Rotating image on the center of jpanel

Question

How to rotate image on it's center pivot and on the center of a jpanel ? I've tried to use this code, but the image only rotate on its center pivot on the top left of jpanel, but not on the center of the jpanel. Any help would be appreciated

public class aboutPanel extends javax.swing.JPanel {

Image img= new ImageIcon("ball.png").getImage();
Image ball[]=new Image[4];//result of cropping image
AffineTransform afft=new AffineTransform();
int degree=10;

public aboutPanel() {
    initComponents();
    for(int i=0;i<4;i++)//crop image to 4 ball
    {
        ball[i]=Toolkit.getDefaultToolkit().createImage(new FilteredImageSource(img.getSource(),new CropImageFilter(0,i*78,80,78)));
    }
    if(thr.isAlive()==false)
    {
        thr.start();//start thread
    }

}

Thread thr= new Thread(new Runnable() {
    @Override
    public void run() {
        while(true)
        {
            repaint();
            try {
                Thread.sleep(20);
            } catch (InterruptedException ex) {
                Logger.getLogger(aboutPanel.class.getName()).log(Level.SEVERE, null, ex);
            }
        }
    }
});

@Override
public void paint(Graphics g) {
    super.paint(g); 
    Graphics2D g2d=(Graphics2D)g;
    afft.rotate(Math.toRadians(degree),ball[0].getWidth(this)/2,ball[0].getHeight(this)/2);
    g2d.setTransform(afft);
    g2d.drawImage(ball[0],0,0,this);         
    if(degree==360)
    {
        degree=0;
    } 
}

score 1 · Accepted Answer · answered Dec 11 '13 at 16:45

1

g2d.drawImage(ball[0],0,0,this);

You are drawing the image at location (0, 0);

If you want it in the center then you need to calculate the center. For example the width center would be something like:

int widthCenter = (getWidth() - ball[0].getWidth(this)) / 2;

answered Dec 11 '13 at 16:45

camickr

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A related approach is outlined [here](http://stackoverflow.com/a/13031824/230513). – trashgod Dec 12 '13 at 04:53
thanks, but now the ball is revolving around the 0,0 coordinate of the panel – SalacceoVanz Dec 12 '13 at 05:25
ohh, the rotate method should be like this afft.rotate(Math.toRadians(degree),getWidth()/2,getHeight()/2); My problem is solved...thx – SalacceoVanz Dec 12 '13 at 05:41

Rotating image on the center of jpanel

1 Answers1