StickerFit

StickerFit is a Windows-first Tauri desktop app for turning local media into a Discord-compatible APNG sticker.

Current scope

• Desktop app first: the Tauri build performs inspection, optimization, export, and output-folder actions locally.
• Web preview mode: the browser build is for layout and interaction verification only.
  • Supported in web mode: file inspection, crop, zoom, timeline review, and overlay flows.
  • Not supported in web mode: optimization search, PNG export, and output-folder actions.
• Target output constraints:
  • 320x320 max dimensions
  • <= 512 KiB
  • <= 5 seconds

Supported inputs

• Video or animated sources: mp4, gif, webm, mov, m4v, apng
• Still images: png, jpg, jpeg, bmp

What it does

• Inspects local media with bundled ffmpeg plus native Rust parsers for still images, GIF, and APNG
• Builds a ranked candidate ladder for Discord-safe APNG output
• Chooses the best result by preferring candidates that stay closest to the source while still fitting the Discord limit
• Supports crop selection, zoom, frame review, and frame editing before export
• Converts supported still images to PNG with the current crop applied and with output capped to Discord size limits
• Lets users choose an output folder, or defaults to the source file folder
• Starts in Korean on Korean systems and English otherwise

Static image vs animated/video flow

• Still images:
  • Show crop and zoom controls
  • Offer direct PNG conversion
  • Do not show frame-rate or timeline transport UI
• Animated/video sources:
  • Show frame rail, playback/timeline, preview candidates, and optimizer results
  • Use ranked search to find the best APNG output under Discord limits

Tech stack

• Frontend: React + TypeScript + Vite
• Desktop shell: Tauri v2
• Media tooling: bundled ffmpeg sidecar
• Backend layer: Rust commands exposed through Tauri
• Test tooling: Vitest for pure frontend logic, Playwright for web smoke checks

Project layout

• src/ - React UI, workflow logic, and frontend tests
• src-tauri/ - Rust backend, Tauri config, bundled binaries, and backend tests
• tests/ - Playwright web smoke checks
• docs/ - beta checklist and supporting notes

Development

Requirements:

• Node.js 20+
• Rust stable toolchain
• Microsoft C++ Build Tools on Windows (Desktop development with C++)
• WebView2 runtime on Windows
• Microsoft Edge installed for npm run test:web-smoke

Notes for Windows:

• These prerequisites apply to developers building the Tauri shell locally.
• End users running a prebuilt StickerFit app do not need Node.js, Rust, or Visual Studio Build Tools.
• StickerFit uses Tauri's default Windows MSVC toolchain path.

For a clean-machine bootstrap on Windows, run the repository entrypoint below from an elevated PowerShell window. It installs the required toolchain with winget, ensures the MSYS2 packages needed for the minimal ffmpeg sidecar build, builds the sidecar, runs npm ci, and produces the desktop bundles.

powershell -ExecutionPolicy Bypass -File .\tools\bootstrap-build-windows.ps1

Optional flags:

• -Clean: remove dist/ and src-tauri/target/release/ before rebuilding
• -RunChecks: run unit, Rust, and web smoke tests after the desktop build
• -SkipDependencyInstall: use the current machine state as-is and only run the build steps

npm install
npm run dev:desktop

For browser-only preview work:

npm run dev:web

Build

npm run build:web
npm run build:desktop -- --no-bundle

For the full clean-machine bootstrap from inside the repo after Node is already available:

npm run bootstrap:windows

For a debug desktop build:

npm run tauri build -- --debug --no-bundle

Verification

npm run test:unit
npm run test:rust
npm run test:web-smoke

For the current beta verification bundle:

npm run check:beta

Notes

• Output files are saved next to the source file unless the user chooses another folder.
• The desktop app requires the bundled ffmpeg sidecar for desktop processing and does not fall back to system tools.
• The current beta release checklist is in docs/beta-release-checklist.md.