L_TwainAcquireMulti

#include "lttwn.h"

L_LTTWN_API L_INT L_TwainAcquireMulti(hSession, pszBaseFileName, uFlags, uTransferMode, nFormat, nBitsPerPixel, bMultiPageFile, uUserBufSize, bUsePrefferedBuffer, pfnCallBack, pUserData)

HTWAINSESSION hSession;

handle to an existing TWAIN session

L_TCHAR *pszBaseFileName;

base string

L_UINT uFlags;

option flags

L_UINT uTransferMode;

transfer mode

L_INT nFormat;

output file format

L_INT nBitsPerPixel;

resulting files pixel depth

L_BOOL bMultiPageFile;

naming flag

L_UINT32 uUserBufSize;

user-defined buffer size

L_BOOL bUsePrefferedBuffer;

buffer size flag

LTWAINACQUIRECALLBACK pfnCallBack;

optional callback function

L_VOID * pUserData;

pointer to more parameters for the callback

Acquires one or more images from a TWAIN source and stores the images in the specified file(s).

Parameter Description
hSession Handle to an existing TWAIN session. This handle is obtained by calling the L_TwainInitSession or L_TwainInitSession2 function.
pszBaseFileName Character string containing the base name of the image file(s) in which to save the acquired data.
uFlags Flag that determines certain actions of the TWAIN source. Possible values are:
  Value Meaning
  LTWAIN_SHOW_USER_INTERFACE [0x0001] Shows the manufacturer's user interface as modeless.
  LTWAIN_MODAL_USER_INTERFACE [0x0002] Shows the manufacturer's user interface as a modal dialog. Works only if the LTWAIN_SHOW_USER_INTERFACE flag is set.
  LTWAIN_KEEPOPEN [0x0020] Keep the TWAIN data source open after scanning.
uTransferMode Flag that indicates the transfer mode to use when acquiring the image(s). Possible values are:
  Value Meaning
  LTWAIN_FILE_MODE [0x001] Use the File transfer mode
  LTWAIN_BUFFER_MODE [0x002] Use the Memory transfer mode
  LTWAIN_NATIVE_MODE [0x004] Use the Native transfer mode
nFormat Output file format. For valid values, refer to Formats of Output Files.
nBitsPerPixel Resulting file's pixel depth. Note that not all bits per pixel are available to all file formats. For valid values, refer to Formats of Output Files. If nBitsPerPixel is 0, the file will be stored using the closest BitsPerPixel value supported by that format.
bMultiPageFile Flag that indicates whether to save multiple images into a single multi-page file, or into a series of single page files. Possible values are:
  Value Meaning
  TRUE The scanned images will be saved in one multi-page file.
  FALSE Each scanned image will be saved in a separate file.
  Notice that it the format doesn't support multi-page files, then each scanned page will be saved in a separate file.
uUserBufSize Specifies a user-defined buffer size. This value will be used if uTransferMode is LTWAIN_BUFFER_MODE and the bUsePrefferedBuffer parameter is FALSE. This value must be a multiple of 16.
bUsePrefferedBuffer Flag that indicates whether to use the user-defined buffer size or the Twain driver preferred buffer size. Possible values are:
  Value Meaning
  TRUE Use the Twain driver preferred buffer size.
  FALSE Use the user-defined buffer size in the uUserBufSize parameter.
pfnCallBack Optional callback function, called twice for each page scan. The 1st call is to notify the page is start scanning, and the 2nd call is to notify the page scanning is finished. 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 the LTWAINACQUIRECALLBACK 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.

Returns

SUCCESS

The function was successful.

! = SUCCESS

An error occurred. Refer to Return Codes.

Comments

This function will acquire one or more images from a TWAIN source and store the images to the specified file(s).

Based on the scanner type, this function will determine the best/fastest scanning method to use. This method will be used when actually scanning the image(s). Before calling this function you can call L_TwainFindFastConfig to determine the best scan configuration and then pass the scan configuration information to the L_TwainAcquireMulti function. If you do not call L_TwainFindFastConfig before calling L_TwainAcquireMulti, then the L_TwainAcquireMulti function will determine the best scanning method.

If the file format specified in nFormat does not support multi-page files, this function will ignore the bMultiPageFile parameter and automatically save the scanned images in separate files. The naming of the files will be carried out as follows: if the string in pszBaseFileName is "Temp.jpg", the method will append the number of the image, 0001, 0002, etc, to the name of the file. Therefore, the output file names will be "Temp0001.jpg", "Temp0002.jpg", etc.

If the file format specified in nFormat supports multi-page files, this function will use the bMultiPageFile parameter to determine how to save multiple images. If bMultiPageFile is FALSE, each scanned page will be saved to a separate file, named in the same manner described in the paragraph above. If bMultiPageFile is TRUE, the name of the output file will be exactly the string in pszBaseFileName (Temp.jpg) and it will be saved as a multi-page file.

If uTransferMode is LTWAIN_BUFFER_MODE, and bUsePrefferedBuffer  is FALSE, then the function will use the user-defined buffer size in uUserBufSize. If however bUsePrefferedBuffer is TRUE, then the function will use the Twain driver preferred buffer size and will ignore uUserBufSize.

To cancel the acquire operation call the L_TwainCancelAcquire.

To stop acquire images only from the feeder of the TWAIN source, call the L_TwainStopFeeder function.

The LTWAIN_KEEPOPEN flag works only in the following cases:

1.

Passed with LTWAIN_SHOW_USER_INTERFACE flag to make the TWAIN user-interface appears as a modeless dialog. The TWAIN data source remains open after scanning until the user closes it.

2.

Passed with LTWAIN_SHOW_USER_INTERFACE and LTWAIN_MODAL_USER_INTERFACE flags to make the TWAIN user-interface appears as a modal dialog. The TWAIN data source remains open after scanning until the user closes it.

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_TwainAcquireList, L_TwainInitSession, L_TwainEndSession, L_TwainOpenTemplateFile, L_TwainCloseTemplateFile, L_TwainTemplateDlg, L_TwainAddCapabilityToFile, L_TwainGetNumofCapsInFile, L_TwainGetCapabilityFromFile, L_TwainFindFastConfig, L_TwainGetScanConfigs, L_TwainFreeScanConfig, L_TwainCancelAcquire, L_TwainStopFeeder, L_TwainFastAcquire

Topics:

How to Acquire from the TWAIN Source

 

TWAIN Functionality: Property Functions.

Example

For complete sample, refer to FASTTWN demo.

#define MAKE_IMAGE_PATH(pFileName) TEXT("C:\\Users\\Public\\Documents\\LEADTOOLS Images\\")pFileName 
L_VOID EXT_CALLBACK AcquireMultiCB(HTWAINSESSION hSession, 
L_INT         nPage, 
L_TCHAR*      pszFileName, 
L_BOOL        bFinishScan, 
L_VOID*       pUserData) 
{ 
   UNREFERENCED_PARAMETER(hSession); 
   UNREFERENCED_PARAMETER(pUserData); 
   L_TCHAR szTemp[MAX_PATH]; 
   if (bFinishScan) 
   { 
      wsprintf(szTemp, TEXT("The page # %d is scanned and saved to file name %s\n"), nPage, pszFileName); 
      MessageBox(NULL, szTemp, TEXT("Notice"), MB_OK); 
   } 
} 
L_LTTWNTEX_API  L_INT TwainAcquireMultiExample(HWND hWnd,HTWAINSESSION hSession) 
{ 
   L_INT nRet; 
   nRet = L_TwainAcquireMulti(hSession, 
   MAKE_IMAGE_PATH(TEXT("test.tif")), 
   LTWAIN_SHOW_USER_INTERFACE, 
   LTWAIN_BUFFER_MODE, 
   FILE_TIF, 
   1, 
   TRUE, 
   0, 
   FALSE, 
   AcquireMultiCB, NULL); 
   if (nRet == SUCCESS) 
      MessageBox(hWnd, TEXT("Fast Twain function was successful"), TEXT("Notice"), MB_OK); 
   else 
      MessageBox(hWnd, TEXT("Error occurred during fast Twain function!!!"), TEXT("Error!!!"), MB_OK); 
   return nRet; 
} 

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