using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace koh
{
    public partial class Emulator : Form
    {
        static Pen pen1;
        static Graphics g;
        static Pen pen2;
        public Emulator()
        {
            InitializeComponent();
        }
        private void Draw(object sender, EventArgs e)
        {
            g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;
            //Объявляем объект "g" класса Graphics
            g = CreateGraphics();
            g.Clear(Color.Black);//Зарисовка экрана черным фоном
            //Определим коорднаты исходного треугольника
            var point1 = new PointF(200, 200);
            var point2 = new PointF(500, 200);
            var point3 = new PointF(350, 400);
            for (int d = 15; d <= 175; ++d)
            {

             Random rnd = new Random();
             //Выбираем цвета зарисовки
             for (int m = 1; m < 5; m++) {
                Pen pen1a = new Pen(Color.FromArgb(rnd.Next(255), rnd.Next(255), rnd.Next(255), rnd.Next(255)), m);
                float x1, x2, x3, y1, y2, y3;
                x1 = 450; x1 -= d;
                y1 = 400; y1 -= d;
                x2 = 50; x2 += d;
                y2 = 400; y2 -= d;
                x3 = 250;
                y3 = 50; y3 += d;
                var point1a = new PointF(x1, y1);
                var point2a = new PointF(x2, y2);
                var point3a = new PointF(x3, y3);
                g.DrawLine(pen1a, point1a, point2a);
                g.DrawLine(pen1a, point2a, point3a);
                g.DrawLine(pen1a, point3a, point1a);

              for (int n = 0; n < 5;n++ )
              {
                Fractal(point1a, point2a, point3a, n);
                Fractal(point2a, point3a, point1a, n);
                Fractal(point3a, point1a, point2a, n);
              }
            }}
}
        //рекурсивная функция рисования кривой Коха
        static int Fractal(PointF p1, PointF p2, PointF p3, int iter)
        {
            //n -количество итераций
            if (iter > 0)  //условие выхода из рекурсии
            {
                g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;
                Random rnd = new Random();
                Pen pen2a = new Pen(Color.FromArgb(rnd.Next(255), rnd.Next(255), rnd.Next(255), rnd.Next(255)), 1);
                //средняя треть отрезка
                var p4 = new PointF((p2.X + 2 * p1.X) / 3, (p2.Y + 2 * p1.Y) / 3) ;
                var p5 = new PointF((2 * p2.X + p1.X) / 3, (p1.Y + 2 * p2.Y) / 3) ;
                //координаты вершины угла
                var ps = new PointF((p2.X + p1.X) / 2, (p2.Y + p1.Y) / 2) ;
                var pn = new PointF((4 * ps.X - p3.X) / 3, (4 * ps.Y - p3.Y) / 3) ;
                //рисуем его
                g.DrawLine(pen2a, p4, pn);
                g.DrawLine(pen2a, p5, pn);
                g.DrawLine(pen2a, p4, p5);
                //рекурсивно вызываем функцию нужное число раз
                Fractal(p4, pn, p5, iter - 1);
                Fractal(pn, p5, p4, iter - 1);
                Fractal(p1, p4, new PointF((2 * p1.X + p3.X) / 3, (2 * p1.Y + p3.Y) / 3), iter - 1);
                Fractal(p5, p2, new PointF((2 * p2.X + p3.X) / 3, (2 * p2.Y + p3.Y) / 3), iter - 1);
            }
            return iter;
        }

    }
}