Backup for image that is drawn on in Java

In my application, there are things marked on an image by clicking on the image.
That is done by setting the image as an Icon to a JLabel and adding a MousePressed method
I want to add a feature for the users to redo the last step now and need a backupimage for that.

The following is a code example:

import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.Toolkit;
import java.awt.geom.AffineTransform;
import java.awt.image.AffineTransformOp;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import java.awt.Color;
import javax.swing.JButton;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;

public class BuffImgTest {

    private BufferedImage buffimg, scaledimg, backupscaledimg;
    private Image img;
    private JFrame frame;

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    BuffImgTest window = new BuffImgTest();
                    window.frame.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }

    public BuffImgTest() {
        initialize();
    }

    private void initialize() {
        frame = new JFrame();
        frame.setBounds(100, 100, 450, 300);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().setLayout(null);

        final JLabel label = new JLabel("");
        label.addMouseListener(new MouseAdapter() {
            @Override
            public void mousePressed(MouseEvent arg0) {
                Graphics graphics = scaledimg.getGraphics();
                graphics.setColor(Color.RED);
                graphics.drawString("Test", arg0.getX(), arg0.getY());
                Image img = Toolkit.getDefaultToolkit().createImage(
                        scaledimg.getSource());
                label.setIcon(new ImageIcon(img));
            }
        });

        label.setBounds(10, 34, 414, 201);

        try {
            buffimg = ImageIO.read(new File("test.jpg"));
            scaledimg = getScaledImage(buffimg, label.getWidth(),
                    label.getHeight());

            backupscaledimg = scaledimg;
            // backupscaledimg=getScaledImage(buffimg,label.getWidth(),label.getHeight());
            Image img = Toolkit.getDefaultToolkit().createImage(
                    scaledimg.getSource());
            label.setIcon(new ImageIcon(img));

        } catch (Exception e) {
            System.out.println(e);
        }
        frame.getContentPane().add(label);

        JButton btnNewButton = new JButton("Restart Step");
        btnNewButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent arg0) {
                scaledimg = backupscaledimg;
                Image img = Toolkit.getDefaultToolkit().createImage(
                        scaledimg.getSource());
                label.setIcon(new ImageIcon(img));
            }
        });
        btnNewButton.setBounds(111, 238, 89, 23);
        frame.getContentPane().add(btnNewButton);
    }

    public static BufferedImage getScaledImage(BufferedImage image, int width,
            int height) throws IOException {
        int imageWidth = image.getWidth();
        int imageHeight = image.getHeight();
        double scaleX = (double) width / imageWidth;
        double scaleY = (double) height / imageHeight;
        AffineTransform scaleTransform = AffineTransform.getScaleInstance(
                scaleX, scaleY);
        AffineTransformOp bilinearScaleOp = new AffineTransformOp(
                scaleTransform, AffineTransformOp.TYPE_BILINEAR);
        return bilinearScaleOp.filter(image, new BufferedImage(width, height,
                image.getType()));
    }
}

It is not working as intended.

If I use the commented line backupscaledimg = getScaledImage(buffimg,label.getWidth(),label.getHeight()); instead of backupscaledimg = scaledimg;, it is working as expected.

The problem is that I want to do several steps of drawing things on the image, and it can only be redone the first time like that. From what I know the problem might be, that the command backupscaledimg = scaledimg is only creating a pointer for backupscaledimg pointing to scaledimg which results in both of them altering.

I don't want to save a new imagefile on each step though.
Is there any way around this? (found the scaling function on here by the way thanks for that anonymous)

Solution

Made some changes

Using GridBagLayout
Able to reset back to original image by pressing "Restart Step"
Able to undo last action with the use of an image stack (i.e. a Stack of BufferedImage)

Example code:

import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Image;
import java.awt.Insets;
import java.awt.Toolkit;
import java.awt.geom.AffineTransform;
import java.awt.image.AffineTransformOp;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.Stack;

import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;

import java.awt.Color;

import javax.swing.JButton;

import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;

public class BuffImgTest {

    private BufferedImage scaledImg, originalScaledImg;
    private JFrame frame;

    private Stack<BufferedImage> imageStack = new Stack<>();

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    BuffImgTest window = new BuffImgTest();
                    window.frame.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }

    public BuffImgTest() {
        initialize();
    }

    private void initialize() {
        frame = new JFrame();
        frame.setBounds(100, 100, 450, 300);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().setLayout(new BorderLayout());

        JPanel panel = new JPanel(new GridBagLayout());

        final JLabel imgLabel = new JLabel("");
        imgLabel.addMouseListener(new MouseAdapter() {
            @Override
            public void mousePressed(MouseEvent arg0) {

                // Add current image to the image stack
                imageStack.add(copyImage(scaledImg));

                // Change the image
                Graphics graphics = scaledImg.getGraphics();
                graphics.setColor(Color.BLACK);
                graphics.setFont(new Font("Arial", Font.BOLD, 32));
                graphics.drawString("TEST", arg0.getX(), arg0.getY());

                // Update label
                Image img = Toolkit.getDefaultToolkit().createImage(
                        scaledImg.getSource());
                imgLabel.setIcon(new ImageIcon(img));
            }
        });

        imgLabel.setSize(500, 500);
        imgLabel.setPreferredSize(new Dimension(500, 500));

        try {
            BufferedImage buffImg = ImageIO.read(new File("test.jpg"));

            scaledImg = getScaledImage(buffImg, imgLabel.getWidth(),
                    imgLabel.getHeight());

            // Clone it first
            originalScaledImg = copyImage(scaledImg);

            Image img = Toolkit.getDefaultToolkit().createImage(
                    scaledImg.getSource());
            imgLabel.setIcon(new ImageIcon(img));

        } catch (Exception e) {
            System.out.println(e);
        }

        GridBagConstraints c = new GridBagConstraints();
        c.gridx = 0;
        c.gridy = 0;
        c.insets = new Insets(20, 10, 10, 10);
        panel.add(imgLabel, c);

        JButton restartBtn = new JButton("Restart Step");
        restartBtn.setFont(new Font("Arial", Font.ITALIC, 20));
        restartBtn.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent arg0) {

                // Clear the image stack
                imageStack.clear();

                // Reset the image
                scaledImg = copyImage(originalScaledImg);

                Image img = Toolkit.getDefaultToolkit().createImage(
                        scaledImg.getSource());
                imgLabel.setIcon(new ImageIcon(img));
            }
        });

        c = new GridBagConstraints();
        c.gridx = 0;
        c.gridy = 1;
        c.anchor = GridBagConstraints.CENTER;
        c.insets = new Insets(10, 10, 5, 10);
        panel.add(restartBtn, c);

        JButton undoBtn = new JButton("Undo Last");
        undoBtn.setFont(new Font("Arial", Font.ITALIC, 20));
        undoBtn.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent arg0) {

                if(imageStack.isEmpty()) {
                    JOptionPane.showMessageDialog(frame, "Cannot undo anymore!");
                    return;
                }           

                // Get the previous image
                scaledImg = copyImage(imageStack.pop());

                Image img = Toolkit.getDefaultToolkit().createImage(
                        scaledImg.getSource());
                imgLabel.setIcon(new ImageIcon(img));
            }
        });

        c = new GridBagConstraints();
        c.gridx = 0;
        c.gridy = 2;
        c.anchor = GridBagConstraints.CENTER;
        c.insets = new Insets(5, 10, 20, 10);
        panel.add(undoBtn, c);

        frame.getContentPane().add(panel, BorderLayout.CENTER);
        frame.setSize(800, 800);
    }

    /** For copying image */
    public static BufferedImage copyImage(BufferedImage source){
        BufferedImage b = new BufferedImage(
                source.getWidth(), source.getHeight(), source.getType());
        Graphics g = b.getGraphics();
        g.drawImage(source, 0, 0, null);
        g.dispose();
        return b;
    }

    public static BufferedImage getScaledImage(BufferedImage image, int width,
            int height) throws IOException {
        int imageWidth = image.getWidth();
        int imageHeight = image.getHeight();
        double scaleX = (double) width / imageWidth;
        double scaleY = (double) height / imageHeight;
        AffineTransform scaleTransform = AffineTransform.getScaleInstance(
                scaleX, scaleY);
        AffineTransformOp bilinearScaleOp = new AffineTransformOp(
                scaleTransform, AffineTransformOp.TYPE_BILINEAR);
        return bilinearScaleOp.filter(image, new BufferedImage(width, height,
                image.getType()));
    }
}

Edited Image:

Image after pressing "Restart step":

Pressing "Undo Last" when image stack is empty:

Note:

Code for copying image is from this answer by APerson