import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import java.util.List;
import java.util.*;
import javax.swing.event.*;
 
public class DrawingRectangles
{
    public static void main(String[] args)
    {
        Frame f = new Frame();
        f.addWindowListener(new WindowAdapter()
        {
            public void windowClosing(WindowEvent e)
            {
                System.exit(0);
            }
        });
        f.add(new RectangleDrawingPanel());
        f.setSize(400,400);
        f.setLocation(200,200);
        f.setVisible(true);
    }
}
 
class RectangleDrawingPanel extends Panel
{
    List shapes;
    Rectangle newRect;
    int minX, minY, maxX, maxY;
    Point offscreen;
    boolean showClip;
    RectangleMaker maker;
 
    public RectangleDrawingPanel()
    {
        shapes = new ArrayList();
        newRect = new Rectangle();
        offscreen = new Point(-1, -1);
        resetClipBounds(offscreen);
        showClip = false;
        maker = new RectangleMaker(this);
        addMouseListener(maker);
        addMouseMotionListener(maker);
    }
 
    public void paint(Graphics g)
    {
        super.paint(g);
        Graphics2D g2 = (Graphics2D)g;
        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                            RenderingHints.VALUE_ANTIALIAS_ON);
        for(Shape s : shapes)
            g2.draw(s);
        if(maker.dragging)
            g2.draw(newRect);
        if(showClip)
        {
            g2.setPaint(Color.red);
            g2.fillOval(minX - 2, minY - 2, 4, 4);
            g2.fillOval(minX - 2, maxY - 2, 4, 4);
            g2.fillOval(maxX - 2, minY - 2, 4, 4);
            g2.fillOval(maxX - 2, maxY - 2, 4, 4);
        }
    }
 
    public void addShape()
    {
        Rectangle r = (Rectangle)newRect.clone();
        shapes.add(r);
        resetClipBounds(offscreen);
        repaint();
    }
 
    public void clear()
    {
        shapes.clear();
        newRect.setFrame(0, 0, 0, 0);
        resetClipBounds(offscreen);
        repaint();
    }
 
    public void setRectangle(Point p1, Point p2)
    {
        newRect.setFrameFromDiagonal(p1, p2);
        int x = p2.x >= p1.x ? p1.x - 1 : p2.x - 1;
        int y = p2.y >= p1.y ? p1.y - 1 : p2.y - 1;
        int w = Math.abs(p1.x - p2.x) + 2;
        int h = Math.abs(p1.y - p2.y) + 2;
        updateClipBounds(x, y, w, h);
        repaint(minX, minY, maxX, maxY);
    }
 
    private void updateClipBounds(int x, int y, int w, int h)
    {
        if(x < minX)     minX = x;
        if(y < minY)     minY = y;
        if(x + w > maxX) maxX = x + w;
        if(y + h > maxY) maxY = y + h;
    }
 
    protected void resetClipBounds(Point p)
    {
        minX = maxX = p.x;
        minY = maxY = p.y;
    }
}
 
class RectangleMaker extends MouseInputAdapter
{
    RectangleDrawingPanel drawPanel;
    Point start;
    boolean dragging;
 
    public RectangleMaker(RectangleDrawingPanel rdp)
    {
        drawPanel = rdp;
        dragging = false;
    }
 
    public void mousePressed(MouseEvent e)
    {
        // double click clears the drawing surface
        if(e.getClickCount() >= 2)
        {
            dragging = false;
            drawPanel.clear();
            return;
        }
        Point p = e.getPoint();
        start = p;
        drawPanel.resetClipBounds(p);    // start new clip
        dragging = true;
    }
 
    public void mouseReleased(MouseEvent e)
    {
        dragging = false;
        if(start.distance(e.getPoint()) > 5)
            drawPanel.addShape();
    }
 
    public void mouseDragged(MouseEvent e)
    {
        if(dragging)
            drawPanel.setRectangle(start, e.getPoint());
    }
}