LWIADATATRANSFER

typedef struct _LWIADATATRANSFER 
{ 
   L_UINT uStructSize; 
   GUID * pguidFormat; 
   L_INT nCompression; 
   L_INT nTransferMode; 
   L_INT nImageDataType; 
} LWIADATATRANSFER,   * pLWIADATATRANSFER; 

The LWIADATATRANSFER structure provides information about data transfer.

Members

uStructSize

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

pguidFormat

Contains the preferred format of the image when transferred from the device.

For a list of all available transfer formats, refer to the Microsoft Windows SDK Documentation for the WIA_IPA_FORMAT property ID.

nCompression

Contains the preferred compression type to be used when transferring data from the device.

For a list of all available compressions, refer to the Microsoft Windows SDK Documentation for the WIA_IPA_COMPRESSION property ID.

nTransferMode

Transfer mode to be used by the WIA source. Possible values are:

Value Meaning
TYMED_CALLBACK Memory buffered transfer mode. The source will be transferring strips of data to the application according to the buffer size given. This is the default value.
TYMED_FILE File transfer mode. The file specified in the szFileName member of the LWIAACQUIREOPTIONS structure passed to any of the available acquire functions will be transferred.

Make sure that the passed transfer format in the pguidFormat member of LWIADATATRANSFER is the same as the one specified through the LWIAACQUIREOPTIONS structure, since the acquire functions always use the one passed through the LWIAACQUIREOPTIONS structure.

nImageDataType

Contains the preferred data type for the image when transferred from the device.

For a list of all available compressions, refer to the Microsoft Windows SDK Documentation for the WIA_IPA_DATATYPE property ID.

Comments

This feature is available in LEADTOOLS version 16 or higher.

pLWIADATATRANSFER is a pointer to an LWIADATATRANSFER structure. If the function parameter type is pLWIADATATRANSFER, declare a LWIADATATRANSFER variable, update the structure's fields and pass the variable's address in the parameter. Declaring a pLWIADATATRANSFER variable is necessary only if your program requires a pointer.

LWIADATATRANSFER is used with the LWIAPROPERTIES structure.

If the nTransferMode member value is set to TYMED_CALLBACK, the acquire functions use 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 the LWia::AcquireCallBack callback when it is fired by calling the LWia::Acquire or LWia::AcquireSimple functions.

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