方法一：使用AnimatedGif库
Nuget安装包：
1 | Install-Package AnimatedGif -Version 1.0.5 |
https://www.nuget.org/packages/AnimatedGif/
其源码在：https://github.com/mrousavy/AnimatedGif
代码：
1 2 3 4 5 6 | // 33ms delay (~30fps)using (var gif = AnimatedGif.Create("gif.gif", 33)){ var img = Image.FromFile("img.png"); gif.AddFrame(img, delay: -1, quality: GifQuality.Bit8);} |
方法二：使用微软GifBitmapEncoder
https://docs.microsoft.com/en-us/dotnet/api/system.windows.media.imaging.gifbitmapencoder
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 | GifBitmapEncoder gEnc = new GifBitmapEncoder(); while (!bStop) { var img = CopyScreen(); //System.Drawing.Image.FromFile("img.png"); System.Drawing.Bitmap bmpImage = (Bitmap)img; var bmp = bmpImage.GetHbitmap(); var src = System.Windows.Interop.Imaging.CreateBitmapSourceFromHBitmap( bmp, IntPtr.Zero, Int32Rect.Empty, BitmapSizeOptions.FromEmptyOptions()); gEnc.Frames.Add(BitmapFrame.Create(src)); Thread.Sleep(200); } using (FileStream fs = new FileStream("g:\\GifBitmapEncoder.gif", FileMode.Create)) { gEnc.Save(fs); } |
方法三：使用Ngif
源码地址：https://www.codeproject.com/Articles/11505/NGif-Animated-GIF-Encoder-for-NET
代码：
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 | /* create Gif *///you should replace filepathString [] imageFilePaths = new String[]{"c:\\01.png","c:\\02.png","c:\\03.png"}; String outputFilePath = "c:\\test.gif";AnimatedGifEncoder e = new AnimatedGifEncoder();e.Start( outputFilePath );e.SetDelay(500);//-1:no repeat,0:always repeate.SetRepeat(0);for (int i = 0, count = imageFilePaths.Length; i < count; i++ ) { e.AddFrame( Image.FromFile( imageFilePaths[i] ) );}e.Finish();/* extract Gif */string outputPath = "c:\\";GifDecoder gifDecoder = new GifDecoder();gifDecoder.Read( "c:\\test.gif" );for ( int i = 0, count = gifDecoder.GetFrameCount(); i < count; i++ ) { Image frame = gifDecoder.GetFrame( i ); // frame i frame.Save( outputPath + Guid.NewGuid().ToString() + ".png", ImageFormat.Png );} |
注意，此方法生成时间比较长，必须先收集完图片然后一起生成，不能边收集图片边生成，否则gif速度会飞快，那是因为单帧加入时间太长，收集图片掉帧严重。
比如录制屏幕到gif的过程：
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 | //核心方法：注意收集和生成分离 private void UseNgif() { bool bEnd = false; Task.Run(()=> { DateTime dtend = DateTime.Now.AddSeconds(5); while (!bStop && DateTime.Now < dtend) { var img = CopyScreenToImg(false); //System.Drawing.Image.FromFile("img.png"); imgcach.Enqueue(img); Thread.Sleep(100); } bEnd = true; showMsginline("收集图片完成，图片数为：" + imgcach.Count); }); Task.Run(() => { AnimatedGifEncoder ngif = new AnimatedGifEncoder(); ngif.Start("g:\\Ngif.gif"); //ngif.SetFrameRate(24); ngif.SetDelay(100); ngif.SetQuality(15); //-1:no repeat,0:always repeat ngif.SetRepeat(0); while(!bEnd|| imgcach.Count>0) { showMsginline("当前有图片数"+ imgcach.Count); var img2 = GetItemFromQueue(imgcach); if (img2 != null) { ngif.AddFrame(img2); Thread.Sleep(2); } } ngif.Finish(); showMsg("Ngif生成完成！"); }); } |
其他相关方法：
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 | /// <summary> /// 获取屏幕图片 /// </summary> /// <param name="compress">是否压缩</param> /// <returns></returns> private System.Drawing.Image CopyScreenToImg(bool compress=true) { System.Drawing.Image img = new Bitmap(w, h); Graphics g = Graphics.FromImage(img); g.CopyFromScreen(new System.Drawing.Point(x, y), new System.Drawing.Point(0, 0), new System.Drawing.Size(w, h)); if (compress) { System.Drawing.Image img2 = Bitmap.FromStream(CompressionImage(img, quality)); return img2; } else return img; }/// <summary> /// 压缩图片的算法 /// </summary> /// <param name="fileStream">图片流</param> /// <param name="quality">压缩质量，取值在0-100之间，数值越大质量越高</param> /// <returns></returns>private MemoryStream CompressionImage(System.Drawing.Image img, long quality) { using (Bitmap bitmap = new Bitmap(img)) { ImageCodecInfo CodecInfo = GetEncoderInfo("image/jpeg"); System.Drawing.Imaging.Encoder myEncoder = System.Drawing.Imaging.Encoder.Quality; EncoderParameters myEncoderParameters = new EncoderParameters(1); EncoderParameter myEncoderParameter = new EncoderParameter(myEncoder, quality); myEncoderParameters.Param[0] = myEncoderParameter; MemoryStream ms = new MemoryStream(); bitmap.Save(ms, CodecInfo, myEncoderParameters); myEncoderParameters.Dispose(); myEncoderParameter.Dispose(); return ms; } }/// <summary> /// 获取图片编码信息 /// </summary> private ImageCodecInfo GetEncoderInfo(String mimeType) { int j; ImageCodecInfo[] encoders; encoders = ImageCodecInfo.GetImageEncoders(); for (j = 0; j < encoders.Length; ++j) { if (encoders[j].MimeType == mimeType) return encoders[j]; } return null; } ConcurrentQueue<System.Drawing.Image> imgcach = new ConcurrentQueue<System.Drawing.Image>(); //取队列对象 private T GetItemFromQueue<T>(ConcurrentQueue<T> q) { T t = default(T); if (q.TryDequeue(out t)) { return t; } else return default(T); } |
如果嫌Ngif单独组件太麻烦，可以直接用下面一个类Gif.cs：
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2222 2223 2224 2225 2226 2227 2228 2229 2230 2231 2232 2233 | using System;using System.Collections;using System.Drawing;using System.Drawing.Imaging;using System.IO;using System.Runtime.InteropServices;/* Usage to create an animated gif: * var age = new AnimatedGifEncoder(); * age.Start(outputFile); * age.SetDelay(ms); * age.SetRepeat(repeat); // -1: no repeat, 0: always repeat, n: repeat n times * age.AddFrame(frame_n); * age.Finish(); */* Usage to decode an animated gif: * var gd = new GifDecoder(); * gd.Read(gifPath); * for: gd.GetFrameCount(); -> gif.GetFrame(n); */// TODO I'm not sure if this is able to create TRANSPARENT ANIMATED GIFS, if it's not,// GetPixels(...) should be done the same way SetPixels(...) is done// Made 19th of month 9 of 2015.// ============================ LZWEncoder ==============================// = Adapted from Jef Poskanzer's Java port by way of J. M. G. Elliott. =// = K Weiner 12/00 =// ======================================================================// GIFCOMPR.C - GIF Image compression routines//// Lempel-Ziv compression based on 'compress'. GIF modifications by// David Rowley (mgardi@watdcsu.waterloo.edu)// 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)// ==================== NeuQuant Neural-Net Quantization Algorithm =======================// = Copyright (c) 1994 Anthony Dekker =// = NEUQUANT Neural-Net quantization algorithm by Anthony Dekker, 1994. =// = See "Kohonen neural networks for optimal colour quantization" =// = in "Network: Computation in Neural Systems" Vol. 5 (1994) pp 351-367. =// = for a discussion of the algorithm. =// = =// = Any party obtaining a copy of these files from the author, directly or =// = indirectly, is granted, free of charge, a full and unrestricted irrevocable, =// = world-wide, paid up, royalty-free, nonexclusive right and license to deal =// = in this software and documentation files (the "Software"), including without =// = limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, =// = and/or sell copies of the Software, and to permit persons who receive =// = copies from any such party to do so, with the only requirement being =// = that this copyright notice remain intact. =// =======================================================================================public class AnimatedGifEncoder{ protected int width; // image size protected int height; protected Color transparent = Color.Empty; // transparent color if given protected int transIndex; // transparent index in color table protected int repeat = -1; // no repeat protected int delay = 0; // frame delay (hundredths) protected bool started = false; // ready to output frames // protected BinaryWriter bw; protected FileStream fs; protected Image image; // current frame protected byte[] pixels; // BGR byte array from frame protected byte[] indexedPixels; // converted frame indexed to palette protected int colorDepth; // number of bit planes protected byte[] colorTab; // RGB palette protected bool[] usedEntry = new bool[256]; // active palette entries protected int palSize = 7; // color table size (bits-1) protected int dispose = -1; // disposal code (-1 = use default) protected bool closeStream = false; // close stream when finished protected bool firstFrame = true; protected bool sizeSet = false; // if false, get size from first frame protected int sample = 10; // default sample interval for quantizer /// <summary> /// Sets the delay time between each frame, or changes it /// for subsequent frames (applies to last frame added) /// </summary> /// <param name="ms">int delay time in milliseconds</param> public void SetDelay(int ms) { delay = (int)Math.Round(ms / 10.0f); } /// <summary> /// Sets the GIF frame disposal code for the last added frame /// and any subsequent frames. Default is 0 if no transparent /// color has been set, otherwise 2 /// </summary> /// <param name="code">int disposal code</param> public void SetDispose(int code) { if (code >= 0) dispose = code; } /// <summary> /// Sets the number of times the set of GIF frames /// should be played. Default is 1; 0 means play /// indefinitely. Must be invoked before the first /// image is added /// </summary> /// <param name="iter">int number of iterations</param> public void SetRepeat(int iter) { if (iter >= 0) repeat = iter; } /// <summary> /// Sets the transparent color for the last added frame /// and any subsequent frames. /// Since all colors are subject to modification /// in the quantization process, the color in the final /// palette for each frame closest to the given color /// becomes the transparent color for that frame. /// May be set to null to indicate no transparent color /// </summary> /// <param name="c">Color to be treated as transparent on display</param> public void SetTransparent(Color c) { transparent = c; } /// <summary> /// Adds next GIF frame. The frame is not written immediately, but is /// actually deferred until the next frame is received so that timing /// data can be inserted. Invoking <code>finish()</code> flushes all /// frames. If <code>setSize</code> was not invoked, the size of the /// first image is used for all subsequent frames /// </summary> /// <param name="im">BufferedImage containing frame to write</param> /// <returns>true if successful</returns> public bool AddFrame(Image im) { if ((im == null) || !started) return false; bool ok = true; try { if (!sizeSet) // use first frame's size SetSize(im.Width, im.Height); image = im; GetImagePixels(); // convert to correct format if necessary AnalyzePixels(); // build color table & map pixels if (firstFrame) { WriteLSD(); // logical screen descriptior WritePalette(); // global color table if (repeat >= 0) // use NS app extension to indicate reps WriteNetscapeExt(); } WriteGraphicCtrlExt(); // write graphic control extension WriteImageDesc(); // image descriptor if (!firstFrame) // local color table WritePalette(); WritePixels(); // encode and write pixel data firstFrame = false; } catch (IOException) { ok = false; } return ok; } /// Flushes any pending data and closes output file. /// If writing to an OutputStream, the stream is not closed /// </summary> /// <returns>true if successful</returns> public bool Finish() { if (!started) return false; bool ok = true; started = false; try { fs.WriteByte(0x3b); // gif trailer fs.Flush(); if (closeStream) fs.Close(); } catch (IOException) { ok = false; } // reset for subsequent use transIndex = 0; fs = null; image.Dispose(); image = null; pixels = null; indexedPixels = null; colorTab = null; closeStream = false; firstFrame = true; return ok; } /// <summary> /// Sets frame rate in frames per second. Equivalent to /// <code>setDelay(1000/fps)</code> /// </summary> /// <param name="fps">@param fps float frame rate (frames per second)</param> public void SetFrameRate(float fps) { if (fps != 0f) delay = (int)Math.Round(100f / fps); } /// <summary> /// Sets quality of color quantization (conversion of images /// to the maximum 256 colors allowed by the GIF specification). /// Lower values (minimum = 1) produce better colors, but slow /// processing significantly. 10 is the default, and produces /// good color mapping at reasonable speeds. Values greater /// than 20 do not yield significant improvements in speed /// </summary> /// <param name="quality">int greater than 0</param> public void SetQuality(int quality) { if (quality < 1) quality = 1; sample = quality; } /// <summary> /// Sets the GIF frame size. The default size is the /// size of the first frame added if this method is /// not invoked /// </summary> /// <param name="w">int frame width</param> /// <param name="h">int frame height</param> public void SetSize(int w, int h) { if (started && !firstFrame) return; width = w; height = h; if (width < 1) width = 320; if (height < 1) height = 240; sizeSet = true; } /// <summary> /// Initiates GIF file creation on the given stream. The stream /// is not closed automatically. /// </summary> /// <param name="os">OutputStream on which GIF images are written</param> /// <returns>false if initial write failed</returns> public bool Start(FileStream os) { if (os == null) return false; bool ok = true; closeStream = false; fs = os; try { WriteString("GIF89a"); // header } catch (IOException) { ok = false; } return started = ok; } /// <summary> /// Initiates writing of a GIF file with the specified name. /// </summary> /// <param name="file">String containing output file name</param> /// <returns>false if open or initial write failed</returns> public bool Start(string file) { bool ok = true; try { // bw = new BinaryWriter( new FileStream( file, FileMode.OpenOrCreate, FileAccess.Write, FileShare.None ) ); fs = new FileStream(file, FileMode.OpenOrCreate, FileAccess.Write, FileShare.None); ok = Start(fs); closeStream = true; } catch (IOException) { ok = false; } return started = ok; } /// <summary> /// Analyzes image colors and creates color map. /// </summary> protected void AnalyzePixels() { int len = pixels.Length; int nPix = len / 3; indexedPixels = new byte[nPix]; NeuQuant nq = new NeuQuant(pixels, len, sample); // initialize quantizer colorTab = nq.Process(); // create reduced palette // convert map from BGR to RGB // for (int i = 0; i < colorTab.Length; i += 3) // { // byte temp = colorTab[i]; // colorTab[i] = colorTab[i + 2]; // colorTab[i + 2] = temp; // usedEntry[i / 3] = false; // } // map image pixels to new palette int k = 0; for (int i = 0; i < nPix; i++) { int index = nq.Map(pixels[k++] & 0xff, pixels[k++] & 0xff, pixels[k++] & 0xff); usedEntry[index] = true; indexedPixels[i] = (byte)index; } pixels = null; colorDepth = 8; palSize = 7; // get closest match to transparent color if specified if (transparent != Color.Empty) { transIndex = FindClosest(transparent); } } /// <summary> /// Returns index of palette color closest to c /// </summary> /// <param name="c">The original colour</param> /// <returns>The most similar colour index</returns> protected int FindClosest(Color c) { if (colorTab == null) return -1; int r = c.R; int g = c.G; int b = c.B; int minpos = 0; int dmin = 256 * 256 * 256; int len = colorTab.Length; for (int i = 0; i < len;) { int dr = r - (colorTab[i++] & 0xff); int dg = g - (colorTab[i++] & 0xff); int db = b - (colorTab[i] & 0xff); int d = dr * dr + dg * dg + db * db; int index = i / 3; if (usedEntry[index] && (d < dmin)) { dmin = d; minpos = index; } i++; } return minpos; } /// <summary> /// Extracts image pixels into byte array "pixels" /// </summary> protected void GetImagePixels() { int w = image.Width; int h = image.Height; // int type = image.GetType().; if ((w != width) || (h != height) ) { // create new image with right size/format Image temp = new Bitmap(width, height); Graphics g = Graphics.FromImage(temp); g.DrawImage(image, 0, 0); image = temp; g.Dispose(); } pixels = new Byte[3 * image.Width * image.Height]; int count = 0; using (var bmp = new Bitmap(image)) // Temp Bitmap { // Lock the image BitmapData data = bmp.LockBits(new Rectangle(0, 0, bmp.Width, bmp.Height), ImageLockMode.ReadOnly, bmp.PixelFormat); // Create a variable to store the locked bytes of the bitmap byte[] bytes = new byte[Math.Abs(data.Stride) * bmp.Height]; // Get a pointer to the start of our bitmap in the memory IntPtr scan = data.Scan0; // Copy the bytes from the memory to our byte array Marshal.Copy(scan, bytes, 0, bytes.Length); // Calculate how many bytes there are per pixel and others variables to reduce calculations int bytesPerPixel = Image.GetPixelFormatSize(bmp.PixelFormat) / 8; int widthInBytes = data.Width * bytesPerPixel; // The total image width in bytes int yyMax = bmp.Height; // The maximum Y coordinate given by the area rectangle int xxMax = bmp.Width * bytesPerPixel; // The maximum X coordinate given by the area rectangle // Loop through the bitmap rows for (int yy = 0; yy < yyMax; yy++) { // Loop through the bitmap pixels in the row for (int xx = 0; xx < xxMax; xx += bytesPerPixel) { // CurrentIndex Get the row Get the column int ci = yy * data.Stride + xx; pixels[count++] = bytes[ci + 2]; // Red pixels[count++] = bytes[ci + 1]; // Green pixels[count++] = bytes[ci ]; // Blue } } // Unlock the bits of the image bmp.UnlockBits(data); } } /// <summary> /// Writes Graphic Control Extension /// </summary> protected void WriteGraphicCtrlExt() { fs.WriteByte(0x21); // extension introducer fs.WriteByte(0xf9); // GCE label fs.WriteByte(4); // data block size int transp, disp; if (transparent == Color.Empty) { transp = 0; disp = 0; // dispose = no action } else { transp = 1; disp = 2; // force clear if using transparent color } if (dispose >= 0) { disp = dispose & 7; // user override } disp <<= 2; // packed fields fs.WriteByte(Convert.ToByte(0 | // 1:3 reserved disp | // 4:6 disposal 0 | // 7 user input - 0 = none transp)); // 8 transparency flag WriteShort(delay); // delay x 1/100 sec fs.WriteByte(Convert.ToByte(transIndex)); // transparent color index fs.WriteByte(0); // block terminator } /// <summary> /// Writes Image Descriptor /// </summary> protected void WriteImageDesc() { fs.WriteByte(0x2c); // image separator WriteShort(0); // image position x,y = 0,0 WriteShort(0); WriteShort(width); // image size WriteShort(height); // packed fields if (firstFrame) { // no LCT - GCT is used for first (or only) frame fs.WriteByte(0); } else { // specify normal LCT fs.WriteByte(Convert.ToByte(0x80 | // 1 local color table 1=yes 0 | // 2 interlace - 0=no 0 | // 3 sorted - 0=no 0 | // 4-5 reserved palSize)); // 6-8 size of color table } } /// <summary> /// Writes Logical Screen Descriptor /// </summary> protected void WriteLSD() { // logical screen size WriteShort(width); WriteShort(height); // packed fields fs.WriteByte(Convert.ToByte(0x80 | // 1 : global color table flag = 1 (gct used) 0x70 | // 2-4 : color resolution = 7 0x00 | // 5 : gct sort flag = 0 palSize)); // 6-8 : gct size fs.WriteByte(0); // background color index fs.WriteByte(0); // pixel aspect ratio - assume 1:1 } /// <summary> /// Writes Netscape application extension to define /// repeat count /// </summary> protected void WriteNetscapeExt() { fs.WriteByte(0x21); // extension introducer fs.WriteByte(0xff); // app extension label fs.WriteByte(11); // block size WriteString("NETSCAPE" + "2.0"); // app id + auth code fs.WriteByte(3); // sub-block size fs.WriteByte(1); // loop sub-block id WriteShort(repeat); // loop count (extra iterations, 0=repeat forever) fs.WriteByte(0); // block terminator } /// <summary> /// Writes color table /// </summary> protected void WritePalette() { fs.Write(colorTab, 0, colorTab.Length); int n = (3 * 256) - colorTab.Length; for (int i = 0; i < n; i++) { fs.WriteByte(0); } } /// <summary> /// Encodes and writes pixel data /// </summary> protected void WritePixels() { LZWEncoder encoder = new LZWEncoder(width, height, indexedPixels, colorDepth); encoder.Encode(fs); } /// <summary> /// Write 16-bit value to output stream, LSB first /// </summary> /// <param name="value">The short to write</param> protected void WriteShort(int value) { fs.WriteByte(Convert.ToByte(value & 0xff)); fs.WriteByte(Convert.ToByte((value >> 8) & 0xff)); } /// <summary> /// Writes string to output stream /// </summary> /// <param name="s">The string to write</param> protected void WriteString(String s) { char[] chars = s.ToCharArray(); for (int i = 0; i < chars.Length; i++) { fs.WriteByte((byte)chars[i]); } }}public class GifDecoder : IDisposable{ // 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; } /// <summary> /// Gets display duration for specified frame /// </summary> /// <param name="n">int index of frame</param> /// <returns>delay in milliseconds</returns> public int GetDelay(int n) { // delay = -1; if ((n >= 0) && (n < frameCount)) { delay = ((GifFrame)frames[n]).delay; } return delay; } /// <summary> /// Gets the number of frames read from file /// </summary> /// <returns>frame count</returns> public int GetFrameCount() { return frameCount; } /// <summary> /// Gets the first (or only) image read /// </summary> /// <returns>BufferedImage containing first frame, or null if none</returns> public Image GetImage() { return GetFrame(0); } /// <summary> /// Gets the "Netscape" iteration count, if any. /// A count of 0 means repeat indefinitiely. /// </summary> /// <returns>Iteration count if one was specified, else 1</returns> public int GetLoopCount() { return loopCount; } /// <summary> /// Creates new frame image from current data (and previous /// frames as specified by their disposition codes) /// </summary> /// <param name="bitmap">Current bitmap data</param> /// <returns>Pixels array</returns> int[] GetPixels(Bitmap bitmap) { int[] pixels = new int[3 * image.Width * image.Height]; int count = 0; // Lock the image BitmapData data = bitmap.LockBits(new Rectangle(0, 0, bitmap.Width, bitmap.Height), ImageLockMode.ReadOnly, bitmap.PixelFormat); // Create a variable to store the locked bytes of the bitmap byte[] bytes = new byte[Math.Abs(data.Stride) * bitmap.Height]; // Get a pointer to the start of our bitmap in the memory IntPtr scan = data.Scan0; // Copy the bytes from the memory to our byte array Marshal.Copy(scan, bytes, 0, bytes.Length); // Calculate how many bytes there are per pixel and others variables to reduce calculations int bytesPerPixel = Image.GetPixelFormatSize(bitmap.PixelFormat) / 8; int widthInBytes = data.Width * bytesPerPixel; // The total image width in bytes int yyMax = bitmap.Height; // The maximum Y coordinate given by the area rectangle int xxMax = bitmap.Width * bytesPerPixel; // The maximum X coordinate given by the area rectangle // Loop through the bitmap rows for (int yy = 0; yy < yyMax; yy++) { // Loop through the bitmap pixels in the row for (int xx = 0; xx < xxMax; xx += bytesPerPixel) { // CurrentIndex Get the row Get the column int ci = yy * data.Stride + xx; pixels[count++] = bytes[ci + 2]; // Red pixels[count++] = bytes[ci + 1]; // Green pixels[count++] = bytes[ci]; // Blue } } // Unlock the bits of the image bitmap.UnlockBits(data); return pixels; } void SetPixels(int[] pixels) { int count = 0; // Lock the image BitmapData data = bitmap.LockBits(new Rectangle(0, 0, bitmap.Width, bitmap.Height), ImageLockMode.ReadOnly, bitmap.PixelFormat); // Create a variable to store the locked bytes of the bitmap byte[] bytes = new byte[Math.Abs(data.Stride) * bitmap.Height]; // Get a pointer to the start of our bitmap in the memory IntPtr scan = data.Scan0; // Copy the bytes from the memory to our byte array Marshal.Copy(scan, bytes, 0, bytes.Length); // Calculate how many bytes there are per pixel and others variables to reduce calculations int bytesPerPixel = Image.GetPixelFormatSize(bitmap.PixelFormat) / 8; int widthInBytes = data.Width * bytesPerPixel; // The total image width in bytes int yyMax = bitmap.Height; // The maximum Y coordinate given by the area rectangle int xxMax = bitmap.Width * bytesPerPixel; // The maximum X coordinate given by the area rectangle // Loop through the bitmap rows for (int yy = 0; yy < yyMax; yy++) { // Loop through the bitmap pixels in the row for (int xx = 0; xx < xxMax; xx += bytesPerPixel) { Color color = Color.FromArgb(pixels[count++]); // CurrentIndex Get the row Get the column int ci = yy * data.Stride + xx; bytes[ci + 3] = color.A; // Alpha? bytes[ci + 2] = color.R; // Red bytes[ci + 1] = color.G; // Green bytes[ci ] = color.B; // Blue } } // Copy back from our destination bytes array to the dst bitmap in the memory Marshal.Copy(bytes, 0, scan, bytes.Length); // Unlock the bits of the image bitmap.UnlockBits(data); } protected void SetPixels() { // expose destination image's pixels as int array 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); // 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); } /// <summary> /// Gets the image contents of frame n /// </summary> /// <param name="n">The n'th frame</param> /// <returns>BufferedImage representation of frame, or null if n is invalid</returns> public Image GetFrame(int n) { Image im = null; if ((n >= 0) && (n < frameCount)) im = ((GifFrame)frames[n]).image; return im; } /// <summary> /// Gets image size /// </summary> /// <returns>GIF image dimensions</returns> public Size GetFrameSize() { return new Size(width, height); } /// <summary> /// Reads GIF image from stream /// </summary> /// <param name="inStream">BufferedInputStream containing GIF file</param> /// <returns>read status code (0 = no errors)</returns> 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; } /// <summary> /// Reads GIF file from specified file/URL source /// (URL assumed if name contains ":/" or "file:") /// </summary> /// <param name="name">String containing source</param> /// <returns>read status code (0 = no errors)</returns> public int Read(String name) { status = STATUS_OK; try { name = name.Trim().ToLower(); status = Read(new FileInfo(name).OpenRead()); } catch (IOException) { status = STATUS_OPEN_ERROR; } return status; } /// <summary> /// Decodes LZW image data into pixel array. /// Adapted from John Cristy's ImageMagick /// </summary> 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 } } /// <summary> /// Returns true if an error was encountered during reading/decoding /// </summary> /// <returns>true if an error occured</returns> protected bool Error() { return status != STATUS_OK; } /// <summary> /// Initializes or re-initializes reader /// </summary> protected void Init() { status = STATUS_OK; frameCount = 0; frames = new ArrayList(); gct = null; lct = null; } /// <summary> /// Reads a single byte from the input stream. /// </summary> /// <returns>The byte read</returns> protected int Read() { int curByte = 0; try { curByte = inStream.ReadByte(); } catch (IOException) { status = STATUS_FORMAT_ERROR; } return curByte; } /// <summary> /// Reads next variable length block from input. /// </summary> /// <returns>number of bytes stored in "buffer"</returns> 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) { } if (n < blockSize) { status = STATUS_FORMAT_ERROR; } } return n; } /// <summary> /// Reads color table as 256 RGB integer values /// </summary> /// <param name="ncolors">int number of colors to read</param> /// <returns>int array containing 256 colors (packed ARGB with full alpha)</returns> 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) { } 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; } /// <summary> /// Main file parser. Reads GIF content blocks /// </summary> 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; } } } /// <summary> /// Reads Graphics Control Extension values /// </summary> 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 } /// <summary> /// Reads GIF file header information /// </summary> 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]; } } /// <summary> /// Reads next frame image /// </summary> 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(); } /// <summary> /// Reads Logical Screen Descriptor /// </summary> 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 } /// <summary> /// Reads Netscape extenstion to obtain iteration count /// </summary> 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()); } /// <summary> /// Reads next 16-bit value, LSB first /// </summary> /// <returns>short read</returns> protected int ReadShort() { // read 16-bit value, LSB first return Read() | (Read() << 8); } /// <summary> /// Resets frame state for reading next image /// </summary> protected void ResetFrame() { lastDispose = dispose; lastRect = new Rectangle(ix, iy, iw, ih); lastImage = image; lastBgColor = bgColor; transparency = false; delay = 0; lct = null; } /// <summary> /// Skips variable length blocks up to and including /// next zero length block /// </summary> protected void Skip() { do { ReadBlock(); } while ((blockSize > 0) && !Error()); } public void Dispose() { image.Dispose(); bitmap.Dispose(); lastImage.Dispose(); }}public class LZWEncoder { static readonly int EOF = -1; int imgW, imgH; byte[] pixAry; int initCodeSize; int remaining; int curPixel; // General DEFINEs static readonly int BITS = 12; static readonly int HSIZE = 5003; // 80% occupancy 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; 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 //---------------------------------------------------------------------------- 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 NeuQuant{ protected static readonly int netsize = 256; // number of colours used // four primes near 500 - assume no image has a length so large // that it is divisible by all four primes protected static readonly int prime1 = 499; protected static readonly int prime2 = 491; protected static readonly int prime3 = 487; protected static readonly int prime4 = 503; protected static readonly int minpicturebytes = (3 * prime4); // minimum size for input image // Program Skeleton /* [select samplefac in range 1..30] [read image from input file] pic = (unsigned char*) malloc(3*width*height); initnet(pic,3*width*height,samplefac); learn(); unbiasnet(); [write output image header, using writecolourmap(f)] inxbuild(); write output image using inxsearch(b,g,r) */ // Network Definitions protected static readonly int maxnetpos = (netsize - 1); protected static readonly int netbiasshift = 4; // bias for colour values protected static readonly int ncycles = 100; // no. of learning cycles // defs for freq and bias */ protected static readonly int intbiasshift = 16; // bias for fractions protected static readonly int intbias = (((int)1) << intbiasshift); protected static readonly int gammashift = 10; // gamma = 1024 protected static readonly int gamma = (((int)1) << gammashift); protected static readonly int betashift = 10; protected static readonly int beta = (intbias >> betashift); // beta = 1/1024 protected static readonly int betagamma = (intbias << (gammashift - betashift)); // defs for decreasing radius factor protected static readonly int initrad = (netsize >> 3); // for 256 cols, radius starts protected static readonly int radiusbiasshift = 6; // at 32.0 biased by 6 bits protected static readonly int radiusbias = (((int)1) << radiusbiasshift); protected static readonly int initradius = (initrad * radiusbias); // and decreases by a 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; 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 { } // 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 { } } } } // 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); }} |
方法四：使用GifEncoder.cs
gifencode.cs
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 | using System;using System.Drawing;using System.Drawing.Imaging;using System.IO;using System.Linq;namespace BumpKit{ /// <summary> /// Encodes multiple images as an animated gif to a stream. <br /> /// ALWAYS ALWAYS ALWAYS wire this up in a using block <br /> /// Disposing the encoder will complete the file. <br /> /// Uses default .net GIF encoding and adds animation headers. /// </summary> public class GifEncoder : IDisposable { #region Header Constants private const string FileType = "GIF"; private const string FileVersion = "89a"; private const byte FileTrailer = 0x3b; private const int ApplicationExtensionBlockIdentifier = 0xff21; private const byte ApplicationBlockSize = 0x0b; private const string ApplicationIdentification = "NETSCAPE2.0"; private const int GraphicControlExtensionBlockIdentifier = 0xf921; private const byte GraphicControlExtensionBlockSize = 0x04; private const long SourceGlobalColorInfoPosition = 10; private const long SourceGraphicControlExtensionPosition = 781; private const long SourceGraphicControlExtensionLength = 8; private const long SourceImageBlockPosition = 789; private const long SourceImageBlockHeaderLength = 11; private const long SourceColorBlockPosition = 13; private const long SourceColorBlockLength = 768; #endregion private bool _isFirstImage = true; private int? _width; private int? _height; private int? _repeatCount; private readonly Stream _stream; // Public Accessors public TimeSpan FrameDelay { get; set; } /// <summary> /// Encodes multiple images as an animated gif to a stream. <br /> /// ALWAYS ALWAYS ALWAYS wire this in a using block <br /> /// Disposing the encoder will complete the file. <br /> /// Uses default .net GIF encoding and adds animation headers. /// </summary> /// <param name="stream">The stream that will be written to.</param> /// <param name="width">Sets the width for this gif or null to use the first frame's width.</param> /// <param name="height">Sets the height for this gif or null to use the first frame's height.</param> public GifEncoder(Stream stream, int? width = null, int? height = null, int? repeatCount = null) { _stream = stream; _width = width; _height = height; _repeatCount = repeatCount; } /// <summary> /// Adds a frame to this animation. /// </summary> /// <param name="img">The image to add</param> /// <param name="x">The positioning x offset this image should be displayed at.</param> /// <param name="y">The positioning y offset this image should be displayed at.</param> public void AddFrame(Image img, int x = 0, int y = 0, TimeSpan? frameDelay = null) { using (var gifStream = new MemoryStream()) { img.Save(gifStream, ImageFormat.Gif); if (_isFirstImage) // Steal the global color table info { InitHeader(gifStream, img.Width, img.Height); } WriteGraphicControlBlock(gifStream, frameDelay.GetValueOrDefault(FrameDelay)); WriteImageBlock(gifStream, !_isFirstImage, x, y, img.Width, img.Height); } _isFirstImage = false; } private void InitHeader(Stream sourceGif, int w, int h) { // File Header WriteString(FileType); WriteString(FileVersion); WriteShort(_width.GetValueOrDefault(w)); // Initial Logical Width WriteShort(_height.GetValueOrDefault(h)); // Initial Logical Height sourceGif.Position = SourceGlobalColorInfoPosition; WriteByte(sourceGif.ReadByte()); // Global Color Table Info WriteByte(0); // Background Color Index WriteByte(0); // Pixel aspect ratio WriteColorTable(sourceGif); // App Extension Header WriteShort(ApplicationExtensionBlockIdentifier); WriteByte(ApplicationBlockSize); WriteString(ApplicationIdentification); WriteByte(3); // Application block length WriteByte(1); WriteShort(_repeatCount.GetValueOrDefault(0)); // Repeat count for images. WriteByte(0); // terminator } private void WriteColorTable(Stream sourceGif) { sourceGif.Position = SourceColorBlockPosition; // Locating the image color table var colorTable = new byte[SourceColorBlockLength]; sourceGif.Read(colorTable, 0, colorTable.Length); _stream.Write(colorTable, 0, colorTable.Length); } private void WriteGraphicControlBlock(Stream sourceGif, TimeSpan frameDelay) { sourceGif.Position = SourceGraphicControlExtensionPosition; // Locating the source GCE var blockhead = new byte[SourceGraphicControlExtensionLength]; sourceGif.Read(blockhead, 0, blockhead.Length); // Reading source GCE WriteShort(GraphicControlExtensionBlockIdentifier); // Identifier WriteByte(GraphicControlExtensionBlockSize); // Block Size WriteByte(blockhead[3] & 0xf7 | 0x08); // Setting disposal flag WriteShort(Convert.ToInt32(frameDelay.TotalMilliseconds / 10)); // Setting frame delay WriteByte(blockhead[6]); // Transparent color index WriteByte(0); // Terminator } private void WriteImageBlock(Stream sourceGif, bool includeColorTable, int x, int y, int h, int w) { sourceGif.Position = SourceImageBlockPosition; // Locating the image block var header = new byte[SourceImageBlockHeaderLength]; sourceGif.Read(header, 0, header.Length); WriteByte(header[0]); // Separator WriteShort(x); // Position X WriteShort(y); // Position Y WriteShort(h); // Height WriteShort(w); // Width if (includeColorTable) // If first frame, use global color table - else use local { sourceGif.Position = SourceGlobalColorInfoPosition; WriteByte(sourceGif.ReadByte() & 0x3f | 0x80); // Enabling local color table WriteColorTable(sourceGif); } else { WriteByte(header[9] & 0x07 | 0x07); // Disabling local color table } WriteByte(header[10]); // LZW Min Code Size // Read/Write image data sourceGif.Position = SourceImageBlockPosition + SourceImageBlockHeaderLength; var dataLength = sourceGif.ReadByte(); while (dataLength > 0) { var imgData = new byte[dataLength]; sourceGif.Read(imgData, 0, dataLength); _stream.WriteByte(Convert.ToByte(dataLength)); _stream.Write(imgData, 0, dataLength); dataLength = sourceGif.ReadByte(); } _stream.WriteByte(0); // Terminator } private void WriteByte(int value) { _stream.WriteByte(Convert.ToByte(value)); } private void WriteShort(int value) { _stream.WriteByte(Convert.ToByte(value & 0xff)); _stream.WriteByte(Convert.ToByte((value >> 8) & 0xff)); } private void WriteString(string value) { _stream.Write(value.ToArray().Select(c => (byte)c).ToArray(), 0, value.Length); } public void Dispose() { // Complete File WriteByte(FileTrailer); // Pushing data _stream.Flush(); } }} |
使用方法：
1 2 3 4 5 6 7 8 9 10 | using (FileStream fs = new FileStream("g:\\gifencoder.gif", FileMode.Create)) using (var encoder = new GifEncoder(fs)) { while (!bStop) { var img = CopyScreen(); //System.Drawing.Image.FromFile("img.png"); encoder.AddFrame(img); Thread.Sleep(200); } } |
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