toJson method
Implementation
Map<String, dynamic> toJson() => {
'line_type': lineType.index,
'arrow_type': arrowType.index,
'back_arrow_type': backArrowType.index,
'arrow_size': arrowSize,
'back_arrow_size': backArrowSize,
'line_width': lineWidth,
'color': color.toString().split('(0x')[1].split(')')[0],
};