fis_lib_business_components/lib/components/white_board/white_board_painter.dart

import 'package:fis_lib_business_components/components/white_board/structure.dart';
import 'package:flutter/material.dart';

/// 白板 Canvas
class WhiteBoardPainter extends CustomPainter {
  final WhiteBoardPen pen;
  final double width;
  final double height;

  WhiteBoardPainter({required this.pen, this.width = 0.0, this.height = 0.0})
      : super(repaint: pen);

  final Paint _paint = Paint();

  @override
  void paint(Canvas canvas, Size size) {
    /// 遍历每一根线，绘制
    for (var line in pen.lines) {
      line.paint(
        canvas,
        _paint,
        width,
        height,
      );
    }
  }

  @override
  bool shouldRepaint(covariant WhiteBoardPainter oldDelegate) {
    bool needRepaint = oldDelegate.pen != pen;
    return needRepaint;
  }
}

/// 白板画笔
class WhiteBoardPen extends ChangeNotifier {
  final List<Line> _lines = [];

  List<Line> get lines => _lines;

  Line get activeLine => _lines.singleWhere(
        (element) => element.state == PaintState.doing,
        orElse: () => Line(userId: ''),
      );

  void pushLine(Line line) {
    _lines.add(line);
  }

  void pushPoint(Point point) {
    activeLine.points.add(point);
    if (activeLine.paintType == PaintType.straightLine) {
      activeLine.points = [activeLine.points.first, activeLine.points.last];
    }
    notifyListeners();
  }

  void doneLine() {
    activeLine.state = PaintState.done;
    notifyListeners();
  }

  void clear() {
    for (var line in _lines) {
      line.points.clear();
    }
    _lines.clear();
    notifyListeners();
  }

  void clearCurrectUserLines(String userId) {
    for (int i = 0; i < _lines.length; i++) {
      if (_lines[i].userId == userId) {
        _lines[i].points.clear();
      }
    }
    _lines.removeWhere((element) => element.userId == userId);

    notifyListeners();
  }

  void removeEmpty() {
    _lines.removeWhere((element) => element.points.isEmpty);
  }
}