NodeShape class abstract

Defines the visual shape and appearance of a node in the flow editor.

A NodeShape determines how a node appears visually by providing:

• A Path that defines the node's outline
• Port anchor points that define where ports attach to the shape
• Visual properties like fill color, stroke color, and stroke width
• Hit testing logic to determine if a point is inside the shape

This abstraction allows nodes to be rendered as various shapes like circles, diamonds, hexagons, etc., instead of just rectangles.

Shapes are typically created in the nodeContainerBuilder based on node type or data, keeping the node model purely data-focused.

Example:

nodeContainerBuilder: (context, node) {
  NodeShape? shape;
  if (node.type == 'Decision') {
    shape = DiamondShape(
      fillColor: Colors.orange,
      strokeColor: Colors.deepOrange,
      strokeWidth: 2.0,
    );
  }
  return NodeWidget(node: node, shape: shape, child: ...);
}