import 'package:meta/meta.dart' show immutable; @immutable class OptionalSize { const OptionalSize( this.width, this.height, ); /// If non-null, requires the child to have exactly this width. /// If null, the child is free to choose its own width. final double? width; /// If non-null, requires the child to have exactly this height. /// If null, the child is free to choose its own height. final double? height; OptionalSize copyWith({ double? width, double? height, }) { return OptionalSize( width ?? this.width, height ?? this.height, ); } }