ouestcharlie-imageproc

Image processing coprocessor for OuEstCharlie — a Rust CLI (image-proc) bundled with a Python subprocess wrapper.

Handles all pixel-level operations: decoding, EXIF orientation, resize, fit, and encoding to AVIF or JPEG. Used by ouestcharlie-py-toolkit for thumbnail grid assembly and on-demand preview generation.

What's in this package

• image-proc — Rust CLI that reads JSON requests from stdin and writes JSON responses to stdout (newline-delimited, persistent coprocessor model).
• ouestcharlie_imageproc.image_proc — Python subprocess wrappers: OneTimeImageProc (fresh process per request) and PersistentImageProc (long-lived process with asyncio lock).

Supported formats

Building

Requires Rust stable, nasm, and (for HEIC) libheif:

# macOS
brew install nasm inih libheif

# Linux
sudo apt-get install nasm libheif-dev

# Windows
choco install nasm
# libheif via vcpkg — see .github/workflows/_build.yml for the bootstrap steps

# Install as editable (development)
pip install -e . --no-build-isolation

# Build release wheel
IMAGE_PROC_FEATURE_RAW=1 IMAGE_PROC_FEATURE_HEIC=1 hatch build --target wheel

Published wheels set both IMAGE_PROC_FEATURE_RAW and IMAGE_PROC_FEATURE_HEIC via CI — a bare pip install -e . or hatch build without the env vars excludes both, same as cargo build without --features.

Running tests

# Unit tests (no binary required)
.venv/bin/python -m pytest tests/ -v

# Integration tests (require compiled binary)
.venv/bin/python -m pytest tests_integration/ -v

# Rust tests
cd image-proc && cargo test

Design

See imageproc_LLD.md for the protocol specification, command reference, and build details.