using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

//This code is based on: http://support.microsoft.com/kb/314945
namespace RBRectangle
{
	public partial class Form1 : Form
	{
		bool bHaveMouse = false;
		Point ptOriginal = new Point();
		Point ptLast = new Point();
		List<Rectangle> rectList = new List<Rectangle>();

		public Form1()
		{
			InitializeComponent();
		}
		private void Form1_MouseDown(object sender, MouseEventArgs e)
		{
			if (e.Button == MouseButtons.Left)
			{
				// Make a note that we "have the mouse".
				bHaveMouse = true;

				// Store the "starting point" for this rubber-band rectangle.
				ptOriginal.X = e.X;
				ptOriginal.Y = e.Y;
				
				// Special value lets us know that no previous
				// rectangle needs to be erased.
				ptLast.X = -1;
				ptLast.Y = -1;
			}
			else if (e.Button == MouseButtons.Right)
			{
				Rectangle rectToRemove = new Rectangle();
				bool hitTest = false;
				foreach (Rectangle r in rectList)
				{
					if (r.Contains(e.X, e.Y))
					{
						if (MessageBox.Show("Delete this rectangle?", "Right click
								in rectangle", MessageBoxButtons.YesNo) == DialogResult.Yes)
						{
							rectToRemove = r;
							hitTest = true;
							break;
						}
					}
				}

				if (hitTest)
				{
					rectList.Remove(rectToRemove);
					Invalidate();
					Update();
				}
			}
		}

		private void Form1_MouseUp(object sender, MouseEventArgs e)
		{
			if (e.Button == MouseButtons.Right)
				return;

			// Set internal flag to know we no longer "have the mouse".
			bHaveMouse = false;

			// If we have drawn previously, draw again in that spot
			// to remove the lines.
			if( ptLast.X != -1 )
			{
				Rectangle r = MakeRectangle(ptOriginal, ptLast);
				MyDrawReversibleRectangle(r);
				MyDrawRealRectangle(r);
				rectList.Insert(0, r);
			}

			// Set flags to know that there is no "previous" line to reverse.
			ptLast.X = -1;
			ptLast.Y = -1;
			ptOriginal.X = -1;
			ptOriginal.Y = -1;
		}

		private void Form1_MouseMove(object sender, MouseEventArgs e)
		{
			Point ptCurrent = new Point( e.X, e.Y );

			// If we "have the mouse", then we draw our lines.
			if( bHaveMouse )
			{
				// If we have drawn previously, draw again in
				// that spot to remove the lines.
				if( ptLast.X != -1 )
				{
					MyDrawReversibleRectangle( MakeRectangle(ptOriginal, ptLast) );
				}

				// Update last point.
				ptLast = ptCurrent;
				
				// Draw new lines.
				MyDrawReversibleRectangle( MakeRectangle(ptOriginal, ptCurrent) );
			}
		}

		// Convert and normalize the points and draw the reversible frame.
		private void MyDrawReversibleRectangle(Rectangle r)
		{
			// Draw the reversible frame.
			ControlPaint.DrawReversibleFrame( RectangleToScreen(r),
			Color.Red, FrameStyle.Thick );
		}

		private void MyDrawRealRectangle( Rectangle r )
		{
			// Draw the rectangle.
			Graphics g = CreateGraphics();
			Pen p = new Pen(Color.Red, 3);
			g.DrawRectangle(p, r);
			p.Dispose();
			g.Dispose();
		}

		private Rectangle MakeRectangle( Point p1, Point p2 )
		{
			Rectangle rc = new Rectangle();
			
			// Normalize the rectangle.
			if( p1.X < p2.X )
			{
				rc.X = p1.X;
				rc.Width = p2.X - p1.X;
			}
			else
			{
				rc.X = p2.X;
				rc.Width = p1.X - p2.X;
			}

			if( p1.Y < p2.Y )
			{
				rc.Y = p1.Y;
				rc.Height = p2.Y - p1.Y;
			}
			else
			{
				rc.Y = p2.Y;
				rc.Height = p1.Y - p2.Y;
			}
			return rc;
		}

		private void Form1_Paint(object sender, PaintEventArgs e)
		{
			Graphics g = e.Graphics;
			foreach(Rectangle r in rectList)
			{
				MyDrawRealRectangle(r);
			}
		}
	}
}