Updates the layout for the graphics within this scene.

def autoLayout(self, size=None):
        """
        Updates the layout for the graphics within this scene.
        """
        if size is None:
            size = self._view.size()
        
        self.setSceneRect(0, 0, size.width(), size.height())
        for item in self.items():
            if isinstance(item, XWalkthroughGraphic):
                item.autoLayout(size)