Returns selection bounding box or visible area

def _get_print_area(self):
        """Returns selection bounding box or visible area"""

        # Get print area from current selection
        selection = self.main_window.grid.selection
        print_area = selection.get_bbox()

        # If there is no selection use the visible area on the screen
        if print_area is None:
            print_area = self.main_window.grid.actions.get_visible_area()

        return print_area