How to resize GIF images

Question

Hi
I used acme.jar to wirte gif images to a local disk . i worked fine , but iam facing problem in resizing these images , when i resize these images i get black background color in tat images .. can any body help me regarding this.....
thumbImage = scaleToSize(imageWidth, imageHeight, thumbImage);
Graphics2D graphics2D = thumbImage.createGraphics();
graphics2D.setRenderingHint(RenderingHints.KEY_INTERPOLATION,
     RenderingHints.VALUE_INTERPOLATION_BILINEAR);
     graphics2D.drawImage(image,0,0,     thumbWidth,thumbHeight,null);
out = new BufferedOutputStream(new FileOutputStream(newFilePath));
GifEncoder gife = new GifEncoder(image,out);     
gife.encode();
this is my code .....

Answer 1

Following is my code:
public final String dealFile(ActionMapping mapping,ActionForm form,
               HttpServletRequest request) throws FileNotFoundException, IOException{
          GroupForm gForm = (GroupForm) form;
          ActionMessages errors = new ActionMessages();
          // retrieve the file representation
          FormFile file = gForm.getPictFile();
          if (file == null) {
               errors.add("FileNeeded", new ActionMessage("error.photo.filenull"));
               saveErrors(request, errors);
               return "failure";
          // has the maximum length been exceeded?
          Boolean maxLengthExceeded = (Boolean) request
                    .getAttribute(MultipartRequestHandler.ATTRIBUTE_MAX_LENGTH_EXCEEDED);
          if ((maxLengthExceeded != null) && (maxLengthExceeded.booleanValue())) {
               errors.add("maxLengthExceeded", new ActionMessage(
                         "error.photo.length"));
               saveErrors(request, errors);
               return "failure";
          // retrieve the file name
          String fileName = file.getFileName();
          // judge file type
          String fileType = fileName.substring(fileName.lastIndexOf(".") + 1);
          if (!(fileType.equalsIgnoreCase("jpg")
                    || fileType.equalsIgnoreCase("jpeg")
                    || fileType.equalsIgnoreCase("gif") || fileType
                    .equalsIgnoreCase("png"))) {
               errors.add("NotPict", new ActionMessage("error.photo.wrongformat"));
               saveErrors(request, errors);
               return "failure";
          Date date = new Date();
          Random r = new Random(date.getTime());
          // ������������
          String newFileName = request.getSession().getId() + r.nextInt(10000)
                    + "." + fileType;
          String filePath = null;
          String newFilePath = null;
          // the directory to upload to
          String uploadDir = servlet.getServletContext()
                    .getRealPath("/resources")
                    + "/groupphoto/" + DateUtil.asShortString(date)+"/";
          // prepare directory if not exists
          File dirPath = new File(uploadDir);
          if (!dirPath.exists()) {
               dirPath.mkdirs();
          // retrieve the file data
          InputStream stream = file.getInputStream();
          // write the file to the file specified
          OutputStream bos = new FileOutputStream(uploadDir + newFileName);
          int bytesRead = 0;
          byte[] buffer = new byte[8192];
          while ((bytesRead = stream.read(buffer, 0, 8192)) != -1) {
               bos.write(buffer, 0, bytesRead);
          bos.close();
          buffer = null;
          filePath = dirPath.getAbsolutePath() + Constants.FILE_SEP
                    + newFileName;
          File _file = new File(uploadDir + newFileName);
          Image src = ImageIO.read(_file); // ����Image����
          int width = src.getWidth(null); // ����������
          int height = src.getHeight(null);// ����������
          // convert the picture to picture within 100x100 and save to a file with
          // prefix
          // 100x100_ for later listing purpose.
          newFilePath = dirPath.getAbsolutePath() +Constants.FILE_SEP
                    + "100x100_" + newFileName;
          int newWidth = 0;
          int newHeight = 0;
          int bigger = width <= height ? height : width;
          if (bigger > 100) {
               if (width >= height) {
                    newWidth = 100;
                    newHeight = height * 100 / width;
               } else {
                    newHeight = 100;
                    newWidth = width * 100 / height;
               ImageUtil.convert(filePath, newFilePath, newWidth, newHeight);
          // close the stream
          stream.close();
          _file = null;
          src = null;
          dirPath = null;
          String url = request.getContextPath() + "/resources" + "/groupphoto/"
          + DateUtil.asShortString(date)+"/"+ "100x100_" + newFileName;
          return url;          
     }