'''' 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 takes a color JPEG, converts it to different image types'' (such as b/w and grayscale) and creates a multi-frame TIFF from those'' images.Public Class ImageTypesInTiff    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.TIFF Then            Throw New Exception("This sample only supports TIFF output format.")        End If
        Dim pth = Path.Combine("Resources", "Images", "minerva.jpg")
        Dim ms = New MemoryStream()        Using tw = New GcTiffWriter(ms),            bmp = New GcBitmap(pth)            '' Using the green channel produces a marginally better result for this photo.            '' For a much better bilevel image produced by dithering, see DitheringInTiff.            Using f = bmp.ToBilevelBitmap(ColorChannel.Green)                tw.AppendFrame(f)            End Using            Using f = bmp.ToGrayscaleBitmap()                tw.AppendFrame(f)            End Using            '' 4bpp allows from 8 to 16 colors, we use max (16)            Using f = bmp.ToIndexed4bppBitmap(16)                tw.AppendFrame(f)            End Using            '' 8bpp allows from 8 to 256 colors, we use max (256)            Using f = bmp.ToIndexed8bppBitmap(256)                tw.AppendFrame(f)            End Using            tw.AppendFrame(bmp)        End Using        ms.Seek(0, SeekOrigin.Begin)        Return ms    End Function
    Public ReadOnly Property DefaultMime() As String        Get            Return MimeTypes.TIFF        End Get    End PropertyEnd Class