SV: sizing down an uploaded photo

Hi,

Quick and simple solution to the problem. The attached code scales down
images that are wider then the value stored in "MAX_IMAGE_WIDTH". To use the
method just pass your image as a BufferedImage to the method:

BufferedImage myScaledImg = scaleImage(ImageIO.read(new
File("/path/to/image.jpg")));

/* CODE: start */
private static final int MAX_IMAGE_WIDTH = 120;

private BufferedImage scaleImage(BufferedImage srcImage)
{
  //Get original size
  int imageWidth = srcImage.getWidth();
  int imageHeight = srcImage.getHeight();

  //Calculate scalingfactor
  double scale = (double)MAX_IMAGE_WIDTH / (double)srcImage.getWidth();

  //Now create thumbnail
  AffineTransform affineTransform = AffineTransform.getScaleInstance(scale,
scale);
  AffineTransformOp affineTransformOp = new
AffineTransformOp(affineTransform, null);
  BufferedImage scaledBufferedImage = affineTransformOp.filter(srcImage,
null);

  //Somewhere in AffineTransform there is a rounding error that
  //causes a thin line in the bottom of the scaled image.
  //The following code is adjusting this annoying "feature"
  int scaledWidth = scaledBufferedImage.getWidth();
  int scaledHeight = scaledBufferedImage.getHeight();
  int expectedWidth = (int)(imageWidth * scale);
  int expectedHeight = (int)(imageHeight * scale);
  if (scaledWidth > expectedWidth || scaledHeight > expectedHeight)
  {
    return scaledBufferedImage.getSubimage(0, 0, expectedWidth,
expectedHeight);
  }
  else
  {
    return scaledBufferedImage;
  }
}
/* CODE: end */

Brgds
Mathias


-----Ursprungligt meddelande-----
Från: A mailing list for discussion about Sun Microsystem's Java Servlet
API Technology. [mailto:[email protected]]För Carter, Scott
Skickat: den 7 maj 2003 00:03
Till: [email protected]
Ämne: sizing down an uploaded photo


I am hoping that someone using servlets has encountered this problem.  I
have a web site where user's can upload photos, but after the servlet
uploads the file I would like it to also resize the deminsions of the
picture and the quality (size).  Has anyone run into this problem?

Thanks - Scott

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