# ForceDirectedLayoutAlgorithm

Import it from `@grafloria/engine`.

Also has every member of `BaseLayoutAlgorithm`, listed on its own entry.

ForceDirectedLayoutAlgorithm

Physics-based layout where:
- Nodes repel each other (like magnets with same poles)
- Connected nodes attract each other (like springs)
- System settles into equilibrium over iterations

Best for:
- Network diagrams
- Social graphs
- Relationship visualizations
- Organic, natural-looking layouts

```ts
class ForceDirectedLayoutAlgorithm extends BaseLayoutAlgorithm implements ILayoutAlgorithm
```

**Methods**

- `constructor(options?: ForceDirectedOptions)`
- `getName(): string` — Get the name of the layout algorithm
- `getType(): 'force-directed'` — Get the type of the layout algorithm
- `override configure(config: LayoutConfiguration): void` — Configure the layout algorithm
- `override getConfiguration(): LayoutConfiguration` — Get current configuration
- `override canApply(diagram: DiagramModel): { valid: boolean; reason?: string }` — Validate if this algorithm can be applied to the given diagram

For example:
- Hierarchical layout requires a DAG (no cycles)
- Force-directed works better with connected nodes
- `calculatePlacement(options: PlacementOptions): PlacementResult` — Calculate position for a single new node

This is called when a node is added to the diagram. The algorithm should return a position that:
- Doesn't overlap with existing nodes
- Follows the layout strategy
- Fits within the viewport (or is close to existing content)
- `reLayout(diagram: DiagramModel, config?: LayoutConfiguration): Map<string, Point>` — Re-layout all nodes in the diagram

This is called when the user explicitly requests a re-layout (e.g., clicks "Re-Arrange" button). The algorithm should calculate new positions for ALL nodes.
- `onActivate(): void` — Called when the algorithm is activated
Use this to initialize any state or caches
- `onDeactivate(): void` — Called when the algorithm is deactivated
Use this to clean up state or caches