25 Text scramble

<!doctype html>
<html lang="ja">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>25 テキストスクランブル — Text scramble / decode effect</title>
<style>
/* dv-motion-base:start */
:root {
  --ground: #FFFFFF;
  --surface: #F3F5F8;
  --ink: #14181F;
  --muted: #5A6472;
  --accent: #1F5FA8;
  --rule: #D8DDE4;
  --accent-soft: color-mix(in srgb, var(--accent) 12%, var(--ground));
  --accent-mid: color-mix(in srgb, var(--accent) 45%, var(--ground));
  --shade: color-mix(in srgb, var(--ink) 14%, transparent);

  --font: "Zen Kaku Gothic New", "Hiragino Sans", "Noto Sans JP", "Yu Gothic", system-ui, sans-serif;
  --mono: ui-monospace, "SF Mono", Menlo, Consolas, monospace;

  --t-label: 13px;
  --t-body: 16px;
  --t-lead: 20px;
  --t-h2: 32px;
  --t-h1: clamp(40px, 7vw, 72px);

  --s1: 4px;
  --s2: 8px;
  --s3: 16px;
  --s4: 24px;
  --s5: 40px;
  --s6: 64px;
  --s7: 104px;

  --radius: 12px;
  --ease: cubic-bezier(.2, .7, .2, 1);
  --dur: .7s;
  --measure: 1080px;
}
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--ground);
  color: var(--ink);
  font-family: var(--font);
  font-size: var(--t-body);
  line-height: 1.7;
  font-feature-settings: "palt";
  overflow-x: hidden;
}
h1, h2, h3, p, ul, ol, figure { margin: 0; padding: 0; }
ul, ol { list-style: none; }
.dv-wrap { width: min(100% - 2 * var(--s4), var(--measure)); margin-inline: auto; }
.dv-label {
  min-height: 72vh;
  display: grid;
  align-content: center;
  gap: var(--s3);
  padding-block: var(--s6);
  border-bottom: 1px solid var(--rule);
}
.dv-num { font-family: var(--mono); font-size: var(--t-lead); font-weight: 700; color: var(--accent); letter-spacing: .04em; }
.dv-name { font-size: var(--t-h1); font-weight: 700; line-height: 1.15; letter-spacing: .01em; }
.dv-ai { font-family: var(--mono); font-size: var(--t-lead); color: var(--muted); }
.dv-desc { font-size: var(--t-lead); color: var(--ink); }
.dv-hint { font-size: var(--t-label); color: var(--muted); letter-spacing: .12em; margin-top: var(--s4); }
.dv-stage { padding-block: var(--s7); }
.dv-h2 { font-size: var(--t-h2); font-weight: 700; line-height: 1.3; }
.dv-lead { font-size: var(--t-lead); color: var(--muted); }
.dv-eyebrow { font-family: var(--mono); font-size: var(--t-label); color: var(--accent); letter-spacing: .12em; text-transform: uppercase; }
.dv-card { background: var(--surface); border: 1px solid var(--rule); border-radius: var(--radius); padding: var(--s4); }
.dv-ph {
  border-radius: var(--radius);
  background: linear-gradient(135deg, var(--accent-soft), var(--accent-mid) 60%, var(--accent));
  aspect-ratio: 16 / 9;
}
.dv-ph--alt { background: linear-gradient(200deg, var(--surface), var(--accent-soft) 55%, var(--accent-mid)); }
.dv-ph--ink { background: linear-gradient(160deg, var(--ink), color-mix(in srgb, var(--ink) 55%, var(--accent))); }
.dv-end {
  min-height: 60vh;
  display: grid;
  place-items: center;
  border-top: 1px solid var(--rule);
  color: var(--muted);
  font-family: var(--mono);
  font-size: var(--t-label);
  letter-spacing: .12em;
}
/* dv-motion-base:end */

/* ---- この演出だけの CSS。色は var(--…) か color-mix() のみ ---- */
.beat { min-height: 46vh; display: grid; align-content: center; gap: var(--s3); }
.sc { overflow-wrap: anywhere; }
.sc--head { font-size: var(--t-h1); font-weight: 700; line-height: 1.25; }
.sc--body { font-size: var(--t-lead); line-height: 1.8; color: var(--muted); }
.sc .ch { display: inline-block; text-align: center; white-space: pre; color: var(--accent-mid); transition: color .2s var(--ease); }
.sc .ch.is-set { color: inherit; }
.meter { display: flex; align-items: center; gap: var(--s3); font-family: var(--mono); font-size: var(--t-label); color: var(--muted); letter-spacing: .08em; }
.meter-bar { flex: 0 1 240px; height: 2px; background: var(--rule); }
.meter-bar i { display: block; height: 100%; background: var(--accent); transform-origin: left center; }
.js .meter-bar i { transform: scaleX(var(--k, 0)); }
.meter-count { font-variant-numeric: tabular-nums; }

@media (prefers-reduced-motion: reduce) {
  .sc .ch { transition: none; }
  .js .meter-bar i { transform: none; }
}
</style>
</head>
<body data-motion-number="25">
<header class="dv-label">
  <div class="dv-wrap">
    <p class="dv-num">25</p>
    <h1 class="dv-name">テキストスクランブル</h1>
    <p class="dv-ai">Text scramble / decode effect</p>
    <p class="dv-desc">乱れた文字が読める文に定まる</p>
    <p class="dv-hint">SCROLL ↓</p>
  </div>
</header>

<main class="dv-stage">
  <section class="dv-wrap beat">
    <p class="dv-eyebrow">Line 1</p>
    <h2 class="sc sc--head" data-scramble>見出しが入ります</h2>
    <div class="meter" aria-hidden="true"><span class="meter-bar"><i></i></span><span class="meter-count"></span></div>
  </section>
  <section class="dv-wrap beat">
    <p class="dv-eyebrow">Line 2</p>
    <p class="sc sc--body" data-scramble>本文のダミーです。画面に入ると、乱れた記号が左から順に読める文へ定まります。</p>
    <div class="meter" aria-hidden="true"><span class="meter-bar"><i></i></span><span class="meter-count"></span></div>
  </section>
  <section class="dv-wrap beat">
    <p class="dv-eyebrow">Line 3</p>
    <h2 class="sc sc--head" data-scramble>記号から文へ、左から順に</h2>
    <div class="meter" aria-hidden="true"><span class="meter-bar"><i></i></span><span class="meter-count"></span></div>
  </section>
  <section class="dv-wrap beat">
    <p class="dv-eyebrow">Line 4</p>
    <p class="sc sc--body" data-scramble>二つ目の本文のダミーです。一度定まった文字は、そのあと動きません。</p>
    <div class="meter" aria-hidden="true"><span class="meter-bar"><i></i></span><span class="meter-count"></span></div>
  </section>
  <section class="dv-wrap beat">
    <p class="dv-eyebrow">Line 5</p>
    <h2 class="sc sc--head" data-scramble>最後の一行も同じです</h2>
    <div class="meter" aria-hidden="true"><span class="meter-bar"><i></i></span><span class="meter-count"></span></div>
  </section>
</main>

<footer class="dv-end">END — 25 テキストスクランブル</footer>

<script>
/* dv-motion-helpers:start */
const dvReduce = matchMedia('(prefers-reduced-motion: reduce)').matches;
document.documentElement.classList.add('js');

/**
 * 画面に入った要素へ .is-in を付ける。
 * data-reveal="repeat" の要素は画面を出たら外す（何度でも再生）。
 */
function dvReveal(selector = '[data-reveal]', { threshold = 0.2, rootMargin = '0px 0px -8% 0px' } = {}) {
  const els = [...document.querySelectorAll(selector)];
  if (dvReduce || !('IntersectionObserver' in window)) {
    els.forEach((el) => el.classList.add('is-in'));
    return;
  }
  const io = new IntersectionObserver((entries) => {
    for (const e of entries) {
      if (e.isIntersecting) {
        e.target.classList.add('is-in');
        if (e.target.dataset.reveal !== 'repeat') io.unobserve(e.target);
      } else if (e.target.dataset.reveal === 'repeat') {
        e.target.classList.remove('is-in');
      }
    }
  }, { threshold, rootMargin });
  els.forEach((el) => io.observe(el));
}

/**
 * スクロール量を 0〜1 にして、各 [data-progress] 要素の CSS 変数 --p に書く。
 *   data-progress="through" : 要素の上端が画面の下端に来たとき 0、下端が画面の上端を抜けたとき 1
 *   data-progress="pin"     : 要素の上端が画面の上端に来たとき 0、下端が画面の下端に来たとき 1
 *                             （中に position: sticky の箱を持つ、背の高い区画用）
 *   data-progress="page"    : ページ全体のスクロール量
 * onUpdate(el, p) を渡すと、値が変わるたびに呼ばれる。
 */
function dvProgress(onUpdate) {
  const els = [...document.querySelectorAll('[data-progress]')];
  const clamp = (n) => Math.min(1, Math.max(0, n));
  let queued = false;
  const measure = () => {
    queued = false;
    const vh = window.innerHeight;
    for (const el of els) {
      const r = el.getBoundingClientRect();
      let p;
      if (el.dataset.progress === 'pin') p = r.height > vh ? -r.top / (r.height - vh) : 0;
      else if (el.dataset.progress === 'page') {
        const max = document.documentElement.scrollHeight - vh;
        p = max > 0 ? window.scrollY / max : 0;
      } else p = (vh - r.top) / (vh + r.height);
      p = clamp(p);
      el.style.setProperty('--p', p.toFixed(4));
      if (onUpdate) onUpdate(el, p);
    }
  };
  const request = () => {
    if (!queued) { queued = true; requestAnimationFrame(measure); }
  };
  addEventListener('scroll', request, { passive: true });
  addEventListener('resize', request);
  measure();
}
/* dv-motion-helpers:end */

/* ---- この演出だけの JS ---- */
const GLYPHS = ['#', '%', '&', '*', '+', '=', '?', '/', '<', '>', '!', '$', '@', '~', '^', '◆', '■', '▲', '●', '×'];
const DURATION = 1200; // 1 行が定まりきるまで
const SWAP = 50;       // 記号を切り替える間隔
const HOLD = 0.2;      // 最初の 1 字が定まるまで、全体が乱れたままの割合
const SLIM = 15;       // 先頭の 15 個は幅の狭い記号。句読点のような狭い字にはこちらだけを使う
const glyph = (slim) => GLYPHS[Math.floor(Math.random() * (slim ? SLIM : GLYPHS.length))];

const lines = [...document.querySelectorAll('[data-scramble]')].map((el) => {
  const meter = el.parentElement.querySelector('.meter');
  const text = el.textContent.trim();
  const total = Array.from(text).filter((ch) => !/\s/.test(ch)).length;
  return { el, text, total, bar: meter.querySelector('i'), count: meter.querySelector('.meter-count'), chars: [] };
});
const report = (line, set) => {
  line.bar.style.setProperty('--k', (set / line.total).toFixed(3));
  line.count.textContent = `${set} / ${line.total}`;
};
lines.forEach((line) => line.el.setAttribute('aria-label', line.text));

if (dvReduce || !('IntersectionObserver' in window)) {
  lines.forEach((line) => report(line, line.total));
} else {
  // 1 字ずつ <span> に割る。空白は割らない。
  for (const line of lines) {
    line.el.textContent = '';
    for (const ch of Array.from(line.text)) {
      if (/\s/.test(ch)) { line.el.appendChild(document.createTextNode(ch)); continue; }
      const span = document.createElement('span');
      span.className = 'ch';
      span.setAttribute('aria-hidden', 'true');
      span.textContent = ch;
      line.el.appendChild(span);
      line.chars.push({ span, ch });
    }
  }
  // 記号は元の字と幅が違う。元の字の幅を em で固定して、切り替えのたびに行が揺れないようにする。
  for (const line of lines) {
    const size = parseFloat(getComputedStyle(line.el).fontSize);
    line.widths = line.chars.map(({ span }) => span.getBoundingClientRect().width / size);
  }
  for (const line of lines) {
    line.chars.forEach(({ span }, i) => {
      span.style.width = `${line.widths[i].toFixed(3)}em`;
      span.textContent = glyph(line.chars[i].slim = line.widths[i] < 0.8);
    });
    report(line, 0);
  }

  const decode = (line) => {
    const n = line.chars.length;
    const start = performance.now();
    let set = 0;
    let lastTick = -1;
    const frame = (now) => {
      const t = now - start;
      const due = t >= DURATION ? n : Math.max(0, Math.floor(((t / DURATION - HOLD) / (1 - HOLD)) * n));
      for (; set < due; set++) {
        line.chars[set].span.textContent = line.chars[set].ch;
        line.chars[set].span.classList.add('is-set');
      }
      const tick = Math.floor(t / SWAP);
      if (tick !== lastTick) {
        lastTick = tick;
        for (let i = set; i < n; i++) line.chars[i].span.textContent = glyph(line.chars[i].slim);
      }
      report(line, set);
      if (set < n) requestAnimationFrame(frame);
    };
    requestAnimationFrame(frame);
  };

  // 画面の下から 30% の線を越えた行から定める。上側は広く取り、飛び越した行も拾う。
  const byEl = new Map(lines.map((line) => [line.el, line]));
  const io = new IntersectionObserver((entries) => {
    for (const e of entries) {
      if (!e.isIntersecting) continue;
      io.unobserve(e.target);
      decode(byEl.get(e.target));
    }
  }, { threshold: 0.9, rootMargin: '100000px 0px -30% 0px' });
  lines.forEach((line) => io.observe(line.el));
}
</script>
</body>
</html>