function hStrokeWidth() {
  const selector = $('#weight-select');
  const yiGm = res.glyphModels[selector.val()]['U+4E00'];
  if (!yiGm) 
    throw Error('The character U+4E00 must be included in the glyph models.');
  const yiGlyph = yiGm.restore(
    ModelFilters.weightAdjustment(globalParams.weight)
  );
  const hStrokeWidth = (yiGlyph[0][0].y - yiGlyph[0][1].y)*0.8;
  return hStrokeWidth;
}
Estimate the horizontal stroke width @returns { number }