meshcore-open/lib/utils/route_transitions.dart

import 'package:flutter/material.dart';

Route<T> buildQuickSwitchRoute<T>(Widget page) {
  return PageRouteBuilder<T>(
    pageBuilder: (context, animation, secondaryAnimation) => page,
    transitionDuration: const Duration(milliseconds: 220),
    reverseTransitionDuration: const Duration(milliseconds: 200),
    transitionsBuilder: (context, animation, secondaryAnimation, child) {
      // Pure crossfade — no positional slide, so the shared top chrome
      // (app bar + Contacts/Channels toggle) stays rock-steady while switching.
      return FadeTransition(
        opacity: CurvedAnimation(
          parent: animation,
          curve: Curves.easeOut,
          reverseCurve: Curves.easeIn,
        ),
        child: child,
      );
    },
  );
}