Tugas PBO B: Image Viewer

1. Class Window

2. Source Code
ImageViewer

import java.awt.*;
import java.awt.event.*;
import java.awt.image.*;
import javax.swing.*;
import java.io.File;

public class ImageViewer
{
    private static final String VERSION = "Version 1.0";
    private static JFileChooser fileChooser = new JFileChooser(System.getProperty("user.dir"));
    
    private JFrame frame;
    private ImagePanel imagePanel;
    private JLabel filenameLabel;
    private JLabel statusLabel;
    private OFImage currentImage;
    
    public ImageViewer()
    {
        currentImage = null;
        makeFrame();
    }
    
    private void openFile()
    {
        int returnVal = fileChooser.showOpenDialog(frame);
        
        if (returnVal != JFileChooser.APPROVE_OPTION)
        {
            return;
        }
        
        File selectedFile = fileChooser.getSelectedFile();
        currentImage = ImageFileManager.loadImage(selectedFile);
        
        if (currentImage == null)
        {
            JOptionPane.showMessageDialog(frame, "The file was not in a recognized image file format", "Image Load Error", JOptionPane.ERROR_MESSAGE);
            return;
        }
        
        imagePanel.setImage(currentImage);
        showFilename(selectedFile.getPath());
        showStatus("File loaded.");
        frame.pack();
    }
    
    private void close()
    {
        currentImage = null;
        imagePanel.clearImage();
        showFilename(null);
    }
    
    private void quit()
    {
        System.exit(0);
    }
    
    private void makeDarker()
    {
        if (currentImage != null)
        {
            currentImage.darker();
            frame.repaint();
            showStatus("Applied: darker");
        }
        else
        {
            showStatus("No image loaded");
        }
    }
    
    private void makeLighter()
    {
        if (currentImage != null)
        {
            currentImage.lighter();
            frame.repaint();
            showStatus("Applied: lighter");
        }
        else
        {
            showStatus("No image loaded");
        }
    }
    
    private void threshold()
    {
        if (currentImage != null)
        {
            currentImage.threshold();
            frame.repaint();
            showStatus("Applied: threshold");
        }
        else
        {
            showStatus("No image loaded");
        }        
    }
    
    private void showAbout()
    {
        JOptionPane.showMessageDialog(frame, "Image Viewer\n" + VERSION, "About Image Viewer", JOptionPane.INFORMATION_MESSAGE);
    }
    
    private void showFilename(String filename)
    {
        if (filename == null)
        {
            filenameLabel.setText("No file displayed");
        }
        else
        {
            filenameLabel.setText("File: " + filename);
        }
    }
    
    private void showStatus(String text)
    {
        statusLabel.setText(text);
    }
    
    private void makeFrame()
    {
        frame = new JFrame("Image Viewer");
        makeMenuBar(frame);
        
        Container contentPane = frame.getContentPane();
        contentPane.setLayout(new BorderLayout(6, 6));
        filenameLabel = new JLabel();
        contentPane.add(filenameLabel, BorderLayout.NORTH);
        imagePanel = new ImagePanel();
        contentPane.add(imagePanel, BorderLayout.CENTER); 
        statusLabel = new JLabel(VERSION);
        contentPane.add(statusLabel, BorderLayout.SOUTH);
        showFilename(null);
        frame.pack();
        Dimension d = Toolkit.getDefaultToolkit().getScreenSize();
        frame.setLocation(d.width/2 - frame.getWidth()/2, d.height/2 - frame.getHeight()/2);
        frame.setVisible(true);
    }
    
    private void makeMenuBar(JFrame frame)   
    {   
        final int SHORTCUT_MASK = Toolkit.getDefaultToolkit().getMenuShortcutKeyMask();
        JMenuBar menubar = new JMenuBar();
        frame.setJMenuBar(menubar);
        JMenu menu;
        JMenuItem item;
        menu = new JMenu("File");
        menubar.add(menu);
        item = new JMenuItem("Open");
        item.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_O, SHORTCUT_MASK));
        item.addActionListener(new ActionListener()
            {
                public void actionPerformed(ActionEvent e)
                {
                    openFile();
                }
            });
        menu.add(item);
      
        item = new JMenuItem("Close"); 
        item.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_W, SHORTCUT_MASK));
        item.addActionListener(new ActionListener()
            {   
                public void actionPerformed(ActionEvent e)
                {
                    close();
                }
            });
        menu.add(item);
        menu.addSeparator();
      
        item = new JMenuItem("Quit");
        item.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_Q, SHORTCUT_MASK));
        item.addActionListener(new ActionListener()
            {
                public void actionPerformed(ActionEvent e)
                {
                    quit();
                }   
            });   
        menu.add(item);   
   
        menu = new JMenu("Filter");
        menubar.add(menu);
        item = new JMenuItem("Darker");
        item.addActionListener(new ActionListener()
            {
                public void actionPerformed(ActionEvent e)
                {
                    makeDarker();
                }
            });
        menu.add(item);
      
        item = new JMenuItem("Lighter");
        item.addActionListener(new ActionListener()
            {   
                public void actionPerformed(ActionEvent e)
                {
                    makeLighter();
                }
            });   
        menu.add(item);
      
        item = new JMenuItem("Threshold");
        item.addActionListener(new ActionListener()
            {
                public void actionPerformed(ActionEvent e)
                {
                    threshold();
                }
            });   
        menu.add(item);

        menu = new JMenu("Help");
        menubar.add(menu);
        item = new JMenuItem("About ImageViewer...");
        item.addActionListener(new ActionListener()
            {   
                public void actionPerformed(ActionEvent e)
                {
                    showAbout();
                }
            });
        menu.add(item);
    }
}

ImageFileManager

import java.awt.image.*;
import javax.imageio.*;
import java.io.*;

public class ImageFileManager
{
    private static final String IMAGE_FORMAT = "jpg";
    
    public static OFImage loadImage(File imageFile)
    {
        try
        {
            BufferedImage image = ImageIO.read(imageFile); 
            if (image == null || (image.getWidth(null) < 0))
            {
                return null;
            }
            return new OFImage(image);
        }
        catch (IOException exc)
        {
            return null;
        }
    }
    
    public static void saveImage(OFImage image, File file)
    {   
        try   
        {
            ImageIO.write(image, IMAGE_FORMAT, file);
        }
        catch (IOException exc)
        {
            return;
        }
    }   
}

ImagePanel

import java.awt.*;
import javax.swing.*;
import java.awt.image.*;

public class ImagePanel extends JComponent
{
    private int width;
    private int height;
    private OFImage panelImage;
    
    public ImagePanel()
    {
        width = 30;
        height = 30;
        panelImage = null;
    }
    
    public void setImage(OFImage image)
    {
        if (image != null)
        {
            width = image.getWidth();
            height = image.getHeight();
            panelImage = image;
            repaint();
        }
    }
    
    public void clearImage()   
    {   
        Graphics imageGraphics = panelImage.getGraphics();
        imageGraphics.setColor(Color.LIGHT_GRAY);
        imageGraphics.fillRect(0, 0, width, height);
        repaint();
    }
    
    public Dimension getPreferredSize()
    {
        return new Dimension(width, height);
    }
    
    public void paintComponent(Graphics g)
    {   
        Dimension size = getSize();
        g.clearRect(0, 0, size.width, size.height);
        if(panelImage != null)
        {
            g.drawImage(panelImage, 0, 0, null);
        }
    }   
}

OFImage

import java.awt.*;
import java.awt.image.*;
import javax.swing.*;

public class OFImage extends BufferedImage
{
    public OFImage(BufferedImage image)
    {
        super(image.getColorModel(), image.copyData(null), image.isAlphaPremultiplied(), null);
    }
    
    public OFImage(int width, int height)
    {
        super(width, height, TYPE_INT_RGB);
    }
    
    public void setPixel(int x, int y, Color col)
    {
        int pixel = col.getRGB();
        setRGB(x, y, pixel);
    }
    
    public Color getPixel(int x, int y)
    {
        int pixel = getRGB(x, y);
        return new Color(pixel);
    }
    
    public void darker()
    {
        int height = getHeight();
        int width = getWidth();
        
        for (int y = 0; y < height; y++)
        {
            for (int x = 0; x < width; x++)
            {
                setPixel(x, y, getPixel(x, y).darker());
            }
        }
    }
    
    public void lighter()
    {
        int height = getHeight();
        int width = getWidth();
        
        for (int y = 0; y < height; y++)
        {
            for (int x = 0; x < width; x++)
            {
                setPixel(x, y, getPixel(x, y).brighter());
            }
        }
    }
    
    public void threshold()
    {
        int height = getHeight();
        int width = getWidth();
        
        for (int y = 0; y < height; y++)
        {
            for (int x = 0; x < width; x++)
            {
                Color pixel = getPixel(x, y);
                int brightness = (pixel.getRed() + pixel.getBlue() + pixel.getGreen()) / 3;
                if (brightness <= 85)
                {
                    setPixel(x, y, Color.BLACK);
                }
                else if (brightness <= 170)
                {
                    setPixel(x, y, Color.GRAY);
                }
                else
                {
                    setPixel(x, y, Color.WHITE);
                }
            }
        }
    }
}

3. Output
Untuk menjalankan program Image Viewer ini, maka dibuatlah sebuah instance dari kelas ImageViewer