Adding ChromeVox as a component extensions (enabled only for ChromeOS, for no...

chrome/browser/resources/access_chromevox/audio/background/gooss_engine.js

+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+/**
+ * @fileoverview Text-To-Speech engine powered by GooSS. This engine relies on
+ * HTML5.
+ *
+ * Note: There are currently still a few problems with long utterances and the
+ * way GooSS generates MP3s.
+ */
+
+goog.provide('cvox.ChromeVoxGoossEngine');
+
+goog.require('cvox.AbstractTts');
+
+/**
+ * @constructor
+ * @extends {cvox.AbstractTts}
+ */
+cvox.ChromeVoxGoossEngine = function() {
+  //Inherit AbstractTts
+  cvox.AbstractTts.call(this);
+
+  this.speechServerUrl = 'http://www.google.com/speech-api/' +
+      'v1/synthesize?lang=en-us&text=';
+  this.audioElem = document.createElement('audio');
+};
+goog.inherits(cvox.ChromeVoxGoossEngine, cvox.AbstractTts);
+
+/**
+ * @return {string} The human-readable name of the speech engine.
+ */
+cvox.ChromeVoxGoossEngine.prototype.getName = function() {
+  return 'Google Network Speech';
+};
+
+/**
+ * Speaks the given string using the specified queueMode and properties.
+ * @param {string} textString The string of text to be spoken.
+ * @param {number=} queueMode The queue mode: AbstractTts.QUEUE_MODE_FLUSH
+ *        for flush, AbstractTts.QUEUE_MODE_QUEUE for adding to queue.
+ * @param {Object=} properties Speech properties to use for this utterance.
+ */
+cvox.ChromeVoxGoossEngine.prototype.speak = function(textString, queueMode,
+    properties) {
+  cvox.ChromeVoxGoossEngine.superClass_.speak.call(this, textString,
+    queueMode, properties);
+  // TODO: Implement speech queue so that queued speech is possible
+  this.audioElem.pause();
+  this.audioElem.src = this.speechServerUrl + escape(textString);
+  this.audioElem.autoplay = true;
+  this.isSpeaking_ = true;
+  this.audioElem.addEventListener('ended', function(evt) {
+    this.isSpeaking_ = false;
+  }, true);
+};
+
+/**
+ * Returns true if the TTS is currently speaking.
+ * @return {boolean} True if the TTS is speaking.
+ */
+cvox.ChromeVoxGoossEngine.prototype.isSpeaking = function() {
+  cvox.ChromeVoxGoossEngine.superClass_.isSpeaking.call(this);
+  return this.isSpeaking_;
+};
+
+/**
+ * Stops speech.
+ */
+cvox.ChromeVoxGoossEngine.prototype.stop = function() {
+  cvox.ChromeVoxGoossEngine.superClass_.stop.call(this);
+  this.audioElem.pause();
+};