) {
                        var point = api.coord([0, 0]);
                        point[0] += barLayout[index].offsetCenter;
                        point[1] = api.getHeight() - 20;

                        return {
                            position: point,
                            name: serIdx,
                            type: 'circle',
                            shape: {
                                cx: 0, cy: 0, r: 10
                            },
                            style: {
       