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# Orca
#
# Copyright 2005-2006 Sun Microsystems Inc.
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Library General Public
# License as published by the Free Software Foundation; either
# version 2 of the License, or (at your option) any later version.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# Library General Public License for more details.
#
# You should have received a copy of the GNU Library General Public
# License along with this library; if not, write to the
# Free Software Foundation, Inc., 59 Temple Place - Suite 330,
# Boston, MA 02111-1307, USA.
"""A very experimental approach to the refreshable Braille display. This
module treats each line of the display as a sequential set of regions, where
each region can potentially backed by an Accessible object. Depending upon
the Accessible object, the cursor routing keys can be used to perform
operations on the Accessible object, such as invoking default actions or
moving the text caret.
"""
__id__ = "$Id: braille.py,v 1.59 2006/07/28 11:33:32 wwalker Exp $"
__version__ = "$Revision: 1.59 $"
__date__ = "$Date: 2006/07/28 11:33:32 $"
__copyright__ = "Copyright (c) 2005-2006 Sun Microsystems Inc."
__license__ = "LGPL"
import signal
import threading
import atspi
import brl
try:
# This can fail due to gtk not being available. We want to
# be able to recover from that if possible. The main driver
# for this is to allow "orca --text-setup" to work even if
# the desktop is not running.
#
import brlmon
except:
pass
import debug
import eventsynthesizer
import settings
import util
from orca_i18n import _ # for gettext support
from rolenames import getShortBrailleForRoleName # localized role names
from rolenames import getLongBrailleForRoleName # localized role names
# If True, this module has been initialized.
#
_initialized = False
# The braille monitor
#
monitor = None
# Each of these maps to BrlAPI's brldefs.h file.
#
CMD_NOOP = 0x00
CMD_LNUP = 0x01
CMD_LNDN = 0x02
CMD_WINUP = 0x03
CMD_WINDN = 0x04
CMD_PRDIFLN = 0x05
CMD_NXDIFLN = 0x06
CMD_ATTRUP = 0x07
CMD_ATTRDN = 0x08
CMD_TOP = 0x09
CMD_BOT = 0x0a
CMD_TOP_LEFT = 0x0b
CMD_BOT_LEFT = 0x0c
CMD_PRPGRPH = 0x0d
CMD_NXPGRPH = 0x0e
CMD_PRPROMPT = 0x0f
CMD_NXPROMPT = 0x10
CMD_PRSEARCH = 0x11
CMD_NXSEARCH = 0x12
CMD_CHRLT = 0x13
CMD_CHRRT = 0x14
CMD_HWINLT = 0x15
CMD_HWINRT = 0x16
CMD_FWINLT = 0x17
CMD_FWINRT = 0x18
CMD_FWINLTSKIP = 0x19
CMD_FWINRTSKIP = 0x1a
CMD_LNBEG = 0x1b
CMD_LNEND = 0x1c
CMD_HOME = 0x1d
CMD_BACK = 0x1e
CMD_FREEZE = 0x1f
CMD_DISPMD = 0x20
CMD_SIXDOTS = 0x21
CMD_SLIDEWIN = 0x22
CMD_SKPIDLNS = 0x23
CMD_SKPBLNKWINS = 0x24
CMD_CSRVIS = 0x25
CMD_CSRHIDE = 0x26
CMD_CSRTRK = 0x27
CMD_CSRSIZE = 0x28
CMD_CSRBLINK = 0x29
CMD_ATTRVIS = 0x2a
CMD_ATTRBLINK = 0x2b
CMD_CAPBLINK = 0x2c
CMD_TUNES = 0x2d
CMD_HELP = 0x2e
CMD_INFO = 0x2f
CMD_LEARN = 0x30
CMD_PREFMENU = 0x31
CMD_PREFSAVE = 0x32
CMD_PREFLOAD = 0x33
CMD_MENU_FIRST_ITEM = 0x34
CMD_MENU_LAST_ITEM = 0x35
CMD_MENU_PREV_ITEM = 0x36
CMD_MENU_NEXT_ITEM = 0x37
CMD_MENU_PREV_SETTING = 0x38
CMD_MENU_NEXT_SETTING = 0x39
CMD_SAY_LINE = 0x3a
CMD_SAY_ABOVE = 0x3b
CMD_SAY_BELOW = 0x3c
CMD_MUTE = 0x3d
CMD_SPKHOME = 0x3e
CMD_SWITCHVT_PREV = 0x3f
CMD_SWITCHVT_NEXT = 0x40
CMD_CSRJMP_VERT = 0x41
CMD_PASTE = 0x42
CMD_RESTARTBRL = 0x43
CMD_RESTARTSPEECH = 0x44
CMD_MAX = 0x44
BRL_FLG_REPEAT_INITIAL= 0x800000
BRL_FLG_REPEAT_DELAY = 0x400000
# The size of the physical display (width, height). The coordinate system of
# the display is set such that the upper left is (0,0), x values increase from
# left to right, and y values increase from top to bottom.
#
# For the purposes of testing w/o a braille display, we'll set the display
# size to width=32 and height=1.
#
# [[[TODO: WDW - Only a height of 1 is support at this time.]]]
#
_displaySize = [32, 1]
# The list of lines on the display. This represents the entire amount of data
# to be drawn on the display. It will be clipped by the viewport if too large.
#
_lines = []
# The region with focus. This will be displayed at the home position.
#
_regionWithFocus = None
# The viewport is a rectangular region of size _displaySize whose upper left
# corner is defined by the point (x, line number). As such, the viewport is
# identified solely by its upper left point.
#
_viewport = [0, 0]
# The callback to call on a BrlTTY input event. This is passed to
# the init method.
#
_callback = None
# If True, the given portion of the currently displayed line is showing
# on the display.
#
endIsShowing = False
beginningIsShowing = False
# 1-based offset saying which braille cell has the cursor. A value
# of 0 means no cell has the cursor.
#
cursorCell = 0
def _printBrailleEvent(level, command):
"""Prints out a Braille event. The given level may be overridden
if the eventDebugLevel (see debug.setEventDebugLevel) is greater in
debug.py.
Arguments:
- command: the BrlAPI command for the key that was pressed.
"""
debug.printInputEvent(
level,
"BRAILLE EVENT: %x" % command)
class Region:
"""A Braille region to be displayed on the display. The width of
each region is determined by its string.
"""
def __init__(self, string, cursorOffset=0):
"""Creates a new Region containing the given string.
Arguments:
- string: the string to be displayed
- cursorOffset: a 0-based index saying where to draw the cursor
for this Region if it gets focus.
"""
if not string:
string = ""
if string[-1:] == "\n":
string = string[:-1]
self.string = string
self.cursorOffset = cursorOffset
def processCursorKey(self, offset):
"""Processes a cursor key press on this Component. The offset is
0-based, where 0 represents the leftmost character of string
associated with this region. Note that the zeroeth character may have
been scrolled off the display."""
pass
class Component(Region):
"""A subclass of Region backed by an accessible. This Region will react
to any cursor routing key events and perform the default action on the
accessible, if a default action exists.
"""
def __init__(self, accessible, string, cursorOffset=0):
"""Creates a new Component.
Arguments:
- accessible: the accessible
- string: the string to use to represent the component
- cursorOffset: a 0-based index saying where to draw the cursor
for this Region if it gets focus.
"""
Region.__init__(self, string, cursorOffset)
self.accessible = accessible
def processCursorKey(self, offset):
"""Processes a cursor key press on this Component. The offset is
0-based, where 0 represents the leftmost character of string
associated with this region. Note that the zeroeth character may have
been scrolled off the display."""
actions = self.accessible.action
if actions:
actions.doAction(0)
else:
# [[[WDW - HACK to do a mouse button 1 click if we have
# to. For example, page tabs don't have any actions but
# we want to be able to select them with the cursor
# routing key.]]]
#
debug.println(debug.LEVEL_FINEST,
"braille.Component.processCursorKey: no action")
try:
eventsynthesizer.clickObject(self.accessible, 1)
except:
debug.printException(debug.LEVEL_SEVERE)
class Text(Region):
"""A subclass of Region backed by a Text object. This Region will
react to any cursor routing key events by positioning the caret in
the associated text object. The line displayed will be the
contents of the text object preceded by an optional label.
[[[TODO: WDW - need to add in text selection capabilities. Logged
as bugzilla bug 319754.]]]"""
def __init__(self, accessible, label=None):
"""Creates a new Text region.
Arguments:
- accessible: the accessible that implements AccessibleText
- label: an optional label to display
"""
self.accessible = accessible
[string, self.caretOffset, self.lineOffset] = \
util.getTextLineAtCaret(self.accessible)
# Sometimes, gnome-terminal will give us very odd values when
# the user is editing using 'vi' and has positioned the caret
# at the first character of the first line. In this case, we
# end up getting a very large negative number for the line offset.
# So, we just assume the user is at the first character.
#
if self.lineOffset < 0:
self.caretOffset = 0
self.lineOffset = 0
[string, startOffset, endOffset] = \
self.accessible.text.getTextAtOffset(
0,
atspi.Accessibility.TEXT_BOUNDARY_LINE_START)
cursorOffset = self.caretOffset - self.lineOffset
self.label = label
if self.label:
string = self.label + " " + string
cursorOffset += len(self.label) + 1
Region.__init__(self, string, cursorOffset)
def repositionCursor(self):
"""Attempts to reposition the cursor in response to a new
caret position. If it is possible (i.e., the caret is on
the same line as it was), reposition the cursor and return
True. Otherwise, return False.
"""
result = util.getTextLineAtCaret(self.accessible)
caretOffset = result[1]
lineOffset = result[2]
cursorOffset = caretOffset - lineOffset
if self.label:
cursorOffset += len(self.label) + 1
if lineOffset != self.lineOffset:
return False
else:
self.caretOffset = caretOffset
self.lineOffset = lineOffset
self.cursorOffset = cursorOffset
return True
def processCursorKey(self, offset):
"""Processes a cursor key press on this Component. The offset is
0-based, where 0 represents the leftmost character of text associated
with this region. Note that the zeroeth character may have been
scrolled off the display."""
if self.label:
offset = offset - len(self.label) - 1
if offset < 0:
return
newCaretOffset = self.lineOffset + offset
self.accessible.text.setCaretOffset(newCaretOffset)
class ReviewComponent(Component):
"""A subclass of Component that is to be used for flat review mode."""
def __init__(self, accessible, string, cursorOffset, zone):
"""Creates a new Component.
Arguments:
- accessible: the accessible
- string: the string to use to represent the component
- cursorOffset: a 0-based index saying where to draw the cursor
for this Region if it gets focus.
- zone: the flat review Zone associated with this component
"""
Component.__init__(self, accessible, string, cursorOffset)
self.zone = zone
class ReviewText(Region):
"""A subclass of Region backed by a Text object. This Region will
does not react to the caret changes, but will react if one updates
the cursorPosition. This class is meant to be used by flat review
mode to show the current character position.
"""
def __init__(self, accessible, string, lineOffset, zone):
"""Creates a new Text region.
Arguments:
- accessible: the accessible that implements AccessibleText
- string: the string to use to represent the component
- lineOffset: the character offset into where the text line starts
- zone: the flat review Zone associated with this component
"""
Region.__init__(self, string)
self.accessible = accessible
self.lineOffset = lineOffset
self.zone = zone
def processCursorKey(self, offset):
"""Processes a cursor key press on this Component. The offset is
0-based, where 0 represents the leftmost character of text associated
with this region. Note that the zeroeth character may have been
scrolled off the display."""
newCaretOffset = self.lineOffset + offset
self.accessible.text.setCaretOffset(newCaretOffset)
class Line:
"""A horizontal line on the display. Each Line is composed of a sequential
set of Regions.
"""
def __init__(self, region=None):
self.regions = []
self.string = ""
if region:
self.addRegion(region)
def addRegion(self, region):
self.regions.append(region)
def addRegions(self, regions):
self.regions.extend(regions)
def getLineInfo(self):
"""Computes the complete string for this line as well as a
0-based index where the focused region starts on this line.
If the region with focus is not on this line, then the index
will be -1.
Returns [string, offsetIndex]
"""
string = ""
focusOffset = -1
for region in self.regions:
if region == _regionWithFocus:
focusOffset = len(string)
if region.string:
# [[[TODO: WDW - HACK: Replace unicode ellipses with "..."
# The ultimate solution is to get i18n support into
# BrlTTY.]]]
#
string += region.string.replace("\342\200\246", "...")
return [string, focusOffset]
def getRegionAtOffset(self, offset):
"""Finds the Region at the given 0-based offset in this line.
Returns the [region, offsetinregion] where the region is
the region at the given offset, and offsetinregion is the
0-based offset from the beginning of the region, representing
where in the region the given offset is."""
# Translate the cursor offset for this line into a cursor offset
# for a region, and then pass the event off to the region for
# handling.
#
region = None
string = ""
pos = 0
for region in self.regions:
string = string + region.string
if len(string) > offset:
break
else:
pos = len(string)
return [region, offset - pos]
def processCursorKey(self, offset):
"""Processes a cursor key press on this Component. The offset is
0-based, where 0 represents the leftmost character of string
associated with this line. Note that the zeroeth character may have
been scrolled off the display."""
[region, regionOffset] = self.getRegionAtOffset(offset)
region.processCursorKey(regionOffset)
def getRegionAtCell(cell):
"""Given a 1-based cell offset, return the braille region
associated with that cell in the form of [region, offsetinregion]
where 'region' is the region associated with the cell and
'offsetinregion' is the 0-based offset of where the cell is
in the region, where 0 represents the beginning of the region, """
if len(_lines) > 0:
offset = (cell - 1) + _viewport[0]
lineNum = _viewport[1]
return _lines[lineNum].getRegionAtOffset(offset)
else:
return [None, -1]
def clear():
"""Clears the logical structure, but keeps the Braille display as is
(until a refresh operation).
"""
global _lines
global _regionWithFocus
global _viewport
_lines = []
_regionWithFocus = None
_viewport = [0, 0]
def setLines(lines):
global _lines
_lines = lines
def addLine(line):
"""Adds a line to the logical display for painting. The line is added to
the end of the current list of known lines. It is necessary for the
viewport to be over the lines and for refresh to be called for the new
line to be painted.
Arguments:
- line: an instance of Line to add.
"""
global _lines
_lines.append(line)
line._index = len(_lines)
def getShowingLine():
"""Returns the Line that is currently being painted on the display.
"""
return _lines[_viewport[1]]
def setFocus(region, panToFocus=True):
"""Specififes the region with focus. This region will be positioned
at the home position if panToFocus is True.
Arguments:
- region: the given region, which much be in a line that has been
added to the logical display
"""
global _regionWithFocus
_regionWithFocus = region
if not panToFocus or (not _regionWithFocus):
return
# Adjust the viewport according to the new region with focus.
# The goal is to have the first cell of the region be in the
# home position, but we will give priority to make sure the
# cursor for the region is on the display. For example, when
# faced with a long text area, we'll show the position with
# the caret vs. showing the beginning of the region.
lineNum = 0
done = False
for line in _lines:
for reg in line.regions:
if reg == _regionWithFocus:
_viewport[1] = lineNum
done = True
break
if done:
break
else:
lineNum += 1
line = _lines[_viewport[1]]
[string, offset] = line.getLineInfo()
# If the cursor is too far right, we scroll the viewport
# so the cursor will be on the last cell of the display.
#
if _regionWithFocus.cursorOffset >= _displaySize[0]:
offset += _regionWithFocus.cursorOffset - _displaySize[0] + 1
_viewport[0] = max(0, offset)
def refresh(panToCursor=True, targetCursorCell=0):
"""Repaints the Braille on the physical display. This clips the entire
logical structure by the viewport and also sets the cursor to the
appropriate location. [[[TODO: WDW - I'm not sure how BrlTTY handles
drawing to displays with more than one line, so I'm only going to handle
drawing one line right now.]]]
Arguments:
- panToCursor: if True, will adjust the viewport so the cursor is
showing.
- targetCursorCell: Only effective if panToCursor is True.
0 means automatically place the cursor somewhere
on the display so as to minimize movement but
show as much of the line as possible. A positive
value is a 1-based target cell from the left side
of the display and a negative value is a 1-based
target cell from the right side of the display.
"""
global endIsShowing
global beginningIsShowing
global cursorCell
global monitor
if len(_lines) == 0:
brl.writeText(0, "")
return
# Now determine the location of the cursor. First, we'll figure
# out the 1-based offset for where we want the cursor to be. If
# the target cell is less than zero, it means an offset from the
# right hand side of the display.
#
if targetCursorCell < 0:
targetCursorCell = _displaySize[0] + targetCursorCell + 1
# Now, we figure out the 0-based offset for where the cursor
# actually is in the string.
#
line = _lines[_viewport[1]]
[string, focusOffset] = line.getLineInfo()
cursorOffset = -1
if focusOffset >= 0:
cursorOffset = focusOffset + _regionWithFocus.cursorOffset
# Now, if desired, we'll automatically pan the viewport to show
# the cursor. If there's no targetCursorCell, then we favor the
# left of the display if we need to pan left, or we favor the
# right of the display if we need to pan right.
#
if panToCursor and (cursorOffset >= 0):
if len(string) <= _displaySize[0]:
_viewport[0] = 0
elif targetCursorCell:
_viewport[0] = max(0, cursorOffset - targetCursorCell + 1)
elif cursorOffset < _viewport[0]:
_viewport[0] = max(0, cursorOffset)
elif cursorOffset >= (_viewport[0] + _displaySize[0]):
_viewport[0] = max(0, cursorOffset - _displaySize[0] + 1)
startPos = _viewport[0]
endPos = startPos + _displaySize[0]
# Now normalize the cursor position to BrlTTY, which uses 1 as
# the first cursor position as opposed to 0.
#
cursorCell = cursorOffset - startPos
if (cursorCell < 0) or (cursorCell >= _displaySize[0]):
cursorCell = 0
else:
cursorCell += 1 # Normalize to 1-based offset
debug.println(debug.LEVEL_INFO, "BRAILLE LINE: '%s'" % string)
debug.println(debug.LEVEL_INFO, " VISIBLE: '%s', cursor=%d" \
% (string[startPos:endPos], cursorCell))
brl.writeText(cursorCell, string[startPos:endPos])
if settings.enableBrailleMonitor:
if not monitor:
monitor = brlmon.BrlMon(_displaySize[0])
monitor.show_all()
monitor.writeText(cursorCell, string[startPos:endPos])
elif monitor:
monitor.destroy()
beginningIsShowing = startPos == 0
endIsShowing = endPos >= len(string)
def displayRegions(regionInfo):
"""Displays a list of regions on a single line, setting focus to the
specified region. The regionInfo parameter is something that is
typically returned by a call to braillegenerator.getBrailleRegions.
Arguments:
- regionInfo: a list where the first element is a list of regions
to display and the second element is the region
with focus (must be in the list from element 0)
"""
regions = regionInfo[0]
focusedRegion = regionInfo[1]
clear()
line = Line()
for item in regions:
line.addRegion(item)
addLine(line)
setFocus(focusedRegion)
refresh()
def displayMessage(message, cursor=-1):
"""Displays a single line, setting the cursor to the given position,
ensuring that the cursor is in view.
Arguments:
- message: the string to display
- cursor: the 0-based cursor position, where -1 (default) means no cursor
"""
clear()
region = Region(message, cursor)
addLine(Line(region))
setFocus(region)
refresh(True)
def panLeft(panAmount=0):
"""Pans the display to the left, limiting the pan to the beginning
of the line being displayed.
Arguments:
- panAmount: the amount to pan. A value of 0 means the entire
width of the physical display.
Returns True if a pan actually happened.
"""
oldX = _viewport[0]
if panAmount == 0:
panAmount = _displaySize[0]
if _viewport[0] > 0:
_viewport[0] = max(0, _viewport[0] - panAmount)
return oldX != _viewport[0]
def panRight(panAmount=0):
"""Pans the display to the right, limiting the pan to the length
of the line being displayed.
Arguments:
- panAmount: the amount to pan. A value of 0 means the entire
width of the physical display.
Returns True if a pan actually happened.
"""
oldX = _viewport[0]
if panAmount == 0:
panAmount = _displaySize[0]
if len(_lines) > 0:
lineNum = _viewport[1]
newX = _viewport[0] + panAmount
[string, focusOffset] = _lines[lineNum].getLineInfo()
if newX < len(string):
_viewport[0] = newX
return oldX != _viewport[0]
def panToOffset(offset):
"""Automatically pan left or right to make sure the current offset is
showing."""
while offset < _viewport[0]:
debug.println(debug.LEVEL_FINEST,
"braille.panToOffset (left) %d" % offset)
if not panLeft():
break
while offset >= (_viewport[0] + _displaySize[0]):
debug.println(debug.LEVEL_FINEST,
"braille.panToOffset (right) %d" % offset)
if not panRight():
break
def returnToRegionWithFocus(inputEvent=None):
"""Pans the display so the region with focus is displayed.
Arguments:
- inputEvent: the InputEvent instance that caused this to be called.
Returns True to mean the command should be consumed.
"""
setFocus(_regionWithFocus)
refresh(True)
return True
def _processBrailleEvent(command):
"""Handles BrlTTY command events. This passes commands on to Orca for
processing. If Orca does not handle them (as indicated by a return value
of false from the callback passed to init, it will attempt to handle the
command itself - either by panning the viewport or passing cursor routing
keys to the Regions for handling.
Arguments:
- command: the BrlAPI command for the key that was pressed.
"""
_printBrailleEvent(debug.LEVEL_FINE, command)
# [[[TODO: WDW - DaveM suspects the Alva driver is sending us a
# repeat flag. So...let's kill a couple birds here until BrlTTY
# 3.8 fixes the problem: we'll disable autorepeat and we'll also
# strip out the autorepeat flag if this is the first press of a
# button.]]]
#
if command & BRL_FLG_REPEAT_INITIAL:
command &= ~(BRL_FLG_REPEAT_INITIAL | BRL_FLG_REPEAT_DELAY)
elif command & BRL_FLG_REPEAT_DELAY:
return True
consumed = False
if settings.timeoutCallback and (settings.timeoutTime > 0):
signal.signal(signal.SIGALRM, settings.timeoutCallback)
signal.alarm(settings.timeoutTime)
if _callback:
try:
# Like key event handlers, a return value of True means
# the command was consumed.
#
consumed = _callback(command)
except:
debug.printException(debug.LEVEL_WARNING)
consumed = False
if (command >= 0x100) and (command < (0x100 + _displaySize[0])):
if len(_lines) > 0:
cursor = (command - 0x100) + _viewport[0]
lineNum = _viewport[1]
_lines[lineNum].processCursorKey(cursor)
consumed = True
if settings.timeoutCallback and (settings.timeoutTime > 0):
signal.alarm(0)
return consumed
def init(callback=None, tty=7):
"""Initializes the braille module, connecting to the BrlTTY driver.
Arguments:
- callback: the method to call with a BrlTTY input event.
- tty: the tty port to take ownership of (default = 7)
Returns True if the initialization procedure was run or False if this
module has already been initialized.
"""
global _initialized
global _displaySize
global _callback
if _initialized:
return False
_callback = callback
if brl.init(tty):
debug.println(debug.LEVEL_CONFIGURATION,
"Braille module has been initialized.")
brl.registerCallback(_processBrailleEvent)
else:
debug.println(debug.LEVEL_CONFIGURATION,
"Braille module has NOT been initialized.")
return False
# [[[TODO: WDW - For some reason, BrlTTY wants to say the height of the
# Vario is 40 so we hardcode it to 1 for now.]]]
#
#_displaySize = (brl.getDisplayWidth(), brl.getDisplayHeight())
_displaySize = [brl.getDisplayWidth(), 1]
debug.println(debug.LEVEL_CONFIGURATION,
"braille display size = (%d, %d)" \
% (_displaySize[0], _displaySize[1]))
clear()
refresh(True)
_initialized = True
return True
def shutdown():
"""Shuts down the braille module. Returns True if the shutdown procedure
was run or False if this module has not been initialized.
"""
global _initialized
if not _initialized:
return False
brl.shutdown()
_initialized = False
return True
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