Set up a TWAIN Duplex (Dual Page) Scan

Twain Duplex Tutorial

Take the following steps to create and run a program that implement LEADTOOLS TWAIN features. Remember, the purpose of the TWAIN tutorial is to provide you a quick and easy way to generate a TWAIN program.

1.	Start Microsoft Visual Studio 2005
2.	Select the File->New menu option, click the "Project" menu.
3.	From "Project Types" select "Other Languages" to expand it, then select "Visual C++" to expand it, then select "MFC". From the right window select "MFC Application".
4.	In the Project Name dialog box, enter "TwainDuplex".
5.	In the Location dialog box, use the "Examples\ClassLibrary\MSVC" directory of your LEAD installation. For example, if you installed LEADTOOLS in "C:\Program Files\LEAD Technologies\LEADTOOLS 15\", enter "C:\Program Files\LEAD Technologies\LEADTOOLS 15\ Examples\ClassLibrary\MSVC", then Click OK. Then click "Next".
6.	Choose "Dialog based" and click "Finish".
7.	Click on the "Solution Explorer" tab, and then click on the "TwainDuplex" project to expand it. Click on the Header files, then Open "TwainDuplex.h".
8.	Add the following line immediately before the class CTwainDuplexApp declaration, (keep in mind, you may have to change the path to where the header files reside):
	#include "..\..\..\..\include\ClassLib\ltwrappr.h"
9.	Click on the "Class View" tab.
10.	Click to open the "TwainDuplex" classes branch.
11.	Click "CTwainDuplexApp", and then double click the CTwainDuplexApp(void) constructor.
12.	Add the following lines after //TODO: add construction code here:

LBase::LoadLibraries(LT_ALL_LEADLIB);
LSettings::UnlockSupport(L_SUPPORT_DOCUMENT, L_KEY_DOCUMENT);

13.	Create a new file called Imports.cpp in place it beside your project files.
	a.	In the Project Workspace, click the Solution Explorer tab.
	b.	Double-click the TwainDuplex folder to open it.
	c.	Right-click the Source files folder and select Add à New item.
	d.	Expand Visual C++ tree, if it is not already expanded.
	e.	Select Code from the sub tree.
	f.	Select C++ File (.cpp) from the right window.
	g.	In the name text box, specify Imports.cpp
	h.	Click the Add button.
	i.	Double-click the imports.cpp in the solution Explorer and add the following lines:

#include "StdAfx.h"

#if defined(WIN64)

#else
#pragma comment(lib, "..\\..\\..\\..\\Lib\\API\\Win32\\Ltwvc_u.lib")
#endif // #if defined(WIN64)

14.	Click on the "Solution Explorer" tab.
15.	Double-click the "TwainDuplex" folder to open it.
16.	Double-click the "Header Files" folder to open it. Then double click "TwainDuplexDlg.h" file to open it.
17.	Add the following class declaration before CTwainDuplexDlg class.

class LMyTwain : public LTwain
{
   LEAD_DECLAREOBJECT(LMyTwain);

public:
   LMyTwain();
   virtual ~LMyTwain();
   virtual L_INT BitmapCallBack(pBITMAPHANDLE pBitmap);
};

18.	Click on the "Solution Explorer" tab.
19.	Double-click the "TwainDuplex" folder to open it.
20.	Double-click the "Source Files" folder to open it. Then double click "TwainDuplexDlg.cpp" file to open it.
21.	Add the following class:

LEAD_IMPLEMENTOBJECT(LMyTwain);
LMyTwain::LMyTwain()
{
   EnableCallBack(TRUE);
}

LMyTwain::~LMyTwain()
{
}

L_INT LMyTwain::BitmapCallBack(pBITMAPHANDLE pBitmap)
{
   //Copy the acquired bitmap here
   return SUCCESS;
}

22.	Click on the "Class View" tab.
23.	Right click "CTwainDuplexDlg" and select Add à "Add Variable..."
24.	For Variable Type enter LMyTwain, and for Variable Declaration put m_MyTwain. Leave Access as "Public" and click OK.
25.	Click to open the CTwainDuplexDlg branch. Double click the OnInitDialog() function and add the following code after line:
	// TODO: Add extra initialization here

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

   AppData.hWnd = m_hWnd;
   AppData.uStructSize = sizeof(AppData);
   lstrcpy(AppData.szManufacturerName, _T("LEAD Technologies, Inc."));
   lstrcpy(AppData.szAppProductFamily, _T("LEAD Test Applications"));
   lstrcpy(AppData.szVersionInfo, _T("Version 1.0"));
   lstrcpy(AppData.szAppName, _T("TWAIN Test Application"));
   m_MyTwain.InitSession(&AppData);

26.	Right click the CTwainDuplexDlg branch, and choose "Properties".
27.	From the "Properties" window toolbar, click on the Messages icon. Then click on the empty area beside the item "WM_DESTROY" and choose OnDestroy.
28.	Add the following code after the opening bracket {:

m_MyTwain.EndSession();
LBase::UnloadLibraries(LT_ALL_LEADLIB);

29.	Click on the "Solution Explorer" tab.
30.	Double-click the "TwainDulpex" folder to open it.
31.	Double-click the "Resource Files" folder to open it. Then double click "TwainDuplex.rc" file to open it, then double click "Dialog", and then double click "IDD_TWAINDUPLEX_DIALOG"
32.	Now, drag and drop 1 button, and change their properties as follows:
	ID	Caption
	IDC_ACQUIRE	Acquire
33.	From View menu, select "Other Windows" menu, then select "Resource View" menu, then select Dialog, and select "IDD_TWAINTUTOR3_DIALOG"
34.	Double click on "Acquire" button, and add the following code:

   BITMAPHANDLE Bitmap;
   L_INT nRet;
   TW_CAPABILITY twCap;

   m_MyTwain.SelectSource(NULL);

   twCap.Cap = CAP_DUPLEX;
   twCap.ConType = TWON_ONEVALUE;
   twCap.hContainer = NULL;

   nRet = m_MyTwain.GetCapability(&twCap, LTWAIN_CAPABILITY_GETVALUES);
   if (nRet == TWAIN_SUCCESS)
   {
      // check if the selected driver supports duplex capability
      pTW_ONEVALUE pOneValue = (pTW_ONEVALUE)GlobalLock(twCap.hContainer);
      if (pOneValue->ItemType != TWTY_UINT16)
      {
         GlobalUnlock(twCap.hContainer);
         m_MyTwain.FreeContainer(&twCap);
         return;
      }

      TW_UINT16 item = (TW_UINT16)pOneValue->Item;

      switch (item)
      {
      case TWDX_NONE:
         AfxMessageBox(TEXT("Duplex capability is not supported in the selected driver"));
         break;
      case TWDX_1PASSDUPLEX:
         AfxMessageBox(TEXT("1 Pass Duplex capability is supported in the selected driver"));
         break;
      case TWDX_2PASSDUPLEX:
         AfxMessageBox(TEXT("2 Pass Duplex capability is supported in the selected driver"));
         break;
      }

      GlobalUnlock(twCap.hContainer);
      m_MyTwain.FreeContainer(&twCap);

      // make sure the duplex capability is enabled
      if (item != TWDX_NONE)
      {
         BOOL bEnable = TRUE;

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

         pTW_ONEVALUE pOneValue = (pTW_ONEVALUE)GlobalLock(twCap.hContainer);
         pOneValue->ItemType = TWTY_BOOL;
         pOneValue->Item = (TW_UINT32)bEnable;

         GlobalUnlock(twCap.hContainer);
         nRet = m_MyTwain.SetCapability(&twCap, LTWAIN_CAPABILITY_SET);
         if (nRet == TWAIN_SUCCESS)
            AfxMessageBox(TEXT("The duplex capability is enabled"));
         else
            AfxMessageBox(TEXT("Can't enable duplex capability"));
      }
   }
   else
      AfxMessageBox(TEXT("Duplex capability is not supported in the selected driver"));

   // try to acquire pages using duplex capability
   m_MyTwain.Acquire(&Bitmap, sizeof(BITMAPHANDLE), LTWAIN_SHOW_USER_INTERFACE | LTWAIN_MODAL_USER_INTERFACE, NULL);

35.	Compile and test the program.