Build the destination route using PageRouteBuilder.

Flying a hero from one route to another as it transforms
from a circular shape to a rectangular shape is a slick
effect that you can implement using Hero widgets.
To accomplish this, the code animates the intersection of
two clip shapes: a circle and a square.
Throughout the animation, the circle clip (and the image)
scales from minRadius to maxRadius, while the square
clip maintains constant size. At the same time,
the image flies from its position in the source route to its
position in the destination route. For visual examples
of this transition, see Radial transformation
in the Material motion spec.

This animation might seem complex (and it is), but you can customize the
provided example to your needs. The heavy lifting is done for you.

Radial hero animation code

Each of the following examples demonstrates a radial hero animation.
  This guide describes the first example.

radial_hero_animation