05Figma panel — a color picker that keeps three notations recomputed in sync

<main class="stage">
<section class="panel">
  <div class="swatch" id="swatch"></div>
  <dl class="fields">
    <div class="field">
      <dt class="fieldLabel">HEX</dt>
      <dd class="fieldValue" id="hexField">#000000</dd>
    </div>
    <div class="field">
      <dt class="fieldLabel">RGB</dt>
      <dd class="fieldValue" id="rgbField">rgb(0, 0, 0)</dd>
    </div>
    <div class="field">
      <dt class="fieldLabel">HSL</dt>
      <dd class="fieldValue" id="hslField">hsl(0deg 0% 0%)</dd>
    </div>
  </dl>
</section>
</main>

@use "../../../../site/static/demo-tokens" as *;

@include stage($stage-ink);

.panel {
  display: flex;
  flex-direction: column;
  align-items: stretch;
  gap: $sp-4;
  width: 100%;
  max-width: 220px;
}

.swatch {
  height: 64px;
  border-radius: $r-card;
  box-shadow: $shadow-raised;
}

.fields {
  display: flex;
  flex-direction: column;
  gap: $sp-2;
  margin: 0;
}

.field {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: $sp-2;
  padding: $sp-2 $sp-3;
  border-radius: $r-sm;
  background: rgba($subject-cream, .08);
}

.fieldLabel {
  margin: 0;
  color: $subject-cream;
  opacity: .82;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  font-weight: 600;
  font-size: 10px;
  line-height: 1.3;
  letter-spacing: .04em;
}

.fieldValue {
  margin: 0;
  color: $subject-cream;
  font-family: "Space Mono", ui-monospace, monospace;
  font-weight: 700;
  font-size: 12px;
  line-height: 1.3;
}

@media (max-width: 340px) {
  .panel { max-width: 168px; }
  .swatch { height: 48px; }
  .fieldValue { font-size: 11px; }
}

@media (prefers-reduced-motion: reduce) {
  .swatch { transition: none; }
}

html, body {
  margin: 0;
  overflow: hidden;
}

.stage {
  box-sizing: border-box;
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #17141a;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.panel {
  display: flex;
  flex-direction: column;
  align-items: stretch;
  gap: 16px;
  width: 100%;
  max-width: 220px;
}

.swatch {
  height: 64px;
  border-radius: 16px;
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
}

.fields {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin: 0;
}

.field {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  padding: 8px 12px;
  border-radius: 8px;
  background: rgba(255, 247, 230, 0.08);
}

.fieldLabel {
  margin: 0;
  color: #fff7e6;
  opacity: 0.82;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  font-weight: 600;
  font-size: 10px;
  line-height: 1.3;
  letter-spacing: 0.04em;
}

.fieldValue {
  margin: 0;
  color: #fff7e6;
  font-family: "Space Mono", ui-monospace, monospace;
  font-weight: 700;
  font-size: 12px;
  line-height: 1.3;
}

@media (max-width: 340px) {
  .panel {
    max-width: 168px;
  }
  .swatch {
    height: 48px;
  }
  .fieldValue {
    font-size: 11px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .swatch {
    transition: none;
  }
}

// Figma 패널(05) — 하나의 색 값을 HEX·RGB·HSL 세 표기법으로 각각 다시 계산해,
// 세 필드가 항상 같은 색을 가리키도록 서로 맞춘다. 실키·실서버 요청 없음.
(function () {
  var swatchEl = document.getElementById('swatch');
  var hexField = document.getElementById('hexField');
  var rgbField = document.getElementById('rgbField');
  var hslField = document.getElementById('hslField');
  if (!swatchEl || !hexField || !rgbField || !hslField) return;
  var reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;

  var CYCLE_MS = 2600;
  var PRESETS = [
    { h: 10, s: 72, l: 54 },
    { h: 70, s: 60, l: 48 },
    { h: 130, s: 55, l: 42 },
    { h: 190, s: 65, l: 50 },
    { h: 250, s: 60, l: 58 },
    { h: 310, s: 68, l: 52 },
    { h: 370, s: 72, l: 54 }
  ];
  var SEG_MS = CYCLE_MS / (PRESETS.length - 1);

  function hslToRgb(h, s, l) {
    h = h % 360;
    s /= 100; l /= 100;
    var k = function (n) { return (n + h / 30) % 12; };
    var a = s * Math.min(l, 1 - l);
    var f = function (n) { return l - a * Math.max(-1, Math.min(k(n) - 3, Math.min(9 - k(n), 1))); };
    return [Math.round(f(0) * 255), Math.round(f(8) * 255), Math.round(f(4) * 255)];
  }

  function toHex(n) {
    return n.toString(16).padStart(2, '0');
  }

  function apply(t) {
    var idx = Math.min(PRESETS.length - 2, Math.floor(t / SEG_MS));
    var frac = (t % SEG_MS) / SEG_MS;
    var a = PRESETS[idx];
    var b = PRESETS[idx + 1];
    var h = a.h + (b.h - a.h) * frac;
    var s = a.s + (b.s - a.s) * frac;
    var l = a.l + (b.l - a.l) * frac;
    var hMod = h % 360;

    var rgb = hslToRgb(h, s, l);
    var hex = '#' + toHex(rgb[0]) + toHex(rgb[1]) + toHex(rgb[2]);
    var hslStr = 'hsl(' + hMod.toFixed(0) + 'deg ' + s.toFixed(0) + '% ' + l.toFixed(0) + '%)';
    var rgbStr = 'rgb(' + rgb[0] + ', ' + rgb[1] + ', ' + rgb[2] + ')';

    swatchEl.style.background = hslStr;
    hexField.textContent = hex;
    rgbField.textContent = rgbStr;
    hslField.textContent = hslStr;
  }

  if (reduce) {
    apply(0);
    return;
  }

  var start = null;
  function loop(ts) {
    if (start === null) start = ts;
    var t = (ts - start) % CYCLE_MS;
    apply(t);
    requestAnimationFrame(loop);
  }
  requestAnimationFrame(loop);
})();

import { useEffect, useRef } from "react";
import styles from "./ColorPickerFigmaPanel.module.scss";

// Figma 패널 — 하나의 색 값을 HEX·RGB·HSL 세 표기법으로 각각 다시 계산해,
// 세 필드가 항상 같은 색을 가리키도록 서로 맞춘다. 실키·실서버 요청 없음.
const CYCLE_MS = 2600;
const PRESETS = [
  { h: 10, s: 72, l: 54 },
  { h: 70, s: 60, l: 48 },
  { h: 130, s: 55, l: 42 },
  { h: 190, s: 65, l: 50 },
  { h: 250, s: 60, l: 58 },
  { h: 310, s: 68, l: 52 },
  { h: 370, s: 72, l: 54 },
];
const SEG_MS = CYCLE_MS / (PRESETS.length - 1);

function hslToRgb(h: number, s: number, l: number): [number, number, number] {
  h = h % 360;
  s /= 100;
  l /= 100;
  const k = (n: number) => (n + h / 30) % 12;
  const a = s * Math.min(l, 1 - l);
  const f = (n: number) => l - a * Math.max(-1, Math.min(k(n) - 3, Math.min(9 - k(n), 1)));
  return [Math.round(f(0) * 255), Math.round(f(8) * 255), Math.round(f(4) * 255)];
}

function toHex(n: number) {
  return n.toString(16).padStart(2, "0");
}

export default function ColorPickerFigmaPanel() {
  const swatchRef = useRef<HTMLDivElement>(null);
  const hexRef = useRef<HTMLElement>(null);
  const rgbRef = useRef<HTMLElement>(null);
  const hslRef = useRef<HTMLElement>(null);

  useEffect(() => {
    const swatch = swatchRef.current;
    const hexField = hexRef.current;
    const rgbField = rgbRef.current;
    const hslField = hslRef.current;
    if (!swatch || !hexField || !rgbField || !hslField) return;
    const reduce = window.matchMedia("(prefers-reduced-motion: reduce)").matches;

    function apply(t: number) {
      const idx = Math.min(PRESETS.length - 2, Math.floor(t / SEG_MS));
      const frac = (t % SEG_MS) / SEG_MS;
      const a = PRESETS[idx];
      const b = PRESETS[idx + 1];
      const h = a.h + (b.h - a.h) * frac;
      const s = a.s + (b.s - a.s) * frac;
      const l = a.l + (b.l - a.l) * frac;
      const hMod = h % 360;

      const rgb = hslToRgb(h, s, l);
      const hex = "#" + toHex(rgb[0]) + toHex(rgb[1]) + toHex(rgb[2]);
      const hslStr = `hsl(${hMod.toFixed(0)}deg ${s.toFixed(0)}% ${l.toFixed(0)}%)`;
      const rgbStr = `rgb(${rgb[0]}, ${rgb[1]}, ${rgb[2]})`;

      swatch!.style.background = hslStr;
      hexField!.textContent = hex;
      rgbField!.textContent = rgbStr;
      hslField!.textContent = hslStr;
    }

    if (reduce) {
      apply(0);
      return;
    }

    let start: number | null = null;
    let raf = 0;
    function loop(ts: number) {
      if (start === null) start = ts;
      const t = (ts - start) % CYCLE_MS;
      apply(t);
      raf = requestAnimationFrame(loop);
    }
    raf = requestAnimationFrame(loop);
    return () => cancelAnimationFrame(raf);
  }, []);

  return (
    <div className={styles.stage}>
      <section className={styles.panel}>
        <div className={styles.swatch} ref={swatchRef} />
        <dl className={styles.fields}>
          <div className={styles.field}>
            <dt className={styles.fieldLabel}>HEX</dt>
            <dd className={styles.fieldValue} ref={hexRef}>#000000</dd>
          </div>
          <div className={styles.field}>
            <dt className={styles.fieldLabel}>RGB</dt>
            <dd className={styles.fieldValue} ref={rgbRef}>rgb(0, 0, 0)</dd>
          </div>
          <div className={styles.field}>
            <dt className={styles.fieldLabel}>HSL</dt>
            <dd className={styles.fieldValue} ref={hslRef}>hsl(0deg 0% 0%)</dd>
          </div>
        </dl>
      </section>
    </div>
  );
}