Guillaume follows an Entity-Component-System (ECS) architecture to separate state, behavior, and orchestration.

Core Concepts

• Entity: A uniquely identified object in the scene graph (button, text, icon).
• Component: Data attached to an entity (transform, bounds, text content, etc.).
• System: Logic that processes entities matching a component signature.

This design makes the framework easier to extend and maintain.

Components

• Transform: Position, orientation, and scale.
• Bounds: Width and height.
• Color: Fill or display color.
• Border: Border color and thickness.
• Text: Label content and font properties.
• Click: Click callback and click-related state.
• Hover: Hover callback and hover-related state.
• Focus: Focus gain/loss behavior.
• Icon: Icon identifier and rendering metadata.

Systems

• RectangleRender: Draws rectangle-based entities.
• TextRender: Draws text entities.
• IconRender: Draws icon entities.
• Interaction: Handles click, hover, and focus events.
• KeyboardControl: Handles keyboard interactions.
• MeasureText: Computes text bounds and updates Bounds.

Entity Hierarchy

Entities can own child entities. This enables composition patterns such as a button containing both text and icon children.