QGIS API Documentation 3.39.0-Master (67e056379ed)
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qgsalgorithmsubdivide.cpp
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1/***************************************************************************
2 qgsalgorithmsubdivide.cpp
3 ---------------------
4 begin : April 2017
5 copyright : (C) 2017 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
19
21
22void QgsSubdivideAlgorithm::initParameters( const QVariantMap & )
23{
24 std::unique_ptr< QgsProcessingParameterNumber> nodes = std::make_unique< QgsProcessingParameterNumber >( QStringLiteral( "MAX_NODES" ), QObject::tr( "Maximum nodes in parts" ), Qgis::ProcessingNumberParameterType::Integer,
25 256, false, 8, 100000 );
26 nodes->setIsDynamic( true );
27 nodes->setDynamicPropertyDefinition( QgsPropertyDefinition( QStringLiteral( "MAX_NODES" ), QObject::tr( "Maximum nodes in parts" ), QgsPropertyDefinition::Integer ) );
28 nodes->setDynamicLayerParameterName( QStringLiteral( "INPUT" ) );
29
30 addParameter( nodes.release() );
31}
32
33QString QgsSubdivideAlgorithm::name() const
34{
35 return QStringLiteral( "subdivide" );
36}
37
38QString QgsSubdivideAlgorithm::displayName() const
39{
40 return QObject::tr( "Subdivide" );
41}
42
43QStringList QgsSubdivideAlgorithm::tags() const
44{
45 return QObject::tr( "subdivide,segmentize,split,tessellate" ).split( ',' );
46}
47
48QString QgsSubdivideAlgorithm::group() const
49{
50 return QObject::tr( "Vector geometry" );
51}
52
53QString QgsSubdivideAlgorithm::groupId() const
54{
55 return QStringLiteral( "vectorgeometry" );
56}
57
58QString QgsSubdivideAlgorithm::shortHelpString() const
59{
60 return QObject::tr( "Subdivides the geometry. The returned geometry will be a collection containing subdivided parts "
61 "from the original geometry, where no part has more then the specified maximum number of nodes.\n\n"
62 "This is useful for dividing a complex geometry into less complex parts, which are better able to be spatially "
63 "indexed and faster to perform further operations such as intersects on. The returned geometry parts may "
64 "not be valid and may contain self-intersections.\n\n"
65 "Curved geometries will be segmentized before subdivision." );
66}
67
68QgsSubdivideAlgorithm *QgsSubdivideAlgorithm::createInstance() const
69{
70 return new QgsSubdivideAlgorithm();
71}
72
73QString QgsSubdivideAlgorithm::outputName() const
74{
75 return QObject::tr( "Subdivided" );
76}
77
78Qgis::WkbType QgsSubdivideAlgorithm::outputWkbType( Qgis::WkbType inputWkbType ) const
79{
80 return QgsWkbTypes::multiType( inputWkbType );
81}
82
83QgsFeatureList QgsSubdivideAlgorithm::processFeature( const QgsFeature &f, QgsProcessingContext &context, QgsProcessingFeedback *feedback )
84{
85 QgsFeature feature = f;
86 if ( feature.hasGeometry() )
87 {
88 int maxNodes = mMaxNodes;
89 if ( mDynamicMaxNodes )
90 maxNodes = mMaxNodesProperty.valueAsDouble( context.expressionContext(), maxNodes );
91
92 feature.setGeometry( feature.geometry().subdivide( maxNodes ) );
93 if ( !feature.hasGeometry() )
94 {
95 feedback->reportError( QObject::tr( "Error calculating subdivision for feature %1" ).arg( feature.id() ) );
96 }
97 }
98 return QgsFeatureList() << feature;
99}
100
101bool QgsSubdivideAlgorithm::prepareAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback * )
102{
103 mMaxNodes = parameterAsInt( parameters, QStringLiteral( "MAX_NODES" ), context );
104 mDynamicMaxNodes = QgsProcessingParameters::isDynamic( parameters, QStringLiteral( "MAX_NODES" ) );
105 if ( mDynamicMaxNodes )
106 mMaxNodesProperty = parameters.value( QStringLiteral( "MAX_NODES" ) ).value< QgsProperty >();
107
108 return true;
109}
110
111
112
114
115
116
WkbType
The WKB type describes the number of dimensions a geometry has.
Definition qgis.h:201
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.
QgsGeometry subdivide(int maxNodes=256, const QgsGeometryParameters &parameters=QgsGeometryParameters()) const
Subdivides the geometry.
Contains information about the context in which a processing algorithm is executed.
QgsExpressionContext & expressionContext()
Returns the expression context.
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
@ Integer
Integer value (including negative values)
Definition qgsproperty.h:52
A store for object properties.
static Qgis::WkbType multiType(Qgis::WkbType type)
Returns the multi type for a WKB type.
QList< QgsFeature > QgsFeatureList