All 7 sub-phases (4.1-4.7) are now fully implemented:
- 4.1 Glyph to Span Merging: grouping consecutive glyphs into spans
- 4.2 Line Formation: baseline clustering and direction detection
- 4.3 Column Detection: histogram-based gap analysis
- 4.4 Block Formation: paragraph/heading/list/table/caption/figure/code classification
- 4.5 Reading Order: XY-cut algorithm with Docstrum fallback
- 4.6 Output Serialization: plain text projection with configurable filters
- 4.7 Text Readability: composite scoring and correction pipeline
Closes pdftract-4k1x4. Verification: notes/pdftract-4k1x4.md.
Changes:
- extract.rs: integrate Phase 4 modules into main pipeline
- layout/correction.rs: expand correction pipeline with 2048 lines of tests
- layout/readability.rs: five-signal scoring with char-weighted median
- text.rs: plain text serialization with page breaks and filters
- span/mod.rs: Span struct with flags and confidence tracking
- layout/columns.rs: column assignment to lines and spans
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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