如何使用convasjs将饼图转换为图像

<canvas id="chartCanvas" width="400" height="400"></canvas>

var chart = new CanvasJS.Chart("chartCanvas", {
  // 饼图的配置选项
  data: [{
    type: "pie",
    dataPoints: [
      { label: "苹果", y: 30 },
      { label: "香蕉", y: 20 },
      { label: "橙子", y: 25 },
      { label: "葡萄", y: 15 },
      { label: "西瓜", y: 10 }
    ]
  }]
});

chart.render();

var canvas = document.getElementById("chartCanvas");
var image = canvas.toDataURL("image/png");

// 将图像显示在页面上
var imgElement = document.createElement("img");
imgElement.src = image;
document.body.appendChild(imgElement);

// 或者将图像保存为文件
var link = document.createElement("a");
link.href = image;
link.download = "chart.png";
link.click();