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 DrawEclipse
{
    public partial class Form1 : Form
    {
        //Declare the event handler and deligate to handle the events
        private delegate void EclipseClickedEventHandler(object sender);
        private event EclipseClickedEventHandler Eclipse_Clicked;

        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            //Initialise the Click Event for eclipse we are drawing
            this.Eclipse_Clicked += new EclipseClickedEventHandler(Eclipse1_Cliked);
        }

        private void Form1_Paint(object sender, PaintEventArgs e)
        {
            //Draw eclipse in Form paint method
            Graphics g = e.Graphics;
            g.DrawEllipse(Pens.Blue, 30, 30, 50, 50);
        }

        private void Form1_MouseDown(object sender, MouseEventArgs e)
        {
            //To give clicking effect we need to draw a similar eclipse when you
            // press the mouse, also check the bounds where mouse is being clicked
            if (e.X >= 30 && e.Y <= 80)
            {
                Graphics g = this.CreateGraphics();
                //Clear the exisiting eclipse, following code draw a eclipse with form's 
                // background color so eclipse will be cleard
                Pen p = new Pen(this.BackColor);
                g.DrawEllipse(p, 30, 30, 50, 50);
                // draw new eclipse
                g.DrawEllipse(Pens.Blue, 31, 31, 52, 52);
                Application.DoEvents();
                //raise the clicking event
                Eclipse_Clicked(sender);
            }
        }

        private void Form1_MouseUp(object sender, MouseEventArgs e)
        {
            //When you release the mouse button you need to draw eclipse at old position
            // so that will have the clicking effect.
            if (e.X >= 30 && e.Y <= 80)
            {
                Graphics g = this.CreateGraphics();
                Pen p = new Pen(this.BackColor);
                g.DrawEllipse(p, 31, 31, 52, 52);
                g.DrawEllipse(Pens.Blue, 30, 30, 50, 50);
                Application.DoEvents();
                Eclipse_Clicked(sender);
            }
        }

        //This will be called when you click the eclipse
        private void Eclipse1_Cliked(object sender)
        {
            Graphics g = this.CreateGraphics();
            g.DrawEllipse(Pens.Yellow, 100, 100, 50, 50);
            //This event will be fired when you click on eclipse
            //Here you can draw 2d objects
        }
    }
}