Image Resizing Woes

[Luke Shannon]

Hello All;

Got image resizing working ok in my application. It creates thumbnails for full sized pics that have been uploaded.

The only problem is the thumbnail ends up looking a little pixelated.

I have tried Image.SCALE_AREA_AVERAGING and Image.SCALE_SMOOTH. They both look about the same. Can anyone see anything in my code that might be causing this? Maybe a tip I can try to smooth things out?

Thanks,

Luke

if ((imageThumb.getHeight() >= 76) || (imageThumb.getWidth() >= 76)) {
myLogger.debug(ImageUploader.class.getName()
+ "Need to scale for thumb");
if (imageThumb.getHeight() > imageThumb.getWidth())
resizeWidth = false;
Image scaledImage = null;
if (resizeWidth) {
scaledImage = imageThumb.getScaledInstance(75, -1,
Image.SCALE_SMOOTH);
} else {
scaledImage = imageThumb.getScaledInstance(-1, 75,
Image.SCALE_SMOOTH);
}
myLogger.debug(ImageUploader.class.getName() + "Dimension are: w="
+ scaledImage.getWidth(null) + " h= "
+ scaledImage.getHeight(null) + "Had to scale the width: "
+ resizeWidth);
BufferedImage scaledImageBuffer = null;
try {
GraphicsEnvironment ge = GraphicsEnvironment
.getLocalGraphicsEnvironment();
GraphicsDevice gs = ge.getDefaultScreenDevice();
GraphicsConfiguration gc = gs.getDefaultConfiguration();
scaledImageBuffer = gc.createCompatibleImage(scaledImage
.getWidth(null), scaledImage.getHeight(null),
BufferedImage.TYPE_INT_RGB);
} catch (HeadlessException e) {
// The system does not have a screen
}
if (scaledImageBuffer == null) {
int type = BufferedImage.TYPE_INT_RGB;
scaledImageBuffer = new BufferedImage(scaledImage
.getWidth(null), scaledImage.getHeight(null), type);
}
Graphics g = scaledImageBuffer.createGraphics();
g.drawImage(imageThumb, 0, 0, scaledImage.getWidth(null),
scaledImage.getHeight(null), null);
g.dispose();
myLogger.debug(ImageUploader.class.getName()
+ " Graphics disposed.");
ImageIO.write(scaledImageBuffer, "jpeg", thumb);
myLogger.debug(ImageUploader.class.getName()
+ " Image written to file.");
}

[Craig Wood]

import java.awt.*;
import java.awt.event.*;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.io.*;
import java.net.*;
import javax.imageio.ImageIO;
import javax.swing.*;
 
public class ImageSizing
{
    ImageIcon[] icons;
    final int
        W = 76,
        H = 76;
 
    public ImageSizing()
    {
        BufferedImage[] images = getImages();
        makeIcons(images);
    }
 
    private BufferedImage[] getImages()
    {
        String[] fileNames = { "greathornedowl.jpg", "redfox.jpg" };
        BufferedImage[] images = new BufferedImage[fileNames.length];
        for(int j = 0; j < images.length; j++)
            try
            {
                URL url = getClass().getResource("images/" + fileNames[j]);
                images[j] = ImageIO.read(url);
            }
            catch(MalformedURLException mue)
            {
                System.err.println("malformed url for image: " + mue.getMessage());
            }
            catch(IOException ioe)
            {
                System.err.println("unable to read image file: " + ioe.getMessage());
            }
        return images;
    }
 
    private void makeIcons(BufferedImage[] images)
    {
        icons = new ImageIcon[2 * images.length];
        for(int j = 0, k = 0; j < images.length; j++, k+=2)
        {
            icons[k]   = new ImageIcon(scaleToFill(images[j]));
            icons[k+1] = new ImageIcon(scaleToFit(images[j]));
        }
    }
 
    private BufferedImage scaleToFill(BufferedImage source)
    {
        BufferedImage scaled = new BufferedImage(W, H, source.getType());
        Graphics2D g2 = scaled.createGraphics();
        g2.setRenderingHint(RenderingHints.KEY_INTERPOLATION,
                            RenderingHints.VALUE_INTERPOLATION_BICUBIC);
        double width = source.getWidth();
        double height = source.getHeight();
        double xScale = W / width;
        double yScale = H / height;
        double scale = Math.max(xScale, yScale);
        double x = (W - scale*width)/2;
        double y = (H - scale*height)/2;
        AffineTransform at = AffineTransform.getScaleInstance(scale, scale);
        g2.translate(x, y);
        g2.drawRenderedImage(source, at);
        g2.dispose();
        return scaled;
    }
 
    private BufferedImage scaleToFit(BufferedImage source)
    {
        BufferedImage scaled = new BufferedImage(W, H, source.getType());
        Graphics2D g2 = scaled.createGraphics();
        g2.setRenderingHint(RenderingHints.KEY_INTERPOLATION,
                            RenderingHints.VALUE_INTERPOLATION_BICUBIC);
        g2.setPaint(UIManager.getColor("Panel.background"));
        g2.fillRect(0,0,W,H);
        double width = source.getWidth();
        double height = source.getHeight();
        double xScale = W / width;
        double yScale = H / height;
        double scale = Math.min(xScale, yScale);
        double x = (W - scale*width)/2;
        double y = (H - scale*height)/2;
        AffineTransform at = AffineTransform.getScaleInstance(scale, scale);
        g2.translate(x, y);
        g2.drawRenderedImage(source, at);
        g2.dispose();
        return scaled;
    }
 
    private JPanel getPanel()
    {
        JPanel panel = new JPanel(new GridBagLayout());
        GridBagConstraints gbc = new GridBagConstraints();
        gbc.weighty = 1.0;
        gbc.weightx = 1.0;
        for(int j = 0; j < icons.length; j++)
        {
            JLabel label = new JLabel(icons[j]);
            if(j % 2 == 0)
                gbc.gridwidth = gbc.RELATIVE;
            else
                gbc.gridwidth = gbc.REMAINDER;
            panel.add(label, gbc);
        }
        return panel;
    }
 
    public static void main(String[] args)
    {
        ImageSizing test = new ImageSizing();
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.getContentPane().add(test.getPanel());
        f.setSize(400,400);
        f.setLocation(200,200);
        f.setVisible(true);
    }
}