Undo Draw rect

[Mohamed Farouk]

Hello Friends
I have an image in a panel where i try ot draw a rect over the image the the rectangle gets drawn properly. Now i want to clear the rect which was created just now is it possible?

Thanks
Farouk

[Ulf Dittmer]

This is more of a GUI question, not an applet question, so I'm moving it to our AWT/Swing/GUI forum. Please find the thread there and continue the discussion.

[Jeff Albertson]

I would define a component to have an image and a rectangle, and have its paintComponent method render them both. To cause the rectangle to disappear set it to null:

myComp.setRectangle(null); //should call repaint

[Mohamed Farouk]

Hello Jeff
Thank you very much for your reply, now I am not sure how to do this can you give me an small code example. My component is a panel currently which in its paint method draws the image and this rectangle currently is drawn on the panel graphics is the mouse dragged along now how can i make the change you mentioned in this scenario?

[Jeff Albertson]

import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
 

public class PanelWithRectangle extends JPanel {
    private Rectangle rectangle;
 
    private static Rectangle copyRectangle(Rectangle r){
return r == null ? null : new Rectangle(r);
}
 
    public Rectangle getRectangle() {
return copyRectangle(rectangle);
}
 
public void setRectangle(Rectangle rectangle) {
this.rectangle = copyRectangle(rectangle);
repaint();
}
 
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
if (rectangle != null){
g2.draw(rectangle);
}
}
 
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable(){
public void run() {
gui();
}
});
}
 
static void gui() {
final PanelWithRectangle comp = new PanelWithRectangle();
comp.setPreferredSize(new Dimension(300,200));
JPanel south = new JPanel();
JButton add = new JButton("random rectangle");
south.add(add);
add.addActionListener(new ActionListener(){
Random rnd = new Random();
 
public void actionPerformed(ActionEvent evt) {
int x = rnd.nextInt(comp.getWidth());
int y = rnd.nextInt(comp.getHeight());
int w = rnd.nextInt(100);
int h = rnd.nextInt(100);
comp.setRectangle(new Rectangle(x, y, w, h));
}
});
JButton clear = new JButton("clear rectangle");
south.add(clear);
clear.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent evt) {
comp.setRectangle(null);
}
});
 
JFrame f = new JFrame("PanelWithRectangle");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Container cp = f.getContentPane();
cp.add(comp, BorderLayout.CENTER);
cp.add(south, BorderLayout.SOUTH);
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);
}
}