LumaFace — Photo Editor with Filters & Stickers

Inspiration

Modern mobile photo editors are bloated with ads, tracking, or mandatory cloud uploads. We wanted a privacy‑first tool that stays laser‑focused on editing. LumaFace proves that pro‑grade results and absolute on‑device privacy can coexist in a lightweight package.

What it does

End‑to‑end on‑device editing — never leaves your phone.
Filters & Looks — vintage film, cinematic tones, crisp B/W, modern palettes.
Advanced Color Control — exposure, contrast, warmth, saturation, shadows, highlights.
Text on Photos — custom fonts, layouts, captions, headlines.
Sticker Packs — curated from minimal accents to playful graphics.
Crop & Format Tools — presets for Instagram, TikTok, Threads, slides, or custom ratios.
Clean Workflow — open, edit, and export in seconds without clutter.

How we built it

SwiftUI + Combine for a reactive UI.
Core Image pipelines & Metal Performance Shaders for real‑time previews.
Custom LUT engine for film‑style filters.
RevenueCat for subscription management.
Swift Package Manager to modularize filters, fonts, and stickers.
XCTest & SnapshotTesting for unit and UI tests.

Challenges we ran into

Performance vs. quality — instant previews without sacrificing fidelity.
Memory constraints on older devices during high‑res edits.
Non‑destructive workflow — building an editable history stack.

Accomplishments that we're proud of

100 % on‑device processing validated by privacy audit tools.
TestFlight build with a 95 % user‑satisfaction rating.
96 % code coverage across core modules.
Extensible sticker ecosystem with dynamic loading.

What we learned

UX minimalism pays off — fewer buttons ⇒ faster adoption.
Local processing builds trust; beta testers cited privacy as the #1 retention driver.
Automated tests halved debug time during the sprint.
RevenueCat simplifies subs but still needs edge‑case handling.