ImageProcessor.java

Below is the syntax highlighted version of ImageProcessor.java from §3.6 Case Study: Purple America.

/******************************************************************************
 *  Compilation:  javac ImageProcessor.java
 *  Execution:    java ImageProcessor
 *  Dependencies: Picture.java
 *
 *  GUI application for image processing. User can open a file from the
 *  local file system using a standard widget, apply various image
 *  processing filters (e.g., brighten, flip), and then save the resulting
 *  file using a standard widget.
 *
 *
 *  Limitations
 *  -----------
 *    - assumes that the user selects a valid picture format when opening
 *    - assumes that the user uses a valid extension when saving
 *
 *   Remarks
 *   -------
 *    - OS X users: to get the menus to appear at the top of the screen
 *                  (instead of the top of the frame), execute with:
 *
 *                  java -Dapple.laf.useScreenMenuBar=true ImageProcessor
 *
 ******************************************************************************/


import java.awt.Color;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;

import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JPanel;

import java.io.File;


public class ImageProcessor extends JFrame {
    private Picture pic = new Picture(256, 256);
    private JFileChooser chooser = new JFileChooser();

    // create the frame with an empty image
    public ImageProcessor() {
        setTitle("Image Processor 1.0");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setJMenuBar(createMenuBar());
        setResizable(false);
        setContentPane(pic.getJLabel());
        pack();
        setVisible(true);

    }

    // create the menu bar
    public JMenuBar createMenuBar() {
        JMenu menu;
        JMenuItem menuItem;

        // create the menu bar
        JMenuBar menuBar = new JMenuBar();

        // build the File menu
        menu = new JMenu("File");
        menu.setMnemonic(KeyEvent.VK_F);      // only needed for Alt-f keyboard shortcut
        menuBar.add(menu);
        menuItem = new JMenuItem("Open File...");
        menuItem.addActionListener(new OpenFileListener());
        menu.add(menuItem);
        menuItem = new JMenuItem("Save As...");
        menuItem.addActionListener(new SaveAsListener());
        menu.add(menuItem);

        // build the Process menu
        menu = new JMenu("Process");
        menu.setMnemonic(KeyEvent.VK_P);      // only needed for Alt-p keyboard shortcut
        menuBar.add(menu);
        menuItem = new JMenuItem("Flip Horizontal");
        menuItem.addActionListener(new FlipHorizontalListener());
        menu.add(menuItem);
        menuItem = new JMenuItem("Brighten");
        menuItem.addActionListener(new BrigtenListener());
        menu.add(menuItem);
        menuItem = new JMenuItem("Darken");
        menuItem.addActionListener(new DarkenListener());
        menu.add(menuItem);

        return menuBar;
    }

    // open a file dialog when the user selects "Open" from the menu
    private class OpenFileListener implements ActionListener {
        public void actionPerformed(ActionEvent e) {
            if (chooser.showOpenDialog(ImageProcessor.this) == JFileChooser.APPROVE_OPTION) {
                File file = chooser.getSelectedFile();
                pic = new Picture(file);
                setContentPane(pic.getJLabel());
                pack();
            }
        }
    }

    // open a save dialog when the user selects "Save As" from the menu
    private class SaveAsListener implements ActionListener {
        public void actionPerformed(ActionEvent e) {
            if (chooser.showSaveDialog(ImageProcessor.this) == JFileChooser.APPROVE_OPTION) {
                File file = chooser.getSelectedFile();
                pic.save(file);
            }
        }
    }

    // flip the image horizontally
    private class FlipHorizontalListener implements ActionListener {
        public void actionPerformed(ActionEvent e) {
            int width  = pic.width();
            int height = pic.height();
            for (int y = 0; y < height; y++) {
                for (int x = 0; x < width / 2; x++) {
                    Color c1 = pic.get(x, y);
                    Color c2 = pic.get(width - x - 1, y);
                    pic.set(x, y, c2);
                    pic.set(width - x - 1, y, c1);
                }
            }
            repaint();
        }
    }

    // brigten the image
    private class BrigtenListener implements ActionListener {
        public void actionPerformed(ActionEvent e) {
            for (int y = 0; y < pic.height(); y++) {
                for (int x = 0; x < pic.width(); x++) {
                    Color c = pic.get(x, y);
                    c = c.brighter();
                    pic.set(x, y, c);
                }
            }
            repaint();
        }
    }

    // darken the image
    private class DarkenListener implements ActionListener {
        public void actionPerformed(ActionEvent e) {
            for (int y = 0; y < pic.height(); y++) {
                for (int x = 0; x < pic.width(); x++) {
                    Color c = pic.get(x, y);
                    c = c.darker();
                    pic.set(x, y, c);
                }
            }
            repaint();
        }
    }



    // create one frame object
    public static void main(String[] args) {
        new ImageProcessor();
    }
}