Painting new objects without repainting old objects

Question

Halle you
I am a no- vice in this branch. Help me
THe problem is I am drawing some rectangle and lines inside the canvas
but I have to repaint the existing geometrical images along with the new one, but but but
I want to only draw the new object ONLY without redrawing the older ones. that is when I draw some object say RECTANGLE after drawing the CIRCLE and repaint the CIRCLE vanishes.
I AM TRYING TO AVOID VECTORS.
HELP ME FRIENDS

Answer 1

Why don't you keep an area object (Shape) that will contains all your previous as well as the new shapes so that you need not to draw all shapes everytime.
See this demo if you like...
import java.awt.*;
import javax.swing.*;
import java.awt.geom.*;
import java.awt.event.*;
public class MyCanvas extends Canvas {
     Area area = new Area();
     static MyCanvas canvas = new MyCanvas();
     public MyCanvas(){
          draw(new Ellipse2D.Double(10,10,50,50));
     public void draw(Shape shape){
          area.add(new Area(shape));
          repaint();
     public void paint(Graphics g) {
          super.paint( g);
          Graphics2D g2 = (Graphics2D)g;
          g2.draw(area);
     public static void main(String[] args) {
          JFrame f = new JFrame("Shape demo");
          f.getContentPane().add(canvas, BorderLayout.CENTER);
          JButton button = new JButton("add rectangel");
          button.addActionListener(new ActionListener() {
               public void actionPerformed(ActionEvent e) {
                    Rectangle r = new Rectangle(10,100, 100,50);
                    canvas.draw(r);
          f.getContentPane().add(button, BorderLayout.SOUTH);
          f.setSize(500,300);
          f.setLocation(200,200);
          f.show();
}