Memory Transfer Mode

[gshewale]

Hi,
I am trying to implement the memory transfer mode, and I have this issue:
Sometimes the images get scanned correctly and sometimes they get stretched
On investigation, I found that the image size obtained from calculation (lBitmapInfo.BmiHeader.biSizeImage = (UInt32)((((lImageInfo.ImageWidth * lImageInfo.BitsPerPixel + 31) / 32) * 4) * lImageInfo.ImageLength);)

is different from the summation of ImageMemXfer.BytesWritten.

if the differenc is 0, then I am getting perfect images.

The x and y resolution of the images are same.

What might be the reason for this behaviour?
The code in c# is given below.

Thanks in advance.
Girish
[/quote]

while (lHasNextBuffer)

{





switch (_TripletContainer.DataGroup.TWImage.TWImageMemXfer.Get(ref lImageMemXfer))

{

case ReturnCodesEnum.Success:



byte[] lByteArray = new byte[lImageMemXfer.BytesWritten];



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



totalbytes = totalbytes + lImageMemXfer.BytesWritten;

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



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

_LoggingService.WriteLog(lMessage, 2, lLogTitle,

lLogModuleName, lLogMethodName,

lLogCreatedBy, lLogSessionID);





// Free the current buffer

Kernel32.GlobalUnlock(lBuffer);

Kernel32.GlobalFree(lHBuffer);



lHBuffer = IntPtr.Zero;

lBuffer = IntPtr.Zero;



lHBuffer = Kernel32.GlobalAlloc(0x42, lSetupMemXfer.Preferred);

lBuffer = Kernel32.GlobalLock(lHBuffer);



lImageMemXfer = new ImageMemXfer();

lImageMemXfer.Memory.Flags = (uint)(MemoryEnum.AppOwns | MemoryEnum.Pointer);

lImageMemXfer.Memory.Length = lSetupMemXfer.Preferred;

lImageMemXfer.Memory.TheMem = lBuffer;

lImageMemXfer.Compression = (ushort)On16Enum.twDontCare16;

lImageMemXfer.BytesPerRow = (uint)On32Enum.twDontCare32;

lImageMemXfer.Columns = (uint)On32Enum.twDontCare32;

lImageMemXfer.Rows = (uint)On32Enum.twDontCare32;

lImageMemXfer.XOffset = (uint)On32Enum.twDontCare32;

lImageMemXfer.YOffset = (uint)On32Enum.twDontCare32;

lImageMemXfer.BytesWritten = (uint)On32Enum.twDontCare32;







break;

case ReturnCodesEnum.XferDone:



byte[] lByteArray1 = new byte[lImageMemXfer.BytesWritten];



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

_LoggingService.WriteLog(lMessage, 2, lLogTitle,

lLogModuleName, lLogMethodName,

lLogCreatedBy, lLogSessionID);



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



totalbytes = totalbytes + lImageMemXfer.BytesWritten;





long Diffrence = lBitmapInfo.BmiHeader.biSizeImage - totalbytes;





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



lFileName = NextAvailableFilename(lSessionDir.FullName, _CurrentImageFileFormat.ToString().ToLower());



//DIB.BitmapFromDIB(lMemoryStream).Save(lFileName);

DIB.BitmapFromDIB(lMemoryStream).Save(lFileName);



lMessage = string.Format("Memory Transfer Done for Image Name {0}", lFileName);

_LoggingService.WriteLog(lMessage, 2, lLogTitle,

lLogModuleName, lLogMethodName,

lLogCreatedBy, lLogSessionID);



lMessage = string.Format("TotalBytes received from Scanner = {0}, Bitmap size from ImageInfo = {1}, Difference = {2} ", totalbytes, lBitmapInfo.BmiHeader.biSizeImage, Diffrence);

_LoggingService.WriteLog(lMessage, 2, lLogTitle,

lLogModuleName, lLogMethodName,

lLogCreatedBy, lLogSessionID);



lMemoryStream.Close();

Kernel32.GlobalUnlock(lBuffer);

Kernel32.GlobalFree(lHBuffer);



_Images.Add(lFileName);

lPendingXfers = DoEndXfer();

lHasNextBuffer = false;

break;



case ReturnCodesEnum.Cancel:

break;

case ReturnCodesEnum.Failure:

break;



}

}

[MSM]

Hi,
I would recommend you to update ImageInfo (DG_IMAGE / DAT_IMAGEINFO/MSG_GET) after you received ReturnCodesEnum.XferDone, but before you do DoEndXfer();

Pay attantion the fact that some DS does not support DG_IMAGE / DAT_IMAGEINFO/MSG_GET in state 7 (after you start transfering).

So you will need one DG_IMAGE / DAT_IMAGEINFO/MSG_GET before your first “_TripletContainer.DataGroup.TWImage.TWImageMemXfer.Get” (I suppose where it is now) and one just after “case ReturnCodesEnum.XferDone:” . If second call succeeds then use its data to update bitmap header.

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