void cv::viz::vtkVizInteractorStyle::OnKeyDown()

in modules/viz/src/vtk/vtkVizInteractorStyle.cpp [386:498]
99 lines of code
54 McCabe index (conditional complexity)

void cv::viz::vtkVizInteractorStyle::OnKeyDown()
{
    FindPokedRenderer(Interactor->GetEventPosition()[0], Interactor->GetEventPosition()[1]);

    String key(Interactor->GetKeySym());
    if (key.find("XF86ZoomIn") != String::npos)
        zoomIn();
    else if (key.find("XF86ZoomOut") != String::npos)
        zoomOut();
    else if (key.find("F5") != String::npos)
    {
        FlyMode = !FlyMode;
        std::cout << (FlyMode ? "Fly mode: on" : "Fly mode: off") << std::endl;
    }

    // Save the initial windows width/height
    if (win_size_[0] == -1 || win_size_[1] == -1)
        win_size_ = Vec2i(Interactor->GetRenderWindow()->GetSize());

    switch (Interactor->GetKeyCode())
    {
    case 'a': case 'A' : KeysDown |=16; break;
    case 'z': case 'Z' : KeysDown |=32; break;
    case 'h': case 'H' : printHelp();   break;
    case 'p': case 'P' : setRepresentationToPoints(); break;
    case 'k': case 'K' : exportScene(); break;
    case 'j': case 'J' : saveScreenshot(cv::format("screenshot-%d.png", (unsigned int)time(0))); break;
    case 'c': case 'C' : printCameraParams(); break;
    case '=':           zoomIn();            break;
    case 43:        // KEY_PLUS
    {
        if (FlyMode)
            break;
        if (Interactor->GetAltKey())
            zoomIn();
        else
            changePointsSize(+1.f);
        break;
    }
    case 45:        // KEY_MINUS
    {
        if (FlyMode)
            break;
        if (Interactor->GetAltKey())
            zoomOut();
        else
           changePointsSize(-1.f);
        break;
    }
        // Switch between maximize and original window size
    case 'f': case 'F':
    {
        if (Interactor->GetAltKey())
            toggleFullScreen();
        break;
    }
        // 's'/'S' w/out ALT
    case 's': case 'S':
    {
        if (Interactor->GetAltKey())
            toggleStereo();
        break;
    }

    case 'o': case 'O':
    {
        vtkSmartPointer<vtkCamera> cam = CurrentRenderer->GetActiveCamera();
        cam->SetParallelProjection(!cam->GetParallelProjection());
        Interactor->Render();
        break;
    }

    // Overwrite the camera reset
    case 'r': case 'R':
    {
        if (Interactor->GetAltKey())
            resetViewerPose();
        break;
    }
    case 'q': case 'Q':
        Interactor->ExitCallback(); return;
    default:
        Superclass::OnKeyDown(); break;
    }

    KeyboardEvent event(KeyboardEvent::KEY_DOWN, Interactor->GetKeySym(), Interactor->GetKeyCode(), getModifiers());
    if (keyboardCallback_)
        keyboardCallback_(event, keyboard_callback_cookie_);

    if (FlyMode && (KeysDown & (32+16)) == (32+16))
    {
        if (State == VTKIS_FORWARDFLY || State == VTKIS_REVERSEFLY)
            StopState();
    }
    else if (FlyMode && (KeysDown & 32) == 32)
    {
        if (State == VTKIS_FORWARDFLY)
            StopState();

        if (State == VTKIS_NONE)
            StartState(VTKIS_REVERSEFLY);
    }
    else if (FlyMode && (KeysDown & 16) == 16)
    {
        if (State == VTKIS_REVERSEFLY)
            StopState();

        if (State == VTKIS_NONE)
            StartState(VTKIS_FORWARDFLY);
    }

    Interactor->Render();
}