🐛 [firebase_performance] Screen Rendering

[FMorschel]

Screen Rendering

Some packages like https://pub.dev/packages/show_fps are out there, and they do a really interesting workaround to track FPS on the current Widget.

I don't know how this is handled, but could the API for the screen rendering be exposed on the package so that the actual developers could use something like this to track it? Or a mixin could be created like:

// Similar to what's calculated on `show_fps`
mixin FPSStateMixin<W extends StatefulWidget> on State<W> {
  Duration? _previous;
  Duration? _timing;

  @override
  void initState() {
    SchedulerBinding.instance.addPostFrameCallback(update);
    super.initState();
  }

  void update(Duration duration) {
    if (mounted && (ModalRoute.of(context)?.isCurrent ?? false)) {
      if (_previous != null) {
        _timing = duration - _previous!;
      }
      _previous = duration;
      if (_timing != null) {
        final fps = 1000 / _timing!.inMilliseconds;
        // Send the FPS data to Firebase Performance.
      }
      SchedulerBinding.instance.addPostFrameCallback(update);
    }
  }
}

[darshankawar]

Thanks for the report @FMorschel
Per documentation:

On Flutter, automatic screen rendering performance monitoring is not possible for individual Flutter screens. A single view controller encapsulates your entire Flutter application natively so the underlying native Firebase SDK is not aware of screen transitions.

Does this help to answer your question ?

[FMorschel]

I'm aware of that documentation. I only wanted to ask here if you could expose an API for warning about screen transitions or even implement it with a RouteObserver like firebase_analytics.

[darshankawar]

Thanks for the feedback. Keeping it open for team's attention / tracking.