ImageToByte does not work as expected with ccitt t.6

Question

ImageToByte function take an array of bytes for each page of a multipage tiff. The purpose of this is to create a single page tiff that contains all pages of the original tiff.

My code works perfectly except with tiffs with compression ccitt t.6. When I pass every page of this multipage tiff to ImageToByte function, it returns me a byte array corresponding to a completely black image.

Private Function ImageToByte(bImagen As System.Drawing.Image) As Byte()
    Dim codec As ImageCodecInfo = GetEncoderInfo("image/tiff")
    Dim enc As Encoder = System.Drawing.Imaging.Encoder.SaveFlag
    Dim ep As New EncoderParameters(2)

    ep.Param(0) = New EncoderParameter(enc, EncoderValue.FrameDimensionPage)
    ep.Param(1) = New EncoderParameter(Encoder.Compression, EncoderValue.CompressionNone)

    Using ms As New MemoryStream
        bImagen.Save(ms, codec, ep)
        ImageToByte = ms.ToArray
    End Using
End Function

Private Shared Function GetEncoderInfo(ByVal mimeType As String) As ImageCodecInfo
    Dim j As Integer
    Dim encoders() As ImageCodecInfo
    encoders = ImageCodecInfo.GetImageEncoders()

    j = 0
    While j < encoders.Length
        If encoders(j).MimeType = mimeType Then
            Return encoders(j)
        End If
        j += 1
    End While
    Return Nothing

End Function

Could someone tell me how to fix this issue?

Chase Rocker Chase Rocker · Accepted Answer · 2014-10-13T08:03:30

From the code you've posted, you're not passing anything back from the ImageToByte function.

Unless you miss-typed and ByteToImage is supposed to be ImageToByte.

Using ms As New MemoryStream
    bImagen.Save(ms, codec, ep)
    ByteToImage = ms.ToArray
End Using

ImageToByte does not work as expected with ccitt t.6

1 Answers