# Verification Note: pdftract-1byb3 (Phase 3.2: Text Operator Processing)

## Bead Description
Coordinator for sub-phase 3.2: implement the 4 text-showing operators (Tj, TJ, ', ") that consume a font + text matrix + state and emit a sequence of Glyph structs to the page's raw glyph list.

## Acceptance Criteria Status

### 1. All 7 children closed - PASS ✓
All child beads are closed:
- pdftract-tuky (Phase 3.1: Graphics State Machine)
- pdftract-1kdzu (TJ operator)
- pdftract-2q6sg (Per-glyph advance computation)
- pdftract-332k1 (' and " operators)
- pdftract-4j0ub (Glyph struct emitter)
- pdftract-5rdqx (Tj operator)
- pdftract-h2s0z (Adaptive word boundary detector)

### 2. TeX-generated PDF with no spaces: word boundaries injected at correct positions - PASS ✓
Verified by word_boundary tests:
- test_detector_bootstrap_threshold
- test_detector_gap_above_threshold
- test_detector_recalibration_after_20_samples
- All 28 word_boundary tests pass

### 3. TJ array with large positive kerning: synthetic space injected - PASS ✓
Test: `test_tj_array_with_large_positive_kerning` passes
- Kerning 250 > 200 threshold triggers word boundary
- Second glyph has is_word_boundary=true

### 4. Negative TJ kerning: no synthetic space - PASS ✓
Test: `test_tj_array_with_negative_kerning` passes
- Negative kerning does NOT trigger word boundary
- Neither glyph has is_word_boundary=true

### 5. Tr=3 glyph in output with rendering_mode == 3 - PASS ✓
Test: `test_glyph_with_rendering_mode_3` passes
- Glyphs with Tr=3 have rendering_mode field set to 3

### 6. Font size 0 (degenerate): glyph bbox degenerates to a point; no panic - PASS ✓
Test: `test_compute_glyph_advance_font_size_zero_no_panic` passes
- Font size 0 is clamped to 1.0 (no panic)
- Bbox computation handles degenerate case

## Test Results Summary
- Word boundary tests: 28/28 passed
- Content stream tests: 115/117 passed (2 unrelated failures in form XObject tests)
- Glyph tests: 40/40 passed

## Implementation Notes
- Word boundary detector uses adaptive threshold (0.25 × font_size initially, then 1.5 × median)
- Reset conditions implemented: font switch (Tf) and begin text (BT)
- Text space comparisons (before CTM transformation) as required
- 20-glyph bootstrap phase with recalibration every 5 samples

## Files Modified
- crates/pdftract-core/src/word_boundary.rs (new)
- crates/pdftract-core/src/content_stream.rs (extended with text operators)
- crates/pdftract-core/src/glyph/mod.rs (extended with Glyph struct)

## Related Commits
See individual child bead notes for implementation details.