html5 canvas半圆环百分比进度条动画特效

 

 

 

<!DOCTYPE html>
<html>
  <head>
    <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1" />
    <meta http-equiv="content-type" content="text/html;charset=utf-8" />
    <title>动态画一半圆环</title>
  </head>
  <body>
    <div class="ring" style="text-align: center;">
      <canvas id="tutorial" width="125" height="125"></canvas>
      <div class="fraction"><span class="numberOne">95</span></div>
      <span class="title">半圆环</span>
    </div>
    <script>
      let radius = 60; //外环半径
      let thickness = 10; //圆环厚度
      let innerRadius = radius - thickness; //内环半径
      let startAngle = -90; //开始角度
      let endAngle = 180; //结束角度
      let x = 0; //圆心x坐标
      let y = 0; //圆心y坐标
      let canvas = document.getElementById("tutorial");
      canvas.width = 125;
      canvas.height = 125;

      let ctx = canvas.getContext("2d");
      ctx.translate(canvas.width / 2, canvas.height / 2); //将绘图原点移到画布中央
      ctx.rotate(angle2Radian(225)); //将画布旋转225度
      ctx.fillStyle = "#eee"; //初始填充颜色
      renderRing(startAngle, endAngle);

      //渲染函数
      function renderRing(startAngle, endAngle) {
        ctx.beginPath();

        //绘制外环
        ctx.arc(x, y, radius, angle2Radian(startAngle), angle2Radian(endAngle));

        //计算外环与内环第一个连接处的中心坐标
        let oneCtrlPoint = calcRingPoint(
          x,
          y,
          innerRadius + thickness / 2,
          endAngle
        );

        //绘制外环与内环第一个连接处的圆环
        ctx.arc(
          oneCtrlPoint.x,
          oneCtrlPoint.y,
          thickness / 2,
          angle2Radian(-90),
          angle2Radian(270)
        );

        // //绘制内环
        ctx.arc(
          x,
          y,
          innerRadius,
          angle2Radian(endAngle),
          angle2Radian(startAngle),
          true
        );

        //计算外环与内环第二个连接处的中心坐标
        let twoCtrlPoint = calcRingPoint(
          x,
          y,
          innerRadius + thickness / 2,
          startAngle
        );

        //绘制外环与内环第二个连接处的圆环
        ctx.arc(
          twoCtrlPoint.x,
          twoCtrlPoint.y,
          thickness / 2,
          angle2Radian(-90),
          angle2Radian(270)
        );

        ctx.fill();
        // ctx.stroke()
      }

      //计算圆环上点的坐标
      function calcRingPoint(x, y, radius, angle) {
        let res = {};
        res.x = x + radius * Math.cos((angle * Math.PI) / 180);
        res.y = y + radius * Math.sin((angle * Math.PI) / 180);
        return res;
      }

      //弧度转角度
      function radian2Angle(radian) {
        return (180 * radian) / Math.PI;
      }

      //角度转弧度
      function angle2Radian(angle) {
        return (angle * Math.PI) / 180;
      }

      //进度条颜色
      var lingrad = ctx.createLinearGradient(0, 0, 150, 0);
      lingrad.addColorStop(0, "#00ABEB");
      lingrad.addColorStop(1, "#fff");
      ctx.fillStyle = lingrad;

      //开始绘画
      let tempAngle = startAngle;
      let total = 1000; //总分
      let now = 950; //当前分数
      let percent = now / total; //百分比
      let twoEndAngle = percent * 270 + startAngle;
      let step = (twoEndAngle - startAngle) / 80;
      let numberSpan = document.querySelector(".numberOne");
      let inter = setInterval(() => {
        if (tempAngle > twoEndAngle) {
          clearInterval(inter);
        } else {
          numberSpan.innerText = percent * 100;
          tempAngle += step;
        }
        renderRing(startAngle, tempAngle);
      }, 20);
    </script>
  </body>
</html>

 

vue中使用圆环可以直接使用element-ui组件库    elementui地址 ：https://element.eleme.cn/#/zh-CN/component/progress

 

 

posted @ 2020-12-21 17:53  静水思流  阅读(1006)  评论(0)  编辑  收藏  举报