using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;

namespace Sketch_dotNet_bitmap
{
	/// <summary>
	/// Summary description for Form1.
	/// </summary>
	public class Form1 : System.Windows.Forms.Form
	{

		bool btn_Down;
		Point ptLast;
		Bitmap bmShadow;
		Graphics gBitmap;      // graphics object associated with the shadow bitmap
		int cWidth, cHeight;   // width and height of client area

		/// <summary>
		/// Required designer variable.
		/// </summary>
		private System.ComponentModel.Container components = null;

		public Form1()
		{
			//
			// Required for Windows Form Designer support
			//
			InitializeComponent();

			//
			// TODO: Add any constructor code after InitializeComponent call
			//

			this.BackColor = SystemColors.Window;
			this.ForeColor = SystemColors.WindowText;
			bmShadow = new Bitmap(this.Width, this.Height);
			gBitmap = Graphics.FromImage(bmShadow);
			gBitmap.Clear(this.BackColor);
		}

		/// <summary>
		/// Clean up any resources being used.
		/// </summary>
		protected override void Dispose( bool disposing )
		{
			if( disposing )
			{
				if (components != null) 
				{
					components.Dispose();
				}
			}
			base.Dispose( disposing );
		}

		#region Windows Form Designer generated code
		/// <summary>
		/// Required method for Designer support - do not modify
		/// the contents of this method with the code editor.
		/// </summary>
		private void InitializeComponent()
		{
			// 
			// Form1
			// 
			this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
			this.ClientSize = new System.Drawing.Size(344, 273);
			this.Name = "Form1";
			this.Text = "Permanent sketch with shadow bitmap";
			this.MouseDown += new System.Windows.Forms.MouseEventHandler(this.Form1_MouseDown);
			this.MouseUp += new System.Windows.Forms.MouseEventHandler(this.Form1_MouseUp);
			this.Paint += new System.Windows.Forms.PaintEventHandler(this.Form1_Paint);
			this.MouseMove += new System.Windows.Forms.MouseEventHandler(this.Form1_MouseMove);

		}
		#endregion

		/// <summary>
		/// The main entry point for the application.
		/// </summary>
		[STAThread]
		static void Main() 
		{
			Application.Run(new Form1());
		}

		private void Form1_MouseDown(object sender, System.Windows.Forms.MouseEventArgs e)
		{
			if (e.Button == MouseButtons.Left)
			{
				ptLast = new Point(e.X, e.Y);
				btn_Down = true;
			}
		}

		private void Form1_MouseMove(object sender, System.Windows.Forms.MouseEventArgs e)
		{
			if (btn_Down)
			{
				Point ptNew = new Point(e.X, e.Y);
				Pen p = new Pen(this.ForeColor);
				Graphics gScreen = this.CreateGraphics();
				gScreen.DrawLine(p, ptLast, ptNew);       // draw new line segment on screen
				gScreen.Dispose();
				gBitmap.DrawLine(p, ptLast, ptNew);       // draw new line segment on shadow bitmap
				ptLast = ptNew;
			}
		}

		private void Form1_MouseUp(object sender, System.Windows.Forms.MouseEventArgs e)
		{
			btn_Down = false;
		}

		private void Form1_Paint(object sender, System.Windows.Forms.PaintEventArgs e)
		{
			Graphics gScreen = e.Graphics;
			gScreen.DrawImage(bmShadow, 0, 0, bmShadow.Width, bmShadow.Height);
			                                             // draw shadow bitmap on screen
		}
	}
}