content: package ucesoft.cbm.misc;
  
  /**
   * Copyright (c) 2014-2016 by Wen Yu.
   * All rights reserved. This program and the accompanying materials
   * are made available under the terms of the Eclipse Public License v1.0
   * which accompanies this distribution, and is available at
   * http://www.eclipse.org/legal/epl-v10.html
   *
   * Any modifications to this file must keep this entire header intact.
   *
   * Change History - most recent changes go on top of previous changes
   *
   * AnimatedGIFWriter.java
   *
   * Who   Date       Description
   * ====  =========  =================================================
   * WY    29Oct2015  Crop image if outside of logical screen
   * WY    28Oct2015  Initial creation
   */
  
  import java.awt.*;
  import java.awt.image.BufferedImage;
  import java.awt.image.DataBuffer;
  import java.awt.image.IndexColorModel;
  import java.awt.image.Raster;
  import java.io.IOException;
  import java.io.OutputStream;
  import java.util.Arrays;
  import java.util.List;
  
  public class AnimatedGIFWriter {
      // Fields
      private int codeLen;
      private int codeIndex;
      private int clearCode;
      private int endOfImage;
      private int bufIndex;
      private int empty_bits = 0x08;
  
      private int bitsPerPixel = 0x08;
  
      private byte bytes_buf[] = new byte[256];
      private int[] colorPalette;
      private boolean isApplyDither;
  
      /**
       * A child is made up of a parent(or prefix) code plus a suffix color
       * and siblings are strings with a common parent(or prefix) and different
       * suffix colors
       */
      int child[] = new int[4097];
  
      int siblings[] = new int[4097];
      int suffix[] = new int[4097];
  
      private int logicalScreenWidth;
      private int logicalScreenHeight;
  
      private boolean animated;
      private int loopCount;
      private boolean firstFrame = true;
  
      // Define constants
      public static final byte IMAGE_SEPARATOR = 0x2c; // ","
      public static final byte IMAGE_TRAILER = 0x3b; // ";"
      public static final byte EXTENSION_INTRODUCER = 0x21; // "!"
      public static final byte GRAPHIC_CONTROL_LABEL = (byte)0xf9;
      public static final byte APPLICATION_EXTENSION_LABEL = (byte)0xff;
      public static final byte COMMENT_EXTENSION_LABEL = (byte)0xfe;
  
      private static final int MASK[] = {0x00, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f, 0xff};
  
      private static Dimension getLogicalScreenSize(BufferedImage[] images) {
          // Determine the logical screen dimension assuming all the frames have the same
          // left and top coordinates (0, 0)
          int logicalScreenWidth = 0;
          int logicalScreenHeight = 0;
  
          for(BufferedImage image : images) {
              if(image.getWidth() > logicalScreenWidth)
                  logicalScreenWidth = image.getWidth();
              if(image.getHeight() > logicalScreenHeight)
                  logicalScreenHeight = image.getHeight();
          }
  
          return new Dimension(logicalScreenWidth, logicalScreenHeight);
      }
  
      private static Dimension getLogicalScreenSize(GIFFrame[] frames) {
          // Determine the logical screen dimension given all the frames with different
          // left and top coordinates.
          int logicalScreenWidth = 0;
          int logicalScreenHeight = 0;
  
          for(GIFFrame frame : frames) {
              int frameRightPosition = frame.getFrameWidth() + frame.getLeftPosition();
              int frameBottomPosition = frame.getFrameHeight() + frame.getTopPosition();
              if(frameRightPosition > logicalScreenWidth)
                  logicalScreenWidth = frameRightPosition;
              if(frameBottomPosition > logicalScreenHeight)
                  logicalScreenHeight = frameBottomPosition;
          }
  
          return new Dimension(logicalScreenWidth, logicalScreenHeight);
      }
  
      public AnimatedGIFWriter() { this(false);}
  
      public AnimatedGIFWriter(boolean isApplyDither) {
          this.isApplyDither = isApplyDither;
      }
  
      // Write as a single frame GIF
      public void write(BufferedImage img, OutputStream os) throws Exception {
          if(img == null) throw new NullPointerException("Input image is null");
          int imageWidth = img.getWidth();
          int imageHeight = img.getHeight();
          write(getRGB(img), imageWidth, imageHeight, os);
      }
  
      private void encode(byte[] pixels, OutputStream os) throws Exception {
          // Define local variables
          int parent = 0;
          int son = 0;
          int brother = 0;
          int color = 0;
          int index = 0;
          int dimension = pixels.length;
  
          // Write out the length of the root
          os.write(bitsPerPixel = (bitsPerPixel == 1)?2:bitsPerPixel);
          // Initialize the encoder
          init_encoder(bitsPerPixel);
          // Tell the decoder to initialize the string table
          send_code_to_buffer(clearCode, os);
          // Get the first color and assign it to parent
          parent = (pixels[index++]&0xff);
  
          while (index < dimension)
          {
              color = (pixels[index++]&0xff);
              son = child[parent];
  
              if ( son > 0){
                  if (suffix[son] == color) {
                      parent = son;
                  } else {
                      brother = son;
                      while (true)
                      {
                          if (siblings[brother] > 0)
                          {
                              brother = siblings[brother];
                              if (suffix[brother] == color)
                              {
                                  parent = brother;
                                  break;
                              }
                          } else {
                              siblings[brother] = codeIndex;
                              suffix[codeIndex] = color;
                              send_code_to_buffer(parent,os);
                              parent = color;
                              codeIndex++;
                              // Check code length
                              if(codeIndex > ((1<<codeLen)))
                              {
                                  if (codeLen == 12)
                                  {
                                      send_code_to_buffer(clearCode,os);
                                      init_encoder(bitsPerPixel);
                                  } else
                                      codeLen++;
                              }
                              break;
                          }
                      }
                  }
              } else {
                  child[parent] = codeIndex;
                  suffix[codeIndex] = color;
                  send_code_to_buffer(parent,os);
                  parent = color;
                  codeIndex++;
                  // Check code length
                  if(codeIndex > ((1<<codeLen)))
                  {
                      if (codeLen == 12)
                      {
                          send_code_to_buffer(clearCode,os);
                          init_encoder(bitsPerPixel);
                      } else
                          codeLen++;
                  }
              }
          }
          // Send the last color code to the buffer
          send_code_to_buffer(parent,os);
          // Send the endOfImage code to the buffer
          send_code_to_buffer(endOfImage,os);
          // Flush the last code buffer
          flush_buf(os, bufIndex+1);
      }
  
      /**
       * This is intended to be called after writing all the frames if we write
       * an animated GIF frame by frame.
       *
       * @param os OutputStream for the animated GIF
       * @throws Exception
       */
      public void finishWrite(OutputStream os) throws Exception {
          os.write(IMAGE_TRAILER);
          os.close();
      }
  
      private void flush_buf(OutputStream os, int len) throws Exception {
          os.write(len);
          os.write(bytes_buf,0,len);
          // Clear the bytes buffer
          bufIndex = 0;
          Arrays.fill(bytes_buf, 0, 0xff, (byte)0x00);
      }
  
      /**
       * Retrieves RGB values from Raster. This seems to be the fastest way to get RGB values.
       *
       * TYPE_INT_RGB        = 1
       * TYPE_INT_ARGB       = 2
       * TYPE_INT_ARGB_PRE   = 3
       * TYPE_INT_BGR        = 4
       * TYPE_3BYTE_BGR      = 5
       * TYPE_4BYTE_ABGR     = 6
       * TYPE_4BYTE_ABGR_PRE = 7
       * TYPE_BYTE_GRAY      = 10
       * TYPE_BYTE_BINARY    = 12
       * TYPE_BYTE_INDEXED   = 13
       * TYPE_USHORT_GRAY    = 11
       * TYPE_USHORT_565_RGB = 8
       * TYPE_USHORT_555_RGB = 9
       * TYPE_CUSTOM         = 0.
       *
       * @param image input BufferedImage
       * @return integer array - default RGB color space representation
       */
      private static int[] getRGB(BufferedImage image) {
          // Get the BufferedImageType
          int type = image.getType();
          // Grab the internal data array
          Raster raster = image.getRaster();
          Object object = raster.getDataElements(0, 0, image.getWidth(), image.getHeight(), null);
          // Determine the data transfer type
          int transferType = raster.getTransferType();
          // Get image dimension
          int imageWidth = image.getWidth();
          int imageHeight = image.getHeight();
          int imageSize = imageWidth*imageHeight;
          int[] rgbs = new int[imageSize];
          // Branch by transfer type
          switch(transferType) {
              case DataBuffer.TYPE_INT:
                  rgbs = (int[])object;
                  if(type == BufferedImage.TYPE_INT_ARGB_PRE) {
                      for(int i = 0; i < imageSize; i++) {
                          float alpha = 255.0f/((rgbs[i]>>24)&0xff);
                          byte red = (byte)(((rgbs[i]>>16)&0xff)*alpha);
                          byte green = (byte)(((rgbs[i]>>8)&0xff)*alpha);
                          byte blue = (byte)((rgbs[i]&0xff)*alpha);
                          rgbs[i] = (rgbs[i]&0xff000000)|((red&0xff)<<16)|((green&0xff)<<8)|(blue&0xff);
                      }
                  } else if(type == BufferedImage.TYPE_INT_BGR) { // Convert BGR to RGB
                      for(int i = 0; i < rgbs.length; i++) {
                          int blue = (rgbs[i]>>16)&0xff;
                          int green = (rgbs[i]>>8) & 0xff;
                          int red = rgbs[i]&0xff;
                          rgbs[i] = 0xff000000|(red << 16)|(green << 8)|blue;
                      }
                  } else if(type == BufferedImage.TYPE_INT_RGB) {
                      for(int i = 0; i < rgbs.length; i++)
                          rgbs[i] = 0xff000000|rgbs[i];
                  } else if(type == BufferedImage.TYPE_INT_ARGB) {
                      ;  // Do nothing
                  } else {
                      return image.getRGB(0, 0, imageWidth, imageHeight, rgbs, 0, imageWidth);
                  }
                  return rgbs;
              case DataBuffer.TYPE_BYTE:
                  byte[] bpixels = (byte[])object;
                  // BufferedImage.getRGB() seems a bit faster in this case for small images.
                  if(type == BufferedImage.TYPE_BYTE_INDEXED || type == BufferedImage.TYPE_BYTE_BINARY) {
                      IndexColorModel indexModel = (IndexColorModel)image.getColorModel();
                      int mapSize = indexModel.getMapSize();
                      byte[] reds = new byte[mapSize];
                      byte[] greens = new byte[mapSize];
                      byte[] blues = new byte[mapSize];
                      byte[] alphas = new byte[mapSize];
                      int[] palette = new int[mapSize];
                      indexModel.getReds(reds);
                      indexModel.getGreens(greens);
                      indexModel.getBlues(blues);
                      indexModel.getAlphas(alphas);
                      for(int i = 0; i < mapSize; i++)
                          palette[i] = (alphas[i]&0xff)<<24|(reds[i]&0xff)<<16|(greens[i]&0xff)<<8|blues[i]&0xff;
                      for(int i = 0; i < imageSize; i++)
                          rgbs[i] = palette[bpixels[i]&0xff];
                  } else if(type == BufferedImage.TYPE_4BYTE_ABGR) {
                      for(int i = 0, index = 0; i < imageSize; i++)
                          rgbs[i] = (((bpixels[index++]&0xff)<<16)|((bpixels[index++]&0xff)<<8)|(bpixels[index++]&0xff)|((bpixels[index++]&0xff)<<24));
                  } else if(type == BufferedImage.TYPE_3BYTE_BGR) {
                      for(int i = 0, index = 0; i < imageSize; i++)
                          rgbs[i] = ((0xff000000)|((bpixels[index++]&0xff)<<16)|((bpixels[index++]&0xff)<<8)|(bpixels[index++]&0xff));
                  } else if(type == BufferedImage.TYPE_4BYTE_ABGR_PRE) {
                      for(int i = 0, index = 0; i < imageSize; i++, index += 4) {
                          float alpha = 255.0f*(bpixels[index+3]&0xff);
                          byte blue = (byte)((bpixels[index+2]&0xff)*alpha);
                          byte green = (byte)((bpixels[index+1]&0xff)*alpha);
                          byte red = (byte)((bpixels[index]&0xff)*alpha);
                          rgbs[i] =  (bpixels[index+3]&0xff000000)|((red&0xff)<<16)|((green&0xff)<<8)|(blue&0xff);
                      }
                  } else if(type == BufferedImage.TYPE_BYTE_GRAY) {
                      for(int i = 0; i < imageSize; i++)
                          rgbs[i] = (0xff000000)|((bpixels[i]&0xff)<<16)|((bpixels[i]&0xff)<<8)|(bpixels[i]&0xff);
                  } else {
                      return image.getRGB(0, 0, imageWidth, imageHeight, rgbs, 0, imageWidth);
                  }
                  return rgbs;
              case DataBuffer.TYPE_USHORT:
                  short[] spixels = (short[])object;
                  if(type == BufferedImage.TYPE_USHORT_GRAY) {
                      for(int i = 0; i < imageSize; i++) {
                          int gray = ((spixels[i]>>8)&0xff);
                          rgbs[i] = (0xff000000)|(gray<<16)|(gray<<8)|gray;
                      }
                  } else if(type == BufferedImage.TYPE_USHORT_565_RGB) {
                      for(int i = 0; i < imageSize; i++) {
                          int red = ((spixels[i]>>11)&0x1f);
                          int green = ((spixels[i]>>5)&0x3f);
                          int blue = (spixels[i]&0x1f);
                          rgbs[i] = (0xff000000)|(red<<19)|(green<<10)|(blue<<3);
                      }
                  } else if(type == BufferedImage.TYPE_USHORT_555_RGB) {
                      for(int i = 0; i < imageSize; i++) {
                          int red = ((spixels[i]>>>10)&0x1f);
                          int green = ((spixels[i]>>>5)&0x1f);
                          int blue = (spixels[i]&0x1f);
                          rgbs[i] = (0xff000000)|(red<<19)|(green<<11)|(blue<<3);
                      }
                  } else {
                      return image.getRGB(0, 0, imageWidth, imageHeight, rgbs, 0, imageWidth);
                  }
                  return rgbs;
              default:
                  return image.getRGB(0, 0, imageWidth, imageHeight, rgbs, 0, imageWidth);
          }
      }
  
      private void init_encoder(int bitsPerPixel ) {
          clearCode = 1 << bitsPerPixel;
          endOfImage = clearCode + 1;
          codeLen = bitsPerPixel + 1;
          codeIndex = endOfImage + 1;
          // Reset arrays
          Arrays.fill(child, 0);
          Arrays.fill(siblings, 0);
          Arrays.fill(suffix, 0);
      }
  
      /**
       * This is intended to be called first when writing an animated GIF
       * frame by frame.
       *
       * @param os OutputStream for the animated GIF
       * @param logicalScreenWidth width of the logical screen. If it is less than
       *        or equal zero, it will be determined from the first frame
       * @param logicalScreenHeight height of the logical screen. If it is less than
       *        or equal zero, it will be determined from the first frame
       * @throws Exception
       */
      public void prepareForWrite(OutputStream os, int logicalScreenWidth, int logicalScreenHeight) throws Exception {
          // Header first
          writeHeader(os, true);
          this.logicalScreenWidth = logicalScreenWidth;
          this.logicalScreenHeight = logicalScreenHeight;
          // We are going to write animated GIF, so enable animated flag
          animated = true;
      }
  
      // Translate codes into bytes
      private void send_code_to_buffer(int code, OutputStream os)throws Exception	{
          int temp = codeLen;
          // Shift the code to the left of the last byte in bytes_buf
          bytes_buf[bufIndex] |= ((code&MASK[empty_bits])<<(8-empty_bits));
          code >>= empty_bits;
          temp -= empty_bits;
          // If the code is longer than the empty_bits
          while (temp > 0)
          {
              if ( ++bufIndex >= 0xff)
              {
                  flush_buf(os,0xff);
              }
              bytes_buf[bufIndex] |= (code&0xff);
              code >>= 8;
              temp -= 8;
          }
          empty_bits = -temp;
      }
  
      public void setLoopCount(int loopCount) {
          this.loopCount = loopCount;
      }
  
      private void write(int[] pixels, int imageWidth, int imageHeight, OutputStream os) throws Exception {
          // Write GIF header
          writeHeader(os, true);
          // Set logical screen size
          logicalScreenWidth = imageWidth;
          logicalScreenHeight = imageHeight;
          firstFrame = true;
          // We only need to write one frame, so disable animated flag
          animated = false;
          // Write the image frame
          writeFrame(pixels, imageWidth, imageHeight, 0, 0, 0, os);
          // Make a clean end up of the image
          os.write(IMAGE_TRAILER);
          os.close();
      }
  
      /**
       * Writes an array of BufferedImage as an animated GIF
       *
       * @param images an array of BufferedImage
       * @param delays delays in millisecond for each frame
       * @param os OutputStream for the animated GIF
       * @throws Exception
       */
      public void writeAnimatedGIF(BufferedImage[] images, int[] delays, OutputStream os) throws Exception {
          // Header first
          writeHeader(os, true);
  
          Dimension logicalScreenSize = getLogicalScreenSize(images);
  
          logicalScreenWidth = logicalScreenSize.width;
          logicalScreenHeight = logicalScreenSize.height;
          // We are going to write animated GIF, so enable animated flag
          animated = true;
  
          for(int i = 0; i < images.length; i++) {
              // Retrieve image dimension
              int imageWidth = images[i].getWidth();
              int imageHeight = images[i].getHeight();
              writeFrame(getRGB(images[i]), imageWidth, imageHeight, 0, 0, delays[i], os);
          }
  
          os.write(IMAGE_TRAILER);
          os.close();
      }
  
      /**
       * Writes an array of GIFFrame as an animated GIF
       *
       * @param frames an array of GIFFrame
       * @param os OutputStream for the animated GIF
       * @throws Exception
       */
      public void writeAnimatedGIF(GIFFrame[] frames, OutputStream os) throws Exception {
          // Header first
          writeHeader(os, true);
  
          Dimension logicalScreenSize = getLogicalScreenSize(frames);
  
          logicalScreenWidth = logicalScreenSize.width;
          logicalScreenHeight = logicalScreenSize.height;
          // We are going to write animated GIF, so enable animated flag
          animated = true;
  
          for(int i = 0; i < frames.length; i++) {
              // Retrieve image dimension
              int imageWidth = frames[i].getFrameWidth();
              int imageHeight = frames[i].getFrameHeight();
              int[] pixels = getRGB(frames[i].getFrame());
              if(frames[i].getTransparencyFlag() == GIFFrame.TRANSPARENCY_INDEX_SET && frames[i].getTransparentColor() != -1) {
                  int transColor = (frames[i].getTransparentColor() & 0x00ffffff);
                  for(int j = pixels.length - 1; j > 0; j--) {
                      int pixel = (pixels[j] & 0x00ffffff);
                      if(pixel == transColor) pixels[j] = pixel;
                  }
              }
              writeFrame(pixels, imageWidth, imageHeight, frames[i].getLeftPosition(), frames[i].getTopPosition(),
                      frames[i].getDelay(), frames[i].getDisposalMethod(), frames[i].getUserInputFlag(), os);
          }
  
          os.write(IMAGE_TRAILER);
          os.close();
      }
  
      /**
       * Writes a list of GIFFrame as an animated GIF
       *
       * @param frames a list of GIFFrame
       * @param os OutputStream for the animated GIF
       * @throws Exception
       */
      public void writeAnimatedGIF(List<GIFFrame> frames, OutputStream os) throws Exception {
          writeAnimatedGIF(frames.toArray(new GIFFrame[0]), os);
      }
  
      private void writeComment(OutputStream os, String comment) throws Exception {
          os.write(EXTENSION_INTRODUCER);
          os.write(COMMENT_EXTENSION_LABEL);
          byte[] commentBytes = comment.getBytes();
          int numBlocks = commentBytes.length/0xff;
          int leftOver = commentBytes.length % 0xff;
          int offset = 0;
          if(numBlocks > 0) {
              for(int i = 0; i < numBlocks; i++) {
                  os.write(0xff);
                  os.write(commentBytes, offset, 0xff);
                  offset += 0xff;
              }
          }
          if(leftOver > 0) {
              os.write(leftOver);
              os.write(commentBytes, offset, leftOver);
          }
          os.write(0);
      }
  
      public void writeFrame(OutputStream os, GIFFrame frame) throws Exception {
          // Retrieve image dimension
          BufferedImage image = frame.getFrame();
          int imageWidth = image.getWidth();
          int imageHeight = image.getHeight();
          int frameLeft = frame.getLeftPosition();
          int frameTop = frame.getTopPosition();
          // Determine the logical screen dimension
          if(firstFrame) {
              if(logicalScreenWidth <= 0)
                  logicalScreenWidth = imageWidth;
              if(logicalScreenHeight <= 0)
                  logicalScreenHeight = imageHeight;
          }
          if(frameLeft >= logicalScreenWidth || frameTop >= logicalScreenHeight) return;
          if((frameLeft + imageWidth) > logicalScreenWidth) imageWidth = logicalScreenWidth - frameLeft;
          if((frameTop + imageHeight) > logicalScreenHeight) imageHeight = logicalScreenHeight - frameTop;
          int[] pixels = getRGB(image.getSubimage(0, 0, imageWidth, imageHeight));
          // Handle transparency color if explicitly set
          if(frame.getTransparencyFlag() == GIFFrame.TRANSPARENCY_INDEX_SET && frame.getTransparentColor() != -1) {
              int transColor = (frame.getTransparentColor() & 0x00ffffff);
              for(int j = pixels.length - 1; j > 0; j--) {
                  int pixel = (pixels[j] & 0x00ffffff);
                  if(pixel == transColor) pixels[j] = pixel;
              }
          }
          writeFrame(pixels, imageWidth, imageHeight, frame.getLeftPosition(), frame.getTopPosition(),
                  frame.getDelay(), frame.getDisposalMethod(), frame.getUserInputFlag(), os);
      }
  
      public void writeFrame(OutputStream os, BufferedImage frame) throws Exception {
          writeFrame(os, frame, 100); // default delay is 100 milliseconds
      }
  
      public void writeFrame(OutputStream os, BufferedImage frame, int delay) throws Exception {
          // Retrieve image dimension
          int imageWidth = frame.getWidth();
          int imageHeight = frame.getHeight();
          // Determine the logical screen dimension
          if(firstFrame) {
              if(logicalScreenWidth <= 0)
                  logicalScreenWidth = imageWidth;
              if(logicalScreenHeight <= 0)
                  logicalScreenHeight = imageHeight;
          }
          if(delay <= 0) delay = 100;
          if(imageWidth > logicalScreenWidth) imageWidth = logicalScreenWidth;
          if(imageHeight > logicalScreenHeight) imageHeight = logicalScreenHeight;
          writeFrame(getRGB(frame.getSubimage(0, 0, imageWidth, imageHeight)), imageWidth, imageHeight, 0, 0, delay, os);
      }
  
      private void writeFrame(int[] pixels, int imageWidth, int imageHeight, int imageLeftPosition, int imageTopPosition, int delay, int disposalMethod, int userInputFlag, OutputStream os) throws Exception {
          // Reset empty_bits
          empty_bits = 0x08;
  
          int transparent_color = -1;
          int[] colorInfo;
  
          // Reduce colors, if the color depth is less than 8 bits, reduce colors
          // to the actual bits needed, otherwise reduce to 8 bits.
          byte[] newPixels = new byte[imageWidth*imageHeight];
          colorPalette = new int[256];
  
          colorInfo = checkColorDepth(pixels, newPixels, colorPalette);
  
          if(colorInfo[0] > 0x08) {
              bitsPerPixel = 8;
              if(isApplyDither)
                  colorInfo = reduceColorsDiffusionDither(pixels, imageWidth, imageHeight, bitsPerPixel, newPixels, colorPalette);
              else
                  colorInfo = reduceColors(pixels, bitsPerPixel, newPixels, colorPalette);
          }
  
          bitsPerPixel = colorInfo[0];
  
          transparent_color = colorInfo[1];
  
          int num_of_color = 1<<bitsPerPixel;
  
          if(firstFrame) {
              // Logical screen descriptor
              byte  flags = (byte)0x88;//0b10001000 (having sorted global color map) - To be updated
              byte  bgcolor = 0x00;// To be set
              byte  aspectRatio = 0x00;
              int colorResolution = 0x07;
              // Set GIF logical screen descriptor parameters
              flags |= ((colorResolution<<4)|(bitsPerPixel - 1));
              if(transparent_color >= 0)
                  bgcolor = (byte)transparent_color;
              // Write logical screen descriptor
              writeLSD(os, (short)logicalScreenWidth, (short)logicalScreenHeight, flags, bgcolor, aspectRatio);
              // Write the global colorPalette
              writePalette(os, num_of_color);
              writeComment(os, "Created by ICAFE - https://github.com/dragon66/icafe");
              if(animated)// Write Netscape extension block
                  writeNetscapeApplicationBlock(os, loopCount);
          }
  
          // Output the graphic control block
          writeGraphicControlBlock(os, delay, transparent_color, disposalMethod, userInputFlag);
          // Output image descriptor
          if(firstFrame) {
              writeImageDescriptor(os, imageWidth, imageHeight, imageLeftPosition, imageTopPosition, -1);
              firstFrame = false;
          } else {
              writeImageDescriptor(os, imageWidth, imageHeight, imageLeftPosition, imageTopPosition, bitsPerPixel - 1);
              // Write local colorPalette
              writePalette(os, num_of_color);
          }
          // LZW encode the image
          encode(newPixels, os);
          /** Write out a zero length data sub-block */
          os.write(0x00);
      }
  
      private void writeFrame(int[] pixels, int imageWidth, int imageHeight, int imageLeftPosition, int imageTopPosition, int delay, OutputStream os) throws Exception	{
          writeFrame(pixels, imageWidth, imageHeight, imageLeftPosition, imageTopPosition, delay, GIFFrame.DISPOSAL_RESTORE_TO_BACKGROUND, GIFFrame.USER_INPUT_NONE, os);
      }
  
      // Unit of delay is supposed to be in millisecond
      private void writeGraphicControlBlock(OutputStream os, int delay, int transparent_color, int disposalMethod, int userInputFlag) throws Exception {
          // Scale delay
          delay = Math.round(delay/10.0f);
  
          byte[] buf = new byte[8];
          buf[0] = EXTENSION_INTRODUCER; // Extension introducer
          buf[1] = GRAPHIC_CONTROL_LABEL; // Graphic control label
          buf[2] = 0x04; // Block size
          // Add disposalMethod and userInputFlag
          buf[3] |= (((disposalMethod&0x07) << 2)|((userInputFlag&0x01) << 1));
          buf[4] = (byte)(delay&0xff);// Delay time
          buf[5] = (byte)((delay>>8)&0xff);
          buf[6] = (byte)transparent_color;
          buf[7] = 0x00;
  
          if(transparent_color >= 0) // Add transparency indicator
              buf[3] |= 0x01;
  
          os.write(buf, 0, 8);
      }
  
      private void writeHeader(OutputStream os, boolean newFormat) throws IOException {
          // 6 bytes: GIF signature (always "GIF") plus GIF version ("87a" or "89a")
          if(newFormat)
              os.write("GIF89a".getBytes());
          else
              os.write("GIF87a".getBytes());
      }
  
      private void writeImageDescriptor(OutputStream os, int imageWidth, int imageHeight, int imageLeftPosition, int imageTopPosition, int colorTableSize) throws Exception {
          byte imageDescriptor[] = new byte[10];
          imageDescriptor[0] = IMAGE_SEPARATOR;// Image separator ","
          imageDescriptor[1] = (byte)(imageLeftPosition&0xff);// Image left position
          imageDescriptor[2] = (byte)((imageLeftPosition>>8)&0xff);
          imageDescriptor[3] = (byte)(imageTopPosition&0xff);// Image top position
          imageDescriptor[4] = (byte)((imageTopPosition>>8)&0xff);
          imageDescriptor[5] = (byte)(imageWidth&0xff);
          imageDescriptor[6] = (byte)((imageWidth>>8)&0xff);
          imageDescriptor[7] = (byte)(imageHeight&0xff);
          imageDescriptor[8] = (byte)((imageHeight>>8)&0xff);
          imageDescriptor[9] = (byte)0x20;//0b00100000 - Packed fields
  
          if(colorTableSize >= 0) // Local color table will follow
              imageDescriptor[9] |= (1<<7|colorTableSize);
  
          os.write(imageDescriptor, 0, 10);
      }
  
      // Write logical screen descriptor
      private void writeLSD(OutputStream os, short screen_width, short screen_height, short flags, byte bgcolor, byte aspectRatio) throws IOException	{
          byte[] descriptor = new byte[7];
          // Screen_width
          descriptor[0] = (byte)(screen_width&0xff);
          descriptor[1] = (byte)((screen_width>>8)&0xff);
          // Screen_height
          descriptor[2] = (byte)(screen_height&0xff);
          descriptor[3] = (byte)((screen_height>>8)&0xff);
          // Global flags
          descriptor[4] = (byte)(flags&0xff);
          // Background color
          descriptor[5] = bgcolor;
          // AspectRatio
          descriptor[6] = aspectRatio;
  
          os.write(descriptor);
      }
  
      private void writeNetscapeApplicationBlock(OutputStream os, int loopCounts) throws Exception {
          byte[] buf = new byte[19];
          buf[0] = EXTENSION_INTRODUCER; // Extension introducer
          buf[1] = APPLICATION_EXTENSION_LABEL; // Application extension label
          buf[2] = 0x0b; // Block size
          buf[3] = 'N'; // Application Identifier (8 bytes)
          buf[4] = 'E';
          buf[5] = 'T';
          buf[6] = 'S';
          buf[7] = 'C';
          buf[8] = 'A';
          buf[9] = 'P';
          buf[10]= 'E';
          buf[11]= '2';// Application Authentication Code (3 bytes)
          buf[12]= '.';
          buf[13]= '0';
          buf[14]= 0x03;
          buf[15]= 0x01;
          buf[16]= (byte)(loopCounts&0xff); // Loop counts
          buf[17]= (byte)((loopCounts>>8)&0xff);
          buf[18]= 0x00; // Block terminator
  
          os.write(buf);
      }
  
      private void writePalette(OutputStream os, int num_of_color) throws Exception {
          int index = 0;
          byte colors[] = new byte[num_of_color*3];
  
          for (int i=0; i<num_of_color; i++)
          {
              colors[index++] = (byte)(((colorPalette[i]>>16)&0xff));
              colors[index++] = (byte)(((colorPalette[i]>>8)&0xff));
              colors[index++] = (byte)(colorPalette[i]&0xff);
          }
  
          os.write(colors, 0, num_of_color*3);
      }
  
      private static int[] checkColorDepth(int[] rgbTriplets, byte[] newPixels, final int[] colorPalette) {
          int index = 0;
          int temp = 0;
          int bitsPerPixel = 1;
          int transparent_index = -1;// Transparent color index
          int transparent_color = -1;// Transparent color
          int[] colorInfo = new int[2];// Return value
  
          IntHashtable<Integer> rgbHash = new IntHashtable<Integer>(1023);
  
          for (int i = 0; i < rgbTriplets.length; i++) {
              temp = (rgbTriplets[i]&0x00ffffff);
  
              if((rgbTriplets[i] >>> 24) < 0x80 ) { // Transparent
                  if (transparent_index < 0) {
                      transparent_index = index;
                      transparent_color = temp;// Remember transparent color
                  }
                  temp = Integer.MAX_VALUE;
              }
  
              Integer entry = rgbHash.get(temp);
  
              if (entry!=null) {
                  newPixels[i] = entry.byteValue();
              } else {
                  if(index > 0xff) {// More than 256 colors, have to reduce
                      // Colors before saving as an indexed color image
                      colorInfo[0] = 24;
                      return colorInfo;
                  }
                  rgbHash.put(temp, index);
                  newPixels[i] = (byte)index;
                  colorPalette[index++] = ((0xff<<24)|temp);
              }
          }
          if(transparent_index >= 0)// This line could be used to set a different background color
              colorPalette[transparent_index] = transparent_color;
          // Return the actual bits per pixel and the transparent color index if any
          while ((1<<bitsPerPixel)<index)  bitsPerPixel++;
  
          colorInfo[0] = bitsPerPixel;
          colorInfo[1] = transparent_index;
  
          return colorInfo;
      }
  
      private static int[] reduceColorsDiffusionDither(int[] rgbTriplets, int width, int height, int colorDepth, byte[] newPixels, final int[] colorPalette)	{
          if(colorDepth > 8 || colorDepth < 1)
              throw new IllegalArgumentException("Invalid color depth " + colorDepth);
          int[] colorInfo = new int[2];
          int colors = 0;
          colors = new WuQuant(rgbTriplets, 1<<colorDepth).quantize(colorPalette, colorInfo);
          // Call Floyd-Steinberg dither
          dither_FloydSteinberg(rgbTriplets, width, height, newPixels, colors, colorPalette, colorInfo[1]);
          // Return the actual bits per pixel and the transparent color index if any
  
          return colorInfo;
      }
  
      // Color quantization
      private static int[] reduceColors(int[] rgbTriplets, int colorDepth, byte[] newPixels, final int[] colorPalette)	{
          int[] colorInfo = new int[2];
          new WuQuant(rgbTriplets, 1<<colorDepth).quantize(newPixels, colorPalette, colorInfo);
  
          return colorInfo;
      }
  
      private static void dither_FloydSteinberg(int[] rgbTriplet, int width, int height, byte[] newPixels, int no_of_color,
                                                int[] colorPalette, int transparent_index)
      {
          int index = 0, index1 = 0, err1, err2, err3, red, green, blue;
          // Define error arrays
          // Errors for the current line
          int[] tempErr;
          int[] thisErrR = new int[width + 2];
          int[] thisErrG = new int[width + 2];
          int[] thisErrB = new int[width + 2];
          // Errors for the following line
          int[] nextErrR = new int[width + 2];
          int[] nextErrG = new int[width + 2];
          int[] nextErrB = new int[width + 2];
  
          InverseColorMap invMap;
  
          invMap = new InverseColorMap();
          invMap.createInverseMap(no_of_color, colorPalette);
  
          for (int row = 0; row < height; row++) {
              for (int col = 0; col < width; index1++, col++)	{
                  // Transparent, no dither
                  if((rgbTriplet[index1] >>> 24) < 0x80 ) {
                      newPixels[index1] = (byte)transparent_index;
                      continue;
                  }
  
                  red = ((rgbTriplet[index1]&0xff0000)>>>16) + thisErrR[col + 1];
                  if (red > 255) red = 255;
                  else if (red < 0) red = 0;
  
                  green = ((rgbTriplet[index1]&0x00ff00)>>>8) + thisErrG[col + 1];
                  if (green > 255) green = 255;
                  else if (green < 0) green = 0;
  
                  blue = (rgbTriplet[index1]&0x0000ff) + thisErrB[col + 1];
                  if (blue > 255) blue = 255;
                  else if (blue < 0) blue = 0;
  
                  // Find the nearest color index
                  index = invMap.getNearestColorIndex(red, green, blue);
                  newPixels[index1] = (byte)index;// The colorPalette index for this pixel
  
                  // Find errors for different channels
                  err1 = red   - ((colorPalette[index]>>16)&0xff);// Red channel
                  err2 = green - ((colorPalette[index]>>8)&0xff);// Green channel
                  err3 = blue  -  (colorPalette[index]&0xff);// Blue channel
                  // Diffuse error
                  // Red
                  thisErrR[col + 2] += ((err1*7)/16);
                  nextErrR[col    ] += ((err1*3)/16);
                  nextErrR[col + 1] += ((err1*5)/16);
                  nextErrR[col + 2] += ((err1)/16);
                  // Green
                  thisErrG[col + 2] += ((err2*7)/16);
                  nextErrG[col    ] += ((err2*3)/16);
                  nextErrG[col + 1] += ((err2*5)/16);
                  nextErrG[col + 2] += ((err2)/16);
                  // Blue
                  thisErrB[col + 2] += ((err3*7)/16);
                  nextErrB[col    ] += ((err3*3)/16);
                  nextErrB[col + 1] += ((err3*5)/16);
                  nextErrB[col + 2] += ((err3)/16);
              }
              // We have finished one row, switch the error arrays
              tempErr = thisErrR;
              thisErrR = nextErrR;
              nextErrR = tempErr;
  
              tempErr = thisErrG;
              thisErrG = nextErrG;
              nextErrG = tempErr;
  
              tempErr = thisErrB;
              thisErrB = nextErrB;
              nextErrB = tempErr;
  
              // Clear the error arrays
              Arrays.fill(nextErrR, 0);
              Arrays.fill(nextErrG, 0);
              Arrays.fill(nextErrB, 0);
          }
      }
  
      public static class GIFFrame {
          // Frame parameters
          private BufferedImage frame;
          private int leftPosition;
          private int topPosition;
          private int frameWidth;
          private int frameHeight;
          private int delay;
          private int disposalMethod = DISPOSAL_UNSPECIFIED;
          private int userInputFlag = USER_INPUT_NONE;
          private int transparencyFlag = TRANSPARENCY_INDEX_NONE;
  
          // The transparent color value in RRGGBB format.
          // The highest order byte has no effect.
          private int transparentColor = TRANSPARENCY_COLOR_NONE; // Default no transparent color
  
          public static final int DISPOSAL_UNSPECIFIED = 0;
          public static final int DISPOSAL_LEAVE_AS_IS = 1;
          public static final int DISPOSAL_RESTORE_TO_BACKGROUND = 2;
          public static final int DISPOSAL_RESTORE_TO_PREVIOUS = 3;
          // Values between 4-7 inclusive
          public static final int DISPOSAL_TO_BE_DEFINED = 7;
  
          public static final int USER_INPUT_NONE = 0;
          public static final int USER_INPUT_EXPECTED = 1;
  
          public static final int TRANSPARENCY_INDEX_NONE = 0;
          public static final int TRANSPARENCY_INDEX_SET = 1;
  
          public static final int TRANSPARENCY_COLOR_NONE = -1;
  
          public GIFFrame(BufferedImage frame) {
              this(frame, 0, 0, 0, GIFFrame.DISPOSAL_UNSPECIFIED);
          }
  
          public GIFFrame(BufferedImage frame, int delay) {
              this(frame, 0, 0, delay, GIFFrame.DISPOSAL_UNSPECIFIED);
          }
  
          public GIFFrame(BufferedImage frame, int delay, int disposalMethod) {
              this(frame, 0, 0, delay, disposalMethod);
          }
  
          public GIFFrame(BufferedImage frame, int leftPosition, int topPosition, int delay, int disposalMethod) {
              this(frame, leftPosition, topPosition, delay, disposalMethod, USER_INPUT_NONE, TRANSPARENCY_INDEX_NONE, TRANSPARENCY_COLOR_NONE);
          }
  
          public GIFFrame(BufferedImage frame, int leftPosition, int topPosition, int delay, int disposalMethod, int userInputFlag, int transparencyFlag, int transparentColor) {
              if(frame == null) throw new IllegalArgumentException("Null input image");
              if(disposalMethod < DISPOSAL_UNSPECIFIED || disposalMethod > DISPOSAL_TO_BE_DEFINED)
                  throw new IllegalArgumentException("Invalid disposal method: " + disposalMethod);
              if(userInputFlag < USER_INPUT_NONE || userInputFlag > USER_INPUT_EXPECTED)
                  throw new IllegalArgumentException("Invalid user input flag: " + userInputFlag);
              if(transparencyFlag < TRANSPARENCY_INDEX_NONE || transparencyFlag > TRANSPARENCY_INDEX_SET)
                  throw new IllegalArgumentException("Invalid transparency flag: " + transparencyFlag);
              if(leftPosition < 0 || topPosition < 0)
                  throw new IllegalArgumentException("Negative coordinates for frame top-left position");
              if(delay < 0) delay = 0;
              this.frame = frame;
              this.leftPosition = leftPosition;
              this.topPosition = topPosition;
              this.delay = delay;
              this.disposalMethod = disposalMethod;
              this.userInputFlag = userInputFlag;
              this.transparencyFlag = transparencyFlag;
              this.frameWidth = frame.getWidth();
              this.frameHeight = frame.getHeight();
              this.transparentColor = transparentColor;
          }
  
          public int getDelay() {
              return delay;
          }
  
          public int getDisposalMethod() {
              return disposalMethod;
          }
  
          public BufferedImage getFrame() {
              return frame;
          }
  
          public int getFrameHeight() {
              return frameHeight;
          }
  
          public int getFrameWidth() {
              return frameWidth;
          }
  
          public int getLeftPosition() {
              return leftPosition;
          }
  
          public int getTopPosition() {
              return topPosition;
          }
  
          public int getTransparentColor() {
              return transparentColor;
          }
  
          public int getTransparencyFlag() {
              return transparencyFlag;
          }
  
          public int getUserInputFlag() {
              return userInputFlag;
          }
      }
  
      /**
       * Java port of
       * C Implementation of Wu's Color Quantizer (v. 2)
       * (see Graphics Gems vol. II, pp. 126-133)
       * Author:	Xiaolin Wu
       * Dept. of Computer Science
       * Univ. of Western Ontario
       * London, Ontario N6A 5B7
       * wu@csd.uwo.ca
       *
       * Algorithm: Greedy orthogonal bipartition of RGB space for variance
       * minimization aided by inclusion-exclusion tricks.
       * For speed no nearest neighbor search is done. Slightly
       * better performance can be expected by more sophisticated
       * but more expensive versions.
       *
       * The author thanks Tom Lane at Tom_Lane@G.GP.CS.CMU.EDU for much of
       * additional documentation and a cure to a previous bug.
       *
       * Free to distribute, comments and suggestions are appreciated.
       */
      private static class WuQuant {
          private static final int MAXCOLOR =	256;
          private static final int RED = 2;
          private static final int GREEN = 1;
          private static final int BLUE =	0;
  
          private static int QUANT_SIZE = 33;// quant size
  
          private static final class Box {
              int r0;	 /* min value, exclusive */
              int r1;	 /* max value, inclusive */
              int g0;
              int g1;
              int b0;
              int b1;
              int vol;
          };
  
          private int	size; /*image size*/
          private int	lut_size; /*color look-up table size*/
          private int qadd[];
          private int pixels[];
          private int transparent_color = -1;// Transparent color
  
          private float m2[][][] = new float[QUANT_SIZE][QUANT_SIZE][QUANT_SIZE];
          private long wt[][][] = new long[QUANT_SIZE][QUANT_SIZE][QUANT_SIZE];
          private long mr[][][] = new long[QUANT_SIZE][QUANT_SIZE][QUANT_SIZE];
          private long mg[][][] = new long[QUANT_SIZE][QUANT_SIZE][QUANT_SIZE];
          private long mb[][][] = new long[QUANT_SIZE][QUANT_SIZE][QUANT_SIZE];
  
          public WuQuant(int[] pixels, int lut_size) {
              this.pixels = pixels;
              this.size = pixels.length;
              this.lut_size = lut_size;
          }
  
          public int quantize(final byte[] newPixels, final int[] lut, int[] colorInfo) {
              Box cube[] = new Box[MAXCOLOR];
              int lut_r, lut_g, lut_b;
              int tag[] = new int[QUANT_SIZE*QUANT_SIZE*QUANT_SIZE];
  
              int next, i, k;
              long weight;
              float vv[] = new float[MAXCOLOR], temp;
  
              Hist3d(wt, mr, mg, mb, m2);
              M3d(wt, mr, mg, mb, m2);
  
              for(i = 0; i < MAXCOLOR; i++)
                  cube[i] = new Box();
  
              cube[0].r0 = cube[0].g0 = cube[0].b0 = 0;
              cube[0].r1 = cube[0].g1 = cube[0].b1 = QUANT_SIZE - 1;
              next = 0;
  
              if(transparent_color >= 0) lut_size--;
  
              for(i = 1; i < lut_size; ++i){
                  if (Cut(cube[next], cube[i])) {
                      /* volume test ensures we won't try to cut one-cell box */
                      vv[next] = (cube[next].vol > 1) ? Var(cube[next]) : 0.0f;
                      vv[i] = (cube[i].vol > 1) ? Var(cube[i]) : 0.0f;
                  } else {
                      vv[next] = 0.0f;   /* don't try to split this box again */
                      i--;              /* didn't create box i */
                  }
                  next = 0; temp = vv[0];
                  for(k = 1; k <= i; ++k)
                      if (vv[k] > temp) {
                          temp = vv[k]; next = k;
                      }
                  if (temp <= 0.0f) {
                      k = i + 1;
                      break;
                  }
              }
  
              for(k = 0; k < lut_size; ++k){
                  Mark(cube[k], k, tag);
                  weight = Vol(cube[k], wt);
                  if (weight > 0) {
                      lut_r = (int)(Vol(cube[k], mr) / weight);
                      lut_g = (int)(Vol(cube[k], mg) / weight);
                      lut_b = (int)(Vol(cube[k], mb) / weight);
                      lut[k] = (255 << 24) | (lut_r  << 16) | (lut_g << 8) | lut_b;
                  }
                  else	{
                      lut[k] = 0;
                  }
              }
  
              for(i = 0; i < size; ++i) {
                  if((pixels[i] >>> 24) < 0x80)
                      newPixels[i] = (byte)lut_size;
                  else
                      newPixels[i] = (byte)tag[qadd[i]];
              }
  
              int bitsPerPixel = 0;
              while ((1<<bitsPerPixel) < lut_size)  bitsPerPixel++;
              colorInfo[0] = bitsPerPixel;
              colorInfo[1] = -1;
  
              if(transparent_color >= 0) {
                  lut[lut_size] = transparent_color; // Set the transparent color
                  colorInfo[1] = lut_size;
              }
  
              return lut_size;
          }
  
          public int quantize(final int[] lut, int[] colorInfo) {
              Box cube[] = new Box[MAXCOLOR];
              int lut_r, lut_g, lut_b;
  
              int next, i, k;
              long weight;
              float vv[] = new float[MAXCOLOR], temp;
  
              Hist3d(wt, mr, mg, mb, m2);
              M3d(wt, mr, mg, mb, m2);
  
              for(i = 0; i < MAXCOLOR; i++)
                  cube[i] = new Box();
  
              cube[0].r0 = cube[0].g0 = cube[0].b0 = 0;
              cube[0].r1 = cube[0].g1 = cube[0].b1 = QUANT_SIZE - 1;
              next = 0;
  
              if(transparent_color >= 0) lut_size--;
  
              for(i = 1; i < lut_size; ++i){
                  if (Cut(cube[next], cube[i])) {
                      /* volume test ensures we won't try to cut one-cell box */
                      vv[next] = (cube[next].vol > 1) ? Var(cube[next]) : 0.0f;
                      vv[i] = (cube[i].vol > 1) ? Var(cube[i]) : 0.0f;
                  } else {
                      vv[next] = 0.0f;   /* don't try to split this box again */
                      i--;              /* didn't create box i */
                  }
                  next = 0; temp = vv[0];
                  for(k = 1; k <= i; ++k)
                      if (vv[k] > temp) {
                          temp = vv[k]; next = k;
                      }
                  if (temp <= 0.0f) {
                      k = i + 1;
                      break;
                  }
              }
  
              for(k = 0; k < lut_size; ++k){
                  weight = Vol(cube[k], wt);
                  if (weight > 0) {
                      lut_r = (int)(Vol(cube[k], mr) / weight);
                      lut_g = (int)(Vol(cube[k], mg) / weight);
                      lut_b = (int)(Vol(cube[k], mb) / weight);
                      lut[k] = (255 << 24) | (lut_r  << 16) | (lut_g << 8) | lut_b;
                  }
                  else	{
                      lut[k] = 0;
                  }
              }
  
              int bitsPerPixel = 0;
              while ((1<<bitsPerPixel) < lut_size)  bitsPerPixel++;
              colorInfo[0] = bitsPerPixel;
              colorInfo[1] = -1;
  
              if(transparent_color >= 0) {
                  lut[lut_size] = transparent_color; // Set the transparent color
                  colorInfo[1] = lut_size;
              }
  
              return lut_size;
          }
  
          /* Histogram is in elements 1..HISTSIZE along each axis,
           * element 0 is for base or marginal value
           * NB: these must start out 0!
           */
          private void Hist3d(long vwt[][][], long vmr[][][], long vmg[][][], long vmb[][][], float m2[][][]) {
              /* build 3-D color histogram of counts, r/g/b, c^2 */
              int r, g, b;
              int	i, inr, ing, inb, table[] = new int[256];
  
              for(i = 0; i < 256; ++i) table[i]= i*i;
  
              qadd = new int[size];
  
              for(i = 0; i < size; ++i) {
                  int rgb = pixels[i];
                  if((rgb >>> 24) < 0x80) { // Transparent
                      if (transparent_color < 0)	// Find the transparent color
                          transparent_color = rgb;
                  }
                  r = ((rgb >> 16)& 0xff);
                  g = ((rgb >> 8 )& 0xff);
                  b = ( rgb       & 0xff);
                  inr = (r >> 3) + 1;
                  ing = (g >> 3) + 1;
                  inb = (b >> 3) + 1;
                  qadd[i] = (inr << 10) + (inr << 6) + inr + (ing << 5) + ing + inb;
                  /*[inr][ing][inb]*/
                  ++vwt[inr][ing][inb];
                  vmr[inr][ing][inb] += r;
                  vmg[inr][ing][inb] += g;
                  vmb[inr][ing][inb] += b;
                  m2[inr][ing][inb] += table[r] + table[g] + table[b];
              }
          }
  
          /* At conclusion of the histogram step, we can interpret
           *   wt[r][g][b] = sum over voxel of P(c)
           *   mr[r][g][b] = sum over voxel of r*P(c)  ,  similarly for mg, mb
           *   m2[r][g][b] = sum over voxel of c^2*P(c)
           * Actually each of these should be divided by 'size' to give the usual
           * interpretation of P() as ranging from 0 to 1, but we needn't do that here.
           */
  
          /* We now convert histogram into moments so that we can rapidly calculate
           * the sums of the above quantities over any desired box.
           */
          private void M3d(long vwt[][][], long vmr[][][], long vmg[][][], long vmb[][][], float m2[][][]) {
              /* compute cumulative moments. */
              int i, r, g, b;
              int line, line_r, line_g, line_b;
              int area[] = new int[QUANT_SIZE];
              int area_r[] = new int[QUANT_SIZE];
              int area_g[] = new int[QUANT_SIZE];
              int area_b[] = new int[QUANT_SIZE];
              float line2, area2[] = new float[QUANT_SIZE];
  
              for(r = 1; r < QUANT_SIZE; ++r) {
                  for(i = 0; i < QUANT_SIZE; ++i)
                      area2[i] = area[i] = area_r[i] = area_g[i] = area_b[i] = 0;
                  for(g = 1; g < QUANT_SIZE; ++g) {
                      line2 = line = line_r = line_g = line_b = 0;
                      for(b = 1; b < QUANT_SIZE; ++b){
                          line   += vwt[r][g][b];
                          line_r += vmr[r][g][b];
                          line_g += vmg[r][g][b];
                          line_b += vmb[r][g][b];
                          line2  += m2[r][g][b];
  
                          area[b] += line;
                          area_r[b] += line_r;
                          area_g[b] += line_g;
                          area_b[b] += line_b;
                          area2[b] += line2;
  
                          vwt[r][g][b] = vwt[r-1][g][b] + area[b];
                          vmr[r][g][b] = vmr[r-1][g][b] + area_r[b];
                          vmg[r][g][b] = vmg[r-1][g][b] + area_g[b];
                          vmb[r][g][b] = vmb[r-1][g][b] + area_b[b];
                          m2[r][g][b]  = m2[r-1][g][b]  + area2[b];
                      }
                  }
              }
          }
  
          private long Vol(Box cube, long mmt[][][]) {
              /* Compute sum over a box of any given statistic */
              return ( mmt[cube.r1][cube.g1][cube.b1]
                      -mmt[cube.r1][cube.g1][cube.b0]
                      -mmt[cube.r1][cube.g0][cube.b1]
                      +mmt[cube.r1][cube.g0][cube.b0]
                      -mmt[cube.r0][cube.g1][cube.b1]
                      +mmt[cube.r0][cube.g1][cube.b0]
                      +mmt[cube.r0][cube.g0][cube.b1]
                      -mmt[cube.r0][cube.g0][cube.b0] );
          }
  
          /* The next two routines allow a slightly more efficient calculation
           * of Vol() for a proposed subbox of a given box.  The sum of Top()
           * and Bottom() is the Vol() of a subbox split in the given direction
           * and with the specified new upper bound.
           */
  
          private long Bottom(Box cube, int dir, long mmt[][][]) {
              /* Compute part of Vol(cube, mmt) that doesn't depend on r1, g1, or b1 */
              /* (depending on dir) */
              switch(dir) {
                  case RED:
                      return( -mmt[cube.r0][cube.g1][cube.b1]
                              +mmt[cube.r0][cube.g1][cube.b0]
                              +mmt[cube.r0][cube.g0][cube.b1]
                              -mmt[cube.r0][cube.g0][cube.b0] );
                  case GREEN:
                      return( -mmt[cube.r1][cube.g0][cube.b1]
                              +mmt[cube.r1][cube.g0][cube.b0]
                              +mmt[cube.r0][cube.g0][cube.b1]
                              -mmt[cube.r0][cube.g0][cube.b0] );
                  case BLUE:
                      return( -mmt[cube.r1][cube.g1][cube.b0]
                              +mmt[cube.r1][cube.g0][cube.b0]
                              +mmt[cube.r0][cube.g1][cube.b0]
                              -mmt[cube.r0][cube.g0][cube.b0] );
                  default:
                      return 0;
              }
          }
  
          private long Top(Box cube, int dir, int pos, long mmt[][][]) {
              /* Compute remainder of Vol(cube, mmt), substituting pos for */
              /* r1, g1, or b1 (depending on dir) */
              switch(dir) {
                  case RED:
                      return( mmt[pos][cube.g1][cube.b1]
                              -mmt[pos][cube.g1][cube.b0]
                              -mmt[pos][cube.g0][cube.b1]
                              +mmt[pos][cube.g0][cube.b0] );
                  case GREEN:
                      return( mmt[cube.r1][pos][cube.b1]
                              -mmt[cube.r1][pos][cube.b0]
                              -mmt[cube.r0][pos][cube.b1]
                              +mmt[cube.r0][pos][cube.b0] );
                  case BLUE:
                      return( mmt[cube.r1][cube.g1][pos]
                              -mmt[cube.r1][cube.g0][pos]
                              -mmt[cube.r0][cube.g1][pos]
                              +mmt[cube.r0][cube.g0][pos] );
                  default:
                      return 0;
              }
          }
  
          private float Var(Box cube) {
              /* Compute the weighted variance of a box */
              /* NB: as with the raw statistics, this is really the variance * size */
              float dr, dg, db, xx;
              dr = Vol(cube, mr);
              dg = Vol(cube, mg);
              db = Vol(cube, mb);
              xx =  m2[cube.r1][cube.g1][cube.b1]
                      -m2[cube.r1][cube.g1][cube.b0]
                      -m2[cube.r1][cube.g0][cube.b1]
                      +m2[cube.r1][cube.g0][cube.b0]
                      -m2[cube.r0][cube.g1][cube.b1]
                      +m2[cube.r0][cube.g1][cube.b0]
                      +m2[cube.r0][cube.g0][cube.b1]
                      -m2[cube.r0][cube.g0][cube.b0];
              return  xx - (dr*dr + dg*dg + db*db)/Vol(cube,wt);
          }
  
          /* We want to minimize the sum of the variances of two subboxes.
           * The sum(c^2) terms can be ignored since their sum over both subboxes
           * is the same (the sum for the whole box) no matter where we split.
           * The remaining terms have a minus sign in the variance formula,
           * so we drop the minus sign and MAXIMIZE the sum of the two terms.
           */
          private float Maximize(Box cube, int dir, int first, int last, int cut[],
                                 long whole_r, long whole_g, long whole_b, long whole_w) {
              long half_r, half_g, half_b, half_w;
              long base_r, base_g, base_b, base_w;
              int i;
              float temp, max;
  
              base_r = Bottom(cube, dir, mr);
              base_g = Bottom(cube, dir, mg);
              base_b = Bottom(cube, dir, mb);
              base_w = Bottom(cube, dir, wt);
  
              max = 0.0f;
              cut[0] = -1;
  
              for(i = first; i < last; ++i){
                  half_r = base_r + Top(cube, dir, i, mr);
                  half_g = base_g + Top(cube, dir, i, mg);
                  half_b = base_b + Top(cube, dir, i, mb);
                  half_w = base_w + Top(cube, dir, i, wt);
                  /* now half_x is sum over lower half of box, if split at i */
                  if (half_w == 0) /* subbox could be empty of pixels! */
                      continue;    /* never split into an empty box */
                  temp = (half_r*half_r + half_g*half_g +	half_b*half_b)/(float)half_w;
                  half_r = whole_r - half_r;
                  half_g = whole_g - half_g;
                  half_b = whole_b - half_b;
                  half_w = whole_w - half_w;
                  if (half_w == 0) /* subbox could be empty of pixels! */
                      continue; /* never split into an empty box */
                  temp += (half_r*half_r + half_g*half_g + half_b*half_b)/(float)half_w;
  
                  if (temp > max) { max = temp; cut[0] = i;}
              }
  
              return max;
          }
  
          private boolean Cut(Box set1, Box set2) {
              int dir;
              int cutr[] = new int[1];
              int cutg[] = new int[1];
              int cutb[] = new int[1];
              float maxr, maxg, maxb;
              long whole_r, whole_g, whole_b, whole_w;
  
              whole_r = Vol(set1, mr);
              whole_g = Vol(set1, mg);
              whole_b = Vol(set1, mb);
              whole_w = Vol(set1, wt);
  
              maxr = Maximize(set1, RED, set1.r0 + 1, set1.r1, cutr,
                      whole_r, whole_g, whole_b, whole_w);
              maxg = Maximize(set1, GREEN, set1.g0 + 1, set1.g1, cutg,
                      whole_r, whole_g, whole_b, whole_w);
              maxb = Maximize(set1, BLUE, set1.b0 + 1, set1.b1, cutb,
                      whole_r, whole_g, whole_b, whole_w);
  
              if(maxr >= maxg && maxr >= maxb) {
                  dir = RED;
                  if (cutr[0] < 0) return false; /* can't split the box */
              } else if(maxg >= maxr && maxg >= maxb)
                  dir = GREEN;
              else
                  dir = BLUE;
  
              set2.r1 = set1.r1;
              set2.g1 = set1.g1;
              set2.b1 = set1.b1;
  
              switch (dir){
                  case RED:
                      set2.r0 = set1.r1 = cutr[0];
                      set2.g0 = set1.g0;
                      set2.b0 = set1.b0;
                      break;
                  case GREEN:
                      set2.g0 = set1.g1 = cutg[0];
                      set2.r0 = set1.r0;
                      set2.b0 = set1.b0;
                      break;
                  case BLUE:
                      set2.b0 = set1.b1 = cutb[0];
                      set2.r0 = set1.r0;
                      set2.g0 = set1.g0;
                      break;
              }
              set1.vol = (set1.r1 - set1.r0)*(set1.g1 - set1.g0)*(set1.b1 - set1.b0);
              set2.vol = (set2.r1 - set2.r0)*(set2.g1 - set2.g0)*(set2.b1 - set2.b0);
  
              return true;
          }
  
          private void Mark(Box cube, int label, int tag[]) {
              int r, g, b;
  
              for(r = cube.r0 + 1; r <= cube.r1; ++r)
                  for(g = cube.g0 + 1; g <= cube.g1; ++g)
                      for(b = cube.b0 + 1; b <= cube.b1; ++b)
                          tag[(r<<10) + (r<<6) + r + (g<<5) + g + b] = label;
          }
      }
  
      /**
       * A hash table using primitive integer keys.
       *
       * Based on
       * QuadraticProbingHashTable.java
       * <p>
       * Probing table implementation of hash tables.
       * Note that all "matching" is based on the equals method.
       *
       * @author Mark Allen Weiss
       */
      private static class IntHashtable<E> {
  
          /** The array of HashEntry. */
          private HashEntry<E> [ ] array;  // The array of HashEntry
          private int currentSize;  // The number of occupied cells
  
          /**
           * Construct the hash table.
           * @param size the approximate initial size.
           */
          @SuppressWarnings("unchecked")
          public IntHashtable(int size) {
              array = new HashEntry [size];
              makeEmpty( );
          }
  
          /**
           * Insert into the hash table. If the item is
           * already present, do nothing.
           * @param key the item to insert.
           */
          public void put(int key, E value) {
              // Insert key as active
              int currentPos = locate( key );
              if( isActive( currentPos ) )
                  return;
  
              array[ currentPos ] = new HashEntry<E> ( key, value, true );
  
              // Rehash
              if( ++currentSize > array.length / 2 )
                  rehash( );
          }
  
          /**
           * Expand the hash table.
           */
          @SuppressWarnings("unchecked")
          private void rehash( ) {
              HashEntry<E> [ ] oldArray = array;
  
              // Create a new double-sized, empty table
              array = new HashEntry [nextPrime( 2 * oldArray.length )];
              currentSize = 0;
  
              // Copy table over
              for( int i = 0; i < oldArray.length; i++ )
                  if( oldArray[i] != null && oldArray[i].isActive )
                      put( oldArray[i].key, oldArray[i].value );
  
              return;
          }
  
          /**
           * Method that performs quadratic probing resolution.
           * @param key the item to search for.
           * @return the index of the item.
           */
          private int locate(int key) {
              int collisionNum = 0;
  
              // And with the largest positive integer
              int currentPos = (key & 0x7FFFFFFF) % array.length;
  
              while( array[ currentPos ] != null &&
                      array[ currentPos ].key != key )
              {
                  currentPos += 2 * ++collisionNum - 1;  // Compute ith probe
                  if( currentPos >= array.length )       // Implement the mod
                      currentPos -= array.length;
              }
              return currentPos;
          }
  
          /**
           * Find an item in the hash table.
           * @param key the item to search for.
           * @return the value of the matching item.
           */
          public E get(int key) {
              int currentPos = locate( key );
              return isActive( currentPos ) ? array[ currentPos ].value : null;
          }
  
          /**
           * Return true if currentPos exists and is active.
           * @param currentPos the result of a call to findPos.
           * @return true if currentPos is active.
           */
          private boolean isActive( int currentPos ) {
              return array[ currentPos ] != null && array[ currentPos ].isActive;
          }
  
          /**
           * Make the hash table logically empty.
           */
          public void makeEmpty( ) {
              currentSize = 0;
              for( int i = 0; i < array.length; i++ )
                  array[ i ] = null;
          }
  
          /**
           * Internal method to find a prime number at least as large as n.
           * @param n the starting number (must be positive).
           * @return a prime number larger than or equal to n.
           */
          private static int nextPrime(int n) {
              if( n % 2 == 0 )
                  n++;
  
              for( ; !isPrime( n ); n += 2 )
                  ;
  
              return n;
          }
  
          /**
           * Internal method to test if a number is prime.
           * Not an efficient algorithm.
           * @param n the number to test.
           * @return the result of the test.
           */
          private static boolean isPrime(int n) {
              if( n == 2 || n == 3 )
                  return true;
  
              if( n == 1 || n % 2 == 0 )
                  return false;
  
              for( int i = 3; i * i <= n; i += 2 )
                  if( n % i == 0 )
                      return false;
  
              return true;
          }
  
          // The basic entry stored in ProbingHashTable
          private static class HashEntry<V> {
              int key;         // the key
              V value;       // the value
              boolean  isActive;  // false if deleted
  
              @SuppressWarnings("unused")
              HashEntry(int k, V val) {
                  this( k, val, true );
              }
  
              HashEntry(int k, V val, boolean i) {
                  key = k;
                  value = val;
                  isActive  = i;
              }
          }
      }
  
      private static class InverseColorMap {
          private int bitsReserved;// Number of bits used in color quantization.
          private int bitsDiscarded;// Number of discarded bits
          private int maxColorVal;// Maximum value for each quantized color
          private int invMapLen;// Length of the inverse color map
          // The inverse color map itself
          private byte[] invColorMap;
  
          // Default constructor using 5 for quantization bits
          public InverseColorMap() {
              this(5);
          }
  
          // Constructor using bitsReserved bits for quantization
          public InverseColorMap(int rbits) {
              bitsReserved = rbits;
              bitsDiscarded  = 8 - bitsReserved;
              maxColorVal = 1 << bitsReserved;
              invMapLen = maxColorVal * maxColorVal * maxColorVal;
              invColorMap = new byte[invMapLen];
          }
  
          // Fetch the forward color map index for this RGB
          public int getNearestColorIndex(int red, int green, int blue) {
              return invColorMap[(((red >> bitsDiscarded) << (bitsReserved<<1))) |
                      ((green >> bitsDiscarded) << bitsReserved) |
                      (blue >> bitsDiscarded)]&0xff;
          }
  
          /**
           * Create an inverse color map using the input forward RGB map.
           */
          public void createInverseMap(int no_of_colors, int[] colorPalette) {
              int red, green, blue, r, g, b;
              int rdist, gdist, bdist, dist;
              int rinc, ginc, binc;
  
              int x = (1 << bitsDiscarded);// Step size for each color
              int xsqr = (1 << (bitsDiscarded + bitsDiscarded));
              int txsqr = xsqr + xsqr;
              int buf_index;
  
              int[] dist_buf = new int[invMapLen];
  
              // Initialize the distance buffer array with the largest integer value
              for (int i = invMapLen; --i >= 0;)
                  dist_buf[i] = 0x7FFFFFFF;
              // Now loop through all the colors in the color map
              for (int i = 0; i < no_of_colors; i++)
              {
                  red   = ((colorPalette[i]>>16)&0xff);
                  green = ((colorPalette[i]>>8)&0xff);
                  blue  = (colorPalette[i]&0xff);
                  /**
                   * We start from the origin (0,0,0) of the quantized colors, calculate
                   * the distance between the cell center of the quantized colors and
                   * the current color map entry as follows:
                   * (rcenter * x + x/2) - red, where rcenter is the center of the
                   * Quantized red color map entry which is 0 since we start from 0.
                   */
                  rdist = (x>>1) - red;// Red distance
                  gdist = (x>>1) - green;// Green distance
                  bdist = (x>>1) - blue;// Blue distance
                  dist = rdist*rdist + gdist*gdist + bdist*bdist;//The modular
                  // The distance increment with each step value x
                  rinc = txsqr - (red   << (bitsDiscarded + 1));
                  ginc = txsqr - (green << (bitsDiscarded + 1));
                  binc = txsqr - (blue  << (bitsDiscarded + 1));
  
                  buf_index = 0;
                  // Loop through quantized RGB space
                  for (r = 0, rdist = dist; r < maxColorVal; rdist += rinc, rinc += txsqr, r++ )
                  {
                      for (g = 0, gdist = rdist; g < maxColorVal; gdist += ginc, ginc += txsqr, g++)
                      {
                          for (b = 0, bdist = gdist; b < maxColorVal; bdist += binc, binc += txsqr, buf_index++, b++)
                          {
                              if (bdist < dist_buf[buf_index])
                              {
                                  dist_buf[buf_index] = bdist;
                                  invColorMap[buf_index] = (byte)i;
                              }
                          }
                      }
                  }
              }
          }
      }
  }
  