chrome/browser/resources/chromeos/chromevox/walkers/structural_line_walker.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 JavaScript class for walking lines.
   7  */
   8
   9
  10 goog.provide('cvox.StructuralLineWalker');
  11
  12 goog.require('cvox.AbstractSelectionWalker');
  13 goog.require('cvox.BrailleUtil');
  14 goog.require('cvox.TraverseContent');
  15
  16 /**
  17  * @constructor
  18  * @extends {cvox.AbstractSelectionWalker}
  19  */
  20 cvox.StructuralLineWalker = function() {
  21   goog.base(this);
  22   this.grain = cvox.TraverseContent.kLine;
  23 };
  24 goog.inherits(cvox.StructuralLineWalker, cvox.AbstractSelectionWalker);
  25
  26
  27 /**
  28  * @override
  29  */
  30 cvox.StructuralLineWalker.prototype.getGranularityMsg = function() {
  31   return cvox.ChromeVox.msgs.getMsg('structural_line');
  32 };
  33
  34
  35 /**
  36  * @override
  37  */
  38 cvox.StructuralLineWalker.prototype.getDescription = function(prevSel, sel) {
  39   var desc = goog.base(this, 'getDescription', prevSel, sel);
  40   desc[0].text = cvox.DomUtil.getPrefixText(
  41       sel.absStart().node, sel.absStart().index) + desc[0].text;
  42   return desc;
  43 };
  44
  45
  46 /**
  47  * @override
  48  */
  49 cvox.StructuralLineWalker.prototype.getBraille = function(prevSel, sel) {
  50   var braille = goog.base(this, 'getBraille', prevSel, sel);
  51
  52   var objNode = this.objWalker_.sync(sel).absStart().node;
  53   var node = sel.absStart().node;
  54   var prevNode = prevSel.absEnd().node;
  55
  56   // Show only the visible line in braille for DOM ranges. This overrides any
  57   // labels computed for the node.
  58   //
  59   // <textarea> needs to be treated specially. It may have TextNode children,
  60   // but these reflect the initial value of the node only, and are not updated
  61   // as content changes.
  62   var name = undefined;
  63   if (!sel.start.equals(sel.end) &&
  64       !cvox.DomPredicates.editTextPredicate([objNode])) {
  65     var prefix =
  66         cvox.DomUtil.getPrefixText(sel.absStart().node, sel.absStart().index);
  67     name = prefix + sel.getText();
  68   }
  69   var spannable =
  70       cvox.BrailleUtil.getTemplated(prevNode, objNode, {name: name});
  71   spannable.setSpan(objNode, 0, spannable.getLength());
  72   braille.text = spannable;
  73
  74   // Remove any selections.
  75   braille.startIndex = 0;
  76   braille.endIndex = 0;
  77   return braille;
  78 };