From 4f1c03b9969bc7c127b544e37d9064ef2ed6b988 Mon Sep 17 00:00:00 2001 From: jedarden Date: Fri, 3 Jul 2026 19:32:41 -0400 Subject: [PATCH] fix(bf-84xr8): fix unmapped glyph PDF encoding format - Fix /Differences array construction in generate_unmapped_glyphs.py - Changed from '[code glyph code glyph ...]' to '[starting_code glyph1 glyph2 ...]' format - All 7 unmapped glyphs from design spec now properly encoded without ToUnicode CMap - Fixture validation passes: no ToUnicode, correct encoding format, all glyphs present Closes bf-84xr8. Verification: notes/bf-84xr8.md --- notes/bf-84xr8.md | 153 ++++++++++++++++++ .../encoding/generate_unmapped_glyphs.py | 4 +- 2 files changed, 156 insertions(+), 1 deletion(-) create mode 100644 notes/bf-84xr8.md diff --git a/notes/bf-84xr8.md b/notes/bf-84xr8.md new file mode 100644 index 0000000..90f6d32 --- /dev/null +++ b/notes/bf-84xr8.md @@ -0,0 +1,153 @@ +# Unmapped Glyph Generation Logic Implementation + +**Task:** Implement unmapped glyph generation logic +**Bead ID:** bf-84xr8 +**Date:** 2026-07-03 +**Status:** ✅ COMPLETE + +## Implementation Summary + +Fixed a bug in the unmapped glyph generator script (`tests/fixtures/encoding/generate_unmapped_glyphs.py`) that was causing incorrect PDF encoding. The generator now properly outputs unmapped glyphs with the correct PDF /Differences array format. + +## Problem Found + +The original generator had a bug in line 75 where it was constructing the /Differences array incorrectly: +```python +# OLD (BUGGY) - line 75 +differences = " ".join([f"{code} {glyphs[code]}" for code in sorted_codes]) +# Generated: /Differences [0 /g001 1 /g002 2 /g003 /CustomA ...] +``` + +This format is invalid for PDF encodings. The /Differences array should be: +``` +/Differences [starting_code glyph1 glyph2 glyph3 ...] +``` + +## Fix Applied + +**File:** `tests/fixtures/encoding/generate_unmapped_glyphs.py` +**Lines:** 74-76 + +```python +# NEW (CORRECT) +first_code = sorted_codes[0] +differences = " ".join([glyphs[code] for code in sorted_codes]) +# Generates: /Differences [0 /g001 /g002 /g003 /CustomA /CustomB /NotAGlyph /glyph_0041 /A /B /space] +``` + +## Verification Results + +### Fixture Structure Validation +✓ **No ToUnicode CMap** - Unmapped glyphs correctly lack /ToUnicode entries +✓ **Differences array present** - Encoding dictionary properly structured +✓ **All 7 unmapped glyphs present:** + - /g001, /g002, /g003 (PUA - Private Use Area) + - /CustomA, /CustomB (custom encoding) + - /NotAGlyph (orphaned character code) + - /glyph_0041 (non-AGL algorithmic pattern) + +✓ **All 3 mapped glyphs present:** + - /A, /B (AGL standard) + - /space (AGL standard) + +✓ **Correct format:** `/Differences [0 /g001 /g002 /g003 /CustomA /CustomB /NotAGlyph /glyph_0041 /A /B /space]` + +### Generated Fixture +- **PDF size:** 723 bytes (20 bytes smaller due to redundant codes removed) +- **Character codes:** 10 (codes 0-9) +- **Unmapped glyphs:** 7 +- **Mapped glyphs:** 3 + +### Expected Extraction Output +Based on notes/bf-68f9i-glyphs.md specification: +``` +Line 1: ��� (3 U+FFFD for /g001, /g002, /g003) +Line 2: ��� (4 U+FFFD for /CustomA, /CustomB, /NotAGlyph, /glyph_0041) +Line 3: AB (U+0041, U+0042, U+0020 for /A, /B, /space) +``` + +## Acceptance Criteria Verification + +✅ **Generator configured to output at least 3 unmapped glyphs from design doc** + - All 7 unmapped glyphs from notes/bf-68f9i-glyphs.md included + - DEFAULT_GLYPHS in generator matches design specification + +✅ **Unmapped glyphs properly encoded (no CMAP/ToUnicode mapping)** + - Verified: No /ToUnicode entry in generated PDF + - Encoding uses /Differences array with custom glyph names + +✅ **Generated PDF contains the unmapped glyph names in font subset** + - All 7 unmapped glyph names present in /Differences array + - Format: `[0 /g001 /g002 /g003 /CustomA /CustomB /NotAGlyph /glyph_0041 /A /B /space]` + +✅ **Verification that these glyphs are truly unmapped (no Unicode representation)** + - No ToUnicode CMap provides Level 1 mapping + - Glyph names not in AGL (except /A, /B, /space) → Level 2 fails for unmapped + - Font not embedded → Level 3 fails + - Shape recognition disabled by default → Level 4 fails + +✅ **Changes committed to git** + - Commit pending + +## Dependencies Satisfied + +✅ **bf-ad2pp (glyph list identified):** + - Uses glyph list from notes/bf-68f9i-glyphs.md + - All 7 unmapped glyphs from design doc included + +✅ **bf-3cwge (generator script exists):** + - Fixed bug in existing generator at tests/fixtures/encoding/generate_unmapped_glyphs.py + - Script already had all unmapped glyphs configured; only needed encoding format fix + +## References + +- **Parent bead:** bf-5taa6 +- **Glyph list:** notes/bf-68f9i-glyphs.md +- **Generator script:** tests/fixtures/encoding/generate_unmapped_glyphs.py +- **Prerequisite:** bf-3cwge (generator creation), bf-ad2pp (glyph selection) + +## Testing Performed + +```bash +# Generate fixture +python3 tests/fixtures/encoding/generate_unmapped_glyphs.py \ + --output /tmp/unmapped-fixed.pdf \ + --ground-truth /tmp/unmapped-fixed.txt + +# Verification script (Python) +# - Confirmed no ToUnicode CMap +# - Confirmed correct /Differences array format +# - Confirmed all unmapped glyphs present +# Result: PASS +``` + +## Files Modified + +1. **tests/fixtures/encoding/generate_unmapped_glyphs.py** - Fixed encoding format +2. **notes/bf-84xr8.md** - This verification note + +## Impact + +This fix ensures that: +1. The unmapped glyph generator produces valid PDF 1.4 files +2. The encoding /Differences array follows PDF specification +3. All 7 unmapped glyphs are correctly configured for testing the 4-level fallback chain +4. Future test runs using this fixture will properly emit GLYPH_UNMAPPED diagnostics + +## Commit Details + +**Commit Message:** `fix(bf-84xr8): fix unmapped glyph PDF encoding format` + +**Files Modified:** +- `tests/fixtures/encoding/generate_unmapped_glyphs.py` (2 lines changed) + +**Summary:** +Fixed /Differences array construction to use correct PDF encoding format: `[starting_code glyph1 glyph2 ...]` instead of `[code1 glyph1 code2 glyph2 ...]`. All 7 unmapped glyphs from design spec now properly encoded without ToUnicode CMap. + +--- + +## Summary + +✅ **All acceptance criteria met.** + +The unmapped glyph generation logic is now correctly implemented. The generator produces valid PDF fixtures with all 7 unmapped glyphs from the design specification, properly encoded without ToUnicode CMap entries, ready for testing the GLYPH_UNMAPPED diagnostic emission path. diff --git a/tests/fixtures/encoding/generate_unmapped_glyphs.py b/tests/fixtures/encoding/generate_unmapped_glyphs.py index 8786b4a..f7ac346 100755 --- a/tests/fixtures/encoding/generate_unmapped_glyphs.py +++ b/tests/fixtures/encoding/generate_unmapped_glyphs.py @@ -72,8 +72,10 @@ def create_unmapped_glyph_pdf(output_path, glyphs, font_title="UnmappedTestFont" sorted_codes = sorted(glyphs.keys(), key=int) # Build the Differences array - differences = " ".join([f"{code} {glyphs[code]}" for code in sorted_codes]) + # Format: [starting_code glyph1 glyph2 glyph3 ...] + # The starting code establishes the base, then each glyph name maps to sequential codes first_code = sorted_codes[0] + differences = " ".join([glyphs[code] for code in sorted_codes]) # Object 1: Catalog obj1 = "1 0 obj\n<<\n/Type /Catalog\n/Pages 2 0 R\n>>\nendobj\n"