Smooth image saling

Question

Hi,
Iam developing an Image Viewer application using ImageIO package(as I have to handle Tiff files).
Iam trying to scale a b&w tif file which is scanned with 300 dpi(2400X3162) using Graphics2D.scale() method and the quality is really bad for any scale factor below 0.5.
I tried setting anti-aliasing to true and there is no change in appearence.
Is there any better way to do this? Like implementing any better algorithms etc.
I tried JTiffy viewer(http://www.tiffy.de) and the quality is excellent for the same file.
Any suggestions please?
varma

Answer 1

Thanks a lot DrLaszloJamf for you quick response.
It works perfect for scaleFactor <=1 and I am amazed by the qualty of the image.
But throws OutOfMemory error for scaleFactor > 1 (1.1 to 2..). Here is my code.
BufferedImage image = null;                         
int w=0;
int h=0;
try
     ImageInputStream in = ImageIO.createImageInputStream(new FileInputStream(path));
     String ext = path.substring(path.lastIndexOf(".") + 1);
     ext = ext.trim();
     Iterator readers = ImageIO.getImageReadersBySuffix(ext);
     if (!readers.hasNext())
     throw new IOException("no readers");
     ImageReader reader = (ImageReader) readers.next();
     reader.setInput(in);
     ImageReadParam param = reader.getDefaultReadParam();
     int total = reader.getNumImages(true);
     System.out.println("Total Pages= " + total);
     System.out.println("Loading...");
     try
          int num = Integer.parseInt(pageNum);
          w = reader.getWidth(num);
          h = reader.getHeight(num);
          image = reader.read(num);
          MediaTracker tracker = new MediaTracker(new JFrame());
          tracker.addImage(image, 0);
          tracker.waitForID(0);
          System.out.println("Successfully Loaded");
     catch(Exception e)
          System.out.println("Load Error: " + e);
     reader.abort();
     reader.dispose();
     image.flush();
     ColorModel cm = null;
     try {
          PixelGrabber grabby = new PixelGrabber(image, 0, 0, 1, 1, false);
          if (!grabby.grabPixels())
               throw new RuntimeException("pixel grab fails");
          cm = grabby.getColorModel();
     catch (InterruptedException e) {
          throw new RuntimeException("interrupted", e);
     double scaleFactor = 1;
     try
          scaleFactor = Double.parseDouble(scale);
     catch(Exception se)
          System.out.println("scale Error: " + se);
     int reqWidth = (int)(w*scaleFactor);
     int reqHeight = (int)(h*scaleFactor);
     Image target = null;
     if(scaleFactor < 1)
     target = image.getScaledInstance(reqWidth, reqHeight, Image.SCALE_AREA_AVERAGING);
     else
          int transparency = cm.getTransparency();
          GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
          GraphicsDevice gd = ge.getDefaultScreenDevice();
          GraphicsConfiguration gc = gd.getDefaultConfiguration();
          BufferedImage target2 = gc.createCompatibleImage(reqWidth, reqHeight);
          Graphics2D g = target2.createGraphics();
          double scalex = (double) target2.getWidth() / w;
          double scaley = (double) target2.getHeight() / h;
          AffineTransform at = AffineTransform.getScaleInstance(scalex, scaley);
          g.drawRenderedImage(image, at);
          g.dispose();
          target = target2;
Then, Iam using the target image to be rendered in JPanel.
I also used createVolatileImage method of GraphicsConfiguration. But ended up with the same OutOfMemory error.
Is there any way that I can get arround this error?
Thank you.
varma