# vtk app CPU usage 100%.

**URL:** https://discourse.vtk.org/t/vtk-app-cpu-usage-100/6894
**Category:** Support
**Created:** [October 15, 2021, 9:37am UTC](https://discourse.vtk.org/t/vtk-app-cpu-usage-100/6894 "2021-10-15T09:37:20Z")
**Posts on this page:** 1
**Page:** 1

<div class="post-metadata">

### Author: ![BeyondXinXin](https://discourse.vtk.org/user_avatar/discourse.vtk.org/beyondxinxin/32/3271_2.png) [@BeyondXinXin](https://discourse.vtk.org/u/BeyondXinXin)
#### Post date: [October 15, 2021, 9:37am UTC](https://discourse.vtk.org/t/vtk-app-cpu-usage-100/6894/1 "2021-10-15T09:37:21Z")

</div>

After modify `vtkCubeAxesActor` `TitleText` colour,CPU usage 100%.

# Set the uniform color and everything is normal

```cpp
class Callback : public vtkCommand
{
public:
    vtkTypeMacro(Callback, vtkCommand);
    static Callback *New();
    void Execute(vtkObject *vtkNotUsed(caller), unsigned long vtkNotUsed(eventId),
                 void *vtkNotUsed(callData));
    vtkRenderWindow *window_;
};
vtkStandardNewMacro(Callback);

void Callback::Execute(vtkObject *vtkNotUsed(caller),
                       unsigned long vtkNotUsed(eventId),
                       void *vtkNotUsed(callData))
{
    window_->Render();
}

int main(int, char *[])
{
    vtkNew<vtkRenderer> renderer;
    vtkNew<vtkCubeAxesActor> cubeAxesActor;
    cubeAxesActor->SetCamera(renderer->GetActiveCamera());
    cubeAxesActor->GetTitleTextProperty(0)->SetColor(0.0, 1.0, 0.0);
    cubeAxesActor->GetTitleTextProperty(1)->SetColor(0.0, 1.0, 0.0);
    cubeAxesActor->GetTitleTextProperty(2)->SetColor(0.0, 1.0, 0.0);
    renderer->AddActor(cubeAxesActor);
    renderer->ResetCamera();
    vtkNew<vtkRenderWindow> renderWindow;
    renderWindow->AddRenderer(renderer);
    renderWindow->SetSize(640, 480);
    vtkNew<vtkRenderWindowInteractor> renderWindowInteractor;
    renderWindowInteractor->SetRenderWindow(renderWindow);
    renderWindow->Render();
    renderer->GetActiveCamera()->Zoom(0.8);
    vtkNew<Callback> callback;
    callback->window_ = renderWindow;
    renderWindowInteractor->CreateRepeatingTimer(10);
    renderWindowInteractor->AddObserver(vtkCommand::TimerEvent, callback);
    renderWindowInteractor->Start();
    return EXIT_SUCCESS;
}

```

 ![image](https://discourse.vtk.org/uploads/default/original/2X/2/2f931c4ca498a6e13745cc42f81c294a39a96b79.png)

# Set different colors,CPU usage 100%.

```cpp
class Callback : public vtkCommand
{
public:
    vtkTypeMacro(Callback, vtkCommand);
    static Callback *New();
    void Execute(vtkObject *vtkNotUsed(caller), unsigned long vtkNotUsed(eventId),
                 void *vtkNotUsed(callData));
    vtkRenderWindow *window_;
};
vtkStandardNewMacro(Callback);

void Callback::Execute(vtkObject *vtkNotUsed(caller),
                       unsigned long vtkNotUsed(eventId),
                       void *vtkNotUsed(callData))
{
    window_->Render();
}

int main(int, char *[])
{
    vtkNew<vtkRenderer> renderer;
    vtkNew<vtkCubeAxesActor> cubeAxesActor;
    cubeAxesActor->SetCamera(renderer->GetActiveCamera());
    cubeAxesActor->GetTitleTextProperty(1)->SetColor(0.0, 1.0, 0.0);
    renderer->AddActor(cubeAxesActor);
    renderer->ResetCamera();
    vtkNew<vtkRenderWindow> renderWindow;
    renderWindow->AddRenderer(renderer);
    renderWindow->SetSize(640, 480);
    vtkNew<vtkRenderWindowInteractor> renderWindowInteractor;
    renderWindowInteractor->SetRenderWindow(renderWindow);
    renderWindow->Render();
    renderer->GetActiveCamera()->Zoom(0.8);
    vtkNew<Callback> callback;
    callback->window_ = renderWindow;
    renderWindowInteractor->CreateRepeatingTimer(10);
    renderWindowInteractor->AddObserver(vtkCommand::TimerEvent, callback);
    renderWindowInteractor->Start();
    return EXIT_SUCCESS;
}

```

 ![image](https://discourse.vtk.org/uploads/default/original/2X/0/0fc86a63178c929875bb93b6ba3d2d85a4e15295.png)

# Comment out these three lines. Everything is normal

[https://gitlab.kitware.com/vtk/vtk/-/blob/master/Rendering/Annotation/vtkCubeAxesActor.cxx#L1668](https://gitlab.kitware.com/vtk/vtk/-/blob/master/Rendering/Annotation/vtkCubeAxesActor.cxx#L1668)

 ![image](https://discourse.vtk.org/uploads/default/original/2X/d/d5ac384b90732a89e39b2d7b0d436714f37254b5.png)