QGIS API Documentation  3.6.0-Noosa (5873452)
qgsalgorithmboundary.cpp
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1 /***************************************************************************
2  qgsalgorithmboundary.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 
18 #include "qgsalgorithmboundary.h"
19 #include "qgsvectorlayer.h"
20 
22 
23 QString QgsBoundaryAlgorithm::name() const
24 {
25  return QStringLiteral( "boundary" );
26 }
27 
28 QString QgsBoundaryAlgorithm::displayName() const
29 {
30  return QObject::tr( "Boundary" );
31 }
32 
33 QStringList QgsBoundaryAlgorithm::tags() const
34 {
35  return QObject::tr( "boundary,ring,border,exterior" ).split( ',' );
36 }
37 
38 QString QgsBoundaryAlgorithm::group() const
39 {
40  return QObject::tr( "Vector geometry" );
41 }
42 
43 QString QgsBoundaryAlgorithm::groupId() const
44 {
45  return QStringLiteral( "vectorgeometry" );
46 }
47 
48 QString QgsBoundaryAlgorithm::outputName() const
49 {
50  return QObject::tr( "Boundary" );
51 }
52 
53 QString QgsBoundaryAlgorithm::shortHelpString() const
54 {
55  return QObject::tr( "Returns the closure of the combinatorial boundary of the input geometries (ie the "
56  "topological boundary of the geometry). For instance, a polygon geometry will have a "
57  "boundary consisting of the linestrings for each ring in the polygon. Only valid for "
58  "polygon or line layers." );
59 }
60 
61 QList<int> QgsBoundaryAlgorithm::inputLayerTypes() const
62 {
64 }
65 
66 bool QgsBoundaryAlgorithm::supportInPlaceEdit( const QgsMapLayer * ) const
67 {
68  return false;
69 }
70 
71 QgsBoundaryAlgorithm *QgsBoundaryAlgorithm::createInstance() const
72 {
73  return new QgsBoundaryAlgorithm();
74 }
75 
76 QgsWkbTypes::Type QgsBoundaryAlgorithm::outputWkbType( QgsWkbTypes::Type inputWkbType ) const
77 {
79  switch ( QgsWkbTypes::geometryType( inputWkbType ) )
80  {
82  outputWkb = QgsWkbTypes::MultiPoint;
83  break;
84 
86  outputWkb = QgsWkbTypes::MultiLineString;
87  break;
88 
92  outputWkb = QgsWkbTypes::NoGeometry;
93  break;
94  }
95 
96  if ( QgsWkbTypes::hasZ( inputWkbType ) )
97  outputWkb = QgsWkbTypes::addZ( outputWkb );
98  if ( QgsWkbTypes::hasM( inputWkbType ) )
99  outputWkb = QgsWkbTypes::addM( outputWkb );
100 
101  return outputWkb;
102 }
103 
104 QgsFeatureList QgsBoundaryAlgorithm::processFeature( const QgsFeature &feature, QgsProcessingContext &, QgsProcessingFeedback *feedback )
105 {
106  QgsFeature outFeature = feature;
107 
108  if ( feature.hasGeometry() )
109  {
110  QgsGeometry inputGeometry = feature.geometry();
111  QgsGeometry outputGeometry = QgsGeometry( inputGeometry.constGet()->boundary() );
112  if ( outputGeometry.isNull() )
113  {
114  feedback->reportError( QObject::tr( "No boundary for feature %1 (possibly a closed linestring?)'" ).arg( feature.id() ) );
115  outFeature.clearGeometry();
116  }
117  else
118  {
119  outFeature.setGeometry( outputGeometry );
120  }
121  }
122  return QgsFeatureList() << outFeature;
123 }
124 
QgsFeatureId id
Definition: qgsfeature.h:64
Base class for all map layer types.
Definition: qgsmaplayer.h:64
Base class for providing feedback from a processing algorithm.
QList< QgsFeature > QgsFeatureList
Definition: qgsfeature.h:571
A geometry is the spatial representation of a feature.
Definition: qgsgeometry.h:106
virtual QgsAbstractGeometry * boundary() const =0
Returns the closure of the combinatorial boundary of the geometry (ie the topological boundary of the...
The feature class encapsulates a single feature including its id, geometry and a list of field/values...
Definition: qgsfeature.h:55
bool hasGeometry() const
Returns true if the feature has an associated geometry.
Definition: qgsfeature.cpp:197
static bool hasZ(Type type)
Tests whether a WKB type contains the z-dimension.
Definition: qgswkbtypes.h:770
Type
The WKB type describes the number of dimensions a geometry has.
Definition: qgswkbtypes.h:68
static Type addM(Type type)
Adds the m dimension to a WKB type and returns the new type.
Definition: qgswkbtypes.h:891
static GeometryType geometryType(Type type)
Returns the geometry type for a WKB type, e.g., both MultiPolygon and CurvePolygon would have a Polyg...
Definition: qgswkbtypes.h:665
static Type addZ(Type type)
Adds the z dimension to a WKB type and returns the new type.
Definition: qgswkbtypes.h:866
Vector polygon layers.
Definition: qgsprocessing.h:50
const QgsAbstractGeometry * constGet() const
Returns a non-modifiable (const) reference to the underlying abstract geometry primitive.
void clearGeometry()
Removes any geometry associated with the feature.
Definition: qgsfeature.cpp:151
Vector line layers.
Definition: qgsprocessing.h:49
void setGeometry(const QgsGeometry &geometry)
Set the feature&#39;s geometry.
Definition: qgsfeature.cpp:137
static bool hasM(Type type)
Tests whether a WKB type contains m values.
Definition: qgswkbtypes.h:820
QgsGeometry geometry
Definition: qgsfeature.h:67
Contains information about the context in which a processing algorithm is executed.
virtual void reportError(const QString &error, bool fatalError=false)
Reports that the algorithm encountered an error while executing.