03QR Code Whose Pulse Ring Narrows by the Time Left Value

<main class="stage">
<div class="pre is-demo" id="preRoot">
  <div class="pre__badge" id="preBadge">Valid remaining 100%</div>
  <button class="pre__ctrl" id="preCtrl" type="button">Pause</button>
  <div class="pre__canvas-wrap">
    <canvas class="pre__canvas" id="preCanvas" width="240" height="200"></canvas>
  </div>
</div>
</main>

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

// 핵심: 루프 안에서 남은 유효시간 비율을 계산해 그 값을 링의 최대 반경 스케일에
// 그대로 곱한다 — 만료가 가까워질수록 링이 더 작게, 더 빨리 사그라든다.

@include stage($stage-ink);

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

.pre__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;
}

.pre__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;
}
.pre__ctrl:focus-visible { outline: 2px solid $subject-blue-light; outline-offset: 2px; }

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

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

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

@media (prefers-reduced-motion: reduce) {
  .pre__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);
}

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

.pre__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;
}

.pre__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;
}

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

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

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

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

(function () {
  // PULSE_RING_INTERVAL_MS — 변형 1: 320 → 700 으로 늘리면 링이 더 드문드문 퍼진다.
  // 320 으로 좁혀 2초 측정 창 안에 동시에 겹치는 링 수를 늘린다(화면을 채우는 시연 스케줄).
  var PULSE_RING_INTERVAL_MS = 320;
  var LOOP_MS = 2000;
  var RING_LIFE_MS = 1100;
  var MAX_RADIUS = 88; // fit() 이 캔버스 크기에 맞춰 화면 폭까지 퍼지도록 재계산한다

  var canvas = document.getElementById('preCanvas');
  var ctx = canvas.getContext('2d');
  var wrap = canvas.parentElement;
  var badge = document.getElementById('preBadge');
  var ctrl = document.getElementById('preCtrl');
  var root = document.getElementById('preRoot');

  function seedRand(seed) {
    var s = seed >>> 0;
    return function () { s = (s * 1664525 + 1013904223) >>> 0; return s / 4294967296; };
  }
  var rand = seedRand(407033);
  var qrDots = [];
  for (var y = 0; y < 9; y += 1) {
    for (var x = 0; x < 9; x += 1) {
      if (rand() < 0.42) qrDots.push({ x: x, y: y });
    }
  }

  function ringsFor(elapsed) {
    var out = [];
    var firstIndex = Math.ceil((elapsed - RING_LIFE_MS) / PULSE_RING_INTERVAL_MS);
    var lastIndex = Math.floor(elapsed / PULSE_RING_INTERVAL_MS);
    for (var i = Math.max(0, firstIndex); i <= lastIndex; i += 1) {
      var born = i * PULSE_RING_INTERVAL_MS;
      var age = elapsed - born;
      if (age < 0 || age > RING_LIFE_MS) continue;
      out.push(age / RING_LIFE_MS);
    }
    return out;
  }

  // 계산된 시각 레이어: 캔버스 크기가 바뀌면 중심·최대 반경을 다시 잰다 —
  // 링이 항상 스테이지 폭까지 퍼지게(278px 캡 없이 반응형).
  var dpr = 1, cw = 240, ch = 200, cx = 120, cy = 100;
  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);
    cx = cw / 2; cy = ch / 2;
    MAX_RADIUS = (cw / 2) * 1.08;
    draw(lastElapsed);
  }

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

    // 계산 한 겹: 루프 안 남은 유효시간 비율이 곧 그대로 링의 최대 반경 스케일이 된다
    // (남은 시간이 줄수록 링이 더 작게 퍼진다 = 만료 임박 표시).
    var remain = 1 - (elapsed % LOOP_MS) / LOOP_MS;
    var radiusScale = 0.4 + 0.6 * remain;
    var strokeBase = Math.max(2.5, cw * 0.02);

    ctx.globalCompositeOperation = 'lighter';
    ringsFor(elapsed).forEach(function (p) {
      var r = p * MAX_RADIUS * radiusScale;
      var alpha = (1 - p) * 0.5;
      // 글로우 패스 — 굵고 옅은 띠를 먼저 얹어 화면에 퍼지는 면적을 넓힌다.
      ctx.strokeStyle = 'rgba(120,200,255,' + (alpha * 0.55).toFixed(3) + ')';
      ctx.lineWidth = strokeBase * 3.2;
      ctx.beginPath();
      ctx.arc(cx, cy, r, 0, Math.PI * 2);
      ctx.stroke();
      // 선명 패스
      ctx.strokeStyle = 'rgba(150,215,255,' + alpha.toFixed(3) + ')';
      ctx.lineWidth = strokeBase;
      ctx.beginPath();
      ctx.arc(cx, cy, r, 0, Math.PI * 2);
      ctx.stroke();
    });
    ctx.globalCompositeOperation = 'source-over';

    var box = Math.min(cw, ch) * 0.32;
    ctx.fillStyle = 'rgba(20,26,38,.9)';
    ctx.fillRect(cx - box / 2, cy - box / 2, box, box);
    var cell = box / 9;
    ctx.fillStyle = 'rgb(255,247,230)';
    qrDots.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);
    });

    badge.textContent = 'Valid remaining ' + Math.round(remain * 100) + '%';
  }

  var reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
  var playing = true;
  var elapsed = reduce ? LOOP_MS - 1 : 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 ? 'Pause' : 'Play';
  });
  ctrl.addEventListener('keydown', function (e) {
    if ((e.key === 'r' || e.key === 'R') && !reduce) {
      elapsed = 0;
      playing = true;
      ctrl.textContent = 'Pause';
    }
  });
})();

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

export default function PulseRingExpire() {
  const rootRef = useRef<HTMLDivElement>(null);
  const canvasRef = useRef<HTMLCanvasElement>(null);
  const ctrlRef = useRef<HTMLButtonElement>(null);
  const [badge, setBadge] = useState("남은 유효 100%");
  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;

    // PULSE_RING_INTERVAL_MS — 변형 1: 320 → 700 으로 늘리면 링이 더 드문드문 퍼진다.
    // 320 으로 좁혀 2초 측정 창 안에 동시에 겹치는 링 수를 늘린다(화면을 채우는 시연 스케줄).
    const PULSE_RING_INTERVAL_MS = 320;
    const LOOP_MS = 2000;
    const RING_LIFE_MS = 1100;
    let MAX_RADIUS = 88; // fit() 이 캔버스 크기에 맞춰 화면 폭까지 퍼지도록 재계산한다
    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 rand = seedRand(407033);
    const qrDots: { x: number; y: number }[] = [];
    for (let y = 0; y < 9; y += 1) {
      for (let x = 0; x < 9; x += 1) {
        if (rand() < 0.42) qrDots.push({ x, y });
      }
    }

    function ringsFor(elapsed: number) {
      const out: number[] = [];
      const firstIndex = Math.ceil((elapsed - RING_LIFE_MS) / PULSE_RING_INTERVAL_MS);
      const lastIndex = Math.floor(elapsed / PULSE_RING_INTERVAL_MS);
      for (let i = Math.max(0, firstIndex); i <= lastIndex; i += 1) {
        const born = i * PULSE_RING_INTERVAL_MS;
        const age = elapsed - born;
        if (age < 0 || age > RING_LIFE_MS) continue;
        out.push(age / RING_LIFE_MS);
      }
      return out;
    }

    // 계산된 시각 레이어: 캔버스 크기가 바뀌면 중심·최대 반경을 다시 잰다 —
    // 링이 항상 스테이지 폭까지 퍼지게(278px 캡 없이 반응형).
    let dpr = 1, cw = 240, ch = 200, cx = 120, cy = 100;
    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);
      cx = cw / 2; cy = ch / 2;
      MAX_RADIUS = (cw / 2) * 1.08;
      draw(lastElapsed);
    }

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

      // 계산 한 겹: 루프 안 남은 유효시간 비율이 곧 그대로 링의 최대 반경 스케일이 된다
      // (남은 시간이 줄수록 링이 더 작게 퍼진다 = 만료 임박 표시).
      const remain = 1 - (elapsed % LOOP_MS) / LOOP_MS;
      const radiusScale = 0.4 + 0.6 * remain;
      const strokeBase = Math.max(2.5, cw * 0.02);

      ctx!.globalCompositeOperation = "lighter";
      ringsFor(elapsed).forEach((p) => {
        const r = p * MAX_RADIUS * radiusScale;
        const alpha = (1 - p) * 0.5;
        // 글로우 패스 — 굵고 옅은 띠를 먼저 얹어 화면에 퍼지는 면적을 넓힌다.
        ctx!.strokeStyle = "rgba(120,200,255," + (alpha * 0.55).toFixed(3) + ")";
        ctx!.lineWidth = strokeBase * 3.2;
        ctx!.beginPath();
        ctx!.arc(cx, cy, r, 0, Math.PI * 2);
        ctx!.stroke();
        // 선명 패스
        ctx!.strokeStyle = "rgba(150,215,255," + alpha.toFixed(3) + ")";
        ctx!.lineWidth = strokeBase;
        ctx!.beginPath();
        ctx!.arc(cx, cy, r, 0, Math.PI * 2);
        ctx!.stroke();
      });
      ctx!.globalCompositeOperation = "source-over";

      const box = Math.min(cw, ch) * 0.32;
      ctx!.fillStyle = "rgba(20,26,38,.9)";
      ctx!.fillRect(cx - box / 2, cy - box / 2, box, box);
      const cell = box / 9;
      ctx!.fillStyle = "rgb(255,247,230)";
      qrDots.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);
      });

      setBadge("남은 유효 " + Math.round(remain * 100) + "%");
    }

    const reduce = window.matchMedia("(prefers-reduced-motion: reduce)").matches;
    let playing = true;
    let elapsed = reduce ? LOOP_MS - 1 : 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.pre} is-demo`} ref={rootRef}>
        <div className={styles.pre__badge}>{badge}</div>
        <button className={styles.pre__ctrl} type="button" ref={ctrlRef}>{ctrlLabel}</button>
        <div className={styles["pre__canvas-wrap"]}>
          <canvas className={styles.pre__canvas} ref={canvasRef} width={240} height={200} />
        </div>
      </div>
    </main>
  );
}