2188 lines
68 KiB
C#
2188 lines
68 KiB
C#
using System;
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using System.Collections;
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using System.Drawing;
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using System.IO;
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namespace TBAppraisalTools
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{
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public class AnimatedGifEncoder
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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 = Color.Empty; // 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 bool started = false; // ready to output frames
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// protected BinaryWriter bw;
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protected FileStream fs;
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protected Image 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 bool[] usedEntry = new bool[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 bool closeStream = false; // close stream when finished
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protected bool firstFrame = true;
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protected bool 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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{
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delay = (int)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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{
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if (code >= 0)
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{
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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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{
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if (iter >= 0)
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{
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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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{
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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 bool AddFrame(Image im)
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{
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if ((im == null) || !started)
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{
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return false;
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}
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bool ok = true;
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try
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{
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if (!sizeSet)
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{
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// use first frame's size
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SetSize(im.Width, im.Height);
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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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{
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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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{
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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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{
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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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}
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catch (IOException e)
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{
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ok = false;
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}
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return ok;
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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 bool Finish()
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{
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if (!started) return false;
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bool ok = true;
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started = false;
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try
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{
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fs.WriteByte(0x3b); // gif trailer
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fs.Flush();
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if (closeStream)
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{
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fs.Close();
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}
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}
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catch (IOException e)
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{
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ok = false;
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}
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// reset for subsequent use
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transIndex = 0;
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fs = 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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return ok;
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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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{
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if (fps != 0f)
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{
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delay = (int)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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{
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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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{
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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 bool Start(FileStream os)
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{
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if (os == null) return false;
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bool ok = true;
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closeStream = false;
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fs = os;
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try
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{
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WriteString("GIF89a"); // header
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}
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catch (IOException e)
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{
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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 bool Start(String file)
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{
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bool ok = true;
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try
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{
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// bw = new BinaryWriter( new FileStream( file, FileMode.OpenOrCreate, FileAccess.Write, FileShare.None ) );
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fs = new FileStream(file, FileMode.OpenOrCreate, FileAccess.Write, FileShare.None);
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ok = Start(fs);
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closeStream = true;
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}
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catch (IOException e)
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{
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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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{
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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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NeuQuant nq = new NeuQuant(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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// {
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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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{
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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 != Color.Empty)
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{
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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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{
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if (colorTab == null) return -1;
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int r = c.R;
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int g = c.G;
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int b = c.B;
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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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{
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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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{
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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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{
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int w = image.Width;
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int h = image.Height;
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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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)
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{
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// create new image with right size/format
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Image temp =
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new Bitmap(width, height);
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Graphics g = Graphics.FromImage(temp);
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g.DrawImage(image, 0, 0);
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image = temp;
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g.Dispose();
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}
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/*
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ToDo:
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improve performance: use unsafe code
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*/
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pixels = new Byte[3 * image.Width * image.Height];
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int count = 0;
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Bitmap tempBitmap = new Bitmap(image);
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for (int th = 0; th < image.Height; th++)
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{
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for (int tw = 0; tw < image.Width; tw++)
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{
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Color color = tempBitmap.GetPixel(tw, th);
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pixels[count] = color.R;
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count++;
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pixels[count] = color.G;
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count++;
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pixels[count] = color.B;
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count++;
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}
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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()
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{
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fs.WriteByte(0x21); // extension introducer
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fs.WriteByte(0xf9); // GCE label
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fs.WriteByte(4); // data block size
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int transp, disp;
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if (transparent == Color.Empty)
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{
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transp = 0;
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disp = 0; // dispose = no action
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}
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else
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{
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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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{
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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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fs.WriteByte(Convert.ToByte(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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fs.WriteByte(Convert.ToByte(transIndex)); // transparent color index
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fs.WriteByte(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()
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{
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fs.WriteByte(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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{
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// no LCT - GCT is used for first (or only) frame
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fs.WriteByte(0);
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}
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else
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{
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// specify normal LCT
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fs.WriteByte(Convert.ToByte(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()
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{
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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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fs.WriteByte(Convert.ToByte(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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fs.WriteByte(0); // background color index
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fs.WriteByte(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()
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{
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fs.WriteByte(0x21); // extension introducer
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fs.WriteByte(0xff); // app extension label
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fs.WriteByte(11); // block size
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WriteString("NETSCAPE" + "2.0"); // app id + auth code
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fs.WriteByte(3); // sub-block size
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fs.WriteByte(1); // loop sub-block id
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WriteShort(repeat); // loop count (extra iterations, 0=repeat forever)
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fs.WriteByte(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()
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{
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fs.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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{
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fs.WriteByte(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()
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{
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LZWEncoder encoder =
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new LZWEncoder(width, height, indexedPixels, colorDepth);
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encoder.Encode(fs);
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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)
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{
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fs.WriteByte(Convert.ToByte(value & 0xff));
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fs.WriteByte(Convert.ToByte((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)
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{
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char[] chars = s.ToCharArray();
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for (int i = 0; i < chars.Length; i++)
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{
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fs.WriteByte((byte)chars[i]);
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}
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}
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}
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public class NeuQuant
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{
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protected static readonly int netsize = 256; /* number of colours used */
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/* four primes near 500 - assume no image has a length so large */
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/* that it is divisible by all four primes */
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protected static readonly int prime1 = 499;
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protected static readonly int prime2 = 491;
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protected static readonly int prime3 = 487;
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protected static readonly int prime4 = 503;
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protected static readonly int minpicturebytes = (3 * prime4);
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/* minimum size for input image */
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/* Program Skeleton
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----------------
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[select samplefac in range 1..30]
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[read image from input file]
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pic = (unsigned char*) malloc(3*width*height);
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initnet(pic,3*width*height,samplefac);
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learn();
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unbiasnet();
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[write output image header, using writecolourmap(f)]
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inxbuild();
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write output image using inxsearch(b,g,r) */
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/* Network Definitions
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------------------- */
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protected static readonly int maxnetpos = (netsize - 1);
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protected static readonly int netbiasshift = 4; /* bias for colour values */
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protected static readonly int ncycles = 100; /* no. of learning cycles */
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/* defs for freq and bias */
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protected static readonly int intbiasshift = 16; /* bias for fractions */
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protected static readonly int intbias = (((int)1) << intbiasshift);
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protected static readonly int gammashift = 10; /* gamma = 1024 */
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protected static readonly int gamma = (((int)1) << gammashift);
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protected static readonly int betashift = 10;
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protected static readonly int beta = (intbias >> betashift); /* beta = 1/1024 */
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protected static readonly int betagamma =
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(intbias << (gammashift - betashift));
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/* defs for decreasing radius factor */
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protected static readonly int initrad = (netsize >> 3); /* for 256 cols, radius starts */
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protected static readonly int radiusbiasshift = 6; /* at 32.0 biased by 6 bits */
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protected static readonly int radiusbias = (((int)1) << radiusbiasshift);
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protected static readonly int initradius = (initrad * radiusbias); /* and decreases by a */
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protected static readonly int radiusdec = 30; /* factor of 1/30 each cycle */
|
|
|
|
/* defs for decreasing alpha factor */
|
|
protected static readonly int alphabiasshift = 10; /* alpha starts at 1.0 */
|
|
protected static readonly int initalpha = (((int)1) << alphabiasshift);
|
|
|
|
protected int alphadec; /* biased by 10 bits */
|
|
|
|
/* radbias and alpharadbias used for radpower calculation */
|
|
protected static readonly int radbiasshift = 8;
|
|
protected static readonly int radbias = (((int)1) << radbiasshift);
|
|
protected static readonly int alpharadbshift = (alphabiasshift + radbiasshift);
|
|
protected static readonly 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: readonly 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);
|
|
}
|
|
}
|
|
|
|
public class LZWEncoder
|
|
{
|
|
|
|
private static readonly 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 readonly int BITS = 12;
|
|
|
|
static readonly 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.
|
|
bool 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];
|
|
|
|
//----------------------------------------------------------------------------
|
|
public 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 Add(byte c, Stream outs)
|
|
{
|
|
accum[a_count++] = c;
|
|
if (a_count >= 254)
|
|
Flush(outs);
|
|
}
|
|
|
|
// Clear out the hash table
|
|
|
|
// table clear for block compress
|
|
void ClearTable(Stream outs)
|
|
{
|
|
ResetCodeTable(hsize);
|
|
free_ent = ClearCode + 2;
|
|
clear_flg = true;
|
|
|
|
Output(ClearCode, outs);
|
|
}
|
|
|
|
// reset code table
|
|
void ResetCodeTable(int hsize)
|
|
{
|
|
for (int i = 0; i < hsize; ++i)
|
|
htab[i] = -1;
|
|
}
|
|
|
|
void Compress(int init_bits, Stream outs)
|
|
{
|
|
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;
|
|
ResetCodeTable(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];
|
|
goto 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
|
|
ClearTable(outs);
|
|
}
|
|
// Put out the final code.
|
|
Output(ent, outs);
|
|
Output(EOFCode, outs);
|
|
}
|
|
|
|
//----------------------------------------------------------------------------
|
|
public void Encode(Stream os)
|
|
{
|
|
os.WriteByte(Convert.ToByte(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.WriteByte(0); // write block terminator
|
|
}
|
|
|
|
// Flush the packet to disk, and reset the accumulator
|
|
void Flush(Stream outs)
|
|
{
|
|
if (a_count > 0)
|
|
{
|
|
outs.WriteByte(Convert.ToByte(a_count));
|
|
outs.Write(accum, 0, a_count);
|
|
a_count = 0;
|
|
}
|
|
}
|
|
|
|
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;
|
|
|
|
int temp = curPixel + 1;
|
|
if (temp < pixAry.GetUpperBound(0))
|
|
{
|
|
byte pix = pixAry[curPixel++];
|
|
|
|
return pix & 0xff;
|
|
}
|
|
return 0xff;
|
|
}
|
|
|
|
void Output(int code, Stream outs)
|
|
{
|
|
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)
|
|
{
|
|
Add((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)
|
|
{
|
|
Add((byte)(cur_accum & 0xff), outs);
|
|
cur_accum >>= 8;
|
|
cur_bits -= 8;
|
|
}
|
|
|
|
Flush(outs);
|
|
}
|
|
}
|
|
}
|
|
|
|
public class GifDecoder
|
|
{
|
|
|
|
/**
|
|
* File read status: No errors.
|
|
*/
|
|
public static readonly int STATUS_OK = 0;
|
|
|
|
/**
|
|
* File read status: Error decoding file (may be partially decoded)
|
|
*/
|
|
public static readonly int STATUS_FORMAT_ERROR = 1;
|
|
|
|
/**
|
|
* File read status: Unable to open source.
|
|
*/
|
|
public static readonly int STATUS_OPEN_ERROR = 2;
|
|
|
|
protected Stream inStream;
|
|
protected int status;
|
|
|
|
protected int width; // full image width
|
|
protected int height; // full image height
|
|
protected bool gctFlag; // global color table used
|
|
protected int gctSize; // size of global color table
|
|
protected int loopCount = 1; // iterations; 0 = repeat forever
|
|
|
|
protected int[] gct; // global color table
|
|
protected int[] lct; // local color table
|
|
protected int[] act; // active color table
|
|
|
|
protected int bgIndex; // background color index
|
|
protected int bgColor; // background color
|
|
protected int lastBgColor; // previous bg color
|
|
protected int pixelAspect; // pixel aspect ratio
|
|
|
|
protected bool lctFlag; // local color table flag
|
|
protected bool interlace; // interlace flag
|
|
protected int lctSize; // local color table size
|
|
|
|
protected int ix, iy, iw, ih; // current image rectangle
|
|
protected Rectangle lastRect; // last image rect
|
|
protected Image image; // current frame
|
|
protected Bitmap bitmap;
|
|
protected Image lastImage; // previous frame
|
|
|
|
protected byte[] block = new byte[256]; // current data block
|
|
protected int blockSize = 0; // block size
|
|
|
|
// last graphic control extension info
|
|
protected int dispose = 0;
|
|
// 0=no action; 1=leave in place; 2=restore to bg; 3=restore to prev
|
|
protected int lastDispose = 0;
|
|
protected bool transparency = false; // use transparent color
|
|
protected int delay = 0; // delay in milliseconds
|
|
protected int transIndex; // transparent color index
|
|
|
|
protected static readonly int MaxStackSize = 4096;
|
|
// max decoder pixel stack size
|
|
|
|
// LZW decoder working arrays
|
|
protected short[] prefix;
|
|
protected byte[] suffix;
|
|
protected byte[] pixelStack;
|
|
protected byte[] pixels;
|
|
|
|
protected ArrayList frames; // frames read from current file
|
|
protected int frameCount;
|
|
|
|
public class GifFrame
|
|
{
|
|
public GifFrame(Image im, int del)
|
|
{
|
|
image = im;
|
|
delay = del;
|
|
}
|
|
public Image image;
|
|
public int delay;
|
|
}
|
|
|
|
/**
|
|
* Gets display duration for specified frame.
|
|
*
|
|
* @param n int index of frame
|
|
* @return delay in milliseconds
|
|
*/
|
|
public int GetDelay(int n)
|
|
{
|
|
//
|
|
delay = -1;
|
|
if ((n >= 0) && (n < frameCount))
|
|
{
|
|
delay = ((GifFrame)frames[n]).delay;
|
|
}
|
|
return delay;
|
|
}
|
|
|
|
/**
|
|
* Gets the number of frames read from file.
|
|
* @return frame count
|
|
*/
|
|
public int GetFrameCount()
|
|
{
|
|
return frameCount;
|
|
}
|
|
|
|
/**
|
|
* Gets the first (or only) image read.
|
|
*
|
|
* @return BufferedImage containing first frame, or null if none.
|
|
*/
|
|
public Image GetImage()
|
|
{
|
|
return GetFrame(0);
|
|
}
|
|
|
|
/**
|
|
* Gets the "Netscape" iteration count, if any.
|
|
* A count of 0 means repeat indefinitiely.
|
|
*
|
|
* @return iteration count if one was specified, else 1.
|
|
*/
|
|
public int GetLoopCount()
|
|
{
|
|
return loopCount;
|
|
}
|
|
|
|
/**
|
|
* Creates new frame image from current data (and previous
|
|
* frames as specified by their disposition codes).
|
|
*/
|
|
int[] GetPixels(Bitmap bitmap)
|
|
{
|
|
int[] pixels = new int[3 * image.Width * image.Height];
|
|
int count = 0;
|
|
for (int th = 0; th < image.Height; th++)
|
|
{
|
|
for (int tw = 0; tw < image.Width; tw++)
|
|
{
|
|
Color color = bitmap.GetPixel(tw, th);
|
|
pixels[count] = color.R;
|
|
count++;
|
|
pixels[count] = color.G;
|
|
count++;
|
|
pixels[count] = color.B;
|
|
count++;
|
|
}
|
|
}
|
|
return pixels;
|
|
}
|
|
|
|
void SetPixels(int[] pixels)
|
|
{
|
|
int count = 0;
|
|
for (int th = 0; th < image.Height; th++)
|
|
{
|
|
for (int tw = 0; tw < image.Width; tw++)
|
|
{
|
|
Color color = Color.FromArgb(pixels[count++]);
|
|
bitmap.SetPixel(tw, th, color);
|
|
}
|
|
}
|
|
}
|
|
|
|
protected void SetPixels()
|
|
{
|
|
// expose destination image's pixels as int array
|
|
// int[] dest =
|
|
// (( int ) image.getRaster().getDataBuffer()).getData();
|
|
int[] dest = GetPixels(bitmap);
|
|
|
|
// fill in starting image contents based on last image's dispose code
|
|
if (lastDispose > 0)
|
|
{
|
|
if (lastDispose == 3)
|
|
{
|
|
// use image before last
|
|
int n = frameCount - 2;
|
|
if (n > 0)
|
|
{
|
|
lastImage = GetFrame(n - 1);
|
|
}
|
|
else
|
|
{
|
|
lastImage = null;
|
|
}
|
|
}
|
|
|
|
if (lastImage != null)
|
|
{
|
|
// int[] prev =
|
|
// ((DataBufferInt) lastImage.getRaster().getDataBuffer()).getData();
|
|
int[] prev = GetPixels(new Bitmap(lastImage));
|
|
Array.Copy(prev, 0, dest, 0, width * height);
|
|
// copy pixels
|
|
|
|
if (lastDispose == 2)
|
|
{
|
|
// fill last image rect area with background color
|
|
Graphics g = Graphics.FromImage(image);
|
|
Color c = Color.Empty;
|
|
if (transparency)
|
|
{
|
|
c = Color.FromArgb(0, 0, 0, 0); // assume background is transparent
|
|
}
|
|
else
|
|
{
|
|
c = Color.FromArgb(lastBgColor);
|
|
// c = new Color(lastBgColor); // use given background color
|
|
}
|
|
Brush brush = new SolidBrush(c);
|
|
g.FillRectangle(brush, lastRect);
|
|
brush.Dispose();
|
|
g.Dispose();
|
|
}
|
|
}
|
|
}
|
|
|
|
// copy each source line to the appropriate place in the destination
|
|
int pass = 1;
|
|
int inc = 8;
|
|
int iline = 0;
|
|
for (int i = 0; i < ih; i++)
|
|
{
|
|
int line = i;
|
|
if (interlace)
|
|
{
|
|
if (iline >= ih)
|
|
{
|
|
pass++;
|
|
switch (pass)
|
|
{
|
|
case 2:
|
|
iline = 4;
|
|
break;
|
|
case 3:
|
|
iline = 2;
|
|
inc = 4;
|
|
break;
|
|
case 4:
|
|
iline = 1;
|
|
inc = 2;
|
|
break;
|
|
}
|
|
}
|
|
line = iline;
|
|
iline += inc;
|
|
}
|
|
line += iy;
|
|
if (line < height)
|
|
{
|
|
int k = line * width;
|
|
int dx = k + ix; // start of line in dest
|
|
int dlim = dx + iw; // end of dest line
|
|
if ((k + width) < dlim)
|
|
{
|
|
dlim = k + width; // past dest edge
|
|
}
|
|
int sx = i * iw; // start of line in source
|
|
while (dx < dlim)
|
|
{
|
|
// map color and insert in destination
|
|
int index = ((int)pixels[sx++]) & 0xff;
|
|
int c = act[index];
|
|
if (c != 0)
|
|
{
|
|
dest[dx] = c;
|
|
}
|
|
dx++;
|
|
}
|
|
}
|
|
}
|
|
SetPixels(dest);
|
|
}
|
|
|
|
/**
|
|
* Gets the image contents of frame n.
|
|
*
|
|
* @return BufferedImage representation of frame, or null if n is invalid.
|
|
*/
|
|
public Image GetFrame(int n)
|
|
{
|
|
Image im = null;
|
|
if ((n >= 0) && (n < frameCount))
|
|
{
|
|
im = ((GifFrame)frames[n]).image;
|
|
}
|
|
return im;
|
|
}
|
|
|
|
/**
|
|
* Gets image size.
|
|
*
|
|
* @return GIF image dimensions
|
|
*/
|
|
public Size GetFrameSize()
|
|
{
|
|
return new Size(width, height);
|
|
}
|
|
|
|
/**
|
|
* Reads GIF image from stream
|
|
*
|
|
* @param BufferedInputStream containing GIF file.
|
|
* @return read status code (0 = no errors)
|
|
*/
|
|
public int Read(Stream inStream)
|
|
{
|
|
Init();
|
|
if (inStream != null)
|
|
{
|
|
this.inStream = inStream;
|
|
ReadHeader();
|
|
if (!Error())
|
|
{
|
|
ReadContents();
|
|
if (frameCount < 0)
|
|
{
|
|
status = STATUS_FORMAT_ERROR;
|
|
}
|
|
}
|
|
inStream.Close();
|
|
}
|
|
else
|
|
{
|
|
status = STATUS_OPEN_ERROR;
|
|
}
|
|
return status;
|
|
}
|
|
|
|
/**
|
|
* Reads GIF file from specified file/URL source
|
|
* (URL assumed if name contains ":/" or "file:")
|
|
*
|
|
* @param name String containing source
|
|
* @return read status code (0 = no errors)
|
|
*/
|
|
public int Read(String name)
|
|
{
|
|
status = STATUS_OK;
|
|
try
|
|
{
|
|
name = name.Trim().ToLower();
|
|
status = Read(new FileInfo(name).OpenRead());
|
|
}
|
|
catch (IOException e)
|
|
{
|
|
status = STATUS_OPEN_ERROR;
|
|
}
|
|
|
|
return status;
|
|
}
|
|
|
|
/**
|
|
* Decodes LZW image data into pixel array.
|
|
* Adapted from John Cristy's ImageMagick.
|
|
*/
|
|
protected void DecodeImageData()
|
|
{
|
|
int NullCode = -1;
|
|
int npix = iw * ih;
|
|
int available,
|
|
clear,
|
|
code_mask,
|
|
code_size,
|
|
end_of_information,
|
|
in_code,
|
|
old_code,
|
|
bits,
|
|
code,
|
|
count,
|
|
i,
|
|
datum,
|
|
data_size,
|
|
first,
|
|
top,
|
|
bi,
|
|
pi;
|
|
|
|
if ((pixels == null) || (pixels.Length < npix))
|
|
{
|
|
pixels = new byte[npix]; // allocate new pixel array
|
|
}
|
|
if (prefix == null) prefix = new short[MaxStackSize];
|
|
if (suffix == null) suffix = new byte[MaxStackSize];
|
|
if (pixelStack == null) pixelStack = new byte[MaxStackSize + 1];
|
|
|
|
// Initialize GIF data stream decoder.
|
|
|
|
data_size = Read();
|
|
clear = 1 << data_size;
|
|
end_of_information = clear + 1;
|
|
available = clear + 2;
|
|
old_code = NullCode;
|
|
code_size = data_size + 1;
|
|
code_mask = (1 << code_size) - 1;
|
|
for (code = 0; code < clear; code++)
|
|
{
|
|
prefix[code] = 0;
|
|
suffix[code] = (byte)code;
|
|
}
|
|
|
|
// Decode GIF pixel stream.
|
|
|
|
datum = bits = count = first = top = pi = bi = 0;
|
|
|
|
for (i = 0; i < npix;)
|
|
{
|
|
if (top == 0)
|
|
{
|
|
if (bits < code_size)
|
|
{
|
|
// Load bytes until there are enough bits for a code.
|
|
if (count == 0)
|
|
{
|
|
// Read a new data block.
|
|
count = ReadBlock();
|
|
if (count <= 0)
|
|
break;
|
|
bi = 0;
|
|
}
|
|
datum += (((int)block[bi]) & 0xff) << bits;
|
|
bits += 8;
|
|
bi++;
|
|
count--;
|
|
continue;
|
|
}
|
|
|
|
// Get the next code.
|
|
|
|
code = datum & code_mask;
|
|
datum >>= code_size;
|
|
bits -= code_size;
|
|
|
|
// Interpret the code
|
|
|
|
if ((code > available) || (code == end_of_information))
|
|
break;
|
|
if (code == clear)
|
|
{
|
|
// Reset decoder.
|
|
code_size = data_size + 1;
|
|
code_mask = (1 << code_size) - 1;
|
|
available = clear + 2;
|
|
old_code = NullCode;
|
|
continue;
|
|
}
|
|
if (old_code == NullCode)
|
|
{
|
|
pixelStack[top++] = suffix[code];
|
|
old_code = code;
|
|
first = code;
|
|
continue;
|
|
}
|
|
in_code = code;
|
|
if (code == available)
|
|
{
|
|
pixelStack[top++] = (byte)first;
|
|
code = old_code;
|
|
}
|
|
while (code > clear)
|
|
{
|
|
pixelStack[top++] = suffix[code];
|
|
code = prefix[code];
|
|
}
|
|
first = ((int)suffix[code]) & 0xff;
|
|
|
|
// Add a new string to the string table,
|
|
|
|
if (available >= MaxStackSize)
|
|
break;
|
|
pixelStack[top++] = (byte)first;
|
|
prefix[available] = (short)old_code;
|
|
suffix[available] = (byte)first;
|
|
available++;
|
|
if (((available & code_mask) == 0)
|
|
&& (available < MaxStackSize))
|
|
{
|
|
code_size++;
|
|
code_mask += available;
|
|
}
|
|
old_code = in_code;
|
|
}
|
|
|
|
// Pop a pixel off the pixel stack.
|
|
|
|
top--;
|
|
pixels[pi++] = pixelStack[top];
|
|
i++;
|
|
}
|
|
|
|
for (i = pi; i < npix; i++)
|
|
{
|
|
pixels[i] = 0; // clear missing pixels
|
|
}
|
|
|
|
}
|
|
|
|
/**
|
|
* Returns true if an error was encountered during reading/decoding
|
|
*/
|
|
protected bool Error()
|
|
{
|
|
return status != STATUS_OK;
|
|
}
|
|
|
|
/**
|
|
* Initializes or re-initializes reader
|
|
*/
|
|
protected void Init()
|
|
{
|
|
status = STATUS_OK;
|
|
frameCount = 0;
|
|
frames = new ArrayList();
|
|
gct = null;
|
|
lct = null;
|
|
}
|
|
|
|
/**
|
|
* Reads a single byte from the input stream.
|
|
*/
|
|
protected int Read()
|
|
{
|
|
int curByte = 0;
|
|
try
|
|
{
|
|
curByte = inStream.ReadByte();
|
|
}
|
|
catch (IOException e)
|
|
{
|
|
status = STATUS_FORMAT_ERROR;
|
|
}
|
|
return curByte;
|
|
}
|
|
|
|
/**
|
|
* Reads next variable length block from input.
|
|
*
|
|
* @return number of bytes stored in "buffer"
|
|
*/
|
|
protected int ReadBlock()
|
|
{
|
|
blockSize = Read();
|
|
int n = 0;
|
|
if (blockSize > 0)
|
|
{
|
|
try
|
|
{
|
|
int count = 0;
|
|
while (n < blockSize)
|
|
{
|
|
count = inStream.Read(block, n, blockSize - n);
|
|
if (count == -1)
|
|
break;
|
|
n += count;
|
|
}
|
|
}
|
|
catch (IOException e)
|
|
{
|
|
}
|
|
|
|
if (n < blockSize)
|
|
{
|
|
status = STATUS_FORMAT_ERROR;
|
|
}
|
|
}
|
|
return n;
|
|
}
|
|
|
|
/**
|
|
* Reads color table as 256 RGB integer values
|
|
*
|
|
* @param ncolors int number of colors to read
|
|
* @return int array containing 256 colors (packed ARGB with full alpha)
|
|
*/
|
|
protected int[] ReadColorTable(int ncolors)
|
|
{
|
|
int nbytes = 3 * ncolors;
|
|
int[] tab = null;
|
|
byte[] c = new byte[nbytes];
|
|
int n = 0;
|
|
try
|
|
{
|
|
n = inStream.Read(c, 0, c.Length);
|
|
}
|
|
catch (IOException e)
|
|
{
|
|
}
|
|
if (n < nbytes)
|
|
{
|
|
status = STATUS_FORMAT_ERROR;
|
|
}
|
|
else
|
|
{
|
|
tab = new int[256]; // max size to avoid bounds checks
|
|
int i = 0;
|
|
int j = 0;
|
|
while (i < ncolors)
|
|
{
|
|
int r = ((int)c[j++]) & 0xff;
|
|
int g = ((int)c[j++]) & 0xff;
|
|
int b = ((int)c[j++]) & 0xff;
|
|
tab[i++] = (int)(0xff000000 | (r << 16) | (g << 8) | b);
|
|
}
|
|
}
|
|
return tab;
|
|
}
|
|
|
|
/**
|
|
* Main file parser. Reads GIF content blocks.
|
|
*/
|
|
protected void ReadContents()
|
|
{
|
|
// read GIF file content blocks
|
|
bool done = false;
|
|
while (!(done || Error()))
|
|
{
|
|
int code = Read();
|
|
switch (code)
|
|
{
|
|
|
|
case 0x2C: // image separator
|
|
ReadImage();
|
|
break;
|
|
|
|
case 0x21: // extension
|
|
code = Read();
|
|
switch (code)
|
|
{
|
|
case 0xf9: // graphics control extension
|
|
ReadGraphicControlExt();
|
|
break;
|
|
|
|
case 0xff: // application extension
|
|
ReadBlock();
|
|
String app = "";
|
|
for (int i = 0; i < 11; i++)
|
|
{
|
|
app += (char)block[i];
|
|
}
|
|
if (app.Equals("NETSCAPE2.0"))
|
|
{
|
|
ReadNetscapeExt();
|
|
}
|
|
else
|
|
Skip(); // don't care
|
|
break;
|
|
|
|
default: // uninteresting extension
|
|
Skip();
|
|
break;
|
|
}
|
|
break;
|
|
|
|
case 0x3b: // terminator
|
|
done = true;
|
|
break;
|
|
|
|
case 0x00: // bad byte, but keep going and see what happens
|
|
break;
|
|
|
|
default:
|
|
status = STATUS_FORMAT_ERROR;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Reads Graphics Control Extension values
|
|
*/
|
|
protected void ReadGraphicControlExt()
|
|
{
|
|
Read(); // block size
|
|
int packed = Read(); // packed fields
|
|
dispose = (packed & 0x1c) >> 2; // disposal method
|
|
if (dispose == 0)
|
|
{
|
|
dispose = 1; // elect to keep old image if discretionary
|
|
}
|
|
transparency = (packed & 1) != 0;
|
|
delay = ReadShort() * 10; // delay in milliseconds
|
|
transIndex = Read(); // transparent color index
|
|
Read(); // block terminator
|
|
}
|
|
|
|
/**
|
|
* Reads GIF file header information.
|
|
*/
|
|
protected void ReadHeader()
|
|
{
|
|
String id = "";
|
|
for (int i = 0; i < 6; i++)
|
|
{
|
|
id += (char)Read();
|
|
}
|
|
if (!id.StartsWith("GIF"))
|
|
{
|
|
status = STATUS_FORMAT_ERROR;
|
|
return;
|
|
}
|
|
|
|
ReadLSD();
|
|
if (gctFlag && !Error())
|
|
{
|
|
gct = ReadColorTable(gctSize);
|
|
bgColor = gct[bgIndex];
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Reads next frame image
|
|
*/
|
|
protected void ReadImage()
|
|
{
|
|
ix = ReadShort(); // (sub)image position & size
|
|
iy = ReadShort();
|
|
iw = ReadShort();
|
|
ih = ReadShort();
|
|
|
|
int packed = Read();
|
|
lctFlag = (packed & 0x80) != 0; // 1 - local color table flag
|
|
interlace = (packed & 0x40) != 0; // 2 - interlace flag
|
|
// 3 - sort flag
|
|
// 4-5 - reserved
|
|
lctSize = 2 << (packed & 7); // 6-8 - local color table size
|
|
|
|
if (lctFlag)
|
|
{
|
|
lct = ReadColorTable(lctSize); // read table
|
|
act = lct; // make local table active
|
|
}
|
|
else
|
|
{
|
|
act = gct; // make global table active
|
|
if (bgIndex == transIndex)
|
|
bgColor = 0;
|
|
}
|
|
int save = 0;
|
|
if (transparency)
|
|
{
|
|
save = act[transIndex];
|
|
act[transIndex] = 0; // set transparent color if specified
|
|
}
|
|
|
|
if (act == null)
|
|
{
|
|
status = STATUS_FORMAT_ERROR; // no color table defined
|
|
}
|
|
|
|
if (Error()) return;
|
|
|
|
DecodeImageData(); // decode pixel data
|
|
Skip();
|
|
|
|
if (Error()) return;
|
|
|
|
frameCount++;
|
|
|
|
// create new image to receive frame data
|
|
// image =
|
|
// new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB_PRE);
|
|
|
|
bitmap = new Bitmap(width, height);
|
|
image = bitmap;
|
|
SetPixels(); // transfer pixel data to image
|
|
|
|
frames.Add(new GifFrame(bitmap, delay)); // add image to frame list
|
|
|
|
if (transparency)
|
|
{
|
|
act[transIndex] = save;
|
|
}
|
|
ResetFrame();
|
|
|
|
}
|
|
|
|
/**
|
|
* Reads Logical Screen Descriptor
|
|
*/
|
|
protected void ReadLSD()
|
|
{
|
|
|
|
// logical screen size
|
|
width = ReadShort();
|
|
height = ReadShort();
|
|
|
|
// packed fields
|
|
int packed = Read();
|
|
gctFlag = (packed & 0x80) != 0; // 1 : global color table flag
|
|
// 2-4 : color resolution
|
|
// 5 : gct sort flag
|
|
gctSize = 2 << (packed & 7); // 6-8 : gct size
|
|
|
|
bgIndex = Read(); // background color index
|
|
pixelAspect = Read(); // pixel aspect ratio
|
|
}
|
|
|
|
/**
|
|
* Reads Netscape extenstion to obtain iteration count
|
|
*/
|
|
protected void ReadNetscapeExt()
|
|
{
|
|
do
|
|
{
|
|
ReadBlock();
|
|
if (block[0] == 1)
|
|
{
|
|
// loop count sub-block
|
|
int b1 = ((int)block[1]) & 0xff;
|
|
int b2 = ((int)block[2]) & 0xff;
|
|
loopCount = (b2 << 8) | b1;
|
|
}
|
|
} while ((blockSize > 0) && !Error());
|
|
}
|
|
|
|
/**
|
|
* Reads next 16-bit value, LSB first
|
|
*/
|
|
protected int ReadShort()
|
|
{
|
|
// read 16-bit value, LSB first
|
|
return Read() | (Read() << 8);
|
|
}
|
|
|
|
/**
|
|
* Resets frame state for reading next image.
|
|
*/
|
|
protected void ResetFrame()
|
|
{
|
|
lastDispose = dispose;
|
|
lastRect = new Rectangle(ix, iy, iw, ih);
|
|
lastImage = image;
|
|
lastBgColor = bgColor;
|
|
// int dispose = 0;
|
|
bool transparency = false;
|
|
int delay = 0;
|
|
lct = null;
|
|
}
|
|
|
|
/**
|
|
* Skips variable length blocks up to and including
|
|
* next zero length block.
|
|
*/
|
|
protected void Skip()
|
|
{
|
|
do
|
|
{
|
|
ReadBlock();
|
|
} while ((blockSize > 0) && !Error());
|
|
}
|
|
}
|
|
}
|