ColorEdges

VTKExamples/Cxx/Graphs/ColorEdges


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Question

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Code

ColorEdges.cxx

#include <vtkSmartPointer.h>
#include <vtkDataSetAttributes.h>
#include <vtkGraphLayoutView.h>
#include <vtkIntArray.h>
#include <vtkLookupTable.h>
#include <vtkMutableDirectedGraph.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkViewTheme.h>

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

  // Create a graph
  vtkIdType v1 = graph->AddVertex();
  vtkIdType v2 = graph->AddVertex();
  vtkIdType v3 = graph->AddVertex();
  graph->AddEdge(v1,v2);
  graph->AddEdge(v2,v3);

  // Create the color array
  vtkSmartPointer<vtkIntArray> edgeColors = 
    vtkSmartPointer<vtkIntArray>::New();
  edgeColors->SetNumberOfComponents(1);
  edgeColors->SetName("Color");

  vtkSmartPointer<vtkLookupTable> lookupTable = 
    vtkSmartPointer<vtkLookupTable>::New();
  lookupTable->SetNumberOfTableValues(2);
  lookupTable->SetTableValue(0, 1.0, 0.0, 0.0); // red
  lookupTable->SetTableValue(1, 0.0, 1.0, 0.0); // green
  lookupTable->Build();

  edgeColors->InsertNextValue(0);
  edgeColors->InsertNextValue(1);

  // Add the color array to the graph
  graph->GetEdgeData()->AddArray(edgeColors);

  vtkSmartPointer<vtkGraphLayoutView> graphLayoutView = 
    vtkSmartPointer<vtkGraphLayoutView>::New();
  graphLayoutView->AddRepresentationFromInput(graph);
  graphLayoutView->SetLayoutStrategyToTree();

  graphLayoutView->SetEdgeColorArrayName("Color");
  graphLayoutView->ColorEdgesOn();

  vtkSmartPointer<vtkViewTheme> theme = 
    vtkSmartPointer<vtkViewTheme>::New();
  theme->SetCellLookupTable(lookupTable);

  graphLayoutView->ApplyViewTheme(theme);
  graphLayoutView->ResetCamera();
  graphLayoutView->GetInteractor()->Initialize();
  graphLayoutView->GetInteractor()->Start();

  return EXIT_SUCCESS;
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

project(ColorEdges)

find_package(VTK COMPONENTS 
  vtkCommonCore
  vtkCommonDataModel
  vtkInteractionStyle
  vtkRenderingCore
  vtkRenderingFreeType
  vtkRenderingOpenGL2
  vtkViewsCore
  vtkViewsInfovis QUIET)
if (NOT VTK_FOUND)
  message("Skipping ColorEdges: ${VTK_NOT_FOUND_MESSAGE}")
  return ()
endif()
message (STATUS "VTK_VERSION: ${VTK_VERSION}")
if (VTK_VERSION VERSION_LESS "8.90.0")
  # old system
  include(${VTK_USE_FILE})
  add_executable(ColorEdges MACOSX_BUNDLE ColorEdges.cxx )
  target_link_libraries(ColorEdges PRIVATE ${VTK_LIBRARIES})
else ()
  # include all components
  add_executable(ColorEdges MACOSX_BUNDLE ColorEdges.cxx )
  target_link_libraries(ColorEdges PRIVATE ${VTK_LIBRARIES})
  # vtk_module_autoinit is needed
  vtk_module_autoinit(
    TARGETS ColorEdges
    MODULES ${VTK_LIBRARIES}
    )
endif () 

Download and Build ColorEdges

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

cd ColorEdges/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:

./ColorEdges

WINDOWS USERS

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