[processing] make extract vertices feature-based

qgis · Dec 12, 2019 · 8bc571c · 8bc571c
1 parent 61032f0
commit 8bc571c
Show file tree

Hide file tree

Showing 2 changed files with 81 additions and 77 deletions.
diff --git a/src/analysis/processing/qgsalgorithmextractvertices.cpp b/src/analysis/processing/qgsalgorithmextractvertices.cpp
@@ -54,104 +54,103 @@ QString QgsExtractVerticesAlgorithm::shortHelpString() const
          QObject::tr( "Additional fields are added to the point indicating the vertex index (beginning at 0), the vertex’s part and its index within the part (as well as its ring for polygons), distance along original geometry and bisector angle of vertex for original geometry." );
 }
 
+QString QgsExtractVerticesAlgorithm::outputName() const
+{
+  return QObject::tr( "Vertices" );
+}
+
 QgsExtractVerticesAlgorithm *QgsExtractVerticesAlgorithm::createInstance() const
 {
   return new QgsExtractVerticesAlgorithm();
 }
 
-void QgsExtractVerticesAlgorithm::initAlgorithm( const QVariantMap & )
+QgsProcessing::SourceType QgsExtractVerticesAlgorithm::outputLayerType() const
 {
-  addParameter( new QgsProcessingParameterFeatureSource( QStringLiteral( "INPUT" ), QObject::tr( "Input layer" ) ) );
-
-  addParameter( new QgsProcessingParameterFeatureSink( QStringLiteral( "OUTPUT" ), QObject::tr( "Vertices" ) ) );
+  return QgsProcessing::TypeVectorPoint;
 }
 
-QVariantMap QgsExtractVerticesAlgorithm::processAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback *feedback )
+QgsFields QgsExtractVerticesAlgorithm::outputFields( const QgsFields &inputFields ) const
 {
-  std::unique_ptr< QgsProcessingFeatureSource > featureSource( parameterAsSource( parameters, QStringLiteral( "INPUT" ), context ) );
-  if ( !featureSource )
-    throw QgsProcessingException( invalidSourceError( parameters, QStringLiteral( "INPUT" ) ) );
+  QgsFields outputFields = inputFields;
+  outputFields.append( QgsField( QStringLiteral( "vertex_pos" ), QVariant::Int ) );
+  outputFields.append( QgsField( QStringLiteral( "vertex_index" ), QVariant::Int ) );
+  outputFields.append( QgsField( QStringLiteral( "vertex_part" ), QVariant::Int ) );
+  if ( mGeometryType == QgsWkbTypes::PolygonGeometry )
+  {
+    outputFields.append( QgsField( QStringLiteral( "vertex_part_ring" ), QVariant::Int ) );
+  }
+  outputFields.append( QgsField( QStringLiteral( "vertex_part_index" ), QVariant::Int ) );
+  outputFields.append( QgsField( QStringLiteral( "distance" ), QVariant::Double ) );
+  outputFields.append( QgsField( QStringLiteral( "angle" ), QVariant::Double ) );
 
+  return outputFields;
+}
+
+QgsWkbTypes::Type QgsExtractVerticesAlgorithm::outputWkbType( QgsWkbTypes::Type inputWkbType ) const
+{
   QgsWkbTypes::Type outputWkbType = QgsWkbTypes::Point;
-  if ( QgsWkbTypes::hasM( featureSource->wkbType() ) )
+  if ( QgsWkbTypes::hasM( inputWkbType ) )
   {
     outputWkbType = QgsWkbTypes::addM( outputWkbType );
   }
-  if ( QgsWkbTypes::hasZ( featureSource->wkbType() ) )
+  if ( QgsWkbTypes::hasZ( inputWkbType ) )
   {
     outputWkbType = QgsWkbTypes::addZ( outputWkbType );
   }
 
-  QgsFields outputFields = featureSource->fields();
-  outputFields.append( QgsField( QStringLiteral( "vertex_index" ), QVariant::Int, QString(), 10, 0 ) );
-  outputFields.append( QgsField( QStringLiteral( "vertex_part" ), QVariant::Int, QString(), 10, 0 ) );
-  if ( QgsWkbTypes::geometryType( featureSource->wkbType() ) == QgsWkbTypes::PolygonGeometry )
+  return outputWkbType;
+}
+
+bool QgsExtractVerticesAlgorithm::prepareAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback * )
+{
+  std::unique_ptr< QgsProcessingFeatureSource > source( parameterAsSource( parameters, QStringLiteral( "INPUT" ), context ) );
+  mGeometryType = QgsWkbTypes::geometryType( source->wkbType() );
+  return true;
+}
+
+QgsFeatureList QgsExtractVerticesAlgorithm::processFeature( const QgsFeature &feature, QgsProcessingContext &, QgsProcessingFeedback * )
+{
+  QgsFeatureList outputFeatures;
+
+  QgsFeature f = feature;
+  QgsGeometry inputGeom = f.geometry();
+  if ( inputGeom.isNull() )
   {
-    outputFields.append( QgsField( QStringLiteral( "vertex_part_ring" ), QVariant::Int, QString(), 10, 0 ) );
+    outputFeatures << f;
   }
-  outputFields.append( QgsField( QStringLiteral( "vertex_part_index" ), QVariant::Int, QString(), 10, 0 ) );
-  outputFields.append( QgsField( QStringLiteral( "distance" ), QVariant::Double, QString(), 20, 14 ) );
-  outputFields.append( QgsField( QStringLiteral( "angle" ), QVariant::Double, QString(), 20, 14 ) );
-
-  QString dest;
-  std::unique_ptr< QgsFeatureSink > sink( parameterAsSink( parameters, QStringLiteral( "OUTPUT" ), context, dest, outputFields, outputWkbType, featureSource->sourceCrs(), QgsFeatureSink::RegeneratePrimaryKey ) );
-  if ( !sink )
-    throw QgsProcessingException( invalidSinkError( parameters, QStringLiteral( "OUTPUT" ) ) );
-
-  double step = featureSource->featureCount() > 0 ? 100.0 / featureSource->featureCount() : 1;
-  QgsFeatureIterator fi = featureSource->getFeatures( QgsFeatureRequest(), QgsProcessingFeatureSource::FlagSkipGeometryValidityChecks );
-  QgsFeature f;
-  int i = -1;
-  while ( fi.nextFeature( f ) )
+  else
   {
-    i++;
-    if ( feedback->isCanceled() )
-    {
-      break;
-    }
-
-    QgsGeometry inputGeom = f.geometry();
-    if ( inputGeom.isNull() )
-    {
-      sink->addFeature( f, QgsFeatureSink::FastInsert );
-    }
-    else
+    QgsAbstractGeometry::vertex_iterator vi = inputGeom.constGet()->vertices_begin();
+    double cumulativeDistance = 0.0;
+    int vertexPos = 0;
+    while ( vi != inputGeom.constGet()->vertices_end() )
     {
-      QgsAbstractGeometry::vertex_iterator vi = inputGeom.constGet()->vertices_begin();
-      double cumulativeDistance = 0.0;
-      int vertexPos = 0;
-      while ( vi != inputGeom.constGet()->vertices_end() )
+      QgsVertexId vertexId = vi.vertexId();
+      double angle = inputGeom.constGet()->vertexAngle( vertexId ) * 180 / M_PI;
+      QgsAttributes attrs = f.attributes();
+      attrs << vertexPos
+            << vertexId.part;
+      if ( mGeometryType == QgsWkbTypes::PolygonGeometry )
       {
-        QgsVertexId vertexId = vi.vertexId();
-        double angle = inputGeom.constGet()->vertexAngle( vertexId ) * 180 / M_PI;
-        QgsAttributes attrs = f.attributes();
-        attrs << vertexPos
-              << vertexId.part;
-        if ( QgsWkbTypes::geometryType( featureSource->wkbType() ) == QgsWkbTypes::PolygonGeometry )
-        {
-          attrs << vertexId.ring;
-        }
-        attrs << vertexId.vertex
-              << cumulativeDistance
-              << angle;
-        QgsFeature outputFeature = QgsFeature();
-        outputFeature.setAttributes( attrs );
-        outputFeature.setGeometry( QgsGeometry( ( *vi ).clone() ) );
-        sink->addFeature( outputFeature, QgsFeatureSink::FastInsert );
-        vi++;
-        vertexPos++;
-
-        // calculate distance to next vertex
-        double distanceToNext = inputGeom.constGet()->segmentLength( vertexId );
-        cumulativeDistance += distanceToNext;
+        attrs << vertexId.ring;
       }
+      attrs << vertexId.vertex
+            << cumulativeDistance
+            << angle;
+      QgsFeature outputFeature = QgsFeature();
+      outputFeature.setAttributes( attrs );
+      outputFeature.setGeometry( QgsGeometry( ( *vi ).clone() ) );
+      outputFeatures << outputFeature;
+      vi++;
+      vertexPos++;
+
+      // calculate distance to next vertex
+      double distanceToNext = inputGeom.constGet()->segmentLength( vertexId );
+      cumulativeDistance += distanceToNext;
     }
-    feedback->setProgress( i * step );
   }
 
-  QVariantMap outputs;
-  outputs.insert( QStringLiteral( "OUTPUT" ), dest );
-  return outputs;
+  return outputFeatures;
 }
 
 ///@endcond
diff --git a/src/analysis/processing/qgsalgorithmextractvertices.h b/src/analysis/processing/qgsalgorithmextractvertices.h
@@ -29,15 +29,14 @@
 /**
  * Native extract nodes algorithm.
  */
-class QgsExtractVerticesAlgorithm : public QgsProcessingAlgorithm
+class QgsExtractVerticesAlgorithm : public QgsProcessingFeatureBasedAlgorithm
 {
 
   public:
 
     QgsExtractVerticesAlgorithm() = default;
     QIcon icon() const override { return QgsApplication::getThemeIcon( QStringLiteral( "/algorithms/mAlgorithmExtractVertices.svg" ) ); }
     QString svgIconPath() const override { return QgsApplication::iconPath( QStringLiteral( "/algorithms/mAlgorithmExtractVertices.svg" ) ); }
-    void initAlgorithm( const QVariantMap &configuration = QVariantMap() ) override;
     QString name() const override;
     QString displayName() const override;
     QStringList tags() const override;
@@ -47,13 +46,19 @@ class QgsExtractVerticesAlgorithm : public QgsProcessingAlgorithm
     QgsExtractVerticesAlgorithm *createInstance() const override SIP_FACTORY;
 
   protected:
-    QVariantMap processAlgorithm( const QVariantMap &parameters,
-                                  QgsProcessingContext &context, QgsProcessingFeedback *feedback ) override;
 
+    QString outputName() const override;
+    QgsFields outputFields( const QgsFields &inputFields ) const override;
+    QgsProcessing::SourceType outputLayerType() const override;
+    QgsWkbTypes::Type outputWkbType( QgsWkbTypes::Type inputWkbType ) const override;
+
+    bool prepareAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback *feedback ) override;
+    QgsFeatureList processFeature( const QgsFeature &feature,  QgsProcessingContext &context, QgsProcessingFeedback *feedback ) override;
+
+  private:
+    QgsWkbTypes::GeometryType mGeometryType;
 };
 
 ///@endcond PRIVATE
 
 #endif // QGSALGORITHMEXTRACTVERTICES_H
-
-