how to draw rectangle on applet based on mousedrageven

[kummu4help]

hi,
i want to draw rectangle based on mousedrag event. if user dragging the mouse, then the rectangle on the applet should increase or decrease basing on current mouse coordinates.
i have the following code.

in the following code i am using SelectionArea class which extends a canvas on which i am performing drawing operation. i am using image variable in this class for double buffering to reduce flickering and to save the applet's previous state(i.e drawing content of applet)

but the code is working fine if i draw first rectangle. if i start to draw second rectangle the previously drawn rectangle is disappearing. i want the previously drawn rectangle to be on the screen

can any one tell me how to solve this.

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

/* 
 * This displays a framed area.  When the user drags within
 * the area, this program displays a rectangle extending from
 * where the user first pressed the mouse button to the current
 * cursor location.
 */

public class RectangleDemo extends Applet {
    SelectionArea drawingPanel;
    Label label;

    public void init() {
        GridBagLayout gridBag = new GridBagLayout();
        GridBagConstraints c = new GridBagConstraints();

        setLayout(gridBag);

        drawingPanel = new SelectionArea(this);
        c.fill = GridBagConstraints.BOTH;
        c.weighty = 1.0;
        c.gridwidth = GridBagConstraints.REMAINDER; //end row
        gridBag.setConstraints(drawingPanel, c);
        add(drawingPanel);

        label = new Label("Drag within the framed area.");
        c.fill = GridBagConstraints.HORIZONTAL;
        c.weightx = 1.0;
        c.weighty = 0.0;
        gridBag.setConstraints(label, c);
        add(label);
        drawingPanel.setVisible(true);

        validate();
    }
    
    public void paint(Graphics g){
        drawingPanel.repaint();
    }
    
    public void update(Graphics g){
        paint(g);
    }
          

}

class SelectionArea extends Canvas implements ActionListener, MouseListener, MouseMotionListener{
    Rectangle currentRect;
    RectangleDemo controller;
    //for double buffering
    Image image;
    Graphics offscreen;
    public SelectionArea(RectangleDemo controller) {
        super();
        this.controller = controller;
        addMouseListener(this);
        addMouseMotionListener(this);        
    }

    public void actionPerformed(ActionEvent ae){
        repaintoffscreen();
    }
    
    public void repaintoffscreen(){
        image = createImage(this.getWidth(), this.getHeight());
        offscreen = image.getGraphics();
        Dimension d = getSize();
        if(currentRect != null){
            Rectangle box = getDrawableRect(currentRect, d);            
    
            //Draw the box outline.
            offscreen.drawRect(box.x, box.y, box.width - 1, box.height - 1);  
            //repaint();
        }
    }
    
    public void mouseEntered(MouseEvent me) {}
    public void mouseExited(MouseEvent me){ }
    public void mouseClicked(MouseEvent me){}
    public void mouseMoved(MouseEvent me){}
    
    public void mousePressed(MouseEvent me) {        
        currentRect = new Rectangle(me.getX(), me.getY(), 0, 0);
        repaintoffscreen();        
    }

    public void mouseDragged(MouseEvent me) {
        System.out.println("here in dragged()");
        currentRect.setSize(me.getX() - currentRect.x, me.getY() - currentRect.y);
        repaintoffscreen();    
        repaint();
    }

    public void mouseReleased(MouseEvent me) {
        currentRect.setSize(me.getX() - currentRect.x, me.getY() - currentRect.y);
        repaintoffscreen();  
        repaint();
    }

    public void update(Graphics g){
        paint(g);
    }
    
    public void paint(Graphics g) {
        g.drawImage(image, 0, 0, this);
    }

    Rectangle getDrawableRect(Rectangle originalRect, Dimension drawingArea) {
        int x = originalRect.x;
        int y = originalRect.y;
        int width = originalRect.width;
        int height = originalRect.height;

        //Make sure rectangle width and height are positive.
        if (width < 0) {
            width = 0 - width;
            x = x - width + 1;
            if (x < 0) {
                width += x;
                x = 0;
            }
        }
        if (height < 0) {
            height = 0 - height;
            y = y - height + 1;
            if (y < 0) {
                height += y;
                y = 0;
            }
        }

        //The rectangle shouldn't extend past the drawing area.
        if ((x + width) > drawingArea.width) {
            width = drawingArea.width - x;
        }
        if ((y + height) > drawingArea.height) {
            height = drawingArea.height - y;
        }

        return new Rectangle(x, y, width, height);
    }
}

also if i run this code on full screen mode then i am seeing that the rectangle is appering on screen only after i released the mouse. but i want the rectangle to be on the screen while dragging the mouse and it should change it's dimension according to the current mouse coordinates.
can any one help me pls.

[kummu4help]

hi
i modified my code as follows.
but now the rectangle is visible on the applet only after i release my mouse. but now i am able to draw multiple rectangles. the only problem is i can not see the rectangle while dragging the mouse.

import java.applet.*;
import java.awt.*;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseMotionListener;

public class testingDemo extends Applet {    
    private final int RECT_OP = 1;
    public int opStatus = 5;
    private int mousex = 0;
    private int mousey = 0;    
    public boolean dragging = false;
    private int Orx = 0;
    private int Ory = 0;
    private int OrWidth = 0;
    private int OrHeight = 0;
    private int drawX = 0;
    private int drawY = 0;    
    drawingPanel drawPanel;
    public Image image;    
    
    public void init() {
        setLayout(new BorderLayout());
        drawPanel = new drawingPanel();
        drawPanel.setVisible(true);
        this.setBackground(Color.white);
        add(drawPanel, BorderLayout.CENTER);
    }

    class drawingPanel extends Panel implements MouseListener, MouseMotionListener {

        drawingPanel() {
            addMouseListener(this);
            addMouseMotionListener(this);
        }

        public void rectOperation(MouseEvent e){
            mousex = e.getX();
            mousey = e.getY();
            setActualBoundry();
            if(image == null){
                image = this.createImage(this.getWidth(), this.getHeight());
            }
            Graphics offscreen = image.getGraphics();
            offscreen.setXORMode(Color.white);
            offscreen.drawRect(drawX, drawY, OrWidth, OrHeight);
            offscreen.drawRect(drawX, drawY, OrWidth, OrHeight);
            repaint();
        }

        public boolean mouseHasMoved(MouseEvent e) {
            return (mousex != e.getX() || mousey != e.getY());
        }

        public void setActualBoundry() {
            if (mousex < Orx || mousey < Ory) {
                if (mousex < Orx) {
                    OrWidth = Orx - mousex;
                    drawX = Orx - OrWidth;
                } else {
                    drawX = Orx;
                    OrWidth = mousex - Orx;
                }
                if (mousey < Ory) {
                    OrHeight = Ory - mousey;
                    drawY = Ory - OrHeight;
                } else {
                    drawY = Ory;
                    OrHeight = mousey - Ory;
                }
            } else {
                drawX = Orx;
                drawY = Ory;
                OrWidth = mousex - Orx;
                OrHeight = mousey - Ory;
            }
        }

        public void setGraphicalDefaults(MouseEvent e) {
            mousex = e.getX();
            mousey = e.getY();
            Orx = e.getX();
            Ory = e.getY();
            drawX = e.getX();
            drawY = e.getY();
            OrWidth =  0;
            OrHeight = 0;
        }

        public void mouseDragged(MouseEvent e) {            
            dragging = true;
            System.out.println("In mousedragged");
            opStatus = RECT_OP;
            rectOperation(e);            
        }

        public void mouseReleased(MouseEvent e) {            
            System.out.println("in mouseReleased()");
            dragging = false;
            opStatus = RECT_OP;
            mousex = e.getX();
            mousey = e.getY();
            setActualBoundry();
            releasedRect();            
        }

        public void mouseEntered(MouseEvent e) { }

        public void releasedRect() {
            System.out.println("in releasedRect()");            
            Graphics offscreen = image.getGraphics();
            offscreen.setXORMode(Color.white);
            offscreen.drawRect(drawX, drawY, OrWidth, OrHeight);
            offscreen.drawRect(drawX, drawY, OrWidth, OrHeight);
            offscreen.setPaintMode();
            offscreen.drawRect(drawX, drawY, OrWidth, OrHeight);
            offscreen.dispose();
            repaint();            
        }

        public void mouseClicked(MouseEvent e) {}

        public void mouseExited(MouseEvent e) {}

        public void mouseMoved(MouseEvent e) {}

        public void mousePressed(MouseEvent e) {
            setGraphicalDefaults(e);
            rectOperation(e);
        }

        public void paint(Graphics g) {
            g.drawImage(image, 0, 0, this);           
        }

        public void update(Graphics g) {
            paint(g);
        }
    }

    public void paint(Graphics g) {
        drawPanel.repaint();
    }

    public void update(Graphics g) {
        paint(g);
    }
}

can any one tell me what should i chagne in the above code so that the rectangle will be visible while dragging the mouse.
thanks for any help