/// <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>
/// 合并多个gif动画,在空间坐标上
/// </summary>
/// <param name="sourceGifs">原图像</param>
/// <param name="outPath">合并后图像</param>
public void Merge(List <string> sourceGifs, string outPath)
{
List <List <GifFrame> > frames = new List <List <GifFrame> >();
foreach (string source in sourceGifs)
{
if (!File.Exists(source))
{
throw new IOException(string.Format("文件{0}不存在!", source));
}
using (Bitmap ora_Img = new Bitmap(source))
{
if (ora_Img.RawFormat.Guid != ImageFormat.Gif.Guid)
{
throw new IOException(string.Format("文件{0}!", source));
}
}
GifImage gifImage = GifDecoder.Decode(source);
ThinkDisposalMethod(gifImage);
int index = 0;
foreach (GifFrame f in gifImage.Frames)
{
if (frames.Count <= index)
{
List <GifFrame> list = new List <GifFrame>();
frames.Add(list);
}
List <GifFrame> frameList = frames[index];
frameList.Add(f);
index++;
}
}
List <GifFrame> frameCol = new List <GifFrame>();
int frameIndex = 0;
foreach (List <GifFrame> fs in frames)
{
GifFrame frame = Merge(fs);
frameCol.Add(frame);
if (frame.Image.Width != frameCol[0].Image.Width ||
frame.Image.Height != frameCol[0].Image.Height)
{
frame.ImageDescriptor.XOffSet = frames[frameIndex][0].ImageDescriptor.XOffSet;
frame.ImageDescriptor.YOffSet = frames[frameIndex][0].ImageDescriptor.YOffSet;
frame.GraphicExtension.DisposalMethod = frames[frameIndex][0].GraphicExtension.DisposalMethod;
}
frame.GraphicExtension.Delay = frame.Delay = frames[frameIndex][0].Delay;
frameIndex++;
}
GifImage gifImg = new GifImage();
gifImg.Header = "GIF89a";
LogicalScreenDescriptor lcd = new LogicalScreenDescriptor();
lcd.Width = (short)frameCol[0].Image.Width;
lcd.Height = (short)frameCol[0].Image.Height;
gifImg.LogicalScreenDescriptor = lcd;
ApplicationEx ape = new ApplicationEx();
List <ApplicationEx> apps = new List <ApplicationEx>();
apps.Add(ape);
gifImg.ApplictionExtensions = apps;
gifImg.Frames = frameCol;
GifEncoder.Encode(gifImg, outPath);
}
/// <summary>
/// 对gif图像文件进行解码
/// </summary>
/// <param name="gifPath">gif文件路径</param>
internal static GifImage Decode(string gifPath)
{
FileStream fs = null;
StreamHelper streamHelper = null;
GifImage gifImage = new GifImage();
List <GraphicEx> graphics = new List <GraphicEx>();
int frameCount = 0;
try
{
fs = new FileStream(gifPath, FileMode.Open);
streamHelper = new StreamHelper(fs);
//读取文件头
gifImage.Header = streamHelper.ReadString(6);
//读取逻辑屏幕标示符
gifImage.LogicalScreenDescriptor = streamHelper.GetLCD(fs);
if (gifImage.LogicalScreenDescriptor.GlobalColorTableFlag)
{
//读取全局颜色列表
gifImage.GlobalColorTable = streamHelper.ReadByte(gifImage.LogicalScreenDescriptor.GlobalColorTableSize * 3);
}
int nextFlag = streamHelper.Read();
while (nextFlag != 0)
{
if (nextFlag == GifExtensions.ImageLabel)
{
ReadImage(streamHelper, fs, gifImage, graphics, frameCount);
frameCount++;
}
else if (nextFlag == GifExtensions.ExtensionIntroducer)
{
int gcl = streamHelper.Read();
switch (gcl)
{
case GifExtensions.GraphicControlLabel:
{
GraphicEx graphicEx = streamHelper.GetGraphicControlExtension(fs);
graphics.Add(graphicEx);
break;
}
case GifExtensions.CommentLabel:
{
CommentEx comment = streamHelper.GetCommentEx(fs);
gifImage.CommentExtensions.Add(comment);
break;
}
case GifExtensions.ApplicationExtensionLabel:
{
ApplicationEx applicationEx = streamHelper.GetApplicationEx(fs);
gifImage.ApplictionExtensions.Add(applicationEx);
break;
}
case GifExtensions.PlainTextLabel:
{
PlainTextEx textEx = streamHelper.GetPlainTextEx(fs);
gifImage.PlainTextEntensions.Add(textEx);
break;
}
}
}
else if (nextFlag == GifExtensions.EndIntroducer)
{
//到了文件尾
break;
}
nextFlag = streamHelper.Read();
}
}
catch
{
throw;
}
finally
{
fs.Close();
}
return(gifImage);
}
/// <summary>
/// 合并多个gif文件
/// </summary>
/// <param name="sourceGifs">原图像路径集合</param>
/// <param name="outGif">合并后图像路径</param>
/// <param name="delay">间隔时间</param>
/// <param name="repeat">是否重复播放</param>
public void Merge(List <string> sourceGifs, string outGif, short delay, bool repeat)
{
GifImage gifImage = null;
int index = 0;
short lastDelay = delay;
foreach (string source in sourceGifs)
{
if (!File.Exists(source))
{
throw new IOException(string.Format("文件{0}不存在!", source));
}
using (Bitmap ora_Img = new Bitmap(source))
{
if (ora_Img.RawFormat.Guid != ImageFormat.Gif.Guid)
{
throw new IOException(string.Format("文件{0}!", source));
}
}
GifImage gif = GifDecoder.Decode(source);
if (index == 0)
{
gifImage = gif;
}
int frameCount = 0;
foreach (GifFrame f in gif.Frames)
{
if (frameCount == 0 && f.GraphicExtension.DisposalMethod == 0)
{
f.GraphicExtension.DisposalMethod = 2;
}
if (!f.ImageDescriptor.LctFlag)
{
f.ImageDescriptor.LctSize = f.LocalColorTable.Length / 3;
f.ImageDescriptor.LctFlag = true;
f.GraphicExtension.TranIndex = gif.LogicalScreenDescriptor.BgColorIndex;
f.LocalColorTable = gif.GlobalColorTable;
}
if (frameCount == 0)
{
f.Delay = f.GraphicExtension.Delay = lastDelay;
}
if (f.Delay == 0)
{
f.Delay = f.GraphicExtension.Delay = lastDelay;
}
f.ColorDepth = (byte)(Math.Log(f.ImageDescriptor.LctSize, 2));
lastDelay = f.GraphicExtension.Delay;
frameCount++;
}
gifImage.Frames.AddRange(gif.Frames);
index++;
}
if (repeat && gifImage.ApplictionExtensions.Count == 0)
{
ApplicationEx ae = new ApplicationEx();
gifImage.ApplictionExtensions.Add(ae);
}
gifImage.LogicalScreenDescriptor.PixcelAspect = 0;
Size maxSize = FindMaxSize(sourceGifs);
gifImage.LogicalScreenDescriptor.Width = (short)maxSize.Width;
gifImage.LogicalScreenDescriptor.Height = (short)maxSize.Height;
GifEncoder.Encode(gifImage, outGif);
}