示例#1
0
        public static GifImage Decode(Stream fs)
        {
            StreamHelper     streamHelper = null;
            GifImage         gifImage     = new GifImage();
            List <GraphicEx> graphics     = new List <GraphicEx>();
            int frameCount = 0;

            streamHelper = new StreamHelper(fs);

            gifImage.Header = streamHelper.ReadString(6);
            gifImage.LogicalScreenDescriptor = streamHelper.GetLCD(fs);

            if (gifImage.LogicalScreenDescriptor.GlobalColorTableFlag)
            {
                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)
                {
                    break;
                }
                nextFlag = streamHelper.Read();
            }
            return(gifImage);
        }