ImagePreview.java

/*
 * @(#)TestFileChooserAccessory.java  1.0  December 10, 2005
 *
 * This code is copyright by Sun Microsystems.
 * It has been copied from
 * http://java.sun.com/docs/books/tutorial/uiswing/components/example-1dot4/ImagePreview.java
 */

package test;

import javax.swing.*;
import java.beans.*;
import java.awt.*;
import java.io.File;

/**
 * ImagePreview.java is a 1.4 example used by FileChooserDemo2.java.
 *
 * @author  Werner Randelshofer
 * @version 1.0 December 10, 2005 Created.
 */
public class ImagePreview extends JComponent implements PropertyChangeListener {
    ImageIcon thumbnail = null;
    File file = null;
    
    
    public ImagePreview(JFileChooser fc) {
        setPreferredSize(new Dimension(100, 50));
        fc.addPropertyChangeListener(this);
    }
    
    
    
    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;
            }
        }
    }
    
    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();
            }
        }
    }
    
    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);
        }
    }

    /** This method is called from within the constructor to
     * initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is
     * always regenerated by the Form Editor.
     */
    private void initComponents() {//GEN-BEGIN:initComponents

        setLayout(new java.awt.BorderLayout());

    }//GEN-END:initComponents
    
    
    
    
    // Variables declaration - do not modify//GEN-BEGIN:variables
    // End of variables declaration//GEN-END:variables
    
}