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romulocrj
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Aug 6, 2026
romulocrj
commented
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- Updated JPEG parsing logic to recognize and accept progressive JPEG metadata.
- Changed variable names for clarity, replacing 'foundBaseline' with 'foundFrame'.
- Enhanced error messages for unsupported frame markers and component data.
- Adjusted tests to validate progressive JPEG handling and ensure proper rejection of unsupported formats.
…mprove error handling - Updated JPEG parsing logic to recognize and accept progressive JPEG metadata. - Changed variable names for clarity, replacing 'foundBaseline' with 'foundFrame'. - Enhanced error messages for unsupported frame markers and component data. - Adjusted tests to validate progressive JPEG handling and ensure proper rejection of unsupported formats.
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Pull request overview
Refactors the JPEG metadata parser so the library can embed more JPEG variants (notably progressive) by recognizing additional SOF frame markers, and updates tests/docs/examples accordingly.
Changes:
- Extend
parseJpegto accept DCT-based SOF markers (SOF0/SOF1/SOF2) and improve unsupported-frame error messaging. - Add/adjust tests and examples to exercise progressive JPEG handling and updated error expectations.
- Update roadmap/porting status documentation and regenerate distribution/type artifacts.
Reviewed changes
Copilot reviewed 6 out of 9 changed files in this pull request and generated 2 comments.
Show a summary per file
| File | Description |
|---|---|
| test/jpeg_phase_4_2.test.mjs | Adds progressive JPEG fixture coverage and updates rejection expectations. |
| src/pdf/image/jpeg.ts | Expands accepted SOF markers to include progressive/extended sequential and updates error handling. |
| examples/jpeg-phase-4.2.mjs | Updates the phase 4.2 demo to render baseline/extended/progressive JPEG cards. |
| examples/generation-results.json | Updates generation timestamp metadata. |
| docs/ROADMAP.md | Updates phase 4.2 description to reflect progressive support. |
| docs/PORTING-STATUS.md | Updates porting status text for JPEG parsing scope. |
| dist/types/pdf/image/jpeg.d.ts | Updates public typings docstring to match new JPEG scope. |
| dist/js_pdf.mjs | Regenerated bundle reflecting updated JPEG parsing logic. |
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| function replaceFrameMarker(bytes, from, to) { | ||
| const copy = bytes.slice(); | ||
| for (let index = 2; index + 1 < copy.length; index++) { | ||
| if (copy[index] === 0xff && copy[index + 1] === from) { | ||
| copy[index + 1] = to; | ||
| return copy; | ||
| } | ||
| } | ||
| throw new RangeError(`JPEG frame marker 0x${from.toString(16)} was not found`); | ||
| } |
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| test('parseJpeg accepts progressive JPEG metadata', () => { | ||
| assert.deepEqual(Pdf.parseJpeg(PROGRESSIVE), { | ||
| width: 2, | ||
| height: 2, | ||
| bitsPerComponent: 8, | ||
| components: 3, | ||
| colorSpace: 'rgb', | ||
| inverted: false | ||
| }); | ||
| }); | ||
|
|
||
| test('parseJpeg rejects unsupported frames, truncated data and unsupported components', () => { | ||
| assert.throws(() => Pdf.parseJpeg(jpeg(sof(0xc3, 10, 10, 3))), /frame marker/); | ||
| assert.throws(() => Pdf.parseJpeg(Uint8Array.from([0xff, 0xd8, 0xff, 0xe0, 0, 20])), /truncated/i); | ||
| assert.throws(() => Pdf.parseJpeg(jpeg(sof(0xc0, 10, 10, 2))), /component/); | ||
| }); |
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