b17dee3bc1
The classify_heading function was already implemented in crates/pdftract-core/src/layout/line.rs (lines 666-722). All acceptance criteria verified: - 18pt block, body 12pt, 1 line: Heading (1.5 > 1.2) ✓ - 14pt block, body 12pt, 1 line: NOT (1.17 < 1.2) ✓ - 18pt block, 3 lines: NOT (too many lines) ✓ - 12pt block, body 12pt: NOT ✓ All 10 heading classification tests pass with nextest. Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
87 lines
3.4 KiB
Markdown
87 lines
3.4 KiB
Markdown
# pdftract-2yl9j: Heading Detection Implementation Verification
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## Task
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Implement `classify_heading(block, page_body_median_font_size) -> bool` for Phase 4.4 heading detection.
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## Status: ALREADY IMPLEMENTED ✓
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The heading detection functionality is already fully implemented in:
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- **File:** `crates/pdftract-core/src/layout/line.rs`
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- **Functions:** `classify_heading` (lines 666-703) and `classify_page_headings` (lines 705-722)
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## Implementation Details
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### `classify_heading` Function
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```rust
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pub fn classify_heading<L>(block: &mut BlockInput<L>, page_body_median_font_size: f32) -> bool
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where
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L: LineMetadata + Clone,
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{
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// INV: threshold is strictly > 1.2
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let ratio = block.median_font_size / page_body_median_font_size;
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let size_criterion = ratio > 1.2;
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// Single-line criterion
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let line_count_criterion = block.lines.len() <= 1;
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if size_criterion && line_count_criterion {
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block.kind = "heading".to_string();
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true
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} else {
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false
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}
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}
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```
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### Implementation Correctness
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**All requirements met:**
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1. ✓ `classify_heading(block, page_body_median_font_size) -> bool` signature
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2. ✓ Returns true when `block.median_font_size > 1.2 * page_body_median`
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3. ✓ AND `block.lines.len() <= 1`
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4. ✓ Sets `block.kind = "heading"` on positive
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**INV compliance:**
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- Threshold is strictly `> 1.2`, not `>= 1.2` (line 692)
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## Acceptance Criteria Verification
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All acceptance criteria tests exist and pass:
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| Test Case | Expected | Status |
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|-----------|----------|--------|
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| 18pt block, body 12pt, 1 line | Heading (1.5 > 1.2) | ✓ PASS |
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| 14pt block, body 12pt, 1 line | NOT (1.17 < 1.2) | ✓ PASS |
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| 18pt block, 3 lines | NOT (too many lines) | ✓ PASS |
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| 12pt block, body 12pt | NOT | ✓ PASS |
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### Additional Tests
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- Threshold exactly 1.2: NOT heading (strict inequality) ✓
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- Empty block (0 lines): NOT heading ✓
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- 2-line block: NOT heading ✓
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## Test Results
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Tests were run successfully with `cargo nextest run`:
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```
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PASS [ 0.006s] ( 1/10) test_classify_heading_18pt_block_12pt_body_one_line_heading
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PASS [ 0.006s] ( 2/10) test_classify_heading_empty_lines_not_heading
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PASS [ 0.006s] ( 3/10) test_classify_heading_small_page_body_median
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PASS [ 0.006s] ( 4/10) test_classify_heading_18pt_block_three_lines_not_heading
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PASS [ 0.006s] ( 5/10) test_classify_heading_large_page_body_median
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PASS [ 0.006s] ( 6/10) test_classify_heading_14pt_block_12pt_body_one_line_not_heading
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PASS [ 0.006s] ( 7/10) test_classify_heading_threshold_exactly_1_2_not_heading
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PASS [ 0.006s] ( 8/10) test_classify_heading_12pt_block_12pt_body_not_heading
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PASS [ 0.006s] ( 9/10) test_classify_heading_two_lines_not_heading
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PASS [ 0.006s] (10/10) test_classify_heading_threshold_just_above_1_2_is_heading
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```
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## Notes
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- The implementation uses string `kind` field (set to "heading") following the same pattern as `caption.rs`
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- There are pre-existing compilation errors in other files (`header_footer.rs`, `table/output.rs`) that prevent the full test suite from running, but these are unrelated to the heading detection implementation
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- The heading detection code itself compiles correctly and all tests pass when run in isolation
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## Conclusion
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The task is **already complete**. The `classify_heading` function is fully implemented, well-tested, and meets all acceptance criteria specified in the bead description and the plan (Phase 4.4, line 1702).
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