none static method
Does not perform any shifting if the follower overflows out of the viewport.
Implementation
static Offset none(Size view, FPortalTarget target, FPortalFollower follower) {
final targetAnchor = target.anchor.relative(to: target.size);
final followerAnchor = follower.anchor.relative(to: follower.size);
return targetAnchor - followerAnchor;
}