toJson method
Implementation
Map<String, dynamic> toJson() => {
'size': '${area.width}*${area.height}',
'position': '${position.x},${position.y}',
'basePosition': '${basePosition.x},${basePosition.y}',
'velocity': '${velocity.x},${velocity.y}',
'radius': radius,
'baseRadius': baseRadius,
};