shape property
final
The OutlinedBorder of the scrollbar's thumb.
Only one of radius and shape may be specified. For a rounded rectangle, it's simplest to just specify radius. By default, the scrollbar thumb's shape is a simple rectangle.
If shape is specified, the thumb will take the shape of the passed OutlinedBorder and fill itself with thumbColor (or grey if it is unspecified).
link
To create a local project with this code sample, run:
flutter create --sample=widgets.RawScrollbar.shape.1 mysample
Implementation
final OutlinedBorder? shape;