Addon that refreshes xterm upon webfont load

package.json

@@ -88,5 +88,7 @@
     "webpack": "gulp webpack",
     "watch": "gulp watch"
   },
-  "dependencies": {}
+  "dependencies": {
+    "fontfaceobserver": "*"
+  }
 }

src/addons/webfont/package.json

@@ -0,0 +1,5 @@
+{
+  "name": "xterm.webfont",
+  "main": "webfont.js",
+  "private": true
+}

src/addons/webfont/tsconfig.json

@@ -0,0 +1,11 @@
+{
+  "compilerOptions": {
+    "module": "commonjs",
+    "target": "es5",
+    "rootDir": ".",
+    "outDir": "../../../lib/addons/webfont/",
+    "sourceMap": true,
+    "removeComments": true,
+    "declaration": true
+  }
+}

src/addons/webfont/webfont.ts

@@ -0,0 +1,26 @@
+/// <reference path="../../../typings/xterm.d.ts"/>
+
+import { Terminal } from 'xterm';
+const FontFaceObserver = require('fontfaceobserver')
+
+const loadedFonts = {}
+
+export function apply(terminalConstructor: typeof Terminal): void {
+  const oldSetup = (<any>terminalConstructor.prototype)._setup;
+
+  (<any>terminalConstructor.prototype)._setup = function (): void {
+    const originalFont = this.options.fontFamily;
+    if (loadedFonts[originalFont]) return oldSetup.call(this);
+    delete this.options.fontFamily;
+    oldSetup.call(this);
+
+    const regular = new FontFaceObserver(originalFont).load();
+    const bold = new FontFaceObserver(originalFont, { weight: 'bold' }).load();
+
+    regular.constructor.all([regular, bold]).then(() => {
+      loadedFonts[originalFont] = true;
+      this.setOption('fontFamily', originalFont);
+      this.refresh(0, this.rows - 1);
+    });
+  };
+}