08Hiệu ứng chữ viết tay SVG

<main class="stage">
  <div class="sig">
    <svg class="sig__svg" viewBox="0 0 240 80" fill="none" aria-hidden="true">
      <path d="M10 60 C 30 10, 50 70, 70 30 S 110 10, 130 50 S 170 70, 190 20 S 220 40, 230 30" />
    </svg>
    <p class="sig__label">Vui lòng ký tên</p>
  </div>
</main>

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

$duration: $dur-loop;                      // 획을 그리는 한 루프
$easing: $ease-out;                        // 손으로 긋는 듯 빠르게 시작해 부드럽게 끝난다
$color: $subject-blue;                     // 선 색

@include stage($stage-paper);

.sig {
  display: grid;
  justify-items: center;
  gap: clamp(6px, 2vw, 12px);

  &__svg {
    width: min(260px, 82vw);
    height: auto;

    path {
      stroke: $color;
      stroke-width: 5;
      stroke-linecap: round;
      stroke-linejoin: round;
      stroke-dasharray: 520;
      stroke-dashoffset: 520;
      animation: draw $duration $easing infinite;
    }
  }

  &__label {
    margin: 0;
    font-weight: 700; font-size: clamp(14px, 4vw, 18px); line-height: 1.4; font-family: inherit;
    color: $stage-ink;
  }
}

@keyframes draw {
  0%, 6%    { stroke-dashoffset: 520; }
  55%       { stroke-dashoffset: 0; }
  80%       { stroke-dashoffset: 0; }
  96%, 100% { stroke-dashoffset: 520; }
}

@media (prefers-reduced-motion: reduce) {
  .sig__svg path { animation: none; stroke-dashoffset: 0; }
}

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);
}

.sig {
  display: grid;
  justify-items: center;
  gap: clamp(6px, 2vw, 12px);
}
.sig__svg {
  width: min(260px, 82vw);
  height: auto;
}
.sig__svg path {
  stroke: #2f6df6;
  stroke-width: 5;
  stroke-linecap: round;
  stroke-linejoin: round;
  stroke-dasharray: 520;
  stroke-dashoffset: 520;
  animation: draw 2s ease-out infinite;
}
.sig__label {
  margin: 0;
  font-weight: 700;
  font-size: clamp(14px, 4vw, 18px);
  line-height: 1.4;
  font-family: inherit;
  color: #17141a;
}

@keyframes draw {
  0%, 6% {
    stroke-dashoffset: 520;
  }
  55% {
    stroke-dashoffset: 0;
  }
  80% {
    stroke-dashoffset: 0;
  }
  96%, 100% {
    stroke-dashoffset: 520;
  }
}
@media (prefers-reduced-motion: reduce) {
  .sig__svg path {
    animation: none;
    stroke-dashoffset: 0;
  }
}

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

export type HandwritingSvgProps = {
  label: string;
  /** 획을 그리는 한 루프 (기본 2000ms) */
  duration?: number;
  color?: string;
};

export default function HandwritingSvg({ label, duration = 2000, color = "#2f6df6" }: HandwritingSvgProps) {
  const vars = { "--duration": `${duration}ms`, "--color": color } as CSSProperties;
  return (
    <div className={styles.sig} style={vars}>
      <svg className={styles.svg} viewBox="0 0 240 80" fill="none" aria-hidden="true">
        <path d="M10 60 C 30 10, 50 70, 70 30 S 110 10, 130 50 S 170 70, 190 20 S 220 40, 230 30" />
      </svg>
      <p className={styles.label}>{label}</p>
    </div>
  );
}