Method OnMiddleButtonDown

Interaction/Widgets/vtkLineWidget.cxx:672–728

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void vtkLineWidget::OnMiddleButtonDown()
{
  int forward = 0;

  int X = this->Interactor->GetEventPosition()[0];
  int Y = this->Interactor->GetEventPosition()[1];

  // Okay, make sure that the pick is in the current renderer
  if (!this->CurrentRenderer || !this->CurrentRenderer->IsInViewport(X, Y))
  {
    this->State = vtkLineWidget::Outside;
    return;
  }

  // Okay, we can process this. Try to pick handles first;
  // if no handles picked, then pick the bounding box.
  vtkAssemblyPath* path = this->GetAssemblyPath(X, Y, 0., this->HandlePicker);

  if (path != nullptr)
  {
    this->EventCallbackCommand->SetAbortFlag(1);
    this->StartInteraction();
    this->InvokeEvent(vtkCommand::StartInteractionEvent, nullptr);
    this->State = vtkLineWidget::MovingLine;
    this->HighlightHandles(1);
    this->HighlightLine(1);
    this->EnablePointWidget();
    forward = this->ForwardEvent(vtkCommand::LeftButtonPressEvent);
  }
  else
  {
    path = this->GetAssemblyPath(X, Y, 0., this->LinePicker);

    if (path != nullptr)
    {
      this->EventCallbackCommand->SetAbortFlag(1);
      this->StartInteraction();
      this->InvokeEvent(vtkCommand::StartInteractionEvent, nullptr);
      // The highlight methods set the LastPickPosition, so they are ordered
      this->HighlightHandles(1);
      this->HighlightLine(1);
      this->State = vtkLineWidget::MovingLine;
      this->EnablePointWidget();
      forward = this->ForwardEvent(vtkCommand::LeftButtonPressEvent);
    }
    else
    {
      this->State = vtkLineWidget::Outside;
      return;
    }
  }

  if (!forward)
  {
    this->Interactor->Render();
  }
}