color_grade — GFX2D post op

• Data kinds: rgb × lut → rgb

• Call: import gfx2d; gfx2d.color_grade(rgb, lut) (or opsgfx2d.get("color_grade"))

Usage

Apply a 3-D colour LUT to an `rgb` image by trilinear interpolation.

`lut is (n, n, n, 3) indexed [r, g, b]` — the layout

:func:color_lut produces. The identity LUT returns the input to within

float64 rounding (measured maximum 3.3e-16), which is what makes this

testable without a reference implementation: trilinear interpolation of a

coordinate function is that coordinate, exactly.

References (sample data, literature)

• Sample-data catalog (download URLs / licences) — 2-D uses skimage.data (BSD/public domain) plus synthetic images; 3-D lists download URLs for real data sources (Stanford, PDS, …).

• Operator provenance and references — the sources of the research/methods this op family came from.

• The canonical algorithm (author, year) and its uses are named in the family usage guide above.

Runnable examples (verified samples that actually call this op)

• gfx2d_scene — py -3.11 examples/gfx2d_scene.py

Ops the type connects to (they accept rgb as input)

srgb_to_linear · linear_to_srgb · blend_mode · light_mask · normal_map_decode · bloom · vignette · chromatic_aberration

Same category (post)

bloom · vignette · chromatic_aberration · film_grain · color_lut · dither · palette_quantize

*Provenance: gfx2d.py — GFX2D operator registry. This per-op note is generated by tools/opdocs.py md (do not hand-edit).*

© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.