磁吸按钮

按钮的视觉层随指针微移,指针离开后回到原位。

13 / 22Magnetic button打开示例

虚线标记按钮原位

移动鼠标观察按钮偏移。点按按钮,或用键盘确认。

等待确认

  1. 使用场景

    主操作按钮。例如作品集的「查看作品」在指针靠近时给出轻微的方向反馈。

  2. 行为定义

    鼠标在固定热区内移动时,按钮视觉层持续跟随坐标,每轴最多偏移 12 px。移出、取消或失焦后回中,触屏点按和键盘操作都能激活按钮。

  3. 实现要点

    以固定热区的中心计算偏移,只对内部视觉层应用 transform。用原位轮廓标出位移基准。

原生 HTML / CSS / JS

完整示例,可另存为 HTML 直接打开。

打开示例

查看源码
<!doctype html>
<html lang="zh-CN">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>磁吸按钮 · 原生示例</title>
  <script>
    const theme = new URLSearchParams(location.search).get('theme');
    if (theme === 'dark' || (!theme && matchMedia('(prefers-color-scheme: dark)').matches)) {
      document.documentElement.dataset.theme = 'dark';
    }
  </script>
  <style>
    :root {
      color-scheme: light;
      --bg: #fbfaf7; --surface: #fff; --surface-2: #edf3f6;
      --text: #222c36; --text-2: #434f5d; --line-strong: #82939f;
      --family-pointer: #275d7f; --accent: #b8412c;
      --btn-bg: #b8412c; --btn-fg: #fff; --btn-hover: #963324;
    }
    :root[data-theme="dark"] {
      color-scheme: dark;
      --bg: #19222d; --surface: #222e3c; --surface-2: #2b3c4d;
      --text: #f6f5f1; --text-2: #d8dce1; --line-strong: #8396a8;
      --family-pointer: #9dc5e4; --accent: #ff9d7c;
      --btn-bg: #ff9d7c; --btn-fg: #281912; --btn-hover: #ffb399;
    }
    html { background: var(--bg); }
    body { max-width: 54rem; margin: 2rem auto; padding-inline: 1rem; color: var(--text); font: 1rem/1.55 system-ui, sans-serif; }
    *, *::before, *::after { box-sizing: border-box; }
    .pointer-comparison {
  --pointer-accent: var(--family-pointer);
  --pointer-rest: color-mix(in srgb, var(--surface-2) 88%, var(--pointer-accent));
  max-inline-size: 54rem;
  margin-inline: auto;
  color: var(--text);
}

.pc-frame {
  position: relative;
  padding: clamp(.95rem, 2.5vw, 1.6rem);
  border-radius: 14px;
  background: var(--surface-2);
}

.pc-magnetic-frame {
  display: grid;
  place-items: center;
  min-block-size: clamp(10rem, 27vw, 15rem);
  background: var(--pointer-rest);
}

.pc-axis {
  position: absolute;
  inset: 1rem;
  pointer-events: none;
}

.pc-axis::before, .pc-axis::after {
  position: absolute;
  background: var(--line-strong);
  opacity: .45;
  content: '';
}

.pc-axis::before { inset: 50% 0 auto; block-size: 1px; }
.pc-axis::after { inset: 0 auto 0 50%; inline-size: 1px; }

.pc-magnetic-hit {
  position: relative;
  display: grid;
  place-items: center;
  padding: 16px;
  border: 0;
  border-radius: 14px;
  background: transparent;
  font: inherit;
  cursor: pointer;
}

.pc-magnetic-origin {
  position: absolute;
  inset: 16px;
  border: 1px dashed var(--pointer-accent);
  border-radius: 10px;
  pointer-events: none;
}

.pc-magnetic-visual {
  display: grid;
  place-items: center;
  min-inline-size: 7.5rem;
  min-block-size: 2.75rem;
  padding-inline: .9rem;
  border-radius: 10px;
  background: var(--btn-bg);
  color: var(--btn-fg);
  font-size: .875rem;
  font-weight: 600;
  pointer-events: none;
  transition-property: transform;
  transition-timing-function: cubic-bezier(.22, 1, .36, 1);
}

.pc-magnetic-hit:hover .pc-magnetic-visual,
.pc-magnetic-hit:active .pc-magnetic-visual { background: var(--btn-hover); }

.pc-legend {
  position: absolute;
  inset: auto .9rem .55rem auto;
  margin: 0;
  color: var(--text-2);
  font-size: .75rem;
}

.pc-pulse-stage { position: relative; }

.pc-orbit {
  position: relative;
  display: flex;
  justify-content: space-between;
  align-items: end;
  overflow: hidden;
  box-sizing: border-box;
  aspect-ratio: 2 / 1;
  padding: clamp(.9rem, 3.2vw, 2rem);
  border-radius: 12px;
  background: var(--pointer-rest);
  pointer-events: none;
}

.pc-orbit svg { position: absolute; inset: 0; inline-size: 100%; block-size: 100%; }
.pc-orbit-label, .pc-orbit-index { position: relative; }
.pc-orbit-label { display: grid; gap: .25rem; }
.pc-orbit-label strong { font-size: clamp(1rem, 3vw, 1.65rem); letter-spacing: -.025em; }
.pc-orbit-label small, .pc-orbit-index { font-size: clamp(.6rem, 1.35vw, .8rem); letter-spacing: .05em; }

.pc-pulse-outline {
  position: absolute;
  inset: 0;
  border: 2px solid var(--accent);
  border-radius: 12px;
  opacity: 0;
  pointer-events: none;
}

.pointer-comparison[data-pulse-state="static"] .pc-pulse-outline { opacity: 1; }

.pc-instructions {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: .25rem 1rem;
  margin-block: .65rem .95rem;
  color: var(--text-2);
  font-size: .875rem;
}

.pc-instructions p { margin: 0; }
.pc-status { color: var(--pointer-accent); }

.pc-play {
  min-block-size: 2.75rem;
  padding: .35rem .75rem;
  border: 1px solid var(--line-strong);
  border-radius: 10px;
  background: var(--surface);
  color: var(--text);
  font: inherit;
  font-size: .875rem;
  cursor: pointer;
}

.pc-play:hover { border-color: var(--pointer-accent); background: var(--pointer-rest); }
.pc-play:focus-visible, .pc-magnetic-hit:focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; }
.pc-play[hidden], .pc-magnetic-hit[hidden] { display: none; }

@media (max-width: 42rem) {
  .pc-orbit { aspect-ratio: 1.6 / 1; }
}

@media (prefers-reduced-motion: reduce) {
  .pc-magnetic-visual { transform: none !important; transition: none; }
}

  </style>
  
<style>.demo-guide {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: .5rem .9rem;
  min-inline-size: 0;
  margin-block: 0 .75rem;
  padding-block-end: .5rem;
  border-block-end: 1px solid var(--line-hi, #b8c4cd);
  color: var(--text-2, #434f5d);
  font-size: .8125rem;
  line-height: 1.5;
}

.trigger-stage > .demo-guide {
  margin: .35rem clamp(.85rem, 2.2vw, 1.4rem) 0;
}

.demo-guide [data-guide-caption] { margin: 0; }

.demo-guide > button[data-guide-replay] {
  flex: none;
  min-block-size: 44px;
  margin: 0;
  padding: .35rem .65rem;
  border: 1px solid var(--line-strong, #82939f);
  border-radius: 7px;
  background: var(--surface, #fff);
  color: var(--text, #222c36);
  font: inherit;
  font-weight: 550;
  cursor: pointer;
}

.demo-guide > button[data-guide-replay]:hover { border-color: var(--accent-text, #963324); }
.demo-guide > button[data-guide-replay]:focus-visible { outline: 2px solid var(--accent-text, #963324); outline-offset: 2px; }

.demo-guide-cursor {
  position: fixed;
  z-index: 20;
  inset: 0 auto auto 0;
  inline-size: 20px;
  block-size: 24px;
  pointer-events: none;
}

.demo-guide-cursor svg { display: block; inline-size: 100%; block-size: 100%; }
.demo-guide-cursor::before {
  position: absolute;
  inset: -7px auto auto -7px;
  inline-size: 18px;
  block-size: 18px;
  border: 2px solid var(--accent-text, #963324);
  border-radius: 50%;
  content: '';
  opacity: 0;
}
.demo-guide-cursor[data-press]::before { opacity: 1; }
@media (prefers-reduced-motion: reduce) { .demo-guide-cursor { display: none; } }
</style>
</head>
<body>
  <main>
    <h1>磁吸按钮</h1>
    <section class="pointer-comparison" data-pointer-comparison="magnetic-button" aria-label="磁吸按钮试玩">
  
  <div class="pc-frame pc-magnetic-frame">
    <div class="pc-axis" aria-hidden="true"></div>
    <button class="pc-magnetic-hit" type="button" data-magnetic-hit hidden>
      <span class="pc-magnetic-origin" aria-hidden="true"></span>
      <span class="pc-magnetic-visual" data-magnetic-visual>点按确认</span>
    </button>
    <noscript><span class="pc-magnetic-visual">按钮原位</span></noscript>
    <p class="pc-legend">虚线标记按钮原位</p>
  </div>
  <div class="pc-instructions">
    <p>移动鼠标观察按钮偏移。点按按钮,或用键盘确认。</p>
    <p class="pc-status" data-pc-status role="status">等待确认</p>
  </div>
</section>
  </main>
  <script>
const maximumOffset = 12;
const returnDuration = 240;

/** @param {HTMLElement} visual @param {number} x @param {number} y @param {boolean} returning */
function positionNative(visual, x, y, returning) {
  visual.style.transitionDuration = returning ? `${returnDuration}ms` : '0ms';
  visual.style.transform = `translate(${x}px, ${y}px)`;
}

/** @param {HTMLElement} root @param {typeof positionNative} [position] */
function bindMagneticButton(root, position = positionNative) {
  const button = root.querySelector('[data-magnetic-hit]');
  const visual = root.querySelector('[data-magnetic-visual]');
  const status = root.querySelector('[data-pc-status]');
  if (!(button instanceof HTMLButtonElement) || !(visual instanceof HTMLElement) || !status) return;

  const reduced = matchMedia('(prefers-reduced-motion: reduce)');
  let confirmations = 0;
  let frame = 0;
  let clientX = 0;
  let clientY = 0;

  /** @param {number} fraction */
  const offset = (fraction) => maximumOffset * Math.max(-1, Math.min(1, fraction));

  /** @param {PointerEvent} event */
  const follow = (event) => {
    if (event.pointerType !== 'mouse' || reduced.matches) return;
    clientX = event.clientX;
    clientY = event.clientY;
    if (frame) return;
    frame = requestAnimationFrame(() => {
      frame = 0;
      const { left, top, width, height } = button.getBoundingClientRect();
      const x = offset((2 * (clientX - left)) / width - 1);
      const y = offset((2 * (clientY - top)) / height - 1);
      position(visual, x, y, false);
    });
  };
  const returnHome = () => {
    cancelAnimationFrame(frame);
    frame = 0;
    position(visual, 0, 0, !reduced.matches);
  };

  button.addEventListener('pointerenter', follow);
  button.addEventListener('pointermove', follow);
  button.addEventListener('pointerleave', returnHome);
  button.addEventListener('pointercancel', returnHome);
  button.addEventListener('blur', returnHome);
  window.addEventListener('blur', returnHome);
  reduced.addEventListener('change', returnHome);
  button.addEventListener('click', () => {
    confirmations += 1;
    status.textContent = `已确认 · 第 ${confirmations} 次`;
  });
  button.hidden = false;
}


const demo = document.querySelector('[data-pointer-comparison]');
bindMagneticButton(demo);
  </script>
<script>
(() => {
/** @param {number} duration @param {AbortSignal} signal @param {(progress: number) => void} [render] */
function guideBeat(duration, signal, render) {
  if (signal.aborted) return Promise.resolve();
  if (duration === 0) {
    render?.(1);
    return Promise.resolve();
  }

  return new Promise((resolve) => {
    let timer = 0;
    let frame = 0;
    const done = () => {
      clearTimeout(timer);
      cancelAnimationFrame(frame);
      signal.removeEventListener('abort', done);
      resolve(undefined);
    };
    signal.addEventListener('abort', done, { once: true });
    if (!render) {
      timer = window.setTimeout(done, duration);
      return;
    }

    const start = performance.now();
    const tick = (now) => {
      const progress = Math.min(1, (now - start) / duration);
      render(progress);
      if (progress === 1) done();
      else if (!signal.aborted) frame = requestAnimationFrame(tick);
    };
    frame = requestAnimationFrame(tick);
  });
}

/** @param {HTMLElement} root @param {import('./demo-guide-cases').DemoGuide} guide */
function bindDemoGuide(root, guide) {
  const view = root.querySelector(guide.view);
  if (!view || root.dataset.guideState || guide.steps.some(({ target }) => !root.querySelector(target))) return;

  const dock = guide.dock ? root.querySelector(guide.dock) : null;
  const bar = document.createElement('div');
  bar.className = 'demo-guide';
  bar.innerHTML = '<p data-guide-caption></p><button type="button" data-guide-replay>重播导览</button>';
  const caption = bar.querySelector('[data-guide-caption]');
  const replay = bar.querySelector('button');
  const heading = root === document.body ? root.querySelector('h1') : null;
  if (dock) dock.prepend(bar);
  else if (heading) heading.after(bar);
  else root.prepend(bar);

  const cursor = document.createElement('div');
  cursor.className = 'demo-guide-cursor';
  cursor.setAttribute('aria-hidden', 'true');
  cursor.hidden = true;
  cursor.innerHTML = '<svg viewBox="0 0 20 24" focusable="false"><path d="M2 2v17l4.8-4.5L10 21l3.2-1.6-3.2-6.2 6.6-.7L2 2Z" fill="#222c36" stroke="#fff" stroke-width="1.5" stroke-linejoin="round"/></svg>';
  document.body.append(cursor);

  const reduced = matchMedia('(prefers-reduced-motion: reduce)');
  const threshold = .5;
  const idleCaption = '导览在画面进入视口后播放一次。';
  const reducedCaption = '可重播关键状态,或直接操作。';
  const reset = guide.reset ? (root.matches(guide.reset) ? root : root.querySelector(guide.reset)) : null;
  const releaseTarget = guide.release ? root.querySelector(guide.release) : null;
  let autoPending = !reduced.matches;
  let inView = false;
  let playbackScroll = window.scrollY;
  /** @type {AbortController | undefined} */
  let run;
  /** @type {[number, number] | undefined} */
  let cursorPosition;

  root.dataset.guideState = 'idle';
  caption.textContent = reduced.matches ? reducedCaption : idleCaption;

  function hideCursor() {
    cursor.hidden = true;
    delete cursor.dataset.press;
    cursorPosition = undefined;
  }

  /** @param {PointerEvent} [pointer] */
  function stop(pointer) {
    autoPending = false;
    if (!run) return;
    run.abort();
    run = undefined;
    hideCursor();
    if (releaseTarget) {
      // A real pointer inside the target keeps its hover when the guide yields.
      if (pointer) sendPointer(releaseTarget, 'pointerenter', [pointer.clientX, pointer.clientY]);
      else sendPointer(releaseTarget, 'pointerleave', [0, 0]);
    }
    reset?.dispatchEvent(new Event('formtempo:guide-cancel'));
    root.dataset.guideState = 'interrupted';
    caption.textContent = '导览已停止,可以继续手动操作。';
  }

  /** @param {[number, number]} position */
  function moveCursor(position) {
    cursor.hidden = false;
    cursor.style.transform = `translate3d(${position[0]}px, ${position[1]}px, 0)`;
    cursorPosition = position;
  }

  /** @param {Element} target @param {readonly [number, number]} point */
  function location(target, [x, y]) {
    const rect = target.getBoundingClientRect();
    return /** @type {[number, number]} */ ([rect.left + rect.width * x, rect.top + rect.height * y]);
  }

  /** @param {Element} target @param {string} type @param {readonly [number, number]} position */
  function sendPointer(target, type, [clientX, clientY]) {
    target.dispatchEvent(new PointerEvent(type, { pointerType: 'mouse', clientX, clientY }));
  }

  /** @param {HTMLInputElement} slider @param {number} value */
  function setProgress(slider, value) {
    const next = Math.round(value);
    if (slider.valueAsNumber === next) return;
    slider.value = String(next);
    slider.dispatchEvent(new Event('input', { bubbles: true }));
  }

  /** @param {number} value */
  function showReducedProgress(value) {
    const options = Array.from(root.querySelectorAll('button[data-driven-step], button[data-scale-step], button[data-progress-step], button[data-progress]'));
    const percent = (button) => button.hasAttribute('data-progress')
      ? Number(button.getAttribute('data-progress')) * 100
      : Number(button.getAttribute('data-driven-step') ?? button.getAttribute('data-scale-step') ?? button.getAttribute('data-progress-step'));
    options.sort((a, b) => Math.abs(percent(a) - value) - Math.abs(percent(b) - value));
    if (options[0] instanceof HTMLButtonElement) options[0].click();
  }

  /** @param {import('./demo-guide-cases').DemoGuide['steps'][number]} step @param {AbortSignal} signal */
  async function playStep(step, signal) {
    const target = root.querySelector(step.target);
    if (!target) return;
    caption.textContent = step.text;
    const { action, value = 0, point = [.5, .5] } = step;

    if (action === 'progress' && target instanceof HTMLInputElement) {
      if (reduced.matches) {
        showReducedProgress(value);
      } else {
        const from = target.valueAsNumber;
        await guideBeat(step.duration ?? 0, signal, (progress) => {
          const current = from + (value - from) * progress;
          setProgress(target, current);
          moveCursor(location(target, [.04 + .92 * current / 100, .65]));
        });
      }
    } else {
      if (!reduced.matches) {
        const to = location(target, point);
        const [x, y] = point;
        const entry = x < .25 ? [-.08, y] : x > .75 ? [1.08, y] : [x, y < .5 ? -.08 : 1.08];
        const from = action === 'enter' ? location(target, /** @type {[number, number]} */ (entry))
          : cursorPosition ?? [to[0] + 26, to[1] + 19];
        const duration = action === 'leave' ? 200 : 340;
        await guideBeat(duration, signal, (progress) => {
          const t = 1 - (1 - progress) ** 3;
          const end = location(target, point);
          const position = /** @type {[number, number]} */ ([
            from[0] + (end[0] - from[0]) * t,
            from[1] + (end[1] - from[1]) * t,
          ]);
          moveCursor(position);
          if (action === 'move') sendPointer(target, 'pointermove', position);
        });
      }
      if (signal.aborted) return;

      if (action === 'click' && target instanceof HTMLElement) {
        if (!reduced.matches) {
          cursor.dataset.press = '';
          await guideBeat(125, signal);
          if (signal.aborted) return;
        }
        target.click();
        delete cursor.dataset.press;
      } else if (action === 'enter' || action === 'leave') {
        sendPointer(target, `pointer${action}`, location(target, point));
      }
    }

    await guideBeat(reduced.matches ? 600 : step.hold ?? 500, signal);
  }

  function bringViewIntoFrame() {
    const rect = view.getBoundingClientRect();
    const visibleHeight = Math.min(rect.bottom, window.innerHeight) - Math.max(rect.top, 0);
    if (visibleHeight < rect.height * threshold) view.scrollIntoView({ block: 'center', behavior: 'instant' });
  }

  async function start(replaying = false) {
    stop();
    const controller = new AbortController();
    const { signal } = controller;
    run = controller;
    root.dataset.guideState = 'playing';

    if (guide.ready) {
      caption.textContent = '正在等待视频就绪…';
      const deadline = performance.now() + 4000;
      while (!signal.aborted && !root.querySelector(guide.ready) && performance.now() < deadline &&
        !root.querySelector('[data-video-state="error"]')) {
        await guideBeat(90, signal);
      }
      if (signal.aborted) return;
      if (!root.querySelector(guide.ready)) {
        run = undefined;
        root.dataset.guideState = 'unavailable';
        caption.textContent = '视频暂未就绪,可以查看关键帧或重播。';
        return;
      }
    }

    reset?.dispatchEvent(new Event('formtempo:guide-reset'));
    if (replaying) bringViewIntoFrame();
    playbackScroll = window.scrollY;
    const steps = (reduced.matches && guide.reducedSteps) || guide.steps;
    for (const step of steps) {
      if (signal.aborted) return;
      await playStep(step, signal);
    }
    if (signal.aborted) return;

    run = undefined;
    hideCursor();
    root.dataset.guideState = 'complete';
    caption.textContent = '导览结束,可以继续手动操作。';
  }

  function tryAutoplay() {
    if (autoPending && inView && !document.hidden) void start();
  }

  if (typeof IntersectionObserver === 'function') {
    const observer = new IntersectionObserver(([entry]) => {
      inView = entry.intersectionRatio >= threshold;
      if (!entry.isIntersecting && run) stop();
      tryAutoplay();
    }, { threshold: [0, threshold] });
    observer.observe(view);
  }

  replay.addEventListener('click', () => {
    bringViewIntoFrame();
    void start(true);
  });

  const takeOver = (event) => {
    if (!event.isTrusted || replay.contains(event.target)) return;
    if (!run) {
      if (event.type === 'wheel' || !(event.target instanceof Element)) return;
      if (!event.target.closest('button, input') && !view.contains(event.target)) return;
    }
    const pointer = event instanceof PointerEvent && event.pointerType === 'mouse' && releaseTarget?.contains(event.target)
      ? event : undefined;
    stop(pointer);
  };
  for (const event of ['pointerdown', 'keydown', 'focusin', 'input', 'click', 'wheel']) {
    root.addEventListener(event, takeOver, { capture: true, passive: true });
  }
  if (guide.steps.some(({ action }) => action === 'enter' || action === 'move')) {
    view.addEventListener('pointermove', takeOver, { capture: true, passive: true });
  }
  if (guide.pageScrollInput) {
    window.addEventListener('scroll', () => {
      if (run && window.scrollY !== playbackScroll) stop();
    }, { passive: true });
  }
  document.addEventListener('visibilitychange', () => {
    if (document.hidden && run) stop();
    else tryAutoplay();
  });
  reduced.addEventListener('change', () => {
    if (!reduced.matches) return;
    const wasIdle = root.dataset.guideState === 'idle';
    stop();
    if (wasIdle) caption.textContent = reducedCaption;
  });
}

bindDemoGuide(document.body, {"view":"[data-magnetic-hit]","release":"[data-magnetic-hit]","reducedSteps":[{"target":"[data-magnetic-hit]","action":"click","text":"减少动态效果时,按钮保持原位,仍可点按确认。"}],"steps":[{"target":"[data-magnetic-hit]","action":"move","text":"指针靠左时,按钮视觉层向左偏移。","point":[0.12,0.45],"hold":360},{"target":"[data-magnetic-hit]","action":"move","text":"移向右下角,按钮跟着偏移。","point":[0.88,0.8],"hold":360},{"target":"[data-magnetic-hit]","action":"leave","text":"离开热区,按钮回到虚线标出的原位。","point":[1.15,0.85]}]});
})();
</script>
</body>
</html>

GSAP 3.15.0

完整示例,从 CDN 加载指定版本。

打开示例

查看源码
<!doctype html>
<html lang="zh-CN">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>磁吸按钮 · GSAP示例</title>
  <script>
    const theme = new URLSearchParams(location.search).get('theme');
    if (theme === 'dark' || (!theme && matchMedia('(prefers-color-scheme: dark)').matches)) {
      document.documentElement.dataset.theme = 'dark';
    }
  </script>
  <style>
    :root {
      color-scheme: light;
      --bg: #fbfaf7; --surface: #fff; --surface-2: #edf3f6;
      --text: #222c36; --text-2: #434f5d; --line-strong: #82939f;
      --family-pointer: #275d7f; --accent: #b8412c;
      --btn-bg: #b8412c; --btn-fg: #fff; --btn-hover: #963324;
    }
    :root[data-theme="dark"] {
      color-scheme: dark;
      --bg: #19222d; --surface: #222e3c; --surface-2: #2b3c4d;
      --text: #f6f5f1; --text-2: #d8dce1; --line-strong: #8396a8;
      --family-pointer: #9dc5e4; --accent: #ff9d7c;
      --btn-bg: #ff9d7c; --btn-fg: #281912; --btn-hover: #ffb399;
    }
    html { background: var(--bg); }
    body { max-width: 54rem; margin: 2rem auto; padding-inline: 1rem; color: var(--text); font: 1rem/1.55 system-ui, sans-serif; }
    *, *::before, *::after { box-sizing: border-box; }
    .pointer-comparison {
  --pointer-accent: var(--family-pointer);
  --pointer-rest: color-mix(in srgb, var(--surface-2) 88%, var(--pointer-accent));
  max-inline-size: 54rem;
  margin-inline: auto;
  color: var(--text);
}

.pc-frame {
  position: relative;
  padding: clamp(.95rem, 2.5vw, 1.6rem);
  border-radius: 14px;
  background: var(--surface-2);
}

.pc-magnetic-frame {
  display: grid;
  place-items: center;
  min-block-size: clamp(10rem, 27vw, 15rem);
  background: var(--pointer-rest);
}

.pc-axis {
  position: absolute;
  inset: 1rem;
  pointer-events: none;
}

.pc-axis::before, .pc-axis::after {
  position: absolute;
  background: var(--line-strong);
  opacity: .45;
  content: '';
}

.pc-axis::before { inset: 50% 0 auto; block-size: 1px; }
.pc-axis::after { inset: 0 auto 0 50%; inline-size: 1px; }

.pc-magnetic-hit {
  position: relative;
  display: grid;
  place-items: center;
  padding: 16px;
  border: 0;
  border-radius: 14px;
  background: transparent;
  font: inherit;
  cursor: pointer;
}

.pc-magnetic-origin {
  position: absolute;
  inset: 16px;
  border: 1px dashed var(--pointer-accent);
  border-radius: 10px;
  pointer-events: none;
}

.pc-magnetic-visual {
  display: grid;
  place-items: center;
  min-inline-size: 7.5rem;
  min-block-size: 2.75rem;
  padding-inline: .9rem;
  border-radius: 10px;
  background: var(--btn-bg);
  color: var(--btn-fg);
  font-size: .875rem;
  font-weight: 600;
  pointer-events: none;
  transition-property: transform;
  transition-timing-function: cubic-bezier(.22, 1, .36, 1);
}

.pc-magnetic-hit:hover .pc-magnetic-visual,
.pc-magnetic-hit:active .pc-magnetic-visual { background: var(--btn-hover); }

.pc-legend {
  position: absolute;
  inset: auto .9rem .55rem auto;
  margin: 0;
  color: var(--text-2);
  font-size: .75rem;
}

.pc-pulse-stage { position: relative; }

.pc-orbit {
  position: relative;
  display: flex;
  justify-content: space-between;
  align-items: end;
  overflow: hidden;
  box-sizing: border-box;
  aspect-ratio: 2 / 1;
  padding: clamp(.9rem, 3.2vw, 2rem);
  border-radius: 12px;
  background: var(--pointer-rest);
  pointer-events: none;
}

.pc-orbit svg { position: absolute; inset: 0; inline-size: 100%; block-size: 100%; }
.pc-orbit-label, .pc-orbit-index { position: relative; }
.pc-orbit-label { display: grid; gap: .25rem; }
.pc-orbit-label strong { font-size: clamp(1rem, 3vw, 1.65rem); letter-spacing: -.025em; }
.pc-orbit-label small, .pc-orbit-index { font-size: clamp(.6rem, 1.35vw, .8rem); letter-spacing: .05em; }

.pc-pulse-outline {
  position: absolute;
  inset: 0;
  border: 2px solid var(--accent);
  border-radius: 12px;
  opacity: 0;
  pointer-events: none;
}

.pointer-comparison[data-pulse-state="static"] .pc-pulse-outline { opacity: 1; }

.pc-instructions {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: .25rem 1rem;
  margin-block: .65rem .95rem;
  color: var(--text-2);
  font-size: .875rem;
}

.pc-instructions p { margin: 0; }
.pc-status { color: var(--pointer-accent); }

.pc-play {
  min-block-size: 2.75rem;
  padding: .35rem .75rem;
  border: 1px solid var(--line-strong);
  border-radius: 10px;
  background: var(--surface);
  color: var(--text);
  font: inherit;
  font-size: .875rem;
  cursor: pointer;
}

.pc-play:hover { border-color: var(--pointer-accent); background: var(--pointer-rest); }
.pc-play:focus-visible, .pc-magnetic-hit:focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; }
.pc-play[hidden], .pc-magnetic-hit[hidden] { display: none; }

@media (max-width: 42rem) {
  .pc-orbit { aspect-ratio: 1.6 / 1; }
}

@media (prefers-reduced-motion: reduce) {
  .pc-magnetic-visual { transform: none !important; transition: none; }
}

  </style>
  <script src="https://cdn.jsdelivr.net/npm/gsap@3.15.0/dist/gsap.min.js"></script>
<style>.demo-guide {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: .5rem .9rem;
  min-inline-size: 0;
  margin-block: 0 .75rem;
  padding-block-end: .5rem;
  border-block-end: 1px solid var(--line-hi, #b8c4cd);
  color: var(--text-2, #434f5d);
  font-size: .8125rem;
  line-height: 1.5;
}

.trigger-stage > .demo-guide {
  margin: .35rem clamp(.85rem, 2.2vw, 1.4rem) 0;
}

.demo-guide [data-guide-caption] { margin: 0; }

.demo-guide > button[data-guide-replay] {
  flex: none;
  min-block-size: 44px;
  margin: 0;
  padding: .35rem .65rem;
  border: 1px solid var(--line-strong, #82939f);
  border-radius: 7px;
  background: var(--surface, #fff);
  color: var(--text, #222c36);
  font: inherit;
  font-weight: 550;
  cursor: pointer;
}

.demo-guide > button[data-guide-replay]:hover { border-color: var(--accent-text, #963324); }
.demo-guide > button[data-guide-replay]:focus-visible { outline: 2px solid var(--accent-text, #963324); outline-offset: 2px; }

.demo-guide-cursor {
  position: fixed;
  z-index: 20;
  inset: 0 auto auto 0;
  inline-size: 20px;
  block-size: 24px;
  pointer-events: none;
}

.demo-guide-cursor svg { display: block; inline-size: 100%; block-size: 100%; }
.demo-guide-cursor::before {
  position: absolute;
  inset: -7px auto auto -7px;
  inline-size: 18px;
  block-size: 18px;
  border: 2px solid var(--accent-text, #963324);
  border-radius: 50%;
  content: '';
  opacity: 0;
}
.demo-guide-cursor[data-press]::before { opacity: 1; }
@media (prefers-reduced-motion: reduce) { .demo-guide-cursor { display: none; } }
</style>
</head>
<body>
  <main>
    <h1>磁吸按钮</h1>
    <section class="pointer-comparison" data-pointer-comparison="magnetic-button" aria-label="磁吸按钮试玩">
  
  <div class="pc-frame pc-magnetic-frame">
    <div class="pc-axis" aria-hidden="true"></div>
    <button class="pc-magnetic-hit" type="button" data-magnetic-hit hidden>
      <span class="pc-magnetic-origin" aria-hidden="true"></span>
      <span class="pc-magnetic-visual" data-magnetic-visual>点按确认</span>
    </button>
    <noscript><span class="pc-magnetic-visual">按钮原位</span></noscript>
    <p class="pc-legend">虚线标记按钮原位</p>
  </div>
  <div class="pc-instructions">
    <p>移动鼠标观察按钮偏移。点按按钮,或用键盘确认。</p>
    <p class="pc-status" data-pc-status role="status">等待确认</p>
  </div>
</section>
  </main>
  <script>
const maximumOffset = 12;
const returnDuration = 240;

/** @param {HTMLElement} visual @param {number} x @param {number} y @param {boolean} returning */
function positionNative(visual, x, y, returning) {
  visual.style.transitionDuration = returning ? `${returnDuration}ms` : '0ms';
  visual.style.transform = `translate(${x}px, ${y}px)`;
}

/** @param {HTMLElement} root @param {typeof positionNative} [position] */
function bindMagneticButton(root, position = positionNative) {
  const button = root.querySelector('[data-magnetic-hit]');
  const visual = root.querySelector('[data-magnetic-visual]');
  const status = root.querySelector('[data-pc-status]');
  if (!(button instanceof HTMLButtonElement) || !(visual instanceof HTMLElement) || !status) return;

  const reduced = matchMedia('(prefers-reduced-motion: reduce)');
  let confirmations = 0;
  let frame = 0;
  let clientX = 0;
  let clientY = 0;

  /** @param {number} fraction */
  const offset = (fraction) => maximumOffset * Math.max(-1, Math.min(1, fraction));

  /** @param {PointerEvent} event */
  const follow = (event) => {
    if (event.pointerType !== 'mouse' || reduced.matches) return;
    clientX = event.clientX;
    clientY = event.clientY;
    if (frame) return;
    frame = requestAnimationFrame(() => {
      frame = 0;
      const { left, top, width, height } = button.getBoundingClientRect();
      const x = offset((2 * (clientX - left)) / width - 1);
      const y = offset((2 * (clientY - top)) / height - 1);
      position(visual, x, y, false);
    });
  };
  const returnHome = () => {
    cancelAnimationFrame(frame);
    frame = 0;
    position(visual, 0, 0, !reduced.matches);
  };

  button.addEventListener('pointerenter', follow);
  button.addEventListener('pointermove', follow);
  button.addEventListener('pointerleave', returnHome);
  button.addEventListener('pointercancel', returnHome);
  button.addEventListener('blur', returnHome);
  window.addEventListener('blur', returnHome);
  reduced.addEventListener('change', returnHome);
  button.addEventListener('click', () => {
    confirmations += 1;
    status.textContent = `已确认 · 第 ${confirmations} 次`;
  });
  button.hidden = false;
}


function positionWithGsap(visual, x, y, returning) {
  gsap.killTweensOf(visual);
  if (returning) gsap.to(visual, { x, y, duration: returnDuration / 1000, ease: 'expo.out' });
  else gsap.set(visual, { x, y });
}

const demo = document.querySelector('[data-pointer-comparison]');
bindMagneticButton(demo, window.gsap ? positionWithGsap : undefined);
  </script>
<script>
(() => {
/** @param {number} duration @param {AbortSignal} signal @param {(progress: number) => void} [render] */
function guideBeat(duration, signal, render) {
  if (signal.aborted) return Promise.resolve();
  if (duration === 0) {
    render?.(1);
    return Promise.resolve();
  }

  return new Promise((resolve) => {
    let timer = 0;
    let frame = 0;
    const done = () => {
      clearTimeout(timer);
      cancelAnimationFrame(frame);
      signal.removeEventListener('abort', done);
      resolve(undefined);
    };
    signal.addEventListener('abort', done, { once: true });
    if (!render) {
      timer = window.setTimeout(done, duration);
      return;
    }

    const start = performance.now();
    const tick = (now) => {
      const progress = Math.min(1, (now - start) / duration);
      render(progress);
      if (progress === 1) done();
      else if (!signal.aborted) frame = requestAnimationFrame(tick);
    };
    frame = requestAnimationFrame(tick);
  });
}

/** @param {HTMLElement} root @param {import('./demo-guide-cases').DemoGuide} guide */
function bindDemoGuide(root, guide) {
  const view = root.querySelector(guide.view);
  if (!view || root.dataset.guideState || guide.steps.some(({ target }) => !root.querySelector(target))) return;

  const dock = guide.dock ? root.querySelector(guide.dock) : null;
  const bar = document.createElement('div');
  bar.className = 'demo-guide';
  bar.innerHTML = '<p data-guide-caption></p><button type="button" data-guide-replay>重播导览</button>';
  const caption = bar.querySelector('[data-guide-caption]');
  const replay = bar.querySelector('button');
  const heading = root === document.body ? root.querySelector('h1') : null;
  if (dock) dock.prepend(bar);
  else if (heading) heading.after(bar);
  else root.prepend(bar);

  const cursor = document.createElement('div');
  cursor.className = 'demo-guide-cursor';
  cursor.setAttribute('aria-hidden', 'true');
  cursor.hidden = true;
  cursor.innerHTML = '<svg viewBox="0 0 20 24" focusable="false"><path d="M2 2v17l4.8-4.5L10 21l3.2-1.6-3.2-6.2 6.6-.7L2 2Z" fill="#222c36" stroke="#fff" stroke-width="1.5" stroke-linejoin="round"/></svg>';
  document.body.append(cursor);

  const reduced = matchMedia('(prefers-reduced-motion: reduce)');
  const threshold = .5;
  const idleCaption = '导览在画面进入视口后播放一次。';
  const reducedCaption = '可重播关键状态,或直接操作。';
  const reset = guide.reset ? (root.matches(guide.reset) ? root : root.querySelector(guide.reset)) : null;
  const releaseTarget = guide.release ? root.querySelector(guide.release) : null;
  let autoPending = !reduced.matches;
  let inView = false;
  let playbackScroll = window.scrollY;
  /** @type {AbortController | undefined} */
  let run;
  /** @type {[number, number] | undefined} */
  let cursorPosition;

  root.dataset.guideState = 'idle';
  caption.textContent = reduced.matches ? reducedCaption : idleCaption;

  function hideCursor() {
    cursor.hidden = true;
    delete cursor.dataset.press;
    cursorPosition = undefined;
  }

  /** @param {PointerEvent} [pointer] */
  function stop(pointer) {
    autoPending = false;
    if (!run) return;
    run.abort();
    run = undefined;
    hideCursor();
    if (releaseTarget) {
      // A real pointer inside the target keeps its hover when the guide yields.
      if (pointer) sendPointer(releaseTarget, 'pointerenter', [pointer.clientX, pointer.clientY]);
      else sendPointer(releaseTarget, 'pointerleave', [0, 0]);
    }
    reset?.dispatchEvent(new Event('formtempo:guide-cancel'));
    root.dataset.guideState = 'interrupted';
    caption.textContent = '导览已停止,可以继续手动操作。';
  }

  /** @param {[number, number]} position */
  function moveCursor(position) {
    cursor.hidden = false;
    cursor.style.transform = `translate3d(${position[0]}px, ${position[1]}px, 0)`;
    cursorPosition = position;
  }

  /** @param {Element} target @param {readonly [number, number]} point */
  function location(target, [x, y]) {
    const rect = target.getBoundingClientRect();
    return /** @type {[number, number]} */ ([rect.left + rect.width * x, rect.top + rect.height * y]);
  }

  /** @param {Element} target @param {string} type @param {readonly [number, number]} position */
  function sendPointer(target, type, [clientX, clientY]) {
    target.dispatchEvent(new PointerEvent(type, { pointerType: 'mouse', clientX, clientY }));
  }

  /** @param {HTMLInputElement} slider @param {number} value */
  function setProgress(slider, value) {
    const next = Math.round(value);
    if (slider.valueAsNumber === next) return;
    slider.value = String(next);
    slider.dispatchEvent(new Event('input', { bubbles: true }));
  }

  /** @param {number} value */
  function showReducedProgress(value) {
    const options = Array.from(root.querySelectorAll('button[data-driven-step], button[data-scale-step], button[data-progress-step], button[data-progress]'));
    const percent = (button) => button.hasAttribute('data-progress')
      ? Number(button.getAttribute('data-progress')) * 100
      : Number(button.getAttribute('data-driven-step') ?? button.getAttribute('data-scale-step') ?? button.getAttribute('data-progress-step'));
    options.sort((a, b) => Math.abs(percent(a) - value) - Math.abs(percent(b) - value));
    if (options[0] instanceof HTMLButtonElement) options[0].click();
  }

  /** @param {import('./demo-guide-cases').DemoGuide['steps'][number]} step @param {AbortSignal} signal */
  async function playStep(step, signal) {
    const target = root.querySelector(step.target);
    if (!target) return;
    caption.textContent = step.text;
    const { action, value = 0, point = [.5, .5] } = step;

    if (action === 'progress' && target instanceof HTMLInputElement) {
      if (reduced.matches) {
        showReducedProgress(value);
      } else {
        const from = target.valueAsNumber;
        await guideBeat(step.duration ?? 0, signal, (progress) => {
          const current = from + (value - from) * progress;
          setProgress(target, current);
          moveCursor(location(target, [.04 + .92 * current / 100, .65]));
        });
      }
    } else {
      if (!reduced.matches) {
        const to = location(target, point);
        const [x, y] = point;
        const entry = x < .25 ? [-.08, y] : x > .75 ? [1.08, y] : [x, y < .5 ? -.08 : 1.08];
        const from = action === 'enter' ? location(target, /** @type {[number, number]} */ (entry))
          : cursorPosition ?? [to[0] + 26, to[1] + 19];
        const duration = action === 'leave' ? 200 : 340;
        await guideBeat(duration, signal, (progress) => {
          const t = 1 - (1 - progress) ** 3;
          const end = location(target, point);
          const position = /** @type {[number, number]} */ ([
            from[0] + (end[0] - from[0]) * t,
            from[1] + (end[1] - from[1]) * t,
          ]);
          moveCursor(position);
          if (action === 'move') sendPointer(target, 'pointermove', position);
        });
      }
      if (signal.aborted) return;

      if (action === 'click' && target instanceof HTMLElement) {
        if (!reduced.matches) {
          cursor.dataset.press = '';
          await guideBeat(125, signal);
          if (signal.aborted) return;
        }
        target.click();
        delete cursor.dataset.press;
      } else if (action === 'enter' || action === 'leave') {
        sendPointer(target, `pointer${action}`, location(target, point));
      }
    }

    await guideBeat(reduced.matches ? 600 : step.hold ?? 500, signal);
  }

  function bringViewIntoFrame() {
    const rect = view.getBoundingClientRect();
    const visibleHeight = Math.min(rect.bottom, window.innerHeight) - Math.max(rect.top, 0);
    if (visibleHeight < rect.height * threshold) view.scrollIntoView({ block: 'center', behavior: 'instant' });
  }

  async function start(replaying = false) {
    stop();
    const controller = new AbortController();
    const { signal } = controller;
    run = controller;
    root.dataset.guideState = 'playing';

    if (guide.ready) {
      caption.textContent = '正在等待视频就绪…';
      const deadline = performance.now() + 4000;
      while (!signal.aborted && !root.querySelector(guide.ready) && performance.now() < deadline &&
        !root.querySelector('[data-video-state="error"]')) {
        await guideBeat(90, signal);
      }
      if (signal.aborted) return;
      if (!root.querySelector(guide.ready)) {
        run = undefined;
        root.dataset.guideState = 'unavailable';
        caption.textContent = '视频暂未就绪,可以查看关键帧或重播。';
        return;
      }
    }

    reset?.dispatchEvent(new Event('formtempo:guide-reset'));
    if (replaying) bringViewIntoFrame();
    playbackScroll = window.scrollY;
    const steps = (reduced.matches && guide.reducedSteps) || guide.steps;
    for (const step of steps) {
      if (signal.aborted) return;
      await playStep(step, signal);
    }
    if (signal.aborted) return;

    run = undefined;
    hideCursor();
    root.dataset.guideState = 'complete';
    caption.textContent = '导览结束,可以继续手动操作。';
  }

  function tryAutoplay() {
    if (autoPending && inView && !document.hidden) void start();
  }

  if (typeof IntersectionObserver === 'function') {
    const observer = new IntersectionObserver(([entry]) => {
      inView = entry.intersectionRatio >= threshold;
      if (!entry.isIntersecting && run) stop();
      tryAutoplay();
    }, { threshold: [0, threshold] });
    observer.observe(view);
  }

  replay.addEventListener('click', () => {
    bringViewIntoFrame();
    void start(true);
  });

  const takeOver = (event) => {
    if (!event.isTrusted || replay.contains(event.target)) return;
    if (!run) {
      if (event.type === 'wheel' || !(event.target instanceof Element)) return;
      if (!event.target.closest('button, input') && !view.contains(event.target)) return;
    }
    const pointer = event instanceof PointerEvent && event.pointerType === 'mouse' && releaseTarget?.contains(event.target)
      ? event : undefined;
    stop(pointer);
  };
  for (const event of ['pointerdown', 'keydown', 'focusin', 'input', 'click', 'wheel']) {
    root.addEventListener(event, takeOver, { capture: true, passive: true });
  }
  if (guide.steps.some(({ action }) => action === 'enter' || action === 'move')) {
    view.addEventListener('pointermove', takeOver, { capture: true, passive: true });
  }
  if (guide.pageScrollInput) {
    window.addEventListener('scroll', () => {
      if (run && window.scrollY !== playbackScroll) stop();
    }, { passive: true });
  }
  document.addEventListener('visibilitychange', () => {
    if (document.hidden && run) stop();
    else tryAutoplay();
  });
  reduced.addEventListener('change', () => {
    if (!reduced.matches) return;
    const wasIdle = root.dataset.guideState === 'idle';
    stop();
    if (wasIdle) caption.textContent = reducedCaption;
  });
}

bindDemoGuide(document.body, {"view":"[data-magnetic-hit]","release":"[data-magnetic-hit]","reducedSteps":[{"target":"[data-magnetic-hit]","action":"click","text":"减少动态效果时,按钮保持原位,仍可点按确认。"}],"steps":[{"target":"[data-magnetic-hit]","action":"move","text":"指针靠左时,按钮视觉层向左偏移。","point":[0.12,0.45],"hold":360},{"target":"[data-magnetic-hit]","action":"move","text":"移向右下角,按钮跟着偏移。","point":[0.88,0.8],"hold":360},{"target":"[data-magnetic-hit]","action":"leave","text":"离开热区,按钮回到虚线标出的原位。","point":[1.15,0.85]}]});
})();
</script>
</body>
</html>