VisualizeDirectedGraph

VTKExamples/Cxx/Graphs/VisualizeDirectedGraph


Code

VisualizeDirectedGraph.cxx

#include <vtkSmartPointer.h>

#include <vtkActor.h>
#include <vtkGlyph3D.h>
#include <vtkGlyphSource2D.h>
#include <vtkGraphLayout.h>
#include <vtkGraphLayoutView.h>
#include <vtkGraphToPolyData.h>
#include <vtkMutableDirectedGraph.h>
#include <vtkPolyDataMapper.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkSimple2DLayoutStrategy.h>

int main(int, char *[])
{
  vtkSmartPointer<vtkMutableDirectedGraph> g = 
    vtkSmartPointer<vtkMutableDirectedGraph>::New();

  vtkIdType v1 = g->AddVertex();
  vtkIdType v2 = g->AddVertex();
  vtkIdType v3 = g->AddVertex();

  g->AddEdge ( v1, v2 );
  g->AddEdge ( v2, v3 );
  g->AddEdge ( v3, v1 );

  // Do layout manually before handing graph to the view.
  // This allows us to know the positions of edge arrows.
  vtkSmartPointer<vtkGraphLayoutView> graphLayoutView = 
    vtkSmartPointer<vtkGraphLayoutView>::New();

  vtkSmartPointer<vtkGraphLayout> layout = 
    vtkSmartPointer<vtkGraphLayout>::New();
  vtkSmartPointer<vtkSimple2DLayoutStrategy> strategy = 
    vtkSmartPointer<vtkSimple2DLayoutStrategy>::New();
  layout->SetInput(g);
  layout->SetLayoutStrategy(strategy);

  // Tell the view to use the vertex layout we provide
  graphLayoutView->SetLayoutStrategyToPassThrough();
  // The arrows will be positioned on a straight line between two
  // vertices so tell the view not to draw arcs for parallel edges
  graphLayoutView->SetEdgeLayoutStrategyToPassThrough();

  // Add the graph to the view. This will render vertices and edges,
  // but not edge arrows.
  graphLayoutView->AddRepresentationFromInputConnection(
    layout->GetOutputPort());

  // Manually create an actor containing the glyphed arrows.
  vtkSmartPointer<vtkGraphToPolyData> graphToPoly = 
    vtkSmartPointer<vtkGraphToPolyData>::New();
  graphToPoly->SetInputConnection(layout->GetOutputPort());
  graphToPoly->EdgeGlyphOutputOn();

  // Set the position (0: edge start, 1: edge end) where
  // the edge arrows should go.
  graphToPoly->SetEdgeGlyphPosition(0.98);

  // Make a simple edge arrow for glyphing.
  vtkSmartPointer<vtkGlyphSource2D> arrowSource = 
    vtkSmartPointer<vtkGlyphSource2D>::New();
  arrowSource->SetGlyphTypeToEdgeArrow();
  arrowSource->SetScale(0.1);
  arrowSource->Update();

  // Use Glyph3D to repeat the glyph on all edges.
  vtkSmartPointer<vtkGlyph3D> arrowGlyph = 
    vtkSmartPointer<vtkGlyph3D>::New();
  arrowGlyph->SetInputConnection(0, graphToPoly->GetOutputPort(1));
  arrowGlyph->SetInputConnection(1, arrowSource->GetOutputPort());

  // Add the edge arrow actor to the view.
  vtkSmartPointer<vtkPolyDataMapper> arrowMapper = 
    vtkSmartPointer<vtkPolyDataMapper>::New();
  arrowMapper->SetInputConnection(arrowGlyph->GetOutputPort());
  vtkSmartPointer<vtkActor> arrowActor = 
    vtkSmartPointer<vtkActor>::New();
  arrowActor->SetMapper(arrowMapper);
  graphLayoutView->GetRenderer()->AddActor(arrowActor);

  graphLayoutView->ResetCamera();
  graphLayoutView->Render();
  graphLayoutView->GetInteractor()->Start();

  return EXIT_SUCCESS;
}

CMakeLists.txt

cmake_minimum_required(VERSION 2.8)

PROJECT(VisualizeDirectedGraph)

find_package(VTK REQUIRED)
include(${VTK_USE_FILE})

add_executable(VisualizeDirectedGraph MACOSX_BUNDLE VisualizeDirectedGraph.cxx )

target_link_libraries(VisualizeDirectedGraph ${VTK_LIBRARIES})

Download and Build VisualizeDirectedGraph

Click here to download VisualizeDirectedGraph and its CMakeLists.txt file. Once the tarball VisualizeDirectedGraph.tar has been downloaded and extracted,

cd VisualizeDirectedGraph/build 

If VTK is installed:

cmake ..

If VTK is not installed but compiled on your system, you will need to specify the path to your VTK build:

cmake -DVTK_DIR:PATH=/home/me/vtk_build ..

Build the project:

make

and run it:

./VisualizeDirectedGraph

WINDOWS USERS

Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.