html2pdf Fiddle

HTML

<script src="https://rawgit.com/eKoopmans/html2pdf/master/dist/html2pdf.bundle.min.js"></script>
<script src="https://cdn.jsdelivr.net/npm/hanzi-writer@3.2.0/dist/index.cjs.min.js"></script>
<div id="test1"></div>
<div id="test2"></div>

CSS

html, body {
  margin: 0;
  padding: 0;
}

div {
  position: absolute;
  transform-origin: left top;
}

canvas {
  width: 60px;
  height: 60px;
}

#test1 {
  left: 0;
  transform: scale(2);
}

#test2 {
  left: 50%;
  zoom: 200%;
}

JavaScript

const dpr = window.devicePixelRatio || window.webkitDevicePixelRatio || window.mozDevicePixelRatio || 1;
const chineseSize = 60
const scale = 2

HanziWriter.create($('#test1')[0], '龍', {
  renderer: 'canvas',
  width: chineseSize * dpr * scale,
  height: chineseSize * dpr * scale,
  padding: 2
});


HanziWriter.create($('#test2')[0], '龍', {
  renderer: 'canvas',
  width: chineseSize * dpr * scale,
  height: chineseSize * dpr * scale,
  padding: 2
});