qgsalgorithmorientedminimumboundingbox.cpp

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/***************************************************************************
                         qgsalgorithmorientedminimumboundingbox.cpp
                         ---------------------
    begin                : April 2017
    copyright            : (C) 2017 by Nyall Dawson
    email                : nyall dot dawson 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 "qgsalgorithmorientedminimumboundingbox.h"
#include "qgsvectorlayer.h"
 
 
QString QgsOrientedMinimumBoundingBoxAlgorithm::name() const
{
  return QStringLiteral( "orientedminimumboundingbox" );
}
 
QString QgsOrientedMinimumBoundingBoxAlgorithm::displayName() const
{
  return QObject::tr( "Oriented minimum bounding box" );
}
 
QStringList QgsOrientedMinimumBoundingBoxAlgorithm::tags() const
{
  return QObject::tr( "bounding,boxes,envelope,rectangle,extent,oriented,angle" ).split( ',' );
}
 
QString QgsOrientedMinimumBoundingBoxAlgorithm::group() const
{
  return QObject::tr( "Vector geometry" );
}
 
QString QgsOrientedMinimumBoundingBoxAlgorithm::groupId() const
{
  return QStringLiteral( "vectorgeometry" );
}
 
QString QgsOrientedMinimumBoundingBoxAlgorithm::outputName() const
{
  return QObject::tr( "Bounding boxes" );
}
 
Qgis::WkbType QgsOrientedMinimumBoundingBoxAlgorithm::outputWkbType( Qgis::WkbType ) const
{
  return Qgis::WkbType::Polygon;
}
 
QString QgsOrientedMinimumBoundingBoxAlgorithm::shortHelpString() const
{
  return QObject::tr( "This algorithm calculates the minimum area rotated rectangle which covers each feature in an input layer." ) +
         QStringLiteral( "\n\n" ) +
         QObject::tr( "See the 'Minimum bounding geometry' algorithm for a oriented bounding box calculation which covers the whole layer or grouped subsets of features." );
}
 
QgsOrientedMinimumBoundingBoxAlgorithm *QgsOrientedMinimumBoundingBoxAlgorithm::createInstance() const
{
  return new QgsOrientedMinimumBoundingBoxAlgorithm();
}
 
bool QgsOrientedMinimumBoundingBoxAlgorithm::supportInPlaceEdit( const QgsMapLayer *l ) const
{
  const QgsVectorLayer *layer = qobject_cast< const QgsVectorLayer * >( l );
  if ( !layer )
    return false;
 
  if ( ! QgsProcessingFeatureBasedAlgorithm::supportInPlaceEdit( layer ) )
    return false;
  // Polygons only
  return layer->wkbType() == Qgis::WkbType::Polygon || layer->wkbType() == Qgis::WkbType::MultiPolygon;
}
 
QgsFields QgsOrientedMinimumBoundingBoxAlgorithm::outputFields( const QgsFields &inputFields ) const
{
  QgsFields fields = inputFields;
  fields.append( QgsField( QStringLiteral( "width" ), QMetaType::Type::Double, QString(), 20, 6 ) );
  fields.append( QgsField( QStringLiteral( "height" ), QMetaType::Type::Double, QString(), 20, 6 ) );
  fields.append( QgsField( QStringLiteral( "angle" ), QMetaType::Type::Double, QString(), 20, 6 ) );
  fields.append( QgsField( QStringLiteral( "area" ), QMetaType::Type::Double, QString(), 20, 6 ) );
  fields.append( QgsField( QStringLiteral( "perimeter" ), QMetaType::Type::Double, QString(), 20, 6 ) );
  return fields;
}
 
QgsFeatureList QgsOrientedMinimumBoundingBoxAlgorithm::processFeature( const QgsFeature &feature, QgsProcessingContext &, QgsProcessingFeedback * )
{
  QgsFeature f = feature;
  if ( f.hasGeometry() )
  {
    double area = 0;
    double angle = 0;
    double width = 0;
    double height = 0;
    const QgsGeometry outputGeometry = f.geometry().orientedMinimumBoundingBox( area, angle, width, height );
    f.setGeometry( outputGeometry );
    QgsAttributes attrs = f.attributes();
    attrs << width
          << height
          << angle
          << area
          << 2 * width + 2 * height;
    f.setAttributes( attrs );
  }
  else
  {
    QgsAttributes attrs = f.attributes();
    attrs << QVariant()
          << QVariant()
          << QVariant()
          << QVariant()
          << QVariant();
    f.setAttributes( attrs );
  }
  return QgsFeatureList() << f;
}