Twain Feeder : Tutorial # 1

Note: The purpose of this TWAIN tutorial is to provide you a quick and easy way to generate a TWAIN program. For more in depth TWAIN programming, refer to the TWAIN demo.

To create and run a program that implements LEADTOOLS TWAIN Feeder features:

1.	Create a new directory in the \Examples\API directory called TwainFeeder1
2.	Copy everything in the SimpleLoad directory into the TwainFeeder1 directory.
3.	Compile the project as it is and run SimpleLoad.exe to familiarize yourself with the basic program.
4.	In the Imports.cpp, add the following lines:

#if defined(WIN64)

…

#else

…

#pragma comment(lib, "..\\..\\..\\Lib\\API\\Win32\\Lttwn_u.lib")

#endif // #if defined(WIN64)

5.	Add the following line in StdAfx.h in the TwainFeeder1 directory:

#include "..\..\..\include\lttwn.h"

6.	Define the following global variables in Ezfunc.h in the TwainFeeder1 directory:

HTWAINSESSION hSession;

Also, add the following defines:

#define IDM_ACQUIRE 200

7.	Edit EZFUNC.RC file in the TwainFeeder1 directory and add the following lines:

#include "EZFUNC.H"

MAIN_MENU MENU

BEGIN

MENUITEM "Acquire" IDM_ACQUIRE

END

8.	In the InitApplication function change the line:

wcWindowClass.lpszMenuName = NULL; /* No menu */
to be
wcWindowClass.lpszMenuName = TEXT("MAIN_MENU");

9.	In the MainWndProc function and before the handling of the WM_PALETTECHANGED message add the following code:

   case WM_COMMAND:
      {
         switch (LOWORD(wParam))
         {
         case IDM_ACQUIRE:
            {
            }
            break;
         }
      }
      break;

10.	In the IDM_ACQUIRE menu handler add the following code:

         case IDM_ACQUIRE:
            {
               TwainTestFeeder1(hWnd);
            }

11.	Add the following function to the EZFUNC.CPP:

L_INT EXT_CALLBACK TwainAcquireCB(HTWAINSESSION hSession, pBITMAPHANDLE pBitmap, L_VOID * pUserData)

{

UNREFERENCED_PARAMETER(hSession);

UNREFERENCED_PARAMETER(pBitmap);

UNREFERENCED_PARAMETER(pUserData);

if (LeadBitmap.Flags.Allocated)

L_FreeBitmap(&LeadBitmap);

L_CopyBitmap(&LeadBitmap, pBitmap, sizeof(BITMAPHANDLE));

L_FreeBitmap(pBitmap);

return SUCCESS;

}

12.	Add the following function to the EZFUNC.CPP after TwainAcquireCB:

void TwainTestFeeder1(HWND hWnd)
{
   HTWAINSESSION hSession;
   APPLICATIONDATA AppData;
   TW_CAPABILITY twCap;
   L_INT nRet;
   L_BOOL bEnable;

   memset(&AppData, 0, sizeof(APPLICATIONDATA));

   AppData.hWnd = hWnd;
   lstrcpy (AppData.szManufacturerName, TEXT("LEAD Technologies, Inc."));
   lstrcpy (AppData.szAppProductFamily, TEXT("LEAD Sample"));
   lstrcpy (AppData.szVersionInfo,      TEXT("Version 1.0"));
   lstrcpy (AppData.szAppName,          TEXT("LEAD Sample"));
   AppData.uStructSize = sizeof(APPLICATIONDATA);

   nRet = L_TwainInitSession(&hSession, &AppData);
   if (nRet != TWAIN_SUCCESS)
      return;

   L_TwainSelectSource(hSession, NULL);
   L_TwainStartCapsNeg(hSession);

   twCap.Cap = CAP_AUTOFEED;
   twCap.ConType = TWON_ONEVALUE;
   twCap.hContainer = GlobalAlloc(GHND, sizeof(TW_ONEVALUE));

   pTW_ONEVALUE pOneValue = (pTW_ONEVALUE)GlobalLock(twCap.hContainer);
   bEnable = TRUE;

   pOneValue->ItemType = TWTY_BOOL;
   pOneValue->Item = (TW_UINT32)bEnable;

   GlobalUnlock(twCap.hContainer);

   nRet = L_TwainSetCapability(hSession, &twCap, LTWAIN_CAPABILITY_SET);
   if (nRet == TWAIN_SUCCESS)
      MessageBox(hWnd, TEXT("AutoFeed capability is enabled"), TEXT("Notice"), MB_OK);
   else
      MessageBox(hWnd, TEXT("Can't enable AutoFeed capability"), TEXT("Notice"), MB_OK);

   L_TwainEndCapsNeg(hSession);

   // try to acquire pages using AutoFeed capability
   L_TwainAcquire(hSession, NULL, sizeof(BITMAPHANDLE), TwainAcquireCB, LTWAIN_SHOW_USER_INTERFACE | LTWAIN_MODAL_USER_INTERFACE, NULL, NULL);

   L_TwainEndSession(&hSession);
}

13.	Compile and test the program.