Into which architectural layers is Flutter divided…

Flutter is divided into the following architectural layers:

Embedder: Responsible for interacting with the operating system. It provides platform-specific entry points for rendering surfaces, access to accessibility services, user input, and lifecycle management. The Embedder is written in a language suitable for the specific platform (Java for Android, Objective-C/Swift for iOS, C++ for Windows/Linux/macOS).
Engine: The core of the framework. Mainly implemented in C/C++. It provides low-level functionality: Skia (2D graphics library), Text (text handling library), IO (input/output), Dart Runtime, Flutter Engine (task scheduling, rendering management, compositing).
Framework: Written in Dart. This is the Dart API that Flutter developers interact with directly. It consists of several levels:
- Foundation: Basic classes and utilities.
- Widgets: The foundation of UI in Flutter. Widgets describe the configuration of interface elements.
- Rendering: Abstractions for rendering, providing low-level objects for building rendering trees.
- Painting, Gestures, Animation, etc.: Levels that provide functionality for drawing, gesture handling, animation, etc.
- Material/Cupertino Libraries: Widget sets implementing Material Design and iOS Cupertino design systems.

Here is a simplified representation of the hierarchy:

[Your Application Code (Dart Widgets)]
        |
    [Framework (Dart)]
        |
    [Engine (C/C++)]
      /        \
[Embedder]    [Skia]
   |            |
[Operating System]

The Embedder launches the Engine, which provides the Dart Runtime and API. The Framework, written in Dart, interacts with the Engine via the Dart API. Your application code uses Framework widgets to build the user interface. The Engine, in turn, uses Skia for rendering elements on the Canvas provided by the Embedder.

Into which architectural layers is Flutter divided?