static void ReadImage(StreamHelper streamHelper, Stream fs, GifImage gifImage, List <GraphicEx> graphics, int frameCount)
{
ImageDescriptor imgDes = streamHelper.GetImageDescriptor(fs);
GifFrame frame = new GifFrame();
frame.ImageDescriptor = imgDes;
frame.LocalColorTable = gifImage.GlobalColorTable;
if (imgDes.LctFlag)
{
frame.LocalColorTable = streamHelper.ReadByte(imgDes.LctSize * 3);
}
LZWDecoder lzwDecoder = new LZWDecoder(fs);
int dataSize = streamHelper.Read();
frame.ColorDepth = dataSize;
byte[] piexel = lzwDecoder.DecodeImageData(imgDes.Width, imgDes.Height, dataSize);
frame.IndexedPixel = piexel;
int blockSize = streamHelper.Read();
DataStruct data = new DataStruct(blockSize, fs);
if (graphics.Count > frameCount)
{
GraphicEx graphicEx = graphics[frameCount];
frame.GraphicExtension = graphicEx;
}
Bitmap img = GetImageFromPixel(piexel, frame.Palette, imgDes.InterlaceFlag, imgDes.Width, imgDes.Height);
frame.Image = img;
gifImage.Frames.Add(frame);
}
/// <summary>
/// 从文件流中读取应用程序扩展块
/// </summary>
/// <param name="stream"></param>
/// <returns></returns>
internal ApplicationEx GetApplicationEx(Stream stream)
{
ApplicationEx appEx = new ApplicationEx();
int blockSize = Read();
if (blockSize != ApplicationEx.BlockSize)
{
throw new Exception("数据格式错误！");
}
appEx.ApplicationIdentifier = ReadChar(8);
appEx.ApplicationAuthenticationCode = ReadChar(3);
int nextFlag = Read();
appEx.Datas = new List<DataStruct>();
while (nextFlag != 0)
{
DataStruct data = new DataStruct(nextFlag, stream);
appEx.Datas.Add(data);
nextFlag = Read();
}
return appEx;
}
/// <summary>
/// 从文件流中读取应用程序扩展块
/// </summary>
/// <param name="stream"></param>
/// <returns></returns>
public ApplicationEx GetApplicationEx(Stream stream)
{
ApplicationEx appEx = new ApplicationEx();
int blockSize = Read();
if (blockSize != ApplicationEx.BlockSize)
{
throw new Exception("数据格式错误！");
}
appEx.ApplicationIdentifier = ReadChar(8);
appEx.ApplicationAuthenticationCode = ReadChar(3);
int nextFlag = Read();
appEx.Datas = new List <DataStruct>();
while (nextFlag != 0)
{
DataStruct data = new DataStruct(nextFlag, stream);
appEx.Datas.Add(data);
nextFlag = Read();
}
return(appEx);
}
static void ReadImage(StreamHelper streamHelper, Stream fs, GifImage gifImage, List<GraphicEx> graphics, int frameCount)
{
ImageDescriptor imgDes = streamHelper.GetImageDescriptor(fs);
GifFrame frame = new GifFrame();
frame.ImageDescriptor = imgDes;
frame.LocalColorTable = gifImage.GlobalColorTable;
if (imgDes.LctFlag)
{
frame.LocalColorTable = streamHelper.ReadByte(imgDes.LctSize*3);
}
LZWDecoder lzwDecoder = new LZWDecoder(fs);
int dataSize = streamHelper.Read();
frame.ColorDepth = dataSize;
byte[] piexel = lzwDecoder.DecodeImageData(imgDes.Width, imgDes.Height, dataSize);
frame.IndexedPixel = piexel;
int blockSize = streamHelper.Read();
DataStruct data = new DataStruct(blockSize, fs);
GraphicEx graphicEx = graphics[frameCount];
frame.GraphicExtension = graphicEx;
Bitmap img = GetImageFromPixel(piexel, frame.Palette, imgDes.InterlaceFlag, imgDes.Width, imgDes.Height);
frame.Image = img;
gifImage.Frames.Add(frame);
}
