Working with Pages Using LEADTOOLS OCR Module - LEAD Engine

To create and run a program that demonstrates how to add pages to an OCR document using Ltocr.h. This program will allow page insertion and to save the inserted page:

  1. Create a new directory in the \Examples\CDLL directory called OCR_Ltocr.
  2. Copy everything in the SimpleLoad directory (copy only folders content) into the OCR_Ltocr 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)    
       #pragma comment(lib, "..\\..\\..\\Lib\\CDLLVC10\\x64\\Ltocr_x.lib")   
    #else   
       #pragma comment(lib, "..\\..\\..\\Lib\\CDLLVC10\\Win32\\Ltocr_u.lib")   
    #endif // #if defined(WIN64) 

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

    /* LEADTOOLS main OCR document header file */   
    #include "..\..\..\include\ltocr.h"   
    #include "..\..\..\include\ltdlg.h" 

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

    #define IDM_INSERT_PAGE 200   
    #define IDM_SAVE_ADDED_PAGE 300   
    L_OcrEngine hEngine;                  /* OCR Engine handle */   
    L_OcrPage hPage;                      /* OCR Page handle */   
    L_OcrDocumentManager hDocumentManager; /* OCR Document Manager handle */   
    L_OcrDocument hDocument;              /* OCR Document handle */ 

  7. Add the following statements in Ezfunc.cpp in the WinMain function as follows:

    L_SetLicenseFile(TEXT("MyLicenseFile"), TEXT("DeveloperKey"));   
    L_INT nRet = L_OcrEngineManager_CreateEngine(L_OcrEngineType_LEAD, &hEngine);   
    if(nRet != SUCCESS)   
       return 0;   
    nRet = L_OcrEngine_Startup(hEngine, NULL, NULL);   
    if(nRet != SUCCESS)   
       return 0;   
    nRet = L_OcrEngine_GetDocumentManager(hEngine, &hDocumentManager);   
    if(nRet != SUCCESS)   
       return 0;   
    nRet = L_OcrDocumentManager_CreateDocument(hDocumentManager, &hDocument, L_OcrCreateDocumentOptions_AutoDeleteFile, NULL);   
    if(nRet != SUCCESS)   
       return 0; 

  8. Add the following after the GetMessage() loop before return statement:

    L_OcrDocument_Destroy(hDocument);   
    L_OcrEngine_Destroy(hEngine); 

  9. Edit EZFUNC.RC file in the OCR_Ltocr directory and add the following lines:

    #include "EZFUNC.H"   
    MAIN_MENU   MENU   
    BEGIN   
       MENUITEM "Insert Page"        IDM_INSERT_PAGE   
       MENUITEM "Save Added Page"    IDM_SAVE_ADDED_PAGE   
    END 

  10. In Ezfunc.cpp in InitApplication, change the line:

    wcWindowClass.lpszMenuName = NULL; 

    to:

    wcWindowClass.lpszMenuName = TEXT("MAIN_MENU"); 

  11. In Ezfunc.cpp in MainWndProc, change the line:

    Demos_CombinePath(szImagesDirectory, L_TEXT("Image1.cmp"), szFilename, _countof(szFilename));  

    To:

    Demos_CombinePath(szImagesDirectory, L_TEXT("ocr1.tif"), szFilename, _countof(szFilename)); 

  12. In Ezfunc.cpp in InitInstance, change the menu parameter (tagged as "Use the window class menu") in CreateWindow from NULL to:

    LoadMenu(hInstance, MAKEINTRESOURCE("MAIN_MENU")), /*Main Menu*/ 

  13. In Ezfunc.cpp after WM_PAINT and before WM_DESTROY, add a new switch statement called WM_COMMAND:

    /*After code below*/ 
    case WM_PAINT: 
    /* Get the handle to the device context */ 
    hdc = BeginPaint (hWnd, &ps); 
    if (LeadBitmap.Flags.Allocated)  /* Do we have an image? */ 
    { 
       if (hpalPaint) /* If we have a paint palette, select it */ 
       { 
          hPalette = SelectPalette (hdc, hpalPaint, TRUE); 
          /* Uncomment this if you do not process WM_QUERYNEWPALETTE */ 
          /* RealizePalette (hdc); */ 
       } 
       /* Paint the image */ 
       L_PaintDC (hdc, 
       &LeadBitmap, 
       &rLeadSource,   /* Source rectangle */ 
       NULL,           /* Default source clip area */ 
       &rLeadDest,     /* Destination rectangle */ 
       &ps.rcPaint,    /* Dest clip set by WM_PAINT */ 
       SRCCOPY);       /* Normal Paint */ 
       if (hpalPaint)         /* Return old palette */ 
          SelectPalette (hdc, hPalette, TRUE); 
    } 
    EndPaint (hWnd, &ps);     /* Return DC */ 
    return (0); 
    /*After code Above*/ 
    /* Add code below */ 
    case WM_COMMAND: 
    switch(LOWORD(wParam)) 
    { 
       case IDM_INSERT_PAGE: 
       { 
          // Create the OCR page from the loaded bitmap 
          nRet = L_OcrPage_FromBitmap(hEngine, &hPage, &LeadBitmap, L_OcrBitmapSharingMode_AutoFree, NULL, NULL); 
          if (nRet != SUCCESS) 
          { 
             MessageBox (NULL, TEXT("Error creating OCR page"), TEXT("Error"), MB_OK); 
             /* We have an error, so post WM_DESTROY */ 
             PostMessage (hWnd, WM_DESTROY, 0, 0); 
             return (FALSE); 
          } 
          // Add the created OCR page into the file-based OCR document 
          nRet = L_OcrDocument_AddPage(hDocument, hPage); 
          if (nRet != SUCCESS) 
          { 
             wsprintf (achBuff, TEXT("Error %d adding page at index 0"), nRet); 
             MessageBox (NULL, achBuff, TEXT("Error"), MB_OK); 
             /* We have an error, so post WM_DESTROY */ 
             PostMessage (hWnd, WM_DESTROY, 0, 0); 
             return (FALSE); 
          } 
          /* Force paint palette creation */ 
          SendMessage (hWnd, WM_QUERYNEWPALETTE, 0, 0L); 
          RedrawWindow(hWnd,0,0,256); 
          wsprintf (achBuff, TEXT("Page Width = %d\nPage Height = %d\nPage Bits Per Pixel = %d\n"), 
          LeadBitmap.Width, 
          LeadBitmap.Height, 
          LeadBitmap.BitsPerPixel); 
          MessageBox (NULL, achBuff, TEXT("Page Info"), MB_OK); 
       } 
       break; 
       case IDM_SAVE_ADDED_PAGE: 
       { 
          BITMAPHANDLE ExportBmp; 
          L_InitBitmap(&ExportBmp, sizeof(BITMAPHANDLE), 0, 0, 1); 
          nRet = L_OcrPage_GetBitmap(hPage, L_OcrPageBitmapType_Original, &ExportBmp, sizeof(BITMAPHANDLE)); 
          if (nRet != SUCCESS) 
          { 
             MessageBox(NULL, TEXT("Cannot retrieve page bitmap to save"), TEXT("Error!"), MB_OK); 
             return 0; 
          } 
          L_TCHAR szFileName[MAX_PATH] = {0}; 
          lstrcpy(szFileName, TEXT("c:\\test.tif")); 
          nRet = L_SaveBitmap(szFileName, ExportBmp, FILE_TIF, ExportBmp.BitsPerPixel, 0, NULL); 
          if(nRet != SUCCESS) 
          { 
             wsprintf (achBuff, TEXT("Error %d saving OCR page bitmap to %s"), nRet, szFileName); 
             MessageBox(NULL, achBuff, TEXT("Error!"), MB_OK); 
             return 0; 
          } 
          else 
          { 
             wsprintf (achBuff, TEXT("OCR page bitmap was saved to %s"), szFileName); 
             MessageBox(NULL, achBuff, TEXT("Error!"), MB_OK); 
             return 0; 
          } 
       } 
       break; 
    } 
    return 0; 
    /*Add code above*/ 

  14. Delete or comment out the following lines from WM_DESTROY message since L_OcrPage_Destroy call will free the bitmap since the OCR page owns the bitmap handle and you don't own it any more and this is because we passed L_OcrBitmapSharingMode_AutoFree for the sharingMode parameter of the L_OcrPage_FromBitmap function.

    /* Free the image, if there is one */   
    if (LeadBitmap.Flags.Allocated)   
       L_FreeBitmap (&LeadBitmap); 

  15. On the Build menu, select Build SimpleLoad.exe.

  16. On the Build menu, select Execute SimpleLoad.exe.
    NOTE: Before building project, clean solution and project files. In Build, select Clean Solution and Clean SimpleLoad.
  17. Save this project to use it for testing other code samples.
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LEADTOOLS OCR Module - LEAD Engine C API Help