1 // Copyright 2013 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 // Braille display access private API. 6 namespace brailleDisplayPrivate { 7 // Braille display keyboard command. 8 enum KeyCommand { 9 line_up, 10 line_down, 11 pan_left, 12 pan_right, 13 top, 14 bottom, 15 routing, 16 secondary_routing, 17 dots, 18 standard_key 19 }; 20 21 // A keyboard event. This is not a standard keyboard event because 22 // braille display keyboards look significantly different from standard 23 // keyboards. 24 dictionary KeyEvent { 25 KeyCommand command; 26 // 0-based display position for commands that involve a routing key. 27 long? displayPosition; 28 // Braille dot keys that were pressed, stored in the low-order bits. 29 // Dot 1 is stored in bit 0, dot2 in bit 1, etc. 30 long? brailleDots; 31 // DOM keyboard event code. This is present when command is standard_key 32 // and the braille display event represents a non-alphanumeric key such 33 // as an arrow key or function key. 34 // The value is as defined by the |code| property in 35 // http://www.w3.org/TR/uievents/#keyboard-event-interface 36 DOMString? standardKeyCode; 37 // DOM keyboard event character value. This is present if the 38 // braille key event corresponds to a character. 39 DOMString? standardKeyChar; 40 // Whether the space key was pressed. 41 boolean? spaceKey; 42 // Whether the alt key was pressed. 43 boolean? altKey; 44 // Whether the shift key was pressed. 45 boolean? shiftKey; 46 // Whether the ctrl key was pressed. 47 boolean? ctrlKey; 48 }; 49 50 // The current braille display state. 51 dictionary DisplayState { 52 // Whether a braille display is currently available. 53 boolean available; 54 // Number of braille cells on the currently connected display. 55 long? textCellCount; 56 }; 57 58 callback DisplayStateCallback = void(DisplayState result); 59 60 interface Functions { 61 // Gets the current display state. 62 static void getDisplayState(DisplayStateCallback callback); 63 // Write the given dot patterns to the display. The buffer contains one 64 // byte for each braille cell on the display, starting from the leftmost 65 // cell. Each byte contains a bit pattern indicating which dots should be 66 // raised in the corresponding cell with the low-order bit representing 67 // dot 1 and so on until bit 7 which corresponds to dot 8. If the number 68 // of bytes in the buffer is not equal to the display size, the buffer 69 // will either be clipped or padded with blank cells on the right. 70 static void writeDots(ArrayBuffer cells); 71 }; 72 73 interface Events { 74 // Fired when a braille display is connected or disconnected. 75 static void onDisplayStateChanged(DisplayState state); 76 // Fired when an input event is received from the display. 77 static void onKeyEvent(KeyEvent event); 78 }; 79 }; 80