How to rotate the square in my swing app

Question

I have developed a little swing application in which i have drawn a square.Now i want to rotate this square at its center using Thread.The problem i'm having is how to get reference to that square in my rotateSquare() method. (Actually i need a method,if possible, to rotate the same square instead of wiping out the entire content pane and drawing another rotated square at its position).

Here is my code:

import java.awt.Color;
import java.awt.Container;
import java.awt.Graphics;
import java.awt.Graphics2D;

import javax.swing.JFrame;
import javax.swing.SwingUtilities;


public class Rotation extends JFrame implements Runnable{
Thread t;
Rotation()
{
    super("Animation of rotation about center");
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    setSize(400,400);

    setContentPane(new Container(){
        public void paint(Graphics g)
        {
            Graphics2D g2=(Graphics2D)g.create();
            g2.setBackground(Color.WHITE);
            g2.clearRect(0, 0, getWidth(), getHeight());

            g2.setColor(Color.GRAY);
            g2.fillRect(100, 100, 100, 100);
        }
    });

    t=new Thread(this,"pr");
    t.start();


    setVisible(true);
    //setOpacity(0.8f);
}
public void run()
{
    try{
        for(;;)
        {
            Thread.sleep(100);
            SwingUtilities.invokeLater(new Runnable(){public void run(){
                rotateSquare();
            }});
        }
    }catch(InterruptedException e){System.out.println("Thread interrupted");}
}
public void rotateSquare();
{

}
public static void main(String args[])
{
    //setDefaultLookAndFeelDecorated(true);
    SwingUtilities.invokeLater(new Runnable(){public void run(){new Rotation();}});
}

}

score 3 · Accepted Answer · answered Oct 24 '12 at 12:03

3

see AffineTransform
add parameters AffineTransform.rotate(intDegrees);
fit rotated Object to the parents bounds myAffineTransform.translate(getWidth(), getHeight())
then returns back Graphics2D#transform(myAffineTransform);
use Swing Timer instead of Runnable#Thread with Thread.sleep(int), that caused freeze or flickering for Graphics2D and locked EventDispatchThread untill endless Thread ended (never ending in your case)

answered Oct 24 '12 at 12:03

mKorbel

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can anyone please type a bit of code so that i know exactly what to do as i'm not much experienced with Java 2D Graphics. – Naveen Oct 24 '12 at 12:31
`Timer` is alternative to `Thread`, for [example](http://stackoverflow.com/a/3420651/230513). – trashgod Oct 24 '12 at 16:53

score 0 · Answer 2 · answered Oct 24 '12 at 11:58

You should define a Square class that would include code defining a square object. This would have a draw(Graphics g) method that would know how to draw the Square.

In your other class, you would have a reference to a Square object. Under the paint method you would call square.draw(g).

This way, you can apply the rotation under the Square draw() method.

How to rotate the square in my swing app

2 Answers2