com.github.zh9131101.utils.AnimatedGifEncoder Maven / Gradle / Ivy
package com.github.zh9131101.utils;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.awt.image.DataBufferByte;
import java.io.BufferedOutputStream;
import java.io.ByteArrayOutputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
/**
*
* 包含了大部分GIF图像的功能，比如帧间延时，换帧方式，透明度选择，还可以生成256色调色板
* 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 Encoder class. Please forward any corrections
* to questions at fmsware.com.
*
*
* @author zh9131101
* @version V1.0.0
* @date 2021-01-07 22:03
* @since 1.0
*/
public class AnimatedGifEncoder {
/**
* image size
*/
protected int width;
protected int height;
/**
* transparent color if given
*/
protected Color transparent = null;
/**
* transparent index in color table
*/
protected int transIndex;
/**
* no repeat
*/
protected int repeat = -1;
/**
* frame delay (hundredths)
*/
protected int delay = 0;
/**
* ready to output frames
*/
protected boolean started = false;
protected OutputStream out;
/**
* current frame
*/
protected BufferedImage image;
/**
* BGR byte array from frame
*/
protected byte[] pixels;
/**
* converted frame indexed to palette
*/
protected byte[] indexedPixels;
/**
* number of bit planes
*/
protected int colorDepth;
/**
* RGB palette
*/
protected byte[] colorTab;
/**
* active palette entries
*/
protected boolean[] usedEntry = new boolean[256];
/**
* color table size (bits-1)
*/
protected int palSize = 7;
/**
* disposal code (-1 = use default)
*/
protected int dispose = -1;
/**
* close stream when finished
*/
protected boolean closeStream = false;
protected boolean firstFrame = true;
/**
* if false, get size from first frame
*/
protected boolean sizeSet = false;
/**
* default sample interval for quantizer
*/
protected int sample = 10;
/**
* 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.
*/
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;
// convert to correct format if necessary
getImagePixels();
// build color table & map pixels
analyzePixels();
if (firstFrame) {
// logical screen descriptior
writeLSD();
// global color table
writePalette();
if (repeat >= 0) {
// use NS app extension to indicate reps
writeNetscapeExt();
}
}
// write graphic control extension
writeGraphicCtrlExt();
// image descriptor
writeImageDesc();
if (!firstFrame) {
// local color table
writePalette();
}
// encode and write pixel data
writePixels();
firstFrame = false;
} catch (IOException e) {
ok = false;
}
return ok;
}
//added by alvaro
public boolean outFlush() {
boolean ok = true;
try {
out.flush();
return ok;
} catch (IOException e) {
ok = false;
}
return ok;
}
public byte[] getFrameByteArray() {
return ((ByteArrayOutputStream) out).toByteArray();
}
/**
* Flushes any pending data and closes output file.
* If writing to an OutputStream, the stream is not
* closed.
*
* @return boolean
*/
public boolean finish() {
if (!started) {
return false;
}
boolean ok = true;
started = false;
try {
// gif trailer
out.write(0x3b);
out.flush();
if (closeStream) {
out.close();
}
} catch (IOException e) {
ok = false;
}
return ok;
}
public void reset() {
// reset for subsequent use
transIndex = 0;
out = null;
image = null;
pixels = null;
indexedPixels = null;
colorTab = null;
closeStream = false;
firstFrame = true;
}
/**
* 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.
*/
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
// create reduced palette
colorTab = nq.process();
// 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
*
* @param c color
* @return int
*/
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; i++) {
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;
}
}
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
*
* @throws IOException IO异常
*/
protected void writeGraphicCtrlExt() throws IOException {
// extension introducer
out.write(0x21);
// GCE label
out.write(0xf9);
// data block size
out.write(4);
int transp;
int disp;
if (transparent == null) {
transp = 0;
// dispose = no action
disp = 0;
} else {
transp = 1;
// force sessionClear if using transparent color
disp = 2;
}
if (dispose >= 0) {
// user override
disp = dispose & 7;
}
disp <<= 2;
// packed fields
out.write(0 | // 1:3 reserved
disp | // 4:6 disposal
0 | // 7 user input - 0 = none
transp); // 8 transparency flag
// delay x 1/100 sec
writeShort(delay);
// transparent color index
out.write(transIndex);
// block terminator
out.write(0);
}
/**
* Writes Image Descriptor
*
* @throws IOException IO异常
*/
protected void writeImageDesc() throws IOException {
// image separator
out.write(0x2c);
// image position x,y = 0,0
writeShort(0);
writeShort(0);
// image size
writeShort(width);
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
*
* @throws IOException IO异常
*/
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
// background color index
out.write(0);
// pixel aspect ratio - assume 1:1
out.write(0);
}
/**
* Writes Netscape application extension to define
* repeat count.
*
* @throws IOException IO异常
*/
protected void writeNetscapeExt() throws IOException {
// extension introducer
out.write(0x21);
// app extension label
out.write(0xff);
// block size
out.write(11);
// app id + auth code
writeString("NETSCAPE" + "2.0");
// sub-block size
out.write(3);
// loop sub-block id
out.write(1);
// loop count (extra iterations, 0=repeat forever)
writeShort(repeat);
// block terminator
out.write(0);
}
/**
* Writes color table
*
* @throws IOException IO异常
*/
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
*
* @throws IOException IO异常
*/
protected void writePixels() throws IOException {
Encoder encoder = new Encoder(width, height, indexedPixels, colorDepth);
encoder.encode(out);
}
/**
* Write 16-bit value to output stream, LSB first
*
* @param value int
* @throws IOException IO异常
*/
protected void writeShort(int value) throws IOException {
out.write(value & 0xff);
out.write((value >> 8) & 0xff);
}
/**
* Writes string to output stream
*
* @param s string
* @throws IOException IO异常
*/
protected void writeString(String s) throws IOException {
for (int i = 0; i < s.length(); i++) {
out.write((byte) s.charAt(i));
}
}
}
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