Method ExtendGraph

Infovis/Core/vtkMergeGraphs.cxx:156–252

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//------------------------------------------------------------------------------
int vtkMergeGraphs::ExtendGraph(vtkMutableGraphHelper* builder, vtkGraph* graph2)
{
  vtkAbstractArray* ped_ids1 = builder->GetGraph()->GetVertexData()->GetPedigreeIds();
  if (!ped_ids1)
  {
    vtkErrorMacro("First graph must have pedigree ids");
    return 0;
  }

  vtkAbstractArray* ped_ids2 = graph2->GetVertexData()->GetPedigreeIds();
  if (!ped_ids1)
  {
    vtkErrorMacro("Second graph must have pedigree ids");
    return 0;
  }

  // Find matching vertex arrays
  std::map<vtkAbstractArray*, vtkAbstractArray*> vert_array_map;
  vtkDataSetAttributes* vert_data1 = builder->GetGraph()->GetVertexData();
  vtkMergeGraphsCreateArrayMapping(vert_array_map, vert_data1, graph2->GetVertexData());

  // Find graph1 vertices matching graph2's pedigree ids
  vtkIdType n2 = graph2->GetNumberOfVertices();
  std::vector<vtkIdType> graph2_to_graph1(n2);
  for (vtkIdType vert2 = 0; vert2 < n2; ++vert2)
  {
    vtkIdType vert1 = ped_ids1->LookupValue(ped_ids2->GetVariantValue(vert2));
    if (vert1 == -1)
    {
      vert1 = builder->AddVertex();
      vtkMergeGraphsAddRow(vert_data1, vert2, vert_array_map);
    }
    graph2_to_graph1[vert2] = vert1;
  }

  // Find matching edge arrays
  std::map<vtkAbstractArray*, vtkAbstractArray*> edge_array_map;
  vtkDataSetAttributes* edge_data1 = builder->GetGraph()->GetEdgeData();
  vtkMergeGraphsCreateArrayMapping(edge_array_map, edge_data1, graph2->GetEdgeData());

  // For each edge in graph2, add it to the output
  vtkSmartPointer<vtkEdgeListIterator> it = vtkSmartPointer<vtkEdgeListIterator>::New();
  graph2->GetEdges(it);
  while (it->HasNext())
  {
    vtkEdgeType e = it->Next();
    vtkIdType source = graph2_to_graph1[e.Source];
    vtkIdType target = graph2_to_graph1[e.Target];
    if (source != -1 && target != -1)
    {
      builder->AddEdge(source, target);
      vtkMergeGraphsAddRow(edge_data1, e.Id, edge_array_map);
    }
  }

  // Remove edges if using an edge window.
  if (this->UseEdgeWindow)
  {