Flutter - How to replace Flutter widgets with canvas and vis versa

I have a fairly odd problem I'm trying to solve. I'm making a 2D game using Flutter Flame. The library uses a canvas, as seen here:

start() {
var previous = Duration.ZERO;

window.onBeginFrame = (now) {
var recorder = new PictureRecorder();
var canvas = new Canvas(
recorder,
new Rect.fromLTWH(
0.0, 0.0, window.physicalSize.width, window.physicalSize.height));

Duration delta = now - previous;
if (previous == Duration.ZERO) {
delta = Duration.ZERO;
}
previous = now;

var t = delta.inMicroseconds / Duration.MICROSECONDS_PER_SECOND;

update(t);
render(canvas);

var deviceTransform = new Float64List(16)
..[0] = window.devicePixelRatio
..[5] = window.devicePixelRatio
..[10] = 1.0
..[15] = 1.0;

var builder = new SceneBuilder()
..pushTransform(deviceTransform)
..addPicture(Offset.zero, recorder.endRecording())
..pop();

window.render(builder.build());
window.scheduleFrame();
};

window.scheduleFrame();
}


It's worth noting that Flutter Flame uses a custom BindingBase, similar to how the Widgets work.

class _CustomBinder extends BindingBase with ServicesBinding {}


This works great for the game, but I was hoping to use real flutter widgets for the main menu, settings pages, etc.

Is there a way to swap between these two contexts?

To provide an idea of what I'm looking for, I'd like there to exist these two functions:

loadHomeScreen(); // replaces the canvas, if any, with Flutter widgets
loadCanvasScene(); // replaces the Flutter widgets with the canvas


In the newer versions of Flame (0.8.x), the game becomes a regular Widget, and thus support for apps that have regular widgets for menus and settings.

Start as a regular app, and in one of your build methods, add the widget of your game implementation:

class MyGame extends BaseGame {
// your game here
}

// in your game screen class

final MyGame game = new MyGame();

@override
Widget build(BuildContext context) {
return game.widget;
}


For a more in-depth example, check this complete game, built using the latest version of Flame. The specific code you are looking for, that switches between game and app is here.