Source Code for Module brailleDisplayDrivers.brltty

  1  #brailleDisplayDrivers/brltty.py 
  2  #A part of NonVisual Desktop Access (NVDA) 
  3  #This file is covered by the GNU General Public License. 
  4  #See the file COPYING for more details. 
  5  #Copyright (C) 2008-2010 James Teh <jamie@jantrid.net> 
  6   
  7  import time 
  8  import wx 
  9  import braille 
 10  from logHandler import log 
 11  import inputCore 
 12  try: 
 13          import brlapi 
 14          BRLAPI_CMD_KEYS = dict((code, name[8:].lower()) 
 15                  for name, code in brlapi.__dict__.iteritems() if name.startswith("KEY_CMD_")) 
 16  except ImportError: 
 17          pass 
 18   
 19  KEY_CHECK_INTERVAL = 50 
 20   
 21 -class BrailleDisplayDriver(braille.BrailleDisplayDriver): 
 22          """brltty braille display driver. 
 23          """ 
 24          name = "brltty" 
 25          description = "brltty" 
 26   
 27          @classmethod 
 28 -        def check(cls): 
 29                  try: 
 30                          brlapi 
 31                          return True 
 32                  except NameError: 
 33                          pass 
 34                  return False 
 35   
 36 -        def __init__(self): 
 37                  super(BrailleDisplayDriver, self).__init__() 
 38                  self._con = brlapi.Connection() 
 39                  self._con.enterTtyModeWithPath() 
 40                  self._keyCheckTimer = wx.PyTimer(self._handleKeyPresses) 
 41                  self._keyCheckTimer.Start(KEY_CHECK_INTERVAL) 
 42                  # BRLTTY simulates key presses for braille typing keys, so let BRLTTY handle them. 
 43                  # NVDA may eventually implement this itself, but there's no reason to deny BRLTTY users this functionality in the meantime. 
 44                  self._con.ignoreKeys(brlapi.rangeType_type, (long(brlapi.KEY_TYPE_SYM),)) 
 45   
 46 -        def terminate(self): 
 47                  super(BrailleDisplayDriver, self).terminate() 
 48                  # Exceptions might be raised if initialisation failed. Just ignore them. 
 49                  try: 
 50                          self._keyCheckTimer.Stop() 
 51                          self._keyCheckTimer = None 
 52                  except: 
 53                          pass 
 54                  try: 
 55                          # Give BRLTTY a chance to write the last piece of data to the display. 
 56                          time.sleep(0.05) 
 57                          self._con.leaveTtyMode() 
 58                  except: 
 59                          pass 
 60   
 61 -        def _get_numCells(self): 
 62                  return self._con.displaySize[0] 
 63   
 64 -        def display(self, cells): 
 65                  cells = "".join(chr(cell) for cell in cells) 
 66                  # HACK: Temporarily work around a bug which causes brltty to freeze if data is written while there are key presses waiting. 
 67                  # Simply consume and act upon any waiting key presses. 
 68                  self._handleKeyPresses() 
 69                  self._con.writeDots(cells) 
 70   
 71 -        def _handleKeyPresses(self): 
 72                  while True: 
 73                          try: 
 74                                  key = self._con.readKey(False) 
 75                          except: 
 76                                  log.error("Error reading key press from brlapi", exc_info=True) 
 77                                  return 
 78                          if not key: 
 79                                  break 
 80                          key = self._con.expandKeyCode(key) 
 81                          self._onKeyPress(key) 
 82   
 83 -        def _onKeyPress(self, key): 
 84                  keyType = key["type"] 
 85                  command = key["command"] 
 86                  argument = key["argument"] 
 87                  if keyType == brlapi.KEY_TYPE_CMD: 
 88                          try: 
 89                                  inputCore.manager.executeGesture(InputGesture(command, argument)) 
 90                          except inputCore.NoInputGestureAction: 
 91                                  pass 
 92   
 93          gestureMap = inputCore.GlobalGestureMap({ 
 94                  "globalCommands.GlobalCommands": { 
 95                          "braille_scrollBack": ("br(brltty):fwinlt",), 
 96                          "braille_scrollForward": ("br(brltty):fwinrt",), 
 97                          "braille_previousLine": ("br(brltty):lnup",), 
 98                          "braille_nextLine": ("br(brltty):lndn",), 
 99                          "braille_routeTo": ("br(brltty):route",), 
100                  } 
101          }) 
102   
103 -class InputGesture(braille.BrailleDisplayGesture): 
104   
105          source = BrailleDisplayDriver.name 
106   
107 -        def __init__(self, command, argument): 
108                  super(InputGesture, self).__init__() 
109                  self.id = BRLAPI_CMD_KEYS[command] 
110                  if command == brlapi.KEY_CMD_ROUTE: 
111                          self.routingIndex = argument 
112