[Layout fidelity] Cumulative pagination drift vs Word/PDF in DC template (section/table spacing and page break mismatch)

[leandrotcawork]

Summary

When rendering the DC template DOCX in SuperDoc (Layout Engine ON), pagination drifts cumulatively compared to Word/PDF.
This is not an isolated section-05 bug; vertical drift appears earlier and accumulates until page boundaries diverge.

Impact

This is a source-of-truth fidelity issue for enterprise/legal documents where section starts and page boundaries must match Word/PDF output.

Fixture

• Document: DC_Template_Descricao_Cargo.docx
• Baseline: Word export / PDF of same DOCX
• SuperDoc mode: Layout Engine ON (DomPainter visible output)

Observed mismatch

• In Word/PDF, section 05 continues on page 3.
• In SuperDoc, section 05 is fully consumed on page 2, and page 3 starts at section 06.
• Drift continues in later pages (section/page starts do not align with Word/PDF).

Repro steps

1. Open DC_Template_Descricao_Cargo.docx in SuperDoc with Layout Engine ON.
2. Compare pages 2-4 with Word/PDF export of the same DOCX.
3. Observe that post-table spacing and section start positions are higher in SuperDoc than Word/PDF.
4. Observe page-break divergence (notably around sections 05/06 and later sections).

Expected

SuperDoc page composition (section starts, table-to-heading spacing, page breaks) should match Word/PDF for this fixture.

Actual

SuperDoc produces less vertical consumption across repeated sections/tables, causing cumulative upward drift and earlier section starts.

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What we investigated

1) Renderer/path ownership

• Confirmed with Layout Engine ON that visible output is DomPainter path.
• Drift is present in layout snapshot data before final paint, so this is not only a paint-layer issue.

2) Whole-document behavior

• Section 05 was initially used as a visible example, but analysis of the whole document shows cumulative drift from earlier sections.
• Repeated sections with similar table structures show repeated interval under-spacing.

3) Structural evidence

• Rows/cells are present; this is not a missing table rows ingestion issue.
• The issue behaves like vertical measurement/accounting mismatch rather than dropped content.

4) OOXML signal identified

• Fixture contains w:docGrid w:linePitch="360" (24px at 96dpi).
• Hypothesis: Word grid-aware vertical behavior is not fully reflected end-to-end in SuperDoc measurement/layout for this scenario.

5) Attempted fix branch status

• A local PR investigation branch attempted constrained propagation/measurement changes.
• Visual parity was still not fully achieved end-to-end.
• I intentionally did not keep this as an upstream PR candidate.

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Artifacts / archive

Screenshot package (Word vs SuperDoc)

• Individual files:
• Superdoc:

- Word:

DC_Template_Descricao_Cargo.docx

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Environment

• OS: Windows
• Local validation date: May 13, 2026
• Rendering mode: Layout Engine ON

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Request

Please triage as a layout-fidelity bug (Word/PDF parity) with emphasis on cumulative vertical accounting across repeated table/section structures, not only the section-05 boundary symptom.

[linear]

IT-1048