# gud.pics — source, licenses, and changes

Independent browser prototype. Not affiliated with or endorsed by darktable or Adobe.

## Source provenance

Vendored darktable revision: `0286264e169eec79ce8d3744d6e477dcb18d9d94`.
Repository: https://github.com/darktable-org/darktable

- `native/upstream/ashift.c`: darktable developers, GPL-3.0-or-later.
- `native/upstream/ashift_lsd.c`: darktable integration, GPL-3.0-or-later; embedded LSD 1.6 by Rafael Grompone von Gioi et al., AGPL-3.0-or-later.
- `native/upstream/ashift_nmsimplex.c`: darktable integration, GPL-3.0-or-later; embedded Nelder–Mead implementation by Michael F. Hutt, MIT-style permission notice retained in full.
- Emscripten-generated runtime: Emscripten authors, MIT / University of Illinois/NCSA; see `LICENSES/EMSCRIPTEN.txt`.
- New adapter, browser code, crop algorithm, and build scripts: AGPL-3.0-or-later. Provided without warranty.

Original notices are retained in the source. Both GPL and AGPL license texts are supplied. GPLv3 §13 and AGPLv3 §13 address their combination. The public repository at https://github.com/FelineStateMachine/gudpics contains the preferred editable forms and build instructions; keep it available when distributing this combined work. No paid or proprietary assets are used.

## Fuji tool

- LibRaw (https://github.com/LibRaw/LibRaw), revision `116924e5bcb9483ef9c5fbe7f3cfc5a8a4b97064`, unmodified, compiled to WebAssembly with the thin wrapper in `native/raw/wrapper.cpp`. LibRaw is used under the LGPL-2.1; see `LICENSES/LGPL-2.1.txt` and `LICENSES/LIBRAW-COPYRIGHT.txt`. Obtain its source at the URL above at the pinned revision.
- Film simulation LUTs in `assets/luts/` (provia, velvia, astia, classic_chrome, pro_neg_std, pro_neg_high, eterna, acros, mono and filter variants, sepia): Bastian Bechtold, https://github.com/bastibe/Fujifilm-Auto-Settings-for-Darktable revision `79a458ce9bc28c870091c978b829aaed8dbdb45a`, GPL, unmodified. They were fitted from a Fujifilm camera's own renders against darktable's default render and approximate the camera looks.
- `lens.mjs`: Fujifilm in-camera lens correction (distortion, chromatic aberration, vignetting) from the RAF metadata splines. Algorithm adapted from darktable 4.6 `src/iop/lens.cc` and RawTherapee `rtengine/lensmetadata.cc`, both GPL-3.0-or-later.
- `assets/luts/neutral-dr*.png`: generated by `scripts/neutral-lut.py` using darktable-cli 5.6.1 (GPL-3.0-or-later). They map LibRaw's render to darktable's default scene-referred render so the film simulation LUTs apply as intended. Film simulation names are Fujifilm trademarks used to identify the looks being approximated; this project is not affiliated with Fujifilm.

- Interface glyphs on the landing page and empty states: Lucide Icons (https://lucide.dev), ISC license, see `LICENSES/LUCIDE.txt`.

## Extraction changes (2026-09-21)

`scripts/extract.py` reproducibly selects darktable's original constants, line classification, vector helpers, homography, RANSAC, model fitness and Nelder–Mead fit from the pinned source. It uses the original LSD detector and simplex implementation.

Changes: remove GTK, image pipeline and OpenMP dependencies; supply portable math helpers; keep minimal fit state behind a C API; accept display-referred RGBA rather than RAW; omit the optional detail and edge enhancement preprocessing; replace darktable logging in LSD with stderr. Keep one/two-line selections when RANSAC is skipped. Seed RANSAC deterministically. Add input and finite-result checks at the browser boundary. The generic 28 mm lens model is used, without EXIF focal-length inference.

Browser preview/export uses a new inverse-mapped bilinear renderer. Automatic crop uses a new conservative polygon scan; it does not reproduce darktable's crop optimizer. Analysis is limited to 960 pixels on the long edge; export to 2560 pixels and 4 megapixels. The browser supplies decoding, orientation, and canvas color conversion. Results are not claimed to be pixel-identical to darktable or Lightroom.

## Source references

- Module: https://github.com/darktable-org/darktable/blob/0286264e169eec79ce8d3744d6e477dcb18d9d94/src/iop/ashift.c
- Detector: https://github.com/darktable-org/darktable/blob/0286264e169eec79ce8d3744d6e477dcb18d9d94/src/iop/ashift_lsd.c
- Optimizer: https://github.com/darktable-org/darktable/blob/0286264e169eec79ce8d3744d6e477dcb18d9d94/src/iop/ashift_nmsimplex.c
- Manual: https://darktable-org.github.io/dtdocs/en/module-reference/processing-modules/rotate-perspective/