Argonaut

Minimalist document translator with a Qt (PyQt5) interface that uses argos-translate-files as an offline translation engine.

Two engines are available from Settings → Engine:

• Argos Translate (default) — light per-pair models, installed and removed from Settings → Manage language packages….
• NLLB-200 — Meta's nllb-200-distilled-600M (int8, CTranslate2), noticeably better quality and direct translation between any pair of 32 languages. The model (~630 MB) is downloaded on first use and stored under ~/.local/share/argonaut/. Note that the NLLB weights are licensed CC-BY-NC 4.0 (non-commercial).

Requirements

pip install PyQt5 argos-translate-lt argos-translate-files langdetect psutil

You need at least one language package installed. Open Settings → Manage language packages…, pick the pairs you want and press "Install selected"; the dialog lists every package from the Argos index with its version and download size, filters by installation state, and lets you remove or update the installed ones (a package with a newer version in the index is flagged and can be updated in place). They can also be installed from the command line with argospm install translate-en_es.

Usage

Install it (provides the argonaut command):

pip install argonaut-translator

From a checkout, install in editable mode first:

pip install -e .
python3 -m argonaut

Structure

All modules live in the src/argonaut/ package:

• __init__.py — package version (__version__).
• main.py — entry point; silences dependency warnings and launches the window.
• window.py — main window (PyQt5).
• worker.py — thread that translates the file list and emits progress signals.
• pdf.py — fixed PDF translator (paragraphs, progress, cancellation).
• translation.py — language detection, supported formats and the progress/cache wrapper.
• nllb.py — optional NLLB-200 backend (CTranslate2 + SentencePiece) exposing the same duck-typed API as argostranslate.
• packages.py — Argos package index, download, installation and removal.
• package_dialog.py — dialog to browse, install and remove packages.
• i18n.py — interface languages (English by default, Spanish, French, German, Italian and Portuguese).

Packaging lives at the top level: pyproject.toml (PyPI), io.github.nibblex.Argonaut.yml (Flatpak manifest) and data/ (desktop entry, AppStream metainfo and icon for Flathub).

Interface language

The interface starts in English. In the Language menu you can switch to Spanish, French, German, Italian or Portuguese; the change applies instantly and the preference is saved (QSettings) for future launches. To add a language just add its dictionary in i18n.py (missing keys fall back to English). The Help menu includes "About Argonaut", showing the version, a short description of the project, the translation engine, the supported formats, the author and the license.

Persistent settings

When the window closes, QSettings stores — besides the interface language — the source and target languages, the output folder and the window size/position; everything is restored on the next launch. If a saved language is no longer installed or the folder no longer exists, the default value is used. The active engine, the translation quality (Settings → Translation quality: best quality, or a faster greedy mode that trades a little accuracy for speed) and the number of CPU threads (Settings → CPU threads, defaulting to every detected core) are saved as soon as they change.

1. Choose the source and target languages (⇄ button to swap them). By default the source is "Detect language": each document's language is detected automatically, so you can mix files in different languages in the same batch.
2. Drag documents or whole folders onto the window (dropped folders are walked recursively) or add them with "Add…". Each file shows its size and the list footer shows the batch total.
3. Optionally pick a folder with "Output…" where all translations are saved (× returns to the default behaviour: next to each original). Tick "Skip files already translated" to leave existing outputs untouched, which makes an interrupted batch resumable.
4. Press "Translate". Each translated file is saved with the target language suffix (e.g. report_es.docx).
5. During translation you can press "Cancel": the operation stops (even mid-file) and the files already translated are kept.

Note about PDFs: they are translated paragraph by paragraph while preserving the layout, so a long document can take a while on CPU. The bar shows the real percentage of translated paragraphs and an estimate of the remaining time. Rotated text (e.g. vertical watermarks) is kept untranslated, and links from the original document are not preserved in the translated copy.

Supported formats: .txt .docx .odt .odp .pptx .epub .html .srt .pdf

Tests

pip install -e .[test]
pytest

The suite runs Qt headless (QT_QPA_PLATFORM=offscreen) and needs no language models: translation engines are faked. Coverage is printed at the end of the run; CI publishes the badge on every push to main.

Releasing

To publish a new version, bump __version__ in src/argonaut/__init__.py and add a <release> entry in data/*.metainfo.xml.

PyPI

pip install build twine
python3 -m build
twine upload dist/*

Flathub

The manifest is io.github.nibblex.Argonaut.yml. Flathub builds have no network access, so the Python dependencies must be pinned first with flatpak-pip-generator:

python3 flatpak-pip-generator --requirements-file=requirements.txt \
    --output python3-requirements

Test locally, then lint:

flatpak-builder --user --install --force-clean build-dir \
    io.github.nibblex.Argonaut.yml
flatpak run --command=flatpak-builder-lint org.flatpak.Builder \
    manifest io.github.nibblex.Argonaut.yml

First submission: take a screenshot for the metainfo (see the TODO in data/*.metainfo.xml), then open a PR against flathub/flathub (branch new-pr) adding the manifest, per the submission guide.

Author and license

© 2026 Sergio Rodríguez.

This project is distributed under the GNU GPL v3 license, in line with the license of PyQt5, which the interface depends on.