Method prepareForTopLevelChange

src/gui/SpectrumWidget.cpp:1153–1173

}

void SpectrumWidget::prepareForTopLevelChange()
{
#ifdef AETHER_GPU_SPECTRUM
    // QRhiWidget registers a cleanup callback with the current top-level
    // backing-store QRhi. Direct splitter/floating-window reparenting can miss
    // Qt's internal notification, leaving the old QRhi with a stale callback;
    // when that QRhi is later torn down, runCleanup() fires against a stale
    // QRhiWidgetPrivate and crashes during deferred event delivery (#2495).
    //
    // QEvent::WindowAboutToChangeInternal is cross-platform Qt machinery —
    // QRhiWidgetPrivate deregisters the callback the same way on Metal,
    // D3D/Vulkan and OpenGL — so this must fire on every GPU platform, not
    // just macOS. It was originally gated to Q_OS_MAC because #2495 was first
    // reproduced there; leaving Windows ungated let the identical crash slip
    // through on connect-time multi-panadapter restore (#3714). The send must
    // happen exactly once, before the reparent (refreshAfterReparent must not
    // re-send it — see PanadapterStack.cpp).
    QEvent event(QEvent::WindowAboutToChangeInternal);
    QCoreApplication::sendEvent(this, &event);
#endif
}

void SpectrumWidget::prepareForShutdown()
{