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      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 Braille command definitions.
      7  * These types are adapted from Chrome's private braille API.
      8  * They can be found in the Chrome source repo at:
      9  * src/chrome/common/extensions/api/braille_display_private.idl
     10  * We define them here since they don't actually exist as bindings under
     11  * chrome.brailleDisplayPrivate.*.
     12  */
     13 
     14 goog.provide('cvox.BrailleDisplayState');
     15 goog.provide('cvox.BrailleKeyCommand');
     16 goog.provide('cvox.BrailleKeyEvent');
     17 
     18 goog.require('cvox.ChromeVox');
     19 
     20 
     21 /**
     22  * The set of commands sent from a braille display.
     23  * @enum {string}
     24  */
     25 cvox.BrailleKeyCommand = {
     26   PAN_LEFT: 'pan_left',
     27   PAN_RIGHT: 'pan_right',
     28   LINE_UP: 'line_up',
     29   LINE_DOWN: 'line_down',
     30   TOP: 'top',
     31   BOTTOM: 'bottom',
     32   ROUTING: 'routing',
     33   SECONDARY_ROUTING: 'secondary_routing',
     34   DOTS: 'dots',
     35   STANDARD_KEY: 'standard_key'
     36 };
     37 
     38 
     39 /**
     40  * Represents a key event from a braille display.
     41  *
     42  * @typedef {{command: cvox.BrailleKeyCommand,
     43  *            displayPosition: (undefined|number),
     44  *            brailleDots: (undefined|number),
     45  *            standardKeyCode: (undefined|string),
     46  *            standardKeyChar: (undefined|string),
     47  *            altKey: (undefined|boolean),
     48  *            ctrlKey: (undefined|boolean),
     49  *            shiftKey: (undefined|boolean)
     50  *          }}
     51  *  command The name of the command.
     52  *  displayPosition The 0-based position relative to the start of the currently
     53  *                  displayed text.  Used for commands that involve routing
     54  *                  keys or similar.  The position is given in characters,
     55  *                  not braille cells.
     56  *  brailleDots Dots that were pressed for braille input commands.  Bit mask
     57  *              where bit 0 represents dot 1 etc.
     58  * standardKeyCode DOM level 4 key code.
     59  * standardKeyChar DOM key event character.
     60  * altKey Whether the alt key was pressed.
     61  * ctrlKey Whether the control key was pressed.
     62  * shiftKey Whether the shift key was pressed.
     63  */
     64 cvox.BrailleKeyEvent = {};
     65 
     66 
     67 /**
     68  * Returns the numeric key code for a DOM level 4 key code string.
     69  * NOTE: Only the key codes produced by the brailleDisplayPrivate API are
     70  * supported.
     71  * @param {string} code DOM level 4 key code.
     72  * @return {number|undefined} The numeric key code, or {@code undefined}
     73  *     if unknown.
     74  */
     75 cvox.BrailleKeyEvent.keyCodeToLegacyCode = function(code) {
     76   return cvox.BrailleKeyEvent.legacyKeyCodeMap_[code];
     77 };
     78 
     79 
     80 /**
     81  * Returns a char value appropriate for a synthezised key event for a given
     82  * key code.
     83  * @param {string} keyCode The DOM level 4 key code.
     84  * @return {number} Integral character code.
     85  */
     86 cvox.BrailleKeyEvent.keyCodeToCharValue = function(keyCode) {
     87   /** @const */
     88   var SPECIAL_CODES = {
     89     'Backspace': 0x08,
     90     'Tab': 0x09,
     91     'Enter': 0x0A
     92   };
     93   // Note, the Chrome virtual keyboard falls back on the first character of the
     94   // key code if the key is not one of the above.  Do the same here.
     95   return SPECIAL_CODES[keyCode] || keyCode.charCodeAt(0);
     96 };
     97 
     98 
     99 /**
    100  * Map from DOM level 4 key codes to legacy numeric key codes.
    101  * @private {Object.<string, number>}
    102  */
    103 cvox.BrailleKeyEvent.legacyKeyCodeMap_ = {
    104   'Backspace': 8,
    105   'Tab': 9,
    106   'Enter': 13,
    107   'Escape': 27,
    108   'Home': 36,
    109   'ArrowLeft': 37,
    110   'ArrowUp': 38,
    111   'ArrowRight': 39,
    112   'ArrowDown': 40,
    113   'PageUp': 33,
    114   'PageDown': 34,
    115   'End': 35,
    116   'Insert': 45,
    117   'Delete': 46
    118 };
    119 
    120 // Add the F1 to F12 keys.
    121 (function() {
    122   for (var i = 0; i < 12; ++i) {
    123     cvox.BrailleKeyEvent.legacyKeyCodeMap_['F' + (i + 1)] = 112 + i;
    124   }
    125 })();
    126 
    127 
    128 /**
    129  * The state of a braille display as represented in the
    130  * chrome.brailleDisplayPrivate API.
    131  * @typedef {{available: boolean, textCellCount: (number|undefined)}}
    132  */
    133 cvox.BrailleDisplayState;
    134