VTK/Examples/Cxx/Graphs/SelectedVerticesAndEdgesObserver

#include <vtkSmartPointer.h>
#include <vtkCallbackCommand.h>
#include <vtkAnnotationLink.h>
#include <vtkRenderedGraphRepresentation.h>
#include <vtkRenderer.h>
#include <vtkDoubleArray.h>
#include <vtkSelectionNode.h>
#include <vtkIdTypeArray.h>
#include <vtkSelection.h>
#include <vtkRenderWindow.h>
#include <vtkUnsignedCharArray.h>
#include <vtkObjectFactory.h>
#include <vtkGraphLayoutStrategy.h>
#include <vtkGraphLayoutView.h>
#include <vtkGraphWriter.h>
#include <vtkMutableUndirectedGraph.h>
#include <vtkRenderWindowInteractor.h>
 
void SelectionCallbackFunction(vtkObject* caller, long unsigned int eventId, void* clientData, void* callData);
 
int main(int, char *[])
{
  vtkSmartPointer<vtkMutableUndirectedGraph> g =
    vtkSmartPointer<vtkMutableUndirectedGraph>::New();
 
  vtkIdType v1 = g->AddVertex();
  vtkIdType v2 = g->AddVertex();
 
  g->AddEdge(v1, v2);
  g->AddEdge(v1, v2);
 
  vtkSmartPointer<vtkCallbackCommand> selectionCallback =
    vtkSmartPointer<vtkCallbackCommand>::New();
  selectionCallback->SetCallback (SelectionCallbackFunction);
 
  vtkSmartPointer<vtkGraphLayoutView> view =
    vtkSmartPointer<vtkGraphLayoutView>::New();
  view->AddRepresentationFromInput(g);
  view->SetLayoutStrategy("Simple 2D");
  view->GetRepresentation()->GetAnnotationLink()->AddObserver("AnnotationChangedEvent", selectionCallback);
 
  view->ResetCamera();
  view->Render();
 
  view->GetInteractor()->Start();
 
  return EXIT_SUCCESS;
}
 
void SelectionCallbackFunction(vtkObject* caller, long unsigned int eventId, void* clientData, void* callData)
{
 
  vtkAnnotationLink* annotationLink =
    static_cast<vtkAnnotationLink*>(caller);
 
  vtkSelection* selection = annotationLink->GetCurrentSelection();
  vtkSelectionNode* vertices;
  vtkSelectionNode* edges;
  if(selection->GetNode(0)->GetFieldType() == vtkSelectionNode::VERTEX)
    {
    vertices = selection->GetNode(0);
    }
  else if(selection->GetNode(0)->GetFieldType() == vtkSelectionNode::EDGE)
    {
    edges = selection->GetNode(0);
    }
 
  if(selection->GetNode(1)->GetFieldType() == vtkSelectionNode::VERTEX)
    {
    vertices = selection->GetNode(1);
    }
  else if(selection->GetNode(1)->GetFieldType() == vtkSelectionNode::EDGE)
    {
    edges = selection->GetNode(1);
    }
 
  vtkIdTypeArray* vertexList = vtkIdTypeArray::SafeDownCast(vertices->GetSelectionList());
  std::cout << "There are " << vertexList->GetNumberOfTuples() << " vertices selected." << std::endl;
 
  if(vertexList->GetNumberOfTuples() > 0)
    {
    std::cout << "Vertex Ids: ";
    }
  for(vtkIdType i = 0; i < vertexList->GetNumberOfTuples(); i++)
    {
    std::cout << vertexList->GetValue(i) << " ";
    }
 
  std::cout << std::endl;
  vtkIdTypeArray* edgeList = vtkIdTypeArray::SafeDownCast(edges->GetSelectionList());
  std::cout << "There are " << edgeList->GetNumberOfTuples() << " edges selected." << std::endl;
  if(edgeList->GetNumberOfTuples() > 0)
    {
    std::cout << "Edge Ids: ";
    }
 
  for(vtkIdType i = 0; i < edgeList->GetNumberOfTuples(); i++)
    {
    std::cout << edgeList->GetValue(i) << " ";
    }
  std::cout << std::endl;
 
}