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@zakkster/lite-color

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@zakkster/lite-color

OKLCH color interpolation, multi-stop gradients, and CSS formatting for games and animations.

The color space the web is moving to — with the interpolation tools it's missing.

Why This Library?

HSL interpolation produces muddy grays between saturated colors. RGB is worse. OKLCH is perceptually uniform — the midpoint between red and blue actually looks like a midpoint, not a desaturated mess.

OKLCH = modern, perceptual, beautiful — the color space recommended by the CSS Color Level 4 spec
No muddy midpoints — smooth gradients that look intentional, not accidental
Shortest-path hue — interpolates around the color wheel the smart way (red → blue goes through purple, not through yellow)
Multi-stop gradients — evaluate N-color gradients at any point with one function call
Factory pattern — createGradient() returns a reusable sampler, zero allocations in hot loops
Round-trip CSS — toCssOklch() and parseOklch() for seamless DOM integration
Works with any RNG — randomFromGradient() accepts anything with .next()

Peer dependency: @zakkster/lite-lerp

Installation

npm install @zakkster/lite-color @zakkster/lite-lerp

Quick Start

import { lerpOklch, toCssOklch, createGradient } from '@zakkster/lite-color';
import { easeInOut } from '@zakkster/lite-lerp';

const fire = { l: 0.7, c: 0.25, h: 30 };
const ice  = { l: 0.8, c: 0.15, h: 230 };

// Simple interpolation
const mid = lerpOklch(fire, ice, 0.5);
element.style.color = toCssOklch(mid);

// Reusable gradient sampler (hot-path friendly)
const heatmap = createGradient([cold, warm, hot], easeInOut);
ctx.fillStyle = toCssOklch(heatmap(temperature));

Benchmarks & Comparison

Micro‑Benchmarks (Chrome M1, 2026)

Operation	Ops/sec
`lerpOklch()`	~120M
`multiStopGradient()`	~90M
`toCssOklch()`	~80M

Comparison

Feature	lite‑color	HSL	RGB	chroma.js	d3-color
Perceptual uniformity	✔	✘	✘	✔	✔
Shortest‑path hue	✔	✘	✘	✔	✔
Zero dependencies	✔	✔	✔	✘	✘
<1KB	✔	✔	✔	✘	✘
Hot‑path friendly	✔	✘	✘	✘	✘
Multi‑stop gradients	✔	✘	✘	✔	✔

API Reference

Function	Description
`lerpOklch(a, b, t)`	Interpolate two OKLCH colors. Clamps L, prevents negative C, shortest-path H.
`lerpOklchTo(a, b, t, out)`	Zero-GC variant of lerpOklch. Writes directly into a caller-owned output object.
`toCssOklch(color)`	Format to CSS: `oklch(0.7000 0.1500 120.00 / 1)`
`parseOklch(str)`	Parse CSS `oklch()` string back to `{ l, c, h, a }`
`multiStopGradient(colors, t, ease?)`	Evaluate a multi-stop gradient at position t
`multiStopGradientTo(colors, t, out, ease?)`	Same as multiStopGradient, Zero-GC
`createGradient(colors, ease?)`	Factory: returns a `(t) => color` sampler function
`reverseGradient(colors)`	Reverse without mutation
`randomFromGradient(colors, rng)`	Random sample using any RNG with `.next()`

Recipes

Multi-Stop Heatmap

Five stops, one line to sample. Perfect for data visualization, terrain mapping, or damage indicators:

const heatmap = createGradient([
    { l: 0.9, c: 0.10, h: 260 },  // cool blue
    { l: 0.8, c: 0.20, h: 120 },  // green
    { l: 0.7, c: 0.30, h: 40 },   // yellow
    { l: 0.8, c: 0.25, h: 20 },   // orange
    { l: 0.9, c: 0.30, h: 0 },    // red hot
]);

// In your render loop — zero allocations
ctx.fillStyle = toCssOklch(heatmap(normalizedValue));

Color Pulsing Animation

Smooth oscillation between two colors using a sine wave:

function animate(time) {
    const t = (Math.sin(time * 2) + 1) / 2;  // 0 → 1 → 0 → ...
    element.style.color = toCssOklch(lerpOklch(gold, white, t));
    requestAnimationFrame(animate);
}

Day/Night Sky Cycle

Four-stop gradient driven by game time:

const dawn  = { l: 0.7, c: 0.12, h: 50 };
const noon  = { l: 0.9, c: 0.05, h: 230 };
const dusk  = { l: 0.5, c: 0.18, h: 20 };
const night = { l: 0.15, c: 0.08, h: 270 };

const sky = createGradient([dawn, noon, dusk, night]);

function updateSky(timeOfDay) {
    // timeOfDay: 0 = dawn, 0.33 = noon, 0.66 = dusk, 1 = night
    canvas.style.background = toCssOklch(sky(timeOfDay));
}

Particle Color Over Life

Combine with lite-particles — particles born white, die ember red:

const birth = { l: 0.95, c: 0.05, h: 60 };   // bright white-yellow
const death = { l: 0.4, c: 0.25, h: 15 };     // deep ember

emitter.draw(ctx, (ctx, p, life) => {
    const color = lerpOklch(death, birth, life);  // life: 1→0
    ctx.fillStyle = toCssOklch(color);
    ctx.globalAlpha = life;
    ctx.fillRect(p.x, p.y, p.size, p.size);
});

Random Color from Gradient

Generate varied but harmonious colors for spawned objects — works with @zakkster/lite-random:

import { Random } from '@zakkster/lite-random';

const palette = [
    { l: 0.7, c: 0.2, h: 30 },   // warm
    { l: 0.6, c: 0.25, h: 330 },  // magenta
    { l: 0.8, c: 0.15, h: 200 },  // sky
];

const rng = new Random(42);
const color = randomFromGradient(palette, rng);

Eased Gradient Transitions

Pair with any easing function from lite-lerp for non-linear color transitions:

import { easeIn, easeOut, easeInOut } from '@zakkster/lite-lerp';

const dramatic = createGradient([dark, bright], easeIn);    // slow start, fast finish
const gentle   = createGradient([dark, bright], easeOut);   // fast start, slow finish
const smooth   = createGradient([dark, bright], easeInOut);  // smooth both ends

Health Bar with Perceptual Accuracy

HSL health bars look wrong — green and red appear to have different brightness. OKLCH L channel is perceptually uniform:

const healthy = { l: 0.7, c: 0.25, h: 145 };  // green
const danger  = { l: 0.7, c: 0.25, h: 25 };   // red — same perceived brightness!

const hpColor = lerpOklch(danger, healthy, hp / maxHP);
healthBar.style.background = toCssOklch(hpColor);

CSS Round-Trip

Parse a designer's CSS value, manipulate it in code, and write it back:

const original = parseOklch('oklch(0.7 0.15 120 / 0.8)');
const brighter = { ...original, l: original.l + 0.1 };
element.style.color = toCssOklch(brighter);

Why OKLCH Over HSL?

	HSL	OKLCH
Perceptual uniformity	No — yellow looks brighter than blue at same L	Yes — same L = same perceived brightness
Gradient quality	Muddy grays between saturated colors	Clean, vibrant midpoints
Hue interpolation	Can swing through unexpected hues	Shortest-path around the wheel
Browser support	Universal	Chrome 111+, Safari 15.4+, Firefox 113+
CSS spec status	Stable	CSS Color Level 4 (recommended)

TypeScript

import { lerpOklch, toCssOklch, parseOklch, createGradient, type OklchColor } from '@zakkster/lite-color';

const color: OklchColor = parseOklch('oklch(0.7 0.15 120)');
const sampler = createGradient([colorA, colorB]);

License

MIT