LensApp/README.md

LensApp

A small React Native document scanner. Point it at a page, it crops the edges, lets you review, and saves a PDF you can share.

Built on top of react-native-document-scanner-plugin, with react-native-html-to-pdf for export and react-native-share for sending things out.

What's in it

• Scan multi-page documents with automatic edge detection
• Review pages before saving (reorder, retake, apply a filter)
• Persist scans locally, rename them, view them later
• Export as PDF and share

Screens live in src/screens/ — Home, Scan, Review, Viewer. Navigation is plain state in App.tsx; there's no router dependency. Document storage is a simple hook (src/hooks/useDocumentStore.ts).

Requirements

• Node 18+
• JDK 17, Android SDK (for Android)
• Xcode + CocoaPods (for iOS)

The usual React Native 0.73 setup. If you haven't done this before, the RN environment guide is the canonical reference.

Running it

Install:

npm install

iOS only — install pods:

cd ios && pod install && cd ..

Start Metro in one terminal:

npm start

Then in another:

npm run android
# or
npm run ios

Tests

Unit tests (Jest + React Native Testing Library):

npm test

Builds

Android release APKs are split per-ABI (armeabi-v7a, arm64-v8a, x86_64) — see android/app/build.gradle. Per-arch APKs are smaller than a universal one.

CI builds live in .github/workflows/.

Project layout

App.tsx                # screen switcher + top-level state
src/
  screens/             # Home, Scan, Review, Viewer
  components/          # DocumentCard, FilterPicker
  hooks/               # useDocumentStore
  utils/               # generatePdf, imageProcessing
  types/               # shared types
patches/               # patch-package patches applied postinstall

Notes

• Alert.prompt is iOS-only; the rename flow falls back to a modal on Android (see App.tsx).
• postinstall runs patch-package — if a patch fails to apply after a dependency bump, check patches/.