chrome/browser/resources/chromeos/chromevox/braille/nav_braille.js

   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 A simple container object for the brailling of a
   7  * navigation from one object to another.
   8  *
   9  */
  10
  11
  12 goog.provide('cvox.NavBraille');
  13
  14 goog.require('cvox.Spannable');
  15
  16 /**
  17  * A class capturing the braille for navigation from one object to
  18  * another.
  19  * @param {{text: (undefined|string|!cvox.Spannable),
  20  *          startIndex: (undefined|number),
  21  *          endIndex: (undefined|number)}} kwargs The arguments for braille.
  22  *  text The text of the object itself, including text from
  23  *     titles, labels, etc.
  24  *  startIndex The beginning of a selection within text.
  25  *  endIndex The end of a selection within text.
  26  * @constructor
  27  */
  28 cvox.NavBraille = function(kwargs) {
  29   /**
  30    * Text, annotated with DOM nodes.
  31    * @type {!cvox.Spannable}
  32    */
  33   this.text = (kwargs.text instanceof cvox.Spannable) ?
  34       kwargs.text : new cvox.Spannable(kwargs.text);
  35
  36   /**
  37    * Selection start index.
  38    * @type {number}
  39    */
  40   this.startIndex = goog.isDef(kwargs.startIndex) ? kwargs.startIndex : -1;
  41
  42   /**
  43    * Selection end index.
  44    * @type {number}
  45    */
  46   this.endIndex = goog.isDef(kwargs.endIndex) ?
  47       kwargs.endIndex : this.startIndex;
  48 };
  49
  50 /**
  51  * Convenience for creating simple braille output.
  52  * @param {string|!cvox.Spannable} text Text to represent in braille.
  53  * @return {!cvox.NavBraille} Braille output without a cursor.
  54  */
  55 cvox.NavBraille.fromText = function(text) {
  56   return new cvox.NavBraille({'text': text});
  57 };
  58
  59
  60 /**
  61  * Creates a NavBraille from its serialized json form as created
  62  * by toJson().
  63  * @param {!Object} json the serialized json object.
  64  * @return {!cvox.NavBraille}
  65  */
  66 cvox.NavBraille.fromJson = function(json) {
  67   if (typeof json.startIndex !== 'number' ||
  68       typeof json.endIndex !== 'number') {
  69     throw 'Invalid start or end index in serialized NavBraille: ' + json;
  70   }
  71   return new cvox.NavBraille({
  72     text: cvox.Spannable.fromJson(json.spannable),
  73     startIndex: json.startIndex,
  74     endIndex: json.endIndex
  75   });
  76 };
  77
  78
  79 /**
  80  * @return {boolean} true if this braille description is empty.
  81  */
  82 cvox.NavBraille.prototype.isEmpty = function() {
  83   return this.text.getLength() == 0;
  84 };
  85
  86
  87 /**
  88  * @return {string} A string representation of this object.
  89  */
  90 cvox.NavBraille.prototype.toString = function() {
  91   return 'NavBraille(text="' + this.text.toString() + '" ' +
  92          ' startIndex="' + this.startIndex + '" ' +
  93          ' endIndex="' + this.endIndex + '")';
  94 };
  95
  96
  97 /**
  98  * Returns a plain old data object with the same data.
  99  * Suitable for JSON encoding.
 100  *
 101  * @return {{spannable: Object,
 102  *           startIndex: number,
 103  *           endIndex: number}} JSON equivalent.
 104  */
 105 cvox.NavBraille.prototype.toJson = function() {
 106   return {
 107     spannable: this.text.toJson(),
 108     startIndex: this.startIndex,
 109     endIndex: this.endIndex
 110   };
 111 };