[processing] port Polygonize algorithm to C++

qgis · May 11, 2020 · b4a52d3 · b4a52d3
1 parent c0e8178
commit b4a52d3
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Showing 6 changed files with 198 additions and 125 deletions.
diff --git a/python/plugins/processing/algs/qgis/Polygonize.py b/python/plugins/processing/algs/qgis/Polygonize.py
diff --git a/python/plugins/processing/algs/qgis/QgisAlgorithmProvider.py b/python/plugins/processing/algs/qgis/QgisAlgorithmProvider.py
@@ -63,7 +63,6 @@
 from .PointsFromLines import PointsFromLines
 from .PointsToPaths import PointsToPaths
 from .PolarPlot import PolarPlot
-from .Polygonize import Polygonize
 from .PostGISExecuteAndLoadSQL import PostGISExecuteAndLoadSQL
 from .RandomExtractWithinSubsets import RandomExtractWithinSubsets
 from .RandomPointsAlongLines import RandomPointsAlongLines
@@ -141,7 +140,6 @@ def getAlgs(self):
                 PointsFromLines(),
                 PointsToPaths(),
                 PolarPlot(),
-                Polygonize(),
                 PostGISExecuteAndLoadSQL(),
                 RandomExtractWithinSubsets(),
                 RandomPointsAlongLines(),

diff --git a/src/analysis/CMakeLists.txt b/src/analysis/CMakeLists.txt
@@ -110,6 +110,7 @@ SET(QGIS_ANALYSIS_SRCS
   processing/qgsalgorithmpointsalonggeometry.cpp
   processing/qgsalgorithmpointslayerfromtable.cpp
   processing/qgsalgorithmpoleofinaccessibility.cpp
+  processing/qgsalgorithmpolygonize.cpp
   processing/qgsalgorithmprojectpointcartesian.cpp
   processing/qgsalgorithmpromotetomultipart.cpp
   processing/qgsalgorithmraiseexception.cpp

diff --git a/src/analysis/processing/qgsalgorithmpolygonize.cpp b/src/analysis/processing/qgsalgorithmpolygonize.cpp
@@ -0,0 +1,141 @@
+/***************************************************************************
+                         qgsalgorithmdpolygonize.cpp
+                         ---------------------
+    begin                : May 2020
+    copyright            : (C) 2020 by Alexander Bruy
+    email                : alexander dot bruy at gmail dot com
+ ***************************************************************************/
+
+/***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#include "qgsalgorithmpolygonize.h"
+#include "qgsgeometrycollection.h"
+
+///@cond PRIVATE
+
+QString QgsPolygonizeAlgorithm::name() const
+{
+  return QStringLiteral( "polygonize" );
+}
+
+QString QgsPolygonizeAlgorithm::displayName() const
+{
+  return QObject::tr( "Polygonize" );
+}
+
+QString QgsPolygonizeAlgorithm::shortHelpString() const
+{
+  return QObject::tr( "Creates a polygon layer from the input lines layer." );
+}
+
+QStringList QgsPolygonizeAlgorithm::tags() const
+{
+  return QObject::tr( "create,lines,polygons,convert" ).split( ',' );
+}
+
+QString QgsPolygonizeAlgorithm::group() const
+{
+  return QObject::tr( "Vector geometry" );
+}
+
+QString QgsPolygonizeAlgorithm::groupId() const
+{
+  return QStringLiteral( "vectorgeometry" );
+}
+
+void QgsPolygonizeAlgorithm::initAlgorithm( const QVariantMap & )
+{
+  addParameter( new QgsProcessingParameterFeatureSource( QStringLiteral( "INPUT" ),
+                QObject::tr( "Input layer" ), QList< int >() << QgsProcessing::TypeVectorLine ) );
+  addParameter( new QgsProcessingParameterBoolean( QStringLiteral( "KEEP_FIELDS" ),
+                QObject::tr( "Keep fields from the input layer" ), false, true ) );
+  addParameter( new QgsProcessingParameterFeatureSink( QStringLiteral( "OUTPUT" ),
+                QObject::tr( "Polygons" ), QgsProcessing::TypeVectorPolygon ) );
+  addOutput( new QgsProcessingOutputNumber( QStringLiteral( "NUM_POLYGONS" ), QObject::tr( "Number of polygons" ) ) );
+}
+
+QgsPolygonizeAlgorithm *QgsPolygonizeAlgorithm::createInstance() const
+{
+  return new QgsPolygonizeAlgorithm();
+}
+
+QVariantMap QgsPolygonizeAlgorithm::processAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback *feedback )
+{
+  std::unique_ptr< QgsProcessingFeatureSource > source( parameterAsSource( parameters, QStringLiteral( "INPUT" ), context ) );
+  if ( !source )
+    throw QgsProcessingException( invalidSourceError( parameters, QStringLiteral( "INPUT" ) ) );
+
+  QgsFields fields = QgsFields();
+  if ( parameterAsBoolean( parameters, QStringLiteral( "KEEP_FIELDS" ), context ) )
+    fields = source->fields();
+
+  QString dest;
+  std::unique_ptr< QgsFeatureSink > sink( parameterAsSink( parameters, QStringLiteral( "OUTPUT" ), context, dest, fields, QgsWkbTypes::Polygon, source->sourceCrs() ) );
+  if ( !sink )
+    throw QgsProcessingException( invalidSinkError( parameters, QStringLiteral( "OUTPUT" ) ) );
+
+  int polygonCount = 0;
+
+  feedback->pushInfo( QObject::tr( "Collecting lines…" ) );
+  int i = 0;
+  double step = source->featureCount() > 0 ? 40.0 / source->featureCount() : 1;
+  QgsFeature f;
+  QgsFeatureIterator features = source->getFeatures( QgsFeatureRequest().setNoAttributes() );
+  QVector<QgsGeometry> linesList;
+  linesList.reserve( source->featureCount() );
+  while ( features.nextFeature( f ) )
+  {
+    if ( feedback->isCanceled() )
+      break;
+
+    if ( f.hasGeometry() )
+      linesList << f.geometry();
+
+    feedback->setProgress( i * step );
+  }
+  feedback->setProgress( 40 );
+
+  feedback->pushInfo( QObject::tr( "Noding lines…" ) );
+  QgsGeometry lines = QgsGeometry::unaryUnion( linesList );
+  if ( feedback->isCanceled() )
+    return QVariantMap();
+  feedback->setProgress( 45 );
+
+  feedback->pushInfo( QObject::tr( "Polygonizing…" ) );
+  QgsGeometry polygons = QgsGeometry::polygonize( QVector< QgsGeometry >() << lines );
+  if ( polygons.isEmpty() )
+    feedback->reportError( QObject::tr( "No polygons were created." ) );
+
+  feedback->setProgress( 50 );
+
+  if ( !polygons.isEmpty() )
+  {
+    const QgsGeometryCollection *collection = qgsgeometry_cast< const QgsGeometryCollection * >( polygons.constGet() );
+    step = collection->numGeometries() > 0 ? 50.0 / collection->numGeometries() : 1;
+    for ( int part = 0; part < collection->numGeometries(); ++part )
+    {
+      if ( feedback->isCanceled() )
+        break;
+
+      QgsFeature outFeat;
+      outFeat.setGeometry( QgsGeometry( collection->geometryN( part )->clone() ) );
+      sink->addFeature( outFeat, QgsFeatureSink::FastInsert );
+      feedback->setProgress( 50 + i * step );
+      polygonCount += 1;
+    }
+  }
+
+  QVariantMap outputs;
+  outputs.insert( QStringLiteral( "OUTPUT" ), dest );
+  outputs.insert( QStringLiteral( "NUM_POLYGONS" ), polygonCount );
+  return outputs;
+}
+
+///@endcond
diff --git a/src/analysis/processing/qgsalgorithmpolygonize.h b/src/analysis/processing/qgsalgorithmpolygonize.h
@@ -0,0 +1,54 @@
+/***************************************************************************
+                         qgsalgorithmpolygonize.h
+                         ---------------------
+    begin                : May 2020
+    copyright            : (C) 2020 by Alexander Bruy
+    email                : alexander dot bruy at gmail dot com
+ ***************************************************************************/
+
+/***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#ifndef QGSALGORITHMPOLYGONIZE_H
+#define QGSALGORITHMPOLYGONIZE_H
+
+#define SIP_NO_FILE
+
+#include "qgis_sip.h"
+#include "qgsprocessingalgorithm.h"
+
+///@cond PRIVATE
+
+/**
+ * Native polygonize algorithm.
+ */
+class QgsPolygonizeAlgorithm : public QgsProcessingAlgorithm
+{
+
+  public:
+
+    QgsPolygonizeAlgorithm() = default;
+    void initAlgorithm( const QVariantMap &configuration = QVariantMap() ) override;
+    QString name() const override;
+    QString displayName() const override;
+    QStringList tags() const override;
+    QString group() const override;
+    QString groupId() const override;
+    QString shortHelpString() const override;
+    QgsPolygonizeAlgorithm *createInstance() const override SIP_FACTORY;
+
+  protected:
+
+    QVariantMap processAlgorithm( const QVariantMap &parameters,
+                                  QgsProcessingContext &context, QgsProcessingFeedback *feedback ) override;
+};
+
+///@endcond PRIVATE
+
+#endif // QGSALGORITHMPOLYGONIZE_H
diff --git a/src/analysis/processing/qgsnativealgorithms.cpp b/src/analysis/processing/qgsnativealgorithms.cpp
@@ -104,6 +104,7 @@
 #include "qgsalgorithmpointsalonggeometry.h"
 #include "qgsalgorithmpointslayerfromtable.h"
 #include "qgsalgorithmpoleofinaccessibility.h"
+#include "qgsalgorithmpolygonize.h"
 #include "qgsalgorithmprojectpointcartesian.h"
 #include "qgsalgorithmpromotetomultipart.h"
 #include "qgsalgorithmraiseexception.h"
@@ -313,6 +314,7 @@ void QgsNativeAlgorithms::loadAlgorithms()
   addAlgorithm( new QgsPointsAlongGeometryAlgorithm() );
   addAlgorithm( new QgsPointsLayerFromTableAlgorithm() );
   addAlgorithm( new QgsPoleOfInaccessibilityAlgorithm() );
+  addAlgorithm( new QgsPolygonizeAlgorithm() );
   addAlgorithm( new QgsProjectPointCartesianAlgorithm() );
   addAlgorithm( new QgsPromoteToMultipartAlgorithm() );
   addAlgorithm( new QgsRaiseExceptionAlgorithm() );