How to adjust the scroll bar using the images zoomin and zoomout in swing

I want to adjust the scroll bar when the images zoom in and zoom out. My image display on JPanel and JScrollPane contains JPanel

Solution

For your updated questions:

You need to call setpreferredsize with the new image size (use this to test your application)

Change zoomin and zoomout from:

can.setSize(imgSize);

To:

can.setPreferredSize(imgSize);

example

You need to update the slider to change the preferred size I wrote a small program (the following code) to generate this screenshot (with zoom control):

Image component code:

static class ImageComponent extends JComponent {

    final BufferedImage img;

    public ImageComponent(URL url) throws IOException {
        img = ImageIO.read(url);
        setZoom(1);
    }

    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        Dimension dim = getPreferredSize();
        g.drawImage(img,dim.width,dim.height,this);
    }

    private void setZoom(double zoom) {
        int w = (int) (zoom * img.getWidth());
        int h = (int) (zoom * img.getHeight());
        setPreferredSize(new Dimension(w,h));
        revalidate();
        repaint();
    }
}

Main program:

public static void main(String[] args) throws Exception {

    final URL lenna =
        new URL("http://upload.wikimedia.org/wikipedia/en/2/24/Lenna.png");

    final JSlider slider = new JSlider(0,1000,500);
    final ImageComponent image = new ImageComponent(lenna);
    slider.addchangelistener(new changelistener() {
        @Override
        public void stateChanged(ChangeEvent e) {
            image.setZoom(2. * slider.getValue() / slider.getMaximum());
        }
    });

    JFrame frame = new JFrame("Test");
    frame.add(slider,BorderLayout.NORTH);

    frame.add(new JScrollPane(image));

    frame.setDefaultCloSEOperation(JFrame.EXIT_ON_CLOSE);
    frame.setSize(400,300);
    frame.setVisible(true);
}