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package cn.luues.tool.captcha.graphical.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;

/**
 * Gif生成工具
 * 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. */ public class GifEncoder { 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. */ 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; } //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 { out.write(0x3b); // gif trailer 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]; Quant nq = new Quant(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 * * @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; ) { 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 * * @throws IOException IO异常 */ 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 * * @throws IOException IO异常 */ 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 * * @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 out.write(0); // background color index out.write(0); // pixel aspect ratio - assume 1:1 } /** * Writes Netscape application extension to define * repeat count. * * @throws IOException IO异常 */ 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 * * @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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