Display an image for a set time

[Chris Ramsey]

I have an application that should load an image to be set as an icon for a JLabel from JPEG files. The file names are numbers ie. (0.jpg, 1.jpg, ...) so that i can choose the files with a loop and use the loop index as the image name to be retrieved.
Depending on some user action the picture should be set visible for about 5 seconds, set invisible, unload the image, retrieve the next image and then depending on the user action, show it again for another couple of seconds. The way I am doing it it takes the image a long time to be shown. I thought by loading it before I would actually need it that it would speed things up, but thats not what happens. It takes a long time for the image to visible. I have a resource manager class responsible for creating the images from the jpegs. They also have to be resized so that may be why it is taking so long. Here's the resource class makeImage method.

 
// ResourceManager creates and gets the image files
public ImageIcon makeImage(final String imageName)
{
    ImageIcon icon = null;
    try
    {
URL url = cl.getResource("com/images/" + (imageName));
Image image = ImageIO.read(url);
icon = new ImageIcon(image.getScaledInstance(200,200,Image.SCALE_SMOOTH));
    }
    catch (MalformedURLException e)
    {
System.out.println("bad URL: " + e.getMessage());
    }
    catch (IOException e)
    {
System.out.println("IO error: " + e.getMessage());
    }
 
return icon;
}

The load and show picture methods are in another class that defines a picture panel

 
// picture panel
public class PicturePanel extends JPanel
{
    private static int imageIndex = 0;
    private JLabel picture;
    private JLabel correctLabel;
    private JPanel innerPanel;
    private static ResourceManager rm = ResourceManager.getInstance();
 
    // creates picture panel
    public PicturePanel()
    {
// get class loader
cl = this.getClass().getClassLoader();
 
setBorder(BorderFactory.createTitledBorder("Answer"));
 
// layout components
FormDebugPanel debug = new FormDebugPanel(true, false);
FormLayout layout = new FormLayout("pref:g", "pref:n");
CellConstraints cc = new CellConstraints();
DefaultFormBuilder builder = new DefaultFormBuilder(this, layout);
 
// inner panel
innerPanel = new JPanel();
 
// picture label
picture = new JLabel();
picture.setText("Correct!");
picture.setVisible(false);
 
// add picture label to inner panel
innerPanel.add(picture);
 
// add innerPanel to picture panel
builder.add(innerPanel, cc.xy(1, 1, "center, center"));
    }
 
    // show a picture on the picture panel
    protected void showPicture()
    {
System.out.println("in show picture:");
javax.swing.SwingUtilities.invokeLater(new Runnable()
{
    public void run()
    {
picture.setVisible(true);
        imageIndex++;
    }
});
    }
 
    // show a picture on the picture panel
    protected void loadPicture()
    {
picture.setIcon(null);
 
javax.swing.SwingUtilities.invokeLater(new Runnable()
{
    public void run()
    {
picture.setIcon(rm.makeImage((String.valueOf(imageIndex)+".jpg")));
    }
});
    }
  

So if the user action is appropriate then the picture panel should be displayed and another one loaded up. I thought using the SwingUtlities would solve any thread issues. Is there some additional thread sequencing that I should do in order for the action to be faster? Thanks for the suggestions.

[ June 23, 2004: Message edited by: Chris Ramsey ]
[ June 23, 2004: Message edited by: Chris Ramsey ]

[Craig Wood]

This works fast on my computer. If it's still too slow for you I suggest you explore using the createCompatibleImage method in the GraphicsConfiguration class. I've read it can make a difference in rendering time.

import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import java.awt.image.BufferedImage;
import java.io.*;
import java.net.*;
import javax.imageio.ImageIO;
import javax.swing.*;
import javax.swing.Timer;
 
public class ImageTest
{
    public static void main(String[] args)
    {
        ImageDisplay display = new ImageDisplay();
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.getContentPane().add(display.getSelectionPanel(), "West");
        f.getContentPane().add(display);
        f.setSize(400,400);
        f.setLocation(200,200);
        f.setVisible(true);
    }
}
 
class ImageDisplay extends JPanel
{
    ImageLoader loader;
    ImageIcon[] icons;
    JLabel label;
    JLabel[] labels;
 
    public ImageDisplay()
    {
        loader = new ImageLoader();
        Image[] images = loader.loadImages();
        createIcons(images);
        setBackground(new Color(240,200,240));
        setLayout(new GridBagLayout());
        GridBagConstraints gbc = new GridBagConstraints();
        label = new JLabel(icons[0]);
        label.setPreferredSize(new Dimension(200,200));
        add(label, gbc);
    }
 
    private void createIcons(Image[] images)
    {
        icons = new ImageIcon[images.length];
        for(int j = 0; j < icons.length; j++)
            icons[j] = new ImageIcon(images[j]);
    }
 
    public JPanel getSelectionPanel()
    {
        labels = new JLabel[4];
        ImageScheduler scheduler = new ImageScheduler(this);
        String[] names = loader.getFileNames();
        JPanel panel = new JPanel(new GridBagLayout());
        GridBagConstraints gbc = new GridBagConstraints();
        gbc.insets = new Insets(0,2,0,2);
        gbc.weighty = 1.0;
        gbc.weightx = 1.0;
        gbc.fill = gbc.HORIZONTAL;
        gbc.gridwidth = gbc.REMAINDER;
        for(int j = 0; j < labels.length; j++)
        {
            labels[j] = new JLabel(names[j], JLabel.CENTER);
            labels[j].addMouseListener(scheduler);
            panel.add(labels[j], gbc);
        }
        return panel;
    }
 
    public JLabel getLabel()
    {
        return label;
    }
 
    public JLabel[] getSelectionLabels()
    {
        return labels;
    }
 
    public ImageIcon[] getIcons()
    {
        return icons;
    }
}
 
/**
 * Loads images and scales them to fit 200 x 200 size.
 */
class ImageLoader
{
    String[] fileNames;
    final static int
        W = 200,
        H = 200;
 
    public Image[] loadImages()
    {
        fileNames = new String[] {
            "cougar", "redfox", "greathornedowl", "barnowl"
        };
        String prefix = "images/";
        String ext = ".jpg";
        BufferedImage[] images = new BufferedImage[fileNames.length];
        for(int j = 0; j < images.length; j++)
            try
            {
                URL url = getClass().getResource(prefix + fileNames[j] + ext);
                images[j] = scaleImage(ImageIO.read(url));
            }
            catch(MalformedURLException mue)
            {
                System.out.println("Bad URL: " + mue.getMessage());
            }
            catch(IOException ioe)
            {
                System.out.println("Unable to read: " + ioe.getMessage());
            }
        return images;
    }
 
    private BufferedImage scaleImage(BufferedImage biIn)
    {
        BufferedImage biOut = new BufferedImage(W, H, BufferedImage.TYPE_INT_RGB);
        Graphics2D g2 = biOut.createGraphics();
        double w = biIn.getWidth();
        double h = biIn.getHeight();
        double xScale = W / w;
        double yScale = H / h;
        double scale = Math.min(xScale, yScale);
        double x = (W - w * scale)/2;
        double y = (H - h * scale)/2;
        AffineTransform at = AffineTransform.getTranslateInstance(x, y);
        at.scale(scale, scale);
        g2.drawRenderedImage(biIn, at);
        g2.dispose();
        return biOut;
    }
 
    public String[] getFileNames()
    {
        return fileNames;
    }
}
 
/**
 * Shows image for 5 seconds in center section of gui
 * when image name is moused-over in west section.
 */
class ImageScheduler extends MouseAdapter
{
    ImageDisplay imageDisplay;
    Timer timer;
 
    public ImageScheduler(ImageDisplay id)
    {
        imageDisplay = id;
        timer = new Timer(5000, new ActionListener()
        {
            public void actionPerformed(ActionEvent e)
            {
                imageDisplay.getLabel().setIcon(null);
            }
        });
        timer.setRepeats(false);
    }
 
    public void mouseEntered(MouseEvent e)
    {
        timer.stop();
        JLabel label = (JLabel)e.getSource();
        JLabel[] labels = imageDisplay.getSelectionLabels();
        int index = 0;
        for(int j = 0; j < labels.length; j++)
            if(label == labels[j])
                index = j;
 
        ImageIcon icon = imageDisplay.getIcons()[index];
        imageDisplay.getLabel().setIcon(icon);
    }
 
    public void mouseExited(MouseEvent e)
    {
        timer.start();
    }
}

[Chris Ramsey]

Thanks Craig! Will try this approach.