Gtk.Widget.prototype.get_child_requisition

function get_child_requisition():void {
    // Gjs wrapper for gtk_widget_get_child_requisition()
}

This function is only for use in widget implementations. Obtains widget->requisition, unless someone has forced a particular geometry on the widget (e.g. with Gtk.set_size_request), in which case it returns that geometry instead of the widget's requisition.

This function differs from Gtk.size_request in that it retrieves the last size request value from widget->requisition, while Gtk.size_request actually calls the "size_request" method on widget to compute the size request and fill in widget->requisition, and only then returns widget->requisition.

Because this function does not call the "size_request" method, it can only be used when you know that widget->requisition is up-to-date, that is, Gtk.size_request has been called since the last time a resize was queued. In general, only container implementations have this information; applications should use Gtk.size_request.