toJson method
Serializes this viewport to JSON.
Returns a map suitable for JSON encoding containing x, y, and zoom values.
Example:
final viewport = GraphViewport(x: 100, y: 50, zoom: 1.5);
final json = viewport.toJson();
// Returns: {'x': 100.0, 'y': 50.0, 'zoom': 1.5}
Implementation
Map<String, dynamic> toJson() => {'x': x, 'y': y, 'zoom': zoom};