HWIASESSION hSession;

/* handle to an existing WIA session */

L_VOID* pItem;

/* pointer to IWiaItem or IWiaItem2 interface */

pLWIAPROPERTIES pProperties;

/* pointer to a structure */

LWIASETPROPERTIESCALLBACK pfnCallBack;

/* pointer to callback function */

L_VOID * pUserData;

/* pointer to additional parameters */

Parameter

Description

hSession

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

pItem

Valid pointer to a type IWiaItem or IWiaItem2 object (IWiaItem if using WIA Version 1.0; IWiaItem2 if using WIA Version 2.0), which represents the item that is having its properties set.

Retrieve this parameter by either calling the L_WiaGetRootItem function to get a pointer to the device's root item or by enumerating the child items of the device through a call to L_WiaEnumChildItems.

pProperties

Pointer to a structure of type LWIAPROPERTIES retrieved through the call to the L_WiaGetProperties function.

pfnCallBack

Optional callback function. It is called as each property is set. It lets the user know if an error occurred during the set operation and lets the user abort or retry by returning WIA_ABORT or WIA_RETRY.

If you do not provide a callback function, use NULL as the value of this parameter. No error reporting will occur.

If you do provide a callback function, use the function pointer as the value of this parameter.

The callback function must adhere to the function prototype described in LWIASETPROPERTIESCALLBACK function.

pUserData

Void pointer that you can use to pass one or more additional parameters that the callback function needs.

To use this feature, assign a value to a variable or create a structure that contains as many fields as you need. Then, in this parameter, pass the address of the variable or structure, casting it to L_VOID *. The callback function, which receives the address in its own pUserData parameter, can cast it to a pointer of the appropriate data type to access your variable or structure.

If the additional parameters are not needed, you can pass NULL in this parameter.

SUCCESS

The function was successful.

< 1

An error occurred. Refer to Return Codes.

Note:

If the user set the L_WIA_SHOW_USER_INTERFACE flag, then he should be aware of the following point:

Some of the these properties will be overwritten by the Microsoft image acquisition dialog box, like the current intent (image type), selected area (left, top, width and height), paper source and duplex mode, etc.

Note:

Through our test we have found the following limitation related to the Microsoft WIA toolkit: On some drivers, while using WIA 2.0, if you want to change the Image Data Type property (WIA_IPA_DATATYPE) to a custom setting then you have to set the WIA_IPS_CUR_INTENT property value to WIA_INTENT_NONE.

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.

Functions:

L_WiaGetProperties, L_WiaGetRootItem, L_WiaEnumChildItems, L_WiaInitSession, L_WiaEndSession, LWIASETPROPERTIESCALLBACK.

Topics:

Managing WIA Sources

WIA Functionality: Property Functions

WIA Functionality: Callbacks