06Charge-hold-release toggle — a value slowly fills while held and empties all at once on release

<main class="stage">
<div class="gb is-demo" id="gb">
  <div class="gb__head">
    <span class="gb__label">Charge Attack</span>
    <span class="gb__value" id="gbValue">0%</span>
  </div>
  <div class="gb__track" role="progressbar" aria-label="Charge" aria-valuemin="0" aria-valuemax="100" aria-valuenow="0" id="gbTrack">
    <div class="gb__fill" id="gbFill"></div>
    <div class="gb__burst" id="gbBurst"></div>
  </div>
  <button type="button" class="gb__hit" id="gbCharge">Hold to Charge</button>
</div>
</main>

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

// 계산 겹: index.html burstAt() 이 감쇠 코사인 진동(스프링 방정식)으로 방출 순간의
// 링 크기·투명도를 매 프레임 계산한다 — 손을 떼는 순간 값은 즉시 0, 링만 스프링으로 남는다.
@include stage($stage-yellow);

.gb { width: 100%; max-width: 260px; background: $subject-cream; border-radius: $r-card; padding: $sp-5; box-shadow: $shadow-raised; box-sizing: border-box; }
.gb__head { display: flex; justify-content: space-between; align-items: baseline; margin-bottom: $sp-3; }
.gb__label { font-size: 12px; font-weight: 700; letter-spacing: .04em; color: rgba($subject-ink, .72); text-transform: uppercase; }
.gb__value { font-size: 15px; font-weight: 700; color: $subject-ink; }

.gb__track { position: relative; height: 18px; border-radius: $r-pill; background: rgba($subject-ink, .1); overflow: visible; }
.gb__fill { position: absolute; left: 0; top: 0; height: 100%; width: 0%; border-radius: $r-pill; background: $subject-lilac; will-change: width; }
.gb__burst {
  position: absolute; top: 50%; left: 0%;
  width: 16px; height: 16px; border-radius: 50%;
  background: $subject-lilac; opacity: 0;
  transform: translate(-50%, -50%) scale(0);
  will-change: opacity, transform;
}

.gb__hit {
  margin-top: $sp-4; width: 100%; border: none; border-radius: $r-control;
  background: $subject-blue; color: $subject-cream;
  font-weight: 700; font-size: 13px; line-height: 1;
  padding: $sp-3 0; cursor: pointer; touch-action: none;
}
.gb__hit:active { box-shadow: $shadow-press; }

@media (max-width: 340px) {
  .gb { max-width: 220px; padding: $sp-4; }
  .gb__track { height: 15px; }
  .gb__value { font-size: 13px; }
}

@media (prefers-reduced-motion: reduce) {
  .gb__burst { display: none; }
}

html, body {
  margin: 0;
  overflow: hidden;
}

.stage {
  box-sizing: border-box;
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #ffd23f;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.gb {
  width: 100%;
  max-width: 260px;
  background: #fff7e6;
  border-radius: 16px;
  padding: 20px;
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
  box-sizing: border-box;
}

.gb__head {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  margin-bottom: 12px;
}

.gb__label {
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.04em;
  color: rgba(23, 20, 26, 0.72);
  text-transform: uppercase;
}

.gb__value {
  font-size: 15px;
  font-weight: 700;
  color: #17141a;
}

.gb__track {
  position: relative;
  height: 18px;
  border-radius: 999px;
  background: rgba(23, 20, 26, 0.1);
  overflow: visible;
}

.gb__fill {
  position: absolute;
  left: 0;
  top: 0;
  height: 100%;
  width: 0%;
  border-radius: 999px;
  background: #b9a0ff;
  will-change: width;
}

.gb__burst {
  position: absolute;
  top: 50%;
  left: 0%;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: #b9a0ff;
  opacity: 0;
  transform: translate(-50%, -50%) scale(0);
  will-change: opacity, transform;
}

.gb__hit {
  margin-top: 16px;
  width: 100%;
  border: none;
  border-radius: 12px;
  background: #2f6df6;
  color: #fff7e6;
  font-weight: 700;
  font-size: 13px;
  line-height: 1;
  padding: 12px 0;
  cursor: pointer;
  touch-action: none;
}

.gb__hit:active {
  box-shadow: 0 6px 12px rgba(23, 20, 26, 0.32);
}

@media (max-width: 340px) {
  .gb {
    max-width: 220px;
    padding: 16px;
  }
  .gb__track {
    height: 15px;
  }
  .gb__value {
    font-size: 13px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .gb__burst {
    display: none;
  }
}

(function () {
  var CHARGE_MAX = 100;
  var CHARGE_RATE = 0.062; // 계산 겹 상수: ms 당 Charge
  var HOLD_DUR = 1550; // ms, 자동 루프가 누르고 있는 시간
  var RELEASE_DUR = 700; // ms, 방출 스프링 지속
  var RELEASE_FREQ = 2 * Math.PI * 2.1 / RELEASE_DUR; // 계산 겹: 스프링 각속도
  var RELEASE_ZETA = 3.6; // 계산 겹: 스프링 감쇠 상수
  var PAUSE = 700;
  var reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;

  var gb = document.getElementById('gb');
  var track = document.getElementById('gbTrack');
  var fill = document.getElementById('gbFill');
  var burst = document.getElementById('gbBurst');
  var valueEl = document.getElementById('gbValue');
  var chargeBtn = document.getElementById('gbCharge');

  var isDemo = true;
  var value = 0;
  var holding = false;
  var holdStart = 0;
  var releaseStart = -9999;
  var releaseFromPct = 0;
  var cycleStart = 0;
  var demoPhase = 'charging'; // charging → released → pause

  function burstAt(t) {
    // 계산 겹: 방출 스프링 — 감쇠 코사인 진동으로 목표를 넘어섰다 되돌아오는 위치를 계산
    if (t < 0 || t > RELEASE_DUR) return { scale: 0, alpha: 0 };
    var x = t / RELEASE_DUR;
    var amp = Math.exp(-RELEASE_ZETA * x);
    var pos = 1 - amp * Math.cos(RELEASE_FREQ * t);
    return { scale: 1 + pos * 1.1, alpha: Math.max(0, amp * 1.15) };
  }

  function render(ts) {
    fill.style.width = value.toFixed(2) + '%';
    valueEl.textContent = Math.round(value) + '%';
    track.setAttribute('aria-valuenow', String(Math.round(value)));
    var b = burstAt(ts - releaseStart);
    burst.style.left = releaseFromPct.toFixed(2) + '%';
    burst.style.opacity = b.alpha < 0.02 ? '0' : b.alpha.toFixed(3);
    burst.style.transform = 'translate(-50%, -50%) scale(' + b.scale.toFixed(3) + ')';
  }

  function startCharge(ts) {
    holding = true;
    holdStart = ts;
  }
  function releaseCharge(ts) {
    holding = false;
    releaseFromPct = value;
    releaseStart = ts;
    value = 0;
  }

  function human() {
    if (isDemo) { gb.classList.remove('is-demo'); isDemo = false; }
  }

  chargeBtn.addEventListener('pointerdown', function (ev) {
    human();
    startCharge(performance.now());
  });
  chargeBtn.addEventListener('pointerup', function () { if (holding) releaseCharge(performance.now()); });
  chargeBtn.addEventListener('pointerleave', function () { if (holding) releaseCharge(performance.now()); });
  chargeBtn.addEventListener('pointercancel', function () { if (holding) releaseCharge(performance.now()); });
  chargeBtn.addEventListener('keydown', function (ev) {
    if (ev.key !== 'Enter' && ev.key !== ' ') return;
    ev.preventDefault();
    if (!holding) { human(); startCharge(performance.now()); }
  });
  chargeBtn.addEventListener('keyup', function (ev) {
    if (ev.key !== 'Enter' && ev.key !== ' ') return;
    if (holding) releaseCharge(performance.now());
  });

  function loop(ts) {
    if (!cycleStart) cycleStart = ts;

    if (isDemo) {
      var elapsed = ts - cycleStart;
      if (demoPhase === 'charging' && elapsed >= HOLD_DUR) {
        releaseFromPct = value;
        releaseStart = ts;
        value = 0;
        demoPhase = 'released';
      } else if (demoPhase === 'released' && ts - releaseStart >= RELEASE_DUR + PAUSE) {
        cycleStart = ts;
        demoPhase = 'charging';
        value = 0;
      } else if (demoPhase === 'charging') {
        value = Math.min(CHARGE_MAX, elapsed * CHARGE_RATE);
      }
    } else if (holding) {
      value = Math.min(CHARGE_MAX, (ts - holdStart) * CHARGE_RATE);
    }

    render(ts);
    requestAnimationFrame(loop);
  }

  if (!reduce) {
    requestAnimationFrame(loop);
  } else {
    render(0);
  }
})();

import { useEffect, useRef, useState } from 'react';
import styles from './GaugeBarChargeHoldRelease.module.scss';

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

const CHARGE_MAX = 100;
const CHARGE_RATE = 0.062; // 계산 겹 상수: ms 당 충전량
const HOLD_DUR = 1550; // ms, 자동 루프가 누르고 있는 시간
const RELEASE_DUR = 700; // ms, 방출 스프링 지속
const RELEASE_FREQ = (2 * Math.PI * 2.1) / RELEASE_DUR; // 계산 겹: 스프링 각속도
const RELEASE_ZETA = 3.6; // 계산 겹: 스프링 감쇠 상수
const PAUSE = 700;

function burstAt(t: number) {
  // 계산 겹: 방출 스프링 — 감쇠 코사인 진동으로 목표를 넘어섰다 되돌아오는 위치를 계산
  if (t < 0 || t > RELEASE_DUR) return { scale: 0, alpha: 0 };
  const x = t / RELEASE_DUR;
  const amp = Math.exp(-RELEASE_ZETA * x);
  const pos = 1 - amp * Math.cos(RELEASE_FREQ * t);
  return { scale: 1 + pos * 1.1, alpha: Math.max(0, amp * 1.15) };
}

export default function GaugeBarChargeHoldRelease() {
  const fillRef = useRef(null) as unknown as Box<HTMLDivElement>;
  const burstRef = useRef(null) as unknown as Box<HTMLDivElement>;
  const trackRef = useRef(null) as unknown as Box<HTMLDivElement>;
  const isDemoRef = useRef(true) as unknown as Box<boolean>;
  const [isDemo, setIsDemo] = useState(true);
  const [value, setValue] = useState(0);

  const valueRef = useRef(0) as unknown as Box<number>;
  const holdingRef = useRef(false) as unknown as Box<boolean>;
  const holdStartRef = useRef(0) as unknown as Box<number>;
  const releaseStartRef = useRef(-9999) as unknown as Box<number>;
  const releaseFromPctRef = useRef(0) as unknown as Box<number>;

  function human() {
    isDemoRef.current = false;
    setIsDemo(false);
  }

  function render(ts: number) {
    const fill = fillRef.current;
    const burst = burstRef.current;
    const track = trackRef.current;
    if (fill) fill.style.width = valueRef.current.toFixed(2) + '%';
    if (track) track.setAttribute('aria-valuenow', String(Math.round(valueRef.current)));
    setValue(Math.round(valueRef.current));
    const b = burstAt(ts - releaseStartRef.current);
    if (burst) {
      burst.style.left = releaseFromPctRef.current.toFixed(2) + '%';
      burst.style.opacity = b.alpha < 0.02 ? '0' : b.alpha.toFixed(3);
      burst.style.transform = 'translate(-50%, -50%) scale(' + b.scale.toFixed(3) + ')';
    }
  }

  function startCharge(ts: number) {
    holdingRef.current = true;
    holdStartRef.current = ts;
  }
  function releaseCharge(ts: number) {
    holdingRef.current = false;
    releaseFromPctRef.current = valueRef.current;
    releaseStartRef.current = ts;
    valueRef.current = 0;
  }

  useEffect(() => {
    const reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
    let cycleStart = 0;
    let demoPhase: 'charging' | 'released' = 'charging';
    let rafId = 0;

    function loop(ts: number) {
      if (!cycleStart) cycleStart = ts;

      if (isDemoRef.current) {
        const elapsed = ts - cycleStart;
        if (demoPhase === 'charging' && elapsed >= HOLD_DUR) {
          releaseFromPctRef.current = valueRef.current;
          releaseStartRef.current = ts;
          valueRef.current = 0;
          demoPhase = 'released';
        } else if (demoPhase === 'released' && ts - releaseStartRef.current >= RELEASE_DUR + PAUSE) {
          cycleStart = ts;
          demoPhase = 'charging';
          valueRef.current = 0;
        } else if (demoPhase === 'charging') {
          valueRef.current = Math.min(CHARGE_MAX, elapsed * CHARGE_RATE);
        }
      } else if (holdingRef.current) {
        valueRef.current = Math.min(CHARGE_MAX, (ts - holdStartRef.current) * CHARGE_RATE);
      }

      render(ts);
      rafId = requestAnimationFrame(loop);
    }

    if (!reduce) {
      rafId = requestAnimationFrame(loop);
    } else {
      render(0);
    }
    return () => cancelAnimationFrame(rafId);
  }, []);

  function onPointerDown() {
    human();
    startCharge(performance.now());
  }
  function onPointerUp() {
    if (holdingRef.current) releaseCharge(performance.now());
  }
  function onKeyDown(e: { key: string; preventDefault: () => void }) {
    if (e.key !== 'Enter' && e.key !== ' ') return;
    e.preventDefault();
    if (!holdingRef.current) { human(); startCharge(performance.now()); }
  }
  function onKeyUp(e: { key: string }) {
    if (e.key !== 'Enter' && e.key !== ' ') return;
    if (holdingRef.current) releaseCharge(performance.now());
  }

  return (
    <div className={`${styles.gb} ${isDemo ? styles.isDemo : ''}`}>
      <div className={styles.gbHead}>
        <span className={styles.gbLabel}>강공격</span>
        <span className={styles.gbValue}>{value}%</span>
      </div>
      <div
        className={styles.gbTrack}
        role="progressbar"
        aria-label="충전량"
        aria-valuemin={0}
        aria-valuemax={100}
        aria-valuenow={value}
        ref={trackRef}
      >
        <div className={styles.gbFill} ref={fillRef} />
        <div className={styles.gbBurst} ref={burstRef} />
      </div>
      <button
        type="button"
        className={styles.gbHit}
        onPointerDown={onPointerDown}
        onPointerUp={onPointerUp}
        onPointerLeave={onPointerUp}
        onPointerCancel={onPointerUp}
        onKeyDown={onKeyDown}
        onKeyUp={onKeyUp}
      >
        누르고 있기
      </button>
    </div>
  );
}