feat : add gen_metrics.js to generate font metrics

Author: Olivier Bonnaure

gen_metrics.js

@@ -0,0 +1,10 @@
+const opentype = require('opentype.js');
+
+opentype.load(process.argv[2], function (err, font) {
+  var codes = {}
+
+  for(let i = 32; i < 257; i++) {
+    codes[i] = font.getAdvanceWidth(String.fromCharCode(i), 1000)
+  }
+  console.log(JSON.stringify(codes))
+})