提交代码
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synchronized
491
src/main/java/com/wf/captcha/GifEncoder.java
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491
src/main/java/com/wf/captcha/GifEncoder.java
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package com.wf.captcha;
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import java.awt.*;
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import java.awt.image.BufferedImage;
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import java.awt.image.DataBufferByte;
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import java.io.BufferedOutputStream;
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import java.io.ByteArrayOutputStream;
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import java.io.FileOutputStream;
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import java.io.IOException;
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import java.io.OutputStream;
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/**
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* Class AnimatedGifEncoder - Encodes a GIF file consisting of one or
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* more frames.
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* <pre>
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* Example:
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* AnimatedGifEncoder e = new AnimatedGifEncoder();
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* e.start(outputFileName);
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* e.setDelay(1000); // 1 frame per sec
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* e.addFrame(image1);
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* e.addFrame(image2);
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* e.finish();
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* </pre>
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* No copyright asserted on the source code of this class. May be used
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* for any purpose, however, refer to the Unisys LZW patent for restrictions
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* on use of the associated Encoder class. Please forward any corrections
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* to questions at fmsware.com.
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*
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* @author wuhongjun
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* @version 1.03 November 2003
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*
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*/
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public class GifEncoder
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{
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protected int width; // image size
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protected int height;
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protected Color transparent = null; // transparent color if given
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protected int transIndex; // transparent index in color table
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protected int repeat = -1; // no repeat
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protected int delay = 0; // frame delay (hundredths)
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protected boolean started = false; // ready to output frames
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protected OutputStream out;
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protected BufferedImage image; // current frame
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protected byte[] pixels; // BGR byte array from frame
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protected byte[] indexedPixels; // converted frame indexed to palette
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protected int colorDepth; // number of bit planes
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protected byte[] colorTab; // RGB palette
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protected boolean[] usedEntry = new boolean[256]; // active palette entries
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protected int palSize = 7; // color table size (bits-1)
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protected int dispose = -1; // disposal code (-1 = use default)
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protected boolean closeStream = false; // close stream when finished
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protected boolean firstFrame = true;
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protected boolean sizeSet = false; // if false, get size from first frame
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protected int sample = 10; // default sample interval for quantizer
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/**
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* Sets the delay time between each frame, or changes it
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* for subsequent frames (applies to last frame added).
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*
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* @param ms int delay time in milliseconds
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*/
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public void setDelay(int ms) {
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delay = Math.round(ms / 10.0f);
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}
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/**
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* Sets the GIF frame disposal code for the last added frame
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* and any subsequent frames. Default is 0 if no transparent
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* color has been set, otherwise 2.
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* @param code int disposal code.
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*/
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public void setDispose(int code) {
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if (code >= 0) {
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dispose = code;
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}
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}
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/**
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* Sets the number of times the set of GIF frames
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* should be played. Default is 1; 0 means play
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* indefinitely. Must be invoked before the first
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* image is added.
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*
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* @param iter int number of iterations.
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* @return
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*/
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public void setRepeat(int iter) {
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if (iter >= 0) {
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repeat = iter;
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}
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}
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/**
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* Sets the transparent color for the last added frame
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* and any subsequent frames.
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* Since all colors are subject to modification
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* in the quantization process, the color in the final
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* palette for each frame closest to the given color
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* becomes the transparent color for that frame.
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* May be set to null to indicate no transparent color.
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*
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* @param c Color to be treated as transparent on display.
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*/
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public void setTransparent(Color c) {
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transparent = c;
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}
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/**
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* Adds next GIF frame. The frame is not written immediately, but is
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* actually deferred until the next frame is received so that timing
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* data can be inserted. Invoking <code>finish()</code> flushes all
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* frames. If <code>setSize</code> was not invoked, the size of the
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* first image is used for all subsequent frames.
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*
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* @param im BufferedImage containing frame to write.
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* @return true if successful.
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*/
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public boolean addFrame(BufferedImage im) {
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if ((im == null) || !started) {
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return false;
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}
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boolean ok = true;
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try {
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if (!sizeSet) {
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// use first frame's size
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setSize(im.getWidth(), im.getHeight());
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}
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image = im;
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getImagePixels(); // convert to correct format if necessary
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analyzePixels(); // build color table & map pixels
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if (firstFrame) {
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writeLSD(); // logical screen descriptior
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writePalette(); // global color table
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if (repeat >= 0) {
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// use NS app extension to indicate reps
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writeNetscapeExt();
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}
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}
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writeGraphicCtrlExt(); // write graphic control extension
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writeImageDesc(); // image descriptor
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if (!firstFrame) {
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writePalette(); // local color table
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}
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writePixels(); // encode and write pixel data
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firstFrame = false;
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} catch (IOException e) {
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ok = false;
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}
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return ok;
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}
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//added by alvaro
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public boolean outFlush() {
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boolean ok = true;
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try {
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out.flush();
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return ok;
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} catch (IOException e) {
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ok = false;
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}
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return ok;
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}
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public byte[] getFrameByteArray() {
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return ((ByteArrayOutputStream) out).toByteArray();
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}
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/**
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* Flushes any pending data and closes output file.
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* If writing to an OutputStream, the stream is not
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* closed.
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*/
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public boolean finish() {
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if (!started) return false;
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boolean ok = true;
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started = false;
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try {
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out.write(0x3b); // gif trailer
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out.flush();
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if (closeStream) {
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out.close();
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}
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} catch (IOException e) {
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ok = false;
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}
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return ok;
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}
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public void reset() {
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// reset for subsequent use
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transIndex = 0;
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out = null;
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image = null;
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pixels = null;
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indexedPixels = null;
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colorTab = null;
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closeStream = false;
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firstFrame = true;
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}
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/**
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* Sets frame rate in frames per second. Equivalent to
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* <code>setDelay(1000/fps)</code>.
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*
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* @param fps float frame rate (frames per second)
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*/
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public void setFrameRate(float fps) {
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if (fps != 0f) {
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delay = Math.round(100f / fps);
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}
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}
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/**
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* Sets quality of color quantization (conversion of images
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* to the maximum 256 colors allowed by the GIF specification).
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* Lower values (minimum = 1) produce better colors, but slow
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* processing significantly. 10 is the default, and produces
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* good color mapping at reasonable speeds. Values greater
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* than 20 do not yield significant improvements in speed.
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*
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* @param quality int greater than 0.
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* @return
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*/
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public void setQuality(int quality) {
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if (quality < 1) quality = 1;
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sample = quality;
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}
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/**
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* Sets the GIF frame size. The default size is the
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* size of the first frame added if this method is
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* not invoked.
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*
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* @param w int frame width.
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* @param h int frame width.
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*/
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public void setSize(int w, int h) {
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if (started && !firstFrame) return;
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width = w;
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height = h;
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if (width < 1) width = 320;
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if (height < 1) height = 240;
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sizeSet = true;
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}
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/**
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* Initiates GIF file creation on the given stream. The stream
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* is not closed automatically.
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*
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* @param os OutputStream on which GIF images are written.
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* @return false if initial write failed.
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*/
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public boolean start(OutputStream os) {
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if (os == null) return false;
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boolean ok = true;
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closeStream = false;
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out = os;
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try {
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writeString("GIF89a"); // header
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} catch (IOException e) {
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ok = false;
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}
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return started = ok;
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}
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/**
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* Initiates writing of a GIF file with the specified name.
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*
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* @param file String containing output file name.
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* @return false if open or initial write failed.
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*/
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public boolean start(String file) {
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boolean ok = true;
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try {
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out = new BufferedOutputStream(new FileOutputStream(file));
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ok = start(out);
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closeStream = true;
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} catch (IOException e) {
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ok = false;
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}
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return started = ok;
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}
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/**
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* Analyzes image colors and creates color map.
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*/
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protected void analyzePixels() {
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int len = pixels.length;
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int nPix = len / 3;
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indexedPixels = new byte[nPix];
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Quant nq = new Quant(pixels, len, sample);
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// initialize quantizer
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colorTab = nq.process(); // create reduced palette
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// convert map from BGR to RGB
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for (int i = 0; i < colorTab.length; i += 3) {
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byte temp = colorTab[i];
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colorTab[i] = colorTab[i + 2];
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colorTab[i + 2] = temp;
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usedEntry[i / 3] = false;
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}
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// map image pixels to new palette
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int k = 0;
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for (int i = 0; i < nPix; i++) {
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int index =
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nq.map(pixels[k++] & 0xff,
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pixels[k++] & 0xff,
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pixels[k++] & 0xff);
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usedEntry[index] = true;
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indexedPixels[i] = (byte) index;
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}
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pixels = null;
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colorDepth = 8;
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palSize = 7;
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// get closest match to transparent color if specified
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if (transparent != null) {
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transIndex = findClosest(transparent);
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}
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}
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/**
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* Returns index of palette color closest to c
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*
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*/
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protected int findClosest(Color c) {
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if (colorTab == null) return -1;
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int r = c.getRed();
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int g = c.getGreen();
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int b = c.getBlue();
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int minpos = 0;
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int dmin = 256 * 256 * 256;
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int len = colorTab.length;
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for (int i = 0; i < len;) {
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int dr = r - (colorTab[i++] & 0xff);
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int dg = g - (colorTab[i++] & 0xff);
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int db = b - (colorTab[i] & 0xff);
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int d = dr * dr + dg * dg + db * db;
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int index = i / 3;
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if (usedEntry[index] && (d < dmin)) {
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dmin = d;
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minpos = index;
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}
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i++;
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}
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return minpos;
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}
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/**
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* Extracts image pixels into byte array "pixels"
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*/
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protected void getImagePixels() {
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int w = image.getWidth();
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int h = image.getHeight();
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int type = image.getType();
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if ((w != width)
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|| (h != height)
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|| (type != BufferedImage.TYPE_3BYTE_BGR)) {
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// create new image with right size/format
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BufferedImage temp =
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new BufferedImage(width, height, BufferedImage.TYPE_3BYTE_BGR);
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Graphics2D g = temp.createGraphics();
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g.drawImage(image, 0, 0, null);
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image = temp;
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}
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pixels = ((DataBufferByte) image.getRaster().getDataBuffer()).getData();
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}
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/**
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* Writes Graphic Control Extension
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*/
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protected void writeGraphicCtrlExt() throws IOException {
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out.write(0x21); // extension introducer
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out.write(0xf9); // GCE label
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out.write(4); // data block size
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int transp, disp;
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if (transparent == null) {
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transp = 0;
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disp = 0; // dispose = no action
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} else {
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transp = 1;
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disp = 2; // force clear if using transparent color
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}
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if (dispose >= 0) {
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disp = dispose & 7; // user override
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}
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disp <<= 2;
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// packed fields
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out.write(0 | // 1:3 reserved
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disp | // 4:6 disposal
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0 | // 7 user input - 0 = none
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transp); // 8 transparency flag
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writeShort(delay); // delay x 1/100 sec
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out.write(transIndex); // transparent color index
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out.write(0); // block terminator
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}
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/**
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* Writes Image Descriptor
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*/
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protected void writeImageDesc() throws IOException {
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out.write(0x2c); // image separator
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writeShort(0); // image position x,y = 0,0
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writeShort(0);
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writeShort(width); // image size
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writeShort(height);
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// packed fields
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if (firstFrame) {
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// no LCT - GCT is used for first (or only) frame
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out.write(0);
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} else {
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// specify normal LCT
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out.write(0x80 | // 1 local color table 1=yes
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0 | // 2 interlace - 0=no
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0 | // 3 sorted - 0=no
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0 | // 4-5 reserved
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palSize); // 6-8 size of color table
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}
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}
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/**
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* Writes Logical Screen Descriptor
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*/
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protected void writeLSD() throws IOException {
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// logical screen size
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writeShort(width);
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writeShort(height);
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// packed fields
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out.write((0x80 | // 1 : global color table flag = 1 (gct used)
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0x70 | // 2-4 : color resolution = 7
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0x00 | // 5 : gct sort flag = 0
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palSize)); // 6-8 : gct size
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out.write(0); // background color index
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out.write(0); // pixel aspect ratio - assume 1:1
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}
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/**
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* Writes Netscape application extension to define
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* repeat count.
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*/
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protected void writeNetscapeExt() throws IOException {
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out.write(0x21); // extension introducer
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out.write(0xff); // app extension label
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out.write(11); // block size
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writeString("NETSCAPE" + "2.0"); // app id + auth code
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out.write(3); // sub-block size
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out.write(1); // loop sub-block id
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writeShort(repeat); // loop count (extra iterations, 0=repeat forever)
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out.write(0); // block terminator
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}
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/**
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* Writes color table
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*/
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protected void writePalette() throws IOException {
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out.write(colorTab, 0, colorTab.length);
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int n = (3 * 256) - colorTab.length;
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for (int i = 0; i < n; i++) {
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out.write(0);
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}
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}
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/**
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* Encodes and writes pixel data
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*/
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protected void writePixels() throws IOException {
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Encoder encoder = new Encoder(width, height, indexedPixels, colorDepth);
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encoder.encode(out);
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}
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/**
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* Write 16-bit value to output stream, LSB first
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*/
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protected void writeShort(int value) throws IOException {
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out.write(value & 0xff);
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out.write((value >> 8) & 0xff);
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}
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/**
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* Writes string to output stream
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*/
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protected void writeString(String s) throws IOException {
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for (int i = 0; i < s.length(); i++) {
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out.write((byte) s.charAt(i));
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}
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}
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}
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