06Color-fill-wipe toggle — when the checked value turns on, the box's fill value spreads from one corner to the opposite one

<main class="stage">
<label class="cbw is-demo" id="cbw">
  <input type="checkbox" class="cbw__input" id="cbwInput">
  <span class="cbw__card" id="cbwCard">
    <span class="cbw__fill" id="cbwFill" aria-hidden="true"></span>
    <span class="cbw__box" aria-hidden="true">
      <svg viewBox="0 0 20 20" width="14" height="14"><path d="M4 10.5l3.5 3.5L16 5.5" fill="none" stroke="currentColor" stroke-width="2.6" stroke-linecap="round" stroke-linejoin="round"/></svg>
    </span>
    <span class="cbw__text">Select notification card</span>
  </span>
</label>
</main>

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

// 계산 겹: index.html measure() 가 카드의 실측 대각선 길이(getBoundingClientRect)를 재고,
// clip-path circle() 반지름을 easeOutCubic 로 그 길이까지 rAF 적분해 한쪽 모서리에서
// 반대쪽 모서리까지 채움 배경이 번지는 값을 만든다.
@include stage($stage-orange);

.cbw {
  cursor: pointer;
  user-select: none;
  display: block;
}

.cbw__input {
  position: absolute;
  width: 1px;
  height: 1px;
  opacity: 0;
  pointer-events: none;
}

.cbw__card {
  position: relative;
  display: flex;
  align-items: center;
  gap: $sp-3;
  width: 220px;
  padding: $sp-4 $sp-5;
  border-radius: $r-card;
  background: rgba($subject-cream, .14);
  border: 1px solid rgba($subject-cream, .3);
  overflow: hidden;
  box-sizing: border-box;
}

.cbw__fill {
  position: absolute;
  inset: 0;
  background: $subject-blue;
  clip-path: circle(0px at 0% 100%);
  pointer-events: none;
}

.cbw__box {
  position: relative;
  z-index: 1;
  flex: 0 0 auto;
  width: 22px;
  height: 22px;
  border-radius: $r-sm;
  border: 2px solid rgba($subject-cream, .6);
  color: $subject-cream;
  display: grid;
  place-items: center;
  box-sizing: border-box;

  svg {
    opacity: 0;
    transition: opacity $dur-quick $ease-out;
  }
}

.cbw__input:checked ~ .cbw__card .cbw__box svg {
  opacity: 1;
}

.cbw__text {
  position: relative;
  z-index: 1;
  color: $subject-cream;
  font-size: 14px;
  font-weight: 600;
}

.cbw__input:focus-visible ~ .cbw__card {
  outline: 2px solid $subject-blue-light;
  outline-offset: 2px;
}

@media (max-width: 340px) {
  .cbw__card { width: 100%; max-width: 220px; }
  .cbw__text { font-size: 13px; }
}

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

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

.stage {
  box-sizing: border-box;
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #ff4d1f;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.cbw {
  cursor: pointer;
  user-select: none;
  display: block;
}

.cbw__input {
  position: absolute;
  width: 1px;
  height: 1px;
  opacity: 0;
  pointer-events: none;
}

.cbw__card {
  position: relative;
  display: flex;
  align-items: center;
  gap: 12px;
  width: 220px;
  padding: 16px 20px;
  border-radius: 16px;
  background: rgba(255, 247, 230, 0.14);
  border: 1px solid rgba(255, 247, 230, 0.3);
  overflow: hidden;
  box-sizing: border-box;
}

.cbw__fill {
  position: absolute;
  inset: 0;
  background: #2f6df6;
  clip-path: circle(0px at 0% 100%);
  pointer-events: none;
}

.cbw__box {
  position: relative;
  z-index: 1;
  flex: 0 0 auto;
  width: 22px;
  height: 22px;
  border-radius: 8px;
  border: 2px solid rgba(255, 247, 230, 0.6);
  color: #fff7e6;
  display: grid;
  place-items: center;
  box-sizing: border-box;
}
.cbw__box svg {
  opacity: 0;
  transition: opacity 220ms ease-out;
}

.cbw__input:checked ~ .cbw__card .cbw__box svg {
  opacity: 1;
}

.cbw__text {
  position: relative;
  z-index: 1;
  color: #fff7e6;
  font-size: 14px;
  font-weight: 600;
}

.cbw__input:focus-visible ~ .cbw__card {
  outline: 2px solid #5b8cf8;
  outline-offset: 2px;
}

@media (max-width: 340px) {
  .cbw__card {
    width: 100%;
    max-width: 220px;
  }
  .cbw__text {
    font-size: 13px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .cbw__fill {
    transition: none;
  }
  .cbw__box svg {
    transition: none;
  }
}

(function () {
  var WIPE_MS = 420; // 계산 겹 상수: 채움이 한쪽 모서리에서 반대쪽까지 번지는 데 걸리는 실제 시간(ms)
  var CYCLE_MS = 900; // 자동 루프가 체크·해제를 오가는 간격
  var reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;

  var root = document.getElementById('cbw');
  var input = document.getElementById('cbwInput');
  var card = document.getElementById('cbwCard');
  var fill = document.getElementById('cbwFill');

  var isDemo = true;
  var diag = 0;
  var wiping = false, wipeStart = 0, wipeDir = 1;

  function measure() {
    // 계산 겹: 카드 실측 대각선 길이 — 채움 원이 반대쪽 모서리에 정확히 닿는 반지름 값
    var r = card.getBoundingClientRect();
    diag = Math.sqrt(r.width * r.width + r.height * r.height);
  }

  function easeOutCubic(t) { return 1 - Math.pow(1 - t, 3); }

  function human() {
    if (isDemo) { root.classList.remove('is-demo'); isDemo = false; }
  }

  function setChecked(next, ts) {
    input.checked = next;
    wipeDir = next ? 1 : -1;
    wipeStart = ts;
    wiping = true;
  }

  input.addEventListener('change', function () {
    human();
    setChecked(input.checked, performance.now());
  });

  var cycleStart = 0;
  var lastState = false;

  function loop(ts) {
    if (!cycleStart) cycleStart = ts;
    if (!diag) measure();

    if (isDemo) {
      var step = Math.floor((ts - cycleStart) / CYCLE_MS) % 2 === 1;
      if (step !== lastState) { lastState = step; setChecked(step, ts); }
    }

    if (wiping) {
      var t = Math.min(1, (ts - wipeStart) / WIPE_MS);
      var p = easeOutCubic(t);
      var r = wipeDir === 1 ? p * diag : (1 - p) * diag;
      fill.style.clipPath = 'circle(' + r.toFixed(1) + 'px at 0% 100%)';
      if (t >= 1) wiping = false;
    }

    requestAnimationFrame(loop);
  }

  window.addEventListener('resize', measure);
  measure();
  if (reduce) { WIPE_MS = 1; }
  requestAnimationFrame(loop);
})();

// ColorFillWipe — vanilla 판(run/368/demo/06-custom-checkbox-color-fill-wipe/index.html) 의 React 포트.
// 카드의 실측 대각선 길이(getBoundingClientRect)를 재고, clip-path circle() 반지름을
// easeOutCubic 로 그 길이까지 rAF 적분해 한쪽 모서리에서 반대쪽까지 채움 배경을 만든다.
import { useEffect, useRef } from "react";
import styles from "./ColorFillWipe.module.scss";

type Box<T> = { current: T };

export default function ColorFillWipe() {
  const rootRef = useRef(null) as unknown as Box<HTMLLabelElement>;
  const inputRef = useRef(null) as unknown as Box<HTMLInputElement>;
  const cardRef = useRef(null) as unknown as Box<HTMLSpanElement>;
  const fillRef = useRef(null) as unknown as Box<HTMLSpanElement>;
  const rafRef = useRef(0) as unknown as Box<number>;

  useEffect(() => {
    let WIPE_MS = 420; // 계산 겹 상수: 채움이 한쪽 모서리에서 반대쪽까지 번지는 데 걸리는 실제 시간(ms)
    const CYCLE_MS = 900; // 자동 루프가 체크·해제를 오가는 간격
    const reduce = window.matchMedia("(prefers-reduced-motion: reduce)").matches;

    const root = rootRef.current;
    const input = inputRef.current;
    const card = cardRef.current;
    const fill = fillRef.current;
    if (!root || !input || !card || !fill) return;

    let isDemo = true;
    let diag = 0;
    let wiping = false, wipeStart = 0, wipeDir = 1;

    function measure() {
      // 계산 겹: 카드 실측 대각선 길이 — 채움 원이 반대쪽 모서리에 정확히 닿는 반지름 값
      const r = card!.getBoundingClientRect();
      diag = Math.sqrt(r.width * r.width + r.height * r.height);
    }

    function easeOutCubic(t: number) { return 1 - Math.pow(1 - t, 3); }

    function human() {
      if (isDemo) { root!.classList.remove(styles.isDemo); isDemo = false; }
    }

    function setChecked(next: boolean, ts: number) {
      input!.checked = next;
      wipeDir = next ? 1 : -1;
      wipeStart = ts;
      wiping = true;
    }

    function onChange() { human(); setChecked(input!.checked, performance.now()); }
    input.addEventListener("change", onChange);

    let cycleStart = 0;
    let lastState = false;

    function loop(ts: number) {
      if (!cycleStart) cycleStart = ts;
      if (!diag) measure();

      if (isDemo) {
        const step = Math.floor((ts - cycleStart) / CYCLE_MS) % 2 === 1;
        if (step !== lastState) { lastState = step; setChecked(step, ts); }
      }

      if (wiping) {
        const t = Math.min(1, (ts - wipeStart) / WIPE_MS);
        const p = easeOutCubic(t);
        const r = wipeDir === 1 ? p * diag : (1 - p) * diag;
        fill!.style.clipPath = "circle(" + r.toFixed(1) + "px at 0% 100%)";
        if (t >= 1) wiping = false;
      }

      rafRef.current = requestAnimationFrame(loop);
    }

    function onResize() { measure(); }
    window.addEventListener("resize", onResize);
    measure();
    if (reduce) { WIPE_MS = 1; }
    rafRef.current = requestAnimationFrame(loop);

    return () => {
      input.removeEventListener("change", onChange);
      window.removeEventListener("resize", onResize);
      cancelAnimationFrame(rafRef.current);
    };
  }, []);

  return (
    <main className={styles.stage}>
      <label className={styles.cbw + " " + styles.isDemo} ref={rootRef}>
        <input type="checkbox" className={styles.cbwInput} ref={inputRef} />
        <span className={styles.cbwCard} ref={cardRef}>
          <span className={styles.cbwFill} ref={fillRef} aria-hidden="true" />
          <span className={styles.cbwBox} aria-hidden="true">
            <svg viewBox="0 0 20 20" width={14} height={14}>
              <path d="M4 10.5l3.5 3.5L16 5.5" fill="none" stroke="currentColor" strokeWidth={2.6} strokeLinecap="round" strokeLinejoin="round" />
            </svg>
          </span>
          <span className={styles.cbwText}>알림 카드 선택</span>
        </span>
      </label>
    </main>
  );
}