qgsgeometryselfintersectioncheck.cpp

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/***************************************************************************
    qgsgeometryselfintersectioncheck.cpp
    ---------------------
    begin                : September 2015
    copyright            : (C) 2014 by Sandro Mani / Sourcepole AG
    email                : smani at sourcepole dot ch
 ***************************************************************************
 *                                                                         *
 *   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 "qgsgeometryselfintersectioncheck.h"
 
#include "qgsfeaturepool.h"
#include "qgsgeometrycheckcontext.h"
#include "qgsgeometryengine.h"
#include "qgsgeometryutils.h"
#include "qgslinestring.h"
#include "qgsmultilinestring.h"
#include "qgsmultipolygon.h"
#include "qgspolygon.h"
 
bool QgsGeometrySelfIntersectionCheckError::isEqual( const QgsSingleGeometryCheckError *other ) const
{
  return QgsSingleGeometryCheckError::isEqual( other ) && static_cast<const QgsGeometrySelfIntersectionCheckError *>( other )->intersection().segment1 == intersection().segment1 && static_cast<const QgsGeometrySelfIntersectionCheckError *>( other )->intersection().segment2 == intersection().segment2;
}
 
bool QgsGeometrySelfIntersectionCheckError::handleChanges( const QList<QgsGeometryCheck::Change> &changes )
{
  if ( !QgsSingleGeometryCheckError::handleChanges( changes ) )
    return false;
 
  for ( const QgsGeometryCheck::Change &change : changes )
  {
    if ( change.vidx.vertex == mIntersection.segment1 || change.vidx.vertex == mIntersection.segment1 + 1 || change.vidx.vertex == mIntersection.segment2 || change.vidx.vertex == mIntersection.segment2 + 1 )
    {
      return false;
    }
    else if ( change.vidx.vertex >= 0 )
    {
      if ( change.vidx.vertex < mIntersection.segment1 )
      {
        mIntersection.segment1 += change.type == QgsGeometryCheck::ChangeAdded ? 1 : -1;
      }
      if ( change.vidx.vertex < mIntersection.segment2 )
      {
        mIntersection.segment2 += change.type == QgsGeometryCheck::ChangeAdded ? 1 : -1;
      }
    }
  }
  return true;
}
 
void QgsGeometrySelfIntersectionCheckError::update( const QgsSingleGeometryCheckError *other )
{
  QgsSingleGeometryCheckError::update( other );
  // Static cast since this should only get called if isEqual == true
  const QgsGeometrySelfIntersectionCheckError *err = static_cast<const QgsGeometrySelfIntersectionCheckError *>( other );
  mIntersection.point = err->mIntersection.point;
}
 
void QgsGeometrySelfIntersectionCheck::fixError( const QMap<QString, QgsFeaturePool *> &featurePools, QgsGeometryCheckError *error, int method, const QMap<QString, int> & /*mergeAttributeIndices*/, Changes &changes ) const
{
  QgsFeaturePool *featurePool = featurePools[error->layerId()];
  QgsFeature feature;
  if ( !featurePool->getFeature( error->featureId(), feature ) )
  {
    error->setObsolete();
    return;
  }
 
  QgsGeometry featureGeom = feature.geometry();
  QgsAbstractGeometry *geom = featureGeom.get();
 
  const QgsVertexId vidx = error->vidx();
 
  // Check if ring still exists
  if ( !vidx.isValid( geom ) )
  {
    error->setObsolete();
    return;
  }
 
  const QgsGeometryCheckErrorSingle *singleError = static_cast<const QgsGeometryCheckErrorSingle *>( error );
  const QgsGeometryUtils::SelfIntersection &inter = static_cast<const QgsGeometrySelfIntersectionCheckError *>( singleError->singleError() )->intersection();
  // Check if error still applies
  bool ringIsClosed = false;
  const int nVerts = QgsGeometryCheckerUtils::polyLineSize( geom, vidx.part, vidx.ring, &ringIsClosed );
  if ( nVerts == 0 || inter.segment1 >= nVerts || inter.segment2 >= nVerts )
  {
    error->setObsolete();
    return;
  }
  const QgsPoint p1 = geom->vertexAt( QgsVertexId( vidx.part, vidx.ring, inter.segment1 ) );
  const QgsPoint q1 = geom->vertexAt( QgsVertexId( vidx.part, vidx.ring, inter.segment2 ) );
  const QgsPoint p2 = geom->vertexAt( QgsVertexId( vidx.part, vidx.ring, ( inter.segment1 + 1 ) % nVerts ) );
  const QgsPoint q2 = geom->vertexAt( QgsVertexId( vidx.part, vidx.ring, ( inter.segment2 + 1 ) % nVerts ) );
  QgsPoint s;
  bool intersection = false;
  if ( !QgsGeometryUtils::segmentIntersection( p1, p2, q1, q2, s, intersection, mContext->tolerance ) )
  {
    error->setObsolete();
    return;
  }
 
  // Fix with selected method
  if ( method == NoChange )
  {
    error->setFixed( method );
  }
  else if ( method == ToMultiObject || method == ToSingleObjects )
  {
    // Extract rings
    QgsPointSequence ring1, ring2;
    bool ring1EndsWithS = false;
    bool ring2EndsWithS = false;
    for ( int i = 0; i < nVerts; ++i )
    {
      if ( i <= inter.segment1 || i >= inter.segment2 + 1 )
      {
        ring1.append( geom->vertexAt( QgsVertexId( vidx.part, vidx.ring, i ) ) );
        ring1EndsWithS = false;
        if ( i == inter.segment2 + 1 )
        {
          ring2.append( s );
          ring2EndsWithS = true;
        }
      }
      else
      {
        ring2.append( geom->vertexAt( QgsVertexId( vidx.part, vidx.ring, i ) ) );
        ring2EndsWithS = true;
        if ( i == inter.segment1 + 1 )
        {
          ring1.append( s );
          ring1EndsWithS = false;
        }
      }
    }
    if ( nVerts == inter.segment2 + 1 )
    {
      ring2.append( s );
      ring2EndsWithS = true;
    }
    if ( ringIsClosed || ring1EndsWithS )
      ring1.append( ring1.front() ); // Ensure ring is closed
    if ( ringIsClosed || ring2EndsWithS )
      ring2.append( ring2.front() ); // Ensure ring is closed
 
    if ( ring1.size() < 3 + ( ringIsClosed || ring1EndsWithS ) || ring2.size() < 3 + ( ringIsClosed || ring2EndsWithS ) )
    {
      error->setFixFailed( tr( "Resulting geometry is degenerate" ) );
      return;
    }
    auto ringGeom1 = std::make_unique<QgsLineString>();
    ringGeom1->setPoints( ring1 );
    auto ringGeom2 = std::make_unique<QgsLineString>();
    ringGeom2->setPoints( ring2 );
 
    QgsAbstractGeometry *part = QgsGeometryCheckerUtils::getGeomPart( geom, vidx.part );
    // If is a polygon...
    if ( QgsCurvePolygon *poly = qgsgeometry_cast<QgsCurvePolygon *>( part ) )
    {
      // If self-intersecting ring is an interior ring, create separate holes
      if ( vidx.ring > 0 )
      {
        poly->removeInteriorRing( vidx.ring );
        poly->addInteriorRing( ringGeom1.release() );
        poly->addInteriorRing( ringGeom2.release() );
        changes[error->layerId()][feature.id()].append( Change( ChangeRing, ChangeRemoved, vidx ) );
        changes[error->layerId()][feature.id()].append( Change( ChangeRing, ChangeAdded, QgsVertexId( vidx.part, poly->ringCount() - 2 ) ) );
        changes[error->layerId()][feature.id()].append( Change( ChangeRing, ChangeAdded, QgsVertexId( vidx.part, poly->ringCount() - 1 ) ) );
        feature.setGeometry( featureGeom );
        featurePool->updateFeature( feature );
      }
      else
      {
        // If ring is exterior, build two polygons, and reassign interiors as necessary
        poly->setExteriorRing( ringGeom1.release() );
 
        // If original feature was a linear polygon, also create the new part as a linear polygon
        std::unique_ptr<QgsCurvePolygon> poly2 = qgsgeometry_cast<QgsPolygon *>( part ) ? std::make_unique<QgsPolygon>() : std::make_unique<QgsCurvePolygon>();
        poly2->setExteriorRing( ringGeom2.release() );
 
        // Reassing interiors as necessary
        std::unique_ptr<QgsGeometryEngine> geomEnginePoly1( QgsGeometry::createGeometryEngine( poly, mContext->tolerance ) );
        std::unique_ptr<QgsGeometryEngine> geomEnginePoly2( QgsGeometry::createGeometryEngine( poly2.get(), mContext->tolerance ) );
        for ( int n = poly->numInteriorRings(), i = n - 1; i >= 0; --i )
        {
          if ( !geomEnginePoly1->contains( poly->interiorRing( i ) ) )
          {
            if ( geomEnginePoly2->contains( poly->interiorRing( i ) ) )
            {
              poly2->addInteriorRing( qgsgeometry_cast<QgsCurve *>( poly->interiorRing( i )->clone() ) );
              // No point in adding ChangeAdded changes, since the entire poly2 is added anyways later on
            }
            poly->removeInteriorRing( i );
            changes[error->layerId()][feature.id()].append( Change( ChangeRing, ChangeRemoved, QgsVertexId( vidx.part, 1 + i ) ) );
          }
        }
 
        if ( method == ToMultiObject )
        {
          // If is already a geometry collection, just add the new polygon.
          if ( QgsGeometryCollection *collection = qgsgeometry_cast<QgsGeometryCollection *>( geom ) )
          {
            collection->addGeometry( poly2.release() );
            changes[error->layerId()][feature.id()].append( Change( ChangeRing, ChangeChanged, QgsVertexId( vidx.part, vidx.ring ) ) );
            changes[error->layerId()][feature.id()].append( Change( ChangePart, ChangeAdded, QgsVertexId( geom->partCount() - 1 ) ) );
            feature.setGeometry( featureGeom );
            featurePool->updateFeature( feature );
          }
          // Otherwise, create multipolygon
          else
          {
            auto multiPoly = std::make_unique<QgsMultiPolygon>();
            multiPoly->addGeometry( poly->clone() );
            multiPoly->addGeometry( poly2.release() );
            feature.setGeometry( QgsGeometry( std::move( multiPoly ) ) );
            featurePool->updateFeature( feature );
            changes[error->layerId()][feature.id()].append( Change( ChangeFeature, ChangeChanged ) );
          }
        }
        else // if ( method == ToSingleObjects )
        {
          QgsFeature newFeature;
          newFeature.setAttributes( feature.attributes() );
          newFeature.setGeometry( QgsGeometry( std::move( poly2 ) ) );
          feature.setGeometry( featureGeom );
          featurePool->updateFeature( feature );
          featurePool->addFeature( newFeature );
          changes[error->layerId()][feature.id()].append( Change( ChangeRing, ChangeChanged, QgsVertexId( vidx.part, vidx.ring ) ) );
          changes[error->layerId()][newFeature.id()].append( Change( ChangeFeature, ChangeAdded ) );
        }
      }
    }
    else if ( qgsgeometry_cast<QgsCurve *>( part ) )
    {
      if ( method == ToMultiObject )
      {
        if ( QgsGeometryCollection *geomCollection = qgsgeometry_cast<QgsGeometryCollection *>( geom ) )
        {
          geomCollection->removeGeometry( vidx.part );
          geomCollection->addGeometry( ringGeom1.release() );
          geomCollection->addGeometry( ringGeom2.release() );
          feature.setGeometry( featureGeom );
          featurePool->updateFeature( feature );
          changes[error->layerId()][feature.id()].append( Change( ChangePart, ChangeRemoved, QgsVertexId( vidx.part ) ) );
          changes[error->layerId()][feature.id()].append( Change( ChangePart, ChangeAdded, QgsVertexId( geomCollection->partCount() - 2 ) ) );
          changes[error->layerId()][feature.id()].append( Change( ChangePart, ChangeAdded, QgsVertexId( geomCollection->partCount() - 1 ) ) );
        }
        else
        {
          std::unique_ptr<QgsMultiCurve> multiCurve = std::make_unique<QgsMultiLineString>();
          multiCurve->addGeometry( ringGeom1.release() );
          multiCurve->addGeometry( ringGeom2.release() );
          feature.setGeometry( QgsGeometry( std::move( multiCurve ) ) );
          featurePool->updateFeature( feature );
          changes[error->layerId()][feature.id()].append( Change( ChangeFeature, ChangeChanged ) );
        }
      }
      else // if(method == ToSingleObjects)
      {
        if ( QgsGeometryCollection *geomCollection = qgsgeometry_cast<QgsGeometryCollection *>( geom ) )
        {
          geomCollection->removeGeometry( vidx.part );
          geomCollection->addGeometry( ringGeom1.release() );
          feature.setGeometry( featureGeom );
          featurePool->updateFeature( feature );
          changes[error->layerId()][feature.id()].append( Change( ChangePart, ChangeRemoved, QgsVertexId( vidx.part ) ) );
          changes[error->layerId()][feature.id()].append( Change( ChangePart, ChangeAdded, QgsVertexId( geomCollection->partCount() - 1 ) ) );
        }
        else
        {
          feature.setGeometry( QgsGeometry( std::move( ringGeom1 ) ) );
          featurePool->updateFeature( feature );
          changes[error->layerId()][feature.id()].append( Change( ChangeFeature, ChangeChanged, QgsVertexId( vidx.part ) ) );
        }
        QgsFeature newFeature;
        newFeature.setAttributes( feature.attributes() );
        newFeature.setGeometry( QgsGeometry( std::move( ringGeom2 ) ) );
        featurePool->addFeature( newFeature );
        changes[error->layerId()][newFeature.id()].append( Change( ChangeFeature, ChangeAdded ) );
      }
    }
    error->setFixed( method );
  }
  else
  {
    error->setFixFailed( tr( "Unknown method" ) );
  }
}
 
QStringList QgsGeometrySelfIntersectionCheck::resolutionMethods() const
{
  static const QStringList methods = QStringList()
                                     << tr( "Split feature into a multi-part feature" )
                                     << tr( "Split feature into multiple single-part features" )
                                     << tr( "No action" );
  return methods;
}
 
QList<QgsSingleGeometryCheckError *> QgsGeometrySelfIntersectionCheck::processGeometry( const QgsGeometry &geometry ) const
{
  QList<QgsSingleGeometryCheckError *> errors;
  const QgsAbstractGeometry *geom = geometry.constGet();
  for ( int iPart = 0, nParts = geom->partCount(); iPart < nParts; ++iPart )
  {
    for ( int iRing = 0, nRings = geom->ringCount( iPart ); iRing < nRings; ++iRing )
    {
      for ( const QgsGeometryUtils::SelfIntersection &inter : QgsGeometryUtils::selfIntersections( geom, iPart, iRing, mContext->tolerance ) )
      {
        errors.append( new QgsGeometrySelfIntersectionCheckError( this, geometry, QgsGeometry( inter.point.clone() ), QgsVertexId( iPart, iRing ), inter ) );
      }
    }
  }
  return errors;
}

QList<Qgis::GeometryType> QgsGeometrySelfIntersectionCheck::factoryCompatibleGeometryTypes()
{
  return { Qgis::GeometryType::Line, Qgis::GeometryType::Polygon };
}
 
bool QgsGeometrySelfIntersectionCheck::factoryIsCompatible( QgsVectorLayer *layer )
{
  return factoryCompatibleGeometryTypes().contains( layer->geometryType() );
}
 
QString QgsGeometrySelfIntersectionCheck::factoryDescription()
{
  return tr( "Self intersection" );
}
 
QgsGeometryCheck::Flags QgsGeometrySelfIntersectionCheck::factoryFlags()
{
  return QgsGeometryCheck::Flags();
}
 
QString QgsGeometrySelfIntersectionCheck::factoryId()
{
  return QStringLiteral( "QgsGeometrySelfIntersectionCheck" );
}
 
QgsGeometryCheck::CheckType QgsGeometrySelfIntersectionCheck::factoryCheckType()
{
  return QgsGeometryCheck::FeatureNodeCheck;
}