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

chrome/browser/resources/access_chromevox/audio/common/abstract_tts.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 Base class for Text-To-Speech-Engines.
+ */
+
+goog.provide('cvox.AbstractTts');
+
+goog.require('cvox.AbstractLogger');
+
+/**
+ * Creates a new instance.
+ * @constructor
+ * @extends {cvox.AbstractLogger}
+ */
+cvox.AbstractTts = function() {
+  //Inherit AbstractLogger
+  cvox.AbstractLogger.call(this);
+  this.ttsProperties = new Object();
+};
+goog.inherits(cvox.AbstractTts, cvox.AbstractLogger);
+
+/**
+ * Default TTS properties for this TTS engine.
+ * @type {Object}
+ * @protected
+ */
+cvox.AbstractTts.prototype.ttsProperties;
+
+/**
+ * Override the super class method to configure logging.
+ * @return {boolean} If logging is enabled.
+ */
+cvox.AbstractTts.prototype.logEnabled = function() {
+  return cvox.AbstractTts.DEBUG;
+};
+
+/**
+ * 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: cvox.AbstractTts.QUEUE_MODE_FLUSH
+ *        for flush, cvox.AbstractTts.QUEUE_MODE_QUEUE for adding to queue.
+ * @param {Object=} properties Speech properties to use for this utterance.
+ */
+cvox.AbstractTts.prototype.speak = function(textString, queueMode,
+    properties) {
+  if (this.logEnabled()) {
+    this.log('[' + this.getName() + '] speak(' + textString + ', ' + queueMode +
+        (properties ? ', ' + properties.toString() : '') + ')');
+  }
+};
+
+/**
+ * Returns true if the TTS is currently speaking.
+ * @return {boolean} True if the TTS is speaking.
+ */
+cvox.AbstractTts.prototype.isSpeaking = function() {
+  if (this.logEnabled()) {
+    this.log('[' + this.getName() + '] isSpeaking()');
+  }
+  return false;
+};
+
+/**
+ * Stops speech.
+ */
+cvox.AbstractTts.prototype.stop = function() {
+  if (this.logEnabled()) {
+    this.log('[' + this.getName() + '] stop()');
+  }
+};
+
+/**
+ * Retrieves the default TTS properties for this TTS engine.
+ * @return {Object} Default TTS properties.
+ */
+cvox.AbstractTts.prototype.getDefaultTtsProperties = function() {
+  return this.ttsProperties;
+};
+
+/**
+ * Sets the default TTS properties for this TTS engine.
+ * @param {Object} ttsProperties Default TTS properties.
+ */
+cvox.AbstractTts.prototype.setDefaultTtsProperties = function(ttsProperties) {
+  this.ttsProperties = ttsProperties;
+};
+
+/**
+ * Increases a TTS speech property.
+ * @param {string} property_name The name of the property to increase.
+ */
+cvox.AbstractTts.prototype.increaseProperty = function(property_name) {
+  if (property_name == cvox.AbstractTts.TTS_PROPERTY_RATE) {
+    this.ttsProperties.rate = this.increasePropertyValue(
+        this.ttsProperties.rate);
+    this.speak(cvox.AbstractTts.str.increaseRate, 0, this.ttsProperties);
+  } else if (property_name == cvox.AbstractTts.TTS_PROPERTY_PITCH) {
+    this.ttsProperties.pitch = this.increasePropertyValue(
+        this.ttsProperties.pitch);
+    this.speak(cvox.AbstractTts.str.increasePitch, 0, this.ttsProperties);
+  } else if (property_name == cvox.AbstractTts.TTS_PROPERTY_VOLUME) {
+    this.ttsProperties.volume = this.increasePropertyValue(
+        this.ttsProperties.volume);
+    this.speak(cvox.AbstractTts.str.increaseVolume, 0, this.ttsProperties);
+  }
+};
+
+/**
+ * Decreases a TTS speech property.
+ * @param {string} property_name The name of the property to decrease.
+ */
+cvox.AbstractTts.prototype.decreaseProperty = function(property_name) {
+  if (property_name == cvox.AbstractTts.TTS_PROPERTY_RATE) {
+    this.ttsProperties.rate = this.decreasePropertyValue(
+        this.ttsProperties.rate);
+    this.speak(cvox.AbstractTts.str.decreaseRate, 0, this.ttsProperties);
+  } else if (property_name == cvox.AbstractTts.TTS_PROPERTY_PITCH) {
+    this.ttsProperties.pitch = this.decreasePropertyValue(
+        this.ttsProperties.pitch);
+    this.speak(cvox.AbstractTts.str.decreasePitch, 0, this.ttsProperties);
+  } else if (property_name == cvox.AbstractTts.TTS_PROPERTY_VOLUME) {
+    this.ttsProperties.volume = this.decreasePropertyValue(
+        this.ttsProperties.volume);
+    this.speak(cvox.AbstractTts.str.decreaseVolume, 0, this.ttsProperties);
+  }
+};
+
+/**
+ * Merges the given properties with the default ones.
+ * @param {Object=} properties The properties to merge with the default.
+ * @return {Object} The merged properties.
+ */
+cvox.AbstractTts.prototype.mergeProperties = function(properties) {
+  if (!properties) {
+    return this.ttsProperties;
+  }
+  // Merge the default properties with the properties from this message,
+  // so that the defaults are always passed along but the message
+  // always overrides.
+  var mergedProperties = new Object();
+  for (var p in this.ttsProperties) {
+    mergedProperties[p] = this.ttsProperties[p];
+  }
+  for (var p in properties) {
+    mergedProperties[p] = properties[p];
+  }
+  return mergedProperties;
+};
+
+/**
+ * Decrease by 0.1 the value of a TTS property that's normally in the range
+ * 0.0 - 1.0, and make sure it doesn't end up smaller than 0.0. Return the
+ * new value.
+ * @param {number} current_value The current value of the property.
+ * @return {number} The new value.
+ */
+cvox.AbstractTts.prototype.decreasePropertyValue = function(current_value) {
+  return Math.max(0.0, current_value - 0.1);
+};
+
+/**
+ * Increase by 0.1 the value of a TTS property that's normally in the range
+ * 0.0 - 1.0, and make sure it doesn't end up larger than 1.0. Return the
+ * new value.
+ * @param {number} current_value The current value of the property.
+ * @return {number} The new value.
+ */
+cvox.AbstractTts.prototype.increasePropertyValue = function(current_value) {
+  return Math.min(1.0, current_value + 0.1);
+};
+
+/**
+ * TTS rate property.
+ * @type {string}
+ */
+cvox.AbstractTts.TTS_PROPERTY_RATE = 'Rate';
+
+/**
+ * TTS pitch property.
+ * @type {string}
+ */
+cvox.AbstractTts.TTS_PROPERTY_PITCH = 'Pitch';
+
+/**
+ * TTS volume property.
+ * @type {string}
+ */
+cvox.AbstractTts.TTS_PROPERTY_VOLUME = 'Volume';
+
+/**
+ * Flag indicating if the TTS is being debugged.
+ * @type {boolean}
+ */
+cvox.AbstractTts.DEBUG = true;
+
+/**
+ * Speech queue mode that interrupts the current utterance.
+ * @type {number}
+ */
+cvox.AbstractTts.QUEUE_MODE_FLUSH = 0;
+
+/**
+ * Speech queue mode that does not interrupt the current utterance.
+ * @type {number}
+ */
+cvox.AbstractTts.QUEUE_MODE_QUEUE = 1;
+
+/**
+* String constants.
+* @type {Object}
+*/
+cvox.AbstractTts.str = {
+  'increaseRate': 'increasing rate',
+  'increasePitch': 'increasing pitch',
+  'increaseVolume': 'increasing volume',
+  'decreaseRate': 'decreasing rate',
+  'decreasePitch': 'decreasing pitch',
+  'decreaseVolume': 'decreasing volume'
+};
+