Oni Colors

Standalone Odin color package. Depends only on core:math — no other dependencies.

Oni Colors is the shared color model that provides sRGB RGBA, a Tailwind-style named palette, alternate color spaces (hex, HSL, HWB, LCH, OKLCH), and conversions to byte and normalized float channels.

Quick start

import col "libs:colors"

red := col.css_color_to_rgba(.RED_500)
tint := col.to_rgba_color(col.Hex(0xFF0000FF))
clear := col.color_to_f32(col.Colors(col.Color.BACKGROUND))

Types

Type	Description
`RGBA`	8-bit sRGB channels `{r, g, b, a}`
`Color`	Named palette enum (semantic tokens + Tailwind shades)
`Hex`	Packed `#RRGGBBAA` as `distinct u32`
`HSLA`	Hue °, saturation/lightness/alpha in 0–1
`HWBA`	Hue °, whiteness/blackness/alpha in 0–1
`LCHA`	CIE LCH: L 0–100, chroma ≥ 0, hue °, alpha 0–1
`OKLCHA`	OKLCH: L 0–1, chroma ≥ 0, hue °, alpha 0–1
`Colors`	Union of the static variants above
`Palette`	`[Color]RGBA`

Palette

palette is the default table keyed by Color. Semantic entries (.PRIMARY, .BACKGROUND, …) ship with Oni-oriented defaults; shade scales (.RED_50 … .TAUPE_950) follow Tailwind CSS v4 sRGB values.

fg := col.palette[.FOREGROUND]
accent := col.css_color_to_rgba(.BLUE_500)

.INVALID and .INHERIT resolve to empty RGBA via css_color_to_rgba (inherit is for host UI layers; this package does not walk a style stack).

Conversions

Normalize any concrete space to RGBA:

to_rgba_color :: proc { ... } // overload set

Input	Proc
`Color`	`css_color_to_rgba` / `css_color_to_rba`
`RGBA`	`rgba_to_rgba` (identity)
`Hex`	`hex_to_rgba`
`HSLA`	`hsla_to_rgba`
`HWBA`	`hwba_to_rgba`
`LCHA`	`lcha_to_rgba`
`OKLCHA`	`oklcha_to_rgba`

For GPU / shaders:

rgba_to_f32(c)   // RGBA → [4]f32 in 0–1
color_to_f32(c)  // Colors → [4]f32 (`.INVALID` → zero)

With Oni

Oni re-exports these types as o.Color, o.RGBA, etc., and extends Colors with a widget callback variant plus context-aware to_rgba for .INHERIT and procs. Import this package directly when you do not need that UI layer.

Tests

odin test colors -vet -strict-style

colors_test.odin covers API/branch behavior for every public conversion helper.

colors_external_test.odin + colors_external_goldens.odin audit external correctness:

Suite	Source of truth
All 286 Tailwind shades	Official `theme.css` OKLCH → sRGB via ColorAide
OKLCH → sRGB	WPT `css/css-color/oklch-*.html` (CSS Color Level 4)
LCH → sRGB	ColorAide `lch-d65` (CIE Lab D65; matches this package)
HSL / HWB	CSS Color Level 4 / WPT vectors
Semantic theme tokens	Frozen Oni palette goldens (not Tailwind)

CSS Color 4 / WPT lch() uses D50 Lab; this package uses D65. A dedicated test asserts that divergence so a silent white-point change is visible.