01文字と点が入れ替わる目のアイコンのモーフ

<main class="stage">
<div class="pem is-demo" id="pemRoot">
  <form class="pem__form" id="pemForm" novalidate>
    <label class="pem__field">
      <span class="pem__labelText">パスワード</span>
      <span class="pem__inputWrap">
        <input class="pem__input" id="pemInput" type="password" autocomplete="new-password" spellcheck="false" value="">
        <span class="pem__overlay" id="pemOverlay" aria-hidden="true"></span>
        <button class="pem__toggle" id="pemToggle" type="button" aria-pressed="false" aria-label="パスワードを表示">
          <svg class="pem__eye" viewBox="0 0 24 24" width="22" height="22" aria-hidden="true">
            <path class="pem__lidTop" id="pemLidTop" d="M2,12 Q12,4 22,12" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round"/>
            <path class="pem__lidBottom" id="pemLidBottom" d="M2,12 Q12,20 22,12" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round"/>
            <circle class="pem__pupil" id="pemPupil" cx="12" cy="12" r="3.2" fill="currentColor"/>
          </svg>
        </button>
      </span>
    </label>
  </form>
</div>
</main>

@use "../../../../site/static/demo-tokens" as *;
@include stage($stage-ink);

// 계산 겹: 문자 오버레이는 마스크 점 레이어 위에 실제 글자 레이어를 겹쳐 opacity 크로스페이드로
// 바꾸고, 각 span 의 transition-delay 는 JS 가 인덱스*CHAR_STAGGER_MS 로 순차 계산해 넣는다.
// 눈 아이콘은 JS 가 매 프레임 path d 를 다시 그려 눈꺼풀이 감기고 뜨이는 곡선을 만든다.
.pem {
  position: relative;
  width: min(92vw, calc(160vh - 12.8vw));
  aspect-ratio: 480 / 300;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: center;
}

.pem__form {
  width: 100%;
  max-width: 320px;
  box-sizing: border-box;
}

.pem__field {
  display: grid;
  gap: $sp-2;
}

.pem__labelText {
  color: rgba($subject-cream, .82);
  font-weight: 600;
  font-size: 13px;
  line-height: 1.3;
}

.pem__inputWrap {
  position: relative;
  display: flex;
  align-items: center;
}

.pem__input {
  width: 100%;
  box-sizing: border-box;
  padding: $sp-3 $sp-10 $sp-3 $sp-4;
  border-radius: $r-control;
  border: 0;
  background: rgba($stage-paper, .1);
  color: transparent;
  caret-color: $subject-cream;
  font-weight: 500;
  font-size: 17px;
  line-height: 1.3;
  letter-spacing: .06em;

  &:focus { outline: 2px solid $subject-blue-light; outline-offset: 2px; }
}

.pem__overlay {
  position: absolute;
  left: $sp-4;
  right: $sp-10;
  top: 50%;
  transform: translateY(-50%);
  display: flex;
  pointer-events: none;
  font-weight: 500;
  font-size: 17px;
  line-height: 1.3;
  letter-spacing: .06em;
  color: $subject-cream;
  white-space: nowrap;
  overflow: hidden;
}

.pem__ch {
  position: relative;
  display: inline-grid;
  place-items: center;
  min-width: .62em;
}

.pem__mask,
.pem__char {
  grid-area: 1 / 1;
  transition: opacity $dur-quick $ease-out;
}

.pem__mask { opacity: 1; font-size: 20px; line-height: 1; }
.pem__char { opacity: 0; }

.pem--revealed .pem__mask { opacity: 0; }
.pem--revealed .pem__char { opacity: 1; }

.pem__toggle {
  position: absolute;
  right: $sp-2;
  top: 50%;
  transform: translateY(-50%);
  width: 36px;
  height: 36px;
  display: grid;
  place-items: center;
  border: 0;
  border-radius: $r-pill;
  background: transparent;
  color: rgba($subject-cream, .82);
  cursor: pointer;

  &:hover { background: rgba($stage-paper, .1); }
  &:focus-visible { outline: 2px solid $subject-blue-light; outline-offset: 2px; }
}

.pem__eye { display: block; }

// 배경 톤: 새 계산을 얹지 않고 이미 있는 revealed 신호를 카드 전체 톤으로 넓힌다(077 기준 — 면적은 값의 전파 범위로).
.pem::before {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background: rgba(91, 140, 248, 0);
  transition: background-color .28s ease;
}
.pem--revealed::before {
  background: rgba(91, 140, 248, .16);
}

@media (max-width: 340px) {
  .pem__form { max-width: 260px; }
  .pem__input { font-size: 15px; padding-right: $sp-8; }
  .pem__overlay { font-size: 15px; right: $sp-8; }
}

@media (prefers-reduced-motion: reduce) {
  .pem__mask,
  .pem__char {
    transition: none;
    transition-delay: 0s;
  }
  .pem::before { 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);
}

.pem {
  position: relative;
  width: min(92vw, 160vh - 12.8vw);
  aspect-ratio: 480/300;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: center;
}

.pem__form {
  width: 100%;
  max-width: 320px;
  box-sizing: border-box;
}

.pem__field {
  display: grid;
  gap: 8px;
}

.pem__labelText {
  color: rgba(255, 247, 230, 0.82);
  font-weight: 600;
  font-size: 13px;
  line-height: 1.3;
}

.pem__inputWrap {
  position: relative;
  display: flex;
  align-items: center;
}

.pem__input {
  width: 100%;
  box-sizing: border-box;
  padding: 12px 40px 12px 16px;
  border-radius: 12px;
  border: 0;
  background: rgba(255, 255, 255, 0.1);
  color: transparent;
  caret-color: #fff7e6;
  font-weight: 500;
  font-size: 17px;
  line-height: 1.3;
  letter-spacing: 0.06em;
}
.pem__input:focus {
  outline: 2px solid #5b8cf8;
  outline-offset: 2px;
}

.pem__overlay {
  position: absolute;
  left: 16px;
  right: 40px;
  top: 50%;
  transform: translateY(-50%);
  display: flex;
  pointer-events: none;
  font-weight: 500;
  font-size: 17px;
  line-height: 1.3;
  letter-spacing: 0.06em;
  color: #fff7e6;
  white-space: nowrap;
  overflow: hidden;
}

.pem__ch {
  position: relative;
  display: inline-grid;
  place-items: center;
  min-width: 0.62em;
}

.pem__mask,
.pem__char {
  grid-area: 1/1;
  transition: opacity 220ms ease-out;
}

.pem__mask {
  opacity: 1;
  font-size: 20px;
  line-height: 1;
}

.pem__char {
  opacity: 0;
}

.pem--revealed .pem__mask {
  opacity: 0;
}

.pem--revealed .pem__char {
  opacity: 1;
}

.pem__toggle {
  position: absolute;
  right: 8px;
  top: 50%;
  transform: translateY(-50%);
  width: 36px;
  height: 36px;
  display: grid;
  place-items: center;
  border: 0;
  border-radius: 999px;
  background: transparent;
  color: rgba(255, 247, 230, 0.82);
  cursor: pointer;
}
.pem__toggle:hover {
  background: rgba(255, 255, 255, 0.1);
}
.pem__toggle:focus-visible {
  outline: 2px solid #5b8cf8;
  outline-offset: 2px;
}

.pem__eye {
  display: block;
}

.pem::before {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background: rgba(91, 140, 248, 0);
  transition: background-color 0.28s ease;
}

.pem--revealed::before {
  background: rgba(91, 140, 248, 0.16);
}

@media (max-width: 340px) {
  .pem__form {
    max-width: 260px;
  }
  .pem__input {
    font-size: 15px;
    padding-right: 32px;
  }
  .pem__overlay {
    font-size: 15px;
    right: 32px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .pem__mask,
  .pem__char {
    transition: none;
    transition-delay: 0s;
  }
  .pem::before {
    transition: none;
  }
}

(function () {
  // 기법: 실제 input 의 type 을 password/text 로 진짜 토글하면서, 그 위에 문자별 span 오버레이
  // (점 마스크 레이어 + 실제 글자 레이어)를 얹어 opacity 크로스페이드로 보여준다. input 자체 글자는
  // color:transparent 로 숨기고 caret-color 만 남긴다. 눈 아이콘은 상태 스위치가 아니라 매 프레임
  // 베지어 제어점(ctrlY)을 다시 계산해 눈꺼풀이 감기고 뜨이는 것처럼 그린다.
  var root = document.getElementById('pemRoot');
  var form = document.getElementById('pemForm');
  var input = document.getElementById('pemInput');
  var overlay = document.getElementById('pemOverlay');
  var toggle = document.getElementById('pemToggle');
  var lidTop = document.getElementById('pemLidTop');
  var lidBottom = document.getElementById('pemLidBottom');
  var pupil = document.getElementById('pemPupil');

  var EYE_MORPH_MS = 260;
  var CHAR_STAGGER_MS = 28;

  function seedRand(seed) {
    var s = seed >>> 0;
    return function () { s = (s * 1664525 + 1013904223) >>> 0; return s / 4294967296; };
  }
  var pwRand = seedRand(426011);
  var POOL_UPPER = 'ABCDEFGHJKLMNPQRSTUVWXYZ';
  var POOL_LOWER = 'abcdefghijkmnpqrstuvwxyz';
  var POOL_DIGIT = '23456789';
  var POOL_SYMBOL = '!@#$%*?-';
  var POOL_ALL = POOL_UPPER + POOL_LOWER + POOL_DIGIT + POOL_SYMBOL;
  function makeFakePassword() {
    var len = 8 + Math.floor(pwRand() * 5);
    var out = '';
    for (var i = 0; i < len; i += 1) out += POOL_ALL.charAt(Math.floor(pwRand() * POOL_ALL.length));
    return out;
  }
  var FAKE_PW = makeFakePassword();
  input.value = FAKE_PW;

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

  var LABEL_SHOW = 'パスワードを表示';
  var LABEL_HIDE = 'パスワードを隠す';

  var reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;

  function buildOverlay(value) {
    overlay.textContent = '';
    for (var i = 0; i < value.length; i += 1) {
      var ch = document.createElement('span');
      ch.className = 'pem__ch';
      var delay = (i * CHAR_STAGGER_MS) + 'ms';
      var mask = document.createElement('span');
      mask.className = 'pem__mask';
      mask.style.transitionDelay = delay;
      mask.textContent = String.fromCharCode(8226);
      var real = document.createElement('span');
      real.className = 'pem__char';
      real.style.transitionDelay = delay;
      real.textContent = value.charAt(i);
      ch.appendChild(mask);
      ch.appendChild(real);
      overlay.appendChild(ch);
    }
  }
  buildOverlay(FAKE_PW);

  input.addEventListener('input', function () {
    buildOverlay(input.value);
  });

  var eyeProgress = 0;
  var eyeRaf = null;
  function paintEye(progress) {
    var eased = easeOutCubic(progress);
    var topY = 12 - 8 * eased;
    var botY = 12 + 8 * eased;
    lidTop.setAttribute('d', 'M2,12 Q12,' + topY + ' 22,12');
    lidBottom.setAttribute('d', 'M2,12 Q12,' + botY + ' 22,12');
    pupil.style.opacity = String(eased);
  }
  paintEye(eyeProgress);

  function animateEyeStep(ts) {
    if (animT0 === null) animT0 = ts;
    var elapsed = ts - animT0;
    var p = Math.min(1, elapsed / EYE_MORPH_MS);
    eyeProgress = animStart + (animTarget - animStart) * p;
    paintEye(eyeProgress);
    if (p < 1) { eyeRaf = requestAnimationFrame(animateEyeStep); }
    else { eyeRaf = null; eyeProgress = animTarget; paintEye(eyeProgress); }
  }
  var animT0 = null, animStart = 0, animTarget = 0;
  function animateEyeTo(target) {
    if (eyeRaf) { cancelAnimationFrame(eyeRaf); eyeRaf = null; }
    if (reduce) { eyeProgress = target; paintEye(eyeProgress); return; }
    animStart = eyeProgress;
    animTarget = target;
    animT0 = null;
    eyeRaf = requestAnimationFrame(animateEyeStep);
  }

  var revealed = false;
  function setRevealed(next) {
    revealed = next;
    input.type = revealed ? 'text' : 'password';
    root.classList.toggle('pem--revealed', revealed);
    toggle.setAttribute('aria-pressed', String(revealed));
    toggle.setAttribute('aria-label', revealed ? LABEL_HIDE : LABEL_SHOW);
    animateEyeTo(revealed ? 1 : 0);
  }

  toggle.addEventListener('click', function () {
    root.classList.remove('is-demo');
    setRevealed(!revealed);
  });

  form.addEventListener('submit', function (e) { e.preventDefault(); });

  if (reduce) { root.classList.remove('is-demo'); }

  function demoLoop() {
    if (reduce) return;
    setRevealed(true);
    setTimeout(function () { setRevealed(false); }, 900);
    setTimeout(demoLoop, 2000);
  }
  if (!reduce) { setTimeout(demoLoop, 200); }
})();

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

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

const EYE_MORPH_MS = 260;
const CHAR_STAGGER_MS = 28;
const LABEL_SHOW = "비밀번호 표시";
const LABEL_HIDE = "비밀번호 숨기기";

export default function PasswordRevealEyeIconMorph() {
  const rootRef = useRef(null) as unknown as Box<HTMLDivElement | null>;
  const formRef = useRef(null) as unknown as Box<HTMLFormElement | null>;
  const inputRef = useRef(null) as unknown as Box<HTMLInputElement | null>;
  const overlayRef = useRef(null) as unknown as Box<HTMLSpanElement | null>;
  const toggleRef = useRef(null) as unknown as Box<HTMLButtonElement | null>;
  const lidTopRef = useRef(null) as unknown as Box<SVGPathElement | null>;
  const lidBottomRef = useRef(null) as unknown as Box<SVGPathElement | null>;
  const pupilRef = useRef(null) as unknown as Box<SVGCircleElement | null>;

  useEffect(() => {
    const root = rootRef.current;
    const form = formRef.current;
    const input = inputRef.current;
    const overlay = overlayRef.current;
    const toggle = toggleRef.current;
    const lidTop = lidTopRef.current;
    const lidBottom = lidBottomRef.current;
    const pupil = pupilRef.current;
    if (!root || !form || !input || !overlay || !toggle || !lidTop || !lidBottom || !pupil) return;

    function seedRand(seed: number) {
      let s = seed >>> 0;
      return function () { s = (s * 1664525 + 1013904223) >>> 0; return s / 4294967296; };
    }
    const pwRand = seedRand(426012);
    const POOL_UPPER = "ABCDEFGHJKLMNPQRSTUVWXYZ";
    const POOL_LOWER = "abcdefghijkmnpqrstuvwxyz";
    const POOL_DIGIT = "23456789";
    const POOL_SYMBOL = "!@#$%*?-";
    const POOL_ALL = POOL_UPPER + POOL_LOWER + POOL_DIGIT + POOL_SYMBOL;
    function makeFakePassword() {
      const len = 8 + Math.floor(pwRand() * 5);
      let out = "";
      for (let i = 0; i < len; i += 1) out += POOL_ALL.charAt(Math.floor(pwRand() * POOL_ALL.length));
      return out;
    }
    const FAKE_PW = makeFakePassword();
    input.value = FAKE_PW;

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

    const reduce = window.matchMedia("(prefers-reduced-motion: reduce)").matches;

    function buildOverlay(value: string) {
      overlay!.textContent = "";
      for (let i = 0; i < value.length; i += 1) {
        const ch = document.createElement("span");
        ch.className = styles.ch;
        const delay = (i * CHAR_STAGGER_MS) + "ms";
        const mask = document.createElement("span");
        mask.className = styles.mask;
        mask.style.transitionDelay = delay;
        mask.textContent = String.fromCharCode(8226);
        const real = document.createElement("span");
        real.className = styles.char;
        real.style.transitionDelay = delay;
        real.textContent = value.charAt(i);
        ch.appendChild(mask);
        ch.appendChild(real);
        overlay!.appendChild(ch);
      }
    }
    buildOverlay(FAKE_PW);

    function onInput() { buildOverlay(input!.value); }
    input.addEventListener("input", onInput);

    let eyeProgress = 0;
    let eyeRaf = 0;
    function paintEye(progress: number) {
      const eased = easeOutCubic(progress);
      const topY = 12 - 8 * eased;
      const botY = 12 + 8 * eased;
      lidTop!.setAttribute("d", "M2,12 Q12," + topY + " 22,12");
      lidBottom!.setAttribute("d", "M2,12 Q12," + botY + " 22,12");
      pupil!.style.opacity = String(eased);
    }
    paintEye(eyeProgress);

    let animT0: number | null = null;
    let animStart = 0;
    let animTarget = 0;
    function animateEyeStep(ts: number) {
      if (animT0 === null) animT0 = ts;
      const elapsed = ts - animT0;
      const p = Math.min(1, elapsed / EYE_MORPH_MS);
      eyeProgress = animStart + (animTarget - animStart) * p;
      paintEye(eyeProgress);
      if (p < 1) { eyeRaf = requestAnimationFrame(animateEyeStep); }
      else { eyeRaf = 0; eyeProgress = animTarget; paintEye(eyeProgress); }
    }
    function animateEyeTo(target: number) {
      if (eyeRaf) { cancelAnimationFrame(eyeRaf); eyeRaf = 0; }
      if (reduce) { eyeProgress = target; paintEye(eyeProgress); return; }
      animStart = eyeProgress;
      animTarget = target;
      animT0 = null;
      eyeRaf = requestAnimationFrame(animateEyeStep);
    }

    let revealed = false;
    function setRevealed(next: boolean) {
      revealed = next;
      input!.type = revealed ? "text" : "password";
      root!.classList.toggle(styles["is-revealed"], revealed);
      toggle!.setAttribute("aria-pressed", String(revealed));
      toggle!.setAttribute("aria-label", revealed ? LABEL_HIDE : LABEL_SHOW);
      animateEyeTo(revealed ? 1 : 0);
    }

    function onToggleClick() {
      root!.classList.remove(styles["is-demo"]);
      setRevealed(!revealed);
    }
    toggle.addEventListener("click", onToggleClick);

    function onSubmit(e: Event) { e.preventDefault(); }
    form.addEventListener("submit", onSubmit);

    if (reduce) { root.classList.remove(styles["is-demo"]); }

    let loopTimer = 0;
    let closeTimer = 0;
    function demoLoop() {
      if (reduce) return;
      setRevealed(true);
      closeTimer = window.setTimeout(function () { setRevealed(false); }, 900);
      loopTimer = window.setTimeout(demoLoop, 2000);
    }
    let startTimer = 0;
    if (!reduce) { startTimer = window.setTimeout(demoLoop, 200); }

    return () => {
      input.removeEventListener("input", onInput);
      toggle.removeEventListener("click", onToggleClick);
      form.removeEventListener("submit", onSubmit);
      if (eyeRaf) cancelAnimationFrame(eyeRaf);
      window.clearTimeout(startTimer);
      window.clearTimeout(loopTimer);
      window.clearTimeout(closeTimer);
    };
  }, []);

  return (
    <main className={styles.stage}>
      <div ref={rootRef} className={`${styles.pem} ${styles["is-demo"]}`}>
        <form ref={formRef} className={styles.form} noValidate>
          <label className={styles.field}>
            <span className={styles.labelText}>비밀번호</span>
            <span className={styles.inputWrap}>
              <input
                ref={inputRef}
                className={styles.input}
                type="password"
                autoComplete="new-password"
                spellCheck={false}
                defaultValue=""
              />
              <span ref={overlayRef} className={styles.overlay} aria-hidden="true" />
              <button ref={toggleRef} className={styles.toggle} type="button" aria-pressed="false" aria-label="비밀번호 표시">
                <svg className={styles.eye} viewBox="0 0 24 24" width={22} height={22} aria-hidden="true">
                  <path ref={lidTopRef} d="M2,12 Q12,4 22,12" fill="none" stroke="currentColor" strokeWidth={2} strokeLinecap="round" />
                  <path ref={lidBottomRef} d="M2,12 Q12,20 22,12" fill="none" stroke="currentColor" strokeWidth={2} strokeLinecap="round" />
                  <circle ref={pupilRef} cx={12} cy={12} r={3.2} fill="currentColor" />
                </svg>
              </button>
            </span>
          </label>
        </form>
      </div>
    </main>
  );
}