Zoom in and zoom out function in Jpanel

Question

I have to add Zoom In and Zoom Out functionality to JPanel, which contains components like JLabel with ImageIcon.

I want to Zoom JPanel with their components appropriately I tried with following code snippet but it did not work properly.

The JPanel which is having null layout and is itself placed inside an Applet. I am unsure of the reason as to why it is not working either because of Applet or something else !!

cPanel is my JPanel which contains JLabel

Following code snippet on Zoom Button click, it shows blink screen on button click after that as original

Graphics g = cPanel.getGraphics();
Graphics2D g2d = (Graphics2D) g;
AffineTransform savedXForm = g2d.getTransform();
g2d.scale(1.0, 1.0);
g2d.setColor(Color.red);
super.paint(g);
g2d.setTransform(savedXForm);
cPanel.validate();
cPanel.repaint();

*"i want to zoom in and zoom"* I want questions to be easy to read. Please stop 'mumbling' add an upper case letter to the start of sentences. — Andrew Thompson, May 02 '13 at 07:06
I'd take a look at your layout issues, then I'd take a look `JXLayer` — MadProgrammer, May 02 '13 at 07:11
See ***[this](http://stackoverflow.com/questions/2944442/zoom-in-java-swing-application?rq=1)*** post — Extreme Coders, May 02 '13 at 07:15
@ExtremeCoders +1 for suggestion, shame the links are broken... ;) — MadProgrammer, May 02 '13 at 07:30
Please anyone tell me what i did wrong, is there any other solution to do it or it not possible in applet because of null layout i set to jpanel — YuvRAJ, May 02 '13 at 09:29

Sanjit Kumar Mishra · Answer 1 · 2016-05-20T09:22:13.203

You can have a look into this link: http://blog.sodhanalibrary.com/2015/04/zoom-in-and-zoom-out-image-using-mouse_9.html#.Vz6iG-QXV0w

Source Code to Refer(Here it has been accomplished using MouseWheelListener):

import java.awt.EventQueue;
import javax.imageio.ImageIO;
import javax.swing.Icon;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JScrollPane;
import java.awt.BorderLayout;
import javax.swing.JPanel;
import com.mortennobel.imagescaling.ResampleOp;
import java.awt.event.MouseWheelListener;
import java.awt.event.MouseWheelEvent;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;

public class ImageZoom {

    private JFrame frmImageZoomIn;
    private static final String inputImage = "C:\\my-pfl-pic.jpg"; // give image path here
    private JLabel label = null; 
    private double zoom = 1.0;  // zoom factor
    private BufferedImage image = null;
    /**
     * Launch the application.
     */
    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    ImageZoom window = new ImageZoom();
                    window.frmImageZoomIn.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }

    /**
     * Create the application.
     * @throws IOException 
     */
    public ImageZoom() throws IOException {
        initialize();
    }

    /**
     * Initialize the contents of the frame.
     * @throws IOException 
     */
    private void initialize() throws IOException {
        frmImageZoomIn = new JFrame();
        frmImageZoomIn.setTitle("Image Zoom In and Zoom Out");
        frmImageZoomIn.setBounds(100, 100, 450, 300);
        frmImageZoomIn.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        JScrollPane scrollPane = new JScrollPane();
        frmImageZoomIn.getContentPane().add(scrollPane, BorderLayout.CENTER);

        image = ImageIO.read(new File(inputImage));

        JPanel panel = new JPanel();
        panel.setLayout(new BorderLayout());

        // display image as icon 
        Icon imageIcon = new ImageIcon(inputImage);
        label = new JLabel( imageIcon );
        panel.add(label, BorderLayout.CENTER);

        panel.addMouseWheelListener(new MouseWheelListener() {
            public void mouseWheelMoved(MouseWheelEvent e) {
                int notches = e.getWheelRotation();
                double temp = zoom - (notches * 0.2);
                // minimum zoom factor is 1.0
                temp = Math.max(temp, 1.0);
                if (temp != zoom) {
                    zoom = temp;
                    resizeImage();
                }
            }
        });
        scrollPane.setViewportView(panel);
    }

    public void resizeImage() {
           System.out.println(zoom);
           ResampleOp  resampleOp = new ResampleOp((int)(image.getWidth()*zoom), (int)(image.getHeight()*zoom));
               BufferedImage resizedIcon = resampleOp.filter(image, null);
           Icon imageIcon = new ImageIcon(resizedIcon);
           label.setIcon(imageIcon);
        }


}

Zoom in and zoom out function in Jpanel

1 Answers1