Prolens

A pro camera and photography toolkit for Android, built with Kotlin Multiplatform and Compose Multiplatform. The UI and logic are shared, so iOS can be added later as another target.

Download the latest APK from Releases, or see it on the website.

What's in it

• Viewfinder:
  • Capture modes in a strip above the shutter: Night, Micro, Macro, Photo, Slo-mo, Pano and Templates, each shown only when the phone can do it.
  • Lens chips from the phone's real zoom range, pinch to zoom, tap to focus and meter, press and hold to lock, and the front camera.
  • Live CameraX preview with 23 composition grids in six families (classic, golden ratio, triangles, diagonals, perspective and 3D, guides).
  • Level and camera-angle label, histogram, clipping warnings, focus peaking, zebras, false colour and waveform.
  • A lens frame for your real camera, the sun's path, and a 3D ground grid.
  • Manual ISO, shutter, white balance, EV and focus.
  • Aspect-ratio crops that are applied to the saved photo.
  • Camera-style rotation: the screen stays put and the icons turn with the phone.
• Calculators: depth of field, background blur, exposure, ND filter (with a timer), shutter speed, astro (500 and NPF rules), field of view, flash.
• Light: golden and blue hour for any place and date, in that place's time zone, plus the sun path, sun direction, shadow length and the moon.
• Coach: 15 genre recipes you can apply to the viewfinder, camera angles and shot sizes, lighting patterns, and composition principles.
• Gear: camera bodies and lenses, which every calculator and the lens frame use, and what this phone's cameras can do.
• Viewfinder settings, gear and location are saved between launches.

Project layout

androidApp/                      Android entry point (MainActivity, manifest)
shared/src/commonMain/.../prolens/
  app/                           AppState and the tab shell
  core/designsystem/             Theme (zinc, Geist), components, icons
  core/model/                    Gear, viewfinder settings, recipes
  core/photomath/                Exposure, depth of field, blur, FOV maths
  core/sun/                      Sun and moon positions and times (SunCalc port)
  core/grids/                    Grid geometry and Compose renderer
  core/platform/                 expect/actual seams: camera, sensors, permissions, location
  features/<screen>/             viewfinder, calculators, light, coach, gear
shared/src/androidMain/          CameraX + Camera2 interop, motion sensors, permissions
docs/RESEARCH.md                 The photography research and feature plan
docs/prototype/                  The HTML prototype (open index.html in a browser)

Build

You need JDK 21 and the Android SDK (local.properties with sdk.dir).

./gradlew :shared:testAndroidHostTest      # unit tests
./gradlew :androidApp:assembleDebug        # debug APK
./gradlew :androidApp:assembleRelease      # release APK

Release signing reads prolens.storeFile, prolens.storePassword, prolens.keyAlias and prolens.keyPassword from ~/.gradle/gradle.properties. Without them the release builds unsigned. Keystores and passwords are never committed.

Website

The landing page lives in website/ (React, Vite, TypeScript) and is published to GitHub Pages.

cd website
npm install
npm run dev      # local preview
npm test         # unit tests

Credits

• The sun and moon maths is ported from SunCalc by Vladimir Agafonkin (BSD-2-Clause).
• The Geist font is by Vercel (SIL Open Font License).

Licence

Copyright 2026 the Prolens contributors. Licensed under the Apache License 2.0.