[vtkusers] Problem with vtkPolyLine width greater than 20

[Stefan Köhnen]

Hello,

I have a problem while trying to increase the width of a vtkPolyLine.
No matter what I try, the width never seems to become bigger for
values above 20.

For values below 20, the method SetLineWidth works as expected.

My question is if there is a limitation that prevents me to increase
the width further or is there an error in my implementation.

To explain my problem better I modified the PolyLine-Example.
I added SetLineWidth for the vtkProperty of the vtkActor.


Greetings,

Stefan Köhnen

Here is the code:

#include <vtkVersion.h>
#include <vtkSmartPointer.h>
#include <vtkCellArray.h>
#include <vtkCellData.h>
#include <vtkDoubleArray.h>
#include <vtkPoints.h>
#include <vtkPolyLine.h>
#include <vtkPolyData.h>
#include <vtkPolyDataMapper.h>
#include <vtkActor.h>
#include <vtkRenderWindow.h>
#include <vtkRenderer.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkProperty.h>

int main(int, char *[])
{
  // Create five points.
  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
  vtkSmartPointer<vtkPoints> points =
    vtkSmartPointer<vtkPoints>::New();
  points->InsertNextPoint(origin);
  points->InsertNextPoint(p0);
  points->InsertNextPoint(p1);
  points->InsertNextPoint(p2);
  points->InsertNextPoint(p3);

  vtkSmartPointer<vtkPolyLine> polyLine =
    vtkSmartPointer<vtkPolyLine>::New();
  polyLine->GetPointIds()->SetNumberOfIds(5);
  for(unsigned int i = 0; i < 5; i++)
    {
    polyLine->GetPointIds()->SetId(i,i);
    }

  // Create a cell array to store the lines in and add the lines to it
  vtkSmartPointer<vtkCellArray> cells =
    vtkSmartPointer<vtkCellArray>::New();
  cells->InsertNextCell(polyLine);

  // Create a polydata to store everything in
  vtkSmartPointer<vtkPolyData> polyData =
    vtkSmartPointer<vtkPolyData>::New();

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

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

  // Setup actor and mapper
  vtkSmartPointer<vtkPolyDataMapper> mapper =
    vtkSmartPointer<vtkPolyDataMapper>::New();
#if VTK_MAJOR_VERSION <= 5
  mapper->SetInput(polyData);
#else
  mapper->SetInputData(polyData);
#endif

  vtkSmartPointer<vtkActor> actor =
    vtkSmartPointer<vtkActor>::New();
  actor->SetMapper(mapper);

  ////////////////////////////////////////////////////////////////////////////
  // Here is the explained change - Set width of line
  actor->GetProperty()->SetLineWidth(30.0f);
  ////////////////////////////////////////////////////////////////////////////


  // Setup render window, renderer, and interactor
  vtkSmartPointer<vtkRenderer> renderer =
    vtkSmartPointer<vtkRenderer>::New();
  vtkSmartPointer<vtkRenderWindow> renderWindow =
    vtkSmartPointer<vtkRenderWindow>::New();
  renderWindow->AddRenderer(renderer);
  vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor =
    vtkSmartPointer<vtkRenderWindowInteractor>::New();
  renderWindowInteractor->SetRenderWindow(renderWindow);
  renderer->AddActor(actor);

  renderWindow->Render();
  renderWindowInteractor->Start();

  return EXIT_SUCCESS;
}