DATATRANSFER

Summary

The DATATRANSFER structure provides information about data transferring.

Syntax

typedef struct _DATATRANSFER 
{ 
   L_UINT uStructSize; 
   L_INT nFillOrder; 
   L_INT nBufMemCompression; 
   L_INT nTransferMode; 
   L_INT nScanFileFormat; 
   L_INT nMemBufSize; 
   L_BOOL bSaveToOneFile; 
   L_BOOL bAppendToFile; 
   L_BOOL bDumpMemBufsToFile; 
   L_TCHAR szFileName [250]; 
} DATATRANSFER,  * pDATATRANSFER; 

Members

L_UINT uStructSize

Size of the DATATRANSFER structure, in bytes, for versioning. Use the sizeof() operator to calculate the value.

L_INT nFillOrder

Indicates how bytes in the image are to be filled by the source. Possible values are (according to the TWAIN specification):

L_INT nBufMemCompression

Specifies the compression to be used when having the transfer mode set to be memory. Possible values are (according to the TWAIN specification):

L_INT nTransferMode

Transfer mode to be used by the TWAIN source. Possible values are (according to the TWAIN specification):

L_INT nScanFileFormat

Determines the file format to use when saving the files from the TWAIN source when nTransferMode is TWSX_FILE. Possible values are (according to the TWAIN specification) :

L_INT nMemBufSize

Specifies the memory buffer size to be used in data transfer.

L_BOOL bSaveToOneFile

Flag that indicates whether to save multiple pages to a single file. Possible values are:

L_BOOL bAppendToFile

Flag that indicates whether to append pages to the end of the file when saving a multipage file. Possible values are:

L_BOOL bDumpMemBufsToFile

Flag that indicates whether to use the file name specified in szFileName field to dump the memory buffers received from the scanner. In this case the Bitmap Handle will not get the Bitmap Data: all the data will be saved to the file. Possible values:

L_TCHAR szFileName

Character string that contains the file name used in the file transfer mode. Use this member only if:

The nTransferMode member is set to TWSX_FILE.

Or

The nTransferMode member is set to TWSX_MEMORY and the bDumpMemBufsToFile member is set to TRUE.

Comments

pDATATRANSFER is a pointer to a DATATRANSFER structure. Where the function parameter type is pDATATRANSFER, you can declare a DATATRANSFER variable, update the structure's fields and pass the variable's address in the parameter. Declaring a pDATATRANSFER variable is necessary only if your program requires a pointer.

If the nTransferMode member value is set to TWSX_MEMORY and the bDumpMemBufsToFile member value is set to TRUE, then the LTwain::Acquire and LTwain::AcquireList functions will dump the memory buffers received from the scanner (whether compressed or not) directly to the output file specified by szFileName member.

If the nTransferMode member value is set to TWSX_MEMORY, the nBufMemCompression member is set to values other than TWCP_NONE, and the bDumpMemBufsToFile member value is set to FALSE, then the LTwain::Acquire and LTwain::AcquireList functions will decompress the memory buffers received from the scanner, and generate a BITMAPHANDLE as a result.

This generated BITMAPHANDLE will be:

• Returned in the pBitmap parameter of LTwain::BitmapCallBack function when it is fired by calling the LTwain::Acquire function

Or

• Added to the bitmap list specified by hBitmap and BitmapList parameters of the LTwain::AcquireList function when this function is being used.

Usage

• LTWAINPROPERTIES