如何显示绘制的图形的值

Question

如何获取绘制在显示图上方的图的值？

var viewModel = observableModule.fromObject({
    categoricalSource: [
      { Country: "Germany", Amount: 15, SecondVal: 14, ThirdVal: 24},
      { Country: "France", Amount: 13, SecondVal: 23, ThirdVal: 25 },
      { Country: "Bulgaria", Amount: 24, SecondVal: 17, ThirdVal: 23 },
      { Country: "Spain", Amount: 11, SecondVal: 19, ThirdVal: 24 },
      { Country: "USA", Amount: 18, SecondVal: 8, ThirdVal: 21 }
    ],
}

应绘制图形，并在顶部显示图形的值。