fis_lib_business_components/lib/components/white_board/structure.dart

import 'dart:math';
import 'dart:ui';

import 'package:flutter/material.dart';

/// 数据类型定义

/// 绘制类型：直线、曲线
enum PaintType { straightLine, curvedLine }

/// 绘制状态：正在绘制、已完成、隐藏
enum PaintState { doing, done, hide }

/// Point 点类
class Point {
  final double x;
  final double y;

  const Point({
    required this.x,
    required this.y,
  });

  factory Point.fromOffset(Offset offset, double width, double height) {
    return Point(
      x: double.parse((offset.dx / width).toStringAsFixed(4)),
      y: double.parse((offset.dy / height).toStringAsFixed(4)),
    );
  }

  factory Point.fromJson(
      Map<String, dynamic> json, double width, double height) {
    return Point(
      x: json['x'],
      y: json['y'],
    );
  }

  factory Point.fromList(List<dynamic> offSetList) {
    return Point(
      x: offSetList[0],
      y: offSetList[1],
    );
  }

  List<double> toList() {
    final List<double> offestList = [];
    offestList.addAll([x, y]);
    return offestList;
  }

  Map<String, dynamic> toJson(width, height) {
    final json = Map<String, dynamic>();
    json['x'] = x;
    json['y'] = y;
    return json;
  }

  double get distance => sqrt(x * x + y * y);

  // Point operator -(Point other) => Point(x: x - other.x, y: y - other.y);

  Offset toOffset(double width, double height) => Offset(x * width, y * height);
}

/// Line 线类
class Line {
  List<Point> points = [];
  PaintState state;
  PaintType paintType;
  double strokeWidth;
  Color color;
  String userId;

  Line({
    this.color = Colors.black,
    this.strokeWidth = 1,
    this.state = PaintState.doing,
    this.paintType = PaintType.curvedLine,
    required this.userId,
  });

  void paint(Canvas canvas, Paint paint, double width, double height) {
    paint
      ..color = color
      ..isAntiAlias = true
      ..style = PaintingStyle.stroke
      ..strokeWidth = strokeWidth
      ..strokeCap = StrokeCap.round;
    List<Point> pointList = [];
    if (points.length < 10) {
      pointList = points;
    } else {
      for (int i = 0; i < points.length; i++) {
        if (i % 3 == 0) {
          pointList.add(points[i]);
        }
      }
    }

    canvas.drawPoints(
      PointMode.polygon,
      pointList.map<Offset>((e) => e.toOffset(width, height)).toList(),
      paint,
    );
  }
}