osign

Open, git-friendly design file format (built on JSON Canvas 1.0) plus a minimal viewer built with Kotlin Multiplatform + Compose Multiplatform. The viewer compiles to Kotlin/Wasm and runs in the browser. It's built with the Kotlin Toolchain (formerly Amper).

Layout

• project.yaml: Kotlin Toolchain project config (module list)
• common.module-template.yaml / compose.module-template.yaml: shared Kotlin and Compose settings
• libs.versions.toml: project library catalog ($libs.* dependencies)
• kotlin / kotlin.bat: Kotlin Toolchain wrapper scripts (pin the toolchain version)
• shared/: KMP library with osign models, parseOsign, and basic validation (src/ code, test/ tests)
• shared-ui/: Compose Multiplatform UI (file picking, canvas rendering with pan/zoom, inspector)
• web-app/: Kotlin/Wasm entry point (src/main.kt) and its resources/index.html
• build-web.sh: builds the web app and stages it in web-app-dist/ as a static site
• icons/icon-source.png: source artwork for the app icon (web-app/resources/favicon.png)
• docs/: spec docs (osign-overview.md, osign-file-format.md)
• schema/osign.schema.json: minimal JSON Schema for basic shape validation
• examples/hello-world.osign.json: desktop marketing hero sample
• examples/mobile-app.osign.json: mobile app mock paired with assets under examples/resources/mobile/

Prerequisites

• A JDK isn't needed up front: ./kotlin provisions its own.
• just for the recipes below.

Common tasks

just build      # compile every module
just test       # run unit tests
just web        # serve the viewer at http://127.0.0.1:8080

Run just to list every recipe.

Using the viewer

Click Open files and select an .osign.json document, or drag and drop it onto the window. The browser can't read files from disk by path, so select any local images the document references (for example examples/mobile-app.osign.json together with examples/resources/mobile/*.png) in the same dialog (or drop). Relative asset paths are matched by file name. Assets given as data: URIs or http(s) URLs load without extra files.

Web viewer on GitHub Pages

.github/workflows/pages.yml tests, builds the release web app, and deploys web-app-dist/ to GitHub Pages on every push to main. To turn it on, set Settings → Pages → Source to GitHub Actions.

Testing notes

The Kotlin Toolchain can't run Kotlin/Wasm tests yet (KTC-5576), so shared also targets the JVM, and that's where its unit tests run.

Updating the toolchain

./kotlin update

Docs

• docs/osign-overview.md
• docs/osign-file-format.md
• Schema: schema/osign.schema.json
• Sample: examples/hello-world.osign.json

License

osign (the specification, schema, and code) is released under the MIT License.

osign builds on JSON Canvas, an open format created by Obsidian and also published under the MIT License.