[Interest] Opening Qt/Qml window inside host app

Nuno Santos nunosantos at imaginando.pt
Wed Dec 3 21:13:26 CET 2014


I cannot tell you exactly how it is working. That was what I supposed as well. I even considered not calling exec and call app->processEvents(); on a regular basis somehow. This is what I have:

IVstWrapper::IVstWrapper(audioMasterCallback audioMaster) : AudioEffectX (audioMaster, kNumPrograms, kNumParams)
    int argc=0;

    settings = new IBasicSynthSettings(this);
    wrapper = new IBasicSynthWrapper(this);


    app = new QGuiApplication(argc, 0);
    engine = new QQmlApplicationEngine(app);

    engine->rootContext()->setContextProperty("settings", settings);
    engine->rootContext()->setContextProperty("wrapper", wrapper);


    if (audioMaster)


Like this, qml is responding to events and I can communicate with the C++ core of the synth from the GUI.

I had to switch context and work on other project in the meanwhile. But next week I will get back to this again and maybe I will be faced with any sort of limitation (hopefully not). 

Right now, I have just tried this approach on Mac.

If anyone knows any limitation on this approach, I would be glad to know about it or better understand it. If there is an even better and solid solution, i’m looking forward to know about it.



> On 10/11/2014, at 08:18, Tim Blechmann <tim at klingt.org> wrote:
>> In general, for VST2 your implementation of AEffEditor::open() should
>> create the thread creating the application object and invoking
>> exec(). That is the latest point you can use before it has to be
>> created.
> out of curiosity: doesn't QApplication::exec have to be created from the
> main thread? in my experience, it is better to call sendPostedEvents()
> from the main thread.
> tim
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