WIA_DATA_CALLBACK_HEADER structure (wia_xp.h)

The WIA_DATA_CALLBACK_HEADER is transmitted to an application during a series of calls by the Windows Image Acquisition (WIA) run-time system to the IWiaDataCallback::BandedDataCallback method.

Syntax

typedef struct _WIA_DATA_CALLBACK_HEADER {
  LONG lSize;
  GUID guidFormatID;
  LONG lBufferSize;
  LONG lPageCount;
} WIA_DATA_CALLBACK_HEADER, *PWIA_DATA_CALLBACK_HEADER;

Members

lSize

Type: LONG

Must contain the size of this structure in bytes. Should be initialized to sizeof(WIA_DATA_CALLBACK_HEADER).

guidFormatID

Type: GUID

Indicates the image clipboard format. For a list of clipboard formats, see SetClipboardData Function. This parameter is queried during a callback to the IWiaDataCallback::BandedDataCallback method with the lMessage parameter set to IT_MSG_DATA_HEADER.

lBufferSize

Type: LONG

Specifies the size in bytes of the buffer needed for a complete data transfer. This value can be zero, which indicates that the total image size is unknown. (when using compressed data formats, for example). In this case, the application should dynamically increase the size of its buffer. For more information, see Common WIA Item Property Constants in WIA_IPA_ITEM_SIZE.

lPageCount

Type: LONG

Specifies the page count. Indicates the number of callbacks to the IWiaDataCallback::BandedDataCallback method with the lMessage parameter set to IT_MSG_NEW_PAGE.

Requirements