ImagePreview.java

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package feuille.karaoke.lib;

import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Image;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.io.File;
import javax.swing.ImageIcon;
import javax.swing.JComponent;
import javax.swing.JFileChooser;

// Code from ImagePreview.java (FileChooserDemo2.java - Sun Microsystems)
/** <p>This class is a component to view thumbnails.<br />
 * Cette classe est un composant pour lire des petites images.</p> */
public class ImagePreview extends JComponent implements PropertyChangeListener {
    ImageIcon thumbnail = null;
    File file = null;

    /** <p>Create a new ImagePreview.<br />Crée un nouveau ImagePreview.</p>
     * @param fc The parent JFileChooser. */
    @SuppressWarnings("LeakingThisInConstructor")
    public ImagePreview(JFileChooser fc) {
        setPreferredSize(new Dimension(100, 50));
        fc.addPropertyChangeListener(this);
    }

    /** <p>Load an image.<br />Charge une image.</p> */
    public void loadImage() {
        if (file == null) {
            thumbnail = null;
            return;
        }

        //Don't use createImageIcon (which is a wrapper for getResource)
        //because the image we're trying to load is probably not one
        //of this program's own resources.
        ImageIcon tmpIcon = new ImageIcon(file.getPath());
        if (tmpIcon != null) {
            if (tmpIcon.getIconWidth() > 90) {
                thumbnail = new ImageIcon(tmpIcon.getImage()
                        .getScaledInstance(90, -1,Image.SCALE_DEFAULT));
            } else { //no need to miniaturize
                thumbnail = tmpIcon;
            }
        }
    }

    /** <p>Update the thumbnail if necessary.<br />
     * Met à jour la petite image si nécessaire.</p> */
    @Override
    public void propertyChange(PropertyChangeEvent e) {
        boolean update = false;
        String prop = e.getPropertyName();

        //If the directory changed, don't show an image.
        if (JFileChooser.DIRECTORY_CHANGED_PROPERTY.equals(prop)) {
            file = null;
            update = true;

        //If a file became selected, find out which one.
        } else if (JFileChooser.SELECTED_FILE_CHANGED_PROPERTY.equals(prop)) {
            file = (File) e.getNewValue();
            update = true;
        }

        //Update the preview accordingly.
        if (update) {
            thumbnail = null;
            if (isShowing()) {
                loadImage();
                repaint();
            }
        }
    }

    /** <p>Paint the thumbnail.<br />Peint la petite image.</p> */
    @Override
    protected void paintComponent(Graphics g) {
        if (thumbnail == null) {
            loadImage();
        }
        if (thumbnail != null) {
            int x = getWidth()/2 - thumbnail.getIconWidth()/2;
            int y = getHeight()/2 - thumbnail.getIconHeight()/2;

            if (y < 0) {
                y = 0;
            }

            if (x < 5) {
                x = 5;
            }
            thumbnail.paintIcon(this, g, x, y);
        }
    }

}