A lightweight, self-hosted PDF viewer with red/greenlining annotations, designed for viewing EPLAN schematics and similar technical PDFs directly in the browser.
The viewer runs fully client-side (no server needed) and can be hosted on GitHub Pages or any static web host.

• PDF.js v3 rendering — crisp, zoomable technical drawings
• Red/Greenlining tools:
  • Freehand pen (red or green)
  • Rectangles (red or green)
  • Inline text notes (gold)
• Pan & zoom for large drawings
• Undo / Clear / Save / Load
• Export / Import annotations as JSON
• Share links — annotations are embedded in the URL hash using LZ-String compression
  Anyone opening the link sees the same markup (no backend required)
• Local autosave — annotations are saved in localStorage when not using a shared link
• Offline-first — runs entirely in the browser, no login or internet connection needed

.
├── index.html          # Main viewer page
├── viewer.js           # Viewer logic (PDF rendering + annotations)
├── viewer.css          # Styling (black + gold theme)
├── docs/
│   └── project.pdf      # Example EPLAN PDF to view
└── assets/
    └── logo.png         # Optional logo

git clone https://github.com/AlbertjanPieffers/EKN_EplanViewer.git
cd EKN_EplanViewer

Put your EPLAN or other PDFs in docs/ and set PDF_URL in viewer.js:

const PDF_URL = "./docs/project.pdf";

Use any static HTTP server (not file:/// URLs).
For example with npx:

npx http-server .

Then open:

http://localhost:8080

1. Push your code to GitHub
2. Go to Settings → Pages
3. Under Build and deployment, set:
   • Source: Deploy from a branch
   • Branch: main / folder: / (root)
4. Save and wait a few seconds
5. Visit your site at:

https://<your-username>.github.io/<repo-name>/

• Click Share link — it copies a URL with #ann=... hash
• Send the link to anyone — they will see your red/greenlining
• If they edit, they must click Share link again to create a new link

Note: Shared links are read-only (they don’t overwrite local annotations).

MIT License — free for personal, educational, or commercial use.
Attribution is appreciated but not required.

• Add ellipse, arrow, or highlighter tools
• Allow switching between multiple PDFs
• Optional Supabase backend to sync annotations between users