feca-mailshots-plugin/results/dompdf_investigation_findings_2026-04-20.md

dompdf Investigation Findings (2026-04-20)

Scope

Investigation run against:

• samples/renewal_draft.html
• samples/invoicing.html

Using spike script:

• working/codex-spikes/dompdf_spike.php

Execution Summary

• dompdf installed via Composer: dompdf/dompdf v3.1.5.
• Spike rendered both templates to PDF successfully (exit code 0).
• Output PDF metadata confirms:
  • producer dompdf 3.1.5 + CPDF
  • Pages: 1
  • A4 page size for both files.

Generated artefacts:

• working/dompdf/rendered_html/renewal_draft.rendered.html
• working/dompdf/rendered_html/invoicing.rendered.html
• working/dompdf/pdfs/renewal_draft.pdf
• working/dompdf/pdfs/invoicing.pdf

Objective Checks

1. Render success

   • Result: PASS
   • Evidence: spike script completed and wrote both PDFs.

2. Unicode/currency symbols in invoicing output

   • Result: PARTIAL
   • Evidence:
     • £ extracted correctly from PDF text.
     • ✉ extracted correctly from PDF text.
     • phone symbol 📞 extracted as replacement glyphs (<EFBFBD><EFBFBD>) in text extraction.
   • Interpretation: likely font/glyph coverage issue for this symbol.

3. Renewal draft watermark and complex layout

   • Result: PARTIAL
   • Evidence:
     • watermark text appears in extracted PDF text stream as split/reordered letters, indicating transformed/fixed-position content was processed.
   • Interpretation: confirms render path handled transformed watermark content, but fidelity must be visually verified.

4. Tables/spacing/mm layout constraints

   • Result: NOT YET VERIFIED
   • Evidence: no browser baseline comparison completed in this run.

Recorded File Fingerprints

• working/dompdf/pdfs/invoicing.pdf
  • sha256: 881ce70e95621423c7b0629e777190ee6c6e64079103e7c81ae18f46bbf5111a
• working/dompdf/pdfs/renewal_draft.pdf
  • sha256: a92e64b4ebe7553068163f07d108d1cfadfd8955f1ec4940811dfafd540a73e7
• working/dompdf/rendered_html/invoicing.rendered.html
  • sha256: 9f5182485e21e979cf9b0eb1ed0500381a62d3d9269e5a2d19f080f4a8a34a1c
• working/dompdf/rendered_html/renewal_draft.rendered.html
  • sha256: b81b8fea7f07bcdf32667adc27f88cc060c1d7a1c741fbacd87b494bff2568e9

Current Suitability Status

Provisional outcome: Suitable with constraints (pending visual baseline comparison).

Rationale:

• Core render pipeline works for both templates.
• At least one symbol (📞) shows a likely glyph-support problem.
• Watermark/transformed layout needs visual pass/fail against browser print baseline before final sign-off.

Stakeholder Visual Review Outcome

Review date: 2026-04-20.

Outcome recorded from user review:

• Visual output is acceptable for current templates, excluding missing production mailshot assets in this spike context.
• Non-appearing special characters are acceptable for now.

Decision update:

• Suitability status is now Accepted: suitable with constraints.

Constraints / Risks Identified

1. Emoji/supplementary symbols may not render reliably with default font setup.
2. CSS transform/fixed-position behavior is active but not yet visually validated for final layout fidelity.

Required Next Validation

1. Generate browser print-to-PDF baseline for both sample templates.
2. Perform side-by-side visual check for:
   • watermark position/opacity/rotation
   • table borders and spacing
   • line wrapping and paragraph flow
   • logo placement
3. Decide whether to:
   • accept template constraints (for unsupported symbols), or
   • change fonts/renderer strategy.

Rerun Record (Corrected invoicing template)

Rerun timestamp: 2026-04-20 14:05:44 BST.

Reason:

• samples/invoicing.html was corrected after the initial run (original sample was malformed).

Updated artefact fingerprints:

• working/dompdf/pdfs/invoicing.pdf
  • sha256: ef5f12648cd29fde01398efe81e4873ce70b273fe3587d3de56596740af6c765
• working/dompdf/pdfs/renewal_draft.pdf
  • sha256: b2d2babc4f6918db8067f02b9a81ca4d7eb0e9e25bbda8223b59ae0d433b869f
• working/dompdf/rendered_html/invoicing.rendered.html
  • sha256: 2536cbc2eecfa6eb09ddc2c1832e2c2b8ae98200f42f31537182d3baf555845c
• working/dompdf/rendered_html/renewal_draft.rendered.html
  • sha256: b81b8fea7f07bcdf32667adc27f88cc060c1d7a1c741fbacd87b494bff2568e9