fix(export): render all diagrams in PDF and image output

[ThisIs-Developer]

What changed

• route vector PDF, raster PDF, and PNG exports through one off-screen rich-content renderer
• wait for Mermaid, ABC, PlantUML, D2, Graphviz, Vega-Lite, WaveDrom, Markmap, GeoJSON, TopoJSON, STL, math, fonts, and images before capture or print
• freeze exported Markmap SVGs to tight tree bounds so print output remains full-size and readable
• keep the chosen export theme scoped to the export snapshot so a dark export no longer turns the visible light app dark
• prevent light print-media rules from overriding dark frontmatter tables, Mermaid diagrams, remote diagrams, maps, and other rich content
• use a short, compact Appearance control while retaining the last choice for each export format
• keep browser and desktop resources synchronized

Why

The raster export paths only re-rendered Mermaid, ABC, and math, so the remaining diagram engines were captured as loading placeholders. Browser-print export also changed the application theme while preparing a differently themed PDF, and late light print rules caused white tables and diagrams inside dark PDFs. Markmap additionally reused its interactive viewport transform in print, shrinking trees to a few pixels inside a large SVG.

How it was tested

• npm test — 176 Chromium tests passed for the initial implementation
• npx playwright test tests/e2e/export.spec.js tests/e2e/markmap-export.spec.js --project=chromium — export coverage passed
• npx playwright test tests/e2e/rich-content.spec.js --project=chromium -g "renders Markmap" — live Markmap rendering passed
• added regression coverage that verifies every supported diagram renderer is present in vector PDF, raster PDF, and PNG captures
• added print-media coverage for dark tables, Mermaid colors, remote-diagram filters, app-shell hiding, and theme isolation
• added a real-library Markmap print test with basic, deep-hierarchy, and large-architecture trees; each must occupy a readable share of its fitted SVG
• visually checked the compact PDF Appearance control and live Markmap preview in the local app

Documentation

No public documentation changes are required; the export choices remain self-explanatory and continue to be remembered automatically.

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Project	Deployment	Actions	Updated
markdown-viwer	Ready	Preview	Sep 2, 2026 11:32am UTC