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- package com.softwhir.dealwithit;
- import java.io.IOException;
- import java.io.OutputStream;
- import android.graphics.Bitmap;
- import android.graphics.Bitmap.Config;
- import android.graphics.Canvas;
- import android.graphics.Paint;
- public class AnimatedGifEncoder {
- protected int width; // image size
- protected int height;
- protected int transparent = -1; // transparent color if given
- protected int transIndex; // transparent index in color table
- protected int repeat = -1; // no repeat
- protected int delay = 0; // frame delay (hundredths)
- protected boolean started = false; // ready to output frames
- protected OutputStream out;
- protected Bitmap image; // current frame
- 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 = false; // 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;
- }
- /**
- * 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) {
- 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) {
- if ((im == null) || !started) {
- return false;
- }
- boolean ok = true;
- try {
- if (!sizeSet) {
- // use first frame's size
- setSize(im.getWidth(), im.getHeight());
- }
- image = im;
- 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) {
- ok = false;
- }
- return ok;
- }
- /**
- * 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.
- * @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) {
- if (started && !firstFrame)
- return;
- width = w;
- height = h;
- if (width < 1)
- width = 320;
- if (height < 1)
- height = 240;
- sizeSet = true;
- }
- /**
- * 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) {
- 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);
- 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 dmin = 256 * 256 * 256;
- int len = colorTab.length;
- 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 < dmin)) {
- dmin = d;
- 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.RGB_565);
- 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];
- int tind = i * 3;
- pixels[tind++] = (byte) ((td >> 0) & 0xFF);
- pixels[tind++] = (byte) ((td >> 8) & 0xFF);
- pixels[tind] = (byte) ((td >> 16) & 0xFF);
- }
- }
- 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(0); // image position x,y = 0,0
- writeShort(0);
- 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);
- }
- }
- }
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