earcons_background.js revision cedac228d2dd51db4b79ea1e72c7f249408ee061 
1// Copyright 2014 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5/**
6 * @fileoverview Earcons library that uses the HTML5 Audio element to play back
7 * auditory cues.
8 *
9 */
10
11
12goog.provide('cvox.EarconsBackground');
13
14goog.require('cvox.AbstractEarcons');
15
16
17/**
18 * @constructor
19 * @extends {cvox.AbstractEarcons}
20 */
21cvox.EarconsBackground = function() {
22  goog.base(this);
23
24  this.audioMap = new Object();
25  if (localStorage['earcons'] === 'false') {
26    this.enabled = false;
27  }
28};
29goog.inherits(cvox.EarconsBackground, cvox.AbstractEarcons);
30
31
32/**
33 * @return {string} The human-readable name of the earcon set.
34 */
35cvox.EarconsBackground.prototype.getName = function() {
36  return 'ChromeVox earcons';
37};
38
39
40/**
41 * @return {string} The base URL for loading earcons.
42 */
43cvox.EarconsBackground.prototype.getBaseUrl = function() {
44  return cvox.EarconsBackground.BASE_URL;
45};
46
47
48/**
49 * @override
50 */
51cvox.EarconsBackground.prototype.playEarcon = function(earcon) {
52  goog.base(this, 'playEarcon', earcon);
53  if (!this.enabled) {
54    return;
55  }
56  if (window['console']) {
57    window['console']['log']('Earcon ' + this.getEarconName(earcon));
58  }
59
60  this.currentAudio = this.audioMap[earcon];
61  if (!this.currentAudio) {
62    this.currentAudio = new Audio(this.getBaseUrl() +
63        this.getEarconFilename(earcon));
64    this.audioMap[earcon] = this.currentAudio;
65  }
66  try {
67    this.currentAudio.currentTime = 0;
68  } catch (e) {
69  }
70  if (this.currentAudio.paused) {
71    this.currentAudio.volume = 0.7;
72    this.currentAudio.play();
73  }
74};
75
76
77/**
78 * The base URL for  loading eracons.
79 * @type {string}
80 */
81cvox.EarconsBackground.BASE_URL = 'earcons/';
82