detect-web-font.js

   1
   2 /*!
   3  * isFontFaceSupported - v0.9 - 12/19/2009
   4  * http://paulirish.com/2009/font-face-feature-detection/
   5  *
   6  * Copyright (c) 2009 Paul Irish
   7  * MIT license
   8  */
   9
  10 module.exports = (function makeDetectWebFont() {
  11
  12     var fontret,
  13         fontfaceCheckDelay = 100;
  14
  15         // IE supports EOT and has had EOT support since IE 5.
  16         // This is a proprietary standard (ATOW) and thus this off-spec,
  17         // proprietary test for it is acceptable.
  18     if (!(!/*@cc_on@if(@_jscript_version>=5)!@end@*/0)) fontret = true;
  19
  20     else {
  21
  22     // Create variables for dedicated @font-face test
  23       var doc = document, docElement = doc.documentElement,
  24           st  = doc.createElement('style'),
  25           spn = doc.createElement('span'),
  26           wid, nwid, body = doc.body,
  27           callback, isCallbackCalled;
  28
  29       // The following is a font, only containing the - character. Thanks Ethan Dunham.
  30       st.textContent = "@font-face{font-family:testfont;src:url(data:font/opentype;base64,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)}";
  31       doc.getElementsByTagName('head')[0].appendChild(st);
  32
  33
  34       spn.setAttribute('style','font:99px _,serif;position:absolute;visibility:hidden');
  35
  36       if  (!body){
  37         body = docElement.appendChild(doc.createElement('fontface'));
  38       }
  39
  40       // the data-uri'd font only has the - character
  41       spn.innerHTML = '-------';
  42       spn.id        = 'fonttest';
  43
  44       body.appendChild(spn);
  45       wid = spn.offsetWidth;
  46
  47       spn.style.font = '99px testfont,_,serif';
  48
  49       // needed for the CSSFontFaceRule false positives (ff3, chrome, op9)
  50       fontret = wid !== spn.offsetWidth;
  51
  52       var delayedCheck = function(){
  53         if (isCallbackCalled) return;
  54         fontret = wid !== spn.offsetWidth;
  55         callback && (isCallbackCalled = true) && callback(fontret);
  56       }
  57
  58       addEventListener('load',delayedCheck,false);
  59       setTimeout(delayedCheck,fontfaceCheckDelay);
  60     }
  61
  62     function ret(){  return fontret || wid !== spn.offsetWidth; };
  63
  64     // allow for a callback
  65     return function (fn) {
  66       (isCallbackCalled || fontret) ? fn(fontret) : (callback = fn);
  67     };
  68
  69 })();