Show Camera inside of a Widget-App

[peter-70]

I have a QMainWindow Class where a function is called:

void MyTest::OnOpenCamera()
{
    this->setVisible(false);
    auto cameraApp = new CameraApp;
    cameraApp->Show(this);
}

In class CameraApp the following code is implemented:

CameraApp::CameraApp()
{
    QCoreApplication::setAttribute(Qt::AA_UseHighDpiPixmaps);
    QZXing::registerQMLTypes();
    NativeHelpers::registerApplicationInstance(this);

    this->LoadQml();
}

CameraApp::~CameraApp()
{
}

void CameraApp::LoadQml()
{
    this->engine.load(QUrl(QStringLiteral("qrc:/qml/camera.qml")));
}

void CameraApp::Show(QWidget* parent)
{
    QObject* topLevel = this->engine.rootObjects().value(0);
    QQuickWindow* window = qobject_cast<QQuickWindow*>(topLevel);
    window->show();
}

Now the camera window is showing indeed, but it's not transparent.

What can I do, to see a normally camera screen inside of my app?
Thank you!

[SGaist]

Hi,

Might be a silly question but why not use QCameraViewfinder ?

[peter-70]

The example is an QZXingLive-example. There is no QCameraViewfinder in use.

Just in main.cpp

int main(int argc, char *argv[])
{
    QCoreApplication::setAttribute(Qt::AA_UseHighDpiPixmaps);
    QGuiApplication app(argc, argv);

    QZXing::registerQMLTypes();

    Application customApp;
    customApp.checkPermissions();

    return app.exec();
}

and then in application.cpp

Application::Application()
{
    //both signals will be connected to the same function for
    //simplicity

    connect(this, &Application::onPermissionsGranted,
            this, &Application::initializeQML);

    connect(this, &Application::onPermissionsDenied,
            this, &Application::initializeQML);

    NativeHelpers::registerApplicationInstance(this);
}

void Application::initializeQML()
{
    engine.load(QUrl(QStringLiteral("qrc:/main.qml")));
}

void Application::checkPermissions()
{
#if defined(Q_OS_ANDROID)
    //intentionally called in the C++ thread since it is blocking and will continue after the check
    qDebug() << "About to request permissions";

        QAndroidJniObject::callStaticMethod<void>("org/ftylitak/qzxing/Utilities",
                                        "requestQZXingPermissions",
                                        "(Landroid/app/Activity;)V",
                                        QtAndroid::androidActivity().object());
    qDebug() << "Permissions granted";
#else
    emit onPermissionsGranted();
#endif //Q_OS_ANDROID
}

Now I wonder, how can I implement this as a library implementation for my app.

[jsulm]

@peter-70 said in Show Camera inside of a Widget-App:

Now the camera window is showing indeed, but it's not transparent.

What is not transparent?
It looks like you want to use a barcode scanner, right?

[peter-70]

Yes, exactly!

When I try to run the code in my app, the qml content is visible, but it has a white background. So I can't see the camera input signal/image

[jsulm]

@peter-70 Does checkPermissions() succeed?

[peter-70]

Yes! The engine.load is called. The qml file can be found. The content of the qml file is drawn, but the background of it, is white and not transparent.

But this is only when I try to run the app, as a lib, from my widget app. If the scanner app runs as standalone app, everything is ok.