boolean isPointOnCircle(Graphics oval, Point p) {
	Rectangle r = oval.getClipBounds();
	double cap = (r.width)/2;
	double centerX = (r.x) + cap;
	double centerY = (r.y) + cap;
	double distance = Math.sqrt(Math.pow((centerX - p.x),2) + Math.pow((centerY - p.y),2));
	if(distance <= cap)
		return true;
	else
		return false;
}

import java.awt.*;
import java.awt.event.*;
import java.applet.*;
import java.util.*;

public class SoruAlt extends Applet
	implements  KeyListener, MouseListener, MouseMotionListener {

	Point mouseCoord; // fareyi surekli takip eder
	Color brush = Color.black; // firca rengi
	ArrayList<Graphics> list = new ArrayList<Graphics>(); // grafik listesi
	Label label = new Label("Toplam: 0"); // sekil sayisini gosteren etiket

	public void init() {
		/* olaylari dinle */
		addKeyListener(this);
		requestFocus();
		addMouseListener(this);
		addMouseMotionListener(this);

		/* etiketi yerlestir */
		this.setLayout(null);
		add(label);

		/* etiket klavye dinlemeli yoksa klavye hic dinlenmez */
		label.addKeyListener(this);
		label.requestFocus();
	}

	public void paint(Graphics g) {

		/* Listedeki daireleri ciz */
		Rectangle r;
		int numOvals = list.size();
		for(int i=0; i<numOvals; i++) {
			g = list.get(i); // listeden nesneyi cek

			/* grafigi ciz */
			r = g.getClipBounds();
			g.fillOval(r.x, r.y, r.width, r.height);
		}

		/* Toplam daire sayisini goster */
		label.setBounds(getWidth()-80,0, 80, 20);
		label.setText("Toplam: "+list.size());
	}

	/* farenin altında en ondeki direnin ve fircanin rengini degistirir  */
	public void ChangeBrush(Color c) {
		Graphics g;
		Rectangle r;
		int i, numOvals = list.size(); // eleman sayisini bul
		this.brush = c; // firca rengini degistir
		
		/* fare altinda en ondeki daireyi bulur */
		for(i=numOvals-1; i>=0; i--) {
			g = list.get(i); // listeden nesneyi cek
			r = g.getClipBounds();
			if(isPointOnCircle(g, new Point(mouseCoord.x, mouseCoord.y))) {
				g.setColor(brush); // dairenin rengini degistir

				/* sadece gecerli daireyi yeniden ciz */
				repaint(r.x, r.y, r.width, r.height);
				break;
			}
		}
	}

	private boolean isPointOnCircle(Graphics oval, Point p) {
		Rectangle r = oval.getClipBounds();
		double cap = (r.width)/2;
		double centerX = (r.x) + cap;
		double centerY = (r.y) + cap;
		double distance = Math.sqrt(Math.pow((centerX - p.x),2) + Math.pow((centerY - p.y),2));
		if(distance <= cap)
			return true;
		else
			return false;
	}

	public void keyPressed(KeyEvent ke) {
		int keynum = ke.getKeyCode();
		if(keynum == KeyEvent.VK_DELETE || keynum == KeyEvent.VK_D) {
			Graphics g;
			Rectangle r;
			int i, numOvals = list.size(); // eleman sayisini bul

			/* fare altinda en ondeki daireyi bulur */
			for(i=numOvals-1; i>=0; i--) {
				g = list.get(i); // listeden nesneyi cek
				r = g.getClipBounds();

				if(isPointOnCircle(g, new Point(mouseCoord.x, mouseCoord.y))) {
					list.remove(g); // sekli listeden sil

					/* silinen yeri tazele */
					repaint(r.x, r.y, r.width, r.height);
					break;
				}
			}
		}
		else if(keynum == KeyEvent.VK_F1)
			ChangeBrush(Color.red);
		else if(keynum == KeyEvent.VK_F2)
			ChangeBrush(Color.blue);
		else if(keynum == KeyEvent.VK_F3)
			ChangeBrush(Color.green);
	}
	public void keyReleased(KeyEvent ke) {
	}
	public void keyTyped(KeyEvent ke) {
	}

	public void mouseClicked(MouseEvent me) {
	}
	public void mousePressed(MouseEvent me) {
		Graphics g = getGraphics(); // yeni grafik nesnesi
		g.setColor(brush); // nesnenin rengini ayarla
		
		/* 20px yaricapli dairenin merkez koordinatlari */
		int x = me.getX()-20;
		int y = me.getY()-20; 
		
		g.setClip(x,y,40,40); // sekli ayarla
		list.add(g); // sekli listeye ekle
		repaint(x,y,40,40); // olay bolgesini tazele
	}
	public void mouseReleased(MouseEvent me) {
	}
	public void mouseExited(MouseEvent me) {
	}
	public void mouseEntered(MouseEvent me) {
	}

	public void mouseDragged(MouseEvent me) {
	}
	public void mouseMoved(MouseEvent me) {
		/* fare koordinatlarini izle */
		mouseCoord = me.getPoint();
	}
}