Help with Scrollable Image please...

[Nick Davies]

Hi there, I'm having a bit of a problem

I have a thumbnail of a photo on a form called Photo.java

public class Photo extends javax.swing.JInternalFrame
 
ImageIcon thumbnail = new ImageIcon(file.getPath());
 
displayLabel.setIcon(thumbnail)

When I click the thumbnail it opens a new form (DisplayPhoto.java) where I want to display the photo as it actual size. If the picture is to big, I want to be able to scroll the photo.

I have this so far:

public class DisplayPhoto extends javax.swing.JInternalFrame {
    public DisplayPhoto() 
    {
        initComponents();
        loadPhoto();
    }
 
private void initComponents() 
{
    imagePanel = new javax.swing.JPanel();
    imageScrollPane = new javax.swing.JScrollPane();
    imageLabel = new javax.swing.JLabel();
    getContentPane().setLayout(null);
    setClosable(true);
    setDefaultCloseOperation(javax.swing.WindowConstants.DISPOSE_ON_CLOSE);
    imagePanel.setLayout(new java.awt.BorderLayout());
    imagePanel.setBorder(new javax.swing.border.TitledBorder("Image"));
    imageLabel.setFont(new java.awt.Font("Tahoma", 0, 18));
    imageLabel.setHorizontalAlignment(javax.swing.SwingConstants.CENTER);
    imageLabel.setText("No Image");
    imageScrollPane.setViewportView(imageLabel);
    imagePanel.add(imageScrollPane, java.awt.BorderLayout.CENTER);
    getContentPane().add(imagePanel);
    imagePanel.setBounds(0, 0, 400, 180);
    java.awt.Dimension screenSize = java.awt.Toolkit.getDefaultToolkit().getScreenSize();
    setBounds((screenSize.width-411)/2, (screenSize.height-325)/2, 411, 325);
}
 
private void loadPhoto() 
{
    //Get the image to use.
    ImageIcon myphoto = new ImageIcon("/graphics/user1.gif");
    imageLabel.setIcon(myphoto);
}
}

I want to be able to load the photo from the path of the photo. How do I pass the path from Photo.java to DisplayPhoto.java? Also how will I make the image scrollable?

Any pointers will be greatly appreciated. If anything is not clear please let me know.

Thanks
Nick

[Gregg Bolinger]

You can probably modify this to work for you.

/*
 * This code is based on an example provided by John Vella,
 * a tutorial reader.
 */
 
import javax.swing.*;
import javax.swing.event.MouseInputAdapter;
import java.awt.*;
import java.awt.event.*;
import java.util.*;
 
/* ScrollDemo2.java is a 1.4 application that requires no other files. */
public class ScrollDemo2 extends JPanel
                         implements MouseListener {
    private Dimension area; //indicates area taken up by graphics
    private Vector circles; //coordinates used to draw graphics
    private JPanel drawingPane;
 
    private final Color colors[] = {
        Color.red, Color.blue, Color.green, Color.orange,
        Color.cyan, Color.magenta, Color.darkGray, Color.yellow};
    private final int color_n = colors.length;
 
    public ScrollDemo2() {
        super(new BorderLayout());
 
        area = new Dimension(0,0);
        circles = new Vector();
 
        //Set up the instructions.
        JLabel instructionsLeft = new JLabel(
                        "Click left mouse button to place a circle.");
        JLabel instructionsRight = new JLabel(
                        "Click right mouse button to clear drawing area.");
        JPanel instructionPanel = new JPanel(new GridLayout(0,1));
        instructionPanel.add(instructionsLeft);
        instructionPanel.add(instructionsRight);
 
        //Set up the drawing area.
        drawingPane = new DrawingPane();
        drawingPane.setBackground(Color.white);
        drawingPane.addMouseListener(this);
 
        //Put the drawing area in a scroll pane.
        JScrollPane scroller = new JScrollPane(drawingPane);
        scroller.setPreferredSize(new Dimension(200,200));
 
        //Lay out this demo.
        add(instructionPanel, BorderLayout.PAGE_START);
        add(scroller, BorderLayout.CENTER);
    }
 
    /** The component inside the scroll pane. */
    public class DrawingPane extends JPanel {
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
 
            Rectangle rect;
            for (int i = 0; i < circles.size(); i++) {
                rect = (Rectangle)circles.elementAt(i);
                g.setColor(colors[(i % color_n)]);
                g.fillOval(rect.x, rect.y, rect.width, rect.height);
            }
        }
    }
 
    //Handle mouse events.
    public void mouseReleased(MouseEvent e) {
        final int W = 100;
        final int H = 100;
        boolean changed = false;
        if (SwingUtilities.isRightMouseButton(e)) {
            //This will clear the graphic objects.
            circles.removeAllElements();
            area.width=0;
            area.height=0;
            changed = true;
        } else {
            int x = e.getX() - W/2;
            int y = e.getY() - H/2;
            if (x < 0) x = 0;
            if (y < 0) y = 0;
            Rectangle rect = new Rectangle(x, y, W, H);
            circles.addElement(rect);
            drawingPane.scrollRectToVisible(rect);
 
            int this_width = (x + W + 2);
            if (this_width > area.width) {
                area.width = this_width; changed=true;
            }
 
            int this_height = (y + H + 2);
            if (this_height > area.height) {
                area.height = this_height; changed=true;
            }
        }
        if (changed) {
            //Update client's preferred size because
            //the area taken up by the graphics has
            //gotten larger or smaller (if cleared).
            drawingPane.setPreferredSize(area);
 
            //Let the scroll pane know to update itself
            //and its scrollbars.
            drawingPane.revalidate();
        }
        drawingPane.repaint();
    }
    public void mouseClicked(MouseEvent e){}
    public void mouseEntered(MouseEvent e){}
    public void mouseExited(MouseEvent e){}
    public void mousePressed(MouseEvent e){}
 
    /**
     * Create the GUI and show it.  For thread safety,
     * this method should be invoked from the
     * event-dispatching thread.
     */
    private static void createAndShowGUI() {
        //Make sure we have nice window decorations.
        JFrame.setDefaultLookAndFeelDecorated(true);
 
        //Create and set up the window.
        JFrame frame = new JFrame("ScrollDemo2");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 
        //Create and set up the content pane.
        JComponent newContentPane = new ScrollDemo2();
        newContentPane.setOpaque(true); //content panes must be opaque
        frame.setContentPane(newContentPane);
 
        //Display the window.
        frame.pack();
        frame.setVisible(true);
    }
 
    public static void main(String[] args) {
        //Schedule a job for the event-dispatching thread:
        //creating and showing this application's GUI.
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGUI();
            }
        });
    }
}

[Stuart Gray]

Could you also just use an ImageIcon and put that in a JScrollPane? Or am I missing something?

[Craig Wood]

import java.awt.*;
import java.awt.event.*;
import java.awt.image.*;
import javax.swing.*;
 
public class ImageFrames
{
    JDesktopPane desktop;
 
    public ImageFrames()
    {
        Image[] images = loadImages();
        JInternalFrame thumbFrame = getThumbFrame(images);
        desktop = new JDesktopPane();
        desktop.add(thumbFrame);
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.getContentPane().add(desktop);
        f.setSize(400,400);
        f.setLocation(200,200);
        f.setVisible(true);
    }
 
    private JInternalFrame getThumbFrame(Image[] images)
    {
        ThumbListener listener = new ThumbListener();
        JPanel panel = new JPanel(new GridBagLayout());
        GridBagConstraints gbc = new GridBagConstraints();
        gbc.weighty = 1.0;
        gbc.weightx = 1.0;
        for(int j = 0; j < images.length; j++)
        {
            Thumbnail thumbnail = new Thumbnail(images[j]);
            thumbnail.addMouseListener(listener);
            if(j % 2 == 0)
                gbc.gridwidth = GridBagConstraints.RELATIVE;
            else
                gbc.gridwidth = GridBagConstraints.REMAINDER;
            panel.add(thumbnail, gbc);
        }
        JInternalFrame iframe = new JInternalFrame("photo selection", true,
                                                    true, true, true);
        iframe.getContentPane().add(panel);
        iframe.setSize(300,300);
        iframe.setLocation(40,40);
        iframe.setVisible(true);
        return iframe;
    }
 
    private Image[] loadImages()
    {
        String[] fileNames = {
            "cougar.jpg", "mtngoat.jpg", "sawwhetowl.jpg", "owls.jpg" };
        Image[] images = new Image[fileNames.length];
        for(int j = 0; j < images.length; j++)
            images[j] = new ImageIcon("images/" + fileNames[j]).getImage();
        return images;
    }
 
    private class ThumbListener extends MouseAdapter
    {
        public void mousePressed(MouseEvent e)
        {
            Thumbnail thumbnail = (Thumbnail)e.getSource();
            Image image = thumbnail.image;
            desktop.add(new DisplayPhoto(image));
        }
    }
 
    public static void main(String[] args)
    {
        new ImageFrames();
    }
}
 
class DisplayPhoto extends JInternalFrame
{
    public DisplayPhoto(Image image) 
    {
        initComponents(image);
    }
 
    private void initComponents(Image image) 
    {
        JLabel imageLabel = new JLabel(new ImageIcon(image));
        setClosable(true);
        setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);
        imageLabel.setBorder(BorderFactory.createTitledBorder("Image"));
        imageLabel.setFont(new Font("Tahoma", 0, 18));
        imageLabel.setHorizontalAlignment(SwingConstants.CENTER);
        imageLabel.setText("No Image");
        getContentPane().add(new JScrollPane(imageLabel));
        setSize(350,350);
        setLocation(50,50);
        setVisible(true);
    }
} 
 
class Thumbnail extends JPanel
{
    Image image, scaledImage;
    MediaTracker tracker;
    final int
        WIDTH  = 50,
        HEIGHT = 75;
 
    public Thumbnail(Image image)
    {
        this.image = image;
        tracker = new MediaTracker(this);
        scaleImage(image);
    }
 
    protected void paintComponent(Graphics g)
    {
        super.paintComponent(g);
        Graphics2D g2 = (Graphics2D)g;
        g2.setRenderingHint(RenderingHints.KEY_INTERPOLATION,
                            RenderingHints.VALUE_INTERPOLATION_BICUBIC);
        int w = scaledImage.getWidth(this);
        int h = scaledImage.getHeight(this);
        int x = (WIDTH - w)/2;
        int y = (HEIGHT - h)/2;
        g2.drawImage(scaledImage, x, y, this);
    }
 
    public Dimension getPreferredSize()
    {
        return new Dimension(WIDTH, HEIGHT);
    }
 
    private void scaleImage(Image image)
    {
        double imageWidth = image.getWidth(this);
        double imageHeight = image.getHeight(this);
        double xScale = WIDTH / imageWidth;
        double yScale = HEIGHT / imageHeight;
        // scale to fit
        //double scale = Math.min(xScale, yScale);
        // scale to fill
        double scale = Math.max(xScale, yScale);
        int scaledWidth  = (int)(imageWidth * scale);
        int scaledHeight = (int)(imageHeight * scale);
        scaledImage = image.getScaledInstance(scaledWidth, scaledHeight,
                                              Image.SCALE_AREA_AVERAGING);
        // image returned from getScaledImage may load asynchronously
        tracker.addImage(scaledImage, 0);
        try
        {
            tracker.waitForID(0);
        }
        catch(InterruptedException ie)
        {
            System.err.println("interrupt: " + ie.getMessage());
        }
    }
}