Read ligature from a font

Is it possible to read the “ligatures” from a font?

What I mean is, get a dictionary (an array) where the key is the substituion and the value is the Glyph object (or just the unicode integer value), something like:

var font = ... ; // a Font object
var ligatures = font.getLigatures();  // an array where key is the ligature, value is the Glyph(or just the unicode integer will do it too)
foreach(var l in ligatures) {
    console.log(l, ligatures[l]); // 
}

For example, Google’s Material Icons font has the “face” ligature, see: https://google.github.io/material-design-icons/#using-the-icons-in-html

[vinuel]

To get a list of ligatures would really be helpful!

Recently a FontDrop! user sent me a script that he used to get ligatures. He wrote:

Below is the JavaScript I used to grab the ligatures. It’s missing the first character for each ligature, but that was good enough for me.

Here is the code

(function(){
  var glyphIndexMap = {"0":1,"1":3,"32":4,"95":5,"97":6,"98":7,"99":8,"100":9,"101":10,"102":11,"103":12,"104":13,"105":14,"107":15,"108":16,"109":17,"110":18,"111":19,"112":20,"114":21,"115":22,"116":23,"117":24,"118":25,"119":26,"121":27,"9724":28,"57549":29,"57569":30,"57573":31,"58131":32,"58133":33,"58134":34,"58821":35,"58829":36,"58834":37,"58840":38,"59389":39,"59448":40,"59449":41,"59450":42,"59517":43,"59518":44,"59530":45,"59572":46,"59574":47,"59595":48,"59596":49,"59611":50,"59612":51,"59648":52,"59649":53,"59650":54,"59651":55,"59652":56,"59653":57,"59654":58,"59655":59,"59656":60,"59657":61,"59658":62,"59659":63};
  var reverseGlyphIndexMap = {};
  Object.keys(glyphIndexMap).forEach(function(key){
    var value = glyphIndexMap[key];
    reverseGlyphIndexMap[value] = key;
    });
  var lookups = {"lookupType":4,"lookupFlag":0,"subtables":[{"substFormat":1,"coverage":{"format":2,"ranges":[{"start":6,"end":8,"index":0},{"start":10,"end":14,"index":3},{"start":17,"end":18,"index":8},{"start":20,"end":24,"index":10},{"start":26,"end":27,"index":15}]},"ligatureSets":[[{"ligGlyph":38,"components":[21,21,19,26,5,24,20,26,6,21,9]},{"ligGlyph":35,"components":[18,12,16,10,5,9,19,26,18]}],[{"ligGlyph":48,"components":[6,22,15,10,23]},{"ligGlyph":57,"components":[16,19,12]}],[{"ligGlyph":33,"components":[13,10,25,21,19,18,5,21,14,12,13,23]},{"ligGlyph":32,"components":[13,10,25,21,19,18,5,9,19,26,18]},{"ligGlyph":34,"components":[13,10,25,21,19,18,5,24,20]},{"ligGlyph":36,"components":[16,19,22,10]},{"ligGlyph":49,"components":[6,21,23]}],[{"ligGlyph":30,"components":[18,25,10,16,19,20,10]}],[{"ligGlyph":61,"components":[6,8,10,7,19,19,15]},{"ligGlyph":54,"components":[16,14,8,15,21]}],[{"ligGlyph":53,"components":[19,19,12,16,10]}],[{"ligGlyph":44,"components":[10,6,21,23,5,7,19,21,9,10,21]},{"ligGlyph":43,"components":[10,6,21,23]},{"ligGlyph":45,"components":[19,17,10]}],[{"ligGlyph":59,"components":[18,22,23,6,12,21,6,17]}],[{"ligGlyph":46,"components":[6,21,15,10,21]},{"ligGlyph":37,"components":[10,18,24]}],[{"ligGlyph":52,"components":[10,26,22]}],[{"ligGlyph":58,"components":[14,18,23,10,21,10,22,23]},{"ligGlyph":29,"components":[13,19,18,10]}],[{"ligGlyph":31,"components":[22,22]}],[{"ligGlyph":42,"components":[23,6,21,5,7,19,21,9,10,21]},{"ligGlyph":41,"components":[23,6,21,5,13,6,16,11]},{"ligGlyph":47,"components":[10,6,21,8,13]},{"ligGlyph":40,"components":[23,6,21]}],[{"ligGlyph":50,"components":[13,24,17,7,5,9,19,26,18]},{"ligGlyph":51,"components":[13,24,17,7,5,24,20]},{"ligGlyph":63,"components":[13,10,15,18,19,26]},{"ligGlyph":60,"components":[26,14,23,23,10,21]}],[{"ligGlyph":39,"components":[22,10,21]}],[{"ligGlyph":62,"components":[10,9,9,14,18,12,26,14,21,10]}],[{"ligGlyph":55,"components":[19,24,23,24,7,10]},{"ligGlyph":56,"components":[10,16,20]}]]}]};
  var ligatureSets = lookups.subtables[0].ligatureSets;
  ligatureSets.forEach(function(set){
    set.forEach(function(ligature){
     ligature.components = ligature.components.map(function(component){
       component = reverseGlyphIndexMap[component];
       component = parseInt(component);
       return String.fromCharCode(component);
      });
      console.log(ligature.components.join(''));
   });
  });
})();

I’m not a javascript developer, but maybe it is a starting point …

[petermikitsh]

I made an NPM module for getting an array of ligature names from a font. It’s published to npm as ligatures. https://github.com/petermikitsh/ligatures