feat: add render graph driven renderer architecture

Amp-Thread-ID: https://ampcode.com/threads/T-019f9d91-77c1-7206-a60f-ed6554ce92ab

Co-authored-by: Heaust Azure <heaust.azure@gmail.com>

vendor/fxnode/test/oklab.test.ts

@@ -0,0 +1,22 @@
+import test from "node:test";
+import assert from "node:assert/strict";
+import { isInSrgbGamut, mapOklchToSrgb, maxSrgbChroma, oklabToOklch, srgbToOklab } from "@lib/color/oklab.js";
+test("Oklab conversion matches reference primaries", () => {
+  const red = srgbToOklab([1, 0, 0]);
+  assert.ok(Math.abs(red.l - 0.627955) < 1e-5);
+  assert.ok(Math.abs(red.a - 0.224863) < 1e-5);
+  assert.ok(Math.abs(red.b - 0.125846) < 1e-5);
+  const white = srgbToOklab([1, 1, 1]);
+  assert.ok(Math.abs(white.l - 1) < 1e-6);
+});
+test("Oklch gamut mapping preserves lightness and hue by reducing chroma", () => {
+  const requested = { l: 0.65, c: 0.6, h: 1.2 },
+    limit = maxSrgbChroma(requested.l, requested.h);
+  assert.ok(limit < requested.c);
+  assert.equal(isInSrgbGamut({ ...requested, c: limit }), true);
+  const rgb = mapOklchToSrgb(requested);
+  assert.ok(rgb.every((value) => value >= 0 && value <= 1));
+  const mapped = oklabToOklch(srgbToOklab(rgb));
+  assert.ok(Math.abs(mapped.l - requested.l) < 2e-5);
+  assert.ok(Math.abs(mapped.h - requested.h) < 2e-4);
+});