GUI program which performs Shear , Scale, Translate and Rotate affineTransforms on an image

AffineTransformGUI.java

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package assignment11;

import images.*;
import assignment11.ImagePreviewPanel;
import java.awt.Graphics;
import java.awt.Window;
import java.awt.geom.AffineTransform;
import java.awt.geom.Point2D;
import java.awt.geom.Rectangle2D;
import java.awt.image.AffineTransformOp;
import java.awt.image.BufferedImage;
import java.awt.image.BufferedImageOp;
import java.io.File;
import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.imageio.ImageIO;
import javax.swing.Icon;
import javax.swing.ImageIcon;
import javax.swing.JFileChooser;

/**
 *
 * @author Vineetrok
 */
public class AffineTransformGUI extends javax.swing.JFrame {

    BufferedImage mainImage, copyOfMainImage, transformedImage, blackImage, backupImage;
    double transX, transY, theta, rotateX, rotateY, shearX, shearY,scaleX,scaleY;
    int imageWidth, imageHeight;
    String selection = "Select Transition";

    /**
     * Creates new form AffineTransformGUI
     */
    public AffineTransformGUI() {
        initComponents();

    }

    /**
     * This method is called from within the constructor to initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is always
     * regenerated by the Form Editor.
     */
    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">//GEN-BEGIN:initComponents
    private void initComponents() {

        FileChooser = new javax.swing.JFileChooser();
        mainPanel = new javax.swing.JPanel();
        ResetBtn = new javax.swing.JButton();
        XSlider = new javax.swing.JSlider();
        ClearBtn = new javax.swing.JButton();
        ExitBtn = new javax.swing.JButton();
        YSlider = new javax.swing.JSlider();
        TransformationList = new javax.swing.JComboBox();
        displayLabel = new javax.swing.JLabel();
        jMenuBar1 = new javax.swing.JMenuBar();
        FileMenu = new javax.swing.JMenu();
        Open = new javax.swing.JMenuItem();
        Save = new javax.swing.JMenuItem();
        AboutMe = new javax.swing.JMenu();

        ImagePreviewPanel preview = new ImagePreviewPanel();
        FileChooser.setAccessory(preview);
        FileChooser.addPropertyChangeListener(preview);
        FileChooser.setCurrentDirectory(new java.io.File("D:\\M.Sc.I.T\\standard_test_images\\standard_test_images"));
        FileChooser.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                FileChooserActionPerformed(evt);
            }
        });

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
        setTitle("Affine Transforms Demo");
        setResizable(false);

        mainPanel.setBackground(new java.awt.Color(51, 51, 51));
        mainPanel.setPreferredSize(new java.awt.Dimension(300, 300));

        ResetBtn.setFont(new java.awt.Font("Gotham Medium", 0, 14)); // NOI18N
        ResetBtn.setText("RESET");
        ResetBtn.setPreferredSize(new java.awt.Dimension(80, 20));
        ResetBtn.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                ResetBtnActionPerformed(evt);
            }
        });

        XSlider.setBackground(new java.awt.Color(51, 51, 51));
        XSlider.setForeground(new java.awt.Color(255, 255, 255));
        XSlider.setPaintLabels(true);
        XSlider.setPaintTicks(true);
        XSlider.addChangeListener(new javax.swing.event.ChangeListener() {
            public void stateChanged(javax.swing.event.ChangeEvent evt) {
                XSliderStateChanged(evt);
            }
        });

        ClearBtn.setFont(new java.awt.Font("Gotham Medium", 0, 14)); // NOI18N
        ClearBtn.setText("CLEAR");
        ClearBtn.setPreferredSize(new java.awt.Dimension(80, 20));
        ClearBtn.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                ClearBtnActionPerformed(evt);
            }
        });

        ExitBtn.setFont(new java.awt.Font("Gotham Medium", 0, 14)); // NOI18N
        ExitBtn.setText("EXIT");
        ExitBtn.setPreferredSize(new java.awt.Dimension(80, 20));
        ExitBtn.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                ExitBtnActionPerformed(evt);
            }
        });

        YSlider.setBackground(new java.awt.Color(51, 51, 51));
        YSlider.setForeground(new java.awt.Color(255, 255, 255));
        YSlider.setOrientation(javax.swing.JSlider.VERTICAL);
        YSlider.setPaintLabels(true);
        YSlider.setPaintTicks(true);
        YSlider.addChangeListener(new javax.swing.event.ChangeListener() {
            public void stateChanged(javax.swing.event.ChangeEvent evt) {
                YSliderStateChanged(evt);
            }
        });

        TransformationList.setModel(new javax.swing.DefaultComboBoxModel(new String[] { "Select Transition", "Translation", "Shear", "Rotate", "Scale" }));
        TransformationList.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                TransformationListActionPerformed(evt);
            }
        });

        displayLabel.setBackground(new java.awt.Color(204, 204, 204));
        displayLabel.setHorizontalTextPosition(javax.swing.SwingConstants.CENTER);
        displayLabel.setIconTextGap(0);
        displayLabel.setMaximumSize(new java.awt.Dimension(300, 300));

        javax.swing.GroupLayout mainPanelLayout = new javax.swing.GroupLayout(mainPanel);
        mainPanel.setLayout(mainPanelLayout);
        mainPanelLayout.setHorizontalGroup(
            mainPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(mainPanelLayout.createSequentialGroup()
                .addGroup(mainPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addGroup(mainPanelLayout.createSequentialGroup()
                        .addGap(32, 32, 32)
                        .addComponent(TransformationList, javax.swing.GroupLayout.PREFERRED_SIZE, 206, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                        .addGroup(mainPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
                            .addComponent(ResetBtn, javax.swing.GroupLayout.DEFAULT_SIZE, 84, Short.MAX_VALUE)
                            .addComponent(ClearBtn, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                            .addComponent(ExitBtn, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)))
                    .addGroup(mainPanelLayout.createSequentialGroup()
                        .addGap(24, 24, 24)
                        .addGroup(mainPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                            .addGroup(mainPanelLayout.createSequentialGroup()
                                .addComponent(XSlider, javax.swing.GroupLayout.PREFERRED_SIZE, 300, javax.swing.GroupLayout.PREFERRED_SIZE)
                                .addGap(0, 0, Short.MAX_VALUE))
                            .addGroup(mainPanelLayout.createSequentialGroup()
                                .addComponent(displayLabel, javax.swing.GroupLayout.PREFERRED_SIZE, 300, javax.swing.GroupLayout.PREFERRED_SIZE)
                                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                                .addComponent(YSlider, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)))))
                .addContainerGap(18, javax.swing.GroupLayout.PREFERRED_SIZE))
        );
        mainPanelLayout.setVerticalGroup(
            mainPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, mainPanelLayout.createSequentialGroup()
                .addGap(49, 49, 49)
                .addGroup(mainPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
                    .addComponent(YSlider, javax.swing.GroupLayout.PREFERRED_SIZE, 300, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addComponent(displayLabel, javax.swing.GroupLayout.PREFERRED_SIZE, 300, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                .addComponent(XSlider, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 13, Short.MAX_VALUE)
                .addGroup(mainPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(ResetBtn, javax.swing.GroupLayout.PREFERRED_SIZE, 25, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addComponent(TransformationList, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addGap(13, 13, 13)
                .addComponent(ClearBtn, javax.swing.GroupLayout.PREFERRED_SIZE, 25, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                .addComponent(ExitBtn, javax.swing.GroupLayout.PREFERRED_SIZE, 25, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGap(45, 45, 45))
        );

        jMenuBar1.setBorder(null);

        FileMenu.setMnemonic('F');
        FileMenu.setText("File");
        FileMenu.setFont(new java.awt.Font("Gotham Medium", 0, 11)); // NOI18N

        Open.setFont(new java.awt.Font("Gotham Medium", 0, 11)); // NOI18N
        Open.setMnemonic('O');
        Open.setText("Open");
        Open.setOpaque(false);
        Open.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                OpenActionPerformed(evt);
            }
        });
        FileMenu.add(Open);

        Save.setText("Save");
        Save.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                SaveActionPerformed(evt);
            }
        });
        FileMenu.add(Save);

        jMenuBar1.add(FileMenu);

        AboutMe.setText("About Me");
        AboutMe.setFont(new java.awt.Font("Gotham Medium", 0, 11)); // NOI18N
        jMenuBar1.add(AboutMe);

        setJMenuBar(jMenuBar1);

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addComponent(mainPanel, javax.swing.GroupLayout.DEFAULT_SIZE, 403, Short.MAX_VALUE)
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addComponent(mainPanel, javax.swing.GroupLayout.PREFERRED_SIZE, 549, javax.swing.GroupLayout.PREFERRED_SIZE)
        );

        pack();
    }// </editor-fold>//GEN-END:initComponents

    private void ResetBtnActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_ResetBtnActionPerformed
        // TODO add your handling code here:
        if (backupImage != null) {
            paintImage(backupImage);
        }
    }//GEN-LAST:event_ResetBtnActionPerformed

    private void ClearBtnActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_ClearBtnActionPerformed
        // TODO add your handling code here:
        paintImage(blackImage);

    }//GEN-LAST:event_ClearBtnActionPerformed

    private void ExitBtnActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_ExitBtnActionPerformed
        // TODO add your handling code here:
        System.exit(0);
    }//GEN-LAST:event_ExitBtnActionPerformed

    private void OpenActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_OpenActionPerformed
        // TODO add your handling code here:
        int returnVal = FileChooser.showOpenDialog(this);
        if (returnVal == JFileChooser.APPROVE_OPTION) {
            File file = FileChooser.getSelectedFile();
            try {
                backupImage = mainImage = ImageIO.read(file);
            } catch (IOException ex) {
                Logger.getLogger(AffineTransformGUI.class.getName()).log(Level.SEVERE, null, ex);
            }


            transformedImage = new BufferedImage(displayLabel.getWidth(), displayLabel.getHeight(), BufferedImage.TYPE_INT_RGB);
            blackImage = new BufferedImage(displayLabel.getWidth(), displayLabel.getHeight(), BufferedImage.TYPE_INT_RGB);
            blackImage.setRGB(51, 51, 51);
            paintImage(mainImage);


        } else {
            System.out.println("File access cancelled by user.");
        }
    }//GEN-LAST:event_OpenActionPerformed

    private void FileChooserActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_FileChooserActionPerformed
        // TODO add your handling code here:
    }//GEN-LAST:event_FileChooserActionPerformed

    private void TransformationListActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_TransformationListActionPerformed
        // TODO add your handling code here:
        selection = (String) TransformationList.getSelectedItem();
        System.out.println(selection);
        if (selection == "Scale") {
            if(YSlider.isEnabled()==false){
                YSlider.setEnabled(true);
            }
            XSlider.setMaximum(20);
            XSlider.setMinimum(1);
            YSlider.setMaximum(20);
            YSlider.setMinimum(1);
            XSlider.setValue(1);
            YSlider.setValue(1);
            

        } else if (selection == "Rotate") {
            YSlider.setEnabled(false);
            XSlider.setMaximum(360);
            XSlider.setMinimum(0);
            XSlider.setValue(0);

        } else if (selection == "Translation") {
            YSlider.setEnabled(true);
            XSlider.setMaximum(300);
            XSlider.setMinimum(-300);
            YSlider.setMaximum(300);
            YSlider.setMinimum(-300);
            XSlider.setMajorTickSpacing(0);
            YSlider.setValue(0);
        } else if (selection == "Shear") {
            YSlider.setEnabled(true);
            XSlider.setMaximum(5000);
            XSlider.setMinimum(0);
            YSlider.setMaximum(5000);
            YSlider.setMinimum(0);
        }
    }//GEN-LAST:event_TransformationListActionPerformed

    private void XSliderStateChanged(javax.swing.event.ChangeEvent evt) {//GEN-FIRST:event_XSliderStateChanged
        // TODO add your handling code here:
        if (selection == "Translation") {
            transX = XSlider.getValue();
            translateFunction(transY, transY);
        } else if (selection == "Rotate") {
            theta = XSlider.getValue();
            theta = Math.toRadians(theta);
            rotateFunction(theta);

        } else if (selection == "Shear") {
            shearX = XSlider.getValue();
            shearFunction(shearX, shearY);
        } else if (selection == "Scale") {
            scaleX= XSlider.getValue();
            scaleFunction(scaleX/10, scaleY/10);
        }
    }//GEN-LAST:event_XSliderStateChanged

    private void YSliderStateChanged(javax.swing.event.ChangeEvent evt) {//GEN-FIRST:event_YSliderStateChanged
        // TODO add your handling code here:

        if (selection == "Translation") {
            transY = YSlider.getValue();
            translateFunction(transX, transY);
        } else if (selection == "Shear") {
            shearY = YSlider.getValue();
            shearFunction(shearX, shearY);
        } else if (selection == "Scale") {
            
            scaleY= YSlider.getValue();
            
            scaleFunction(scaleX/10, scaleY/10);
        }
    }//GEN-LAST:event_YSliderStateChanged

    private void SaveActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_SaveActionPerformed
        // TODO add your handling code here:
        
        Graphics saveImage  = transformedImage.getGraphics();
        BufferedImage saveBufferedImage = new BufferedImage(displayLabel.getHeight(), displayLabel.getWidth(), BufferedImage.TYPE_INT_ARGB);
        saveImage.drawImage(saveBufferedImage, 0, 0, null);
        File f = new File("AffineTransformedImage.png");
        try {
            ImageIO.write(saveBufferedImage,"PNG" , f);
        } catch (IOException ex) {
            Logger.getLogger(AffineTransformGUI.class.getName()).log(Level.SEVERE, null, ex);
        }
    }//GEN-LAST:event_SaveActionPerformed
    
    public void scaleFunction(double scaleX,double scaleY){
        try{
            AffineTransform tx = AffineTransform.getScaleInstance(scaleX, scaleY);
//            tx.scale(scaleX, scaleY);
            BufferedImage scaleImage = new BufferedImage(mainImage.getWidth(), mainImage.getHeight(), mainImage.getType());
            BufferedImageOp scaleOp = new AffineTransformOp(tx, AffineTransformOp.TYPE_BILINEAR);
            scaleOp.filter(mainImage, scaleImage);
            paintImage(blackImage);
            paintImage(scaleImage);
        }catch (Exception e) {
             System.out.println("Scaling exception = " + e);
            AffineTransform tx = AffineTransform.getScaleInstance(0.1, 0.1);
//            tx.scale(scaleX, scaleY);
            BufferedImage scaleImage = new BufferedImage(mainImage.getWidth(), mainImage.getHeight(), mainImage.getType());
            BufferedImageOp scaleOp = new AffineTransformOp(tx, AffineTransformOp.TYPE_BILINEAR);
            scaleOp.filter(mainImage, scaleImage);
            paintImage(blackImage);
            paintImage(scaleImage);
        }
    }
    
    public void shearFunction(double shearX, double shearY) {
        try {
            AffineTransform tx = AffineTransform.getShearInstance(shearX / 1000, shearY / 1000);
            Rectangle2D box = getBoundingBox(mainImage, tx);
            AffineTransform shearing = AffineTransform.getTranslateInstance(-box.getMinX(), -box.getMinY());
            tx.preConcatenate(shearing);
            BufferedImage shearImage = new BufferedImage((int) Math.round(box.getWidth()), (int) Math.round(box.getHeight()), mainImage.getType());
            BufferedImageOp shearOp = new AffineTransformOp(tx, AffineTransformOp.TYPE_BILINEAR);
            shearOp.filter(mainImage, shearImage);
            paintImage(blackImage);
            paintImage(shearImage);
        } catch (Exception e) {
            System.out.println("Shearing exception = " + e);
            // Reset back to default
            AffineTransform tx =
                    AffineTransform.getShearInstance(0.0, 0.0);
            Rectangle2D box = getBoundingBox(mainImage, tx);
            AffineTransform shearing = AffineTransform.getTranslateInstance(-box.getMinX(), -box.getMinY());
            tx.preConcatenate(shearing);
            BufferedImage shearImage = new BufferedImage((int) Math.round(box.getWidth()), (int) Math.round(box.getHeight()), mainImage.getType());
            BufferedImageOp shearOp = new AffineTransformOp(tx, AffineTransformOp.TYPE_BILINEAR);
            shearOp.filter(mainImage, shearImage);
            paintImage(blackImage);
            paintImage(shearImage);
        }
    }

    public void rotateFunction(double theta) {
        AffineTransform tx = AffineTransform.getRotateInstance(theta);
        Rectangle2D box = getBoundingBox(mainImage, tx);
        AffineTransform translation = AffineTransform.getTranslateInstance(-box.getMinX(), -box.getMinY());
        tx.preConcatenate(translation);
        int width = (int) Math.round(box.getWidth());
        int height = (int) Math.round(box.getHeight());
        BufferedImage rotatedImage = new BufferedImage(width, height, mainImage.getType());
        BufferedImageOp rotateOp = new AffineTransformOp(tx, AffineTransformOp.TYPE_BILINEAR);
        rotateOp.filter(mainImage, rotatedImage);
        paintImage(blackImage);
        paintImage(rotatedImage);
        transformedImage=rotatedImage;
    }

    public void translateFunction(double transX1, double transY1) {
        AffineTransform tx = new AffineTransform();
        tx.translate(transX, transY);
        BufferedImage translateImage = new BufferedImage(mainImage.getWidth(), mainImage.getHeight(), mainImage.getType());
        BufferedImageOp translateOp = new AffineTransformOp(tx, AffineTransformOp.TYPE_BILINEAR);
        translateOp.filter(mainImage, translateImage);
        paintImage(blackImage);
        paintImage(translateImage);
    }

    public void paintImage(BufferedImage image) {
//        ImageIcon icon = new ImageIcon(image);
        displayLabel.setVerticalAlignment((int) CENTER_ALIGNMENT);
        displayLabel.setHorizontalAlignment((int) CENTER_ALIGNMENT);
        //displayLabel.setIcon(new ImageIcon(blackImage));
        if (mainImage.getHeight() > displayLabel.getHeight() || mainImage.getWidth() > displayLabel.getWidth()) {
            displayLabel.setIcon(new ImageIcon(image.getScaledInstance(displayLabel.getWidth(), displayLabel.getHeight(), image.SCALE_SMOOTH)));
        } else {
            displayLabel.setIcon(new ImageIcon(image));
        }
    }

    /**
     * @param args the command line arguments
     */
    public static void main(String args[]) {
        /*
         * Set the Nimbus look and feel
         */
        //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
        /*
         * If Nimbus (introduced in Java SE 6) is not available, stay with the
         * default look and feel. For details see
         * http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html
         */
        try {
            for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
                if ("Nimbus".equals(info.getName())) {
                    javax.swing.UIManager.setLookAndFeel(info.getClassName());
                    break;
                }
            }
        } catch (ClassNotFoundException ex) {
            java.util.logging.Logger.getLogger(AffineTransformGUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(AffineTransformGUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(AffineTransformGUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(AffineTransformGUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }
        //</editor-fold>

        /*
         * Create and display the form
         */
        
        java.awt.EventQueue.invokeLater(new Runnable() {

            public void run() {
               
                new AffineTransformGUI().setVisible(true);
            }
        });
    }
    // Variables declaration - do not modify//GEN-BEGIN:variables
    public javax.swing.JMenu AboutMe;
    public javax.swing.JButton ClearBtn;
    public javax.swing.JButton ExitBtn;
    public javax.swing.JFileChooser FileChooser;
    public javax.swing.JMenu FileMenu;
    public javax.swing.JMenuItem Open;
    public javax.swing.JButton ResetBtn;
    public javax.swing.JMenuItem Save;
    public javax.swing.JComboBox TransformationList;
    public javax.swing.JSlider XSlider;
    public javax.swing.JSlider YSlider;
    public javax.swing.JLabel displayLabel;
    public javax.swing.JMenuBar jMenuBar1;
    public javax.swing.JPanel mainPanel;
    // End of variables declaration//GEN-END:variables

    private Rectangle2D getBoundingBox(BufferedImage image, AffineTransform tx) {
        int xmax = image.getWidth() - 1;
        int ymax = image.getHeight() - 1;
        Point2D[] corners = new Point2D.Double[4];
        corners[0] = new Point2D.Double(0, 0);
        corners[1] = new Point2D.Double(xmax, 0);
        corners[2] = new Point2D.Double(xmax, ymax);
        corners[3] = new Point2D.Double(0, ymax);
        tx.transform(corners, 0, corners, 0, 4);

//Calculat e bounding box of transformed corner points

        Rectangle2D boundingBox = new Rectangle2D.Double();
        for (int i = 0; i < 4; ++i) {
            boundingBox.add(corners[i]);
        }

        return boundingBox;
    }
}

ImagePreviewPanel.java

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */

package assignment11;

/**
 *
 * @author Vineetrok
 */
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.beans.*;
import java.io.File;
 
public class ImagePreviewPanel extends JPanel
        implements PropertyChangeListener {
    
    private int width, height;
    private ImageIcon icon;
    private Image image;
    private static final int ACCSIZE = 155;
    private Color bg;
    
    public ImagePreviewPanel() {
        setPreferredSize(new Dimension(ACCSIZE, -1));
        bg = getBackground();
    }
    
    public void propertyChange(PropertyChangeEvent e) {
        String propertyName = e.getPropertyName();
        
        // Make sure we are responding to the right event.
        if (propertyName.equals(JFileChooser.SELECTED_FILE_CHANGED_PROPERTY)) {
            File selection = (File)e.getNewValue();
            String name;
            
            if (selection == null)
                return;
            else
                name = selection.getAbsolutePath();

            if ((name != null) &&
                    name.toLowerCase().endsWith(".jpg") ||
                    name.toLowerCase().endsWith(".jpeg") ||
                    name.toLowerCase().endsWith(".gif") ||
                    name.toLowerCase().endsWith(".png")) {
                icon = new ImageIcon(name);
                image = icon.getImage();
                scaleImage();
                repaint();
            }
        }
    }
    
    private void scaleImage() {
        width = image.getWidth(this);
        height = image.getHeight(this);
        double ratio = 1.0;

        if (width >= height) {
            ratio = (double)(ACCSIZE-5) / width;
            width = ACCSIZE-5;
            height = (int)(height * ratio);
        }
        else {
            if (getHeight() > 150) {
                ratio = (double)(ACCSIZE-5) / height;
                height = ACCSIZE-5;
                width = (int)(width * ratio);
            }
            else {
                ratio = (double)getHeight() / height;
                height = getHeight();
                width = (int)(width * ratio);
            }
        }
                
        image = image.getScaledInstance(width, height, Image.SCALE_DEFAULT);
    }
    
    public void paintComponent(Graphics g) {
        g.setColor(bg);
        

        g.fillRect(0, 0, ACCSIZE, getHeight());
        g.drawImage(image, getWidth() / 2 - width / 2 + 5,
                getHeight() / 2 - height / 2, this);
    }
    
}