/*
 * A C# program that responds to mouse events with drawing.
 *
 * Ben Bederson, February 20, 2002
 */

using System;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Windows.Forms;

public class Draw : System.Windows.Forms.Form {
    static public void Main() {
	Application.Run(new Draw());
    }

    public Draw() {
	Size = new Size(400, 400);
	StartPosition = FormStartPosition.CenterScreen;
        DrawingCanvas control = new DrawingCanvas();
	control.Location = new Point(0, 0);
	control.Size = new Size(400, 400);

	Controls.Add(control);
    }
}

class DrawingCanvas : Control {
    Pen blackPen = new Pen(Color.Black);
    GraphicsPath path = null;
    int prevx, prevy;

    public DrawingCanvas() {
	BackColor = Color.White;
	MouseDown += new MouseEventHandler(mouseDownHandler);
        MouseMove += new MouseEventHandler(mouseMoveHandler);
    }

    public void mouseDownHandler(object sender, MouseEventArgs e) {
	prevx = e.X;
	prevy = e.Y;
	path = new GraphicsPath();
    }

    public void mouseMoveHandler(object sender, MouseEventArgs e) {
	if (e.Button != MouseButtons.None) {
	    path.AddLine(prevx, prevy, e.X, e.Y);
	    prevx = e.X;
	    prevy = e.Y;
	    Invalidate();
	}
    }

    protected override void OnPaint(PaintEventArgs e) {
        Graphics g = e.Graphics;
	if (path != null) {
	    g.DrawPath(blackPen, path);
	}
    }
}