The fastest, most private,
most beautiful PDF studio.

Everything inside

One extension. Four studios. Zero paywalls. The full printable catalogue lives in docs/FEATURES.md. The manual lives in docs/USER_GUIDE.md.

How it works

Same Mermaid diagrams as the README. Copy any block into a Markdown viewer to re-render it.

Browser
  popup (toggles) --message--> background worker --redirect--> viewer tab
  viewer --uses--> vendor (pdf.js, pdf-lib, qpdf, cmaps)
  viewer --uses--> nevaipdf-ops (merge/split/rotate/watermark)
  viewer <--> IndexedDB (recents + annots)
  viewer + popup <--> chrome.storage.local (prefs)

Open (file/drop/URL/recent)
  -> docIdFor(name+size+hash) -> getDocument -> metadata
  -> baseSizes (page 1 fast, rest chunked) -> buildPages + observer
  -> visible? --yes--> renderPage: canvas + textLayer + linkLayer
  -> highlight + annot overlay -> rendered

Your PDF --> stays on device (blob: URL) --> renders in page
  --> recents + annots in IndexedDB (local only)
Your PDF - - NEVER - -> Internet

More diagrams (folder map, lifecycle, annotation engine, search engine, edit engine, responsive breakpoints) are in the README and docs/architecture.md.

Under the hood

Engineering notes for contributors: the resilience rules, the storage contract and the performance budget that keep it instant on 1000-page files.

error -> type
  stale epoch        -> abort + retryRender once
  render cancelled   -> treat as normal, re-queue
  wrong password     -> unlock modal re-prompts
  CORS on URL fetch  -> hint: download then drag and drop
  file:// blocked    -> hint: enable file URLs permission
  missing vendor     -> fatal banner naming the file
  runtime error      -> global handler -> toast with the real message

open document      -> recents + last page (IndexedDB)
draw or erase mark -> stroke JSON (IndexedDB, pruned to 60 docs)
settings/profile   -> prefs (localStorage)
tools tab actions  -> stopwatch / counters / tracker / todos (localStorage)
Hub -> Backup      => one JSON (format v4)
Hub -> Restore     => re-import (additive, version-tolerant)

Deep dive: docs/architecture.md · docs/API.md · docs/TESTING.md

Documentation library

Nine pages plus the README. Everything is plain Markdown, printable, and emoji-free by policy (CI enforces it).

Roadmap

Shipped, in progress and planned. Vote with a thumbs-up on the feature request to move a version up.

Release process, versioning rules and the timeline diagram live in docs/ROADMAP.md. Release notes template: .github/RELEASE_TEMPLATE.md.

How it looks

Real captures from the app (mock previews — replace the files in docs/screenshots/ with your own 1:1 anytime). The README shows the same images.

Light mode

Dark mode

Sidebar studios

Annotate Studio

Edit Studio

Mobile 360px

Install in 30 seconds

Works in Chrome, Vivaldi, Yandex Browser, Edge, Brave, Opera and Arc — any Chromium. Illustrated guide: docs/INSTALLATION.md.

git clone https://github.com/Ahmedbakr78/Heros_PDF.git
cd Heros_PDF
# your-extensions-page → Developer mode ON → Load unpacked → pdf-studio-extension/
# Details → Allow access to file URLs  (for file:// auto-open)
# Optional local preview (no install):
cd pdf-studio-extension && python3 -m http.server 8000
# → http://localhost:8000/viewer.html

Shortcuts

Full list is also in-app: More → Keyboard shortcuts. Full manual: USER_GUIDE.md.

Why Heros wins

Built-in viewers show pages. Web tools charge you. Heros does everything, locally, free.

Topics and About

Copy-paste source: .github/GITHUB_META.md. No emojis anywhere.

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