CreateThumbnail.java

package com.usemodj.struts;

import java.awt.Graphics;
import java.awt.Image;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;

import javax.imageio.ImageIO;
import javax.swing.ImageIcon;

public class CreateThumbnail {
    public static final int VERTICAL = 0;
    public static final int HORIZONTAL = 1;

    public static final String IMAGE_JPEG = "jpeg";
    public static final String IMAGE_JPG = "jpg";
    public static final String IMAGE_PNG = "png";

    private ImageIcon image;
    private ImageIcon thumb;

    public CreateThumbnail(Image image)
    {
        this.image = new ImageIcon(image); 
    }
    
    public CreateThumbnail(String fileName)
    {
        image = new ImageIcon(fileName);
    }
    
    public Image getThumbnail(int size, int dir)
    {
        if (dir == HORIZONTAL)
        {
            thumb = new ImageIcon(
                image.getImage().getScaledInstance(
                    size, -1, Image.SCALE_SMOOTH)
            );
        }
        else
        {
            thumb = new ImageIcon(
                image.getImage().getScaledInstance(
                    -1, size, Image.SCALE_SMOOTH)
            );
        }
        return thumb.getImage();
    }
    
    public Image getThumbnail(int size, int dir, int scale)
    {
        if (dir == HORIZONTAL)
        {
            thumb = new ImageIcon(
                image.getImage().getScaledInstance(size, -1, scale)
            );
        }
        else
        {
            thumb = new ImageIcon(
                image.getImage().getScaledInstance(-1, size, scale)
            );
        }
        return thumb.getImage();
    }
    
    public void saveThumbnail(File file, String imageType)
    {
        if (thumb != null)
        {
            BufferedImage bi = new BufferedImage(
                thumb.getIconWidth(), 
                thumb.getIconHeight(), 
                BufferedImage.TYPE_INT_RGB
            );
            Graphics g = bi.getGraphics();
            g.drawImage(thumb.getImage(), 0, 0, null);
            try
            {
                ImageIO.write(bi, imageType, file);
            }
            catch (IOException ioe)
            {
                System.out.println("Error occured saving thumbnail");
            }
        }
        else
        {
            System.out.println("Thumbnail has not yet been created");
        }
    }
    
    public static void main(String [] args)
    {
        CreateThumbnail ct = new CreateThumbnail("image.jpg");
        ct.getThumbnail(100, CreateThumbnail.HORIZONTAL);
        ct.saveThumbnail(new File("thumb.jpg"), CreateThumbnail.IMAGE_JPEG);
    }

}