LTWAINBITMAPCALLBACK Function

#include "lttwn.h"

L_INT pEXT_CALLBACK YourFunction (hSession, pBitmap, pUserData)

HTWAINSESSION hSession;	/* handle to an existing TWAIN session */
pBITMAPHANDLE * pBitmap;	/* pointer to the bitmap handle */
L_VOID * pUserData;	/* pointer to additional parameters */

Called for each image being acquired from the TWAIN source to the application. The address of this callback is passed as an argument in L_TwainAcquire.

Parameter	Description
hSession	Handle to an existing TWAIN session. This handle is obtained by calling the L_TwainInitSession function.
pBitmap	Pointer to the bitmap handle that references the bitmap acquired from the TWAIN source. It is the same bitmap handle that you specify when calling the L_TwainAcquire function.
pUserData	A void pointer that you can use to access a variable or structure containing data that your callback function needs. This gives you a way to receive data indirectly from the function that uses this callback function. (This is the same pointer that you pass in the pUserData parameter of L_TwainAcquire.)
	Keep in mind that this is a void pointer, which must be cast to the appropriate data type within your callback function.

Returns

SUCCESS	The function was successful.
< 1	An error occurred. Refer to Return Codes.

Comments

To prevent memory leaks, the user should free the bitmap within the callback function.

The L_TwainGetExtendedImageInfo function can only be called within the callback.

Required DLLs and Libraries

LTTWN

For a listing of the exact DLLs and Libraries needed, based on the toolkit version, refer to Files To Be Included With Your Application.

Functions:	L_TwainAcquire, L_TwainGetExtendedImageInfo
Topics:	TWAIN Functionality: Callback Functions.