Splash window for Qt, replacing QSplashScreen

This SplashWindow class can be used instead of QSplashScreen in applications using QGuiApplication instead of QApplication. It needs only the gui module, but not the widgets module as QSplashScreen, so it may be useful in QML apps.

It is derived from the Raster Window Qt example code.

• close after a fixed amount of time:

    SplashWindow splash;
    splash.show();
    QTimer::singleShot(2500, &splash, SLOT(close()));

• close when another window is shown:

    SplashWindow splash;
    splash.show();
    QQuickView *view = new QQuickView;
    splash.finish(view);
    view->show();

view may be an instance of any QWindow derived class (like QQuickView)

Since the splash screen is typically displayed before the event loop has started running, it is necessary to periodically call QCoreApplication::processEvents().

You may also call splash.close() after completing the application initialization. A new method centerInScreen(QScreen *s) has been added to control the positioning of the splash window.