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// Copyright 2014 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.
goog.provide('cvox.ChromeVoxHTMLMediaWidget');
/**
* @fileoverview Gives the user spoken feedback as they interact with the HTML5
* media widgets (<video> and <audio>) + makes the widget keyboard accessible.
*
*/
/**
* A class containing the information needed to speak
* a media element to the user.
*
* @constructor
* @param {Element} mediaElem The media widget element.
* @param {cvox.TtsInterface} tts The TTS object from ChromeVox.
*/
cvox.ChromeVoxHTMLMediaWidget = function(mediaElem, tts){
var self = this;
this.mediaElem_ = mediaElem;
this.mediaTts_ = tts;
this.keyListener_ = function(evt) {
self.eventHandler_(evt);
}
this.blurListener_ = function(evt) {
self.shutdown();
}
this.mediaElem_.addEventListener('keydown', this.keyListener_, false);
this.mediaElem_.addEventListener('keyup', this.keyListener_, false);
this.mediaElem_.addEventListener('blur', this.blurListener_, false);
};
/**
* Removes the key listeners for the media widget.
*/
cvox.ChromeVoxHTMLMediaWidget.prototype.shutdown = function() {
this.mediaElem_.removeEventListener('blur', this.blurListener_, false);
this.mediaElem_.removeEventListener('keydown', this.keyListener_, false);
this.mediaElem_.removeEventListener('keyup', this.keyListener_, false);
};
cvox.ChromeVoxHTMLMediaWidget.prototype.jumpToTime_ = function(targetTime) {
if (targetTime < 0) {
targetTime = 0;
}
if (targetTime > this.mediaElem_.duration) {
targetTime = this.mediaElem_.duration;
}
this.mediaElem_.currentTime = targetTime;
};
cvox.ChromeVoxHTMLMediaWidget.prototype.setVolume_ = function(targetVolume) {
if (targetVolume < 0) {
targetVolume = 0;
}
if (targetVolume > 1.0) {
targetVolume = 1.0;
}
this.mediaElem_.volume = targetVolume;
};
/**
* Adds basic keyboard handlers to the media widget.
*/
cvox.ChromeVoxHTMLMediaWidget.prototype.eventHandler_ = function(evt) {
if (evt.type == 'keydown') {
// Space/Enter for play/pause toggle.
if ((evt.keyCode == 13) || (evt.keyCode == 32)) {
if (this.mediaElem_.paused){
this.mediaElem_.play();
} else {
this.mediaElem_.pause();
}
} else if (evt.keyCode == 39) { // Right - FF
this.jumpToTime_(
this.mediaElem_.currentTime + (this.mediaElem_.duration/10));
} else if (evt.keyCode == 37) { // Left - REW
this.jumpToTime_(
this.mediaElem_.currentTime - (this.mediaElem_.duration/10));
} else if (evt.keyCode == 38) { // Up - Vol. Up
this.setVolume_(this.mediaElem_.volume + .1);
} else if (evt.keyCode == 40) { // Down - Vol. Down
this.setVolume_(this.mediaElem_.volume - .1);
}
}
};
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