# DeletePoint

VTKExamples/Cxx/PolyData/DeletePoint

### Code

DeletePoint.cxx

    #include <vtkSmartPointer.h>
    #include <vtkPoints.h>
    #include <vtkPolyData.h>

    void OutputPoints(vtkSmartPointer<vtkPoints> points);
    void ReallyDeletePoint(vtkSmartPointer<vtkPoints> points, vtkIdType id);

    int main(int, char *[])
    {
      // Create a set of points
      vtkSmartPointer<vtkPoints> points =
        vtkSmartPointer<vtkPoints>::New();
      points->InsertNextPoint ( 1.0, 0.0, 0.0 );
      points->InsertNextPoint ( 0.0, 1.0, 0.0 );
      points->InsertNextPoint ( 0.0, 0.0, 1.0 );

      std::cout << "Number of points: " << points->GetNumberOfPoints() << std::endl;
      OutputPoints(points);

      ReallyDeletePoint(points, 1);

      std::cout << "Number of points: " << points->GetNumberOfPoints() << std::endl;
      OutputPoints(points);

      return EXIT_SUCCESS;
    }

    void OutputPoints(vtkSmartPointer<vtkPoints> points)
    {
      for(vtkIdType i = 0; i < points->GetNumberOfPoints(); i++)
      {
        double p[3];
        points->GetPoint(i,p);
        cout << p[0] << " " << p[1] << " " << p[2] << endl;
      }
    }

    void ReallyDeletePoint(vtkSmartPointer<vtkPoints> points, vtkIdType id)
    {
      vtkSmartPointer<vtkPoints> newPoints =
        vtkSmartPointer<vtkPoints>::New();

      for(vtkIdType i = 0; i < points->GetNumberOfPoints(); i++)
      {
        if(i != id)
        {
          double p[3];
          points->GetPoint(i,p);
          newPoints->InsertNextPoint(p);
        }
      }

      points->ShallowCopy(newPoints);
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

    project(DeletePoint)

    find_package(VTK COMPONENTS
      vtkCommonCore
      vtkCommonDataModel QUIET)
    if (NOT VTK_FOUND)
      message("Skipping DeletePoint: ${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(DeletePoint MACOSX_BUNDLE DeletePoint.cxx )
      target_link_libraries(DeletePoint PRIVATE ${VTK_LIBRARIES})
    else ()
      # include all components
      add_executable(DeletePoint MACOSX_BUNDLE DeletePoint.cxx )
      target_link_libraries(DeletePoint PRIVATE ${VTK_LIBRARIES})
      # vtk_module_autoinit is needed
      vtk_module_autoinit(
        TARGETS DeletePoint
        MODULES ${VTK_LIBRARIES}
        )
    endif ()

### Download and Build DeletePoint

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

    cd DeletePoint/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:

    ./DeletePoint

WINDOWS USERS

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