version update
This commit is contained in:
562
Res/Gif.Components/AnimatedGifEncoder.cs
Executable file
562
Res/Gif.Components/AnimatedGifEncoder.cs
Executable file
@@ -0,0 +1,562 @@
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using System;
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using System.IO;
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using SkiaSharp;
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namespace Gif.Components
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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 SKColor transparent = SKColor.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 MemoryStream ms;
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// protected FileStream fs;
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protected SKBitmap 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(SKColor 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(SKBitmap 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)
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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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ms.WriteByte(0x3b); // gif trailer
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ms.Flush();
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if (closeStream)
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{
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// ms.Close();
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}
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}
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catch (IOException)
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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(MemoryStream 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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ms = 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)
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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 to a memory stream.
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*
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* @return false if open or initial write failed.
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*/
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public bool Start()
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{
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bool ok;
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try
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{
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ok = Start(new MemoryStream(10 * 1024));
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closeStream = true;
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}
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catch (IOException)
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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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* @return false if open or initial write failed.
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*/
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public bool Output(string file)
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{
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try
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{
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FileStream fs = new FileStream(file, FileMode.OpenOrCreate, FileAccess.Write, FileShare.None);
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fs.Write(ms.ToArray(), 0, (int)ms.Length);
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fs.Close();
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}
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catch (IOException)
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{
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return false;
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}
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return true;
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}
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public MemoryStream Output()
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{
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return ms;
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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 != SKColor.Empty)
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{
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//transIndex = FindClosest(transparent);
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transIndex = nq.Map(transparent.Blue, transparent.Green, transparent.Red);
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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(SKColor c)
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{
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if (colorTab == null) return -1;
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int r = c.Red;
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int g = c.Green;
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int b = c.Blue;
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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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var temp = new SKBitmap(width, height);
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var canvas = new SKCanvas(temp);
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canvas.DrawBitmap(image, 0, 0);
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image = temp;
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canvas.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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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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var color = image.GetPixel(tw, th);
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pixels[count] = color.Red;
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count++;
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pixels[count] = color.Green;
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count++;
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pixels[count] = color.Blue;
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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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ms.WriteByte(0x21); // extension introducer
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ms.WriteByte(0xf9); // GCE label
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ms.WriteByte(4); // data block size
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int transp, disp;
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if (transparent == SKColor.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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ms.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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ms.WriteByte(Convert.ToByte(transIndex)); // transparent color index
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ms.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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ms.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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ms.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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ms.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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ms.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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ms.WriteByte(0); // background color index
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ms.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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ms.WriteByte(0x21); // extension introducer
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ms.WriteByte(0xff); // app extension label
|
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ms.WriteByte(11); // block size
|
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WriteString("NETSCAPE" + "2.0"); // app id + auth code
|
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ms.WriteByte(3); // sub-block size
|
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ms.WriteByte(1); // loop sub-block id
|
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WriteShort(repeat); // loop count (extra iterations, 0=repeat forever)
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ms.WriteByte(0); // block terminator
|
||||
}
|
||||
|
||||
/**
|
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* Writes color table
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*/
|
||||
protected void WritePalette()
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{
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ms.Write(colorTab, 0, colorTab.Length);
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||||
int n = (3 * 256) - colorTab.Length;
|
||||
for (int i = 0; i < n; i++)
|
||||
{
|
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ms.WriteByte(0);
|
||||
}
|
||||
}
|
||||
|
||||
/**
|
||||
* Encodes and writes pixel data
|
||||
*/
|
||||
protected void WritePixels()
|
||||
{
|
||||
LZWEncoder encoder =
|
||||
new LZWEncoder(width, height, indexedPixels, colorDepth);
|
||||
encoder.Encode(ms);
|
||||
}
|
||||
|
||||
/**
|
||||
* Write 16-bit value to output stream, LSB first
|
||||
*/
|
||||
protected void WriteShort(int value)
|
||||
{
|
||||
ms.WriteByte(Convert.ToByte(value & 0xff));
|
||||
ms.WriteByte(Convert.ToByte((value >> 8) & 0xff));
|
||||
}
|
||||
|
||||
/**
|
||||
* Writes string to output stream
|
||||
*/
|
||||
protected void WriteString(string s)
|
||||
{
|
||||
char[] chars = s.ToCharArray();
|
||||
for (int i = 0; i < chars.Length; i++)
|
||||
{
|
||||
ms.WriteByte((byte)chars[i]);
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
}
|
||||
Reference in New Issue
Block a user