'''' This code is part of Document Solutions for Imaging demos.'' Copyright (c) MESCIUS inc. All rights reserved.''Imports System.IOImports System.DrawingImports System.Collections.GenericImports System.LinqImports System.NumericsImports GrapeCity.Documents.DrawingImports GrapeCity.Documents.TextImports GrapeCity.Documents.Imaging
'' 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    Function GenerateImageStream(                ByVal targetMime As String,                ByVal pixelSize As Size,                ByVal dpi As Single,                ByVal opaque As Boolean,                Optional sampleParams As String() = Nothing) As Stream
        If Not targetMime = MimeTypes.GIF Then            Throw New Exception("This sample only supports GIF output format.")        End If
        Dim ms = New MemoryStream()        '' Read frames from the source GIF, convert them to 8bpp And save in the target GIF        Using gr = New GcGifReader(Path.Combine("Resources", "Gifs", "goldfish.gif")), gw = New GcGifWriter(ms)            For i = 0 To gr.Frames.Count - 1                '' Add a global palette to the target GIF based on the first frame                If i = 0 Then                    Using tbmp = gr.Frames(i).ToGcBitmap()                        gw.GlobalPalette = tbmp.GenerateOctreePalette(256)                    End Using                End If                Dim indexedBmp = gr.Frames(i).ReadAsIndexed8bppBitmap()                gw.AppendFrame(indexedBmp, 0, 0, GifDisposalMethod.DoNotDispose, 16)            Next        End Using        ms.Seek(0, SeekOrigin.Begin)        Return ms    End Function
    Public ReadOnly Property DefaultMime() As String        Get            Return MimeTypes.GIF        End Get    End PropertyEnd Class