Graphs_dart/flutter/lib/curve_painter.dart

import 'package:arrow_path/arrow_path.dart';
import 'package:graphs/src/graph.dart';
import 'package:flutter/material.dart';
import 'dart:math';

class CurvePainter extends CustomPainter {
  CurvePainter({
    Key? key,
    required this.gr,
  });

  Graphs gr;
  final double rad = 7;
  final double width = 4;
  final Color col = Colors.black;
  final double aboveHeight = 5;
  double circleRad = 100;
  final TextStyle textStyle = const TextStyle(
    color: Colors.black,
    fontSize: 21,
  );

  void drawLine(Canvas canvas, Offset p1, Offset p2) {
    Paint p = Paint();
    p.color = col;
    p.strokeWidth = width - 2;
    canvas.drawLine(p1, p2, p);
  }

  void drawDot(Canvas canvas, Offset p1) {
    var p = Paint();
    p.color = col;
    p.strokeWidth = width;
    canvas.drawCircle(p1, rad, p);
  }

  void drawSelfConnect(Canvas canvas, Offset p1) {
    var p = Paint();
    p.color = col;
    p.strokeWidth = width - 2;
    p.style = PaintingStyle.stroke;
    canvas.drawCircle(Offset(p1.dx + rad + 20, p1.dy), rad + 20, p);
  }

  TextSpan _getTextSpan(String s) => TextSpan(text: s, style: textStyle);
  TextPainter _getTextPainter(String s) => TextPainter(
      text: _getTextSpan(s),
      textDirection: TextDirection.ltr,
      textAlign: TextAlign.center);

  void drawAboveText(Canvas canvas, Offset size, String s) {
    var textPainter = _getTextPainter(s);
    textPainter.layout();
    textPainter.paint(
        canvas,
        Offset((size.dx - textPainter.width),
            (size.dy - textPainter.height) - aboveHeight));
  }

  Graphs getGraph() {
    List<Dot> d = <Dot>[];
    d.add(Dot.fromTwoLists("1", [2, 3], [1, 1]));
    d.add(Dot.fromTwoLists("2", [1, 3], [1, 1]));
    d.add(Dot.fromTwoLists("3", [1, 2], [1, 1]));
    d.add(Dot.fromTwoLists("Name1", [], []));
    d.add(Dot.fromTwoLists("Name2", [], []));
    return Graphs.fromList("1", d, false, false);
  }

  Map<int, Offset> getDotPos(int dotsAm, Size size) {
    Map<int, Offset> off = <int, Offset>{};
    var width = size.width / 2;
    var height = size.height / 2;
    for (int i = 0; i < dotsAm; i++) {
      double x = cos(2 * pi * i / dotsAm) * circleRad + width;
      double y = sin(2 * pi * i / dotsAm) * circleRad + height;
      off[i + 1] = Offset(x, y);
    }
    //print(off);
    return off;
  }

  void drawArrow(Canvas canvas, Offset from, Offset to,
      [bool doubleSided = false]) {
    Path path;

    // The arrows usually looks better with rounded caps.
    Paint paint = Paint()
      ..color = Colors.black
      ..style = PaintingStyle.stroke
      ..strokeCap = StrokeCap.round
      ..strokeJoin = StrokeJoin.round
      ..strokeWidth = width - 1;

    /// Draw a single arrow.
  path = Path();
    path.moveTo(from.dx, from.dy);
    path.relativeCubicTo(0, 0, 0, 0, to.dx - from.dx, to.dy - from.dy);
    path =
        ArrowPath.make(path: path, isDoubleSided: doubleSided, tipLength: 13);
    canvas.drawPath(path, paint);
  }

  void drawConnections(Canvas canvas, List<Dot> dots, Map<int, Offset> off) {
    for (var i in dots) {
      var list = i.getL();
      var beg = off[i.num];
      for (var d in list.keys) {
        if (d == i.num) {
          drawSelfConnect(canvas, off[d]!);
        } else {
          drawArrow(canvas, beg!, off[d]!, !gr.getDoubleSidedBool());
        }
      }
    }
  }

  @override
  void paint(Canvas canvas, Size size) {
    if (size.width > size.height) {
      circleRad = size.height / 3;
    } else {
      circleRad = size.width / 3;
    }
    //var paint = Paint();
    //drawLine(canvas, Offset(0, size.height / 2),
    //Offset(size.width, size.height / 2));

    //gr = getGraph();
    var off = getDotPos(gr.getDotAmount(), size);
    for (int i = 0; i < off.length; i++) {
      drawDot(canvas, off[i + 1]!);
      drawAboveText(
          canvas, off[i + 1]!, "${gr.getDots()[i].getName()}:[${i + 1}]");
    }
    drawConnections(canvas, gr.getDots(), off);
    //drawArrow(canvas, Offset(size.width / 2, size.height / 2),
    //   Offset(size.width / 2 + 50, size.height / 2 + 200));
  }

  @override
  bool shouldRepaint(CustomPainter oldDelegate) {
    return true;
  }

  /*void _drawTextAt(String txt, Offset position, Canvas canvas) {
    final textPainter = getTextPainter(txt);
    textPainter.layout(minWidth: 0, maxWidth: 0);
    Offset drawPosition =
        Offset(position.dx, position.dy - (textPainter.height / 2));
    textPainter.paint(canvas, drawPosition);
  }*/
}