Changelog

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0.6.0

Major accuracy improvements to the redline extraction algorithm. On a sample of 50 redline PDFs, capture rate improved from 53.5% to 98.4%.

Text extraction overhaul

  • Replaced device-level span boundaries with MuPDF's structured text (stext) line/style grouping, matching the same text model PyMuPDF uses internally
  • Synthesize space characters by glyph geometry, fixing missing spaces throughout extracted text
  • Adaptive intervening-text break thresholds to correctly split segments separated by uncolored content (email/token mode at 2.3x, punctuation at 2.5x, name boundaries at 3.2x, prose at 5.0x)

Pairing improvements

  • Fixed x-gap calculation to measure from segment end (not start), preventing false pairings
  • Tightened pair_x_gap_max from 3.0 to 1.5 points to avoid pairing adjacent but unrelated items
  • Sort deletions first to match Python pairing order
  • Allow overlapping deletion/insertion positions

Color handling

  • Use MuPDF's ICC-aware color conversion (Colorspace::convert_color) instead of naive CMYK-to-RGB formula, fixing missed redlines in CMYK documents

Segment boundary fixes

  • Strip font subset prefixes (e.g. UFLVUZ+) in style key to prevent fragmentation across font subsets
  • Flush segments on backward x-jumps to handle overlaid duplicate text layers
  • Add name boundary break heuristic for table layouts with adjacent names
  • Add comma to punctuation break list

0.5.0

  • Initial release