Canvas 获取文本宽度使用ctx.measureText

 //创建画布
  ctx.fillStyle = '#fff'
  ctx.fillRect(0, 0, this.config.maxWidth, this.config.maxHeight)
 //获取宽度 
  var txt='今天天气很好'
  var wid_1 = ctx.measureText(txt).width
  console.log(wid_1, 'wid_1')
 
 //打印   144 "wid_1"