Nikon Coolscan IV ED TWAIN Memory Transfer

[jhmgbl]

Hallo, I have problems with the above Scanner (all other Scanners work fine). In Native Mode the application crashes with an Access violation on

rc = DSixfer(appid, srcds, TwDG.Image, TwDAT.ImageNativeXfer, TwMSG.Get, hbitmap)

and with MemoryTransfer

pImageMemX.BytesWritten

is 0. I assume that perhaps a further initialisation is necessary.

Here is the code:

Public Function TransferPictures() As ArrayList



Dim pics As New ArrayList

If (srcds.Id = IntPtr.Zero) Then

Return pics

End If

Dim rc As TwRC

Dim hbitmap As IntPtr = IntPtr.Zero

Dim pxfr As New TwPendingXfers()





Do

Try

pxfr.Count = 0

hbitmap = IntPtr.Zero



Dim iinf As New TwImageInfo()

Dim iLayout As New TwImageLayout

rc = DSiinf(appid, srcds, TwDG.Image, TwDAT.ImageInfo, TwMSG.Get, iinf)

Dim rc2 As TwRC = DSilayout(appid, srcds, TwDG.Image, TwDAT.ImageLayout, TwMSG.Get, iLayout)

If iinf.PixelType <> TWPT.RGB Then MsgBox("Wrong Pixeltype: " & System.Enum.GetName(GetType(TWPT), CType(iinf.PixelType, TWPT)))

If (rc <> TwRC.Success) Then



CloseSrc()

Return pics



End If



Dim setupMemXfer As New TW_SetupMemXfer()

rc = DsmEntry(appid, srcds, TwMSG.Get, setupMemXfer)

'rc = TwRC.Failure

If rc = TwRC.Success Then

Dim lHasNextBuffer As Boolean = True

Dim pImageMemX As New TwImageMemXFer(setupMemXfer)

pImageMemX.Compression = CUShort(iinf.Compression)

Dim lBuffer, LHBuffer As IntPtr

Dim TotalBytes As UInt32

Dim lMemoryStream As New IO.MemoryStream

Dim fh As New BITMAPFILEHEADER

fh.bfSize = Marshal.SizeOf(fh)

fh.bfType = &H4D42

fh.bfReserved1 = 0

fh.bfReserved2 = 0

fh.bfOffBits = Marshal.SizeOf(fh) + Marshal.SizeOf(GetType(BITMAPINFOHEADER))

Dim bmi As New BITMAPINFOHEADER

bmi.biSize = Marshal.SizeOf(bmi)

bmi.biPlanes = 1

bmi.biBitCount = iinf.BitsPerPixel

bmi.biCompression = iinf.Compression

bmi.biSizeImage = CInt(((((iinf.ImageWidth * iinf.BitsPerPixel + 31) / 32) * 4) * Math.Abs(iinf.ImageLength)))



bmi.biXPelsPerMeter = 0

bmi.biYPelsPerMeter = 0

bmi.biClrUsed = 0

bmi.biClrImportant = 0

bmi.biWidth = iinf.ImageWidth

bmi.biHeight = iinf.ImageLength

lMemoryStream.Seek(0, SeekOrigin.Begin)

Dim pFH, pBMI As IntPtr

Dim FHLength, BMILength As Integer

FHLength = Marshal.SizeOf(fh)

BMILength = Marshal.SizeOf(bmi)

pFH = Marshal.AllocHGlobal(FHLength)

pBMI = Marshal.AllocHGlobal(BMILength)

Marshal.StructureToPtr(fh, pFH, True)

Marshal.StructureToPtr(bmi, pBMI, True)

Dim Arrfh(FHLength - 1) As Byte

Dim ArrBMI(BMILength - 1) As Byte

Marshal.Copy(pFH, Arrfh, 0, FHLength)

Marshal.Copy(pBMI, ArrBMI, 0, BMILength)

lMemoryStream.Write(Arrfh, 0, FHLength)

lMemoryStream.Write(ArrBMI, 0, BMILength)

Marshal.FreeHGlobal(pFH)

Marshal.FreeHGlobal(pBMI)



LHBuffer = GlobalAlloc(&H42, CInt(setupMemXfer.preferred))

lBuffer = GlobalLock(LHBuffer)

pImageMemX.Memory.TheMem = lBuffer



While lHasNextBuffer

Select Case DSmemxfer(appid, srcds, TwDG.Image, TwDAT.ImageMemXfer, TwMSG.Get, pImageMemX)



Case TwRC.Success

If pImageMemX.BytesWritten = 0 Then lHasNextBuffer = False : Exit Select

Dim lByteArray As Byte() = New Byte(CInt(pImageMemX.BytesWritten - 1)) {}



Marshal.Copy(lBuffer, lByteArray, 0, lByteArray.Length)

Debug.Print(CStr(pImageMemX.Memory.Length))

TotalBytes = TotalBytes + pImageMemX.BytesWritten

lMemoryStream.Write(lByteArray, 0, lByteArray.Length)



Dim lMessage As String = String.Format("pimagememx.BytesWritten = {0}", pImageMemX.BytesWritten)

Debug.Print(lMessage)



' Free the current buffer

GlobalUnlock(lBuffer)

GlobalFree(LHBuffer)



LHBuffer = IntPtr.Zero

lBuffer = IntPtr.Zero



LHBuffer = GlobalAlloc(&H42, CInt(setupMemXfer.preferred))

lBuffer = GlobalLock(LHBuffer)



pImageMemX = New TwImageMemXFer(setupMemXfer)

pImageMemX.Memory.TheMem = lBuffer







Exit Select

Case TwRC.XferDone

Dim lByteArray1 As Byte() = New Byte(CInt(pImageMemX.BytesWritten - 1)) {}





Dim lMessage As String = String.Format("pimagememx.BytesWritten = {0}", pImageMemX.BytesWritten)

Debug.Print(lMessage)

Marshal.Copy(lBuffer, lByteArray1, 0, lByteArray1.Length)



TotalBytes = TotalBytes + pImageMemX.BytesWritten

lMemoryStream.Write(lByteArray1, 0, lByteArray1.Length)

Try

Dim img As Image = Image.FromStream(lMemoryStream)

img.RotateFlip(RotateFlipType.RotateNoneFlipY)

lMemoryStream.Close()

GlobalUnlock(lBuffer)

GlobalFree(LHBuffer)

Dim b As Bitmap = DirectCast(img, Bitmap)

Dim width As Integer = img.Width

Dim height As Integer = img.Height

Dim data As BitmapData = b.LockBits(New Rectangle(0, 0, width, height), ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb)

Dim offset As Integer = data.Stride - data.Width * 3

Dim offs As Integer

Dim ptr As IntPtr = data.Scan0

Dim y As Integer = 0

While y < height

Dim x As Integer = 0

While x < width

Dim swap As Byte = Marshal.ReadByte(ptr, offs)

Marshal.WriteByte(ptr, offs, Marshal.ReadByte(ptr, offs + 2))

Marshal.WriteByte(ptr, offs + 2, swap)

x += 1

offs += 3

End While

y += 1

offs += offset

End While

b.UnlockBits(data)



pics.Add(img)

Catch ex As Exception

MsgBox(ex.Message)

End Try

rc = DSpxfer(appid, srcds, TwDG.Control, TwDAT.PendingXfers, TwMSG.EndXfer, pxfr)

If (rc <> TwRC.Success) Then

CloseSrc()

Return pics

End If



lHasNextBuffer = False

Exit Select



Case TwRC.Cancel

Exit Select

Case TwRC.Failure

Exit Select



End Select

End While

Else

Try

rc = DSixfer(appid, srcds, TwDG.Image, TwDAT.ImageNativeXfer, TwMSG.Get, hbitmap)

Catch

End Try

'hbitmap = CType(ptrBitmap, IntPtr)

If (rc <> TwRC.XferDone) Then



CloseSrc()

Return pics

End If



rc = DSpxfer(appid, srcds, TwDG.Control, TwDAT.PendingXfers, TwMSG.EndXfer, pxfr)

If (rc <> TwRC.Success) Then



CloseSrc()

Return pics

End If



pics.Add(hbitmap)

End If



Catch ex As Exception

MsgBox(ex.Message)

CloseSrc()

Return pics

End Try

Loop While pxfr.Count <> 0





rc = DSpxfer(appid, srcds, TwDG.Control, TwDAT.PendingXfers, TwMSG.Reset, pxfr)

Return pics



End Function

And in C#

public ArrayList TransferPictures()

{



ArrayList pics = new ArrayList();

if ((srcds.Id == IntPtr.Zero)) {

return pics;

}

TwRC rc = default(TwRC);

IntPtr hbitmap = IntPtr.Zero;

TwPendingXfers pxfr = new TwPendingXfers();





do {

try {

pxfr.Count = 0;

hbitmap = IntPtr.Zero;



TwImageInfo iinf = new TwImageInfo();

TwImageLayout iLayout = new TwImageLayout();

rc = DSiinf(appid, srcds, TwDG.Image, TwDAT.ImageInfo, TwMSG.Get, iinf);

TwRC rc2 = DSilayout(appid, srcds, TwDG.Image, TwDAT.ImageLayout, TwMSG.Get, iLayout);

if (iinf.PixelType != TWPT.RGB)

Interaction.MsgBox("Wrong Pixeltype: " + System.Enum.GetName(typeof(TWPT), (TWPT)iinf.PixelType));



if ((rc != TwRC.Success)) {

CloseSrc();

return pics;



}



TW_SetupMemXfer setupMemXfer = new TW_SetupMemXfer();

rc = DsmEntry(appid, srcds, TwMSG.Get, setupMemXfer);

//rc = TwRC.Failure

if (rc == TwRC.Success) {

bool lHasNextBuffer = true;

TwImageMemXFer pImageMemX = new TwImageMemXFer(setupMemXfer);

pImageMemX.Compression = Convert.ToUInt16(iinf.Compression);

IntPtr lBuffer = default(IntPtr);

IntPtr LHBuffer = default(IntPtr);

UInt32 TotalBytes = default(UInt32);

System.IO.MemoryStream lMemoryStream = new System.IO.MemoryStream();

BITMAPFILEHEADER fh = new BITMAPFILEHEADER();

fh.bfSize = Marshal.SizeOf(fh);

fh.bfType = 0x4d42;

fh.bfReserved1 = 0;

fh.bfReserved2 = 0;

fh.bfOffBits = Marshal.SizeOf(fh) + Marshal.SizeOf(typeof(BITMAPINFOHEADER));

BITMAPINFOHEADER bmi = new BITMAPINFOHEADER();

bmi.biSize = Marshal.SizeOf(bmi);

bmi.biPlanes = 1;

bmi.biBitCount = iinf.BitsPerPixel;

bmi.biCompression = iinf.Compression;

bmi.biSizeImage = Convert.ToInt32(((((iinf.ImageWidth * iinf.BitsPerPixel + 31) / 32) * 4) * Math.Abs(iinf.ImageLength)));



bmi.biXPelsPerMeter = 0;

bmi.biYPelsPerMeter = 0;

bmi.biClrUsed = 0;

bmi.biClrImportant = 0;

bmi.biWidth = iinf.ImageWidth;

bmi.biHeight = iinf.ImageLength;

lMemoryStream.Seek(0, SeekOrigin.Begin);

IntPtr pFH = default(IntPtr);

IntPtr pBMI = default(IntPtr);

int FHLength = 0;

int BMILength = 0;

FHLength = Marshal.SizeOf(fh);

BMILength = Marshal.SizeOf(bmi);

pFH = Marshal.AllocHGlobal(FHLength);

pBMI = Marshal.AllocHGlobal(BMILength);

Marshal.StructureToPtr(fh, pFH, true);

Marshal.StructureToPtr(bmi, pBMI, true);

byte[] Arrfh = new byte[FHLength];

byte[] ArrBMI = new byte[BMILength];

Marshal.Copy(pFH, Arrfh, 0, FHLength);

Marshal.Copy(pBMI, ArrBMI, 0, BMILength);

lMemoryStream.Write(Arrfh, 0, FHLength);

lMemoryStream.Write(ArrBMI, 0, BMILength);

Marshal.FreeHGlobal(pFH);

Marshal.FreeHGlobal(pBMI);



LHBuffer = GlobalAlloc(0x42, Convert.ToInt32(setupMemXfer.preferred));

lBuffer = GlobalLock(LHBuffer);

pImageMemX.Memory.TheMem = lBuffer;



while (lHasNextBuffer) {

switch (DSmemxfer(appid, srcds, TwDG.Image, TwDAT.ImageMemXfer, TwMSG.Get, pImageMemX)) {



case TwRC.Success:

if (pImageMemX.BytesWritten == 0){lHasNextBuffer = false;break; // TODO: might not be correct. Was : Exit Select

}

byte[] lByteArray = new byte[Convert.ToInt32(pImageMemX.BytesWritten - 1) + 1];



Marshal.Copy(lBuffer, lByteArray, 0, lByteArray.Length);

Debug.Print(Convert.ToString(pImageMemX.Memory.Length));

TotalBytes = TotalBytes + pImageMemX.BytesWritten;

lMemoryStream.Write(lByteArray, 0, lByteArray.Length);



string lMessage = string.Format("pimagememx.BytesWritten = {0}", pImageMemX.BytesWritten);

Debug.Print(lMessage);



// Free the current buffer

GlobalUnlock(lBuffer);

GlobalFree(LHBuffer);



LHBuffer = IntPtr.Zero;

lBuffer = IntPtr.Zero;



LHBuffer = GlobalAlloc(0x42, Convert.ToInt32(setupMemXfer.preferred));

lBuffer = GlobalLock(LHBuffer);



pImageMemX = new TwImageMemXFer(setupMemXfer);

pImageMemX.Memory.TheMem = lBuffer;







break; // TODO: might not be correct. Was : Exit Select



break;

case TwRC.XferDone:

byte[] lByteArray1 = new byte[Convert.ToInt32(pImageMemX.BytesWritten - 1) + 1];





string lMessage = string.Format("pimagememx.BytesWritten = {0}", pImageMemX.BytesWritten);

Debug.Print(lMessage);

Marshal.Copy(lBuffer, lByteArray1, 0, lByteArray1.Length);



TotalBytes = TotalBytes + pImageMemX.BytesWritten;

lMemoryStream.Write(lByteArray1, 0, lByteArray1.Length);

try {

Image img = Image.FromStream(lMemoryStream);

img.RotateFlip(RotateFlipType.RotateNoneFlipY);

lMemoryStream.Close();

GlobalUnlock(lBuffer);

GlobalFree(LHBuffer);

Bitmap b = (Bitmap)img;

int width = img.Width;

int height = img.Height;

BitmapData data = b.LockBits(new Rectangle(0, 0, width, height), ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb);

int offset = data.Stride - data.Width * 3;

int offs = 0;

IntPtr ptr = data.Scan0;

int y = 0;

while (y < height) {

int x = 0;

while (x < width) {

byte swap = Marshal.ReadByte(ptr, offs);

Marshal.WriteByte(ptr, offs, Marshal.ReadByte(ptr, offs + 2));

Marshal.WriteByte(ptr, offs + 2, swap);

x += 1;

offs += 3;

}

y += 1;

offs += offset;

}

b.UnlockBits(data);



pics.Add(img);

} catch (Exception ex) {

Interaction.MsgBox(ex.Message);

}

rc = DSpxfer(appid, srcds, TwDG.Control, TwDAT.PendingXfers, TwMSG.EndXfer, pxfr);

if ((rc != TwRC.Success)) {

CloseSrc();

return pics;

}



lHasNextBuffer = false;

break; // TODO: might not be correct. Was : Exit Select





break;

case TwRC.Cancel:

break; // TODO: might not be correct. Was : Exit Select



break;

case TwRC.Failure:

break; // TODO: might not be correct. Was : Exit Select





break;

}

}

} else {

try {

rc = DSixfer(appid, srcds, TwDG.Image, TwDAT.ImageNativeXfer, TwMSG.Get, hbitmap);

} catch {

}

//hbitmap = CType(ptrBitmap, IntPtr)



if ((rc != TwRC.XferDone)) {

CloseSrc();

return pics;

}



rc = DSpxfer(appid, srcds, TwDG.Control, TwDAT.PendingXfers, TwMSG.EndXfer, pxfr);



if ((rc != TwRC.Success)) {

CloseSrc();

return pics;

}



pics.Add(hbitmap);

}



} catch (Exception ex) {

Interaction.MsgBox(ex.Message);

CloseSrc();

return pics;

}

} while (pxfr.Count != 0);





rc = DSpxfer(appid, srcds, TwDG.Control, TwDAT.PendingXfers, TwMSG.Reset, pxfr);

return pics;



}

Regards Hans

[jhmgbl]

I got the code working by setting the following capability:

If Me.blnMemXFer Then SetCap(TwCap.IXferMech, twsx.MEMORY) Else SetCap(TwCap.IXferMech, twsx.NATIVE)

The only problem is now that if PixelType is Grey the image gets distortet.

Regards

Hans

[spike]

What’s the distortion look like?
Are you taking account of the fact that in a bitmap (DIB) the size of each row is a multiple of 4 bytes?
I see you using that to calculate the size of the DIB, but I don’t see you padding each row up to a multiple of 4 bytes when you copy data from the buffer during memory transfer.
Also, Windows has no concept of grayscale DIB – grayscale images are managed as 256-color DIBs. So there has to be a 256-entry color table after the header, and I don’t see that either.
I just skimmed the code, I’m sorry if I missed something!

[Author]

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