07Thumbnail to lightbox morph

<main class="stage">
  <div class="fl-frame fl-focal is-demo">
    <button class="fl-thumb" type="button"><span class="fl-thumb__photo"></span></button>
    <div class="fl-panel"><span class="fl-panel__photo"></span></div>
    <div class="fl-panel fl-panel--demo" aria-hidden="true"><span class="fl-panel__photo"></span></div>
  </div>
</main>

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

// ── 변수 3개 ──────────────────────────────────────────
$duration: $dur-enter;
$easing: $ease-spring;
$color: $subject-blue;

@include stage($stage-orange);

.fl-frame {
  position: relative;
  width: 260px;
  height: 165px;
}

.fl-thumb {
  position: absolute; left: 0; top: 0;
  width: 90px; height: 60px;
  border: 0; border-radius: $r-sm; overflow: hidden; cursor: pointer; padding: 0;
  box-shadow: $shadow-press;
  -webkit-tap-highlight-color: transparent;
}
.fl-thumb__photo {
  position: absolute; inset: 0;
  background:
    radial-gradient(40px circle at 35% 35%, rgba(255, 255, 255, .55), transparent 60%),
    linear-gradient(150deg, $color, $subject-ink);
}

// 최종(자연) 위치 — FLIP 의 Last. transform-origin 을 top left 로 둬야 translate·scale 계산이 맞는다
.fl-panel {
  position: absolute; left: 44px; top: 28px;
  width: 172px; height: 110px;
  border-radius: $r-sm; overflow: hidden;
  box-shadow: $shadow-raised;
  transform-origin: top left; // 규칙8: FLIP 계산 기준점
  opacity: 0; pointer-events: none;
}
.fl-panel.is-open { opacity: 1; pointer-events: auto; }
.fl-panel:not(.fl-panel--demo) { transition: transform $duration $easing, opacity $duration $easing; }

.fl-panel__photo {
  position: absolute; inset: 0;
  background:
    radial-gradient(70px circle at 35% 35%, rgba(255, 255, 255, .55), transparent 60%),
    linear-gradient(150deg, $color, $subject-ink);
}

// 데모 캡처: 클릭 없이 같은 First→Last 지오메트리를 keyframes 로 무한 재생하는 복제 패널
// First(썸네일: left 0 top 0 90×60) 를 Last(패널: left 44 top 28 172×110) 기준으로 환산한 상수
// deltaX = 0-44 = -44px · deltaY = 0-28 = -28px · deltaW = 90/172 ≈ .523 · deltaH = 60/110 ≈ .545
.fl-panel--demo { opacity: 0; }
.fl-frame.is-demo .fl-panel:not(.fl-panel--demo) { display: none; } // 캡처 중엔 실사용 패널을 숨겨 겹치지 않게
.fl-frame.is-demo .fl-panel--demo {
  animation: fl-flip $dur-loop $easing infinite;
}
@keyframes fl-flip {
  0%   { transform: translate(-44px, -28px) scale(.523, .545); opacity: 0; }
  8%   { opacity: 1; }
  45%  { transform: translate(0, 0) scale(1, 1); opacity: 1; }
  60%  { transform: translate(0, 0) scale(1, 1); opacity: 1; }
  92%  { opacity: 0; }
  100% { transform: translate(-44px, -28px) scale(.523, .545); opacity: 0; }
}

@media (prefers-reduced-motion: reduce) {
  .fl-panel { transition: none !important; }
  .fl-frame.is-demo .fl-panel--demo {
    animation: none !important; transform: translate(0, 0) scale(1, 1) !important; opacity: 1 !important;
  }
}

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);
}

.fl-frame {
  position: relative;
  width: 260px;
  height: 165px;
}

.fl-thumb {
  position: absolute;
  left: 0;
  top: 0;
  width: 90px;
  height: 60px;
  border: 0;
  border-radius: 8px;
  overflow: hidden;
  cursor: pointer;
  padding: 0;
  box-shadow: 0 6px 12px rgba(23, 20, 26, 0.32);
  -webkit-tap-highlight-color: transparent;
}

.fl-thumb__photo {
  position: absolute;
  inset: 0;
  background: radial-gradient(40px circle at 35% 35%, rgba(255, 255, 255, 0.55), transparent 60%), linear-gradient(150deg, #2f6df6, #17141a);
}

.fl-panel {
  position: absolute;
  left: 44px;
  top: 28px;
  width: 172px;
  height: 110px;
  border-radius: 8px;
  overflow: hidden;
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
  transform-origin: top left;
  opacity: 0;
  pointer-events: none;
}

.fl-panel.is-open {
  opacity: 1;
  pointer-events: auto;
}

.fl-panel:not(.fl-panel--demo) {
  transition: transform 600ms cubic-bezier(0.2, 0.8, 0.2, 1), opacity 600ms cubic-bezier(0.2, 0.8, 0.2, 1);
}

.fl-panel__photo {
  position: absolute;
  inset: 0;
  background: radial-gradient(70px circle at 35% 35%, rgba(255, 255, 255, 0.55), transparent 60%), linear-gradient(150deg, #2f6df6, #17141a);
}

.fl-panel--demo {
  opacity: 0;
}

.fl-frame.is-demo .fl-panel:not(.fl-panel--demo) {
  display: none;
}

.fl-frame.is-demo .fl-panel--demo {
  animation: fl-flip 2s cubic-bezier(0.2, 0.8, 0.2, 1) infinite;
}

@keyframes fl-flip {
  0% {
    transform: translate(-44px, -28px) scale(0.523, 0.545);
    opacity: 0;
  }
  8% {
    opacity: 1;
  }
  45% {
    transform: translate(0, 0) scale(1, 1);
    opacity: 1;
  }
  60% {
    transform: translate(0, 0) scale(1, 1);
    opacity: 1;
  }
  92% {
    opacity: 0;
  }
  100% {
    transform: translate(-44px, -28px) scale(0.523, 0.545);
    opacity: 0;
  }
}
@media (prefers-reduced-motion: reduce) {
  .fl-panel {
    transition: none !important;
  }
  .fl-frame.is-demo .fl-panel--demo {
    animation: none !important;
    transform: translate(0, 0) scale(1, 1) !important;
    opacity: 1 !important;
  }
}

var thumb = document.querySelector('.fl-thumb'), panel = document.querySelector('.fl-panel'), frame = document.querySelector('.fl-frame');
thumb.addEventListener('click', function () {
  frame.classList.remove('is-demo');
  var t = thumb.getBoundingClientRect(), p = panel.getBoundingClientRect();
  panel.style.transform = 'translate(' + (t.left - p.left) + 'px,' + (t.top - p.top) + 'px) scale(' + (t.width / p.width) + ',' + (t.height / p.height) + ')';
  panel.classList.add('is-open');
  requestAnimationFrame(function () { panel.style.transform = 'translate(0,0) scale(1,1)'; });
});
panel.addEventListener('click', function () { panel.classList.remove('is-open'); panel.style.transform = ''; });

import { useRef, useState } from "react";
import styles from "./ThumbnailLightboxMorph.module.scss";

export interface ThumbnailLightboxMorphProps {
  duration?: string;
  easing?: string;
  color?: string;
}

export default function ThumbnailLightboxMorph({
  duration = "600ms",
  easing = "cubic-bezier(.2, .8, .2, 1)",
}: ThumbnailLightboxMorphProps) {
  const thumbRef = useRef<HTMLButtonElement>(null);
  const panelRef = useRef<HTMLDivElement>(null);
  const [open, setOpen] = useState(false);

  function openFlip() {
    const t = thumbRef.current?.getBoundingClientRect();
    const p = panelRef.current?.getBoundingClientRect();
    if (!t || !p || !panelRef.current) return;
    panelRef.current.style.transform = `translate(${t.left - p.left}px,${t.top - p.top}px) scale(${t.width / p.width},${t.height / p.height})`;
    setOpen(true);
    requestAnimationFrame(() => {
      if (panelRef.current) panelRef.current.style.transform = "translate(0,0) scale(1,1)";
    });
  }
  function closeFlip() {
    setOpen(false);
    if (panelRef.current) panelRef.current.style.transform = "";
  }

  return (
    <div className={styles.frame} style={{ transitionDuration: duration, transitionTimingFunction: easing }}>
      <button ref={thumbRef} className={styles.thumb} type="button" onClick={openFlip}>
        <span className={styles.thumbPhoto} />
      </button>
      <div
        ref={panelRef}
        className={`${styles.panel} ${open ? styles.isOpen : ""}`}
        style={{ transitionDuration: duration, transitionTimingFunction: easing }}
        onClick={closeFlip}
      >
        <span className={styles.panelPhoto} />
      </div>
    </div>
  );
}