Method Execute

Interaction/Image/vtkImageViewer.cxx:88–181

  static vtkImageViewerCallback* New() { return new vtkImageViewerCallback; }

  void Execute(vtkObject* caller, unsigned long event, void* vtkNotUsed(callData)) override
  {
    if (this->IV->GetInput() == nullptr)
    {
      return;
    }

    // Reset

    if (event == vtkCommand::ResetWindowLevelEvent)
    {
      this->IV->GetInputAlgorithm()->UpdateWholeExtent();
      double* range = this->IV->GetInput()->GetScalarRange();
      this->IV->SetColorWindow(range[1] - range[0]);
      this->IV->SetColorLevel(0.5 * (range[1] + range[0]));
      this->IV->Render();
      return;
    }

    // Start

    if (event == vtkCommand::StartWindowLevelEvent)
    {
      this->InitialWindow = this->IV->GetColorWindow();
      this->InitialLevel = this->IV->GetColorLevel();
      return;
    }

    // Adjust the window level here

    vtkInteractorStyleImage* isi = static_cast<vtkInteractorStyleImage*>(caller);

    const int* size = this->IV->GetRenderWindow()->GetSize();
    double window = this->InitialWindow;
    double level = this->InitialLevel;

    // Compute normalized delta

    double dx = 4.0 *
      (isi->GetWindowLevelCurrentPosition()[0] - isi->GetWindowLevelStartPosition()[0]) / size[0];
    double dy = 4.0 *
      (isi->GetWindowLevelStartPosition()[1] - isi->GetWindowLevelCurrentPosition()[1]) / size[1];

    // Scale by current values

    if (fabs(window) > 0.01)
    {
      dx = dx * window;
    }
    else
    {
      dx = dx * (window < 0 ? -0.01 : 0.01);
    }
    if (fabs(level) > 0.01)
    {
      dy = dy * level;
    }
    else