performLayout method

@override Size performLayout(BoxConstraints constraints)

Hook for subclasses to perform layout within the given constraints.

Implementation

@override
Size performLayout(BoxConstraints constraints) {
  final win = widget as Window;
  final width = win.width;
  final height = win.height;

  if (childElement != null) {
    childElement!.relativeOffset = const Offset(1, 1);
    final childW = max(0, width - 2);
    final childH = max(0, height - 2);
    childElement!.layout(BoxConstraints.tight(Size(childW, childH)));
  }

  return constraints.constrain(Size(width, height));
}