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LabelVerticesAndEdges

vtk-examples/Cxx/Graphs/LabelVerticesAndEdges

Description

This example sets and displays labels of vertices and edges of a graph.

Other languages

See (Python)

Question

If you have a question about this example, please use the VTK Discourse Forum

Code

LabelVerticesAndEdges.cxx

#include <vtkCircularLayoutStrategy.h>
#include <vtkDataSetAttributes.h>
#include <vtkDoubleArray.h>
#include <vtkGraphLayoutView.h>
#include <vtkIntArray.h>
#include <vtkMutableUndirectedGraph.h>
#include <vtkNamedColors.h>
#include <vtkNew.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderedGraphRepresentation.h>
#include <vtkRenderer.h>
#include <vtkTextProperty.h>

int main(int, char*[])
{
  vtkNew<vtkNamedColors> colors;

  vtkNew<vtkMutableUndirectedGraph> g;

  // Create 3 vertices
  vtkIdType v1 = g->AddVertex();
  vtkIdType v2 = g->AddVertex();
  vtkIdType v3 = g->AddVertex();

  // Create a fully connected graph
  g->AddEdge(v1, v2);
  g->AddEdge(v2, v3);
  g->AddEdge(v1, v3);

  // Create the edge weight array
  vtkNew<vtkDoubleArray> weights;
  weights->SetNumberOfComponents(1);
  weights->SetName("Weights");

  // Set the edge weights
  weights->InsertNextValue(1.0);
  weights->InsertNextValue(1.0);
  weights->InsertNextValue(2.0);

  // Create an array for the vertex labels
  vtkNew<vtkIntArray> vertexIDs;
  vertexIDs->SetNumberOfComponents(1);
  vertexIDs->SetName("VertexIDs");

  // Set the vertex labels
  vertexIDs->InsertNextValue(0);
  vertexIDs->InsertNextValue(1);
  vertexIDs->InsertNextValue(2);

  // Add the edge weight array to the graph
  g->GetEdgeData()->AddArray(weights);
  g->GetVertexData()->AddArray(vertexIDs);

  vtkNew<vtkCircularLayoutStrategy> circularLayoutStrategy;

  vtkNew<vtkGraphLayoutView> graphLayoutView;
  graphLayoutView->AddRepresentationFromInput(g);

  graphLayoutView->SetLayoutStrategy(circularLayoutStrategy);
  graphLayoutView->SetVertexLabelVisibility(true);
  graphLayoutView->SetEdgeLabelVisibility(true);
  graphLayoutView->SetEdgeLabelArrayName("Weights");     // default is "labels"
  graphLayoutView->SetVertexLabelArrayName("VertexIDs"); // default is "labels"
  dynamic_cast<vtkRenderedGraphRepresentation*>(
      graphLayoutView->GetRepresentation())
      ->GetVertexLabelTextProperty()
      ->SetColor(colors->GetColor3d("Yellow").GetData());
  dynamic_cast<vtkRenderedGraphRepresentation*>(
      graphLayoutView->GetRepresentation())
      ->GetEdgeLabelTextProperty()
      ->SetColor(colors->GetColor3d("Lime").GetData());
  graphLayoutView->GetRenderer()->SetBackground(
      colors->GetColor3d("Navy").GetData());
  graphLayoutView->GetRenderer()->SetBackground2(
      colors->GetColor3d("MidnightBlue").GetData());
  graphLayoutView->GetRenderWindow()->SetWindowName("LabelVerticesAndEdges");
  graphLayoutView->ResetCamera();
  graphLayoutView->Render();
  graphLayoutView->GetInteractor()->Start();

  return EXIT_SUCCESS;
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.12 FATAL_ERROR)

project(LabelVerticesAndEdges)

find_package(VTK COMPONENTS 
)

if (NOT VTK_FOUND)
  message(FATAL_ERROR "LabelVerticesAndEdges: Unable to find the VTK build folder.")
endif()

# Prevent a "command line is too long" failure in Windows.
set(CMAKE_NINJA_FORCE_RESPONSE_FILE "ON" CACHE BOOL "Force Ninja to use response files.")
add_executable(LabelVerticesAndEdges MACOSX_BUNDLE LabelVerticesAndEdges.cxx )
  target_link_libraries(LabelVerticesAndEdges PRIVATE ${VTK_LIBRARIES}
)
# vtk_module_autoinit is needed
vtk_module_autoinit(
  TARGETS LabelVerticesAndEdges
  MODULES ${VTK_LIBRARIES}
)

Download and Build LabelVerticesAndEdges

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

cd LabelVerticesAndEdges/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:

./LabelVerticesAndEdges

WINDOWS USERS

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