08Two-tone sweep

<main class="stage">
  <div class="sweep">
    <span class="sweep__base" data-split>Half-Price Sale</span>
    <span class="sweep__top" aria-hidden="true" data-split>Half-Price Sale</span>
  </div>
</main>

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

$duration: $dur-loop;
$easing: $ease-spring;
$base: $subject-ink;                               // 아래 색
$sweep: $subject-blue;                              // 위에서 걷히는 색

@include stage($stage-paper);

.sweep {
  position: relative;
  font-weight: 800; font-size: clamp(26px, 8.4vw, 42px); line-height: 1.2; font-family: inherit;
}

.sweep__base, .sweep__top {
  display: block;
  margin: 0;
  text-align: center;
}

.sweep__base { color: $base; }

.sweep__top {
  position: absolute;
  inset: 0;
  color: $sweep;
  animation: sweep-wipe $duration $easing infinite;
}

.sweep .letter {
  display: inline-block;
  animation: letter-blur-in $duration $easing infinite;
  animation-delay: calc(var(--i) * 30ms + var(--n) * 50ms);
}

@keyframes sweep-wipe {
  0%, 4%    { clip-path: inset(0 100% 0 0); }
  40%, 62%  { clip-path: inset(0 0 0 0); }
  96%, 100% { clip-path: inset(0 100% 0 0); }
}

@keyframes letter-blur-in {
  0%, 2%    { filter: blur(9px); }
  14%, 100% { filter: blur(0); }
}

@media (prefers-reduced-motion: reduce) {
  .sweep__top { animation: none; clip-path: inset(0 0 0 0); }
  .sweep .letter { animation: none; filter: none; }
}

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

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

.sweep {
  position: relative;
  font-weight: 800;
  font-size: clamp(26px, 8.4vw, 42px);
  line-height: 1.2;
  font-family: inherit;
}

.sweep__base, .sweep__top {
  display: block;
  margin: 0;
  text-align: center;
}

.sweep__base {
  color: #17141a;
}

.sweep__top {
  position: absolute;
  inset: 0;
  color: #2f6df6;
  animation: sweep-wipe 2s cubic-bezier(0.2, 0.8, 0.2, 1) infinite;
}

.sweep .letter {
  display: inline-block;
  animation: letter-blur-in 2s cubic-bezier(0.2, 0.8, 0.2, 1) infinite;
  animation-delay: calc(var(--i) * 30ms + var(--n) * 50ms);
}

@keyframes sweep-wipe {
  0%, 4% {
    clip-path: inset(0 100% 0 0);
  }
  40%, 62% {
    clip-path: inset(0 0 0 0);
  }
  96%, 100% {
    clip-path: inset(0 100% 0 0);
  }
}
@keyframes letter-blur-in {
  0%, 2% {
    filter: blur(9px);
  }
  14%, 100% {
    filter: blur(0);
  }
}
@media (prefers-reduced-motion: reduce) {
  .sweep__top {
    animation: none;
    clip-path: inset(0 0 0 0);
  }
  .sweep .letter {
    animation: none;
    filter: none;
  }
}

(function(){
  function splitLetters(el){
    var text = el.textContent;
    el.textContent = "";
    Array.from(text).forEach(function(ch, i){
      var span = document.createElement("span");
      span.className = "letter";
      var seed = Math.sin((i + 1) * 12.9898) * 43758.5453;
      var noise = seed - Math.floor(seed);
      span.style.setProperty("--i", i);
      span.style.setProperty("--n", noise.toFixed(3));
      span.textContent = ch === " " ? " " : ch;
      el.appendChild(span);
    });
  }
  document.querySelectorAll("[data-split]").forEach(splitLetters);
})();

import type { CSSProperties } from "react";
import styles from "./TwoToneSweep.module.scss";

type Vars = CSSProperties & { "--i"?: number; "--n"?: number };

function noise(i: number): number {
  const s = Math.sin((i + 1) * 12.9898) * 43758.5453;
  return Number((s - Math.floor(s)).toFixed(3));
}

export type TwoToneSweepProps = {
  text: string;
  /** 스윕 한 주기 (기본 2000ms) */
  duration?: number;
  base?: string;
  sweep?: string;
};

export default function TwoToneSweep({ text, duration = 2000, base = "#17141a", sweep = "#2f6df6" }: TwoToneSweepProps) {
  const vars = { "--duration": `${duration}ms`, "--base": base, "--sweep": sweep } as CSSProperties;
  const chars = Array.from(text);
  const renderLetters = () =>
    chars.map((ch, i) => (
      <span key={i} className={styles.letter} style={{ "--i": i, "--n": noise(i) } as Vars}>
        {ch === " " ? " " : ch}
      </span>
    ));
  return (
    <div className={styles.sweep} style={vars}>
      <span className={styles.base}>{renderLetters()}</span>
      <span className={styles.top} aria-hidden="true">{renderLetters()}</span>
    </div>
  );
}