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 or L_TwainInitSession2 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.

See Also

Functions:

L_TwainAcquire, L_TwainGetExtendedImageInfo

Topics:

TWAIN Functionality: Callback Functions.

Example

For an example, refer to L_TwainAcquire.

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