Image / video labeling backend for the MoonbitLabeler app: 21 async ops over @fs/@json for folder browsing, image IO, label IO, schema normalization (parse/serialize round-trip), class management, and VOC/YOLO export. The op_handlers are pure async MoonBit functions and can be wired into any IPC layer (Proton/CEF, stdio JSON-RPC, HTTP, WASM, custom bridge). Includes a `dispatch_op(op, payload) -> Json raise` entry point in 0.2.0+ for embedding outside the CEF runtime.

labeling

image-annotation

voc

yolo

moonbit

ipc

json-rpc

Download zip

Author

riantr

Version

0.2.9

License

Apache-2.0

Repository

github.com/riantr/moonbit-labeler

Last updated

6 days ago

Downloads

Dependencies

#MoonBit Labeler

A native desktop image and video annotation tool for security X-ray scans, ported from a C# reference (MOlabeler_V2.6) to a MoonBit + Proton native stack (no Electron). Supports 4 annotation primitives (rectangle, polygon, keypoint, binding), custom JSON labels that round-trip both modern and legacy (CARS-dataset) schemas, and a 21-op IPC over ext:labeler/<op> that any host can drive.

For the full design doc see the project repo's README.md. For data format and project layout see that repo's README and docs/VIDEO_LABELING.md.

#Build from source

#Prerequisites

MoonBit ≥ 0.1.20260803 (the build host has moon 0.1.20260904)
Node.js ≥ 18 with npm on PATH (for the Vite frontend)
Proton CLI — proton_cli is the wrapper that drives the native AOT compile, downloads the CEF runtime, and assembles the exe. Install per https://github.com/moonbit-community/proton.
PowerShell 5.1 on PATH (Windows-only; the native folder picker spawns powershell.exe -NoProfile -NonInteractive -EncodedCommand)
~150 MB of disk for the first CEF download (proton_cli cef setup)

#One-time setup

# From the project root:
moon update                                          # sync moon.mod deps
proton_cli cef setup                                 # download CEF runtime into .proton/runtimes/
cd frontend && npm install && cd ..                 # install Vite + frontend deps (one-time per clone)

If frontend/node_modules/.bin/vite.cmd is missing, every subsequent proton_cli build step will fail with 'vite' is not recognized. Run the npm install line above to recover.

#Build the native executable

proton_cli build -- --release
# output: target/proton-dist/moonbit-labeler/moonbit-labeler.exe

--release is forwarded to the underlying moon build app invocation and turns on MoonBit's release-mode optimisations. Without it you get a debug build (~10× slower).

For a single-shot zip artifact too:

proton_cli package
# output: target/proton-dist/moonbit-labeler/moonbit-labeler.exe
#         target/proton-dist/moonbit-labeler/moonbit-labeler.zip (or use the wrapper _build/package-app.bat — see AGENTS.md)

_build/package-app.bat is a project-local wrapper that works around the upstream proton_cli@0.2.5 zip step bug (the staging directory is fully produced; only the auto-zip fails). It's gitignored (project-local tool) — recreate it from the snippet in AGENTS.md if missing.

#Verify a build

moon test --target native           # 38+1+1 = 40 unit + blackbox tests
node frontend/qa/webkit_picker_blackbox.test.mjs   # 6 frontend blackbox tests

#Run

# launch the packaged exe (it picks CEF mode if libcef.dll is present,
# --stdio mode if not — see _build/run.bat for the full wrapper):
_build/run.bat

# OR drive the labeler backend over JSON-RPC without launching CEF:
target/proton-dist/moonbit-labeler/moonbit-labeler.exe --stdio
# ...then send one JSON object per line on stdin, read responses on stdout.
# Wire format documented at the top of app/stdio_main.mbt and in the
# project README's "Stdio JSON-RPC bridge" section.

The exe is fully self-contained: drop target/proton-dist/moonbit-labeler/ on any Windows 10+ machine, double-click the exe. No installation required.

#Project layout (high-level)

.
├── app/                            # runnable entry (CEF + stdio)
├── extensions/labeler/             # 21 IPC ops + label/VOC/YOLO pipeline
├── frontend/                       # Vite + vanilla-JS UI (built into the exe at pack time)
├── moon.mod                        # declares deps: proton@0.2.5, proton_contract@0.2.5, moonbit_image@0.3.4
├── proton.project.json             # identifier, frontend, package (output dir, formats, version)
└── AGENTS.md                       # one-time setup + commands + smoke-test recipe (read first)

#Embedding the backend without CEF

The Moon-side handler set is pure async MoonBit and can be wired into any IPC layer. extensions/labeler/dispatch.mbt exposes a single entry point:

pub fn dispatch_op(op : String, payload : Json) -> Json raise

This is what app/stdio_main.mbt calls, and what you can call from your own host (Python Qt shell, Go service, embedded WASM, etc.). The 21 op names and their request/response JSON shapes are listed in extensions/labeler/extension.mbt and the project README.

#License

async_package_anchor

source

fn async_package_anchor() -> Bool raise

Anchor for moonbitlang/async. The async fn keyword alone is not counted as a use by the compiler (per moon 0.1.x), so we construct an Error via fail() and pass it to is_cancellation_error. The returned Bool is discarded; only the package reference matters.

fs_package_anchor

source

async fn fs_package_anchor() -> Bool

Anchor for moonbitlang/async/fs. kind is an async function returning FileKind; we probe a path that almost certainly does not exist and swallow any IO error — the goal is just to touch the @fs.* namespace.

image_package_anchor

source

fn image_package_anchor() -> Bool

Anchor for riantr/moonbit_image. Touches the cheapest function (detect_format on an empty byte buffer) so the image codec stays linked into the published artifact.

labeler_package_anchor

source

fn labeler_package_anchor() -> Bool

Anchor for riantr/moonbit_labeler/extensions/labeler. The dispatch_op_list() symbol is the cheapest entry into the labeler public API — no parameters, returns an Array[String]. We discard the array; only the package reference matters.