Java/2D Graphics GUI/GIF
Содержание
- 1 Animated Gif Encoder
- 2 AnimatedGifEncoder - Encodes a GIF file consisting of one or more frames
- 3 Class for converting images to GIF files
- 4 Converting GIF to PostScript
- 5 Decodes a GIF file into one or more frames
- 6 Get Gif Properties
- 7 Gif Encoder
- 8 Gif Encoder implements ImageConsumer
- 9 GIFEncoder is a class which takes an image and saves it to a stream using the GIF file format
- 10 Gif Encoder - writes out an image as a GIF.
- 11 Gif file Encoder
- 12 GIF Writer
- 13 Hide the mouse cursor: use a transparent GIF as the cursor
Animated Gif Encoder
<source lang="java"> import java.io.*; import java.awt.*; import java.awt.image.*; /**
* Class AnimatedGifEncoder - Encodes a GIF file consisting of one or more * frames. **
* Example: * AnimatedGifEncoder e = new AnimatedGifEncoder(); * e.start(outputFileName); * e.setDelay(1000); // 1 frame per sec * e.addFrame(image1); * e.addFrame(image2); * e.finish(); *
* * No copyright asserted on the source code of this class. May be used for any * purpose, however, refer to the Unisys LZW patent for restrictions on use of * the associated LZWEncoder class. Please forward any corrections to * kweiner@fmsware.ru. * * @author Kevin Weiner, FM Software * @version 1.03 November 2003 * */
public class AnimatedGifEncoder {
protected int width; // image size
protected int height;
protected Color transparent = null; // 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 BufferedImage 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 = Math.round(ms / 10.0f);
}
/**
* 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(Color 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 finish() flushes all frames. If
* setSize 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(BufferedImage 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
* setDelay(1000/fps).
*
* @param fps
* float frame rate (frames per second)
*/
public void setFrameRate(float fps) {
if (fps != 0f) {
delay = Math.round(100f / 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;
}
/**
* Initiates writing of a GIF file with the specified name.
*
* @param file
* String containing output file name.
* @return false if open or initial write failed.
*/
public boolean start(String file) {
boolean ok = true;
try {
out = new BufferedOutputStream(new FileOutputStream(file));
ok = start(out);
closeStream = true;
} 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 != null) {
transIndex = findClosest(transparent);
}
}
/**
* Returns index of palette color closest to c
*
*/
protected int findClosest(Color c) {
if (colorTab == null)
return -1;
int r = c.getRed();
int g = c.getGreen();
int b = c.getBlue();
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();
int type = image.getType();
if ((w != width) || (h != height) || (type != BufferedImage.TYPE_3BYTE_BGR)) {
// create new image with right size/format
BufferedImage temp = new BufferedImage(width, height, BufferedImage.TYPE_3BYTE_BGR);
Graphics2D g = temp.createGraphics();
g.drawImage(image, 0, 0, null);
image = temp;
}
pixels = ((DataBufferByte) image.getRaster().getDataBuffer()).getData();
}
/**
* 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 == null) {
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, j;
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);
}
}
}
</source>
AnimatedGifEncoder - Encodes a GIF file consisting of one or more frames
<source lang="java"> import java.awt.Color; import java.awt.Graphics2D; import java.awt.image.BufferedImage; import java.awt.image.DataBufferByte; import java.io.BufferedOutputStream; import java.io.FileOutputStream; import java.io.IOException; import java.io.OutputStream; /**
* Class AnimatedGifEncoder - Encodes a GIF file consisting of one or more * frames. **
* Example: * AnimatedGifEncoder e = new AnimatedGifEncoder(); * e.start(outputFileName); * e.setDelay(1000); // 1 frame per sec * e.addFrame(image1); * e.addFrame(image2); * e.finish(); *
* * No copyright asserted on the source code of this class. May be used for any * purpose, however, refer to the Unisys LZW patent for restrictions on use of * the associated LZWEncoder class. Please forward any corrections to * kweiner@fmsware.ru. * * @author Kevin Weiner, FM Software * @version 1.03 November 2003 * */
public class AnimatedGifEncoder {
protected int width; // image size
protected int height;
protected Color transparent = null; // 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 BufferedImage 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 = Math.round(ms / 10.0f);
}
/**
* 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(Color 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 finish() flushes all frames. If
* setSize 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(BufferedImage 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
* setDelay(1000/fps).
*
* @param fps
* float frame rate (frames per second)
*/
public void setFrameRate(float fps) {
if (fps != 0f) {
delay = Math.round(100f / 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;
}
/**
* Initiates writing of a GIF file with the specified name.
*
* @param file
* String containing output file name.
* @return false if open or initial write failed.
*/
public boolean start(String file) {
boolean ok = true;
try {
out = new BufferedOutputStream(new FileOutputStream(file));
ok = start(out);
closeStream = true;
} 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 != null) {
transIndex = findClosest(transparent);
}
}
/**
* Returns index of palette color closest to c
*
*/
protected int findClosest(Color c) {
if (colorTab == null)
return -1;
int r = c.getRed();
int g = c.getGreen();
int b = c.getBlue();
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();
int type = image.getType();
if ((w != width) || (h != height) || (type != BufferedImage.TYPE_3BYTE_BGR)) {
// create new image with right size/format
BufferedImage temp = new BufferedImage(width, height, BufferedImage.TYPE_3BYTE_BGR);
Graphics2D g = temp.createGraphics();
g.drawImage(image, 0, 0, null);
image = temp;
}
pixels = ((DataBufferByte) image.getRaster().getDataBuffer()).getData();
}
/**
* 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 == null) {
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));
}
}
} // // 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);
}
}
} /*
* 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() {
for (int 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);
}
}
</source>
Class for converting images to GIF files
<source lang="java"> /*
* (C) 2004 - Geotechnical Software Services * * This code is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This code is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this program; if not, write to the Free * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, * MA 02111-1307, USA. */
package no.geosoft.cc.io;
import java.io.*; import java.awt.*; import java.awt.image.*;
/**
* Class for converting images to GIF files. **
* Contribution: *
-
*
- Sverre H. Huseby (gifsave.c on which this is based) *
- Adam Doppelt (Initial Java port) *
- Greg Faron (Initial java port) *
* * @author */
public class GifEncoder {
private short imageWidth_, imageHeight_; private int nColors_; private byte[] pixels_ = null; private byte[] colors_ = null;
/**
* Constructing a GIF encoder.
*
* @param image The image to encode. The image must be
* completely loaded.
* @throws AWTException If memory is exhausted or image contains
* more than 256 colors.
*/
public GifEncoder (Image image)
throws AWTException
{
imageWidth_ = (short) image.getWidth (null);
imageHeight_ = (short) image.getHeight (null);
int values[] = new int[imageWidth_ * imageHeight_];
PixelGrabber grabber = new PixelGrabber (image, 0, 0,
imageWidth_, imageHeight_,
values, 0, imageWidth_);
try {
if (grabber.grabPixels() != true)
throw new AWTException("Grabber returned false: " + grabber.status());
}
catch (InterruptedException exception) {
}
byte[][] r = new byte[imageWidth_][imageHeight_];
byte[][] g = new byte[imageWidth_][imageHeight_];
byte[][] b = new byte[imageWidth_][imageHeight_];
int index = 0;
for (int y = 0; y < imageHeight_; y ++) {
for (int x = 0; x < imageWidth_; x ++, index ++) {
r[x][y] = (byte) ((values[index] >> 16) & 0xFF);
g[x][y] = (byte) ((values[index] >> 8) & 0xFF);
b[x][y] = (byte) ((values[index] >> 0) & 0xFF);
}
}
toIndexColor (r, g, b);
}
/**
* Create a GIF encoder. r[i][j] refers to the pixel at
* column i, row j.
*
* @param r Red intensity values.
* @param g Green intensity values.
* @param b Blue intensity values.
* @throws AWTException If memory is exhausted or image contains
* more than 256 colors.
*/
public GifEncoder (byte[][] r, byte[][] g, byte[][] b)
throws AWTException
{
imageWidth_ = (short) (r.length);
imageHeight_ = (short) (r[0].length);
toIndexColor(r, g, b);
}
/**
* Write image to GIF file.
*
* @param image Image to write.
* @param file File to erite to.
*/
public static void writeFile (Image image, File file)
throws AWTException, IOException
{
GifEncoder gifEncoder = new GifEncoder (image);
gifEncoder.write (new FileOutputStream (file));
}
/**
* Write AWT/Swing component to GIF file.
*
* @param image Image to write.
* @param file File to erite to.
*/
public static void writeFile (Component component, File file)
throws AWTException, IOException
{
Image image = component.createImage (component.getWidth(),
component.getHeight());
Graphics graphics = image.getGraphics();
component.printAll (graphics);
GifEncoder.writeFile (image, file);
}
/**
* Writes the image out to a stream in GIF format.
* This will be a single GIF87a image, non-interlaced, with no
* background color.
*
* @param stream The stream to which to output.
* @throws IOException Thrown if a write operation fails.
*/
public void write (OutputStream stream)
throws IOException
{
writeString (stream, "GIF87a");
writeScreenDescriptor (stream);
stream.write (colors_, 0, colors_.length);
writeImageDescriptor (stream, imageWidth_, imageHeight_, ",");
byte codeSize = bitsNeeded (nColors_);
if (codeSize == 1) codeSize++;
stream.write (codeSize);
writeLzwCompressed (stream, codeSize, pixels_);
stream.write(0);
writeImageDescriptor (stream, (short) 0, (short) 0, ";");
stream.flush();
stream.close();
}
/**
* Converts rgb desrcription of image to colour
* number description used by GIF.
*
* @param r Red array of pixels.
* @param g Green array of pixels.
* @param b Blue array of pixels.
* @throws AWTException
* Thrown if too many different colours in image.
*/
private void toIndexColor (byte[][] r, byte[][] g, byte[][] b)
throws AWTException
{
pixels_ = new byte[imageWidth_ * imageHeight_];
colors_ = new byte[256 * 3];
int colornum = 0;
for (int x = 0; x < imageWidth_; x++) {
for (int y = 0; y < imageHeight_; y++ ) {
int search;
for (search = 0; search < colornum; search ++ ) {
if (colors_[search * 3 + 0] == r[x][y] &&
colors_[search * 3 + 1] == g[x][y] &&
colors_[search * 3 + 2] == b[x][y]) {
break;
}
}
if (search > 255)
throw new AWTException("Too many colors.");
// Row major order y=row x=col
pixels_[y * imageWidth_ + x] = (byte) search;
if (search == colornum) {
colors_[search * 3 + 0] = r[x][y]; // [col][row]
colors_[search * 3 + 1] = g[x][y];
colors_[search * 3 + 2] = b[x][y];
colornum++;
}
}
}
nColors_ = 1 << bitsNeeded (colornum);
byte copy[] = new byte[nColors_ * 3];
System.arraycopy (colors_, 0, copy, 0, nColors_ * 3);
colors_ = copy;
}
private byte bitsNeeded (int n)
{
if (n-- == 0) return 0;
byte nBitsNeeded = 1;
while ((n >>= 1) != 0)
nBitsNeeded++;
return nBitsNeeded;
}
private void writeWord (OutputStream stream, short w)
throws IOException
{
stream.write (w & 0xFF);
stream.write ((w >> 8) & 0xFF);
}
private void writeString (OutputStream stream, String string)
throws IOException
{
for (int i = 0; i < string.length(); i ++ )
stream.write ((byte) (string.charAt (i)));
}
private void writeScreenDescriptor (OutputStream stream)
throws IOException
{
writeWord (stream, imageWidth_);
writeWord (stream, imageHeight_);
byte flag = 0;
// Global color table size
byte globalColorTableSize = (byte) (bitsNeeded (nColors_) - 1);
flag |= globalColorTableSize & 7;
// Global color table flag
byte globalColorTableFlag = 1;
flag |= (globalColorTableFlag & 1) << 7;
// Sort flag
byte sortFlag = 0;
flag |= (sortFlag & 1) << 3;
// Color resolution
byte colorResolution = 7;
flag |= (colorResolution & 7) << 4;
byte backgroundColorIndex = 0;
byte pixelAspectRatio = 0;
stream.write (flag);
stream.write (backgroundColorIndex);
stream.write (pixelAspectRatio);
}
private void writeImageDescriptor (OutputStream stream,
short width, short height, char separator)
throws IOException
{
stream.write (separator);
short leftPosition = 0;
short topPosition = 0;
writeWord (stream, leftPosition);
writeWord (stream, topPosition);
writeWord (stream, width);
writeWord (stream, height);
byte flag = 0;
// Local color table size
byte localColorTableSize = 0;
flag |= (localColorTableSize & 7);
// Reserved
byte reserved = 0;
flag |= (reserved & 3) << 3;
// Sort flag
byte sortFlag = 0;
flag |= (sortFlag & 1) << 5;
// Interlace flag
byte interlaceFlag = 0;
flag |= (interlaceFlag & 1) << 6;
// Local color table flag
byte localColorTableFlag = 0;
flag |= (localColorTableFlag & 1) << 7;
stream.write (flag);
}
private void writeLzwCompressed (OutputStream stream, int codeSize,
byte toCompress[])
throws IOException
{
byte c;
short index;
int clearcode, endofinfo, numbits, limit, errcode;
short prefix = (short) 0xFFFF;
BitFile bitFile = new BitFile (stream);
LzwStringTable strings = new LzwStringTable();
clearcode = 1 << codeSize;
endofinfo = clearcode + 1;
numbits = codeSize + 1;
limit = (1 << numbits) - 1;
strings.clearTable (codeSize);
bitFile.writeBits(clearcode, numbits);
for ( int loop = 0; loop < toCompress.length; loop ++ ) {
c = toCompress[loop];
if ( (index = strings.findCharString(prefix, c)) != -1 )
prefix = index;
else {
bitFile.writeBits(prefix, numbits);
if ( strings.addCharString(prefix, c) > limit ) {
if ( ++ numbits > 12 ) {
bitFile.writeBits(clearcode, numbits - 1);
strings.clearTable (codeSize);
numbits = codeSize + 1;
}
limit = (1 << numbits) - 1;
}
prefix = (short) ((short) c & 0xFF);
}
}
if ( prefix != -1 )
bitFile.writeBits(prefix, numbits);
bitFile.writeBits(endofinfo, numbits);
bitFile.flush();
}
/**
* Used to compress the image by looking for repeating
* elements.
*/
private class LzwStringTable
{
private final static int RES_CODES = 2;
private final static short HASH_FREE = (short) 0xFFFF;
private final static short NEXT_FIRST = (short) 0xFFFF;
private final static int MAXBITS = 12;
private final static int MAXSTR = (1 << MAXBITS);
private final static short HASHSIZE = 9973;
private final static short HASHSTEP = 2039;
private byte strChr_[];
private short strNxt_[];
private short strHsh_[];
private short nStrings_;
LzwStringTable()
{
strChr_ = new byte[MAXSTR];
strNxt_ = new short[MAXSTR];
strHsh_ = new short[HASHSIZE];
}
int addCharString (short index, byte b)
{
int hshidx;
if ( nStrings_ >= MAXSTR )
return 0xFFFF;
hshidx = hash (index, b);
while ( strHsh_[hshidx] != HASH_FREE )
hshidx = (hshidx + HASHSTEP) % HASHSIZE;
strHsh_[hshidx] = nStrings_;
strChr_[nStrings_] = b;
strNxt_[nStrings_] = (index != HASH_FREE)?index:NEXT_FIRST;
return nStrings_++;
}
short findCharString(short index, byte b)
{
int hshidx, nxtidx;
if ( index == HASH_FREE )
return b;
hshidx = hash (index, b);
while ( (nxtidx = strHsh_[hshidx]) != HASH_FREE ) {
if ( strNxt_[nxtidx] == index && strChr_[nxtidx] == b )
return(short) nxtidx;
hshidx = (hshidx + HASHSTEP) % HASHSIZE;
}
return(short) 0xFFFF;
}
void clearTable (int codesize)
{
nStrings_ = 0;
for ( int q = 0; q < HASHSIZE; q ++ )
strHsh_[q] = HASH_FREE;
int w = (1 << codesize) + RES_CODES;
for ( int q = 0; q < w; q ++ )
this.addCharString((short) 0xFFFF, (byte) q);
}
int hash (short index, byte lastbyte)
{
return ((int)((short) (lastbyte << 8) ^ index) & 0xFFFF) % HASHSIZE;
}
}
private class BitFile
{
private OutputStream stream_ = null;
private byte[] buffer_;
private int streamIndex_, bitsLeft_;
BitFile(OutputStream stream)
{
stream_ = stream;
buffer_ = new byte[256];
streamIndex_ = 0;
bitsLeft_ = 8;
}
void flush()
throws IOException
{
int nBytes = streamIndex_ + ((bitsLeft_ == 8) ? 0 : 1);
if (nBytes > 0) {
stream_.write (nBytes);
stream_.write (buffer_, 0, nBytes);
buffer_[0] = 0;
streamIndex_ = 0;
bitsLeft_ = 8;
}
}
void writeBits (int bits, int nBits)
throws IOException
{
int nBitsWritten = 0;
int nBytes = 255;
do {
if ((streamIndex_ == 254 && bitsLeft_ == 0) || streamIndex_ > 254) {
stream_.write (nBytes);
stream_.write (buffer_, 0, nBytes);
buffer_[0] = 0;
streamIndex_ = 0;
bitsLeft_ = 8;
}
if (nBits <= bitsLeft_) {
buffer_[streamIndex_] |= (bits & ((1 << nBits) - 1)) << (8 - bitsLeft_);
nBitsWritten += nBits;
bitsLeft_ -= nBits;
nBits = 0;
}
else {
buffer_[streamIndex_] |= (bits & ((1 << bitsLeft_) - 1)) <<
(8 - bitsLeft_);
nBitsWritten += bitsLeft_;
bits >>= bitsLeft_;
nBits -= bitsLeft_;
buffer_[++streamIndex_] = 0;
bitsLeft_ = 8;
}
} while (nBits != 0);
}
}
}
</source>
Converting GIF to PostScript
<source lang="java"> import java.io.FileInputStream; import java.io.FileOutputStream; import javax.print.Doc; import javax.print.DocFlavor; import javax.print.DocPrintJob; import javax.print.SimpleDoc; import javax.print.StreamPrintService; import javax.print.StreamPrintServiceFactory; import javax.print.attribute.HashPrintRequestAttributeSet; import javax.print.attribute.PrintRequestAttributeSet; public class StreamOneFour {
public static void main(String args[]) throws Exception {
String infile = "StreamOneFour.java";
DocFlavor flavor = DocFlavor.INPUT_STREAM.GIF;
String mimeType = DocFlavor.INPUT_STREAM.POSTSCRIPT.getMimeType();
StreamPrintServiceFactory[] factories = StreamPrintServiceFactory
.lookupStreamPrintServiceFactories(flavor, mimeType);
String filename = "out.ps";
FileOutputStream fos = new FileOutputStream(filename);
StreamPrintService sps = factories[0].getPrintService(fos);
FileInputStream fis = new FileInputStream(infile);
DocPrintJob dpj = sps.createPrintJob();
PrintRequestAttributeSet pras = new HashPrintRequestAttributeSet();
Doc doc = new SimpleDoc(fis, flavor, null);
dpj.print(doc, pras);
fos.close();
}
}
</source>
Decodes a GIF file into one or more frames
<source lang="java">
import java.net.*; import java.io.*; import java.util.*; import java.awt.*; import java.awt.image.*; /**
* Class GifDecoder - Decodes a GIF file into one or more frames.*
* Example:
* GifDecoder d = new GifDecoder();
* d.read("sample.gif");
* int n = d.getFrameCount();
* for (int i = 0; i < n; i++) {
* BufferedImage frame = d.getFrame(i); // frame i
* int t = d.getDelay(i); // display duration of frame in milliseconds
* // do something with frame
* }
*
* No copyright asserted on the source code of this class. May be used for * any purpose, however, refer to the Unisys LZW patent for any additional * restrictions. Please forward any corrections to kweiner@fmsware.ru. * * @author Kevin Weiner, FM Software; LZW decoder adapted from John Cristy"s ImageMagick. * @version 1.03 November 2003 * */
public class GifDecoder {
/**
* File read status: No errors.
*/
public static final int STATUS_OK = 0;
/**
* File read status: Error decoding file (may be partially decoded)
*/
public static final int STATUS_FORMAT_ERROR = 1;
/**
* File read status: Unable to open source.
*/
public static final int STATUS_OPEN_ERROR = 2;
protected BufferedInputStream in;
protected int status;
protected int width; // full image width
protected int height; // full image height
protected boolean gctFlag; // global color table used
protected int gctSize; // size of global color table
protected int loopCount = 1; // iterations; 0 = repeat forever
protected int[] gct; // global color table
protected int[] lct; // local color table
protected int[] act; // active color table
protected int bgIndex; // background color index
protected int bgColor; // background color
protected int lastBgColor; // previous bg color
protected int pixelAspect; // pixel aspect ratio
protected boolean lctFlag; // local color table flag
protected boolean interlace; // interlace flag
protected int lctSize; // local color table size
protected int ix, iy, iw, ih; // current image rectangle
protected Rectangle lastRect; // last image rect
protected BufferedImage image; // current frame
protected BufferedImage lastImage; // previous frame
protected byte[] block = new byte[256]; // current data block
protected int blockSize = 0; // block size
// last graphic control extension info
protected int dispose = 0;
// 0=no action; 1=leave in place; 2=restore to bg; 3=restore to prev
protected int lastDispose = 0;
protected boolean transparency = false; // use transparent color
protected int delay = 0; // delay in milliseconds
protected int transIndex; // transparent color index
protected static final int MaxStackSize = 4096;
// max decoder pixel stack size
// LZW decoder working arrays
protected short[] prefix;
protected byte[] suffix;
protected byte[] pixelStack;
protected byte[] pixels;
protected ArrayList frames; // frames read from current file
protected int frameCount;
static class GifFrame {
public GifFrame(BufferedImage im, int del) {
image = im;
delay = del;
}
public BufferedImage image;
public int delay;
}
/**
* Gets display duration for specified frame.
*
* @param n int index of frame
* @return delay in milliseconds
*/
public int getDelay(int n) {
//
delay = -1;
if ((n >= 0) && (n < frameCount)) {
delay = ((GifFrame) frames.get(n)).delay;
}
return delay;
}
/**
* Gets the number of frames read from file.
* @return frame count
*/
public int getFrameCount() {
return frameCount;
}
/**
* Gets the first (or only) image read.
*
* @return BufferedImage containing first frame, or null if none.
*/
public BufferedImage getImage() {
return getFrame(0);
}
/**
* Gets the "Netscape" iteration count, if any.
* A count of 0 means repeat indefinitiely.
*
* @return iteration count if one was specified, else 1.
*/
public int getLoopCount() {
return loopCount;
}
/**
* Creates new frame image from current data (and previous
* frames as specified by their disposition codes).
*/
protected void setPixels() {
// expose destination image"s pixels as int array
int[] dest =
((DataBufferInt) image.getRaster().getDataBuffer()).getData();
// fill in starting image contents based on last image"s dispose code
if (lastDispose > 0) {
if (lastDispose == 3) {
// use image before last
int n = frameCount - 2;
if (n > 0) {
lastImage = getFrame(n - 1);
} else {
lastImage = null;
}
}
if (lastImage != null) {
int[] prev =
((DataBufferInt) lastImage.getRaster().getDataBuffer()).getData();
System.arraycopy(prev, 0, dest, 0, width * height);
// copy pixels
if (lastDispose == 2) {
// fill last image rect area with background color
Graphics2D g = image.createGraphics();
Color c = null;
if (transparency) {
c = new Color(0, 0, 0, 0); // assume background is transparent
} else {
c = new Color(lastBgColor); // use given background color
}
g.setColor(c);
g.setComposite(AlphaComposite.Src); // replace area
g.fill(lastRect);
g.dispose();
}
}
}
// copy each source line to the appropriate place in the destination
int pass = 1;
int inc = 8;
int iline = 0;
for (int i = 0; i < ih; i++) {
int line = i;
if (interlace) {
if (iline >= ih) {
pass++;
switch (pass) {
case 2 :
iline = 4;
break;
case 3 :
iline = 2;
inc = 4;
break;
case 4 :
iline = 1;
inc = 2;
}
}
line = iline;
iline += inc;
}
line += iy;
if (line < height) {
int k = line * width;
int dx = k + ix; // start of line in dest
int dlim = dx + iw; // end of dest line
if ((k + width) < dlim) {
dlim = k + width; // past dest edge
}
int sx = i * iw; // start of line in source
while (dx < dlim) {
// map color and insert in destination
int index = ((int) pixels[sx++]) & 0xff;
int c = act[index];
if (c != 0) {
dest[dx] = c;
}
dx++;
}
}
}
}
/**
* Gets the image contents of frame n.
*
* @return BufferedImage representation of frame, or null if n is invalid.
*/
public BufferedImage getFrame(int n) {
BufferedImage im = null;
if ((n >= 0) && (n < frameCount)) {
im = ((GifFrame) frames.get(n)).image;
}
return im;
}
/**
* Gets image size.
*
* @return GIF image dimensions
*/
public Dimension getFrameSize() {
return new Dimension(width, height);
}
/**
* Reads GIF image from stream
*
* @param BufferedInputStream containing GIF file.
* @return read status code (0 = no errors)
*/
public int read(BufferedInputStream is) {
init();
if (is != null) {
in = is;
readHeader();
if (!err()) {
readContents();
if (frameCount < 0) {
status = STATUS_FORMAT_ERROR;
}
}
} else {
status = STATUS_OPEN_ERROR;
}
try {
is.close();
} catch (IOException e) {
}
return status;
}
/**
* Reads GIF image from stream
*
* @param InputStream containing GIF file.
* @return read status code (0 = no errors)
*/
public int read(InputStream is) {
init();
if (is != null) {
if (!(is instanceof BufferedInputStream))
is = new BufferedInputStream(is);
in = (BufferedInputStream) is;
readHeader();
if (!err()) {
readContents();
if (frameCount < 0) {
status = STATUS_FORMAT_ERROR;
}
}
} else {
status = STATUS_OPEN_ERROR;
}
try {
is.close();
} catch (IOException e) {
}
return status;
}
/**
* Reads GIF file from specified file/URL source
* (URL assumed if name contains ":/" or "file:")
*
* @param name String containing source
* @return read status code (0 = no errors)
*/
public int read(String name) {
status = STATUS_OK;
try {
name = name.trim().toLowerCase();
if ((name.indexOf("file:") >= 0) ||
(name.indexOf(":/") > 0)) {
URL url = new URL(name);
in = new BufferedInputStream(url.openStream());
} else {
in = new BufferedInputStream(new FileInputStream(name));
}
status = read(in);
} catch (IOException e) {
status = STATUS_OPEN_ERROR;
}
return status;
}
/**
* Decodes LZW image data into pixel array.
* Adapted from John Cristy"s ImageMagick.
*/
protected void decodeImageData() {
int NullCode = -1;
int npix = iw * ih;
int available,
clear,
code_mask,
code_size,
end_of_information,
in_code,
old_code,
bits,
code,
count,
i,
datum,
data_size,
first,
top,
bi,
pi;
if ((pixels == null) || (pixels.length < npix)) {
pixels = new byte[npix]; // allocate new pixel array
}
if (prefix == null) prefix = new short[MaxStackSize];
if (suffix == null) suffix = new byte[MaxStackSize];
if (pixelStack == null) pixelStack = new byte[MaxStackSize + 1];
// Initialize GIF data stream decoder.
data_size = read();
clear = 1 << data_size;
end_of_information = clear + 1;
available = clear + 2;
old_code = NullCode;
code_size = data_size + 1;
code_mask = (1 << code_size) - 1;
for (code = 0; code < clear; code++) {
prefix[code] = 0;
suffix[code] = (byte) code;
}
// Decode GIF pixel stream.
datum = bits = count = first = top = pi = bi = 0;
for (i = 0; i < npix;) {
if (top == 0) {
if (bits < code_size) {
// Load bytes until there are enough bits for a code.
if (count == 0) {
// Read a new data block.
count = readBlock();
if (count <= 0)
break;
bi = 0;
}
datum += (((int) block[bi]) & 0xff) << bits;
bits += 8;
bi++;
count--;
continue;
}
// Get the next code.
code = datum & code_mask;
datum >>= code_size;
bits -= code_size;
// Interpret the code
if ((code > available) || (code == end_of_information))
break;
if (code == clear) {
// Reset decoder.
code_size = data_size + 1;
code_mask = (1 << code_size) - 1;
available = clear + 2;
old_code = NullCode;
continue;
}
if (old_code == NullCode) {
pixelStack[top++] = suffix[code];
old_code = code;
first = code;
continue;
}
in_code = code;
if (code == available) {
pixelStack[top++] = (byte) first;
code = old_code;
}
while (code > clear) {
pixelStack[top++] = suffix[code];
code = prefix[code];
}
first = ((int) suffix[code]) & 0xff;
// Add a new string to the string table,
if (available >= MaxStackSize)
break;
pixelStack[top++] = (byte) first;
prefix[available] = (short) old_code;
suffix[available] = (byte) first;
available++;
if (((available & code_mask) == 0)
&& (available < MaxStackSize)) {
code_size++;
code_mask += available;
}
old_code = in_code;
}
// Pop a pixel off the pixel stack.
top--;
pixels[pi++] = pixelStack[top];
i++;
}
for (i = pi; i < npix; i++) {
pixels[i] = 0; // clear missing pixels
}
}
/**
* Returns true if an error was encountered during reading/decoding
*/
protected boolean err() {
return status != STATUS_OK;
}
/**
* Initializes or re-initializes reader
*/
protected void init() {
status = STATUS_OK;
frameCount = 0;
frames = new ArrayList();
gct = null;
lct = null;
}
/**
* Reads a single byte from the input stream.
*/
protected int read() {
int curByte = 0;
try {
curByte = in.read();
} catch (IOException e) {
status = STATUS_FORMAT_ERROR;
}
return curByte;
}
/**
* Reads next variable length block from input.
*
* @return number of bytes stored in "buffer"
*/
protected int readBlock() {
blockSize = read();
int n = 0;
if (blockSize > 0) {
try {
int count = 0;
while (n < blockSize) {
count = in.read(block, n, blockSize - n);
if (count == -1)
break;
n += count;
}
} catch (IOException e) {
}
if (n < blockSize) {
status = STATUS_FORMAT_ERROR;
}
}
return n;
}
/**
* Reads color table as 256 RGB integer values
*
* @param ncolors int number of colors to read
* @return int array containing 256 colors (packed ARGB with full alpha)
*/
protected int[] readColorTable(int ncolors) {
int nbytes = 3 * ncolors;
int[] tab = null;
byte[] c = new byte[nbytes];
int n = 0;
try {
n = in.read(c);
} catch (IOException e) {
}
if (n < nbytes) {
status = STATUS_FORMAT_ERROR;
} else {
tab = new int[256]; // max size to avoid bounds checks
int i = 0;
int j = 0;
while (i < ncolors) {
int r = ((int) c[j++]) & 0xff;
int g = ((int) c[j++]) & 0xff;
int b = ((int) c[j++]) & 0xff;
tab[i++] = 0xff000000 | (r << 16) | (g << 8) | b;
}
}
return tab;
}
/**
* Main file parser. Reads GIF content blocks.
*/
protected void readContents() {
// read GIF file content blocks
boolean done = false;
while (!(done || err())) {
int code = read();
switch (code) {
case 0x2C : // image separator
readImage();
break;
case 0x21 : // extension
code = read();
switch (code) {
case 0xf9 : // graphics control extension
readGraphicControlExt();
break;
case 0xff : // application extension
readBlock();
String app = "";
for (int i = 0; i < 11; i++) {
app += (char) block[i];
}
if (app.equals("NETSCAPE2.0")) {
readNetscapeExt();
}
else
skip(); // don"t care
break;
default : // uninteresting extension
skip();
}
break;
case 0x3b : // terminator
done = true;
break;
case 0x00 : // bad byte, but keep going and see what happens
break;
default :
status = STATUS_FORMAT_ERROR;
}
}
}
/**
* Reads Graphics Control Extension values
*/
protected void readGraphicControlExt() {
read(); // block size
int packed = read(); // packed fields
dispose = (packed & 0x1c) >> 2; // disposal method
if (dispose == 0) {
dispose = 1; // elect to keep old image if discretionary
}
transparency = (packed & 1) != 0;
delay = readShort() * 10; // delay in milliseconds
transIndex = read(); // transparent color index
read(); // block terminator
}
/**
* Reads GIF file header information.
*/
protected void readHeader() {
String id = "";
for (int i = 0; i < 6; i++) {
id += (char) read();
}
if (!id.startsWith("GIF")) {
status = STATUS_FORMAT_ERROR;
return;
}
readLSD();
if (gctFlag && !err()) {
gct = readColorTable(gctSize);
bgColor = gct[bgIndex];
}
}
/**
* Reads next frame image
*/
protected void readImage() {
ix = readShort(); // (sub)image position & size
iy = readShort();
iw = readShort();
ih = readShort();
int packed = read();
lctFlag = (packed & 0x80) != 0; // 1 - local color table flag
interlace = (packed & 0x40) != 0; // 2 - interlace flag
// 3 - sort flag
// 4-5 - reserved
lctSize = 2 << (packed & 7); // 6-8 - local color table size
if (lctFlag) {
lct = readColorTable(lctSize); // read table
act = lct; // make local table active
} else {
act = gct; // make global table active
if (bgIndex == transIndex)
bgColor = 0;
}
int save = 0;
if (transparency) {
save = act[transIndex];
act[transIndex] = 0; // set transparent color if specified
}
if (act == null) {
status = STATUS_FORMAT_ERROR; // no color table defined
}
if (err()) return;
decodeImageData(); // decode pixel data
skip();
if (err()) return;
frameCount++;
// create new image to receive frame data
image =
new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB_PRE);
setPixels(); // transfer pixel data to image
frames.add(new GifFrame(image, delay)); // add image to frame list
if (transparency) {
act[transIndex] = save;
}
resetFrame();
}
/**
* Reads Logical Screen Descriptor
*/
protected void readLSD() {
// logical screen size
width = readShort();
height = readShort();
// packed fields
int packed = read();
gctFlag = (packed & 0x80) != 0; // 1 : global color table flag
// 2-4 : color resolution
// 5 : gct sort flag
gctSize = 2 << (packed & 7); // 6-8 : gct size
bgIndex = read(); // background color index
pixelAspect = read(); // pixel aspect ratio
}
/**
* Reads Netscape extenstion to obtain iteration count
*/
protected void readNetscapeExt() {
do {
readBlock();
if (block[0] == 1) {
// loop count sub-block
int b1 = ((int) block[1]) & 0xff;
int b2 = ((int) block[2]) & 0xff;
loopCount = (b2 << 8) | b1;
}
} while ((blockSize > 0) && !err());
}
/**
* Reads next 16-bit value, LSB first
*/
protected int readShort() {
// read 16-bit value, LSB first
return read() | (read() << 8);
}
/**
* Resets frame state for reading next image.
*/
protected void resetFrame() {
lastDispose = dispose;
lastRect = new Rectangle(ix, iy, iw, ih);
lastImage = image;
lastBgColor = bgColor;
dispose = 0;
transparency = false;
delay = 0;
lct = null;
}
/**
* Skips variable length blocks up to and including
* next zero length block.
*/
protected void skip() {
do {
readBlock();
} while ((blockSize > 0) && !err());
}
}
</source>
Get Gif Properties
<source lang="java"> /*
* Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */
// Revised from apache cocoon import java.io.File; import java.io.FileNotFoundException; import java.io.IOException; import java.io.BufferedInputStream; import java.io.FileInputStream; /**
* @version $Id: ImageUtils.java 587751 2007-10-24 02:41:36Z vgritsenko $ */
final public class ImageUtils {
final public static ImageProperties getJpegProperties(File file) throws FileNotFoundException, IOException{
BufferedInputStream in = null;
try {
in = new BufferedInputStream(new FileInputStream(file));
// check for "magic" header
byte[] buf = new byte[2];
int count = in.read(buf, 0, 2);
if (count < 2) {
throw new RuntimeException("Not a valid Jpeg file!");
}
if ((buf[0]) != (byte) 0xFF || (buf[1]) != (byte) 0xD8) {
throw new RuntimeException("Not a valid Jpeg file!");
}
int width = 0;
int height = 0;
char[] comment = null;
boolean hasDims = false;
boolean hasComment = false;
int ch = 0;
while (ch != 0xDA && !(hasDims && hasComment)) {
/* Find next marker (JPEG markers begin with 0xFF) */
while (ch != 0xFF) {
ch = in.read();
}
/* JPEG markers can be padded with unlimited 0xFF"s */
while (ch == 0xFF) {
ch = in.read();
}
/* Now, ch contains the value of the marker. */
int length = 256 * in.read();
length += in.read();
if (length < 2) {
throw new RuntimeException("Not a valid Jpeg file!");
}
/* Now, length contains the length of the marker. */
if (ch >= 0xC0 && ch <= 0xC3) {
in.read();
height = 256 * in.read();
height += in.read();
width = 256 * in.read();
width += in.read();
for (int foo = 0; foo < length - 2 - 5; foo++) {
in.read();
}
hasDims = true;
}
else if (ch == 0xFE) {
// that"s the comment marker
comment = new char[length-2];
for (int foo = 0; foo < length - 2; foo++)
comment[foo] = (char) in.read();
hasComment = true;
}
else {
// just skip marker
for (int foo = 0; foo < length - 2; foo++) {
in.read();
}
}
}
return (new ImageProperties(width, height, comment, "jpeg"));
}
finally {
if (in != null) {
try {
in.close();
}
catch (IOException e) {
}
}
}
}
final public static ImageProperties getGifProperties(File file) throws FileNotFoundException, IOException{
BufferedInputStream in = null;
try {
in = new BufferedInputStream(new FileInputStream(file));
byte[] buf = new byte[10];
int count = in.read(buf, 0, 10);
if (count < 10) {
throw new RuntimeException("Not a valid Gif file!");
}
if ((buf[0]) != (byte) "G" || (buf[1]) != (byte) "I" || (buf[2]) != (byte) "F") {
throw new RuntimeException("Not a valid Gif file!");
}
int w1 = (buf[6] & 0xff) | (buf[6] & 0x80);
int w2 = (buf[7] & 0xff) | (buf[7] & 0x80);
int h1 = (buf[8] & 0xff) | (buf[8] & 0x80);
int h2 = (buf[9] & 0xff) | (buf[9] & 0x80);
int width = w1 + (w2 << 8);
int height = h1 + (h2 << 8);
return (new ImageProperties(width, height, null,"gif"));
}
finally {
if (in != null) {
try {
in.close();
}
catch (IOException e) {
}
}
}
}
} /*
* Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */
/**
* @version $Id: ImageProperties.java 587751 2007-10-24 02:41:36Z vgritsenko $ */
final class ImageProperties {
final public int width;
final public int height;
final public char[] comment;
final public String type;
public ImageProperties(int width, int height, char[] comment, String type) {
this.width = width;
this.height = height;
this.rument = comment;
this.type = type;
}
public String toString() {
StringBuffer sb = new StringBuffer();
sb.append(type).append(" ").append(width).append("x").append(height);
if (comment != null) {
sb.append(" (").append(comment).append(")");
}
return (sb.toString());
}
}
</source>
Gif Encoder
<source lang="java"> /*
* * Part of the InfoGlue Content Management Platform (www.infoglue.org) * * * * Copyright (C) * * This program is free software; you can redistribute it and/or modify it under * the terms of the GNU General Public License version 2, as published by the * Free Software Foundation. See the file LICENSE.html for more information. * * This program is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY, including the implied warranty of MERCHANTABILITY or FITNESS * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. * * You should have received a copy of the GNU General Public License along with * this program; if not, write to the Free Software Foundation, Inc. / 59 Temple * Place, Suite 330 / Boston, MA 02111-1307 / USA. * * */
import java.awt.Color; import java.awt.image.BufferedImage; import java.io.*; import java.util.*; public class GifEncoder {
String b;
int g;
int a;
int h;
int f;
int c[];
int i[];
int e[];
TreeSet d;
private void a(int ai[], int j, DataOutputStream dataoutputstream) throws Exception
{
try
{
boolean flag2 = false;
int l;
int j3 = (1 << (l = j + 1)) - 1;
int i2 = (1 << j) + 2;
byte abyte0[] = new byte[255];
int ai1[] = new int[4096];
int ai2[] = new int[4096];
int ai3[] = new int[4096];
int ai4[] = new int[i2];
int k;
for(k = 0; k < i2; k++)
{
ai4[k] = 0xffffffff | k;
ai3[k] = -1;
}
for(; k < 4096; k++)
{
ai3[k] = -1;
}
System.arraycopy(ai3, 0, ai1, 0, 4096);
System.arraycopy(ai3, 0, ai2, 0, 4096);
System.arraycopy(ai4, 0, ai1, 0, i2);
int j1 = ai[0];
k = 1;
boolean flag1 = false;
int j2 = 0;
int k2 = (1 << l) - 1;
boolean flag = true;
int i3 = 0;
int i1 = 0;
j2 |= 1 << j + i3;
for(i3 += l; i3 >= 8;)
{
try
{
abyte0[i1++] = (byte)j2;
}
catch(ArrayIndexOutOfBoundsException arrayindexoutofboundsexception)
{
dataoutputstream.writeByte(255);
dataoutputstream.write(abyte0);
abyte0[i1 = 0] = (byte)j2;
i1++;
}
i3 -= 8;
j2 >>= 8;
}
try
{
do
{
int k1;
int l1 = j1 << 16 | (k1 = ai[k++]);
int k3;
for(k3 = j1; ai1[k3] != l1 && ai2[k3] >= 0; k3 = ai2[k3]) { }
if(ai1[k3] != l1)
{
j2 |= j1 << i3;
for(i3 += l; i3 >= 8;)
{
try
{
abyte0[i1++] = (byte)j2;
}
catch(ArrayIndexOutOfBoundsException arrayindexoutofboundsexception1)
{
dataoutputstream.writeByte(255);
dataoutputstream.write(abyte0);
abyte0[i1 = 0] = (byte)j2;
i1++;
}
i3 -= 8;
j2 >>= 8;
}
if(i2 > j3)
{
l++;
j3 = (j3 << 1) + 1;
}
try
{
ai2[k3] = i2;
ai1[i2++] = j1 << 16 | k1;
j1 = k1;
}
catch(ArrayIndexOutOfBoundsException arrayindexoutofboundsexception2)
{
j1 = k1;
l--;
j2 |= 1 << j + i3;
for(i3 += l; i3 >= 8;)
{
try
{
abyte0[i1++] = (byte)j2;
}
catch(ArrayIndexOutOfBoundsException arrayindexoutofboundsexception5)
{
dataoutputstream.writeByte(255);
dataoutputstream.write(abyte0);
abyte0[i1 = 0] = (byte)j2;
i1++;
}
i3 -= 8;
j2 >>= 8;
}
j3 = (1 << (l = j + 1)) - 1;
i2 = (1 << j) + 2;
int l2 = (1 << l) - 1;
System.arraycopy(ai3, 0, ai1, 0, 4096);
System.arraycopy(ai3, 0, ai2, 0, 4096);
System.arraycopy(ai4, 0, ai1, 0, i2);
}
}
else
{
j1 = k3;
}
}
while(true);
}
catch(Exception exception)
{
j2 |= j1 << i3;
}
for(i3 += l; i3 >= 8;)
{
try
{
abyte0[i1++] = (byte)j2;
}
catch(ArrayIndexOutOfBoundsException arrayindexoutofboundsexception3)
{
dataoutputstream.writeByte(255);
dataoutputstream.write(abyte0);
abyte0[i1 = 0] = (byte)j2;
i1++;
}
i3 -= 8;
j2 >>= 8;
}
j2 |= (1 << j) + 1 << i3;
for(i3 += l; i3 > 0;)
{
try
{
abyte0[i1++] = (byte)j2;
}
catch(ArrayIndexOutOfBoundsException arrayindexoutofboundsexception4)
{
dataoutputstream.writeByte(255);
dataoutputstream.write(abyte0);
abyte0[i1 = 0] = (byte)j2;
i1++;
}
i3 -= 8;
j2 >>= 8;
}
dataoutputstream.writeByte(i1);
dataoutputstream.write(abyte0, 0, i1);
dataoutputstream.writeByte(0);
return;
}
catch(Exception e) { }
}
public void addTransparentColor(Color color)
{
try
{
if(f < 256)
{
c[f++] = color.getRGB();
}
return;
}
catch(Exception e) { }
}
public void setTransparentColors(Vector vector)
{
try
{
Iterator iterator = vector.iterator();
while(iterator.hasNext())
{
Color color = (Color)iterator.next();
addTransparentColor(color);
}
return;
}
catch(Exception e) { }
}
public void encode(BufferedImage bufferedimage, DataOutputStream dataoutputstream, Hashtable hashtable) throws Exception
{
try
{
a = bufferedimage.getWidth();
g = bufferedimage.getHeight();
e = bufferedimage.getRGB(0, 0, a, g, null, 0, a);
int i4 = 0;
b = hashtable.get("encoding").toString();
if(b.equals("websafe"))
{
int ai[] = new int[256];
i = new int[256];
h = 8;
int k1 = 0;
int j;
int j1 = j = 0;
for(; j <= 255; j += 51)
{
for(int l = 0; l <= 255; l += 51)
{
for(int i1 = 0; i1 <= 255;)
{
i[j1] = (j << 16) + (l << 8) + i1;
ai[k1++] = j1;
i1 += 51;
j1++;
}
}
}
if(f > 0)
{
int j4 = c[0];
int l1 = ((c[0] >> 16 & 0xff) + 25) / 51;
int k2 = ((c[0] >> 8 & 0xff) + 25) / 51;
int j3 = ((c[0] & 0xff) + 25) / 51;
i4 = l1 * 36 + k2 * 6 + j3;
for(j = 1; j < f; j++)
{
int i2 = ((c[j] >> 16 & 0xff) + 25) / 51;
int l2 = ((c[j] >> 8 & 0xff) + 25) / 51;
int k3 = ((c[j] & 0xff) + 25) / 51;
ai[i2 * 36 + l2 * 6 + k3] = i4;
}
}
j = 0;
try
{
do
{
int i5 = e[j];
int j2 = ((i5 >> 16 & 0xff) + 25) / 51;
int i3 = ((i5 >> 8 & 0xff) + 25) / 51;
int l3 = ((i5 & 0xff) + 25) / 51;
e[j++] = ai[j2 * 36 + i3 * 6 + l3];
}
while(true);
}
catch(Exception exception1) { }
}
/*else
if(b.equals("optimized"))
{
try
{
int k4 = Integer.parseInt(hashtable.get("colors").toString());
for(h = 1; k4 - 1 >> h > 0; h++) { }
i = new int[1 << h];
CSelectiveQuant cselectivequant = new CSelectiveQuant();
for(int j5 = 0; j5 < e.length; j5++)
{
cselectivequant.addPixel(e[j5]);
}
boolean flag = f > 0;
int k5 = flag ? 1 : 0;
int ai1[] = cselectivequant.createPalette(k4 - k5);
for(int l5 = 0; l5 < i.length; l5++)
{
try
{
i[l5] = ai1[l5 - k5];
}
catch(ArrayIndexOutOfBoundsException arrayindexoutofboundsexception)
{
i[l5] = 0;
}
}
if(flag)
{
i4 = 0;
for(int i6 = 0; i6 < f; i6++)
{
cselectivequant.setIndex(c[i6], -1);
}
}
for(int j6 = 0; j6 < e.length; j6++)
{
e[j6] = cselectivequant.getIndex(e[j6]) + k5;
}
}
catch(NumberFormatException numberformatexception)
{
CmsLogger.logInfo("Parameter: "colors" is malformated...");
return;
}
}
*/
dataoutputstream.write("GIF89a".getBytes());
dataoutputstream.writeByte(a);
dataoutputstream.writeByte(a >> 8);
dataoutputstream.writeByte(g);
dataoutputstream.writeByte(g >> 8);
dataoutputstream.writeByte(0xf0 | h - 1);
dataoutputstream.writeByte(0);
dataoutputstream.writeByte(0);
int k = 0;
try
{
do
{
int l4 = i[k++];
dataoutputstream.writeByte(l4 >> 16 & 0xff);
dataoutputstream.writeByte(l4 >> 8 & 0xff);
dataoutputstream.writeByte(l4 & 0xff);
}
while(true);
}
catch(Exception exception) { }
if(f > 0)
{
dataoutputstream.writeByte(33);
dataoutputstream.writeByte(249);
dataoutputstream.writeByte(4);
dataoutputstream.writeByte(1);
dataoutputstream.writeByte(0);
dataoutputstream.writeByte(0);
dataoutputstream.writeByte(i4);
dataoutputstream.writeByte(0);
}
dataoutputstream.writeByte(44);
dataoutputstream.writeByte(0);
dataoutputstream.writeByte(0);
dataoutputstream.writeByte(0);
dataoutputstream.writeByte(0);
dataoutputstream.writeByte(a);
dataoutputstream.writeByte(a >> 8);
dataoutputstream.writeByte(g);
dataoutputstream.writeByte(g >> 8);
dataoutputstream.writeByte(0);
dataoutputstream.writeByte(h);
a(e, h, dataoutputstream);
dataoutputstream.writeByte(59);
dataoutputstream.flush();
return;
}
catch(Exception e) { }
}
public GifEncoder()
{
f = 0;
c = new int[256];
}
}
</source>
Gif Encoder implements ImageConsumer
<source lang="java"> //** Copyright Statement *************************************************** //The Salmon Open Framework for Internet Applications (SOFIA) // Copyright (C) 1999 - 2002, Salmon LLC // // This program is free software; you can redistribute it and/or // modify it under the terms of the GNU General Public License version 2 // as published by the Free Software Foundation; // // This program is distributed in the hope that it will be useful, // but WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the // GNU General Public License for more details. // // You should have received a copy of the GNU General Public License // along with this program; if not, write to the Free Software // Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. // // For more information please visit http://www.salmonllc.ru //** End Copyright Statement ***************************************************
// ImageEncoder - abstract class for writing out an image // // Copyright (C) 1996 by Jef Poskanzer <jef@acme.ru>. All rights reserved. // // Redistribution and use in source and binary forms, with or without // modification, are permitted provided that the following conditions // are met: // 1. Redistributions of source code must retain the above copyright // notice, this list of conditions and the following disclaimer. // 2. Redistributions in binary form must reproduce the above copyright // notice, this list of conditions and the following disclaimer in the // documentation and/or other materials provided with the distribution. // // THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS"" AND // ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE // IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE // ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE // FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL // DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS // OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) // HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT // LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY // OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF // SUCH DAMAGE. // // Visit the ACME Labs Java page for up-to-date versions of this and other // fine Java utilities: http://www.acme.ru/java/ import java.util.*; import java.io.*; import java.awt.Image; import java.awt.image.*; import java.awt.*; /**
* Class for writing out an image as a gif. */
public class GifEncoder implements ImageConsumer {
protected OutputStream out;
private ImageProducer producer;
private int width = -1;
private int height = -1;
private int hintflags = 0;
private boolean started = false;
private boolean encoding;
private IOException iox;
private static final ColorModel rgbModel = ColorModel.getRGBdefault();
private Hashtable props = null;
private boolean accumulate = false;
private int[] accumulator;
private boolean interlace = false;
int[][] rgbPixels;
IntHashtable colorHash;
// Adapted from ppmtogif, which is based on GIFENCOD by David
// Rowley <mgardi@watdscu.waterloo.edu>. Lempel-Zim compression
// based on "compress".
int Width, Height;
boolean Interlace;
int curx, cury;
int CountDown;
int Pass = 0;
static final int EOF = -1;
// 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};
// GIF Specific routines
// Number of characters so far in this "packet"
int a_count;
// Define the storage for the packet accumulator
byte[] accum = new byte[256];
class gifHashitem {
public int rgb;
public int count;
public int index;
public boolean isTransparent;
public gifHashitem(int rgb, int count, int index, boolean isTransparent) {
this.rgb = rgb;
this.count = count;
this.index = index;
this.isTransparent = isTransparent;
}
}
class IntHashtableEntry {
int hash;
int key;
Object value;
IntHashtableEntry next;
protected Object clone() {
IntHashtableEntry entry = new IntHashtableEntry();
entry.hash = hash;
entry.key = key;
entry.value = value;
entry.next = (next != null) ? (IntHashtableEntry) next.clone() : null;
return entry;
}
}
class IntHashtable extends Dictionary implements Cloneable {
private IntHashtableEntry table[];
private int count;
private int threshold;
private float loadFactor;
public IntHashtable() {
this(101, 0.75f);
}
public IntHashtable(int initialCapacity) {
this(initialCapacity, 0.75f);
}
public IntHashtable(int initialCapacity, float loadFactor) {
if (initialCapacity <= 0 || loadFactor <= 0.0)
throw new IllegalArgumentException();
this.loadFactor = loadFactor;
table = new IntHashtableEntry[initialCapacity];
threshold = (int) (initialCapacity * loadFactor);
}
public synchronized void clear() {
IntHashtableEntry tab[] = table;
for (int index = tab.length; --index >= 0;)
tab[index] = null;
count = 0;
}
public synchronized Object clone() {
try {
IntHashtable t = (IntHashtable) super.clone();
t.table = new IntHashtableEntry[table.length];
for (int i = table.length; i-- > 0;)
t.table[i] = (table[i] != null) ? (IntHashtableEntry) table[i].clone() : null;
return t;
} catch (CloneNotSupportedException e) {
throw new InternalError();
}
}
public synchronized boolean contains(Object value) {
if (value == null)
throw new NullPointerException();
IntHashtableEntry tab[] = table;
for (int i = tab.length; i-- > 0;) {
for (IntHashtableEntry e = tab[i]; e != null; e = e.next) {
if (e.value.equals(value))
return true;
}
}
return false;
}
public synchronized boolean containsKey(int key) {
IntHashtableEntry tab[] = table;
int hash = key;
int index = (hash & 0x7FFFFFFF) % tab.length;
for (IntHashtableEntry e = tab[index]; e != null; e = e.next) {
if (e.hash == hash && e.key == key)
return true;
}
return false;
}
public synchronized Enumeration elements() {
return new IntHashtableEnumerator(table, false);
}
public synchronized Object get(int key) {
IntHashtableEntry tab[] = table;
int hash = key;
int index = (hash & 0x7FFFFFFF) % tab.length;
for (IntHashtableEntry e = tab[index]; e != null; e = e.next) {
if (e.hash == hash && e.key == key)
return e.value;
}
return null;
}
public Object get(Object okey) {
if (!(okey instanceof Integer))
throw new InternalError("key is not an Integer");
Integer ikey = (Integer) okey;
int key = ikey.intValue();
return get(key);
}
public boolean isEmpty() {
return count == 0;
}
public synchronized Enumeration keys() {
return new IntHashtableEnumerator(table, true);
}
public synchronized Object put(int key, Object value) {
if (value == null)
throw new NullPointerException();
IntHashtableEntry tab[] = table;
int hash = key;
int index = (hash & 0x7FFFFFFF) % tab.length;
for (IntHashtableEntry e = tab[index]; e != null; e = e.next) {
if (e.hash == hash && e.key == key) {
Object old = e.value;
e.value = value;
return old;
}
}
if (count >= threshold) {
rehash();
return put(key, value);
}
IntHashtableEntry e = new IntHashtableEntry();
e.hash = hash;
e.key = key;
e.value = value;
e.next = tab[index];
tab[index] = e;
++count;
return null;
}
public Object put(Object okey, Object value) {
if (!(okey instanceof Integer))
throw new InternalError("key is not an Integer");
Integer ikey = (Integer) okey;
int key = ikey.intValue();
return put(key, value);
}
protected void rehash() {
int oldCapacity = table.length;
IntHashtableEntry oldTable[] = table;
int newCapacity = oldCapacity * 2 + 1;
IntHashtableEntry newTable[] = new IntHashtableEntry[newCapacity];
threshold = (int) (newCapacity * loadFactor);
table = newTable;
for (int i = oldCapacity; i-- > 0;) {
for (IntHashtableEntry old = oldTable[i]; old != null;) {
IntHashtableEntry e = old;
old = old.next;
int index = (e.hash & 0x7FFFFFFF) % newCapacity;
e.next = newTable[index];
newTable[index] = e;
}
}
}
public synchronized Object remove(int key) {
IntHashtableEntry tab[] = table;
int hash = key;
int index = (hash & 0x7FFFFFFF) % tab.length;
for (IntHashtableEntry e = tab[index], prev = null; e != null; prev = e, e = e.next) {
if (e.hash == hash && e.key == key) {
if (prev != null)
prev.next = e.next;
else
tab[index] = e.next;
--count;
return e.value;
}
}
return null;
}
public Object remove(Object okey) {
if (!(okey instanceof Integer))
throw new InternalError("key is not an Integer");
Integer ikey = (Integer) okey;
int key = ikey.intValue();
return remove(key);
}
public int size() {
return count;
}
public synchronized String toString() {
int max = size() - 1;
StringBuffer buf = new StringBuffer();
Enumeration k = keys();
Enumeration e = elements();
buf.append("{");
for (int i = 0; i <= max; ++i) {
String s1 = k.nextElement().toString();
String s2 = e.nextElement().toString();
buf.append(s1 + "=" + s2);
if (i < max)
buf.append(", ");
}
buf.append("}");
return buf.toString();
}
}
class IntHashtableEnumerator implements Enumeration {
boolean keys;
int index;
IntHashtableEntry table[];
IntHashtableEntry entry;
IntHashtableEnumerator(IntHashtableEntry table[], boolean keys) {
this.table = table;
this.keys = keys;
this.index = table.length;
}
public boolean hasMoreElements() {
if (entry != null)
return true;
while (index-- > 0)
if ((entry = table[index]) != null)
return true;
return false;
}
public Object nextElement() {
if (entry == null)
while ((index-- > 0) && ((entry = table[index]) == null)) ;
if (entry != null) {
IntHashtableEntry e = entry;
entry = e.next;
return keys ? new Integer(e.key) : e.value;
}
throw new NoSuchElementException("IntHashtableEnumerator");
}
}
class TransparentFilter extends RGBImageFilter {
int transparentRGB;
public TransparentFilter(Color color) {
transparentRGB = color.getRGB() & 0xFFFFFF;
canFilterIndexColorModel = true;
}
public int filterRGB(int x, int y, int rgb) {
if ((rgb & 0xFFFFFF) == transparentRGB)
return 0;
return rgb;
}
}
/// Constructor.
// @param producer The ImageProducer to encode.
// @param out The stream to write the bytes to.
private GifEncoder(ImageProducer producer, OutputStream out) throws IOException {
this.producer = producer;
this.out = out;
}
/**
* Constructor
* @param img The image to encode.
* @param out The stream to write the bytes to.
*/
public GifEncoder(Image img, OutputStream out) throws IOException {
this(img.getSource(), out);
}
/**
* Constructor from Image with interlace setting.
* @param img The image to encode.
* @param out The stream to write the GIF to.
* @param interlace Whether to interlace.
*/
public GifEncoder(Image img, OutputStream out, boolean interlace) throws IOException {
this(img, out);
this.interlace = interlace;
}
/** Constructor from Image with interlace setting.
* @param img The image to encode.
* @param out The stream to write the GIF to.
* @param interlace Whether to interlace.
* @param transparentColor The color to use for transparency
*/
public GifEncoder(Image img, OutputStream out, boolean interlace, Color transparentColor) throws IOException {
RGBImageFilter f = new TransparentFilter(transparentColor);
this.producer = new FilteredImageSource(img.getSource(), f);
this.out = out;
this.interlace = interlace;
}
// Bump the "curx" and "cury" to point to the next pixel
void BumpPixel() {
// Bump the current X position
++curx;
// If we are at the end of a scan line, set curx back to the beginning
// If we are interlaced, bump the cury to the appropriate spot,
// otherwise, just increment it.
if (curx == Width) {
curx = 0;
if (!Interlace)
++cury;
else {
switch (Pass) {
case 0:
cury += 8;
if (cury >= Height) {
++Pass;
cury = 4;
}
break;
case 1:
cury += 8;
if (cury >= Height) {
++Pass;
cury = 2;
}
break;
case 2:
cury += 4;
if (cury >= Height) {
++Pass;
cury = 1;
}
break;
case 3:
cury += 2;
break;
}
}
}
}
// Set up the "byte output" routine
void char_init() {
a_count = 0;
}
// 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;
char_init();
ent = GIFNextPixel();
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 = GIFNextPixel()) != 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);
}
// Our own methods.
/**
* Call this method after initialization to do the encoding
*/
public synchronized void encode() throws IOException {
encoding = true;
iox = null;
producer.startProduction(this);
while (encoding)
try {
wait();
} catch (InterruptedException e) {
}
if (iox != null)
throw iox;
}
void encodeDone() throws IOException {
int transparentIndex = -1;
int transparentRgb = -1;
// Put all the pixels into a hash table.
colorHash = new IntHashtable();
int index = 0;
for (int row = 0; row < height; ++row) {
for (int col = 0; col < width; ++col) {
int rgb = rgbPixels[row][col];
boolean isTransparent = ((rgb >>> 24) < 0x80);
if (isTransparent) {
if (transparentIndex < 0) {
// First transparent color; remember it.
transparentIndex = index;
transparentRgb = rgb;
} else if (rgb != transparentRgb) {
// A second transparent color; replace it with
// the first one.
rgbPixels[row][col] = rgb = transparentRgb;
}
}
gifHashitem item =
(gifHashitem) colorHash.get(rgb);
if (item == null) {
if (index >= 256)
throw new IOException("too many colors for a GIF");
item = new gifHashitem(
rgb, 1, index, isTransparent);
++index;
colorHash.put(rgb, item);
} else
++item.count;
}
}
// Figure out how many bits to use.
int logColors;
if (index <= 2)
logColors = 1;
else if (index <= 4)
logColors = 2;
else if (index <= 16)
logColors = 4;
else
logColors = 8;
// Turn colors into colormap entries.
int mapSize = 1 << logColors;
byte[] reds = new byte[mapSize];
byte[] grns = new byte[mapSize];
byte[] blus = new byte[mapSize];
for (Enumeration e = colorHash.elements(); e.hasMoreElements();) {
gifHashitem item = (gifHashitem) e.nextElement();
reds[item.index] = (byte) ((item.rgb >> 16) & 0xff);
grns[item.index] = (byte) ((item.rgb >> 8) & 0xff);
blus[item.index] = (byte) (item.rgb & 0xff);
}
GIFEncode(
out, width, height, interlace, (byte) 0, transparentIndex,
logColors, reds, grns, blus);
}
private void encodeFinish() throws IOException {
if (accumulate) {
encodePixels(0, 0, width, height, accumulator, 0, width);
accumulator = null;
accumulate = false;
}
}
void encodePixels(
int x, int y, int w, int h, int[] rgbPixels, int off, int scansize)
throws IOException {
// Save the pixels.
for (int row = 0; row < h; ++row)
System.arraycopy(
rgbPixels, row * scansize + off,
this.rgbPixels[y + row], x, w);
}
private void encodePixelsWrapper(
int x, int y, int w, int h, int[] rgbPixels, int off, int scansize)
throws IOException {
if (!started) {
started = true;
encodeStart(width, height);
if ((hintflags & TOPDOWNLEFTRIGHT) == 0) {
accumulate = true;
accumulator = new int[width * height];
}
}
if (accumulate)
for (int row = 0; row < h; ++row)
System.arraycopy(
rgbPixels, row * scansize + off,
accumulator, (y + row) * width + x,
w);
else
encodePixels(x, y, w, h, rgbPixels, off, scansize);
}
void encodeStart(int width, int height) throws IOException {
this.width = width;
this.height = height;
rgbPixels = new int[height][width];
}
// 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;
}
}
byte GetPixel(int x, int y) throws IOException {
gifHashitem item =
(gifHashitem) colorHash.get(rgbPixels[y][x]);
if (item == null)
throw new IOException("color not found");
return (byte) item.index;
}
void GIFEncode(
OutputStream outs, int Width, int Height, boolean Interlace, byte Background, int Transparent, int BitsPerPixel, byte[] Red, byte[] Green, byte[] Blue)
throws IOException {
byte B;
int LeftOfs, TopOfs;
int ColorMapSize;
int InitCodeSize;
int i;
this.Width = Width;
this.Height = Height;
this.Interlace = Interlace;
ColorMapSize = 1 << BitsPerPixel;
LeftOfs = TopOfs = 0;
// Calculate number of bits we are expecting
CountDown = Width * Height;
// Indicate which pass we are on (if interlace)
Pass = 0;
// The initial code size
if (BitsPerPixel <= 1)
InitCodeSize = 2;
else
InitCodeSize = BitsPerPixel;
// Set up the current x and y position
curx = 0;
cury = 0;
// Write the Magic header
writeString(outs, "GIF89a");
// Write out the screen width and height
Putword(Width, outs);
Putword(Height, outs);
// Indicate that there is a global colour map
B = (byte) 0x80; // Yes, there is a color map
// OR in the resolution
B |= (byte) ((8 - 1) << 4);
// Not sorted
// OR in the Bits per Pixel
B |= (byte) ((BitsPerPixel - 1));
// Write it out
Putbyte(B, outs);
// Write out the Background colour
Putbyte(Background, outs);
// Pixel aspect ratio - 1:1.
//Putbyte( (byte) 49, outs );
// Java"s GIF reader currently has a bug, if the aspect ratio byte is
// not zero it throws an ImageFormatException. It doesn"t know that
// 49 means a 1:1 aspect ratio. Well, whatever, zero works with all
// the other decoders I"ve tried so it probably doesn"t hurt.
Putbyte((byte) 0, outs);
// Write out the Global Colour Map
for (i = 0; i < ColorMapSize; ++i) {
Putbyte(Red[i], outs);
Putbyte(Green[i], outs);
Putbyte(Blue[i], outs);
}
// Write out extension for transparent colour index, if necessary.
if (Transparent != -1) {
Putbyte((byte) "!", outs);
Putbyte((byte) 0xf9, outs);
Putbyte((byte) 4, outs);
Putbyte((byte) 1, outs);
Putbyte((byte) 0, outs);
Putbyte((byte) 0, outs);
Putbyte((byte) Transparent, outs);
Putbyte((byte) 0, outs);
}
// Write an Image separator
Putbyte((byte) ",", outs);
// Write the Image header
Putword(LeftOfs, outs);
Putword(TopOfs, outs);
Putword(Width, outs);
Putword(Height, outs);
// Write out whether or not the image is interlaced
if (Interlace)
Putbyte((byte) 0x40, outs);
else
Putbyte((byte) 0x00, outs);
// Write out the initial code size
Putbyte((byte) InitCodeSize, outs);
// Go and actually compress the data
compress(InitCodeSize + 1, outs);
// Write out a Zero-length packet (to end the series)
Putbyte((byte) 0, outs);
// Write the GIF file terminator
Putbyte((byte) ";", outs);
}
// Return the next pixel from the image
int GIFNextPixel() throws IOException {
byte r;
if (CountDown == 0)
return EOF;
--CountDown;
r = GetPixel(curx, cury);
BumpPixel();
return r & 0xff;
}
public void imageComplete(int status) {
producer.removeConsumer(this);
if (status == ImageConsumer.IMAGEABORTED)
iox = new IOException("image aborted");
else {
try {
encodeFinish();
encodeDone();
} catch (IOException e) {
iox = e;
}
}
stop();
}
final int MAXCODE(int n_bits) {
return (1 << n_bits) - 1;
}
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);
}
}
// Write out a byte to the GIF file
void Putbyte(byte b, OutputStream outs) throws IOException {
outs.write(b);
}
// Write out a word to the GIF file
void Putword(int w, OutputStream outs) throws IOException {
Putbyte((byte) (w & 0xff), outs);
Putbyte((byte) ((w >> 8) & 0xff), outs);
}
public void setColorModel(ColorModel model) {
// Ignore.
}
// Methods from ImageConsumer.
public void setDimensions(int width, int height) {
this.width = width;
this.height = height;
}
public void setHints(int hintflags) {
this.hintflags = hintflags;
}
public void setPixels(
int x, int y, int w, int h, ColorModel model, byte[] pixels,
int off, int scansize) {
int[] rgbPixels = new int[w];
for (int row = 0; row < h; ++row) {
int rowOff = off + row * scansize;
for (int col = 0; col < w; ++col)
rgbPixels[col] = model.getRGB(pixels[rowOff + col] & 0xff);
try {
encodePixelsWrapper(x, y + row, w, 1, rgbPixels, 0, w);
} catch (IOException e) {
iox = e;
stop();
return;
}
}
}
public void setPixels(
int x, int y, int w, int h, ColorModel model, int[] pixels,
int off, int scansize) {
if (model == rgbModel) {
try {
encodePixelsWrapper(x, y, w, h, pixels, off, scansize);
} catch (IOException e) {
iox = e;
stop();
return;
}
} else {
int[] rgbPixels = new int[w];
for (int row = 0; row < h; ++row) {
int rowOff = off + row * scansize;
for (int col = 0; col < w; ++col)
rgbPixels[col] = model.getRGB(pixels[rowOff + col]);
try {
encodePixelsWrapper(x, y + row, w, 1, rgbPixels, 0, w);
} catch (IOException e) {
iox = e;
stop();
return;
}
}
}
}
public void setProperties(Hashtable props) {
this.props = props;
}
private synchronized void stop() {
encoding = false;
notifyAll();
}
static void writeString(OutputStream out, String str) throws IOException {
byte[] buf = str.getBytes();
out.write(buf);
}
}
</source>
GIFEncoder is a class which takes an image and saves it to a stream using the GIF file format
<source lang="java"> /*
* @(#)GIFEncoder.java 0.90 4/21/96 Adam Doppelt */
import java.io.*; import java.awt.*; import java.awt.image.*; /**
* GIFEncoder is a class which takes an image and saves it to a stream * using the GIF file format ( */
public class GIFEncoder {
short width_, height_; int numColors_; byte pixels_[], colors_[]; ScreenDescriptor sd_; ImageDescriptor id_;
/**
* Construct a GIFEncoder. The constructor will convert the image to
* an indexed color array. This may take some time.<P>
*
* @param image The image to encode. The image must be
* completely loaded.
* @exception AWTException Will be thrown if the pixel grab fails. This
* can happen if Java runs out of memory. It may also indicate that the image
* contains more than 256 colors.
* */
public GIFEncoder(Image image) throws AWTException {
width_ = (short)image.getWidth(null);
height_ = (short)image.getHeight(null);
int values[] = new int[width_ * height_];
PixelGrabber grabber = new PixelGrabber(
image, 0, 0, width_, height_, values, 0, width_);
try {
if(grabber.grabPixels() != true)
throw new AWTException("Grabber returned false: " +
grabber.status());
}
catch (InterruptedException e) { ; }
byte r[][] = new byte[width_][height_];
byte g[][] = new byte[width_][height_];
byte b[][] = new byte[width_][height_];
int index = 0;
for (int y = 0; y < height_; ++y)
for (int x = 0; x < width_; ++x) {
r[x][y] = (byte)((values[index] >> 16) & 0xFF);
g[x][y] = (byte)((values[index] >> 8) & 0xFF);
b[x][y] = (byte)((values[index]) & 0xFF);
++index;
}
ToIndexedColor(r, g, b);
}
/**
* Construct a GIFEncoder. The constructor will convert the image to
* an indexed color array. This may take some time.<P>
*
* Each array stores intensity values for the image. In other words,
* r[x][y] refers to the red intensity of the pixel at column x, row
* y.<P>
*
* @param r An array containing the red intensity values.
* @param g An array containing the green intensity values.
* @param b An array containing the blue intensity values.
*
* @exception AWTException Will be thrown if the image contains more than
* 256 colors.
* */
public GIFEncoder(byte r[][], byte g[][], byte b[][]) throws AWTException {
width_ = (short)(r.length);
height_ = (short)(r[0].length);
ToIndexedColor(r, g, b);
}
/**
* Writes the image out to a stream in the GIF file format. This will
* be a single GIF87a image, non-interlaced, with no background color.
* This may take some time.<P>
*
* @param output The stream to output to. This should probably be a
* buffered stream.
*
* @exception IOException Will be thrown if a write operation fails.
* */
public void Write(OutputStream output) throws IOException {
BitUtils.WriteString(output, "GIF87a");
ScreenDescriptor sd = new ScreenDescriptor(width_, height_,
numColors_);
sd.Write(output);
output.write(colors_, 0, colors_.length);
ImageDescriptor id = new ImageDescriptor(width_, height_, ",");
id.Write(output);
byte codesize = BitUtils.BitsNeeded(numColors_);
if (codesize == 1)
++codesize;
output.write(codesize);
LZWCompressor.LZWCompress(output, codesize, pixels_);
output.write(0);
id = new ImageDescriptor((byte)0, (byte)0, ";");
id.Write(output);
output.flush();
}
void ToIndexedColor(byte r[][], byte g[][],
byte b[][]) throws AWTException {
pixels_ = new byte[width_ * height_];
colors_ = new byte[256 * 3];
int colornum = 0;
for (int x = 0; x < width_; ++x) {
for (int y = 0; y < height_; ++y) {
int search;
for (search = 0; search < colornum; ++search)
if (colors_[search * 3] == r[x][y] &&
colors_[search * 3 + 1] == g[x][y] &&
colors_[search * 3 + 2] == b[x][y])
break;
if (search > 255)
throw new AWTException("Too many colors.");
pixels_[y * width_ + x] = (byte)search;
if (search == colornum) {
colors_[search * 3] = r[x][y];
colors_[search * 3 + 1] = g[x][y];
colors_[search * 3 + 2] = b[x][y];
++colornum;
}
}
}
numColors_ = 1 << BitUtils.BitsNeeded(colornum);
byte copy[] = new byte[numColors_ * 3];
System.arraycopy(colors_, 0, copy, 0, numColors_ * 3);
colors_ = copy;
}
} class BitFile {
OutputStream output_;
byte buffer_[];
int index_, bitsLeft_;
public BitFile(OutputStream output) {
output_ = output;
buffer_ = new byte[256];
index_ = 0;
bitsLeft_ = 8;
}
public void Flush() throws IOException {
int numBytes = index_ + (bitsLeft_ == 8 ? 0 : 1);
if (numBytes > 0) {
output_.write(numBytes);
output_.write(buffer_, 0, numBytes);
buffer_[0] = 0;
index_ = 0;
bitsLeft_ = 8;
}
}
public void WriteBits(int bits, int numbits) throws IOException {
int bitsWritten = 0;
int numBytes = 255;
do {
if ((index_ == 254 && bitsLeft_ == 0) || index_ > 254) {
output_.write(numBytes);
output_.write(buffer_, 0, numBytes);
buffer_[0] = 0;
index_ = 0;
bitsLeft_ = 8;
}
if (numbits <= bitsLeft_) {
buffer_[index_] |= (bits & ((1 << numbits) - 1)) <<
(8 - bitsLeft_);
bitsWritten += numbits;
bitsLeft_ -= numbits;
numbits = 0;
}
else {
buffer_[index_] |= (bits & ((1 << bitsLeft_) - 1)) <<
(8 - bitsLeft_);
bitsWritten += bitsLeft_;
bits >>= bitsLeft_;
numbits -= bitsLeft_;
buffer_[++index_] = 0;
bitsLeft_ = 8;
}
} while (numbits != 0);
}
} class LZWStringTable {
private final static int RES_CODES = 2;
private final static short HASH_FREE = (short)0xFFFF;
private final static short NEXT_FIRST = (short)0xFFFF;
private final static int MAXBITS = 12;
private final static int MAXSTR = (1 << MAXBITS);
private final static short HASHSIZE = 9973;
private final static short HASHSTEP = 2039;
byte strChr_[];
short strNxt_[];
short strHsh_[];
short numStrings_;
public LZWStringTable() {
strChr_ = new byte[MAXSTR];
strNxt_ = new short[MAXSTR];
strHsh_ = new short[HASHSIZE];
}
public int AddCharString(short index, byte b) {
int hshidx;
if (numStrings_ >= MAXSTR)
return 0xFFFF;
hshidx = Hash(index, b);
while (strHsh_[hshidx] != HASH_FREE)
hshidx = (hshidx + HASHSTEP) % HASHSIZE;
strHsh_[hshidx] = numStrings_;
strChr_[numStrings_] = b;
strNxt_[numStrings_] = (index != HASH_FREE) ? index : NEXT_FIRST;
return numStrings_++;
}
public short FindCharString(short index, byte b) {
int hshidx, nxtidx;
if (index == HASH_FREE)
return b;
hshidx = Hash(index, b);
while ((nxtidx = strHsh_[hshidx]) != HASH_FREE) {
if (strNxt_[nxtidx] == index && strChr_[nxtidx] == b)
return (short)nxtidx;
hshidx = (hshidx + HASHSTEP) % HASHSIZE;
}
return (short)0xFFFF;
}
public void ClearTable(int codesize) {
numStrings_ = 0;
for (int q = 0; q < HASHSIZE; q++) {
strHsh_[q] = HASH_FREE;
}
int w = (1 << codesize) + RES_CODES;
for (int q = 0; q < w; q++)
AddCharString((short)0xFFFF, (byte)q);
}
static public int Hash(short index, byte lastbyte) {
return ((int)((short)(lastbyte << 8) ^ index) & 0xFFFF) % HASHSIZE;
}
} class LZWCompressor {
public static void LZWCompress(OutputStream output, int codesize,
byte toCompress[]) throws IOException {
byte c;
short index;
int clearcode, endofinfo, numbits, limit, errcode;
short prefix = (short)0xFFFF;
BitFile bitFile = new BitFile(output);
LZWStringTable strings = new LZWStringTable();
clearcode = 1 << codesize;
endofinfo = clearcode + 1;
numbits = codesize + 1;
limit = (1 << numbits) - 1;
strings.ClearTable(codesize);
bitFile.WriteBits(clearcode, numbits);
for (int loop = 0; loop < toCompress.length; ++loop) {
c = toCompress[loop];
if ((index = strings.FindCharString(prefix, c)) != -1)
prefix = index;
else {
bitFile.WriteBits(prefix, numbits);
if (strings.AddCharString(prefix, c) > limit) {
if (++numbits > 12) {
bitFile.WriteBits(clearcode, numbits - 1);
strings.ClearTable(codesize);
numbits = codesize + 1;
}
limit = (1 << numbits) - 1;
}
prefix = (short)((short)c & 0xFF);
}
}
if (prefix != -1)
bitFile.WriteBits(prefix, numbits);
bitFile.WriteBits(endofinfo, numbits);
bitFile.Flush();
}
} class ScreenDescriptor {
public short localScreenWidth_, localScreenHeight_;
private byte byte_;
public byte backgroundColorIndex_, pixelAspectRatio_;
public ScreenDescriptor(short width, short height, int numColors) {
localScreenWidth_ = width;
localScreenHeight_ = height;
SetGlobalColorTableSize((byte)(BitUtils.BitsNeeded(numColors) - 1));
SetGlobalColorTableFlag((byte)1);
SetSortFlag((byte)0);
SetColorResolution((byte)7);
backgroundColorIndex_ = 0;
pixelAspectRatio_ = 0;
}
public void Write(OutputStream output) throws IOException {
BitUtils.WriteWord(output, localScreenWidth_);
BitUtils.WriteWord(output, localScreenHeight_);
output.write(byte_);
output.write(backgroundColorIndex_);
output.write(pixelAspectRatio_);
}
public void SetGlobalColorTableSize(byte num) {
byte_ |= (num & 7);
}
public void SetSortFlag(byte num) {
byte_ |= (num & 1) << 3;
}
public void SetColorResolution(byte num) {
byte_ |= (num & 7) << 4;
}
public void SetGlobalColorTableFlag(byte num) {
byte_ |= (num & 1) << 7;
}
} class ImageDescriptor {
public byte separator_;
public short leftPosition_, topPosition_, width_, height_;
private byte byte_;
public ImageDescriptor(short width, short height, char separator) {
separator_ = (byte)separator;
leftPosition_ = 0;
topPosition_ = 0;
width_ = width;
height_ = height;
SetLocalColorTableSize((byte)0);
SetReserved((byte)0);
SetSortFlag((byte)0);
SetInterlaceFlag((byte)0);
SetLocalColorTableFlag((byte)0);
}
public void Write(OutputStream output) throws IOException {
output.write(separator_);
BitUtils.WriteWord(output, leftPosition_);
BitUtils.WriteWord(output, topPosition_);
BitUtils.WriteWord(output, width_);
BitUtils.WriteWord(output, height_);
output.write(byte_);
}
public void SetLocalColorTableSize(byte num) {
byte_ |= (num & 7);
}
public void SetReserved(byte num) {
byte_ |= (num & 3) << 3;
}
public void SetSortFlag(byte num) {
byte_ |= (num & 1) << 5;
}
public void SetInterlaceFlag(byte num) {
byte_ |= (num & 1) << 6;
}
public void SetLocalColorTableFlag(byte num) {
byte_ |= (num & 1) << 7;
}
} class BitUtils {
public static byte BitsNeeded(int n) {
byte ret = 1;
if (n-- == 0)
return 0;
while ((n >>= 1) != 0)
++ret;
return ret;
}
public static void WriteWord(OutputStream output,
short w) throws IOException {
output.write(w & 0xFF);
output.write((w >> 8) & 0xFF);
}
static void WriteString(OutputStream output,
String string) throws IOException {
for (int loop = 0; loop < string.length(); ++loop)
output.write((byte)(string.charAt(loop)));
}
}
</source>
Gif Encoder - writes out an image as a GIF.
<source lang="java">
import java.awt.Image; import java.awt.image.ColorModel; import java.awt.image.IndexColorModel; import java.awt.image.PixelGrabber; import java.io.IOException; import java.io.OutputStream;
/** GifEncoder - writes out an image as a GIF.
* * Transparency handling and variable bit size courtesy of Jack Palevich. * * Copyright (C) 1996 by Jef Poskanzer <jef@acme.ru>. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS"" AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * Visit the ACME Labs Java page for up-to-date versions of this and other * fine Java utilities: http://www.acme.ru/java/ */
public class GifEncoder {
private boolean interlace = false;
private int width, height;
private byte[] pixels;
private byte[] r, g, b; // the color look-up table
private int pixelIndex;
private int numPixels;
private int transparentPixel = -1; // hpm
/**
* Constructs a new GifEncoder.
* @param width The image width.
* @param height The image height.
* @param pixels The pixel data.
* @param r The red look-up table.
* @param g The green look-up table.
* @param b The blue look-up table.
*/
public GifEncoder(int width, int height, byte[] pixels, byte[] r, byte[] g, byte[] b) {
this.width = width;
this.height = height;
this.pixels = pixels;
this.r = r;
this.g = g;
this.b = b;
interlace = false;
pixelIndex = 0;
numPixels = width * height;
}
/** Constructs a new GifEncoder using an 8-bit AWT Image.
The image is assumed to be fully loaded. */
public GifEncoder(Image img) {
width = img.getWidth(null);
height = img.getHeight(null);
pixels = new byte[width * height];
PixelGrabber pg = new PixelGrabber(img, 0, 0, width, height, false);
try {
pg.grabPixels();
} catch (InterruptedException e) {
System.err.println(e);
}
ColorModel cm = pg.getColorModel();
if (cm instanceof IndexColorModel) {
pixels = (byte[]) (pg.getPixels());
// hpm
IndexColorModel icm = (IndexColorModel) cm;
setTransparentPixel(icm.getTransparentPixel());
} else
throw new IllegalArgumentException("IMAGE_ERROR");
IndexColorModel m = (IndexColorModel) cm;
int mapSize = m.getMapSize();
r = new byte[mapSize];
g = new byte[mapSize];
b = new byte[mapSize];
m.getReds(r);
m.getGreens(g);
m.getBlues(b);
interlace = false;
pixelIndex = 0;
numPixels = width * height;
}
/** Saves the image as a GIF file. */
public void write(OutputStream out) throws IOException {
// Figure out how many bits to use.
int numColors = r.length;
int BitsPerPixel;
if (numColors <= 2)
BitsPerPixel = 1;
else if (numColors <= 4)
BitsPerPixel = 2;
else if (numColors <= 16)
BitsPerPixel = 4;
else
BitsPerPixel = 8;
int ColorMapSize = 1 << BitsPerPixel;
byte[] reds = new byte[ColorMapSize];
byte[] grns = new byte[ColorMapSize];
byte[] blus = new byte[ColorMapSize];
for (int i = 0; i < numColors; i++) {
reds[i] = r[i];
grns[i] = g[i];
blus[i] = b[i];
}
// hpm
GIFEncode(out, width, height, interlace, (byte) 0, getTransparentPixel(), BitsPerPixel, reds, grns, blus);
}
// hpm
public void setTransparentPixel(int pixel) {
transparentPixel = pixel;
}
// hpm
public int getTransparentPixel() {
return transparentPixel;
}
static void writeString(OutputStream out, String str) throws IOException {
byte[] buf = str.getBytes();
out.write(buf);
}
// Adapted from ppmtogif, which is based on GIFENCOD by David
// Rowley <mgardi@watdscu.waterloo.edu>. Lempel-Zim compression
// based on "compress".
int Width, Height;
boolean Interlace;
void GIFEncode(OutputStream outs, int Width, int Height, boolean Interlace,
byte Background, int Transparent, int BitsPerPixel, byte[] Red,
byte[] Green, byte[] Blue) throws IOException {
byte B;
int LeftOfs, TopOfs;
int ColorMapSize;
int InitCodeSize;
int i;
this.Width = Width;
this.Height = Height;
this.Interlace = Interlace;
ColorMapSize = 1 << BitsPerPixel;
LeftOfs = TopOfs = 0;
// The initial code size
if (BitsPerPixel <= 1)
InitCodeSize = 2;
else
InitCodeSize = BitsPerPixel;
// Write the Magic header
writeString(outs, "GIF89a");
// Write out the screen width and height
Putword(Width, outs);
Putword(Height, outs);
// Indicate that there is a global colour map
B = (byte) 0x80; // Yes, there is a color map
// OR in the resolution
B |= (byte) ((8 - 1) << 4);
// Not sorted
// OR in the Bits per Pixel
B |= (byte) ((BitsPerPixel - 1));
// Write it out
Putbyte(B, outs);
// Write out the Background colour
Putbyte(Background, outs);
// Pixel aspect ratio - 1:1.
//Putbyte( (byte) 49, outs );
// Java"s GIF reader currently has a bug, if the aspect ratio byte is
// not zero it throws an ImageFormatException. It doesn"t know that
// 49 means a 1:1 aspect ratio. Well, whatever, zero works with all
// the other decoders I"ve tried so it probably doesn"t hurt.
Putbyte((byte) 0, outs);
// Write out the Global Colour Map
for (i = 0; i < ColorMapSize; ++i) {
Putbyte(Red[i], outs);
Putbyte(Green[i], outs);
Putbyte(Blue[i], outs);
}
// Write out extension for transparent colour index, if necessary.
if (Transparent != -1) {
Putbyte((byte) "!", outs);
Putbyte((byte) 0xf9, outs);
Putbyte((byte) 4, outs);
Putbyte((byte) 1, outs);
Putbyte((byte) 0, outs);
Putbyte((byte) 0, outs);
Putbyte((byte) Transparent, outs);
Putbyte((byte) 0, outs);
}
// Write an Image separator
Putbyte((byte) ",", outs);
// Write the Image header
Putword(LeftOfs, outs);
Putword(TopOfs, outs);
Putword(Width, outs);
Putword(Height, outs);
// Write out whether or not the image is interlaced
if (Interlace)
Putbyte((byte) 0x40, outs);
else
Putbyte((byte) 0x00, outs);
// Write out the initial code size
Putbyte((byte) InitCodeSize, outs);
// Go and actually compress the data
compress(InitCodeSize + 1, outs);
// Write out a Zero-length packet (to end the series)
Putbyte((byte) 0, outs);
// Write the GIF file terminator
Putbyte((byte) ";", outs);
}
static final int EOF = -1;
// Return the next pixel from the image
int GIFNextPixel() throws IOException {
if (pixelIndex == numPixels)
return EOF;
else
return ((byte[]) pixels)[pixelIndex++] & 0xff;
}
// Write out a word to the GIF file
void Putword(int w, OutputStream outs) throws IOException {
Putbyte((byte) (w & 0xff), outs);
Putbyte((byte) ((w >> 8) & 0xff), outs);
}
// Write out a byte to the GIF file
void Putbyte(byte b, OutputStream outs) throws IOException {
outs.write(b);
}
// 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
final int MAXCODE(int n_bits) {
return (1 << n_bits) - 1;
}
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;
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;
char_init();
ent = GIFNextPixel();
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 = GIFNextPixel()) != 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);
}
// 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 };
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);
}
}
// 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;
}
// GIF Specific routines
// Number of characters so far in this "packet"
int a_count;
// Set up the "byte output" routine
void char_init() {
a_count = 0;
}
// Define the storage for the packet accumulator
byte[] accum = new byte[256];
// 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);
}
// 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;
}
}
} class GifEncoderHashitem {
public int rgb;
public int count;
public int index;
public boolean isTransparent;
public GifEncoderHashitem(int rgb, int count, int index,
boolean isTransparent) {
this.rgb = rgb;
this.count = count;
this.index = index;
this.isTransparent = isTransparent;
}
}
</source>
Gif file Encoder
<source lang="java"> import java.awt.AlphaComposite; import java.awt.Color; import java.awt.Dimension; import java.awt.Graphics2D; import java.awt.Rectangle; import java.awt.image.BufferedImage; import java.awt.image.DataBufferInt; import java.io.BufferedInputStream; import java.io.FileInputStream; import java.io.IOException; import java.io.InputStream; import java.net.URL; import java.util.ArrayList; /**
* Class GifDecoder - Decodes a GIF file into one or more frames.*
*
* Example:
* GifDecoder d = new GifDecoder();
* d.read("sample.gif");
* int n = d.getFrameCount();
* for (int i = 0; i < n; i++) {
* BufferedImage frame = d.getFrame(i); // frame i
* int t = d.getDelay(i); // display duration of frame in milliseconds
* // do something with frame
* }
*
* * No copyright asserted on the source code of this class. May be used for any * purpose, however, refer to the Unisys LZW patent for any additional * restrictions. Please forward any corrections to kweiner@fmsware.ru. * * @author Kevin Weiner, FM Software; LZW decoder adapted from John Cristy"s * ImageMagick. * @version 1.03 November 2003 * */
public class GifDecoder {
/**
* File read status: No errors.
*/
public static final int STATUS_OK = 0;
/**
* File read status: Error decoding file (may be partially decoded)
*/
public static final int STATUS_FORMAT_ERROR = 1;
/**
* File read status: Unable to open source.
*/
public static final int STATUS_OPEN_ERROR = 2;
protected BufferedInputStream in;
protected int status;
protected int width; // full image width
protected int height; // full image height
protected boolean gctFlag; // global color table used
protected int gctSize; // size of global color table
protected int loopCount = 1; // iterations; 0 = repeat forever
protected int[] gct; // global color table
protected int[] lct; // local color table
protected int[] act; // active color table
protected int bgIndex; // background color index
protected int bgColor; // background color
protected int lastBgColor; // previous bg color
protected int pixelAspect; // pixel aspect ratio
protected boolean lctFlag; // local color table flag
protected boolean interlace; // interlace flag
protected int lctSize; // local color table size
protected int ix, iy, iw, ih; // current image rectangle
protected Rectangle lastRect; // last image rect
protected BufferedImage image; // current frame
protected BufferedImage lastImage; // previous frame
protected byte[] block = new byte[256]; // current data block
protected int blockSize = 0; // block size
// last graphic control extension info
protected int dispose = 0;
// 0=no action; 1=leave in place; 2=restore to bg; 3=restore to prev
protected int lastDispose = 0;
protected boolean transparency = false; // use transparent color
protected int delay = 0; // delay in milliseconds
protected int transIndex; // transparent color index
protected static final int MaxStackSize = 4096;
// max decoder pixel stack size
// LZW decoder working arrays
protected short[] prefix;
protected byte[] suffix;
protected byte[] pixelStack;
protected byte[] pixels;
protected ArrayList frames; // frames read from current file
protected int frameCount;
static class GifFrame {
public GifFrame(BufferedImage im, int del) {
image = im;
delay = del;
}
public BufferedImage image;
public int delay;
}
/**
* Gets display duration for specified frame.
*
* @param n
* int index of frame
* @return delay in milliseconds
*/
public int getDelay(int n) {
//
delay = -1;
if ((n >= 0) && (n < frameCount)) {
delay = ((GifFrame) frames.get(n)).delay;
}
return delay;
}
/**
* Gets the number of frames read from file.
*
* @return frame count
*/
public int getFrameCount() {
return frameCount;
}
/**
* Gets the first (or only) image read.
*
* @return BufferedImage containing first frame, or null if none.
*/
public BufferedImage getImage() {
return getFrame(0);
}
/**
* Gets the "Netscape" iteration count, if any. A count of 0 means repeat
* indefinitiely.
*
* @return iteration count if one was specified, else 1.
*/
public int getLoopCount() {
return loopCount;
}
/**
* Creates new frame image from current data (and previous frames as specified
* by their disposition codes).
*/
protected void setPixels() {
// expose destination image"s pixels as int array
int[] dest = ((DataBufferInt) image.getRaster().getDataBuffer()).getData();
// fill in starting image contents based on last image"s dispose code
if (lastDispose > 0) {
if (lastDispose == 3) {
// use image before last
int n = frameCount - 2;
if (n > 0) {
lastImage = getFrame(n - 1);
} else {
lastImage = null;
}
}
if (lastImage != null) {
int[] prev = ((DataBufferInt) lastImage.getRaster().getDataBuffer()).getData();
System.arraycopy(prev, 0, dest, 0, width * height);
// copy pixels
if (lastDispose == 2) {
// fill last image rect area with background color
Graphics2D g = image.createGraphics();
Color c = null;
if (transparency) {
c = new Color(0, 0, 0, 0); // assume background is transparent
} else {
c = new Color(lastBgColor); // use given background color
}
g.setColor(c);
g.setComposite(AlphaComposite.Src); // replace area
g.fill(lastRect);
g.dispose();
}
}
}
// copy each source line to the appropriate place in the destination
int pass = 1;
int inc = 8;
int iline = 0;
for (int i = 0; i < ih; i++) {
int line = i;
if (interlace) {
if (iline >= ih) {
pass++;
switch (pass) {
case 2:
iline = 4;
break;
case 3:
iline = 2;
inc = 4;
break;
case 4:
iline = 1;
inc = 2;
}
}
line = iline;
iline += inc;
}
line += iy;
if (line < height) {
int k = line * width;
int dx = k + ix; // start of line in dest
int dlim = dx + iw; // end of dest line
if ((k + width) < dlim) {
dlim = k + width; // past dest edge
}
int sx = i * iw; // start of line in source
while (dx < dlim) {
// map color and insert in destination
int index = ((int) pixels[sx++]) & 0xff;
int c = act[index];
if (c != 0) {
dest[dx] = c;
}
dx++;
}
}
}
}
/**
* Gets the image contents of frame n.
*
* @return BufferedImage representation of frame, or null if n is invalid.
*/
public BufferedImage getFrame(int n) {
BufferedImage im = null;
if ((n >= 0) && (n < frameCount)) {
im = ((GifFrame) frames.get(n)).image;
}
return im;
}
/**
* Gets image size.
*
* @return GIF image dimensions
*/
public Dimension getFrameSize() {
return new Dimension(width, height);
}
/**
* Reads GIF image from stream
*
* @param BufferedInputStream
* containing GIF file.
* @return read status code (0 = no errors)
*/
public int read(BufferedInputStream is) {
init();
if (is != null) {
in = is;
readHeader();
if (!err()) {
readContents();
if (frameCount < 0) {
status = STATUS_FORMAT_ERROR;
}
}
} else {
status = STATUS_OPEN_ERROR;
}
try {
is.close();
} catch (IOException e) {
}
return status;
}
/**
* Reads GIF image from stream
*
* @param InputStream
* containing GIF file.
* @return read status code (0 = no errors)
*/
public int read(InputStream is) {
init();
if (is != null) {
if (!(is instanceof BufferedInputStream))
is = new BufferedInputStream(is);
in = (BufferedInputStream) is;
readHeader();
if (!err()) {
readContents();
if (frameCount < 0) {
status = STATUS_FORMAT_ERROR;
}
}
} else {
status = STATUS_OPEN_ERROR;
}
try {
is.close();
} catch (IOException e) {
}
return status;
}
/**
* Reads GIF file from specified file/URL source (URL assumed if name contains
* ":/" or "file:")
*
* @param name
* String containing source
* @return read status code (0 = no errors)
*/
public int read(String name) {
status = STATUS_OK;
try {
name = name.trim().toLowerCase();
if ((name.indexOf("file:") >= 0) || (name.indexOf(":/") > 0)) {
URL url = new URL(name);
in = new BufferedInputStream(url.openStream());
} else {
in = new BufferedInputStream(new FileInputStream(name));
}
status = read(in);
} catch (IOException e) {
status = STATUS_OPEN_ERROR;
}
return status;
}
/**
* Decodes LZW image data into pixel array. Adapted from John Cristy"s
* ImageMagick.
*/
protected void decodeImageData() {
int NullCode = -1;
int npix = iw * ih;
int available, clear, code_mask, code_size, end_of_information, in_code, old_code, bits, code, count, i, datum, data_size, first, top, bi, pi;
if ((pixels == null) || (pixels.length < npix)) {
pixels = new byte[npix]; // allocate new pixel array
}
if (prefix == null)
prefix = new short[MaxStackSize];
if (suffix == null)
suffix = new byte[MaxStackSize];
if (pixelStack == null)
pixelStack = new byte[MaxStackSize + 1];
// Initialize GIF data stream decoder.
data_size = read();
clear = 1 << data_size;
end_of_information = clear + 1;
available = clear + 2;
old_code = NullCode;
code_size = data_size + 1;
code_mask = (1 << code_size) - 1;
for (code = 0; code < clear; code++) {
prefix[code] = 0;
suffix[code] = (byte) code;
}
// Decode GIF pixel stream.
datum = bits = count = first = top = pi = bi = 0;
for (i = 0; i < npix;) {
if (top == 0) {
if (bits < code_size) {
// Load bytes until there are enough bits for a code.
if (count == 0) {
// Read a new data block.
count = readBlock();
if (count <= 0)
break;
bi = 0;
}
datum += (((int) block[bi]) & 0xff) << bits;
bits += 8;
bi++;
count--;
continue;
}
// Get the next code.
code = datum & code_mask;
datum >>= code_size;
bits -= code_size;
// Interpret the code
if ((code > available) || (code == end_of_information))
break;
if (code == clear) {
// Reset decoder.
code_size = data_size + 1;
code_mask = (1 << code_size) - 1;
available = clear + 2;
old_code = NullCode;
continue;
}
if (old_code == NullCode) {
pixelStack[top++] = suffix[code];
old_code = code;
first = code;
continue;
}
in_code = code;
if (code == available) {
pixelStack[top++] = (byte) first;
code = old_code;
}
while (code > clear) {
pixelStack[top++] = suffix[code];
code = prefix[code];
}
first = ((int) suffix[code]) & 0xff;
// Add a new string to the string table,
if (available >= MaxStackSize)
break;
pixelStack[top++] = (byte) first;
prefix[available] = (short) old_code;
suffix[available] = (byte) first;
available++;
if (((available & code_mask) == 0) && (available < MaxStackSize)) {
code_size++;
code_mask += available;
}
old_code = in_code;
}
// Pop a pixel off the pixel stack.
top--;
pixels[pi++] = pixelStack[top];
i++;
}
for (i = pi; i < npix; i++) {
pixels[i] = 0; // clear missing pixels
}
}
/**
* Returns true if an error was encountered during reading/decoding
*/
protected boolean err() {
return status != STATUS_OK;
}
/**
* Initializes or re-initializes reader
*/
protected void init() {
status = STATUS_OK;
frameCount = 0;
frames = new ArrayList();
gct = null;
lct = null;
}
/**
* Reads a single byte from the input stream.
*/
protected int read() {
int curByte = 0;
try {
curByte = in.read();
} catch (IOException e) {
status = STATUS_FORMAT_ERROR;
}
return curByte;
}
/**
* Reads next variable length block from input.
*
* @return number of bytes stored in "buffer"
*/
protected int readBlock() {
blockSize = read();
int n = 0;
if (blockSize > 0) {
try {
int count = 0;
while (n < blockSize) {
count = in.read(block, n, blockSize - n);
if (count == -1)
break;
n += count;
}
} catch (IOException e) {
}
if (n < blockSize) {
status = STATUS_FORMAT_ERROR;
}
}
return n;
}
/**
* Reads color table as 256 RGB integer values
*
* @param ncolors
* int number of colors to read
* @return int array containing 256 colors (packed ARGB with full alpha)
*/
protected int[] readColorTable(int ncolors) {
int nbytes = 3 * ncolors;
int[] tab = null;
byte[] c = new byte[nbytes];
int n = 0;
try {
n = in.read(c);
} catch (IOException e) {
}
if (n < nbytes) {
status = STATUS_FORMAT_ERROR;
} else {
tab = new int[256]; // max size to avoid bounds checks
int i = 0;
int j = 0;
while (i < ncolors) {
int r = ((int) c[j++]) & 0xff;
int g = ((int) c[j++]) & 0xff;
int b = ((int) c[j++]) & 0xff;
tab[i++] = 0xff000000 | (r << 16) | (g << 8) | b;
}
}
return tab;
}
/**
* Main file parser. Reads GIF content blocks.
*/
protected void readContents() {
// read GIF file content blocks
boolean done = false;
while (!(done || err())) {
int code = read();
switch (code) {
case 0x2C: // image separator
readImage();
break;
case 0x21: // extension
code = read();
switch (code) {
case 0xf9: // graphics control extension
readGraphicControlExt();
break;
case 0xff: // application extension
readBlock();
String app = "";
for (int i = 0; i < 11; i++) {
app += (char) block[i];
}
if (app.equals("NETSCAPE2.0")) {
readNetscapeExt();
} else
skip(); // don"t care
break;
default: // uninteresting extension
skip();
}
break;
case 0x3b: // terminator
done = true;
break;
case 0x00: // bad byte, but keep going and see what happens
break;
default:
status = STATUS_FORMAT_ERROR;
}
}
}
/**
* Reads Graphics Control Extension values
*/
protected void readGraphicControlExt() {
read(); // block size
int packed = read(); // packed fields
dispose = (packed & 0x1c) >> 2; // disposal method
if (dispose == 0) {
dispose = 1; // elect to keep old image if discretionary
}
transparency = (packed & 1) != 0;
delay = readShort() * 10; // delay in milliseconds
transIndex = read(); // transparent color index
read(); // block terminator
}
/**
* Reads GIF file header information.
*/
protected void readHeader() {
String id = "";
for (int i = 0; i < 6; i++) {
id += (char) read();
}
if (!id.startsWith("GIF")) {
status = STATUS_FORMAT_ERROR;
return;
}
readLSD();
if (gctFlag && !err()) {
gct = readColorTable(gctSize);
bgColor = gct[bgIndex];
}
}
/**
* Reads next frame image
*/
protected void readImage() {
ix = readShort(); // (sub)image position & size
iy = readShort();
iw = readShort();
ih = readShort();
int packed = read();
lctFlag = (packed & 0x80) != 0; // 1 - local color table flag
interlace = (packed & 0x40) != 0; // 2 - interlace flag
// 3 - sort flag
// 4-5 - reserved
lctSize = 2 << (packed & 7); // 6-8 - local color table size
if (lctFlag) {
lct = readColorTable(lctSize); // read table
act = lct; // make local table active
} else {
act = gct; // make global table active
if (bgIndex == transIndex)
bgColor = 0;
}
int save = 0;
if (transparency) {
save = act[transIndex];
act[transIndex] = 0; // set transparent color if specified
}
if (act == null) {
status = STATUS_FORMAT_ERROR; // no color table defined
}
if (err())
return;
decodeImageData(); // decode pixel data
skip();
if (err())
return;
frameCount++;
// create new image to receive frame data
image = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB_PRE);
setPixels(); // transfer pixel data to image
frames.add(new GifFrame(image, delay)); // add image to frame list
if (transparency) {
act[transIndex] = save;
}
resetFrame();
}
/**
* Reads Logical Screen Descriptor
*/
protected void readLSD() {
// logical screen size
width = readShort();
height = readShort();
// packed fields
int packed = read();
gctFlag = (packed & 0x80) != 0; // 1 : global color table flag
// 2-4 : color resolution
// 5 : gct sort flag
gctSize = 2 << (packed & 7); // 6-8 : gct size
bgIndex = read(); // background color index
pixelAspect = read(); // pixel aspect ratio
}
/**
* Reads Netscape extenstion to obtain iteration count
*/
protected void readNetscapeExt() {
do {
readBlock();
if (block[0] == 1) {
// loop count sub-block
int b1 = ((int) block[1]) & 0xff;
int b2 = ((int) block[2]) & 0xff;
loopCount = (b2 << 8) | b1;
}
} while ((blockSize > 0) && !err());
}
/**
* Reads next 16-bit value, LSB first
*/
protected int readShort() {
// read 16-bit value, LSB first
return read() | (read() << 8);
}
/**
* Resets frame state for reading next image.
*/
protected void resetFrame() {
lastDispose = dispose;
lastRect = new Rectangle(ix, iy, iw, ih);
lastImage = image;
lastBgColor = bgColor;
int dispose = 0;
boolean transparency = false;
int delay = 0;
lct = null;
}
/**
* Skips variable length blocks up to and including next zero length block.
*/
protected void skip() {
do {
readBlock();
} while ((blockSize > 0) && !err());
}
}
</source>
GIF Writer
<source lang="java"> import java.awt.image.BufferedImage; import java.io.File; import javax.imageio.ImageIO; public class ImageConverterGIF {
public static void main(String[] args) throws Exception {
String imageFilePath = "C:/myBmp.bmp";
String gifFilePath = "C:/myPic.gif";
File inputFile = new File(imageFilePath);
BufferedImage image = ImageIO.read(inputFile);
File outputFile = new File(gifFilePath);
ImageIO.write(image, "GIF", outputFile);
}
}
</source>
Hide the mouse cursor: use a transparent GIF as the cursor
<source lang="java"> import java.awt.Cursor; import java.awt.Image; import java.awt.Point; import java.awt.Toolkit; import java.awt.image.MemoryImageSource; public class Main {
public static void main(String[] argv) throws Exception {
int[] pixels = new int[16 * 16];
Image image = Toolkit.getDefaultToolkit().createImage(
new MemoryImageSource(16, 16, pixels, 0, 16));
Cursor transparentCursor = Toolkit.getDefaultToolkit().createCustomCursor(
image, new Point(0, 0), "invisibleCursor");
}
}
