Help needed in creating a simple paint application

Question

I want to create a simple paint application using swings in java, i am able to draw different shapes using mouse but the problem is when i select some other shape it simply replaces the already drawn object with the new one but i want the already drawn object also, like appending, what should be done for this, any logic missing here or i should use some other approach?
Please help me
package test;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class bmp extends JFrame implements MouseListener, MouseMotionListener,
          ActionListener {
     int w, h;
     int xstart, ystart, xend, yend;
     JButton elipse = new JButton("--Elipse--");
     JButton rect = new JButton  ("Rectangle");
     JPanel mainframe = new JPanel();
     JPanel buttons = new JPanel();
     String selected="no";
     public void init() {
          //super("Bitmap Functions");
          // display.setLayout(new FlowLayout());
          buttons.setLayout(new BoxLayout(buttons,BoxLayout.Y_AXIS));
          buttons.add(Box.createRigidArea(new Dimension(15,15)));
          buttons.add(elipse);
          buttons.add(Box.createRigidArea(new Dimension(0,15)));
          buttons.add(rect);
          Container contentpane = getContentPane();
          contentpane.add(buttons, BorderLayout.WEST);
          //getContentPane().add(display, BorderLayout.WEST);
          addMouseListener(this); // listens for own mouse and
          addMouseMotionListener(this); // mouse-motion events
          setSize(1152, 834);
          elipse.addActionListener(this);
          rect.addActionListener(this);
          setVisible(true);
     public void mousePressed(MouseEvent event) {
          xstart = event.getX();
          ystart = event.getY();
     public void mouseReleased(MouseEvent event) {
          xend = event.getX();
          yend = event.getY();
          repaint();
     public void mouseEntered(MouseEvent event) {
          //repaint();
     public void mouseExited(MouseEvent event) {
          //repaint();
     public void mouseDragged(MouseEvent event) {
          xend = event.getX();
          yend = event.getY();
          repaint();
     public void mouseMoved(MouseEvent event) {
          //repaint();
     public static void main(String args[]) {
          bmp application = new bmp();
          application.init();
          application.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
     public void mouseClicked(MouseEvent arg0) {
     public void actionPerformed(ActionEvent event) {
          if (event.getSource() == elipse) {
               selected = "elipse";
               repaint();
          else if(event.getSource() == rect)
               selected = "rectangle";
               repaint();
     public void paint(Graphics g) {
          System.out.println(selected);
          super.paint(g); // clear the frame surface
          bmp b=new bmp();
          if (selected.equals("elipse"))
               w = xend - xstart;
               h = yend - ystart;
               if (w < 0)
                    w = w * -1;
               if (h < 0)
                    h = h * -1;
               g.drawOval(xstart, ystart, w, h);
          if (selected.equals("rectangle"))
               w = xend - xstart;
          h = yend - ystart;
          if (w < 0)
               w = w * -1;
          if (h < 0)
               h = h * -1;
          g.drawRect(xstart, ystart, w, h);
}

Answer 1

bvivek wrote:
..With this code, when i draw an elipse or line the image doesnt start from the point where i click the mouse. It added the MouseListener to the wrong thing.
import java.awt.*;
import java.awt.event.*;
import java.awt.image.BufferedImage;
import javax.swing.*;
public class test_bmp extends JPanel implements MouseListener,MouseMotionListener,ActionListener
       static BufferedImage image;
       Color color;
       Point start=new Point();
       Point end =new Point();
       JButton elipse=new JButton("Elipse");
       JButton rectangle=new JButton("Rectangle");
       JButton line=new JButton("Line");
       String selected;
       public test_bmp()
               color = Color.black;
               setBorder(BorderFactory.createLineBorder(Color.black));
       public void paintComponent(Graphics g)
               //super.paintComponent(g);
               g.drawImage(image, 0, 0, this);
               Graphics2D g2 = (Graphics2D)g;
               g2.setPaint(Color.black);
       if(selected=="elipse")
               g2.drawOval(start.x, start.y, (end.x-start.x),(end.y-start.y));
               System.out.println("paintComponent() "+start.getX()+","+start.getY()+","+(end.getX()-start.getX())+","+(end.getY()-start.getY()));
               System.out.println("Start : "+start.x+","+start.y);
               System.out.println("End   : "+end.x+","+end.y);
       if(selected=="line")
               g2.drawLine(start.x,start.y,end.x,end.y);
       //Draw on Buffered image
       public void draw()
       Graphics2D g2 = image.createGraphics();
       g2.setPaint(color);
               System.out.println("draw");
       if(selected=="line")
               g2.drawLine(start.x, start.y, end.x, end.y);
       if(selected=="elipse")
               g2.drawOval(start.x, start.y, (end.x-start.x),(end.y-start.y));
               System.out.println("draw() "+start.getX()+","+start.getY()+","+(end.getX()-start.getX())+","+(end.getY()-start.getY()));
               System.out.println("Start : "+start.x+","+start.y);
               System.out.println("End   : "+end.x+","+end.y);
       repaint();
       g2.dispose();
       public JPanel addButtons()
               JPanel buttonpanel=new JPanel();
               buttonpanel.setBackground(color.lightGray);
               buttonpanel.setLayout(new BoxLayout(buttonpanel,BoxLayout.Y_AXIS));
               elipse.addActionListener(this);
               rectangle.addActionListener(this);
               line.addActionListener(this);
               buttonpanel.add(elipse);
               buttonpanel.add(Box.createRigidArea(new Dimension(15,15)));
               buttonpanel.add(rectangle);
               buttonpanel.add(Box.createRigidArea(new Dimension(15,15)));
               buttonpanel.add(line);
               return buttonpanel;
       public static void main(String args[])
                test_bmp application=new test_bmp();
                //Main window
                JFrame frame=new JFrame("Whiteboard");
                frame.setLayout(new BorderLayout());
                frame.add(application.addButtons(),BorderLayout.WEST);
                frame.add(application);
                application.addMouseListener(application);
                application.addMouseMotionListener(application);
                //size of the window
                frame.setSize(600,400);
                frame.setLocation(0,0);
                frame.setVisible(true);
                int w = frame.getWidth();
            int h = frame.getHeight();
            image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
            Graphics2D g2 = image.createGraphics();
            g2.setPaint(Color.white);
            g2.fillRect(0,0,w,h);
            g2.dispose();
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
       @Override
       public void mouseClicked(MouseEvent arg0) {
               // TODO Auto-generated method stub
       @Override
       public void mouseEntered(MouseEvent arg0) {
               // TODO Auto-generated method stub
       @Override
       public void mouseExited(MouseEvent arg0) {
               // TODO Auto-generated method stub
       @Override
       public void mousePressed(MouseEvent event)
               start = event.getPoint();
       @Override
       public void mouseReleased(MouseEvent event)
               end = event.getPoint();
               draw();
       @Override
       public void mouseDragged(MouseEvent e)
               end=e.getPoint();
               repaint();
       @Override
       public void mouseMoved(MouseEvent arg0) {
               // TODO Auto-generated method stub
       @Override
       public void actionPerformed(ActionEvent e)
               if(e.getSource()==elipse)
                       selected="elipse";
               if(e.getSource()==line)
                       selected="line";
               draw();
}