Credits

Open-source software

Limcogito Toolbox is built on the work of many open-source projects. We are grateful to their authors and maintainers.

Only libraries under permissive licenses (MIT, Apache-2.0, BSD, ISC) are used. The one copyleft exception, libheif-js (LGPL-3.0), is credited below.

Libraries

Next.js and React power the site. next-intl provides the Vietnamese and English translations. Tailwind CSS provides the styling. The QR tool uses qrcode (MIT) to generate codes.

Image tools use jSquash codecs (mozjpeg, PNG, libwebp, libavif; Apache-2.0) and fflate (MIT). HEIC photos are decoded by libheif-js, licensed under the LGPL-3.0 and used unmodified: it is the one copyleft exception, loaded on demand as a separate file from /libheif/ together with its license text.

PDF tools use pdf-lib (MIT) to read, merge, split and rewrite files, pdf.js from Mozilla (Apache-2.0) to render pages for strong compression, and dnd-kit (MIT) for drag-and-drop reordering.

The lunar calendar tool computes new moons and solar terms from the formulas in Jean Meeus, "Astronomical Algorithms" (2nd ed., chapters 7, 25 and 49), with the Espenak and Meeus polynomials for the difference between dynamical and universal time published by NASA. It is implemented here in TypeScript for the Vietnamese rule (UTC+7).

The exercise data in the gym library (876 exercises with photos) comes from yuhonas/free-exercise-db, released under the Unlicense (public domain); photos are served from jsDelivr. The Vietnamese names and instructions are written by Limcogito Toolbox.

The gym tracker stores accounts and workouts in PocketBase (server, MIT) and talks to it through the PocketBase JavaScript SDK (MIT).