//// This code is part of Document Solutions for Imaging demos.// Copyright (c) MESCIUS inc. All rights reserved.//using System;using System.IO;using System.Drawing;using GrapeCity.Documents.Imaging;using DsImagingWeb.Demos.Common;
namespace DsImagingWeb.Demos{    // This sample loads an existing GIF with true color frames    // (produced by the MakeGif sample) and converts its frames    // to indexed 8bpp images. It also adds a global palette to the    // resulting GIF (the palette is taken from the first frame).    public class IndexedGif    {        public string DefaultMime { get => Common.Util.MimeTypes.GIF; }
        public Stream GenerateImageStream(string targetMime, Size pixelSize, float dpi, bool opaque, string[] sampleParams = null)        {            if (targetMime != Util.MimeTypes.GIF)                throw new Exception("This sample only supports GIF output format.");
            var ms = new MemoryStream();            // Read frames from the source GIF, convert them to 8bpp and save in the target GIF:            using (var gr = new GcGifReader(Path.Combine("Resources", "Gifs", "goldfish.gif")))            using (var gw = new GcGifWriter(ms))            {                for (int i = 0; i < gr.Frames.Count; ++i)                {                    // Add a global palette to the target GIF based on the first frame:                    if (i == 0)                        using (var tbmp = gr.Frames[i].ToGcBitmap())                            gw.GlobalPalette = tbmp.GenerateOctreePalette(256);
                    var indexedBmp = gr.Frames[i].ReadAsIndexed8bppBitmap();                    gw.AppendFrame(indexedBmp, 0, 0, GifDisposalMethod.DoNotDispose, 16);                }            }            ms.Seek(0, SeekOrigin.Begin);            return ms;        }    }}