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C++ QgsMultiPolyline::reserve方法代码示例

本文整理汇总了C++中QgsMultiPolyline::reserve方法的典型用法代码示例。如果您正苦于以下问题:C++ QgsMultiPolyline::reserve方法的具体用法?C++ QgsMultiPolyline::reserve怎么用?C++ QgsMultiPolyline::reserve使用的例子?那么恭喜您, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在QgsMultiPolyline的用法示例。


在下文中一共展示了QgsMultiPolyline::reserve方法的1个代码示例,这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞,您的评价将有助于系统推荐出更棒的C++代码示例。

示例1: clipBufferLine

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.........
开发者ID:NyakudyaA,项目名称:QGIS,代码行数:101,代码来源:qgstransectsample.cpp


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