Canvas/38_canvas_文字度量.html

<!DOCTYPE html>
<html>

<head>
  <meta charset="utf-8" />
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <title>Page Title</title>
  <meta name="viewport" content="width=device-width, initial-scale=1">
</head>

<body>
  <canvas id="myCanvas" style="border:1px solid red;">
    当前浏览器不支持canvas，请更换浏览器后再试
  </canvas>
  <script>
    window.onload = function () {
      var canvas = document.getElementById('myCanvas')

      canvas.width = 1200
      canvas.height = 800

      var ctx = canvas.getContext('2d')

      ctx.font = 'bold 40px Arial'
      ctx.fillStyle = 'blue'

      ctx.fillText('你好', 40, 40)

      var text = ctx.measureText('你好')
      console.log(text)
      var textW = text.width // 暂时只能度量宽度，并没有高度
      ctx.fillText('宽度为:' + textW, 40, 200)
    }
  </script>
</body>

</html>