这个是我用canvas 画出来的 下面是代码片段 https://developers.weixin.qq.com/s/UI8SbKmj7wmS 

var ctx = canvas.getContext('2d')
  var centerX = width / 2;
  var centerY = height / 2;
  var rad = Math.PI * 2 / 100; //Math.PI = 180°,此处是吧360°分成100份
  var speed = 30;
  console.log(width, height)
  function dot() {
    ctx.beginPath()
    ctx.arc(68, 68, 30, 0, 2 * Math.PI)
    ctx.strokeStyle ='blue'
    ctx.fill()
  }
  dot()