C++ QgsMultiPolyline::append方法代码示例

QgsGeometry *QgsRubberBand::asGeometry()
{
  QgsGeometry *geom = NULL;

  switch ( mGeometryType )
  {
    case QGis::Polygon:
    {
      QgsPolygon polygon;
      QList< QList<QgsPoint> >::const_iterator it = mPoints.constBegin();
      for ( ; it != mPoints.constEnd(); ++it )
      {
        polygon.append( getPolyline( *it ) );
      }
      geom = QgsGeometry::fromPolygon( polygon );
      break;
    }

    case QGis::Point:
    {
      QgsMultiPoint multiPoint;

      QList< QList<QgsPoint> >::const_iterator it = mPoints.constBegin();
      for ( ; it != mPoints.constEnd(); ++it )
      {
        multiPoint += getPolyline( *it );
      }
      geom = QgsGeometry::fromMultiPoint( multiPoint );
      break;
    }

    case QGis::Line:
    default:
    {
      if ( mPoints.size() > 0 )
      {
        if ( mPoints.size() > 1 )
        {
          QgsMultiPolyline multiPolyline;
          QList< QList<QgsPoint> >::const_iterator it = mPoints.constBegin();
          for ( ; it != mPoints.constEnd(); ++it )
          {
            multiPolyline.append( getPolyline( *it ) );
          }
          geom = QgsGeometry::fromMultiPolyline( multiPolyline );
        }
        else
        {
          geom = QgsGeometry::fromPolyline( getPolyline( mPoints[0] ) );
        }
      }
      break;
    }
  }
  return geom;
}

QgsGeometry* QgsTransectSample::clipBufferLine( const QgsGeometry& stratumGeom, QgsGeometry* clippedBaseline, double tolerance )
{
  if ( !stratumGeom || !clippedBaseline || clippedBaseline->wkbType() == QgsWkbTypes::Unknown )
  {
    return nullptr;
  }

  QgsGeometry usedBaseline = *clippedBaseline;
  if ( mBaselineSimplificationTolerance >= 0 )
  {
    //int verticesBefore = usedBaseline->asMultiPolyline().count();
    usedBaseline = clippedBaseline->simplify( mBaselineSimplificationTolerance );
    if ( usedBaseline.isEmpty() )
    {
      return nullptr;
    }
    //int verticesAfter = usedBaseline->asMultiPolyline().count();

    //debug: write to file
    /*QgsVectorFileWriter debugWriter( "/tmp/debug.shp", "utf-8", QgsFields(), QgsWkbTypes::LineString, &( mStrataLayer->crs() ) );
    QgsFeature debugFeature; debugFeature.setGeometry( usedBaseline );
    debugWriter.addFeature( debugFeature );*/
  }

  double currentBufferDist = tolerance;
  int maxLoops = 10;

  for ( int i = 0; i < maxLoops; ++i )
  {
    //loop with tolerance: create buffer, convert buffer to line, clip line by stratum, test if result is (single) line
    QgsGeometry clipBaselineBuffer = usedBaseline.buffer( currentBufferDist, 8 );
    if ( clipBaselineBuffer.isEmpty() )
    {
      continue;
    }

    //it is also possible that clipBaselineBuffer is a multipolygon
    QgsGeometry bufferLine; //buffer line or multiline
    QgsGeometry bufferLineClipped;
    QgsMultiPolyline mpl;
    if ( clipBaselineBuffer.isMultipart() )
    {
      QgsMultiPolygon bufferMultiPolygon = clipBaselineBuffer.asMultiPolygon();
      if ( bufferMultiPolygon.size() < 1 )
      {
        continue;
      }

      for ( int j = 0; j < bufferMultiPolygon.size(); ++j )
      {
        int size = bufferMultiPolygon.at( j ).size();
        for ( int k = 0; k < size; ++k )
        {
          mpl.append( bufferMultiPolygon.at( j ).at( k ) );
        }
      }
      bufferLine = QgsGeometry::fromMultiPolyline( mpl );
    }
    else
    {
      QgsPolygon bufferPolygon = clipBaselineBuffer.asPolygon();
      if ( bufferPolygon.size() < 1 )
      {
        continue;
      }

      int size = bufferPolygon.size();
      mpl.reserve( size );
      for ( int j = 0; j < size; ++j )
      {
        mpl.append( bufferPolygon[j] );
      }
      bufferLine = QgsGeometry::fromMultiPolyline( mpl );
    }
    bufferLineClipped = bufferLine.intersection( stratumGeom );

    if ( bufferLineClipped.isEmpty() && bufferLineClipped.type() == QgsWkbTypes::LineGeometry )
    {
      //if stratumGeom is a multipolygon, bufferLineClipped must intersect each part
      bool bufferLineClippedIntersectsStratum = true;
      if ( stratumGeom.wkbType() == QgsWkbTypes::MultiPolygon || stratumGeom.wkbType() == QgsWkbTypes::MultiPolygon25D )
      {
        QVector<QgsPolygon> multiPoly = stratumGeom.asMultiPolygon();
        QVector<QgsPolygon>::const_iterator multiIt = multiPoly.constBegin();
        for ( ; multiIt != multiPoly.constEnd(); ++multiIt )
        {
          QgsGeometry poly = QgsGeometry::fromPolygon( *multiIt );
          if ( !poly.intersects( bufferLineClipped ) )
          {
            bufferLineClippedIntersectsStratum = false;
            break;
          }
        }
      }

      if ( bufferLineClippedIntersectsStratum )
      {
        return new QgsGeometry( bufferLineClipped );
      }
    }
//.........这里部分代码省略.........

QgsGeometry* QgsTransectSample::clipBufferLine( QgsGeometry* stratumGeom, QgsGeometry* clippedBaseline, double tolerance )
{
  if ( !stratumGeom || !clippedBaseline || clippedBaseline->wkbType() == QGis::WKBUnknown )
  {
    return 0;
  }

  double currentBufferDist = tolerance;
  int maxLoops = 10;

  for ( int i = 0; i < maxLoops; ++i )
  {
    //loop with tolerance: create buffer, convert buffer to line, clip line by stratum, test if result is (single) line
    QgsGeometry* clipBaselineBuffer = clippedBaseline->buffer( currentBufferDist, 8 );
    if ( !clipBaselineBuffer )
    {
      delete clipBaselineBuffer;
      continue;
    }

    //it is also possible that clipBaselineBuffer is a multipolygon
    QgsGeometry* bufferLine = 0; //buffer line or multiline
    QgsGeometry* bufferLineClipped = 0;
    QgsMultiPolyline mpl;
    if ( clipBaselineBuffer->isMultipart() )
    {
      QgsMultiPolygon bufferMultiPolygon = clipBaselineBuffer->asMultiPolygon();
      if ( bufferMultiPolygon.size() < 1 )
      {
        delete clipBaselineBuffer;
        continue;
      }

      for ( int j = 0; j < bufferMultiPolygon.size(); ++j )
      {
        int size = bufferMultiPolygon.at( j ).size();
        for ( int k = 0; k < size; ++k )
        {
          mpl.append( bufferMultiPolygon.at( j ).at( k ) );
        }
      }
      bufferLine = QgsGeometry::fromMultiPolyline( mpl );
    }
    else
    {
      QgsPolygon bufferPolygon = clipBaselineBuffer->asPolygon();
      if ( bufferPolygon.size() < 1 )
      {
        delete clipBaselineBuffer;
        continue;
      }

      int size = bufferPolygon.size();
      for ( int j = 0; j < size; ++j )
      {
        mpl.append( bufferPolygon[j] );
      }
      bufferLine = QgsGeometry::fromMultiPolyline( mpl );
    }
    bufferLineClipped = bufferLine->intersection( stratumGeom );

    if ( bufferLineClipped && bufferLineClipped->type() == QGis::Line )
    {
      //if stratumGeom is a multipolygon, bufferLineClipped must intersect each part
      bool bufferLineClippedIntersectsStratum = true;
      if ( stratumGeom->wkbType() == QGis::WKBMultiPolygon || stratumGeom->wkbType() == QGis::WKBMultiPolygon25D )
      {
        QVector<QgsPolygon> multiPoly = stratumGeom->asMultiPolygon();
        QVector<QgsPolygon>::const_iterator multiIt = multiPoly.constBegin();
        for ( ; multiIt != multiPoly.constEnd(); ++multiIt )
        {
          QgsGeometry* poly = QgsGeometry::fromPolygon( *multiIt );
          if ( !poly->intersects( bufferLineClipped ) )
          {
            bufferLineClippedIntersectsStratum = false;
            delete poly;
            break;
          }
          delete poly;
        }
      }

      if ( bufferLineClippedIntersectsStratum )
      {
        return bufferLineClipped;
      }
    }

    delete bufferLineClipped; delete clipBaselineBuffer; delete bufferLine;
    currentBufferDist /= 2;
  }

  return 0; //no solution found even with reduced tolerances
}