Integrating a WPF Control into Win32 Program and Sizing According to Parent HWND (Which is a QWidget)

Question

I am currently developing a WPF control which I intend to frame within a Win32 program. My parent window within this context is a QWidget. I have been successful with the integration per se, but I am facing a concern: the WPF control does not automatically resize itself according to the changes made to the parent HWND.

A key clarifying detail is that I want the WPF control to adjust in size automatically when the QSize of the parent QWidget is modified, maintaining a good degree of responsiveness.

Here are some code snippets to present the situation:

void CommonPlugin::AdjustWPFWnd(HWND parent, int x, int y, int width, int height, Object ^ object)
{
    if (static_cast<System::Windows::Interop::HwndSourceParameters ^>(m_sourceParams) == nullptr)
    {
        m_sourceParams = gcnew System::Windows::Interop::HwndSourceParameters("WPF");
        m_sourceParams->PositionX = x;
        m_sourceParams->PositionY = y;
        m_sourceParams->Height = height;
        m_sourceParams->Width = width;
        m_sourceParams->WindowName = "WPF Window";
        m_sourceParams->ParentWindow = IntPtr(parent);
        m_sourceParams->UsesPerPixelOpacity = true;
        m_sourceParams->WindowStyle = 0x10000000L | 0x40000000L; // WS_VISIBLE | WS_CHILD
        m_sourceParams->RestoreFocusMode = System::Windows::Input::RestoreFocusMode::None;
        m_sourceParams->AcquireHwndFocusInMenuMode = false;
        System::Windows::Interop::HwndSourceParameters ^ sourceParams = m_sourceParams;

        m_source = gcnew System::Windows::Interop::HwndSource(*sourceParams);
        if (static_cast<System::Windows::Interop::HwndSource ^>(m_source) == nullptr)
            return;
        m_source->CompositionTarget->BackgroundColor = System::Windows::Media::Brushes::White->Color;
        m_source->RootVisual = (System::Windows::Media::Visual ^) object;
    }
    else
    {
        m_context->Reset();
        m_context->PreferredSize = QSize(width, height);
        qDebug() << __FUNCTION__ << " width:" << width << " height:" << height;
        m_sourceParams->SetSize(width, height);
        m_sourceParams->RestoreFocusMode = System::Windows::Input::RestoreFocusMode::None;
        m_sourceParams->AcquireHwndFocusInMenuMode = false;
        System::Windows::FrameworkElement ^ fe =
            dynamic_cast<System::Windows::FrameworkElement ^>(m_source->RootVisual);
        if (fe != nullptr)
        {
            fe->Width = width;
            fe->Height = height;
            fe->InvalidateMeasure();
            fe->InvalidateArrange();
            fe->Measure(System::Windows::Size(width, height));
            fe->Arrange(System::Windows::Rect(0, 0, width, height));
        }
        HWND hwnd = (HWND)m_source->Handle.ToPointer();
    }
}

void CommonPlugin::onResizeEvent(int width, int height)
{
    qDebug() << __FUNCTION__ << " width:" << width << " height:" << height;
    if (m_w)
    {
        AdjustWPFWnd((HWND)m_w->winId(), 0, 0, width, height - 10, m_gccontext->ViewerContent);
    }
}

I think I could maybe handle this with events - setting it up in such a way that when a resize event takes place in the QWidget, the integrated WPF control will adjust in size accordingly. Still, I’m unsure of the most effective and efficient way to implement this.

How can I best to approach a solution to this problem?

I was expecting the WPF control to adjust its dimensions in response to changes in QWidget’s size, maintaining consistency in their dimensions.

However, what I encountered was different. The WPF control size did not seem to change at all, remaining in its initial dimensions even after resizing the QWidget. Alternatively, it did not resize properly, leading to either overstretching or compressing which was unproportional with the QWidget dimensions.

I’d appreciate some guidance on whether my approach was correct or not, and any possible improvements I could make.