modernizr/feature-detects/css/subpixelfont.js

Modernizr is a JavaScript library that detects HTML5 and CSS3 features in the user’s browser.

/*!
{
  "name": "CSS Subpixel Fonts",
  "property": "subpixelfont",
  "tags": ["css"],
  "authors": [
    "@derSchepp",
    "@gerritvanaaken",
    "@rodneyrehm",
    "@yatil",
    "@ryanseddon"
  ],
  "notes": [{
    "name": "Origin Test",
    "href": "https://github.com/gerritvanaaken/subpixeldetect"
  }]
}
!*/
define(['Modernizr', 'testStyles'], function( Modernizr, testStyles ) {
  /*
   * (to infer if GDI or DirectWrite is used on Windows)
   */
  testStyles(
    '#modernizr{position: absolute; top: -10em; visibility:hidden; font: normal 10px arial;}#subpixel{float: left; font-size: 33.3333%;}',
  function( elem ) {
    var subpixel = elem.firstChild;
    subpixel.innerHTML = 'This is a text written in Arial';
    Modernizr.addTest('subpixelfont', window.getComputedStyle ?
      window.getComputedStyle(subpixel, null).getPropertyValue("width") !== '44px'
    : false);
  }, 1, ['subpixel']);
});