Roll constructor
Creates a Roll that can provide gradient and animation properties to descendant Foil widgets.
The gradient
parameter specifies a shared gradient that descendant Foil
widgets can use if they don't specify their own.
The crinkle
parameter (defaults to Crinkle.smooth) provides animation
properties that affect how descendant Foil widgets animate their gradients.
This animation works independently from pointer tracking.
The child
parameter is the widget below this widget in the tree.
Implementation
const Roll({
Key? key,
this.gradient,
this.crinkle = Crinkle.smooth,
this.child,
}) : super(key: key);