Help with VTK + Qt: DICOM Application Crashes After Scrolling First Slice

[xava]

Hello Qt community,

I am integrating VTK with a Qt application to load and display DICOM series, but I'm facing an issue where the program crashes after displaying the first slice of a DICOM series. The application seems to work for a short while, displaying the DICOM images, but crashes shortly after showing the first slice.

Here is the output I get before the crash:

13:21:16: Starte appVTKQTIntegration.exe...
QML debugging is enabled. Only use this in a safe environment.
Slicer: Min = 0, Max = 431
MoveSliceForward::Slice = 1
13:21:36: Der Prozess ist abgestürzt.

I am using the following example from VTK for reading and displaying DICOM series: VTK Read DICOM Series Example. My application is integrated with Qt and QML, and I use vtkGenericOpenGLRenderWindow for rendering. However, the application crashes after the first slice is displayed.

Could anyone help me identify what might be causing the crash? Here’s the relevant code where I initialize the VTK pipeline and load DICOM files:

VTKRendererItem::initializeVTK Method

QQuickVTKItem::vtkUserData VTKRendererItem::initializeVTK(vtkRenderWindow *renderWindow) {
    if (!renderWindow) {
        qWarning() << "Invalid render window!";
        return nullptr;
    }

    m_RenderWindow = vtkGenericOpenGLRenderWindow::SafeDownCast(renderWindow);
    m_Renderer = vtkSmartPointer<vtkRenderer>::New();
    renderWindow->AddRenderer(m_Renderer);

    m_Transform = vtkSmartPointer<vtkTransform>::New();
    m_Actor = vtkSmartPointer<vtkActor>::New();

    // Create interaction class
    m_Interaction = new VTKInteraction(m_Actor, m_Transform, m_RenderWindow);

    emit signalVtkItemInitialized();

    return nullptr;
}

VTKRendererItem::loadFolder Method

void VTKRendererItem::loadFolder(const QString &folderPath) {
    std::string inputFoldername = folderPath.toStdString();

    // Read all the DICOM files in the specified directory.
    vtkNew<vtkDICOMImageReader> reader;
    reader->SetDirectoryName(inputFoldername.c_str());
    reader->Update();

    vtkNew<vtkImageViewer2> imageViewer;
    imageViewer->SetInputConnection(reader->GetOutputPort());

    if (m_Interaction) {
        m_Interaction->visualizeSliceData(imageViewer);
    }
}

VTKInteraction::visualizeSliceData Method

void VTKInteraction::visualizeSliceData(vtkSmartPointer<vtkImageViewer2> imageViewer) {
    if (!m_RenderWindow) {
        qWarning() << "visualizeSliceData: No valid render window!";
        return;
    }

    // Removed slice and usage text actors for simplicity

    if (m_RenderWindow) {
        m_RenderWindow->MakeCurrent();
    }

    imageViewer->SetRenderWindow(m_RenderWindow);

    vtkRenderer *viewerRenderer = imageViewer->GetRenderer();
    // viewerRenderer->AddActor2D(sliceTextActor); // Commented out
    // viewerRenderer->AddActor2D(usageTextActor); // Commented out

    vtkRenderWindowInteractor *renderWindowInteractor = m_RenderWindow->GetInteractor(); // output: QVTKInteractor cannot control the event loop.
    vtkNew<myVtkInteractorStyleImage> myInteractorStyle;
    myInteractorStyle->SetImageViewer(imageViewer);
    // myInteractorStyle->SetStatusMapper(sliceTextMapper); // Commented out

    imageViewer->SetupInteractor(renderWindowInteractor);
    renderWindowInteractor->SetInteractorStyle(myInteractorStyle);

    imageViewer->Render();
    m_RenderWindow->Render();
    viewerRenderer->ResetCamera();
    imageViewer->Render();
}

Question:

• The program works initially, but after rendering the first slice, it crashes.
• I'm using vtkGenericOpenGLRenderWindow for rendering, and I’ve followed the example provided in the VTK Read DICOM Series Example.
• Any help with resolving this issue would be greatly appreciated.

---

[jsulm]

@xava said in Help with VTK + Qt: DICOM Application Crashes After Scrolling First Slice:

it crashes

What does stack trace in debugger say?

[xava]

@jsulm

The crash happens in InteractorStyleSlices.h, line 76, when calling:

_ImageViewer->SetSlice(_Slice);

with an access violation (0xc0000005).
Here is the stack trace from the debugger:

1   myVtkInteractorStyleImage::MoveSliceForward     InteractorStyleSlices.h        76   0x7ff7aaf6f473  
2   myVtkInteractorStyleImage::OnMouseWheelForward  InteractorStyleSlices.h       129  0x7ff7aaf69a04  
3   vtkInteractorStyle::ProcessEvents              vtkInteractorStyle.cxx        1196 0x7fff492d6fa0  
4   vtkCallbackCommand::Execute                    vtkCallbackCommand.cxx         30   0x7fff42d4acae  
5   vtkSubjectHelper::InvokeEvent                  vtkObject.cxx                  638  0x7fff42f0a0f5  
6   vtkObject::InvokeEvent                         vtkObject.cxx                  807  0x7fff42f07485  
7   QVTKInteractorAdapter::ProcessEvent            QVTKInteractorAdapter.cxx      339  0x7fff3ecd1e1d  
8   QQuickVTKInteractorAdapter::ProcessEvent       QQuickVTKInteractorAdapter.cxx 81   0x7fff76f35a7d  
9   QQuickVTKItem::event lambda operator()         QQuickVTKItem.cxx              583  0x7fff76f37a93  
10  std::invoke                                    type_traits                    1706 0x7fff76f3b6cd  
11  std::_Func_impl_no_alloc::_Do_call             functional                      879  0x7fff76f382cf  
12  std::_Func_class::operator()                   functional                      925  0x7fff76f3edee  
13  QQuickVTKItem::updatePaintNode                 QQuickVTKItem.cxx              325  0x7fff76f37070  
14  QQuickWindowPrivate::updateDirtyNode           qquickwindow.cpp               2271 0x7fff4cab686a  
15  QQuickWindowPrivate::updateDirtyNodes          qquickwindow.cpp               2014 0x7fff4cab552b  
16  QQuickWindowPrivate::syncSceneGraph            qquickwindow.cpp                568  0x7fff4cab44bb  
17  QSGRenderThread::sync                          qsgthreadedrenderloop.cpp       554  0x7fff4d00462d  
18  QSGRenderThread::syncAndRender                 qsgthreadedrenderloop.cpp       719  0x7fff4d003b09  
19  QSGRenderThread::run                           qsgthreadedrenderloop.cpp       979  0x7fff4d002a41  
20  QThreadPrivate::start                          qthread_win.cpp                 273  0x7fff49cfdf90  

[jsulm]

@xava said in Help with VTK + Qt: DICOM Application Crashes After Scrolling First Slice:

myVtkInteractorStyleImage::MoveSliceForward InteractorStyleSlices.h

Check what you're doing in that line