Set/Get a Twain Capability

Take the following steps to get or set a twain capability:

1. Start Microsoft Visual Studio.
2. Select the File->New menu option and then 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 TwainTutor3.
5. In the Location dialog box, use the "Examples\Scanning\ClassLibrary" directory of your LEAD installation. For example, if you installed LEADTOOLS in *C:\LEADTOOLS23*, enter C:\LEADTOOLS23\Examples\Scanning\ClassLibrary, then click OK. Then click Next.
6. Choose Dialog based and click Finish.
7. Click the Solution Explorer tab, and then click the TwainTutor3 project to expand it. Click the Header files, then Open TwainTutor3.h.

8. Add the following line immediately before the class CTwainTutor3App declaration (keep in mind, you may have to change the path to where the header files reside):

   #include "..\..\..\..\include\ClassLib\ltwrappr.h" 

9. Click the Class View tab.

10. Click to open the TwainTutor3 classes branch.
11. Click CTwainTutor3App, and then double-click the CTwainTutor3App(void) constructor.

12. Add the following lines after //TODO: add construction code here:

    LBase::LoadLibraries(LT_ALL_LEADLIB);   
    L_TCHAR * pszLicenseFile = L"Replace this with the path to the LEADTOOLS license file";   
    L_TCHAR * pszDeveloperKey = L"Replace this with your developer key";   
    LSettings::SetLicenseFile(pszLicenseFile, pszDeveloperKey);   

13. Create a new file called Imports.cpp and place it beside your project files.

    1. In the Project Workspace, click the Solution Explorer tab.
    2. Double-click the TwainTutor3 folder to open it.
    3. Right-click the source files folder and select Add New item.
    4. Expand the Visual C++ tree, if it is not already expanded.
    5. Select Code from the sub-tree.
    6. Select C++ File (.cpp) from the right window.
    7. In the name text box, specify Imports.cpp.
    8. Click the Add button.
    9. 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\\CDLL\\Win32\\Ltwvc_u.lib")   
       #endif // #if defined(WIN64)  

14. Click the Solution Explorer tab.

15. Double-click the TwainTutor3 folder to open it.
16. Double-click the Header Files folder to open it. Then double click TwainTutor3Dlg.h file to open it.

17. Add the following class declaration before the CTwainTutor3Dlg class.

    class LMyTwain : public LTwain 
    { 
       LEAD_DECLAREOBJECT(LMyTwain); 
    public: 
       LMyTwain(); 
       virtual ~LMyTwain(); 
       virtual L_INT BitmapCallBack(pBITMAPHANDLE pBitmap); 
    }; 

18. Click the Solution Explorer tab.

19. Double-click the TwainTutor3 folder to open it.
20. Double-click the Source Files folder to open it. Then double-click the TwainTutor3Dlg.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 the Class View tab.

23. Right-click CTwainTutor3Dlg and select Add Add Variable....
24. For Variable Type enter LMyTwain, and for Variable Declaration put m_MyTwain. Leave Access as Public and click OK.
25. Right-click CTwainTutor3Dlg and select Add Add Variable....
26. For Variable Type enter TW_CAPABILITY, and for Variable Declaration put m_twCap. Leave Access as Public and click OK.
27. Right-click CTwainTutor3Dlg and select Add Add Variable....
28. For Variable Type enter L_UINT, and for Variable Declaration put m_uItemValue. Leave Access as Public and click OK.
29. Click to open the CTwainTutor3Dlg branch. Double-click the OnInitDialog() function and add the following code after the 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);  

1. Right-click the CTwainTutor3Dlg branch, and choose Properties.
2. From the Properties window toolbar, click the Messages icon. Then click the empty area beside the item WM_DESTROY and choose OnDestroy.

3. Add the following code after the opening bracket {:

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

4. Click the Solution Explorer tab.

5. Double-click the TwainTutor3 folder to open it.
6. Double-click the Resource Files folder to open it. Then double-click "TwainTutor3.rc" file to open it, then double-click "Dialog", and then double-click IDD_TWAINTUTOR3_DIALOG.

7. Now drag and drop 5 buttons, and change their properties as follows:

   Control Type	ID	Caption
   Button1	IDC_SELECT_SRC	Select Source
   Button2	IDC_ACQUIRE	Acquire
   Button3	IDC_GET_CAPABILITY	Get Capability
   Button4	IDC_SET_CAPABILITY	Set Capability
   Button5	IDC_SET_BRIGHTNESS	Set Brightness

8. From the View menu, select the Other Windows menu, then select the Resource View menu, then select Dialog, and select IDD_TWAINTUTOR3_DIALOG.

9. Double-click the Select Source button, and add the following code:

      m_MyTwain.SelectSource(NULL);  

10. From the View menu, select the Other Windows menu, then select the Resource View menu, then select Dialog, and select IDD_TWAINTUTOR3_DIALOG

11. Double-click the Acquire button, and add the following code:

       BITMAPHANDLE Bitamp;    
       m_MyTwain.Acquire(&Bitamp, sizeof(BITMAPHANDLE), LTWAIN_SHOW_USER_INTERFACE, NULL);  

12. From the View menu, select the Other Windows menu, then select the Resource View menu, then select Dialog, and select IDD_TWAINTUTOR3_DIALOG.

13. Double-click the Get Capability button, and add the following code:

       L_INT  nItemType;    
       m_twCap.Cap = ICAP_XFERMECH;    
       m_twCap.ConType = TWON_DONTCARE16;    
       m_twCap.hContainer = NULL;    
       m_MyTwain.GetCapability(&m_twCap, LTWAIN_CAPABILITY_GETCURRENT);    
       m_MyTwain.GetNumericContainerItemType(&m_twCap, &nItemType);    
       if (nItemType == TWTY_UINT16)    
          m_MyTwain.GetNumericContainerUINTValue(&m_twCap, 0, &m_uItemValue);    
       else   
          AfxMessageBox(TEXT("Returned bad item type")); 

14. From the View menu, select the Other Windows menu, then select the Resource View menu, then select Dialog, and select IDD_TWAINTUTOR3_DIALOG.

15. Double-click the Set Capability button, and add the following code:

    if (m_uItemValue != TWSX_NATIVE) 
    { 
       TW_CAPABILITY twSetCap; 
       twSetCap.Cap = ICAP_XFERMECH; 
       twSetCap.ConType = TWON_ONEVALUE; 
       m_MyTwain.CreateNumericContainerOneValue(&twSetCap, TWAINNUMERICTYPE_TW_UINT16, TWSX_NATIVE); 
       m_MyTwain.SetCapability(&twSetCap, LTWAIN_CAPABILITY_SET); 
       m_MyTwain.FreeContainer(&twSetCap); 
    } 
    else 
       AfxMessageBox(TEXT("The Transfer mode is Native")); 

16. From the View menu, select the Other Windows menu, then select the Resource View menu, then select Dialog, and select IDD_TWAINTUTOR3_DIALOG.

17. Double-click the Set Brightness button, and add the following code:

    TW_CAPABILITY twBrightnessCap; 
    TW_FIX32      twFix32; 
    pTW_ONEVALUE  ptwOneVal; 
    twBrightnessCap.Cap = ICAP_BRIGHTNESS; 
    twBrightnessCap.ConType = TWON_ONEVALUE; 
    L_INT nRet = m_MyTwain.GetCapability(&twBrightnessCap, LTWAIN_CAPABILITY_GETCURRENT); 
    if (nRet == SUCCESS) 
    { 
       ptwOneVal = (pTW_ONEVALUE)GlobalLock(m_twCap.hContainer); 
       memcpy(&twFix32, (void *)&ptwOneVal->Item, sizeof(TW_FIX32)); 
       GlobalUnlock(twBrightnessCap.hContainer); 
       GlobalFree(twBrightnessCap.hContainer); 
       twBrightnessCap.hContainer = NULL; 
       if (twFix32.Whole != 128) 
       { 
          twFix32.Whole = 128; 
          twFix32.Frac = 0; 
       } 
       twBrightnessCap.Cap = ICAP_BRIGHTNESS; 
       twBrightnessCap.ConType = TWON_ONEVALUE; 
       twBrightnessCap.hContainer = GlobalAlloc(GHND, sizeof(TW_ONEVALUE) + sizeof(TW_FIX32)); 
       ptwOneVal = (pTW_ONEVALUE)GlobalLock(m_twCap.hContainer); 
       ptwOneVal->ItemType = TWTY_FIX32; 
       memcpy((void *)&ptwOneVal->Item, &twFix32, sizeof(TW_FIX32)); 
       GlobalUnlock(twBrightnessCap.hContainer); 
       m_MyTwain.SetCapability(&twBrightnessCap, LTWAIN_CAPABILITY_SET); 
    } 

18. Compile and test the program.