Col constructor

const Col({
  1. Key? key,
  2. required List<Widget> children,
  3. Widget widgetCallback(
    1. Widget widget
    )?,
  4. Color? backgroundColor,
  5. MainAxisSize? mainAxisSize,
  6. MainAxisAlignment? mainAxisAlignment,
  7. CrossAxisAlignment? crossAxisAlignment,
  8. EdgeInsetsGeometry? margin,
  9. EdgeInsetsGeometry? padding,
})

引数のウィジェットリスト（children）を元にコンテナウィジェットを返す ウィジェットリストをラップするコンテナの背景色は透明、枠付き（薄灰色）、余白(padding)は2 _widgetCallback引数を利用することで個別のラッパー処理が可能（デフォルトはPadding:2でラップ）

Implementation

const Col({
  super.key,
  required this.children,
  Widget Function(Widget widget)? widgetCallback,
  Color? backgroundColor,
  MainAxisSize? mainAxisSize,
  MainAxisAlignment? mainAxisAlignment,
  CrossAxisAlignment? crossAxisAlignment,
  EdgeInsetsGeometry? margin,
  EdgeInsetsGeometry? padding,
})  : backgroundColor =
          backgroundColor ?? const Color.fromARGB(255, 180, 180, 180),
      padding = padding ?? const EdgeInsets.all(2),
      margin = margin ?? const EdgeInsets.all(2),
      mainAxisSize = mainAxisSize ?? MainAxisSize.max,
      mainAxisAlignment = mainAxisAlignment ?? MainAxisAlignment.start,
      crossAxisAlignment = crossAxisAlignment ?? CrossAxisAlignment.center,
      widgetCallback = widgetCallback ?? _widgetCallback;