src/animations/blink.js


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import { sineOut } from 'svelte/easing';

export const blink = function blink(node, params) {

  const originalWidth = parseFloat(getComputedStyle(node).width);
  const originalHeight = parseFloat(getComputedStyle(node).height);

  return {
    delay: params.delay || 0,
    duration: params.duration || 400,
    easing: params.easing || sineOut,
    css: (t, u) => {

      const halfWidth = originalWidth / 2;
      const halfHeight = originalHeight / 2;
      // const padding = t < 0.8 ? halfWidth * (1 - t) / 0.8 : halfWidth / 2 + 1;
      const height = Math.round(t <= 0.2 ? (originalHeight * t) / 0.2 : originalHeight);
      const marginY = Math.round(t <= 0.2 ? halfHeight * (1 - t / 0.2) : 0);
      const width = Math.round(t > 0.2 ? ((t - 0.2) / 0.8) * originalWidth : 0);
      const marginX = Math.round(t > 0.2 ? (1 - (t - 0.2) / 0.8) * halfWidth : halfWidth);

      return `width: ${width}px; height: ${height}px; margin: ${marginY}px ${marginX}px`;
    }
  };
};