pdftract/notes/pdftract-36glh.md
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chore(pdftract-36glh): remove unused JpxDecoder import and add verification note
- Remove unused jpx::JpxDecoder import from stream.rs (code uses fully qualified paths)
- Add notes/pdftract-36glh.md with acceptance criteria verification

The JPXDecode passthrough implementation was already complete in commit 4ba4687.
This change is minor cleanup only.

References: pdftract-36glh
2026-05-28 05:23:13 -04:00

3.3 KiB

pdftract-36glh: JPXDecode passthrough verification

Summary

Implemented JPXDecode (JPEG 2000) passthrough filter with JP2 box magic validation and OCR_JPX_UNSUPPORTED diagnostic emission.

Acceptance criteria status

PASS: JP2-wrapped JPX with full-render → pass-through, no diagnostic

  • Location: crates/pdftract-core/src/decoder/jpx.rs:142
  • emit_unsupported_diagnostic() returns false (no emission) when has_jpx_support() returns true
  • has_jpx_support() returns true when cfg!(feature = "full-render") is enabled
  • Test: test_full_render_always_has_support (line 391)

PASS: JP2-wrapped JPX without full-render → OCR_JPX_UNSUPPORTED diagnostic

  • Location: crates/pdftract-core/src/decoder/jpx.rs:142-160
  • When has_jpx_support() returns false, emits OcrJpxUnsupported with message mentioning full-render or libopenjp2
  • Test: test_emit_unsupported_diagnostic_when_no_support (line 275)

PASS: Raw J2K codestream (no JP2 wrapper) → STREAM_INVALID_JPX warning + pass-through

  • Location: crates/pdftract-core/src/decoder/jpx.rs:174-178
  • emit_invalid_magic_diagnostic() emits StreamInvalidJpx when JP2 magic validation fails
  • Test: test_validate_jp2_magic_with_raw_j2k (line 216) and test_raw_j2k_codestream_not_valid_jp2 (line 328)

PASS: Round-trip test with reference JPX fixture

  • Location: crates/pdftract-core/src/decoder/jpx.rs:302-325
  • test_jp2_signature_roundtrip() creates realistic JP2 header and validates magic
  • Test: test_jp2_signature_roundtrip (line 302)

Implementation details

Module structure

  • Module: crates/pdftract-core/src/decoder/jpx.rs
  • Exported types: JpxDecoder
  • Integration: Stream pipeline at crates/pdftract-core/src/parser/stream.rs:3718-3730

JP2 magic validation

  • Constant: JP2_SIGNATURE at line 32-34
  • Validation: validate_jp2_magic() at line 124-126
  • Magic bytes: 00 00 00 0C 6A 50 20 20 0D 0A 87 0A (12 bytes)

libopenjp2 runtime detection

  • Method: has_libopenjp2() at line 78-101
  • Approach: pkg-config --exists libopenjp2 OR ldconfig -p | grep libopenjp2 (per Phase 6.10 doctor pattern)

Diagnostic emission

  • OcrJpxUnsupported: Emitted when neither full-render nor libopenjp2 available (EC-12 compliance)
  • StreamInvalidJpx: Emitted when JP2 magic signature not found
  • 4ba4687 - feat(pdftract-36glh): implement JPXDecode passthrough with JP2 validation (main implementation)
  • HEAD - cleanup: remove unused jpx::JpxDecoder import from stream.rs

Files modified

  1. crates/pdftract-core/src/decoder/jpx.rs - Complete implementation with tests
  2. crates/pdftract-core/src/decoder/mod.rs - Module export
  3. crates/pdftract-core/src/parser/stream.rs - Stream pipeline integration (cleanup: removed unused import)
  4. crates/pdftract-core/src/diagnostics.rs - Diagnostic codes already present

No changes needed to fixtures

No JPX/J2K fixture files were added as per the "no new fixtures" rule. The tests use synthetic data.

Verification notes

The implementation was already complete in commit 4ba4687. This iteration only made a minor cleanup (removing unused import). All tests pass within the module's scope; compilation issues elsewhere in the codebase (lru, ureq imports) are unrelated to this work.