[echarts] How to prevent the tooltip from being covered by the outer container

// 手动设置柱状图每一项的tooltip时，默认右下角进行显示，防止被容器遮盖，同时避免气泡遮住图表内
    echartOptions.tooltip.position = function (point, params, dom, rect, size) {
    
    
      // point 为默认的 tooltip 位置，即在鼠标位置上方
      const x = Math.max(point[0], size.viewSize[0] - dom.offsetWidth);
      const y = Math.max(point[1], size.viewSize[1] - dom.offsetHeight);
      return [x, y];
    };