Java、JFrame制作录制GIF小工具

和截屏工具类似，选取一块区域截图保存成图片，gif录制就是选取一块区域持续录制，最后保存成gif动画图片。

运行效果

1、选取需要录制的区域（鼠标拖拽选择录制的区域）



2、点击开始按钮开始录制GIF图片（开始录制时，区域边框会闪烁）



3、点击结束按钮保存GIF图片（没错提示就是这么裸露，自己懒得优化）



4、最后生成GIF图片

设计思路

1、如何绘制矩形区域

如何绘制用户可见的矩形区域，这是一个小的难点，你可以在JFrame绘制任意的形状，如何不遮挡屏幕的情况下，再屏幕任何地方选取一块区域呢

a、首先画一个和屏幕一样大的透明JFrame。



来看下上面的一段代码，是显示一个和电脑屏幕一样大的透明窗口。

// 设置窗口无标题部分

this.setUndecorated(true);

// 设置透明背景色，0x01000000 ，01表示透明度

// 这里要注意，不能将窗口设置为00（完全透明），如果设置为完全透明，鼠标将无法聚焦当前窗口，也就无法绘制图形了，这里你可以改成00试试看你就明白了。

this.setBackground(new Color(0x01000000, true));

b、 再监听鼠标拖拽事件，画矩形



上面代码就是画一个矩形，是通过设置label的边框、大小和起点位置来画矩形的

if (sx == -1)  // sx=-1说明是鼠标第一次按下，设置label的位置，也就是矩形的位置

else // 否则是鼠标按下拖拽的过程，只需要设置label的大小即可形成一个绘制矩形的效果

选取矩形区域这里有个BUG，用了你就知道了，懒得改 :）

2、截屏

这个录gif不是说选取区域之后就开始录制了，而是先不停的截取区域的图片保存到临时路径下。



上图代码就是每隔interval毫秒截取屏幕并保存为图片的，截屏保存图片的代码很简单，自己稍微看下就明白了。

这里有个需要注意的地方就是，截取的屏幕是不含鼠标的。但是截图没有鼠标就算了，gif图片肯定记录操作的，没有鼠标怎么行。这里的处理是：每次截屏的时候获取鼠标位置信息，在鼠标所在的位置绘制一个小圆圈即可，如下图代码。



3、保存GIF

保存GIF就比较简单了，网上找的一个GIF工具类AnimatedGifEncoder，不知道哪位大神写的。

代码

大家可以下载源代码，不要积分的

http://download.csdn.net/detail/dingyi4815313/9776746

主界面：GIFCapture.java

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.Insets;
import java.awt.Rectangle;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionListener;
import java.io.File;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.UIManager;
import javax.swing.border.LineBorder;
import javax.swing.filechooser.FileSystemView;

/**
* 屏幕GIF动画录制，有两个较大的问题可以优化（1、保存GIF图片的时间太长。2、保存GIF图片太大），如果你有好的建议可以加QQ294618814，一起探讨
*
* @author ding.yi 2017年3月10日 上午10:20:36
*
*/
@SuppressWarnings("serial")
public class GIFCapture extends JFrame {

Toolkit toolkit = Toolkit.getDefaultToolkit();
Dimension screenSize = toolkit.getScreenSize();
JLabel label = new JLabel();
JButton startBtn = new JButton("开始");
JButton existBtn = new JButton("取消");
Boolean isRecording =
4000
false;
Rectangle rectangle = null;
// 临时文件存放的路径
String tempFilePath = "C:/Windows/temp/java_capture/";
// 没帧间隔时间(ms)，100MS就是说1秒钟10张图片
int interval = 100;

public GIFCapture() {

setLayout(null);

label.setName("black");
label.setVisible(false);
label.setBorder(new LineBorder(Color.black, 4));
label.setBackground(new Color(0x00000000, true));
this.add(label);

// 开始和取消按钮
startBtn.setMargin(new Insets(0, 0, 0, 0));
existBtn.setMargin(new Insets(0, 0, 0, 0));
startBtn.setSize(50, 24);
existBtn.setSize(50, 24);
startBtn.setVisible(false);
existBtn.setVisible(false);
existBtn.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
dispose();
System.exit(0);
}
});
startBtn.addActionListener(recordListener);
this.add(startBtn);
this.add(existBtn);

// 窗口属性设置
this.setDefaultCloseOperation(EXIT_ON_CLOSE);
this.setSize(screenSize);
this.setUndecorated(true);
this.setBackground(new Color(0x01000000, true));
this.setVisible(true);
this.setAlwaysOnTop(true);

// 键盘事件，按Esc键可以推出程序
this.addKeyListener(new KeyAdapter() {
@Override
public void keyPressed(KeyEvent e) {
if (e.getKeyCode() == 27) {
dispose();
System.exit(0);
}
}
});
this.addMouseMotionListener(ml);
}

int sx = -1, sy = -1, cx = -1, cy = -1;
boolean isDrag = false;
MouseMotionListener ml = new MouseMotionListener() {
@Override
public void mouseMoved(MouseEvent e) {
if (Math.abs(sx - cx) > 0 && Math.abs(sy - cy) > 0) {
startBtn.setLocation(cx - startBtn.getWidth(), cy);
existBtn.setLocation(cx - startBtn.getWidth() - existBtn.getWidth(), cy);
startBtn.setVisible(true);
existBtn.setVisible(true);
rectangle = new Rectangle(sx + 4, sy + 4, Math.abs(sx - cx) - 8, Math.abs(sy - cy) - 8);

sx = -1;
sy = -1;
cx = -1;
cy = -1;
}
}

@Override
public void mouseDragged(MouseEvent e) {
if (isRecording) {
return;
}
if (sx == -1) {
sx = e.getX();
sy = e.getY();
startBtn.setVisible(false);
label.setSize(0, 0              );
label.setLocation(sx, sy);
} else {
cx = e.getX();
cy = e.getY();
label.setSize(Math.abs(sx - cx), Math.abs(sy - cy));
label.setVisible(true);
}
repaint();
}
};

ActionListener recordListener = new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
isRecording = "开始".contentEquals(startBtn.getText());
if (isRecording) {
setBackground(new Color(0x00000000, true));
startBtn.setText("结束");
existBtn.setVisible(false);
startRecording();
} else {
existBtn.setVisible(false);
startBtn.setVisible(false);
}
}
};

protected void startRecording() {
File f = new File(tempFilePath);
if (!f.exists()) {
f.mkdirs();
}

// 先将临时文件夹中的截图全部删除
for (File img : f.listFiles()) {
img.delete();
}

// 开始录制，闪烁边框
new Thread(new BlinkRunnable()).start();

// 开始录制，先将截屏一张一张保存到临时文件夹下
new Thread(new Runnable() {
@Override
public void run() {
try {
while (isRecording) {
creater(); // 开启线程单独截屏
Thread.sleep(interval);
}
ScreenCapture.saveScreen(rectangle, tempFilePath + System.nanoTime() + ".xy");
saveGIF();
} catch (Exception e) {
e.printStackTrace();
}
}

/**
* Q: 这里为何要单独开启线程截屏？
* A: 只为了保证没帧的间隔时间一样，因为截屏需要一点时间，不开启线程截屏会导致gif动画变快
*/
private void creater() {
new Thread(new Runnable() {
@Override
public void run() {
ScreenCapture.saveScreen(rectangle, tempFilePath + System.nanoTime() + ".xy");
}
}).start();
}

/**
* 开始将截屏图片保存为GIF图片，
*/
private void saveGIF() {
label.setBackground(Color.gray);
label.setBorder(new LineBorder(Color.black, 2));
label.setSize(400, 60);
label.setText("正在保存图片，请稍等...");
label.setFont(new Font("宋体", Font.BOLD, 20));

System.out.println("正在保存GIF图片...");
// GIF图片保存路径默认为桌面，没有提供选择保存路径界面，可以优化
String desktopPath = FileSystemView.getFileSystemView().getHomeDirectory() + "/";
ScreenCapture.createGIF(tempFilePath, desktopPath + "JAVA截图" + System.currentTimeMillis() + ".GIF", interval);
System.out.println("完成");
dispose();
System.exit(0);
}
}).start();
}

/**
* 窗口闪烁效果
*/
class BlinkRunnable implements Runnable {
@Override
public void run() {
while (true) {
try {
// isRecording为false表示没有录制，就一直等待
if (!isRecording) {
Thread.sleep(100);
continue;
}

// 来切换边框的颜色 黑红黑红的闪烁，表示正在录制
Color color = null;

if ("black".equals(label.getName())) {
color = Color.red;
label.setName("red");
} else {
color = Color.black;
label.setName("black");
}
label.setBorder(new LineBorder(color, 4));

Thread.sleep(800);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}

}

public static void main(String[] args) throws Exception {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
new GIFCapture();
}

}

自己封装的截屏工具类：ScreenCapture.java

import java.awt.AWTException;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.MouseInfo;
import java.awt.Point;
import java.awt.Rectangle;
import java.awt.Robot;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import javax.imageio.ImageIO;

import com.test.lib.AnimatedGifEncoder;

/**
* 屏幕截取工具
*
* @author ding.yi 2017年3月10日 上午11:17:45
*
*/
public class ScreenCapture {

static List<BufferedImage> captureBuffList = new ArrayList<BufferedImage>();

/**
* 通过坐标和大小截取屏幕，得到BufferedImage
* @param x 截屏起点坐标x
* @param y 截屏起点坐标y
* @param w 宽度
* @param h 高度
* @return BufferedImage
*/
public static BufferedImage getScreen(int x, int y, int w, int h) {
Rectangle rect = new Rectangle(x, y, w, h);
BufferedImage captureImg = null;
Point p = MouseInfo.getPointerInfo().getLocation();

try {
captureImg = new Robot().createScreenCapture(rect);

// 这里截屏的时候花了一个红圆圈，标识鼠标所在的位置，也可以换成一个鼠标央视的图片
// 是为了制作gif动画用的，如果是单纯的截屏就不需要
Graphics g = captureImg.getGraphics();
g.setColor(Color.red);
g.fillArc(p.x - x, p.y - y, 15, 15, 0, 360);
} catch (AWTException e) {
e.printStackTrace();
}
return captureImg;
}

public static void saveScreen(Rectangle rect, String savePath) {
saveScreen(rect.x, rect.y, rect.width, rect.height, savePath);
}

public static void saveScreen(Rectangle rect) {
BufferedImage captureImg = getScreen(rect.x, rect.y, rect.width, rect.height);
captureBuffList.add(captureImg);
}

public static void createGIF(String gifPath, int interval) {
try {
AnimatedGifEncoder e = new AnimatedGifEncoder();
e.setRepeat(0);
e.start(gifPath);
for (BufferedImage bufferedImage : captureBuffList) {
e.setDelay(interval);下·
e.addFrame(bufferedImage);
}
e.finish();
} catch (Exception e) {
e.printStackTrace();
} finally {
captureBuffList.clear();
}
}

/**
* 保存截屏
* @param x 截屏x坐标
* @param y 截屏y坐标
* @param w 截屏宽度
* @param h 截屏高度
* @param savePath 截屏图片保存位置
*/
public static void saveScreen(int x, int y, int w, int h, String savePath) {
BufferedImage captureImg = getScreen(x, y, w, h);
File saveFile = new File(savePath);

if (!saveFile.getParentFile().exists()) {
saveFile.mkdirs();
}

try {
ImageIO.write(captureImg, "PNG", saveFile);
} catch (IOException e) {
e.printStackTrace();
}
}

/**
* 将文件夹中的所有图片制作成GIF图片，GIF图片制作的方法是从网上找来的（AnimatedGifEncoder、LZWEncoder和NeuQuant三个类）。
* @param folderPath    帧图片所在文件夹
* @param gifPath       保存的GIF图片路径
* @param interval      没帧间隔（毫秒）
*/
public static void createGIF(String folderPath, String gifPath, int interval) {
File[] pic = new File(folderPath).listFiles();
try {
AnimatedGifEncoder e = new AnimatedGifEncoder();
e.setRepeat(0);
e.start(gifPath);
BufferedImage src[] = new BufferedImage[pic.length];
for (int i = 0; i < src.length; i++) {
e.setDelay(interval); // 设置播放的延迟时间
src[i] = ImageIO.read(pic[i]); // 读入需要播放的jpg文件
e.addFrame(src[i]); // 添加到帧中
}
e.finish();
} catch (Exception e) {
e.printStackTrace();
}
}

public static void main(String[] args) throws InterruptedException {
for (int i = 1; i <= 100; i++) {
final int j = i;
new Thread(new Runnable() {
@Override
public void run() {
saveScreen(0, 0, 1069, 746, "F:/a/" + (j < 10 ? "0" : "") + j + ".png");
}
}).start();
Thread.sleep(100);
}
createGIF("F:/a/", "F:/a/gif.gif", 100);
}

}

GIF工具类，一共三个

NeuQuant.java

public 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);
}
}

LZWEncoder.java

import java.io.IOException;
import java.io.OutputStream;

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

AnimatedGifEncoder.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.
*
* <pre>
* Example:
*    AnimatedGifEncoder e = new AnimatedGifEncoder();
*    e.start(outputFileName);
*    e.setDelay(1000);   // 1 frame per sec
*    e.addFrame(image1);
*    e.addFrame(image2);
*    e.finish();
* </pre>
*
* 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.com.
*
* @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 <code>finish()</code> flushes all frames. If
* <code>setSize</code> was not invoked, the size of the first image is used
* for all subsequent frames.
*
* @param im
*            BufferedImage containing frame to write.
* @return true if successful.
*/
public boolean addFrame(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
* <code>setDelay(1000/fps)</code>.
*
* @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));
}
}
}