09여러 코드가 인덱스 값을 따라 넘어가는 QR 캐러셀

<main class="stage">
<div class="mcc is-demo" id="mccRoot">
  <div class="mcc__badge" id="mccBadge">1 / 5</div>
  <button class="mcc__ctrl" id="mccCtrl" type="button">일시정지</button>
  <div class="mcc__canvas-wrap">
    <canvas class="mcc__canvas" id="mccCanvas" width="240" height="200"></canvas>
  </div>
</div>
</main>

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

// 핵심: 현재 위치와 각 코드 사이 원형 거리로 원근 스케일·투명도·좌우 이동량을
// 한 번에 계산한다 — 가까울수록 크고 진하게, 멀수록 작고 흐리게.

@include stage($stage-ink);

.mcc {
  position: relative;
  width: 100%;
  max-width: 424px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: $sp-3;
}

.mcc__badge {
  padding: $sp-1 $sp-3;
  border-radius: $r-pill;
  background: rgba(255, 247, 230, .08);
  color: $subject-cream;
  font-weight: 700;
  font-size: 11px;
  font-variant-numeric: tabular-nums;
}

.mcc__ctrl {
  position: absolute;
  top: 0;
  right: 0;
  border: 0;
  border-radius: $r-xs;
  padding: $sp-1 $sp-2;
  background: rgba(255, 247, 230, .12);
  color: $subject-cream;
  font-weight: 600;
  font-size: 10px;
  line-height: 1.4;
  cursor: pointer;
}
.mcc__ctrl:focus-visible { outline: 2px solid $subject-blue-light; outline-offset: 2px; }

.mcc__canvas-wrap {
  width: 100%;
  height: 220px;
  border-radius: $r-card;
  background: rgba(255, 255, 255, .04);
  display: grid;
  place-items: center;
  overflow: hidden;
}

.mcc__canvas {
  width: 100%;
  height: 100%;
  display: block;
}

@media (max-width: 340px) {
  .mcc { gap: $sp-1; }
  .mcc__badge { padding: $sp-1 $sp-2; font-size: 10px; }
  .mcc__canvas-wrap { height: 124px; }
}

@media (prefers-reduced-motion: reduce) {
  .mcc__canvas-wrap { background: rgba(255, 255, 255, .04); }
}

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);
}

.mcc {
  position: relative;
  width: 100%;
  max-width: 424px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
}

.mcc__badge {
  padding: 4px 12px;
  border-radius: 999px;
  background: rgba(255, 247, 230, 0.08);
  color: #fff7e6;
  font-weight: 700;
  font-size: 11px;
  font-variant-numeric: tabular-nums;
}

.mcc__ctrl {
  position: absolute;
  top: 0;
  right: 0;
  border: 0;
  border-radius: 4px;
  padding: 4px 8px;
  background: rgba(255, 247, 230, 0.12);
  color: #fff7e6;
  font-weight: 600;
  font-size: 10px;
  line-height: 1.4;
  cursor: pointer;
}

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

.mcc__canvas-wrap {
  width: 100%;
  height: 220px;
  border-radius: 16px;
  background: rgba(255, 255, 255, 0.04);
  display: grid;
  place-items: center;
  overflow: hidden;
}

.mcc__canvas {
  width: 100%;
  height: 100%;
  display: block;
}

@media (max-width: 340px) {
  .mcc {
    gap: 4px;
  }
  .mcc__badge {
    padding: 4px 8px;
    font-size: 10px;
  }
  .mcc__canvas-wrap {
    height: 124px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .mcc__canvas-wrap {
    background: rgba(255, 255, 255, 0.04);
  }
}

(function () {
  // MULTI_CODE_CAROUSEL_STEP_MS — 변형 1: 650 → 1000 으로 늘리면 코드가 더 느긋하게 넘어간다.
  var MULTI_CODE_CAROUSEL_STEP_MS = 650;
  var COUNT = 5;
  var LOOP_MS = MULTI_CODE_CAROUSEL_STEP_MS * COUNT;

  var canvas = document.getElementById('mccCanvas');
  var ctx = canvas.getContext('2d');
  var wrap = canvas.parentElement;
  var badge = document.getElementById('mccBadge');
  var ctrl = document.getElementById('mccCtrl');
  var root = document.getElementById('mccRoot');

  function seedRand(seed) {
    var s = seed >>> 0;
    return function () { s = (s * 1664525 + 1013904223) >>> 0; return s / 4294967296; };
  }
  var grids = [];
  for (var g = 0; g < COUNT; g += 1) {
    var rand = seedRand(407090 + g * 17);
    var dots = [];
    for (var y = 0; y < 7; y += 1) {
      for (var x = 0; x < 7; x += 1) {
        if (rand() < 0.44) dots.push({ x: x, y: y });
      }
    }
    grids.push(dots);
  }

  function easeInOut(t) { return t < 0.5 ? 2 * t * t : 1 - Math.pow(-2 * t + 2, 2) / 2; }

  // 계산된 시각 레이어: 캔버스 크기가 바뀌면 카드 간격·크기를 다시 잰다 —
  // 카드 이동·원근 스케일이 스테이지를 채우도록(278px 캡 없이 반응형).
  var dpr = 1, cw = 240, ch = 200, cy = 100, stepX = 74, boxBase = 60;
  function fit() {
    var r = wrap.getBoundingClientRect();
    dpr = window.devicePixelRatio || 1;
    cw = r.width; ch = r.height;
    canvas.width = Math.round(cw * dpr);
    canvas.height = Math.round(ch * dpr);
    ctx.setTransform(dpr, 0, 0, dpr, 0, 0);
    cy = ch / 2;
    stepX = cw * 0.31;
    boxBase = Math.min(cw * 0.24, ch * 0.5);
    draw(lastElapsed);
  }

  var lastElapsed = 0;
  function draw(elapsed) {
    lastElapsed = elapsed;
    ctx.clearRect(0, 0, cw, ch);

    var raw = elapsed / MULTI_CODE_CAROUSEL_STEP_MS;
    var index = Math.floor(raw) % COUNT;
    var localT = raw - Math.floor(raw);
    var eased = easeInOut(localT);
    var pos = index + eased;

    for (var i = 0; i < COUNT; i += 1) {
      // 계산 한 겹: 현재 위치와의 거리 → 원근 스케일·투명도·좌우 이동량을 함께 구한다.
      var diff = i - pos;
      while (diff > COUNT / 2) diff -= COUNT;
      while (diff < -COUNT / 2) diff += COUNT;
      var dist = Math.abs(diff);
      if (dist > 1.8) continue;
      var scale = Math.max(0.35, 1 - dist * 0.42);
      var alpha = Math.max(0, 1 - dist * 0.55);
      var cx = cw / 2 + diff * stepX;

      var box = boxBase * scale;
      ctx.globalAlpha = alpha;
      ctx.fillStyle = 'rgba(20,26,38,.92)';
      ctx.fillRect(cx - box / 2, cy - box / 2, box, box);
      var cell = box / 7;
      ctx.fillStyle = 'rgb(255,247,230)';
      grids[i].forEach(function (d) {
        var s = cell * 0.62;
        ctx.fillRect(cx - box / 2 + d.x * cell + (cell - s) / 2, cy - box / 2 + d.y * cell + (cell - s) / 2, s, s);
      });
    }
    ctx.globalAlpha = 1;

    badge.textContent = (index + 1) + ' / ' + COUNT;
  }

  var reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
  var playing = true;
  var elapsed = reduce ? 0 : 0;
  if (reduce) {
    playing = false;
    root.classList.remove('is-demo');
  }

  var lastTs = null;
  function tick(ts) {
    if (lastTs === null) lastTs = ts;
    var dt = ts - lastTs;
    lastTs = ts;
    if (playing) {
      elapsed += dt;
      if (elapsed >= LOOP_MS) elapsed -= LOOP_MS;
    }
    draw(elapsed);
    requestAnimationFrame(tick);
  }
  fit();
  window.addEventListener('resize', fit);
  draw(elapsed);
  requestAnimationFrame(tick);

  ctrl.addEventListener('click', function () {
    playing = !playing;
    ctrl.textContent = playing ? '일시정지' : '재생';
  });
  ctrl.addEventListener('keydown', function (e) {
    if ((e.key === 'r' || e.key === 'R') && !reduce) {
      elapsed = 0;
      playing = true;
      ctrl.textContent = '일시정지';
    }
  });
})();

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

export default function MultiCodeCarousel() {
  const rootRef = useRef<HTMLDivElement>(null);
  const canvasRef = useRef<HTMLCanvasElement>(null);
  const ctrlRef = useRef<HTMLButtonElement>(null);
  const [badge, setBadge] = useState("1 / 5");
  const [ctrlLabel, setCtrlLabel] = useState("일시정지");

  useEffect(() => {
    const root = rootRef.current;
    const canvas = canvasRef.current;
    const ctrl = ctrlRef.current;
    if (!root || !canvas || !ctrl) return;
    const ctx = canvas.getContext("2d");
    if (!ctx) return;

    // MULTI_CODE_CAROUSEL_STEP_MS — 변형 1: 650 → 1000 으로 늘리면 코드가 더 느긋하게 넘어간다.
    const MULTI_CODE_CAROUSEL_STEP_MS = 650;
    const COUNT = 5;
    const LOOP_MS = MULTI_CODE_CAROUSEL_STEP_MS * COUNT;
    const wrap = canvas.parentElement as HTMLElement;

    function seedRand(seed: number) {
      let s = seed >>> 0;
      return function () {
        s = (s * 1664525 + 1013904223) >>> 0;
        return s / 4294967296;
      };
    }
    const grids: { x: number; y: number }[][] = [];
    for (let g = 0; g < COUNT; g += 1) {
      const rand = seedRand(407090 + g * 17);
      const dots: { x: number; y: number }[] = [];
      for (let y = 0; y < 7; y += 1) {
        for (let x = 0; x < 7; x += 1) {
          if (rand() < 0.44) dots.push({ x, y });
        }
      }
      grids.push(dots);
    }

    function easeInOut(t: number) { return t < 0.5 ? 2 * t * t : 1 - Math.pow(-2 * t + 2, 2) / 2; }

    // 계산된 시각 레이어: 캔버스 크기가 바뀌면 카드 간격·크기를 다시 잰다 —
    // 카드 이동·원근 스케일이 스테이지를 채우도록(278px 캡 없이 반응형).
    let dpr = 1, cw = 240, ch = 200, cy = 100, stepX = 74, boxBase = 60;
    function fit() {
      const r = wrap.getBoundingClientRect();
      dpr = window.devicePixelRatio || 1;
      cw = r.width; ch = r.height;
      canvas!.width = Math.round(cw * dpr);
      canvas!.height = Math.round(ch * dpr);
      ctx!.setTransform(dpr, 0, 0, dpr, 0, 0);
      cy = ch / 2;
      stepX = cw * 0.31;
      boxBase = Math.min(cw * 0.24, ch * 0.5);
      draw(lastElapsed);
    }

    let lastElapsed = 0;
    function draw(elapsed: number) {
      lastElapsed = elapsed;
      ctx!.clearRect(0, 0, cw, ch);

      const raw = elapsed / MULTI_CODE_CAROUSEL_STEP_MS;
      const index = Math.floor(raw) % COUNT;
      const localT = raw - Math.floor(raw);
      const eased = easeInOut(localT);
      const pos = index + eased;

      for (let i = 0; i < COUNT; i += 1) {
        // 계산 한 겹: 현재 위치와의 거리 → 원근 스케일·투명도·좌우 이동량을 함께 구한다.
        let diff = i - pos;
        while (diff > COUNT / 2) diff -= COUNT;
        while (diff < -COUNT / 2) diff += COUNT;
        const dist = Math.abs(diff);
        if (dist > 1.8) continue;
        const scale = Math.max(0.35, 1 - dist * 0.42);
        const alpha = Math.max(0, 1 - dist * 0.55);
        const cx = cw / 2 + diff * stepX;

        const box = boxBase * scale;
        ctx!.globalAlpha = alpha;
        ctx!.fillStyle = "rgba(20,26,38,.92)";
        ctx!.fillRect(cx - box / 2, cy - box / 2, box, box);
        const cell = box / 7;
        ctx!.fillStyle = "rgb(255,247,230)";
        grids[i].forEach((d) => {
          const s = cell * 0.62;
          ctx!.fillRect(cx - box / 2 + d.x * cell + (cell - s) / 2, cy - box / 2 + d.y * cell + (cell - s) / 2, s, s);
        });
      }
      ctx!.globalAlpha = 1;

      setBadge((index + 1) + " / " + COUNT);
    }

    const reduce = window.matchMedia("(prefers-reduced-motion: reduce)").matches;
    let playing = true;
    let elapsed = 0;
    if (reduce) {
      playing = false;
      root.classList.remove("is-demo");
    }

    let lastTs: number | null = null;
    let raf = 0;
    function tick(ts: number) {
      if (lastTs === null) lastTs = ts;
      const dt = ts - lastTs;
      lastTs = ts;
      if (playing) {
        elapsed += dt;
        if (elapsed >= LOOP_MS) elapsed -= LOOP_MS;
      }
      draw(elapsed);
      raf = requestAnimationFrame(tick);
    }
    fit();
    window.addEventListener("resize", fit);
    draw(elapsed);
    raf = requestAnimationFrame(tick);

    function onClick() {
      playing = !playing;
      setCtrlLabel(playing ? "일시정지" : "재생");
    }
    function onKeydown(e: KeyboardEvent) {
      if ((e.key === "r" || e.key === "R") && !reduce) {
        elapsed = 0;
        playing = true;
        setCtrlLabel("일시정지");
      }
    }
    ctrl.addEventListener("click", onClick);
    ctrl.addEventListener("keydown", onKeydown);

    return () => {
      cancelAnimationFrame(raf);
      window.removeEventListener("resize", fit);
      ctrl.removeEventListener("click", onClick);
      ctrl.removeEventListener("keydown", onKeydown);
    };
  }, []);

  return (
    <main className={styles.stage}>
      <div className={`${styles.mcc} is-demo`} ref={rootRef}>
        <div className={styles.mcc__badge}>{badge}</div>
        <button className={styles.mcc__ctrl} type="button" ref={ctrlRef}>{ctrlLabel}</button>
        <div className={styles["mcc__canvas-wrap"]}>
          <canvas className={styles.mcc__canvas} ref={canvasRef} width={240} height={200} />
        </div>
      </div>
    </main>
  );
}