using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
 
namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            DoubleBuffered = true;
        }
 
        struct RectangleParametres
        {
            public int X;
            public int Y;
            public int Width;
            public int Height;
        }
 
        RectangleParametres[] RectParams = new RectangleParametres[0];
        int X = 0;
        int Y = 0;
 
        private void Form1_MouseDown(object sender, MouseEventArgs e)
        {
            X = e.X;
            Y = e.Y;
            Array.Resize(ref RectParams, RectParams.Length + 1);
        }
 
        private void Form1_MouseMove(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)
            {
                Bitmap bm = new Bitmap(Width, Height);
                Graphics g = Graphics.FromImage(bm);
                if (X < e.X)
                {
                    RectParams[RectParams.Length - 1].Width = e.X - X;
                    RectParams[RectParams.Length - 1].X = X;
                }
                else
                {
                    RectParams[RectParams.Length - 1].Width = X - e.X;
                    RectParams[RectParams.Length - 1].X = X - RectParams[RectParams.Length - 1].Width;
                }
                if (Y < e.Y)
                {
                    RectParams[RectParams.Length - 1].Height = e.Y - Y;
                    RectParams[RectParams.Length - 1].Y = Y;
                }
                else
                {
                    RectParams[RectParams.Length - 1].Height = Y - e.Y;
                    RectParams[RectParams.Length - 1].Y = Y - RectParams[RectParams.Length - 1].Height;
                }
                for (int i = 0; i < RectParams.Length; i++)
                    g.DrawRectangle(new Pen(Color.Black, 4), RectParams[i].X, RectParams[i].Y, RectParams[i].Width, RectParams[i].Height);
                BackgroundImage = bm;
            }
        }
    }
}