LWia::AcquireSimple

Summary

Acquires one or more images from a WIA source.

Syntax

virtual L_INT LWia::AcquireSimple(uWiaVersion, uDeviceType, uFlags, pSourceItem, pAcquireOptions, pnFilesCount, pppszFilePaths)

Parameters

L_UINT uWiaVersion

The WIA version to be used. Possible values are:

L_UINT32 uDeviceType

Specifies which type of WIA device to use. Possible values are:

L_UINT32 uFlags

Flag that determines certain actions of the WIA image acquisition selection dialog box and device selection dialog. Combine values when appropriate by using a bitwise OR ( | ). Possible values are:

L_VOID * pSourceItem

Specifies the scanner's paper source (Feeder or Flatbed). Used only when acquiring from a scanner device and while the L_WIA_SHOW_USER_INTERFACE flag is NOT set.

This flag is optional if you are using WIA 1.0, because you can change the paper source by changing the WIA_DPS_DOCUMENT_HANDLING_SELECT property for the root item, or by enumerating the available scanner items and passing the item you wish to scan from.

If you are using WIA 2.0, then you have to enumerate the available scanner items and pass the item you wish to scan from. Or you can pass NULL, in which case the enumeration will be done internally and the first enumerated item will be used as the source item.

pLWIAACQUIREOPTIONS pAcquireOptions

Pointer to an optional Acquire Options structure containing information for controlling the acquisition behavior from the WIA device.

Pass NULL to use the internal default values.

L_INT * pnFilesCount

Pointer to a variable of type L_INT to be updated with the number of the files to be saved when acquiring using File mode.

L_TCHAR *** pppszFilePaths

Pointer to a string buffer to hold an array of the saved file paths. Used when the transfer mode is file.

You can define a variable of type L_TCHAR*** of size zero and pass the address of that variable to the acquire function.

It is the user's responsibility to free the received file name array.

Returns

Comments

This feature is available in LEADTOOLS version 16 or higher.

This is a high level acquire function that you can call directly. When using this function, the following functions are called internally:

LWia::InitSession

LWia::SelectDeviceDlg

LWia::EndSession

Specify the parent window for the image acquisition dialog by calling the LScanner::SetWindow function.

Set [LWia:AcquireSimple for memory transfer or file transfer as follows:

• Designate the transfer mode to be used with the LWIAPROPERTIES structure and pass it to the LWia::SetProperties method.

• Call the low level LWia::SetPropertyLong, passing WIA_IPA_TYMED for the uID member of this method and the transfer mode to be used (TYMED_CALLBACK or TYMED_FILE) for the lValue member.

When performing memory transfer, override the LWia::AcquireCallBack function in order to receive the acquired page(s) through the pBitmap parameter of this callback. The callback also provides the percent completion of the page transfer progress.

When performing file transfer, overriding the LWia::AcquireCallBack function is optional: the callback only provides the saved file path and the percent completion of the file save process.

To cancel the acquire operation, override the LWia::AcquireCallBack function and return the ERROR_USER_ABORT error code.

L_WIA_SHOW_USER_INTERFACE Note

Microsoft's image acquisition dialog box sets its own initialization properties, such as the current intent (image type), selected area (left, top, width and height), paper source, duplex mode, etc.

If the L_WIA_SHOW_USER_INTERFACE flag is set, Microsoft's image acquisition dialog box overwrites some properties set/changed by any of the LWia::SetPropertyXXX or LWia::SetProperties functions.

To prevent overwriting, do not set the L_WIA_SHOW_USER_INTERFACE flag if any LWia::SetPropertyXXX or LWia::SetProperties functions need to be called.

Microsoft WIA Toolkit Limitation

The Microsoft WIA Toolkit has the following, known limitation:

A Win32 version application running on Windows VISTA 64-bit that calls LWia::Acquire, specifying the pnFilesCount and pppszFilePaths parameters, fails to fill those two members with the required information.

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.

See Also

Functions

• LWia::Acquire
• LWia::AcquireToFile
• Class Members

Topics

• How to Acquire from the WIA Source
• WIA Functionality: Property Functions

Example

class CMyWIA : public LWia 
{ 
public: 
   L_INT AcquireSimpleCallBack(pBITMAPHANDLE pBitmap, L_TCHAR * pszFilename, L_UINT32 uPercent, L_UINT32 uFlags); 
}; 
 
L_INT CMyWIA::AcquireSimpleCallBack(pBITMAPHANDLE pBitmap, L_TCHAR * pszFilename, L_UINT32 uPercent, L_UINT32 uFlags) 
{ 
   UNREFERENCED_PARAMETER(pBitmap); 
   UNREFERENCED_PARAMETER(pszFilename); 
   UNREFERENCED_PARAMETER(uPercent); 
   UNREFERENCED_PARAMETER(uFlags); 
 
   // You can do here any processing to the bitmap 
 
   return WIA_SUCCESS; 
} 
 
L_INT LWIA__AcquireSimpleExample(L_UINT uWiaVersion) 
{ 
   L_INT nRet; 
   LWIAACQUIREOPTIONS AcquireOpts; 
   L_UINT uFlags; 
   CMyWIA MyClass; 
 
   uFlags = L_WIA_SELECT_DEVICE_NODEFAULT | L_WIA_DEVICE_DIALOG_USE_COMMON_UI; 
 
   /* Initialize and fill the required fields from the LWIAACQUIREOPTIONS structure */ 
   memset(&AcquireOpts, 0, sizeof(LWIAACQUIREOPTIONS)); 
   AcquireOpts.uStructSize = sizeof(LWIAACQUIREOPTIONS); 
   AcquireOpts.bDoubleBuffer = TRUE; 
   AcquireOpts.uMemBufSize = 64 * 1024; 
 
   nRet = MyClass.AcquireSimple(uWiaVersion,  
                                WiaDeviceTypeDefault,  
                                uFlags,  
                                &AcquireOpts,  
                                NULL, 
                                NULL, 
                                NULL); 
   if(nRet != WIA_SUCCESS) 
      return nRet; 
 
   return SUCCESS; 
}