A Pannya UI is just a tree of nodes. Each node stores state (position, size, input flags, etc.) and can be extended with custom logic. The engine takes care of the rest.

Responsibilities

• Nodes: Containers with fields and overridable methods.
• Engine: Active manager that handles:
  • Layout updates
  • Input dispatch (mouse, keyboard, focus)
  • Update and draw loops

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What Not To Do

1. Don’t directly modify fields like x, y, width, or height.
   • Use setters, or call invalidateAxis(Node.Axis.?) after direct modification.
2. Don’t add nodes to a parent inside the update() method. Nodes themselves can add children to self anywhere they want.