BadValue at Image/ImageMemXfer/Get triplet, buffered memory.

[fcetrini]

Hi all!
I’m having problem trying the buffered memory image transfer.

I’m working with VB.NET, and I’m currently able to manage sources, retrieve parameters, set capabilities, scan and retrieve image in native mode.

Now, the memory transfer issue:
when the sources notifies TransferReady, I can retrieve the twImageInfo, then correcly setup Tw_SetupMemXFer to retrieve buffer size, then allocate the buffer as needed. When I call the ImageMemXfer/Get, it fails with BadValue status.

Twain specs tell that this status is due to an incorrect buffer size.

This is how I defined the ImageMemXfer class:

 Friend Class Tw_ImageMemXfer

Public Compression As UInt16

Public BytesPerRow As UInt32

Public Columns As UInt32

Public Rows As UInt32

Public XOffset As UInt32

Public YOffset As UInt32

Public BytesWritten As UInt32

Public Memory As Tw_Memory



Public Sub New(ByVal tws As DataStructures.Tw_SetupMemXFer)

Me.Compression = UInt16.MaxValue

Me.BytesPerRow = UInt32.MaxValue

Me.Columns = UInt32.MaxValue

Me.Rows = UInt32.MaxValue

Me.XOffset = UInt32.MaxValue

Me.YOffset = UInt32.MaxValue

Me.BytesWritten = UInt32.MaxValue



Dim lHBuffer As IntPtr = IntPtr.Zero

Dim lBuffer As IntPtr = IntPtr.Zero



lHBuffer = DllImports.kernel32.GlobalAlloc(&H42, tws.Preferred)

lBuffer = DllImports.kernel32.GlobalLock(lHBuffer)



Me.Memory = New Tw_Memory

Me.Memory.Flags = Enumerations.TW_MEMORY_FLAGS.TWMF_APPOWNS Or Enumerations.TW_MEMORY_FLAGS.TWMF_POINTER

Me.Memory.Lenght = tws.Preferred

Me.Memory.TheMem = lBuffer

End Sub



End Class

Please help: what am I doing wrong?

Thank you, Fabio

[peterp]

Me.Memory.Lenght = tws.Preferred <– spelled Length wrong

[Author]

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