@atlaskit/adf-schema/dist/es2019/utils/clamp-lightness.js

Shared package that contains the ADF-schema (json) and ProseMirror node/mark specs

import { rgbFromHex } from './rgb-from-hex';
import { rgbToLch } from './rgb-to-lch';
const clamp = (i, min, max) => Math.round(Math.min(Math.max(i, min), max));
const rgbToHex = ({
  r,
  g,
  b
}) => {
  const convertComponent = c => {
    const cBase16 = c.toString(16);
    return cBase16.length === 1 ? `0${cBase16}` : cBase16;
  };
  return `#${convertComponent(r)}${convertComponent(g)}${convertComponent(b)}`;
};
const lchToLab = ({
  l,
  c,
  h
}) => {
  const convertH = Number.isNaN(h) ? 0 : h * (Math.PI / 180);
  return {
    l,
    a: Math.cos(convertH) * c,
    b: Math.sin(convertH) * c
  };
};
const labToXyz = ({
  l,
  a,
  b
}) => {
  const convertComponent = c => c > 0.206896552 ? Math.pow(c, 3) : 0.12841855 * (c - 0.137931034);
  const y = (l + 16) / 116;
  const x = a / 500 + y;
  const z = y - b / 200;
  return {
    x: convertComponent(x) * 0.95047,
    y: convertComponent(y),
    z: convertComponent(z) * 1.08883
  };
};
const xyzToRgb = ({
  x,
  y,
  z
}) => {
  const convertComponent = c => 255 * (c <= 0.00304 ? 12.92 * c : 1.055 * Math.pow(c, 1 / 2.4) - 0.055);
  return {
    r: clamp(convertComponent(3.2404542 * x - 1.5371385 * y - 0.4985314 * z), 0, 255),
    g: clamp(convertComponent(-0.969266 * x + 1.8760108 * y + 0.041556 * z), 0, 255),
    b: clamp(convertComponent(0.0556434 * x - 0.2040259 * y + 1.0572252 * z), 0, 255)
  };
};
const lchToRgb = lch => xyzToRgb(labToXyz(lchToLab(lch)));
export const clampLightness = (color, newPercent) => {
  const rgb = rgbFromHex(color);
  if (rgb === null) {
    return color;
  }

  // LCH (rather than HSL) gives the best results here as the L component in LCH is based on human color perception
  const lch = rgbToLch(rgb);
  lch.l = clamp(newPercent, 0, 100);
  return rgbToHex(lchToRgb(lch));
};