c2fed3d010
All 4 children verified closed: - pdftract-56vwd: x0 histogram builder (7 tests PASS) - pdftract-14w0w: Gap detection (13 tests PASS) - pdftract-2rkc1: Column confirmation (14 tests PASS) - pdftract-64j83: Column label assignment (5 tests PASS) Total: 49 column tests PASS. Acceptance criteria verified for: - Three-column layout detection - Full-width heading handling - Single-column page (no false splits) Closes pdftract-63ka2
73 lines
2.9 KiB
Markdown
73 lines
2.9 KiB
Markdown
# pdftract-63ka2: Phase 4.3 Column Detection (coordinator)
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## Summary
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Coordinator for Phase 4.3 Column Detection. All 4 child beads are closed with implementation and tests verified.
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## Children Status
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| Child ID | Title | Status | Verified |
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|----------|-------|--------|----------|
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| pdftract-56vwd | x0 histogram builder (1pt resolution) | closed | ✓ May 25 |
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| pdftract-14w0w | Gap detection (>= 0.03 * page_width) | closed | ✓ May 27 |
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| pdftract-2rkc1 | Column confirmation (>= 3 lines) | closed | ✓ May 27 |
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| pdftract-64j83 | Column label assignment to spans/lines | closed | ✓ May 24 |
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## Acceptance Criteria Verification
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### Criterion 1: All 4 children closed
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**Status:** PASS
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All 4 children have been closed with verification notes documenting their implementation and test coverage.
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### Criterion 2: Three-column academic paper detected
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**Status:** PASS (verified via `test_confirm_columns_three_column_all_confirmed`)
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Test creates 3-column layout with gaps at 200-219 and 400-419, 10 lines per column.
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Confirmed output: 3 columns with indices 0, 1, 2 and x_ranges [0,200), [220,400), [420,600).
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### Criterion 3: Full-width heading above two-column body
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**Status:** PASS (verified via `test_assign_columns_to_lines_full_width_heading`)
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Test verifies that when all spans on a line have `column = None` (full-width heading), the line's column is also `None`. Body spans in columns 0 and 1 are correctly assigned.
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### Criterion 4: Single-column page: no false splits
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**Status:** PASS (verified via `test_assign_columns_to_spans_single_column`)
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Test confirms single-column page (full-width x_range [0,600)) assigns all spans to `Some(0)`.
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Also verified by `test_confirm_columns_single_column_confirmed`.
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## Test Coverage Summary
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Total column tests: **49 tests, all PASS**
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- `build_x0_histogram`: 7 tests
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- `detect_column_gaps`: 13 tests
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- `confirm_columns`: 14 tests
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- `assign_columns_to_spans`: 5 tests
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- `assign_columns_to_lines`: 5 tests
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- Supporting tests: 5 tests
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## Implementation Location
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All code in `crates/pdftract-core/src/layout/columns.rs`:
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- `build_x0_histogram()` - lines 48-82
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- `detect_column_gaps()` - lines 156-201
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- `confirm_columns()` - lines 252-332
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- `assign_columns_to_spans()` - lines 428-437
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- `assign_columns_to_lines()` - lines 464-491
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- Supporting types: `ColumnGap`, `Column`, `CandidateColumn`
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- Traits: `HasBBox`, `HasFirstSpan`, `HasBBoxAndColumn`, `HasSpansWithColumn`
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## Critical Invariants Verified
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- **3-line minimum:** Enforced in `confirm_columns` filter (line 326)
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- **Column gap threshold scales with page_width:** `(page_width * 0.03).ceil()` (line 157)
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- **Full-width lines get column = None:** >50% dominance check in `assign_columns_to_lines`
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- **Column indices monotonic left-to-right:** Verified in tests
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## Gates to Next Phase
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This coordinator completion gates:
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- Phase 4.4: Per-column block formation
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- Phase 4.5: XY-cut reading order
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