JS を使用してカラー 10 進数を rgba 形式に変換する方法の詳細なチュートリアル

function getColor(number) {
  let color = number;
  const blue = parseInt(color % 0x100, 10);
  color = color >>> 8;
  const green = parseInt(color % 0x100, 10);
  color = color >>> 8;
  const red = parseInt(color % 0x100, 10);
  const alpha = (parseInt(color >>> 8, 10) / 0xFF).toFixed(1);
  return `rgba(${red}, ${green}, ${blue}, ${alpha})`;
}

function getColor(number) {
  const alpha = number >> 24 & 0xff;
  const red = number >> 16 & 0xff;
  const green = number >> 8 & 0xff;
  const blue = number & 0xff;
  return `rgba(${red}, ${green}, ${blue}, ${alpha})`;
}