brightness_contrast — GFX2D isp op

• Data kinds: rgb → rgb

• Call: import fullseye as fs; fs.ledger.brightness_contrast(rgb, brightness=0.0, contrast=1.0) (to call the implementation directly, import gfx2d; gfx2d.brightness_contrast(rgb, brightness=0.0, contrast=1.0); from the registry, opsgfx2d.get("brightness_contrast"))

Usage

`out = (rgb - 0.5) * contrast + 0.5 + brightness, clipped to [0, 1]`.

Contrast pivots about mid-grey so `contrast=2` doubles the distance from

0.5 and leaves 0.5 alone; brightness is an additive offset. Ground truth:

`(0, 1)` is the exact identity; mid-grey is invariant to any contrast.

Raises `ValueError: *brightness* outside [-1, 1]` or *contrast* < 0.

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)

• raw_to_display_isp — py -3.11 examples/raw_to_display_isp.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 (isp)

raw_black_level · raw_dead_pixel_mask · raw_dead_pixel_correct · lens_shading_gain · lens_shading_correct · awb_gains · rgb_apply_gains · raw_apply_gains

*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.