Web Component Virtual Keyboard

ui/keyboard/resources/voice_input.js

+// Copyright (c) 2013 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.
+
+function VoiceInput(keyboard) {
+  this.finaResult_ = null;
+  this.recognizing_ = false;
+  this.keyboard_ = keyboard;
+  this.recognition_ = new webkitSpeechRecognition();
+  this.recognition_.onstart = this.onStartHandler.bind(this);
+  this.recognition_.onresult = this.onResultHandler.bind(this);
+  this.recognition_.onerror = this.onErrorHandler.bind(this);
+  this.recognition_.onend = this.onEndHandler.bind(this);
+};
+
+VoiceInput.prototype = {
+  /**
+   * Event handler for mouse/touch down events.
+   */
+  onDown: function() {
+    if (this.recognizing_) {
+      this.recognition_.stop();
+      return;
+    }
+    this.recognition_.start();
+  },
+
+  /**
+   * Speech recognition started. Change mic key's icon.
+   */
+  onStartHandler: function() {
+    this.recognizing_ = true;
+    this.finalResult_ = '';
+    if (!this.keyboard_.classList.contains('audio'))
+      this.keyboard_.classList.add('audio');
+  },
+
+  /**
+   * Speech recognizer returns a result.
+   * @param{Event} e The SpeechRecognition event that is raised each time
+   *     there
+   *     are any changes to interim or final results.
+   */
+  onResultHandler: function(e) {
+    for (var i = e.resultIndex; i < e.results.length; i++) {
+      if (e.results[i].isFinal)
+        this.finalResult_ = e.results[i][0].transcript;
+    }
+    for (var i = 0; i < this.finalResult_.length; i++) {
+      var keyEvent = {
+        keyIdentifier: this.finalResult_.charAt(i)
+      };
+      sendKeyEvent(keyEvent);
+    }
+  },
+
+  /**
+   * Speech recognizer returns an error.
+   * @param{Event} e The SpeechRecognitionError event that is raised each time
+   *     there is an error.
+   */
+  onErrorHandler: function(e) {
+    console.error('error code = ' + e.error);
+  },
+
+  /**
+   * Speech recognition ended. Reset mic key's icon.
+   */
+  onEndHandler: function() {
+    if (this.keyboard_.classList.contains('audio'))
+      this.keyboard_.classList.remove('audio');
+    this.recognizing_ = false;
+  }
+};