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IterateOverLines

vtk-examples/Cxx/PolyData/IterateOverLines

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Question

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Code

IterateOverLines.cxx

#include <vtkCellArray.h>
#include <vtkLine.h>
#include <vtkNew.h>
#include <vtkPoints.h>
#include <vtkPolyData.h>

int main(int, char*[])
{
  double origin[3] = {0.0, 0.0, 0.0};
  double p0[3] = {1.0, 0.0, 0.0};
  double p1[3] = {0.0, 1.0, 0.0};
  double p2[3] = {0.0, 1.0, 2.0};
  double p3[3] = {1.0, 2.0, 3.0};

  // Create a vtkPoints object and store the points in it
  vtkNew<vtkPoints> points;
  points->InsertNextPoint(origin);
  points->InsertNextPoint(p0);
  points->InsertNextPoint(p1);
  points->InsertNextPoint(p2);
  points->InsertNextPoint(p3);

  // Create a cell array to store the lines in and add the lines to it
  vtkNew<vtkCellArray> lines;

  // Create four lines
  for (unsigned int i = 0; i < 4; i++)
  {
    vtkNew<vtkLine> line;
    line->GetPointIds()->SetId(0, i);
    line->GetPointIds()->SetId(1, i + 1);
    lines->InsertNextCell(line);
  }

  // Create a polydata to store everything in
  vtkNew<vtkPolyData> linesPolyData;

  // Add the points to the dataset
  linesPolyData->SetPoints(points);

  // Add the lines to the dataset
  linesPolyData->SetLines(lines);

  std::cout << "There are " << linesPolyData->GetNumberOfLines() << " lines."
            << std::endl;

  linesPolyData->GetLines()->InitTraversal();
  vtkNew<vtkIdList> idList;
  while (linesPolyData->GetLines()->GetNextCell(idList))
  {
    std::cout << "Line has " << idList->GetNumberOfIds() << " points."
              << std::endl;

    for (vtkIdType pointId = 0; pointId < idList->GetNumberOfIds(); pointId++)
    {
      std::cout << idList->GetId(pointId) << " ";
    }
    std::cout << std::endl;
  }
  return EXIT_SUCCESS;
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

project(IterateOverLines)

find_package(VTK COMPONENTS 
  vtkCommonCore
  vtkCommonDataModel
  QUIET
)

if (NOT VTK_FOUND)
  message("Skipping IterateOverLines: ${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(IterateOverLines MACOSX_BUNDLE IterateOverLines.cxx )
  target_link_libraries(IterateOverLines PRIVATE ${VTK_LIBRARIES})
else ()
  # include all components
  add_executable(IterateOverLines MACOSX_BUNDLE IterateOverLines.cxx )
  target_link_libraries(IterateOverLines PRIVATE ${VTK_LIBRARIES})
  # vtk_module_autoinit is needed
  vtk_module_autoinit(
    TARGETS IterateOverLines
    MODULES ${VTK_LIBRARIES}
    )
endif ()

Download and Build IterateOverLines

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

cd IterateOverLines/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:

./IterateOverLines

WINDOWS USERS

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