07Heart pulse

<main class="stage">
  <button class="iconbtn is-demo" type="button" aria-pressed="false" aria-label="Thích">
    <span class="iconbtn__stack">
      <svg class="ic ic--outline" viewBox="0 0 24 24" width="26" height="26" aria-hidden="true">
        <path d="M12 20.2s-7.3-4.5-9.5-8.9C.9 7.9 2.6 4.6 5.9 4.1c2-.3 3.8.6 4.9 2.2 1-1.6 2.9-2.5 4.9-2.2 3.3.5 5 3.8 3.4 7.2-2.2 4.4-9.1 8.9-9.1 8.9z" fill="none" stroke="currentColor" stroke-width="1.7"/>
      </svg>
      <svg class="ic ic--fill" viewBox="0 0 24 24" width="26" height="26" aria-hidden="true">
        <path d="M12 20.2s-7.3-4.5-9.5-8.9C.9 7.9 2.6 4.6 5.9 4.1c2-.3 3.8.6 4.9 2.2 1-1.6 2.9-2.5 4.9-2.2 3.3.5 5 3.8 3.4 7.2-2.2 4.4-9.1 8.9-9.1 8.9z"/>
      </svg>
      <svg class="fx" viewBox="0 0 24 24" width="26" height="26" aria-hidden="true">
        <circle class="fx__spark" r=".9" cx="12" cy="12"/>
        <circle class="fx__bit" r=".5" cx="12" cy="6" style="--dx:0px;--dy:-2.6px"/>
        <circle class="fx__bit" r=".5" cx="12" cy="6" style="--dx:2.4px;--dy:-1.2px"/>
        <circle class="fx__bit" r=".5" cx="12" cy="6" style="--dx:-2.4px;--dy:-1.2px"/>
        <circle class="fx__bit" r=".45" cx="4" cy="8" style="--dx:-2.6px;--dy:-1px"/>
        <circle class="fx__bit" r=".45" cx="20" cy="8" style="--dx:2.6px;--dy:-1px"/>
        <circle class="fx__bit" r=".45" cx="12" cy="20" style="--dx:0px;--dy:2.6px"/>
      </svg>
    </span>
  </button>
</main>

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

// ── 변수 3개 ──────────────────────────────
$duration: $dur-quick;  // 220ms — 튕기는 시간
$easing: $ease-pop;
$color: $subject-cream;

// ── 데모 무대 ───────────────────────────────
@include stage($stage-orange);

.iconbtn {
  border: 0; background: none; cursor: pointer; color: $color;
  border-radius: $r-sm;
  width: clamp(52px, 14vw, 64px); height: clamp(52px, 14vw, 64px);
  display: grid; place-items: center;
  -webkit-tap-highlight-color: transparent;
}
.iconbtn:focus-visible { outline: 2px solid $color; outline-offset: 3px; }
.iconbtn__stack { display: grid; place-items: center; width: 100%; height: 100%; }

.ic {
  grid-area: 1 / 1;
  transition: opacity $duration $easing, transform $duration $easing;
  transform-box: fill-box; transform-origin: 50% 50%;
}
.ic--outline { opacity: 1; }
.ic--fill    { fill: $color; opacity: 0; }
.iconbtn[aria-pressed="true"] .ic--outline { opacity: 0; }
.iconbtn[aria-pressed="true"] .ic--fill    { opacity: 1; transform: scale(1); }

.iconbtn.is-demo .ic--outline { animation: outline-loop $dur-loop $easing infinite; }
.iconbtn.is-demo .ic--fill    { animation: fill-loop $dur-loop $easing infinite; }

@keyframes outline-loop { 0%, 15% { opacity: 1; transform: scale(1); } 30% { transform: scale(1.3); } 40%, 60% { opacity: 0; } 85%, 100% { opacity: 1; transform: scale(1); } }
@keyframes fill-loop    { 0%, 15% { opacity: 0; transform: scale(1); } 30% { transform: scale(1.3); } 40%, 60% { opacity: 1; } 85%, 100% { opacity: 0; transform: scale(1); } }

// ── 한 겹: 채워지는 순간 가장자리 입자 + 중앙 스파크 ─────────
// 아이콘과 같은 칸에 겹쳐 놓은 효과 레이어 — 레이아웃에는 영향이 없다
.fx {
  grid-area: 1 / 1;
  fill: currentColor;
  pointer-events: none;
}

// 중앙 스파크 — 하트가 차오르는 순간 밝게 점멸
.fx__spark {
  opacity: 0;
  transform-box: fill-box;
  transform-origin: 50% 50%;
  filter: drop-shadow(0 0 1px $color);       // 미광
}
@keyframes spark-pop {
  0%   { opacity: .95; transform: scale(1.8); }
  60%  { opacity: .4;  transform: scale(.8); }
  100% { opacity: 0;   transform: scale(.3); }
}

// 하트 가장자리에서 바깥으로 흩어지는 입자 — JS 가 좌표·방향을 계산해 넣는다
.fx__bit {
  opacity: 0;
  transform: translate(0, 0);
}
@keyframes bit-fly {
  0%   { opacity: .9; transform: translate(0, 0) scale(1); }
  100% { opacity: 0;  transform: translate(var(--dx), var(--dy)) scale(.3); }
}

@media (prefers-reduced-motion: reduce) {
  .iconbtn.is-demo .ic--outline, .iconbtn.is-demo .ic--fill { animation: none; }
  .ic { transition: none; }
  .fx { display: 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);
}

.iconbtn {
  border: 0;
  background: none;
  cursor: pointer;
  color: #fff7e6;
  border-radius: 8px;
  width: clamp(52px, 14vw, 64px);
  height: clamp(52px, 14vw, 64px);
  display: grid;
  place-items: center;
  -webkit-tap-highlight-color: transparent;
}

.iconbtn:focus-visible {
  outline: 2px solid #fff7e6;
  outline-offset: 3px;
}

.iconbtn__stack {
  display: grid;
  place-items: center;
  width: 100%;
  height: 100%;
}

.ic {
  grid-area: 1/1;
  transition: opacity 220ms cubic-bezier(0.2, 1.4, 0.4, 1), transform 220ms cubic-bezier(0.2, 1.4, 0.4, 1);
  transform-box: fill-box;
  transform-origin: 50% 50%;
}

.ic--outline {
  opacity: 1;
}

.ic--fill {
  fill: #fff7e6;
  opacity: 0;
}

.iconbtn[aria-pressed=true] .ic--outline {
  opacity: 0;
}

.iconbtn[aria-pressed=true] .ic--fill {
  opacity: 1;
  transform: scale(1);
}

.iconbtn.is-demo .ic--outline {
  animation: outline-loop 2s cubic-bezier(0.2, 1.4, 0.4, 1) infinite;
}

.iconbtn.is-demo .ic--fill {
  animation: fill-loop 2s cubic-bezier(0.2, 1.4, 0.4, 1) infinite;
}

@keyframes outline-loop {
  0%, 15% {
    opacity: 1;
    transform: scale(1);
  }
  30% {
    transform: scale(1.3);
  }
  40%, 60% {
    opacity: 0;
  }
  85%, 100% {
    opacity: 1;
    transform: scale(1);
  }
}
@keyframes fill-loop {
  0%, 15% {
    opacity: 0;
    transform: scale(1);
  }
  30% {
    transform: scale(1.3);
  }
  40%, 60% {
    opacity: 1;
  }
  85%, 100% {
    opacity: 0;
    transform: scale(1);
  }
}
.fx {
  grid-area: 1/1;
  fill: currentColor;
  pointer-events: none;
}

.fx__spark {
  opacity: 0;
  transform-box: fill-box;
  transform-origin: 50% 50%;
  filter: drop-shadow(0 0 1px #fff7e6);
}

@keyframes spark-pop {
  0% {
    opacity: 0.95;
    transform: scale(1.8);
  }
  60% {
    opacity: 0.4;
    transform: scale(0.8);
  }
  100% {
    opacity: 0;
    transform: scale(0.3);
  }
}
.fx__bit {
  opacity: 0;
  transform: translate(0, 0);
}

@keyframes bit-fly {
  0% {
    opacity: 0.9;
    transform: translate(0, 0) scale(1);
  }
  100% {
    opacity: 0;
    transform: translate(var(--dx), var(--dy)) scale(0.3);
  }
}
@media (prefers-reduced-motion: reduce) {
  .iconbtn.is-demo .ic--outline, .iconbtn.is-demo .ic--fill {
    animation: none;
  }
  .ic {
    transition: none;
  }
  .fx {
    display: none;
  }
}

document.querySelectorAll(".iconbtn").forEach(function (b) {
  b.addEventListener("click", function () {
    b.classList.remove("is-demo");
    var on = b.getAttribute("aria-pressed") === "true";
    b.setAttribute("aria-pressed", String(!on));
  });
});

// ── 한 겹: 하트 채워지는 순간 가장자리 입자 폭발 + 중앙 스파크 ──────
// 펄스는 짧은 사건이다 — 01 처럼 펜 끝을 쫓는 대신, '채움 하트가 나타나는 프레임'을
// getComputedStyle opacity 실측으로 감지해 그 순간 하트 가장자리에서 입자를 터뜨린다.
// 입자 좌표는 fill 하트 path 를 getTotalLength/getPointAtLength 로 6 점 샘플링해 얻고,
// 방향은 도심(12,12)에서 바깥으로 — 하트가 '탁' 차오르는 물성을 흉내 낸다.
(function () {
  var btn = document.querySelector('.iconbtn');
  if (!btn) return;
  var fx = btn.querySelector('.fx');
  var fill = btn.querySelector('.ic--fill path');
  if (!fx || !fill || !fill.getTotalLength) return;
  var spark = fx.querySelector('.fx__spark');
  var bits = [].slice.call(fx.querySelectorAll('.fx__bit'));
  var reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
  if (reduce || !spark) { fx.style.display = 'none'; return; }

  var L = fill.getTotalLength();
  var CX = 12, CY = 12;
  // 입자 하나를 하트 가장자리 임의 점에 재배치하고 바깥 방향으로 흩어지게 한다
  function seed(b) {
    var p = fill.getPointAtLength(Math.random() * L);
    b.setAttribute('cx', p.x);
    b.setAttribute('cy', p.y);
    var dx = p.x - CX, dy = p.y - CY;
    var len = Math.sqrt(dx * dx + dy * dy) || 1;
    var sp = .45 + Math.random() * .55;
    b.style.setProperty('--dx', (dx / len * sp * 6.5).toFixed(2) + 'px');
    b.style.setProperty('--dy', (dy / len * sp * 6.5).toFixed(2) + 'px');
    b.style.animation = 'none';
    void b.getBoundingClientRect();
    b.style.animation = '';
    b.style.animationName = 'bit-fly';
  }
  function burst() {
    spark.style.animation = 'none';
    void spark.getBoundingClientRect();
    spark.style.animation = '';
    spark.style.animationName = 'spark-pop';
    bits.forEach(function (b) { seed(b); });
  }

  var prevO = null, lastBurst = 0;
  function frame(t) {
    // 채움 하트가 나타나는 프레임 = opacity 가 0→1 로 오르는 중.
    // 데모 루프의 상승 구간은 500ms — 문턱을 그보다 길게 잡아 한 번만 터진다
    var o = parseFloat(getComputedStyle(fill.closest('.ic--fill')).opacity);
    if (prevO !== null && o - prevO > .02 && t - lastBurst > 600) {
      lastBurst = t;
      burst();
    }
    prevO = o;
    requestAnimationFrame(frame);
  }
  requestAnimationFrame(frame);
})();

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

export type HeartPulseProps = {
  /** 튕기는 시간, ms */
  duration?: number;
  easing?: string;
  color?: string;
  defaultLiked?: boolean;
  onChange?: (liked: boolean) => void;
};

type Vars = CSSProperties & { "--duration"?: string; "--easing"?: string; "--color"?: string };
const HEART = "M12 20.2s-7.3-4.5-9.5-8.9C.9 7.9 2.6 4.6 5.9 4.1c2-.3 3.8.6 4.9 2.2 1-1.6 2.9-2.5 4.9-2.2 3.3.5 5 3.8 3.4 7.2-2.2 4.4-9.1 8.9-9.1 8.9z";
const BIT_COUNT = 6;
const CX = 12, CY = 12;

export default function HeartPulse({
  duration = 220,
  easing = "cubic-bezier(.2,1.4,.4,1)",
  color = "#fff7e6",
  defaultLiked = false,
  onChange,
}: HeartPulseProps) {
  const [liked, setLiked] = useState(defaultLiked);
  const pathRef = useRef<SVGPathElement>(null);
  const sparkRef = useRef<SVGCircleElement>(null);
  const bitRefs = useRef<Array<SVGCircleElement | null>>([]) as unknown as { current: Array<SVGCircleElement | null> };
  const burstRef = useRef<(() => void) | null>(null);
  const vars: Vars = { "--duration": `${duration}ms`, "--easing": easing, "--color": color };

  // 한 겹: 좋아요 순간 하트 가장자리 입자 폭발 + 중앙 스파크 (vanilla 데모와 동일 계산).
  // 하트 path 를 getTotalLength/getPointAtLength 로 샘플링해 입자를 가장자리에 뿌리고
  // 도심에서 바깥 방향으로 흩어지게 한다.
  useEffect(() => {
    const heart = pathRef.current, spark = sparkRef.current;
    if (!heart || !spark || !heart.getTotalLength) return;
    if (window.matchMedia("(prefers-reduced-motion: reduce)").matches) return;
    const bits = bitRefs.current.filter(Boolean) as SVGCircleElement[];
    const L = heart.getTotalLength();
    const restart = (el: SVGElement) => {
      el.style.animation = "none";
      void el.getBoundingClientRect();
      el.style.animation = "";
    };
    burstRef.current = () => {
      restart(spark);
      bits.forEach((b) => {
        const p = heart.getPointAtLength(Math.random() * L);
        b.setAttribute("cx", p.x.toFixed(2));
        b.setAttribute("cy", p.y.toFixed(2));
        const dx = p.x - CX, dy = p.y - CY;
        const len = Math.sqrt(dx * dx + dy * dy) || 1;
        const sp = 0.45 + Math.random() * 0.55;
        b.style.setProperty("--dx", ((dx / len) * sp * 6.5).toFixed(2) + "px");
        b.style.setProperty("--dy", ((dy / len) * sp * 6.5).toFixed(2) + "px");
        restart(b);
      });
    };
    return () => { burstRef.current = null; };
  }, []);

  return (
    <button
      type="button"
      className={styles.iconbtn}
      style={vars}
      aria-pressed={liked}
      aria-label="좋아요"
      onClick={() => {
        setLiked((v) => !v);
        burstRef.current?.();
        onChange?.(!liked);
      }}
    >
      <span className={styles.iconbtn__stack}>
        <svg className={`${styles.ic} ${liked ? styles["ic--hidden"] : ""}`} viewBox="0 0 24 24" width="26" height="26" aria-hidden="true">
          <path d={HEART} fill="none" stroke="currentColor" strokeWidth={1.7} />
        </svg>
        <svg className={`${styles.ic} ${styles["ic--fill"]} ${liked ? "" : styles["ic--hidden"]}`} viewBox="0 0 24 24" width="26" height="26" aria-hidden="true">
          {/* pathRef — 입자 좌표 샘플링용 원본 경로. getTotalLength 는 경로 기하학만 보므로
              스케일 애니메이션·투명도와 무관하게 항상 같은 하트 좌표를 돌려준다 */}
          <path ref={pathRef} d={HEART} />
        </svg>
        <svg className={styles.fx} viewBox="0 0 24 24" width="26" height="26" aria-hidden="true">
          <circle ref={sparkRef} className={styles["fx__spark"]} r={0.9} cx={12} cy={12} />
          {Array.from({ length: BIT_COUNT }, (_, i) => (
            <circle
              key={i}
              ref={(el: SVGCircleElement | null) => { bitRefs.current[i] = el; }}
              className={styles["fx__bit"]}
              r={i < 3 ? 0.5 : 0.45}
              cx={12}
              cy={6}
              style={{ "--dx": "0px", "--dy": "-2.6px" } as CSSProperties}
            />
          ))}
        </svg>
      </span>
    </button>
  );
}