Detailed Description

The QX11EmbedContainer class provides an XEmbed container widget.

XEmbed is an X11 protocol that supports the embedding of a widget from one application into another application.

An XEmbed container is the graphical location that embeds an external client widget. A client widget is a window that is embedded into a container.

When a widget has been embedded and the container receives tab focus, focus is passed on to the widget. When the widget reaches the end of its focus chain, focus is passed back to the container. Window activation, accelerator support, modality and drag and drop (XDND) are also handled.

QX11EmbedContainer is commonly used for writing panels or toolbars that hold applets, or for swallowing X11 applications. When writing a panel application, one container widget is created on the toolbar, and it can then either swallow another widget using embed(), or allow an XEmbed widget to be embedded into itself. The container's X11 window ID, which is retrieved with winId(), must then be known to the client widget. After embedding, the client's window ID can be retrieved with clientWinId().

In the following example, a container widget is created as the main widget. It then invokes an application called "playmovie", passing its window ID as a command line argument. The "playmovie" program is an XEmbed client widget. The widget embeds itself into the container using the container's window ID.

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);

    if (app.arguments().count() != 2) {
        qFatal("Error - expected executable path as argument");
        return 1;
    }

    QX11EmbedContainer container;
    container.show();

    QProcess process(&container);
    QString executable(app.arguments()[1]);
    QStringList arguments;
    arguments << QString::number(container.winId());
    process.start(executable, arguments);

    int status = app.exec();
    process.close();
    return status;
}

When the client widget is embedded, the container emits the signal clientIsEmbedded(). The signal clientClosed() is emitted when a widget is closed.

It is possible for QX11EmbedContainer to embed XEmbed widgets from toolkits other than Qt, such as GTK+. Arbitrary (non-XEmbed) X11 widgets can also be embedded, but the XEmbed-specific features such as window activation and focus handling are then lost.

The GTK+ equivalent of QX11EmbedContainer is GtkSocket. The corresponding KDE 3 widget is called QXEmbed.