improved documentation for the diff generation.
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Storm Dragon
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6998706934
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b0ac6e1409
@ -233,57 +233,110 @@ class attributeManager():
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return attributeFormatString
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def trackHighlights(self):
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"""
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Detects text with changed attributes (highlighting) between screen updates.
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This is crucial for screen readers to announce when text becomes highlighted,
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selected, or changes visual emphasis (bold, reverse video, color changes, etc.)
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Returns:
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tuple: (highlighted_text, cursor_position)
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- highlighted_text: string of characters that gained highlighting
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- cursor_position: dict {'x': col, 'y': row} of first highlighted char
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"""
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result = ''
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currCursor = None
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# screen change
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# Early exit conditions - no attribute comparison possible
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if self.prevAttributes == None:
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# First screen load - no previous attributes to compare against
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return result, currCursor
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# no change
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if self.prevAttributes == self.currAttributes:
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# No attribute changes detected
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return result, currCursor
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# error case
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if self.currAttributes == None:
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# Error condition - current attributes missing
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return result, currCursor
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# special case for pty if not text exists.
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if len(self.currAttributes) == 0:
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# Special case for PTY environments with no text content
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return result, currCursor
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# Get current screen text to correlate with attribute changes
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text = self.env['runtime']['screenManager'].getScreenText()
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textLines = text.split('\n')
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# Sanity check: text lines must match attribute array dimensions
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if len(textLines) != len(self.currAttributes):
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return result, currCursor
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# Compare attributes line by line, character by character
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for line in range(len(self.prevAttributes)):
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if self.prevAttributes[line] != self.currAttributes[line]:
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# This line has attribute changes - examine each character position
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for column in range(len(self.prevAttributes[line])):
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if self.prevAttributes[line][column] == self.currAttributes[line][column]:
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# No change at this position
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continue
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# Attribute changed at this position - check if it's worth announcing
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if self.isUsefulForTracking(line, column, self.currAttributes, self.prevAttributes):
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# First highlighted character becomes cursor position for navigation
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if not currCursor:
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currCursor = {'x': column, 'y': line}
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# Accumulate highlighted characters
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result += textLines[line][column]
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# Add space between lines of highlighted text for speech clarity
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result += ' '
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return result, currCursor
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def isUsefulForTracking(self, line, column, currAttributes, prevAttributes, attribute=1 , mode = 'zaxe'):
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"""
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Determines if an attribute change at a specific position is worth announcing.
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This prevents announcing every minor attribute change and focuses on meaningful
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highlighting that indicates user selections, focus changes, or important emphasis.
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Args:
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line, column: Position of the attribute change
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currAttributes, prevAttributes: Current and previous attribute arrays
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attribute: Which attribute to examine (1=background color by default)
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mode: Detection algorithm ('zaxe', 'default', 'barrier')
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Returns:
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bool: True if this attribute change should be announced to user
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"""
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# Sanity checks for valid position and sufficient screen content
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if len(currAttributes) <= 3:
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return False
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if line < 0:
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return False
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if line > len(currAttributes):
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return False
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useful = False
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if mode == 'default':
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# non default tracking
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# Simple mode: announce any non-default attribute
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useful = not self.isDefaultAttribute(currAttributes[line][column])
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elif (mode == 'zaxe') or (mode == ''):
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# arround me tracking for bg
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# Context-aware mode: only announce attributes that stand out from surroundings
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# This prevents announcing entire blocks of highlighted text character by character
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# by checking if the attribute differs from adjacent lines
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if line == 0:
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useful = (currAttributes[line][column][attribute] != currAttributes[line + 1][column][attribute]) and (currAttributes[line][column][attribute] != currAttributes[line + 2][column][attribute])
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# Top line: compare against lines below
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useful = (currAttributes[line][column][attribute] != currAttributes[line + 1][column][attribute]) and \
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(currAttributes[line][column][attribute] != currAttributes[line + 2][column][attribute])
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elif line >= len(prevAttributes):
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useful = (currAttributes[line][column][attribute] != currAttributes[line - 1][column][attribute]) and (currAttributes[line][column][attribute] != currAttributes[line - 2][column][attribute])
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# Bottom line: compare against lines above
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useful = (currAttributes[line][column][attribute] != currAttributes[line - 1][column][attribute]) and \
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(currAttributes[line][column][attribute] != currAttributes[line - 2][column][attribute])
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else:
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useful = (currAttributes[line][column][attribute] != currAttributes[line + 1][column][attribute]) and (currAttributes[line][column][attribute] != currAttributes[line - 1][column][attribute])
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# Middle lines: compare against both directions
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useful = (currAttributes[line][column][attribute] != currAttributes[line + 1][column][attribute]) and \
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(currAttributes[line][column][attribute] != currAttributes[line - 1][column][attribute])
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elif mode == 'barrier':
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# to be implement
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# Barrier mode: future enhancement for detecting screen boundaries/separators
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useful = True
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return useful
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@ -120,47 +120,94 @@ class screenManager():
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self.env['screen']['newDelta'] = ''
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self.env['runtime']['attributeManager'].resetAttributeDelta()
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# changes on the screen
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# Diff generation - critical for screen reader functionality
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# This code detects and categorizes screen content changes to provide appropriate
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# speech feedback (typing echo vs incoming text vs screen updates)
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# Pre-process screen text for comparison - collapse multiple spaces to single space
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# This normalization prevents spurious diffs from spacing inconsistencies
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oldScreenText = re.sub(' +',' ',self.env['runtime']['screenManager'].getWindowAreaInText(self.env['screen']['oldContentText']))
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newScreenText = re.sub(' +',' ',self.env['runtime']['screenManager'].getWindowAreaInText(self.env['screen']['newContentText']))
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# Track whether this appears to be typing (user input) vs other screen changes
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typing = False
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diffList = []
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if (self.env['screen']['oldContentText'] != self.env['screen']['newContentText']):
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# Special case: Initial screen content (going from empty to populated)
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# This handles first screen load or TTY switch scenarios
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if self.env['screen']['newContentText'] != '' and self.env['screen']['oldContentText'] == '':
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if oldScreenText == '' and\
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newScreenText != '':
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self.env['screen']['newDelta'] = newScreenText
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else:
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# Calculate byte positions for the current cursor's line in the flat text buffer
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# Formula: (line_number * columns) + line_number accounts for newlines
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# Each line contributes 'columns' chars + 1 newline char
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cursorLineStart = self.env['screen']['newCursor']['y'] * self.env['screen']['columns'] + self.env['screen']['newCursor']['y']
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cursorLineEnd = cursorLineStart + self.env['screen']['columns']
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# TYPING DETECTION ALGORITHM
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# Determines if this screen change is likely user typing vs other content changes
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# All conditions must be met for typing detection:
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if abs(self.env['screen']['oldCursor']['x'] - self.env['screen']['newCursor']['x']) >= 1 and \
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self.env['screen']['oldCursor']['y'] == self.env['screen']['newCursor']['y'] and \
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self.env['screen']['newContentText'][:cursorLineStart] == self.env['screen']['oldContentText'][:cursorLineStart] and \
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self.env['screen']['newContentText'][cursorLineEnd:] == self.env['screen']['oldContentText'][cursorLineEnd:]:
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# Condition 1: Cursor moved horizontally by at least 1 position (typical of typing)
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# Condition 2: Cursor stayed on same line (typing doesn't usually change lines)
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# Condition 3: Content BEFORE cursor line is unchanged (text above typing area)
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# Condition 4: Content AFTER cursor line is unchanged (text below typing area)
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# Together: only the current line changed, cursor moved horizontally = likely typing
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# Optimize diff calculation for typing by focusing on a small window around cursor
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cursorLineStartOffset = cursorLineStart
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cursorLineEndOffset = cursorLineEnd
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# Limit analysis window to avoid processing entire long lines
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# +3 provides safety buffer beyond cursor position to catch edge cases
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if cursorLineEnd > cursorLineStart + self.env['screen']['newCursor']['x'] + 3:
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cursorLineEndOffset = cursorLineStart + self.env['screen']['newCursor']['x'] + 3
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# Extract just the relevant text sections for character-level diff
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oldScreenText = self.env['screen']['oldContentText'][cursorLineStartOffset:cursorLineEndOffset]
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newScreenText = self.env['screen']['newContentText'][cursorLineStartOffset:cursorLineEndOffset]
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# Character-level diff for typing detection (not line-level)
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diff = self.differ.compare(oldScreenText, newScreenText)
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diffList = list(diff)
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typing = True
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# Validate typing assumption by checking if detected changes match cursor movement
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tempNewDelta = ''.join(x[2:] for x in diffList if x[0] == '+')
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if tempNewDelta.strip() != '':
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if tempNewDelta != ''.join(newScreenText[self.env['screen']['oldCursor']['x']:self.env['screen']['newCursor']['x']].rstrip()):
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# Compare diff result against expected typing pattern
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# Expected: characters between old and new cursor positions
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expectedTyping = ''.join(newScreenText[self.env['screen']['oldCursor']['x']:self.env['screen']['newCursor']['x']].rstrip())
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# If diff doesn't match expected typing pattern, treat as general screen change
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if tempNewDelta != expectedTyping:
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# Fallback: treat entire current line as new content
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diffList = ['+ ' + self.env['screen']['newContentText'].split('\n')[self.env['screen']['newCursor']['y']] +'\n']
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typing = False
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else:
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# GENERAL SCREEN CHANGE DETECTION
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# Not typing - handle as line-by-line content change
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# This catches: incoming messages, screen updates, application output, etc.
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diff = self.differ.compare(oldScreenText.split('\n'),\
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newScreenText.split('\n'))
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diffList = list(diff)
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# Extract added and removed content from diff results
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# Output format depends on whether this was detected as typing or general change
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if not typing:
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# Line-based changes: join with newlines for proper speech cadence
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self.env['screen']['newDelta'] = '\n'.join(x[2:] for x in diffList if x[0] == '+')
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else:
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# Character-based changes: no newlines for smooth typing echo
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self.env['screen']['newDelta'] = ''.join(x[2:] for x in diffList if x[0] == '+')
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# Negative delta (removed content) - used for backspace/delete detection
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self.env['screen']['newNegativeDelta'] = ''.join(x[2:] for x in diffList if x[0] == '-')
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# track highlighted
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