html5 canvas简单封装一个echarts实现不了的饼图

function drawCircle(canvasId, option) {    const color_arr = option.color    let data_arr = option.data    const pi2 = Math.PI * 2;    let canvas = document.getElementById(canvasId);    let c = canvas.getContext("2d");    let startAgl = 0;    let agl;    let sum = 0;    const cW = canvas.width;    const cH = canvas.height;    for (let item of data_arr) {      sum += item.value * 1.0    }    data_arr = data_arr.map((v, i) => {      return {        name: v.name,        value: (v.value) * 1.0 / sum      }    })    for (let i = 0; i < data_arr.length; i++) {      //绘制饼图      let min = (cW > cH ? cH : cW); //获取canvas宽高的最小值      agl = data_arr[i].value * pi2 + startAgl; //终点      c.strokeStyle = color_arr[i];      c.lineWidth = data_arr[i].value * min * 0.3; // 线的粗细      c.beginPath();      c.arc(cW / 2, cH / 2, min * 0.3, startAgl, agl, false); //画圆      c.stroke();      c.closePath();      startAgl = agl;      //绘制图例      c.fillStyle = color_arr[i];      c.fillRect(cW * 0.8, 50 + 18 * i, 16, 16);      c.fillText(data_arr[i].name, cW * 0.8 + 20, 62 + 18 * i);    }  }

let color = ['#0580F2', '#FAA732', '#E1575D', '#8B73CC', '#8CD123', '#4B53BA', '#429588'];  let option = {    color: color,    data: [      { name: '20', value: '20' },      { name: '30', value: '30' },      { name: '40', value: '40' },      { name: '50', value: '50' },      { name: '60', value: '60' },    ]  }  drawCircle('myCanvas', option)