Resizing JPEG images

Question

Hey guys,
I have the following code:
public static void resize(String original, String resized, int size,
                              int dimension, float factor)
            throws Exception
        if ((dimension != HEIGHT) && (dimension != WIDTH))
            dimension = WIDTH;
        try
            // get original image
            Image originalImage = new ImageIcon(original).getImage();
            Image resizedImage = null;
            int imageWidth = originalImage.getWidth(null);
            int imageHeight = originalImage.getHeight(null);
            if (dimension == WIDTH)
                resizedImage = originalImage.getScaledInstance(
                        size, (size * imageHeight) / imageWidth,
                        Image.SCALE_SMOOTH);
            else
                resizedImage = originalImage.getScaledInstance(
                        (size * imageWidth) / imageHeight, size,
                        Image.SCALE_SMOOTH);
            // this code ensures that all the pixels in the image are loaded
            Image temp = new ImageIcon(resizedImage).getImage();
            // create the buffered image
            BufferedImage bufferedImage = new
BufferedImage(temp.getWidth(null),
                    temp.getHeight(null), BufferedImage.TYPE_INT_RGB);
            // copy image to buffered image
            Graphics g = bufferedImage.createGraphics();
            // clear background and paint the image
            g.setColor(Color.white);
            g.fillRect(0, 0, temp.getWidth(null), temp.getHeight(null));
            g.drawImage(temp, 0, 0, null);
            g.dispose();
            // sharpen/soften (depending on factor (-ve for sharpening, +ve
for softening)
            float[] array = {0, factor, 0, factor, 1 - (factor * 4),
                factor, 0, factor, 0};
            Kernel kernel = new Kernel(3, 3, array);
            ConvolveOp cOp = new ConvolveOp(kernel, ConvolveOp.EDGE_NO_OP,
null);
            bufferedImage = cOp.filter(bufferedImage, null);
            // write the jpeg to a file
            OutputStream out = new FileOutputStream(resized);
            // encodes image as a JPEG data stream
            JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
            com.sun.image.codec.jpeg.JPEGEncodeParam param =
encoder.getDefaultJPEGEncodeParam(bufferedImage);
            param.setQuality(0.7f, true);
            encoder.setJPEGEncodeParam(param);
            encoder.encode(bufferedImage);
        catch (Exception e)
            throw e;
    }which I use for making thumbnails and resizing images uploaded to my site. Thumbnails work fine (possibly due to the smaller size) but when I resize an image I get lots of horizontal lines across resized image.
The funny think is that when I use this method just in a simple application, running directly under JDK 1.4.1_02 then everything works fine and images turn out fine.
When the above code runs as a part of my web application, thumbnails work, but larger images end up with the lines across them.
Any ideas??
I thought it might have had something to do with the factor parameter I use so I tested it just using 0.0 and the same problem occurs.
I run Apache 2.0.44 with Tomcat 4.1.18, which by the way also runs with JDK 1.4.1_02 so JDK is not the problem.
Any help is greatly appreciated.
Cheers,
Tom

Answer 1

hey tom,
i also use this code and also had these problems. i solved it by adding just one line after your if-else: originalImage.flush();
else {
resizedImage = originalImage.getScaledInstance (size * imageWidth)/imageHeight, size, Image.SCALE_SMOOTH);
originalImage.flush();
// this code ensures that all the pixels in the image are loaded
Image temp = new ImageIcon(resizedImage).getImage();
.