vignette — GFX2D post op

• Data kinds: rgb → rgb

• Call: import gfx2d; gfx2d.vignette(rgb, strength=0.6, radius=1.0, power=2.0) (or opsgfx2d.get("vignette"))

Usage

Darken towards the corners: `out = rgb * (1 - strength * t**power)`.

`t is the distance from the geometric centre ((h-1)/2, (w-1)/2)`

divided by `radius` times the half-diagonal, clipped at 1. The factor at

`t = 0 is exactly 1, so strength=0` is the exact identity and — for an

odd-sized image, where a pixel actually sits on the centre — that pixel

is returned untouched. An even-sized image has no centre pixel: its four

innermost pixels are 0.707 px out and are already attenuated, which is

geometry rather than a rounding error.

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 · chromatic_aberration · film_grain

Same category (post)

bloom · chromatic_aberration · film_grain · color_lut · color_grade · 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.