LWIAACQUIREFILECALLBACK

#include "ltwia.h"

L_INT pEXT_CALLBACK YourFunction(hSession, pszFilename, uPercent, uFlags, pUserData)

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

Parameters

HWIASESSION hSession

Handle to an existing WIA session. This handle is obtained by calling the L_WiaInitSession function.

L_TCHAR * pszFilename

Character string containing the name of the file to which to save the scanned image(s).

L_UINT32 uPercent

The percent completion of the page being scanned.

L_UINT32 uFlags

Flag that indicates the start or the end of the scanned page. Possible values are:

Value	Meaning
0	Default value when this is not the first transferred chunk or the last transferred chunk.
L_WIA_ACQUIRE_START_OF_PAGE	[0x00000001] Indicates the start of the page being scanned.
L_WIA_ACQUIRE_END_OF_PAGE	[0x00000002] Indicates the end of the page being scanned. Use this value to reset the progress bar.

L_VOID * 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_WiaAcquire or L_WiaAcquireSimple.)

Keep in mind that this is a void pointer, which must be cast to the appropriate data type within your callback function.

Returns

Value	Meaning
SUCCESS	The function was successful.
ERROR_USER_ABORT	The callback wants to abort the scanning operation.
< 1	An error occurred. Refer to Return Codes.

Comments

This feature is available in version 16 or higher.

Called many times to provide the user with a status update of the acquire progress, in percent. It is also called when the page ends to pass you the L_WIA_ACQUIRE_END_OF_PAGE flag in the uFlags parameter.

✎ NOTE

If you are using WIA 2.0 while the L_WIA_SHOW_USER_INTERFACE is set then no need to provide a callback pointer since Microsofts WIA 2.0 acquire dialog does not provide a callback and it does all the process and return back to you with the saved files count and paths.

Required DLLs and Libraries

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