Forel.cs

using System;
using System.Collections.Generic;
using System.Drawing;
using System.Linq;

namespace Clusterization_algorithms
{
    public class Forel
    {
        public int clusterNum = 0;
        public List<Point> ListOfClastersCenter = new List<Point>();

        /* Dictionary contain all pairs (point, number_of_cluster),
         * if (cluster = 0) => point/node not belong to cluster*/
        private Dictionary<Point, int> _points = new Dictionary<Point, int>();
        private int _radius; // nodes search radius
        private GraphicsController _graphics;
        
        public int Radius { get => _radius; set => _radius = value; }

        public Forel()
        {
        }

        public Forel(GraphicsController graphics)
        {
            _graphics = graphics;
        }

        public void SetPoints(Dictionary<Point, int> pointDictionary)
        {
            _points.Clear();
            ListOfClastersCenter.Clear();

            foreach (KeyValuePair<Point, int> point in pointDictionary)
            {
                _points.Add(point.Key, point.Value);
            }
        }

        public Dictionary<Point, int> GetPoints()
        {
            return _points;
        }

        /// <summary>
        /// Add selected point to cluster
        /// </summary>
        private void AddToCluster(Point key)
        {
            _points.Remove(key);
            _points.Add(key, clusterNum);
        }

        /// <summary>
        /// Add points to the cluster
        /// </summary>
        private void AddPointsToCluster(List<Point> pointsList)
        {
            foreach (Point point in pointsList)
            {
                AddToCluster(point);
            }
        }

        /// <summary>
        /// Get cluster from the cluster center coordinates
        /// </summary>
        private List<Point> GetCluster(Point center)
        {
            List<Point> cluster = new List<Point> { };

            for (int i = 0; i < _points.Count; i++)
            {

                if (_points.ElementAt(i).Value == 0)
                {
                    double distance = Calculator.CalcDistance(center, _points.ElementAt(i).Key);

                    if (distance <= _radius)
                    {
                        cluster.Add(_points.ElementAt(i).Key);
                    }
                }
            }

            return cluster;
        }

        /// <summary>
        /// Calculate new centroid (mass center)
        /// </summary>
        private Point FindNewCenter(Point center)
        {
            List<Point> cluster = GetCluster(center);

            if (cluster.Count == 0){ // if cluster no have elements, new_center = center
                
                _graphics.DrawCircle(center, _radius, Color.Black);
                ListOfClastersCenter.Add(center);
                return center;
            }

            Point newCenter = Calculator.FindCentroid(cluster);
            _graphics.DrawPoint(newCenter, Brushes.Pink, 6);
            _graphics.DrawCircle(newCenter, _radius, Color.LightGray);

            if (center == newCenter){
                _graphics.DrawCircle(center, _radius, Color.Black);
                _graphics.DrawPoint(newCenter, Brushes.Red, 6);
                ListOfClastersCenter.Add(center);
            }
                
            return newCenter;
        }

        /// <summary>
        /// Start calculating clusters
        /// </summary>
        private Point StartClusterisation(Point center)
        {
            Point newCenter = FindNewCenter(center);

            if (newCenter != center)
                StartClusterisation(newCenter);
            else
                AddPointsToCluster(GetCluster(newCenter));

            return newCenter;
        }


        /// <summary>
        /// START FOREL CLUSTERISATION
        /// </summary>
        public void StartForel()
        {
            clusterNum = 0;

            for (int i = 0; i < _points.Count; i++)
            {

                if (_points.ElementAt(i).Value == 0)
                {
                    clusterNum++;
                    StartClusterisation(_points.ElementAt(i).Key);
                }
            }
        }

        /// <summary>
        /// Print formatted to TextBox
        /// </summary>
        private void PrintList(List<Point> list)
        {
            Console.WriteLine("Print point list:");
            int counter = 1;

            foreach (Point p in list)
            {
                Console.Write(p + " ");
                if (counter % 10 == 0)
                    Console.WriteLine();
                counter++;
            }
        }
    }
}