AnimatedGifEncoder.java

package com.yeejay.im.library.gifdecode;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Arrays;

import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.Log;

import com.yeejay.im.library.log.MyLog;

/**
 * Gif编码压缩
 */
public class AnimatedGifEncoder {

    protected int width; // 图片帧的宽度
    protected int height; // 图片帧的高度
    protected int x = 0;
    protected int y = 0;
    protected int transparent = -1; // transparent color if given
    protected int transIndex; // transparent index in color table
    protected int repeat = -1; // 重复设置，0表示无限重复
    protected int delay = 0; // frame delay (hundredths)
    protected boolean started = false; // ready to output frames
    protected OutputStream out;
    protected Bitmap image; // 当前帧
    protected byte[] pixels; // BGR byte array from frame
    protected byte[] indexedPixels; // converted frame indexed to palette
    protected int colorDepth; // number of bit planes
    protected byte[] colorTab; // RGB palette
    protected boolean[] usedEntry = new boolean[256]; // active palette entries
    protected int palSize = 7; // color table size (bits-1)
    protected int dispose = -1; // disposal code (-1 = use default)
    protected boolean closeStream = true; // close stream when finished
    protected boolean firstFrame = true;
    protected boolean sizeSet = false; // if false, get size from first frame
    protected int sample = 10; // default sample interval for quantizer

    /**
     * Sets the delay time between each frame, or changes it for subsequent frames
     * (applies to last frame added).
     *
     * @param ms int delay time in milliseconds
     */
    public void setDelay(int ms) {
        delay = ms / 10;
    }

    public void setDelayNotDivide(int ms) {
        delay = ms ;
    }

    /**
     * Sets the GIF frame disposal code for the last added frame and any
     * subsequent frames. Default is 0 if no transparent color has been set,
     * otherwise 2.
     *
     * @param code int disposal code.
     */
    public void setDispose(int code) {
        if (code >= 0) {
            dispose = code;
        }
    }

    /**
     * Sets the number of times the set of GIF frames should be played. Default is
     * 1; 0 means play indefinitely. Must be invoked before the first image is
     * added.
     *
     * @param iter int number of iterations.
     * @return
     */
    public void setRepeat(int iter) {
        if (iter >= 0) {
            repeat = iter;
        }
    }

    /**
     * Sets the transparent color for the last added frame and any subsequent
     * frames. Since all colors are subject to modification in the quantization
     * process, the color in the final palette for each frame closest to the given
     * color becomes the transparent color for that frame. May be set to null to
     * indicate no transparent color.
     *
     * @param c Color to be treated as transparent on display.
     */
    public void setTransparent(int c) {
        //MyLog.w("GifTest  setTransparent = " + c);
        transparent = c;
    }

    /**
     * Adds next GIF frame. The frame is not written immediately, but is actually
     * deferred until the next frame is received so that timing data can be
     * inserted. Invoking <code>finish()</code> flushes all frames. If
     * <code>setSize</code> was not invoked, the size of the first image is used
     * for all subsequent frames.
     *
     * @param im BufferedImage containing frame to write.
     * @return true if successful.
     */
    public boolean addFrame(Bitmap im,boolean compressBitmap) {
        if ((im == null) || !started) {
            return false;
        }
        boolean ok = true;
        try {
            if (compressBitmap){
//                MyLog.i("---压缩帧前:w="+im.getWidth()+",h="+im.getHeight()+",size="+im.getByteCount());
                try{
//                   Bitmap temp = Bitmap.createScaledBitmap(im, (int) (im.getWidth()*0.6f), (int) (im.getHeight()*0.6f), true);

                    byte[] bytes = byteArrayFromBitmap(im,100);
                    BitmapFactory.Options options = new BitmapFactory.Options();
                    options.inPreferredConfig = Config.ARGB_4444;
                    options.inSampleSize = 2;
                    Bitmap temp = BitmapFactory.decodeByteArray(bytes,0,bytes.length,options);
                   if (temp != null){
                       im.recycle();
                       im = temp;
//                       MyLog.i("---压缩帧后:w="+im.getWidth()+",h="+im.getHeight()+",size="+im.getByteCount());
                   }
                }catch (OutOfMemoryError e){
                    e.printStackTrace();
                }
            }
            image = im;
            if (!sizeSet) {
                // use first frame's size
                setSize(im.getWidth(), im.getHeight());
            }

            getImagePixels(); // convert to correct format if necessary
            analyzePixels(); // build color table & map pixels
            if (firstFrame) {
                writeLSD(); // logical screen descriptior
                writePalette(); // global color table
                if (repeat >= 0) {
                    // use NS app extension to indicate reps
                    writeNetscapeExt();
                }
            }
            writeGraphicCtrlExt(); // write graphic control extension
            writeImageDesc(); // image descriptor
            if (!firstFrame) {
                writePalette(); // local color table
            }
            writePixels(); // encode and write pixel data
            firstFrame = false;
        } catch (IOException e) {
            e.printStackTrace();
            ok = false;
        } catch (OutOfMemoryError e){
            e.printStackTrace();
        }

        return ok;
    }


    public boolean addFrame(Bitmap im, boolean compressBitmap, int maxWidth) {
        if ((im == null) || !started) {
            return false;
        }
        boolean ok = true;
        try {

            if(compressBitmap){

    //                MyLog.i("---压缩帧前:w="+im.getWidth()+",h="+im.getHeight()+",size="+im.getByteCount());
                try{
    //                   Bitmap temp = Bitmap.createScaledBitmap(im, (int) (im.getWidth()*0.6f), (int) (im.getHeight()*0.6f), true);
                    byte[] bytes = byteArrayFromBitmap(im,100);
                    BitmapFactory.Options options = new BitmapFactory.Options();
                    options.inJustDecodeBounds = true;
                    BitmapFactory.decodeByteArray(bytes,0,bytes.length,options);
                    int sampleSize = 1;
                    if(options.outWidth > options.outHeight && options.outWidth > maxWidth){
                        sampleSize = (int) (options.outWidth / (float)maxWidth);
                    }else if(options.outHeight >= options.outWidth && options.outHeight > maxWidth){
                        sampleSize = (int) (options.outHeight / (float)maxWidth);
                    }
                    if(sampleSize < 1){
                        sampleSize = 1;
                    }
                    MyLog.w("compressSticker  sampleSize = " + sampleSize);
                    options.inJustDecodeBounds = false;
                    options.inPreferredConfig = Config.ARGB_4444;
                    options.inSampleSize = sampleSize;
                    Bitmap temp = BitmapFactory.decodeByteArray(bytes,0,bytes.length,options);
                    if (temp != null){
                        im.recycle();
                        im = temp;
    //                       MyLog.i("---压缩帧后:w="+im.getWidth()+",h="+im.getHeight()+",size="+im.getByteCount());
                    }
                }catch (OutOfMemoryError e){
                    e.printStackTrace();
                }
            }

            image = im;

            if (!sizeSet) {
                // use first frame's size
                setSize(im.getWidth(), im.getHeight());
            }

            getImagePixels(); // convert to correct format if necessary
            analyzePixels(); // build color table & map pixels
            if (firstFrame) {
                writeLSD(); // logical screen descriptior
                writePalette(); // global color table
                if (repeat >= 0) {
                    // use NS app extension to indicate reps
                    writeNetscapeExt();
                }
            }
            writeGraphicCtrlExt(); // write graphic control extension
            writeImageDesc(); // image descriptor
            if (!firstFrame) {
                writePalette(); // local color table
            }

            writePixels(); // encode and write pixel data
            firstFrame = false;
        } catch (IOException e) {
            e.printStackTrace();
            ok = false;
        } catch (OutOfMemoryError e){
            e.printStackTrace();
        }

        return ok;
    }


    public byte[] byteArrayFromBitmap(Bitmap bitmap, int percent){
        byte[] data = null;
        ByteArrayOutputStream baos = null;
        try {
            baos = new ByteArrayOutputStream();
            bitmap.compress(Bitmap.CompressFormat.PNG, percent, baos);
            data = baos.toByteArray();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if(baos != null) {
                    baos.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return data;
    }

    /**
     * Flushes any pending data and closes output file. If writing to an
     * OutputStream, the stream is not closed.
     */
    public boolean finish() {
        if (!started)
            return false;
        boolean ok = true;
        started = false;
        try {
            out.write(0x3b); // gif trailer
            out.flush();
            if (closeStream) {
                out.close();
            }
        } catch (IOException e) {
            ok = false;
        }

        // reset for subsequent use
        transIndex = 0;
        out = null;
        image = null;
        pixels = null;
        indexedPixels = null;
        colorTab = null;
        closeStream = false;
        firstFrame = true;

        return ok;
    }

    /**
     * Sets frame rate in frames per second. Equivalent to
     * <code>setDelay(1000/fps)</code>.
     *
     * @param fps float frame rate (frames per second)
     */
    public void setFrameRate(float fps) {
        if (fps != 0f) {
            delay = (int) (100 / fps);
        }
    }

    /**
     * Sets quality of color quantization (conversion of images to the maximum 256
     * colors allowed by the GIF specification). Lower values (minimum = 1)
     * produce better colors, but slow processing significantly. 10 is the
     * default, and produces good color mapping at reasonable speeds. Values
     * greater than 20 do not yield significant improvements in speed.
     *
     * @param quality int greater than 0.
     *                经测试，数值越小，压缩时间越久,颜色越清晰
     *                数值越大，压缩时间越快(40M的图片压缩2分钟)
     * @return
     */
    public void setQuality(int quality) {
        if (quality < 1)
            quality = 1;
        sample = quality;
    }

    /**
     * Sets the GIF frame size. The default size is the size of the first frame
     * added if this method is not invoked.
     *
     * @param w int frame width.
     * @param h int frame width.
     */
    public void setSize(int w, int h) {
        width = w;
        height = h;
        if (width < 1)
            width = 320;
        if (height < 1)
            height = 240;
        sizeSet = true;
    }

    public int getWidth(){
        return width;
    }

    public int getHeight(){
        return height;
    }

    /**
     * Sets the GIF frame position. The position is 0,0 by default.
     * Useful for only updating a section of the image
     *
     * @param x int frame width.
     * @param y int frame width.
     */
    public void setPosition(int x, int y) {
        this.x = x;
        this.y = y;
    }

    /**
     * Initiates GIF file creation on the given stream. The stream is not closed
     * automatically.
     *
     * @param os OutputStream on which GIF images are written.
     * @return false if initial write failed.
     */
    public boolean start(OutputStream os) {
        if (os == null)
            return false;
        boolean ok = true;
        closeStream = false;
        out = os;
        try {
            writeString("GIF89a"); // header
        } catch (IOException e) {
            e.printStackTrace();
            ok = false;
        }
        return started = ok;
    }

    /**
     * Analyzes image colors and creates color map.
     */
    protected void analyzePixels() {
        int len = pixels.length;
        int nPix = len / 3;
        indexedPixels = new byte[nPix];
        NeuQuant nq = new NeuQuant(pixels, len, sample);
        // initialize quantizer
        colorTab = nq.process(); // create reduced palette
        // convert map from BGR to RGB
        for (int i = 0; i < colorTab.length; i += 3) {
            byte temp = colorTab[i];
            colorTab[i] = colorTab[i + 2];
            colorTab[i + 2] = temp;
            usedEntry[i / 3] = false;
        }

        // map image pixels to new palette
        int k = 0;
        for (int i = 0; i < nPix; i++) {
            int index = nq.map(pixels[k++] & 0xff, pixels[k++] & 0xff, pixels[k++] & 0xff , transparent != -1);
            usedEntry[index] = true;
            indexedPixels[i] = (byte) index;
        }

        pixels = null;
        colorDepth = 8;
        palSize = 7;

        // get closest match to transparent color if specified
        if (transparent != -1) {
            transIndex = findClosest(transparent);
        }
    }

    /**
     * Returns index of palette color closest to c
     */
    protected int findClosest(int c) {
        if (colorTab == null)
            return -1;
        int r = (c >> 16) & 0xff;
        int g = (c >> 8) & 0xff;
        int b = (c >> 0) & 0xff;
        int minpos = 0;
        int len = colorTab.length;

        //RGB值严格相等才显示透明
        for (int i = 0; i < len; ) {
            int dr = r - (colorTab[i++] & 0xff);
            int dg = g - (colorTab[i++] & 0xff);
            int db = b - (colorTab[i] & 0xff);
            int d = dr * dr + dg * dg + db * db;
            int index = i / 3;
            if(usedEntry[index]
                    && d == 0){
                minpos = index;
            }
            i++;
        }
        return minpos;
    }

    /**
     * Extracts image pixels into byte array "pixels"
     */
    protected void getImagePixels() {
        int w = image.getWidth();
        int h = image.getHeight();
        if ((w != width) || (h != height)) {
            // create new image with right size/format
            Bitmap temp = Bitmap.createBitmap(width, height, Config.ARGB_4444);
            Canvas g = new Canvas(temp);
            g.drawBitmap(image, 0, 0, new Paint());
            image = temp;
        }
        int[] data = getImageData(image);
        pixels = new byte[data.length * 3];

        for (int i = 0; i < data.length; i++) {
            int td = data[i];
            if(td >> 24 != 0) {//去掉透明像素,这里实际上透明像素被赋值为0了
                float r = ((td >> 16) & 0xff);
                float g = ((td >> 8) & 0xff);
                float b = ((td) & 0xff);

                //由于设置了黑色为透明，所以图片里面原本的黑色都需要改为其他颜色
                if (r == 0 && g == 0 && b == 0) {
                    int tind = i * 3;
                    pixels[tind++] = (byte) (1);
                    pixels[tind++] = (byte) (1);
                    pixels[tind] = (byte) (1);
                } else {
                    int tind = i * 3;
                    pixels[tind++] = (byte) (b);
                    pixels[tind++] = (byte) (g);
                    pixels[tind] = (byte) (r);
                }
            }
        }
    }


    protected int[] getImageData(Bitmap img) {
        int w = img.getWidth();
        int h = img.getHeight();

        int[] data = new int[w * h];
        img.getPixels(data, 0, w, 0, 0, w, h);
        return data;
    }

    /**
     * Writes Graphic Control Extension
     */
    protected void writeGraphicCtrlExt() throws IOException {
        out.write(0x21); // extension introducer
        out.write(0xf9); // GCE label
        out.write(4); // data block size
        int transp, disp;
        if (transparent == -1) {
            transp = 0;
            disp = 0; // dispose = no action
        } else {
            transp = 1;
            disp = 2; // force clear if using transparent color
        }
        if (dispose >= 0) {
            disp = dispose & 7; // user override
        }
        disp <<= 2;

        // packed fields
        out.write(0 | // 1:3 reserved
                disp | // 4:6 disposal
                0 | // 7 user input - 0 = none
                transp); // 8 transparency flag

        writeShort(delay); // delay x 1/100 sec
        out.write(transIndex); // transparent color index
        out.write(0); // block terminator
    }

    /**
     * Writes Image Descriptor
     */
    protected void writeImageDesc() throws IOException {
        out.write(0x2c); // image separator
        writeShort(x); // image position x,y = 0,0
        writeShort(y);
        writeShort(width); // image size
        writeShort(height);
        // packed fields
        if (firstFrame) {
            // no LCT - GCT is used for first (or only) frame
            out.write(0);
        } else {
            // specify normal LCT
            out.write(0x80 | // 1 local color table 1=yes
                    0 | // 2 interlace - 0=no
                    0 | // 3 sorted - 0=no
                    0 | // 4-5 reserved
                    palSize); // 6-8 size of color table
        }
    }

    /**
     * Writes Logical Screen Descriptor
     */
    protected void writeLSD() throws IOException {
        // logical screen size
        writeShort(width);
        writeShort(height);
        // packed fields
        out.write((0x80 | // 1 : global color table flag = 1 (gct used)
                0x70 | // 2-4 : color resolution = 7
                0x00 | // 5 : gct sort flag = 0
                palSize)); // 6-8 : gct size

        out.write(0); // background color index
        out.write(0); // pixel aspect ratio - assume 1:1
    }

    /**
     * Writes Netscape application extension to define repeat count.
     */
    protected void writeNetscapeExt() throws IOException {
        out.write(0x21); // extension introducer
        out.write(0xff); // app extension label
        out.write(11); // block size
        writeString("NETSCAPE" + "2.0"); // app id + auth code
        out.write(3); // sub-block size
        out.write(1); // loop sub-block id
        writeShort(repeat); // loop count (extra iterations, 0=repeat forever)
        out.write(0); // block terminator
    }

    /**
     * Writes color table
     */
    protected void writePalette() throws IOException {
        out.write(colorTab, 0, colorTab.length);
        int n = (3 * 256) - colorTab.length;
        for (int i = 0; i < n; i++) {
            out.write(0);
        }
    }

    /**
     * Encodes and writes pixel data
     */
    protected void writePixels() throws IOException {
        LZWEncoder encoder = new LZWEncoder(width, height, indexedPixels, colorDepth);
        encoder.encode(out);
    }

    /**
     * Write 16-bit value to output stream, LSB first
     */
    protected void writeShort(int value) throws IOException {
        out.write(value & 0xff);
        out.write((value >> 8) & 0xff);
    }

    /**
     * Writes string to output stream
     */
    protected void writeString(String s) throws IOException {
        for (int i = 0; i < s.length(); i++) {
            out.write((byte) s.charAt(i));
        }
    }
}

/*
 * NeuQuant Neural-Net Quantization Algorithm
 * ------------------------------------------
 *
 * Copyright (c) 1994 Anthony Dekker
 *
 * NEUQUANT Neural-Net quantization algorithm by Anthony Dekker, 1994. See
 * "Kohonen neural networks for optimal colour quantization" in "Network:
 * Computation in Neural Systems" Vol. 5 (1994) pp 351-367. for a discussion of
 * the algorithm.
 *
 * Any party obtaining a copy of these files from the author, directly or
 * indirectly, is granted, free of charge, a full and unrestricted irrevocable,
 * world-wide, paid up, royalty-free, nonexclusive right and license to deal in
 * this software and documentation files (the "Software"), including without
 * limitation the rights to use, copy, modify, merge, publish, distribute,
 * sublicense, and/or sell copies of the Software, and to permit persons who
 * receive copies from any such party to do so, with the only requirement being
 * that this copyright notice remain intact.
 */

//	 Ported to Java 12/00 K Weiner
//class NeuQuant {
//
//    protected static final int netsize = 256; /* number of colours used */
//
//    /* four primes near 500 - assume no image has a length so large */
//    /* that it is divisible by all four primes */
//    protected static final int prime1 = 499;
//
//    protected static final int prime2 = 491;
//
//    protected static final int prime3 = 487;
//
//    protected static final int prime4 = 503;
//
//    protected static final int minpicturebytes = (3 * prime4);
//
//    /* minimum size for input image */
//
//    /*
//     * Program Skeleton ---------------- [select samplefac in range 1..30] [read
//     * image from input file] pic = (unsigned char*) malloc(3*width*height);
//     * initnet(pic,3*width*height,samplefac); learn(); unbiasnet(); [write output
//     * image header, using writecolourmap(f)] inxbuild(); write output image using
//     * inxsearch(b,g,r)
//     */
//
//    /*
//     * Network Definitions -------------------
//     */
//
//    protected static final int maxnetpos = (netsize - 1);
//
//    protected static final int netbiasshift = 4; /* bias for colour values */
//
//    protected static final int ncycles = 100; /* no. of learning cycles */
//
//    /* defs for freq and bias */
//    protected static final int intbiasshift = 16; /* bias for fractions */
//
//    protected static final int intbias = (((int) 1) << intbiasshift);
//
//    protected static final int gammashift = 10; /* gamma = 1024 */
//
//    protected static final int gamma = (((int) 1) << gammashift);
//
//    protected static final int betashift = 10;
//
//    protected static final int beta = (intbias >> betashift); /* beta = 1/1024 */
//
//    protected static final int betagamma = (intbias << (gammashift - betashift));
//
//    /* defs for decreasing radius factor */
//    protected static final int initrad = (netsize >> 3); /*
//     * for 256 cols, radius
//     * starts
//     */
//
//    protected static final int radiusbiasshift = 6; /* at 32.0 biased by 6 bits */
//
//    protected static final int radiusbias = (((int) 1) << radiusbiasshift);
//
//    protected static final int initradius = (initrad * radiusbias); /*
//     * and
//     * decreases
//     * by a
//     */
//
//    protected static final int radiusdec = 30; /* factor of 1/30 each cycle */
//
//    /* defs for decreasing alpha factor */
//    protected static final int alphabiasshift = 10; /* alpha starts at 1.0 */
//
//    protected static final int initalpha = (((int) 1) << alphabiasshift);
//
//    protected int alphadec; /* biased by 10 bits */
//
//    /* radbias and alpharadbias used for radpower calculation */
//    protected static final int radbiasshift = 8;
//
//    protected static final int radbias = (((int) 1) << radbiasshift);
//
//    protected static final int alpharadbshift = (alphabiasshift + radbiasshift);
//
//    protected static final int alpharadbias = (((int) 1) << alpharadbshift);
//
//    /*
//     * Types and Global Variables --------------------------
//     */
//
//    protected byte[] thepicture; /* the input image itself */
//
//    protected int lengthcount; /* lengthcount = H*W*3 */
//
//    protected int samplefac; /* sampling factor 1..30 */
//
//    // typedef int pixel[4]; /* BGRc */
//    protected int[][] network; /* the network itself - [netsize][4] */
//
//    protected int[] netindex = new int[256];
//
//    /* for network lookup - really 256 */
//
//    protected int[] bias = new int[netsize];
//
//    /* bias and freq arrays for learning */
//    protected int[] freq = new int[netsize];
//
//    protected int[] radpower = new int[initrad];
//
//    /* radpower for precomputation */
//
//    /*
//     * Initialise network in range (0,0,0) to (255,255,255) and set parameters
//     * -----------------------------------------------------------------------
//     */
//    public NeuQuant(byte[] thepic, int len, int sample) {
//
//        int i;
//        int[] p;
//
//        thepicture = thepic;
//        lengthcount = len;
//        samplefac = sample;
//
//        network = new int[netsize][];
//        for (i = 0; i < netsize; i++) {
//            network[i] = new int[4];
//            p = network[i];
//            p[0] = p[1] = p[2] = (i << (netbiasshift + 8)) / netsize;
//            freq[i] = intbias / netsize; /* 1/netsize */
//            bias[i] = 0;
//        }
//    }
//
//    public byte[] colorMap() {
//        byte[] map = new byte[3 * netsize];
//        int[] index = new int[netsize];
//        for (int i = 0; i < netsize; i++)
//            index[network[i][3]] = i;
//        int k = 0;
//        for (int i = 0; i < netsize; i++) {
//            int j = index[i];
//            map[k++] = (byte) (network[j][0]);
//            map[k++] = (byte) (network[j][1]);
//            map[k++] = (byte) (network[j][2]);
//        }
//        return map;
//    }
//
//    /*
//     * Insertion sort of network and building of netindex[0..255] (to do after
//     * unbias)
//     * -------------------------------------------------------------------------------
//     */
//    public void inxbuild() {
//
//        int i, j, smallpos, smallval;
//        int[] p;
//        int[] q;
//        int previouscol, startpos;
//
//        previouscol = 0;
//        startpos = 0;
//        for (i = 0; i < netsize; i++) {
//            p = network[i];
//            smallpos = i;
//            smallval = p[1]; /* index on g */
//            /* find smallest in i..netsize-1 */
//            for (j = i + 1; j < netsize; j++) {
//                q = network[j];
//                if (q[1] < smallval) { /* index on g */
//                    smallpos = j;
//                    smallval = q[1]; /* index on g */
//                }
//            }
//            q = network[smallpos];
//            /* swap p (i) and q (smallpos) entries */
//            if (i != smallpos) {
//                j = q[0];
//                q[0] = p[0];
//                p[0] = j;
//                j = q[1];
//                q[1] = p[1];
//                p[1] = j;
//                j = q[2];
//                q[2] = p[2];
//                p[2] = j;
//                j = q[3];
//                q[3] = p[3];
//                p[3] = j;
//            }
//            /* smallval entry is now in position i */
//            if (smallval != previouscol) {
//                netindex[previouscol] = (startpos + i) >> 1;
//                for (j = previouscol + 1; j < smallval; j++)
//                    netindex[j] = i;
//                previouscol = smallval;
//                startpos = i;
//            }
//        }
//        netindex[previouscol] = (startpos + maxnetpos) >> 1;
//        for (j = previouscol + 1; j < 256; j++)
//            netindex[j] = maxnetpos; /* really 256 */
//    }
//
//    /*
//     * Main Learning Loop ------------------
//     */
//    public void learn() {
//
//        int i, j, b, g, r;
//        int radius, rad, alpha, step, delta, samplepixels;
//        byte[] p;
//        int pix, lim;
//
//        if (lengthcount < minpicturebytes)
//            samplefac = 1;
//        alphadec = 30 + ((samplefac - 1) / 3);
//        p = thepicture;
//        pix = 0;
//        lim = lengthcount;
//        samplepixels = lengthcount / (3 * samplefac);
//        delta = samplepixels / ncycles;
//        alpha = initalpha;
//        radius = initradius;
//
//        rad = radius >> radiusbiasshift;
//        if (rad <= 1)
//            rad = 0;
//        for (i = 0; i < rad; i++)
//            radpower[i] = alpha * (((rad * rad - i * i) * radbias) / (rad * rad));
//
//        // fprintf(stderr,"beginning 1D learning: initial radius=%d\n", rad);
//
//        if (lengthcount < minpicturebytes)
//            step = 3;
//        else if ((lengthcount % prime1) != 0)
//            step = 3 * prime1;
//        else {
//            if ((lengthcount % prime2) != 0)
//                step = 3 * prime2;
//            else {
//                if ((lengthcount % prime3) != 0)
//                    step = 3 * prime3;
//                else
//                    step = 3 * prime4;
//            }
//        }
//
//        i = 0;
//        while (i < samplepixels) {
//            b = (p[pix + 0] & 0xff) << netbiasshift;
//            g = (p[pix + 1] & 0xff) << netbiasshift;
//            r = (p[pix + 2] & 0xff) << netbiasshift;
//            j = contest(b, g, r);
//
//            altersingle(alpha, j, b, g, r);
//            if (rad != 0)
//                alterneigh(rad, j, b, g, r); /* alter neighbours */
//
//            pix += step;
//            if (pix >= lim)
//                pix -= lengthcount;
//
//            i++;
//            if (delta == 0)
//                delta = 1;
//            if (i % delta == 0) {
//                alpha -= alpha / alphadec;
//                radius -= radius / radiusdec;
//                rad = radius >> radiusbiasshift;
//                if (rad <= 1)
//                    rad = 0;
//                for (j = 0; j < rad; j++)
//                    radpower[j] = alpha * (((rad * rad - j * j) * radbias) / (rad * rad));
//            }
//        }
//        // fprintf(stderr,"finished 1D learning: final alpha=%f
//        // !\n",((float)alpha)/initalpha);
//    }
//
//    /*
//     * Search for BGR values 0..255 (after net is unbiased) and return colour
//     * index
//     * ----------------------------------------------------------------------------
//     */
//    public int map(int b, int g, int r) {
//
//        int i, j, dist, a, bestd;
//        int[] p;
//        int best;
//
//        bestd = 1000; /* biggest possible dist is 256*3 */
//        best = -1;
//        i = netindex[g]; /* index on g */
//        j = i - 1; /* start at netindex[g] and work outwards */
//
//        while ((i < netsize) || (j >= 0)) {
//            if (i < netsize) {
//                p = network[i];
//                dist = p[1] - g; /* inx key */
//                if (dist >= bestd)
//                    i = netsize; /* stop iter */
//                else {
//                    i++;
//                    if (dist < 0)
//                        dist = -dist;
//                    a = p[0] - b;
//                    if (a < 0)
//                        a = -a;
//                    dist += a;
//                    if (dist < bestd) {
//                        a = p[2] - r;
//                        if (a < 0)
//                            a = -a;
//                        dist += a;
//                        if (dist < bestd) {
//                            bestd = dist;
//                            best = p[3];
//                        }
//                    }
//                }
//            }
//            if (j >= 0) {
//                p = network[j];
//                dist = g - p[1]; /* inx key - reverse dif */
//                if (dist >= bestd)
//                    j = -1; /* stop iter */
//                else {
//                    j--;
//                    if (dist < 0)
//                        dist = -dist;
//                    a = p[0] - b;
//                    if (a < 0)
//                        a = -a;
//                    dist += a;
//                    if (dist < bestd) {
//                        a = p[2] - r;
//                        if (a < 0)
//                            a = -a;
//                        dist += a;
//                        if (dist < bestd) {
//                            bestd = dist;
//                            best = p[3];
//                        }
//                    }
//                }
//            }
//        }
//        return (best);
//    }
//
//    public byte[] process() {
//        learn();
//        unbiasnet();
//        inxbuild();
//        return colorMap();
//    }
//
//    /*
//     * Unbias network to give byte values 0..255 and record position i to prepare
//     * for sort
//     * -----------------------------------------------------------------------------------
//     */
//    public void unbiasnet() {
//
//        int i;
//
//        for (i = 0; i < netsize; i++) {
//            network[i][0] >>= netbiasshift;
//            network[i][1] >>= netbiasshift;
//            network[i][2] >>= netbiasshift;
//            network[i][3] = i; /* record colour no */
//        }
//    }
//
//    /*
//     * Move adjacent neurons by precomputed alpha*(1-((i-j)^2/[r]^2)) in
//     * radpower[|i-j|]
//     * ---------------------------------------------------------------------------------
//     */
//    protected void alterneigh(int rad, int i, int b, int g, int r) {
//
//        int j, k, lo, hi, a, m;
//        int[] p;
//
//        lo = i - rad;
//        if (lo < -1)
//            lo = -1;
//        hi = i + rad;
//        if (hi > netsize)
//            hi = netsize;
//
//        j = i + 1;
//        k = i - 1;
//        m = 1;
//        while ((j < hi) || (k > lo)) {
//            a = radpower[m++];
//            if (j < hi) {
//                p = network[j++];
//                try {
//                    p[0] -= (a * (p[0] - b)) / alpharadbias;
//                    p[1] -= (a * (p[1] - g)) / alpharadbias;
//                    p[2] -= (a * (p[2] - r)) / alpharadbias;
//                } catch (Exception e) {
//                } // prevents 1.3 miscompilation
//            }
//            if (k > lo) {
//                p = network[k--];
//                try {
//                    p[0] -= (a * (p[0] - b)) / alpharadbias;
//                    p[1] -= (a * (p[1] - g)) / alpharadbias;
//                    p[2] -= (a * (p[2] - r)) / alpharadbias;
//                } catch (Exception e) {
//                }
//            }
//        }
//    }
//
//    /*
//     * Move neuron i towards biased (b,g,r) by factor alpha
//     * ----------------------------------------------------
//     */
//    protected void altersingle(int alpha, int i, int b, int g, int r) {
//
//        /* alter hit neuron */
//        int[] n = network[i];
//        n[0] -= (alpha * (n[0] - b)) / initalpha;
//        n[1] -= (alpha * (n[1] - g)) / initalpha;
//        n[2] -= (alpha * (n[2] - r)) / initalpha;
//    }
//
//    /*
//     * Search for biased BGR values ----------------------------
//     */
//    protected int contest(int b, int g, int r) {
//
//        /* finds closest neuron (min dist) and updates freq */
//        /* finds best neuron (min dist-bias) and returns position */
//        /* for frequently chosen neurons, freq[i] is high and bias[i] is negative */
//        /* bias[i] = gamma*((1/netsize)-freq[i]) */
//
//        int i, dist, a, biasdist, betafreq;
//        int bestpos, bestbiaspos, bestd, bestbiasd;
//        int[] n;
//
//        bestd = ~(((int) 1) << 31);
//        bestbiasd = bestd;
//        bestpos = -1;
//        bestbiaspos = bestpos;
//
//        for (i = 0; i < netsize; i++) {
//            n = network[i];
//            dist = n[0] - b;
//            if (dist < 0)
//                dist = -dist;
//            a = n[1] - g;
//            if (a < 0)
//                a = -a;
//            dist += a;
//            a = n[2] - r;
//            if (a < 0)
//                a = -a;
//            dist += a;
//            if (dist < bestd) {
//                bestd = dist;
//                bestpos = i;
//            }
//            biasdist = dist - ((bias[i]) >> (intbiasshift - netbiasshift));
//            if (biasdist < bestbiasd) {
//                bestbiasd = biasdist;
//                bestbiaspos = i;
//            }
//            betafreq = (freq[i] >> betashift);
//            freq[i] -= betafreq;
//            bias[i] += (betafreq << gammashift);
//        }
//        freq[bestpos] += beta;
//        bias[bestpos] -= betagamma;
//        return (bestbiaspos);
//    }
//}

//	 ==============================================================================
//	 Adapted from Jef Poskanzer's Java port by way of J. M. G. Elliott.
//	 K Weiner 12/00

//class LZWEncoder {
//
//    private static final int EOF = -1;
//
//    private int imgW, imgH;
//
//    private byte[] pixAry;
//
//    private int initCodeSize;
//
//    private int remaining;
//
//    private int curPixel;
//
//    // GIFCOMPR.C - GIF Image compression routines
//    //
//    // Lempel-Ziv compression based on 'compress'. GIF modifications by
//    // David Rowley (mgardi@watdcsu.waterloo.edu)
//
//    // General DEFINEs
//
//    static final int BITS = 12;
//
//    static final int HSIZE = 5003; // 80% occupancy
//
//    // GIF Image compression - modified 'compress'
//    //
//    // Based on: compress.c - File compression ala IEEE Computer, June 1984.
//    //
//    // By Authors: Spencer W. Thomas (decvax!harpo!utah-cs!utah-gr!thomas)
//    // Jim McKie (decvax!mcvax!jim)
//    // Steve Davies (decvax!vax135!petsd!peora!srd)
//    // Ken Turkowski (decvax!decwrl!turtlevax!ken)
//    // James A. Woods (decvax!ihnp4!ames!jaw)
//    // Joe Orost (decvax!vax135!petsd!joe)
//
//    int n_bits; // number of bits/code
//
//    int maxbits = BITS; // user settable max # bits/code
//
//    int maxcode; // maximum code, given n_bits
//
//    int maxmaxcode = 1 << BITS; // should NEVER generate this code
//
//    int[] htab = new int[HSIZE];
//
//    int[] codetab = new int[HSIZE];
//
//    int hsize = HSIZE; // for dynamic table sizing
//
//    int free_ent = 0; // first unused entry
//
//    // block compression parameters -- after all codes are used up,
//    // and compression rate changes, start over.
//    boolean clear_flg = false;
//
//    // Algorithm: use open addressing double hashing (no chaining) on the
//    // prefix code / next character combination. We do a variant of Knuth's
//    // algorithm D (vol. 3, sec. 6.4) along with G. Knott's relatively-prime
//    // secondary probe. Here, the modular division first probe is gives way
//    // to a faster exclusive-or manipulation. Also do block compression with
//    // an adaptive reset, whereby the code table is cleared when the compression
//    // ratio decreases, but after the table fills. The variable-length output
//    // codes are re-sized at this point, and a special CLEAR code is generated
//    // for the decompressor. Late addition: construct the table according to
//    // file size for noticeable speed improvement on small files. Please direct
//    // questions about this implementation to ames!jaw.
//
//    int g_init_bits;
//
//    int ClearCode;
//
//    int EOFCode;
//
//    // output
//    //
//    // Output the given code.
//    // Inputs:
//    // code: A n_bits-bit integer. If == -1, then EOF. This assumes
//    // that n_bits =< wordsize - 1.
//    // Outputs:
//    // Outputs code to the file.
//    // Assumptions:
//    // Chars are 8 bits long.
//    // Algorithm:
//    // Maintain a BITS character long buffer (so that 8 codes will
//    // fit in it exactly). Use the VAX insv instruction to insert each
//    // code in turn. When the buffer fills up empty it and start over.
//
//    int cur_accum = 0;
//
//    int cur_bits = 0;
//
//    int masks[] = {0x0000, 0x0001, 0x0003, 0x0007, 0x000F, 0x001F, 0x003F, 0x007F, 0x00FF, 0x01FF,
//            0x03FF, 0x07FF, 0x0FFF, 0x1FFF, 0x3FFF, 0x7FFF, 0xFFFF};
//
//    // Number of characters so far in this 'packet'
//    int a_count;
//
//    // Define the storage for the packet accumulator
//    byte[] accum = new byte[256];
//
//    // ----------------------------------------------------------------------------
//    LZWEncoder(int width, int height, byte[] pixels, int color_depth) {
//        imgW = width;
//        imgH = height;
//        pixAry = pixels;
//        initCodeSize = Math.max(2, color_depth);
//    }
//
//    // Add a character to the end of the current packet, and if it is 254
//    // characters, flush the packet to disk.
//    void char_out(byte c, OutputStream outs) throws IOException {
//        accum[a_count++] = c;
//        if (a_count >= 254)
//            flush_char(outs);
//    }
//
//    // Clear out the hash table
//
//    // table clear for block compress
//    void cl_block(OutputStream outs) throws IOException {
//        cl_hash(hsize);
//        free_ent = ClearCode + 2;
//        clear_flg = true;
//
//        output(ClearCode, outs);
//    }
//
//    // reset code table
//    void cl_hash(int hsize) {
//        for (int i = 0; i < hsize; ++i)
//            htab[i] = -1;
//    }
//
//    void compress(int init_bits, OutputStream outs) throws IOException {
//        int fcode;
//        int i /* = 0 */;
//        int c;
//        int ent;
//        int disp;
//        int hsize_reg;
//        int hshift;
//
//        // Set up the globals: g_init_bits - initial number of bits
//        g_init_bits = init_bits;
//
//        // Set up the necessary values
//        clear_flg = false;
//        n_bits = g_init_bits;
//        maxcode = MAXCODE(n_bits);
//
//        ClearCode = 1 << (init_bits - 1);
//        EOFCode = ClearCode + 1;
//        free_ent = ClearCode + 2;
//
//        a_count = 0; // clear packet
//
//        ent = nextPixel();
//
//        hshift = 0;
//        for (fcode = hsize; fcode < 65536; fcode *= 2)
//            ++hshift;
//        hshift = 8 - hshift; // set hash code range bound
//
//        hsize_reg = hsize;
//        cl_hash(hsize_reg); // clear hash table
//
//        output(ClearCode, outs);
//
//        outer_loop:
//        while ((c = nextPixel()) != EOF) {
//            fcode = (c << maxbits) + ent;
//            i = (c << hshift) ^ ent; // xor hashing
//
//            if (htab[i] == fcode) {
//                ent = codetab[i];
//                continue;
//            } else if (htab[i] >= 0) // non-empty slot
//            {
//                disp = hsize_reg - i; // secondary hash (after G. Knott)
//                if (i == 0)
//                    disp = 1;
//                do {
//                    if ((i -= disp) < 0)
//                        i += hsize_reg;
//
//                    if (htab[i] == fcode) {
//                        ent = codetab[i];
//                        continue outer_loop;
//                    }
//                } while (htab[i] >= 0);
//            }
//            output(ent, outs);
//            ent = c;
//            if (free_ent < maxmaxcode) {
//                codetab[i] = free_ent++; // code -> hashtable
//                htab[i] = fcode;
//            } else
//                cl_block(outs);
//        }
//        // Put out the final code.
//        output(ent, outs);
//        output(EOFCode, outs);
//    }
//
//    // ----------------------------------------------------------------------------
//    void encode(OutputStream os) throws IOException {
//        os.write(initCodeSize); // write "initial code size" byte
//
//        remaining = imgW * imgH; // reset navigation variables
//        curPixel = 0;
//
//        compress(initCodeSize + 1, os); // compress and write the pixel data
//
//        os.write(0); // write block terminator
//    }
//
//    // Flush the packet to disk, and reset the accumulator
//    void flush_char(OutputStream outs) throws IOException {
//        if (a_count > 0) {
//            outs.write(a_count);
//            outs.write(accum, 0, a_count);
//            a_count = 0;
//        }
//    }
//
//    final int MAXCODE(int n_bits) {
//        return (1 << n_bits) - 1;
//    }
//
//    // ----------------------------------------------------------------------------
//    // Return the next pixel from the image
//    // ----------------------------------------------------------------------------
//    private int nextPixel() {
//        if (remaining == 0)
//            return EOF;
//
//        --remaining;
//
//        byte pix = pixAry[curPixel++];
//
//        return pix & 0xff;
//    }
//
//    void output(int code, OutputStream outs) throws IOException {
//        cur_accum &= masks[cur_bits];
//
//        if (cur_bits > 0)
//            cur_accum |= (code << cur_bits);
//        else
//            cur_accum = code;
//
//        cur_bits += n_bits;
//
//        while (cur_bits >= 8) {
//            char_out((byte) (cur_accum & 0xff), outs);
//            cur_accum >>= 8;
//            cur_bits -= 8;
//        }
//
//        // If the next entry is going to be too big for the code size,
//        // then increase it, if possible.
//        if (free_ent > maxcode || clear_flg) {
//            if (clear_flg) {
//                maxcode = MAXCODE(n_bits = g_init_bits);
//                clear_flg = false;
//            } else {
//                ++n_bits;
//                if (n_bits == maxbits)
//                    maxcode = maxmaxcode;
//                else
//                    maxcode = MAXCODE(n_bits);
//            }
//        }
//
//        if (code == EOFCode) {
//            // At EOF, write the rest of the buffer.
//            while (cur_bits > 0) {
//                char_out((byte) (cur_accum & 0xff), outs);
//                cur_accum >>= 8;
//                cur_bits -= 8;
//            }
//
//            flush_char(outs);
//        }
//    }
//}