toMap method 
    
    
    
  Implementation
  @override
Map<String, dynamic> toMap() {
  final Map<String, dynamic> json = {
    'brush': _brush?.toMap(),
    'selectedBrush': _selectedBrush?.toMap(),
    'statusIconStyle': _statusIconStyle?.toMap(),
  };
  if (_iconBase64 != null) {
    json['icon'] = _iconBase64;
  }
  if (_selectedIconBase64 != null) {
    json['selectedIcon'] = _selectedIconBase64;
  }
  if (_iconScandit != null) {
    json['icon'] = _iconScandit?.toMap();
  }
  if (_selectedIconScandit != null) {
    json['selectedIcon'] = _selectedIconScandit?.toMap();
  }
  json.removeWhere((key, value) => value == null);
  return json;
}