Hello, all

I am using GDI to read multi-page tiff images and extract certain pages to create an additional multi-page tiff document.

I am referencing the active frames as a bitmap as follows:

'get image format from original tiff file
Me._img.SelectActiveFrame(FrameDimension.Page, fromPageIndex)
pages = New Bitmap(Me._img)

and saving using the saveadd method.

The problem is, when saving to a new tiff file, the file page size is 4 times that of the original (page size, not file size). I have been searching for days for a way to extract information from the original tiff and carry it over to the new tiff, but to no avail.

I understand that when you load the page index to a bitmap, you are decompressing it (stemming from my experience with JAI).

Is there a way to recompress using the compression of the original tiff?

My full code is as follows:

    '/ <summary>
    '/ Saves the specified subpages to the specified file
    '/ </summary>
    Public Sub savePagesInFile(ByVal filename As String, ByVal fromPageIndex As Integer, ByVal toPageIndex As Integer)
        Dim pages As Bitmap = Nothing
        Dim LastPage As Integer = toPageIndex
        Dim lastPageIndex As Integer = _
         Me._img.GetFrameCount(System.Drawing.Imaging.Frame Dimension.Page) - 1

        If (fromPageIndex >= 0) Then
            ' if there are less pages than the specified toPageIndex
            ' toPageIndex is the last page
            If (toPageIndex > lastPageIndex) Then
                toPageIndex = lastPageIndex
            End If

            'get image format from original tiff file
            Me._img.SelectActiveFrame(FrameDimension.Page, fromPageIndex)
            pages = New Bitmap(Me._img)

            'get Image Codec Info
            Dim codec As ImageCodecInfo = getTiffCodec()

            'get encoder to save
            Dim saveEncoder As System.Drawing.Imaging.Encoder = _
             System.Drawing.Imaging.Encoder.SaveFlag

            'get encoderparam to save multi-frame document
            Dim ep As EncoderParameters = New EncoderParameters(1)
            ep.Param(0) = _
             New EncoderParameter(saveEncoder, CLng(EncoderValue.MultiFrame))

            'save first page with Codec Info
            pages.Save(filename, codec, ep)

            'loop through intended pages
            ep.Param(0) = New EncoderParameter(saveEncoder, CLng(EncoderValue.FrameDimensionPage))
            Dim bmp As Bitmap
            For i As Integer = fromPageIndex + 1 To toPageIndex
                'Append each additional page
                Me.appendPageToFile(filename, i, pages)
            Next

            'create flush encoder param
            ep.Param(0) = New EncoderParameter(saveEncoder, CLng(EncoderValue.Flush))

            'flush image
            pages.SaveAdd(ep)
        End If
    End Sub

    '/ <summary>
    '/ Gets the ImageCodecInfo for tiff images
    '/ </summary>
    Protected Function getTiffCodec() As System.Drawing.Imaging.ImageCodecInfo
        Dim info As ImageCodecInfo = Nothing

        For Each ice As ImageCodecInfo In ImageCodecInfo.GetImageEncoders
            If ice.MimeType.ToLower = "image/tiff" Then
                info = ice
            End If
        Next
        Return info
    End Function

    '/ <summary>
    '/ Appends the specified page to the file
    '/ </summary>
    Public Sub appendPageToFile(ByVal fileName As String, ByVal pageIndex As Integer, ByRef pages As Bitmap)
        Dim ep As EncoderParameters = New EncoderParameters(1)

        'get encoder to save
        Dim saveEncoder As System.Drawing.Imaging.Encoder = _
         System.Drawing.Imaging.Encoder.SaveFlag

        ep.Param(0) = New EncoderParameter(saveEncoder, CLng(EncoderValue.FrameDimensionPage))
        Dim bmp As Bitmap

        'Append each additional page
        Me._img.SelectActiveFrame(FrameDimension.Page, pageIndex)
        bmp = New Bitmap(Me._img)
        pages.SaveAdd(bmp, ep)
    End Sub



Thanks for your help



thanks

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thanks