[vtkusers] How to draw a line (in display)

Erkang Cheng ekyaya at gmail.com
Wed Apr 14 21:37:39 EDT 2010


Hi all:

I have a question about drawing a line.
Actually, I want to draw a line in display window. But when I change these
two points, the line doesn't looks correct.
I follow the example :

//create two points, P0 and P1
  double p0[3] = {1.0, 0.0, 0.0};
  double p1[3] = {0.0, 1.0, 0.0};

  vtkSmartPointer<vtkLineSource> lineSource =
      vtkSmartPointer<vtkLineSource>::New();
  lineSource->SetPoint1(p0);
  lineSource->SetPoint2(p1);
  lineSource->Update();

  //Create a mapper and actor
  vtkSmartPointer<vtkPolyDataMapper> mapper =
      vtkSmartPointer<vtkPolyDataMapper>::New();
  mapper->SetInputConnection(lineSource->GetOutputPort());
  vtkSmartPointer<vtkActor> actor =
      vtkSmartPointer<vtkActor>::New();
  actor->SetMapper(mapper);

  //Create a renderer, render window, 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);

  //Add the actor to the scene
  renderer->AddActor(actor);

  //Render and interact
  renderWindow->Render();
  renderWindowInteractor->Start();

*But, when I change these two points as*

double p0[3] = {10.0, 0.0, 0.0};
  double p1[3] = {0.0, 10.0, 0.0};

The line doesn't change.

Could Anyone tell me what's the problem?
I want to draw a line in display coordinate.

Thanks
Best
Erkang
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