feature;
132 }
133 }
134 else
135 {
136 list << feature;
137 }
138 return list;
139}
140
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