Convert PDF to All with OCR engine in C#


Since version 7.0, PDF Focus .Net can work with OCR. To perform OCR we'll use free OCR library by Nicomsoft (https://www.nicomsoft.com).
The library is freeware and can be used in commercial application.

You need download Nicomsoft OCR SDK from: free_NSOCR_v70_build885_full.exe



Further install it on your PC or server-side.

Notice: Please make sure, that you have installed this package (Nicomsoft OCR SDK) on your computer. And also, when creating your solution, you must place the file "NSOCR.cs" from C:\Program Files (x86)\Nicomsoft OCR\Samples in the directory of your solution. After copying "NSOCR.cs", there will be no errors with the "using NSOCR_NameSpace;".

How to use SautinSoft.PdfFocus with Optical Character Recognition (OCR).

Complete code

//A C# wrapper class for NSOCR.dll functions (calling NSOCR API via platform invoke)

//******************************************************************************
//                        Nicomsoft OCR DLL interface
//                    Copyright (c) 2010-2016 Nicomsoft
//                 Copyright (c) 2010-2016 Michael Kapustin
//                           www.nsocr.com
//******************************************************************************



using System;
using System.Text;
using System.Runtime.InteropServices;


namespace NSOCR_NameSpace
{
    public class TNSOCR
    {
        //// Error codes
        public const int ERROR_FIRST					= 0x70000000;
        public const int ERROR_FILENOTFOUND 			= 0x70000001;
        public const int ERROR_LOADFILE 				= 0x70000002;
        public const int ERROR_SAVEFILE 				= 0x70000003;
        public const int ERROR_MISSEDIMGLOADER 		    = 0x70000004;
        public const int ERROR_OPTIONNOTFOUND		    = 0x70000005;
        public const int ERROR_NOBLOCKS				    = 0x70000006;
        public const int ERROR_BLOCKNOTFOUND			= 0x70000007;
        public const int ERROR_INVALIDINDEX			    = 0x70000008;
        public const int ERROR_INVALIDPARAMETER		    = 0x70000009;
        public const int ERROR_FAILED				    = 0x7000000A;
        public const int ERROR_INVALIDBLOCKTYPE		    = 0x7000000B;
        public const int ERROR_EMPTYTEXT				= 0x7000000D;
        public const int ERROR_LOADINGDICTIONARY		= 0x7000000E;
        public const int ERROR_LOADCHARBASE			    = 0x7000000F;
        public const int ERROR_NOMEMORY				    = 0x70000010;
        public const int ERROR_CANNOTLOADGS			    = 0x70000011;
        public const int ERROR_CANNOTPROCESSPDF		    = 0x70000012;
        public const int ERROR_NOIMAGE				    = 0x70000013;
        public const int ERROR_MISSEDSTEP		    	= 0x70000014;
        public const int ERROR_OUTOFIMAGE               = 0x70000015;
        public const int ERROR_EXCEPTION                = 0x70000016;
        public const int ERROR_NOTALLOWED               = 0x70000017;
        public const int ERROR_NODEFAULTDEVICE          = 0x70000018;
        public const int ERROR_NOTAPPLICABLE			= 0x70000019;
        public const int ERROR_MISSEDBARCODEDLL         = 0x7000001A;
        public const int ERROR_PENDING                  = 0x7000001B;
        public const int ERROR_OPERATIONCANCELLED       = 0x7000001C;
        public const int ERROR_TOOMANYLANGUAGES         = 0x7000001D;
        public const int ERROR_OPERATIONTIMEOUT         = 0x7000001E;
        public const int ERROR_LOAD_ASIAN_MODULE	= 0x7000001F;	
        public const int ERROR_LOAD_ASIAN_LANG		= 0x70000020;

        public const int ERROR_INVALIDOBJECT			= 0x70010000;
        public const int ERROR_TOOMANYOBJECTS	    	= 0x70010001;
        public const int ERROR_DLLNOTLOADED		    	= 0x70010002;
        public const int ERROR_DEMO                     = 0x70010003;

        ////Block type
        public const int BT_DEFAULT		    = 0;
        public const int BT_OCRTEXT		    = 1; //machine-printed text
        public const int BT_ICRDIGIT        = 2; //handwritten digits 
        public const int BT_CLEAR           = 3;
        public const int BT_PICTURE         = 4;
        public const int BT_ZONING          = 5;
        public const int BT_OCRDIGIT = 6; //machine-printed digits
        public const int BT_BARCODE = 7;
        public const int BT_TABLE = 8;
        public const int BT_MRZ = 9;

        ////Constants for Img_LoadBmpData function
        public const int BMP_24BIT          = 0x00;
        public const int BMP_8BIT         = 0x01;
        public const int BMP_1BIT           = 0x02;
        public const int BMP_32BIT           = 0x03;
        public const int BMP_BOTTOMTOP      = 0x100;

        ////Constants for Img_GetImgText, Blk_GetText and Svr_AddPage functions
        public const int FMT_EDITCOPY = 0x00;
        public const int FMT_EXACTCOPY	= 0x01;

        //for Img_OCR
        public const int OCRSTEP_FIRST			= 0x00; //first step
        public const int OCRSTEP_PREFILTERS		= 0x10; //filters before binarizing: scaling, invert, rotate etc
        public const int OCRSTEP_BINARIZE		= 0x20; //binarize
        public const int OCRSTEP_POSTFILTERS	= 0x50; //bin garbage filter etc
        public const int OCRSTEP_REMOVELINES    = 0x60; //find and remove lines
        public const int OCRSTEP_ZONING         = 0x70; //analyze page layout
        public const int OCRSTEP_OCR			= 0x80; //ocr itself
        public const int OCRSTEP_LAST			= 0xFF; //last step

        //for Img_OCR, "Flags" parameter
        public const int OCRFLAG_NONE			= 0x00; //default mode (blocking)
        public const int OCRFLAG_THREAD			= 0x01; //non-blocking mode
        public const int OCRFLAG_GETRESULT		= 0x02; //get result for non-blocking mode
        public const int OCRFLAG_GETPROGRESS	= 0x03; //get progress
        public const int OCRFLAG_CANCEL         = 0x04; //cancel ocr

        //for Img_DrawToDC and Img_GetBmpData
        public const int DRAW_NORMAL			= 0x00;
        public const int DRAW_BINARY			= 0x01;
        public const int DRAW_GETBPP            = 0x100;

        //values for Blk_Inversion function
        public const int BLK_INVERSE_GET        = -1;
        public const int BLK_INVERSE_SET0       = 0;
        public const int BLK_INVERSE_SET1       = 1;
        public const int BLK_INVERSE_DETECT     = 0x100;

        //for Blk_Rotation function
        public const int BLK_ROTATE_GET         = -1;
        public const int BLK_ROTATE_NONE        = 0x00;
        public const int BLK_ROTATE_90			= 0x01;
        public const int BLK_ROTATE_180			= 0x02;
        public const int BLK_ROTATE_270			= 0x03;
        public const int BLK_ROTATE_ANGLE       = 0x100000;
        public const int BLK_ROTATE_DETECT      = 0x100;

        //for Blk_Mirror function
        public const int BLK_MIRROR_GET         = -1;
        public const int BLK_MIRROR_NONE        = 0x00;
        public const int BLK_MIRROR_H			= 0x01;
        public const int BLK_MIRROR_V			= 0x02;

        //for Svr_Create function   
        public const int SVR_FORMAT_PDF             = 0x01;
        public const int SVR_FORMAT_RTF             = 0x02;
        public const int SVR_FORMAT_TXT_ASCII       = 0x03;
        public const int SVR_FORMAT_TXT_UNICODE     = 0x04;
        public const int SVR_FORMAT_XML             = 0x05;
        public const int SVR_FORMAT_PDFA            = 0x06;

        //for Scan_Enumerate function
        public const int SCAN_GETDEFAULTDEVICE      = 0x01;
        public const int SCAN_SETDEFAULTDEVICE      = 0x100;

        //for Scan_ScanToImg and Scan_ScanToFile functions
        public const int SCAN_NOUI                  = 0x01;
        public const int SCAN_SOURCEADF             = 0x02;
        public const int SCAN_SOURCEAUTO            = 0x04;
        public const int SCAN_DONTCLOSEDS           = 0x08;
        public const int SCAN_FILE_SEPARATE		    = 0x10;

        //for Blk_GetWordFontStyle function
        public const int FONT_STYLE_UNDERLINED	    = 0x01;
        public const int FONT_STYLE_STRIKED		    = 0x02;
        public const int FONT_STYLE_BOLD			= 0x04;
        public const int FONT_STYLE_ITALIC          = 0x08;

        //for Img_GetProperty function, PropertyID parameter
        public const int IMG_PROP_DPIX			= 0x01;	//original DPI
        public const int IMG_PROP_DPIY = 0x02;
        public const int IMG_PROP_BPP = 0x03; //color depth
        public const int IMG_PROP_WIDTH = 0x04;	//original width
        public const int IMG_PROP_HEIGHT = 0x05;	//original height
        public const int IMG_PROP_INVERTED = 0x06;   //image inversion flag after OCR_STEP_PREFILTERS step
        public const int IMG_PROP_SKEW	= 0x07;	//image skew angle after OCR_STEP_PREFILTERS step, multiplied by 1000
        public const int IMG_PROP_SCALE = 0x08;	//image scale factor after OCR_STEP_PREFILTERS step, multiplied by 1000
        public const int IMG_PROP_PAGEINDEX = 0x09; //image page index

        //for "Blk_SetWordRegEx" function
        public const int REGEX_SET				= 0x00;
        public const int REGEX_CLEAR			= 0x01;
        public const int REGEX_CLEAR_ALL		= 0x02;
        public const int REGEX_DISABLE_DICT     = 0x04;
        public const int REGEX_CHECK            = 0x08;

        //for Svr_SetDocumentInfo function
        public const int INFO_PDF_AUTHOR		= 0x01;
        public const int INFO_PDF_CREATOR		= 0x02;
        public const int INFO_PDF_PRODUCER		= 0x03;
        public const int INFO_PDF_TITLE			= 0x04;
        public const int INFO_PDF_SUBJECT		= 0x05;
        public const int INFO_PDF_KEYWORDS      = 0x06;

        //for Blk_GetBarcodeType function
        public const int BARCODE_TYPE_EAN8      = 0x01;
        public const int BARCODE_TYPE_UPCE		= 0x02;
        public const int BARCODE_TYPE_ISBN10	= 0x03;
        public const int BARCODE_TYPE_UPCA		= 0x04;
        public const int BARCODE_TYPE_EAN13		= 0x05;
        public const int BARCODE_TYPE_ISBN13	= 0x06;
        public const int BARCODE_TYPE_ZBAR_I25	= 0x07;
        public const int BARCODE_TYPE_CODE39	= 0x08;
        public const int BARCODE_TYPE_QRCODE	= 0x09;
        public const int BARCODE_TYPE_CODE128	= 0x0A;

        //for "BarCode/TypesMask" configuration option
        public const int BARCODE_TYPE_MASK_EAN8     = 0x01;
        public const int BARCODE_TYPE_MASK_UPCE		= 0x02;
        public const int BARCODE_TYPE_MASK_ISBN10	= 0x04;
        public const int BARCODE_TYPE_MASK_UPCA		= 0x08;
        public const int BARCODE_TYPE_MASK_EAN13	= 0x10;
        public const int BARCODE_TYPE_MASK_ISBN13	= 0x20;
        public const int BARCODE_TYPE_MASK_ZBAR_I25	= 0x40;
        public const int BARCODE_TYPE_MASK_CODE39	= 0x80;
        public const int BARCODE_TYPE_MASK_QRCODE	= 0x100;
        public const int BARCODE_TYPE_MASK_CODE128	= 0x200;

        //for Img_SaveToFile function
        public const int IMG_FORMAT_BMP			=  0;
        public const int IMG_FORMAT_JPEG		=  2;
        public const int IMG_FORMAT_PNG			= 13;
        public const int IMG_FORMAT_TIFF        	= 18;
        public const int IMG_FORMAT_FLAG_BINARIZED	= 0x100;
////////////////////////////////////////////////////////////////////

        //use appropriate path, otherwise you will get "BadImageFormatException"
        //for x86
        public const string LIBNAME = @"..\..\OCR Lib\Bin\NSOCR.dll"; //IMPORTANT: CORRECT PATH TO X86 NSOCR.DLL
        //for x64
        //public const string LIBNAME = @"..\..\OCR Lib\Bin64\NSOCR.dll"; //IMPORTANT: CORRECT PATH TO X64 NSOCR.DLL



        [DllImport(LIBNAME)]
        public static extern int Engine_Initialize();

        [DllImport(LIBNAME)]
        public static extern int Engine_InitializeAdvanced(out int CfgObj, out int OcrObj, out int ImgObj);

        [DllImport(LIBNAME)]
        public static extern int Engine_Uninitialize();

        [DllImport(LIBNAME)]
        public static extern int Engine_SetDataDirectory([MarshalAs(UnmanagedType.LPWStr)] string DirectoryPath);

        [DllImport(LIBNAME)]
        public static extern int Engine_GetVersion([MarshalAs(UnmanagedType.LPWStr)] StringBuilder OptionValue);

        [DllImport(LIBNAME)]
        public static extern int Engine_SetLicenseKey([MarshalAs(UnmanagedType.LPWStr)] string LicenseKey);
////////

        [DllImport(LIBNAME)]
        public static extern int Cfg_Create(out int CfgObj);

        [DllImport(LIBNAME)]
        public static extern int Cfg_Destroy(int CfgObj);

        [DllImport(LIBNAME)]
        public static extern int Cfg_LoadOptions(int CfgObj, [MarshalAs(UnmanagedType.LPWStr)] string FileName);

        [DllImport(LIBNAME)]
        public static extern int Cfg_SaveOptions(int CfgObj, [MarshalAs(UnmanagedType.LPWStr)] string FileName);

        [DllImport(LIBNAME)]
        public static extern int Cfg_LoadOptionsFromString(int CfgObj, [MarshalAs(UnmanagedType.LPWStr)] string XMLString);

        [DllImport(LIBNAME)]
        public static extern int Cfg_SaveOptionsToString(int CfgObj, [MarshalAs(UnmanagedType.LPWStr)] StringBuilder XMLString, int MaxLen);

        [DllImport(LIBNAME)]
        public static extern int Cfg_GetOption(int CfgObj, int BlockType, [MarshalAs(UnmanagedType.LPWStr)] string OptionPath, [MarshalAs(UnmanagedType.LPWStr)] StringBuilder OptionValue, int MaxLen);

        [DllImport(LIBNAME)]
        public static extern int Cfg_SetOption(int CfgObj, int BlockType, [MarshalAs(UnmanagedType.LPWStr)] string OptionPath, [MarshalAs(UnmanagedType.LPWStr)] string OptionValue);

        [DllImport(LIBNAME)]
        public static extern int Cfg_DeleteOption(int CfgObj, int BlockType, [MarshalAs(UnmanagedType.LPWStr)] string OptionPath);

////////

        [DllImport(LIBNAME)]
        public static extern int Ocr_Create(int CfgObj, out int OcrObj);

        [DllImport(LIBNAME)]
        public static extern int Ocr_Destroy(int OcrObj);

        [DllImport(LIBNAME)]
        public static extern int Ocr_Destroy(int ImgObj, int SvrObj, int PageIndexStart, int PageIndexEnd, int OcrObjCnt, int Flags);

        [DllImport(LIBNAME)]
        public static extern int Ocr_ProcessPages(int ImgObj, int SvrObj, int PageIndexStart, int PageIndexEnd, int OcrObjCnt, int Flags);
////////

        [DllImport(LIBNAME)]
        public static extern int Img_Create(int OcrObj, out int ImgObj);

        [DllImport(LIBNAME)]
        public static extern int Img_Destroy(int ImgObj);

        [DllImport(LIBNAME)]
        public static extern int Img_LoadFile(int ImgObj, [MarshalAs(UnmanagedType.LPWStr)] string FileName);

        [DllImport(LIBNAME)]
        public static extern int Img_LoadFromMemory(int ImgObj, IntPtr Bytes, int DataSize);

        [DllImport(LIBNAME)]
        public static extern int Img_LoadBmpData(int ImgObj, IntPtr Bytes, int Width, int Height, int Flags, int Stride);

        [DllImport(LIBNAME)]
        public static extern int Img_Unload(int ImgObj);

        [DllImport(LIBNAME)]
        public static extern int Img_GetPageCount(int ImgObj);

        [DllImport(LIBNAME)]
        public static extern int Img_SetPage(int ImgObj, int PageIndex);

        [DllImport(LIBNAME)]
        public static extern int Img_GetSize(int ImgObj, out int Width, out int Height);

        [DllImport(LIBNAME)]
        public static extern int Img_DrawToDC(int ImgObj, int HandleDC, int X, int Y, ref int Width, ref int Height, int Flags);

        [DllImport(LIBNAME)]
        public static extern int Img_DeleteAllBlocks(int ImgObj);

        [DllImport(LIBNAME)]
        public static extern int Img_AddBlock(int ImgObj, int Xpos, int Ypos, int Width, int Height, out int BlkObj);

        [DllImport(LIBNAME)]
        public static extern int Img_DeleteBlock(int ImgObj, int BlkObj);

        [DllImport(LIBNAME)]
        public static extern int Img_GetBlockCnt(int ImgObj);

        [DllImport(LIBNAME)]
        public static extern int Img_GetBlock(int ImgObj, int BlockIndex, out int BlkObj);

        [DllImport(LIBNAME)]
        public static extern int Img_GetImgText(int ImgObj, [MarshalAs(UnmanagedType.LPWStr)] StringBuilder TextStr, int MaxLen, int Flags);

        [DllImport(LIBNAME)]
        public static extern int Img_GetBmpData(int ImgObj, IntPtr Bits, ref int Width, ref int Height, int Flags);

        [DllImport(LIBNAME)]
        public static extern int Img_OCR(int ImgObj, int FirstStep, int LastStep, int Flags);

        [DllImport(LIBNAME)]
        public static extern int Img_SaveBlocks(int ImgObj, [MarshalAs(UnmanagedType.LPWStr)] string FileName);
	
        [DllImport(LIBNAME)]
        public static extern int Img_LoadBlocks(int ImgObj, [MarshalAs(UnmanagedType.LPWStr)] string FileName);
	
        [DllImport(LIBNAME)]
        public static extern int Img_GetSkewAngle(int ImgObj);

        [DllImport(LIBNAME)]
        public static extern int Img_GetPixLineCnt(int ImgObj);

        [DllImport(LIBNAME)]
        public static extern int Img_GetPixLine(int ImgObj, int LineInd, out int X1pos, out int Y1pos, out int X2pos, out int Y2pos, out int Width);

        [DllImport(LIBNAME)]
        public static extern int Img_GetScaleFactor(int ImgObj);

        [DllImport(LIBNAME)]
        public static extern int Img_CalcPointPosition(int ImgObj, ref int Xpos, ref int Ypos, int Mode);

        [DllImport(LIBNAME)]
        public static extern int Img_CopyCurrentPage(int ImgObjSrc, int ImgObjDst, int Flags);

        [DllImport(LIBNAME)]
        public static extern int Img_GetProperty(int ImgObj, int PropertyID);

        [DllImport(LIBNAME)]
        public static extern int Img_SaveToFile(int ImgObj, [MarshalAs(UnmanagedType.LPWStr)] string FileName, int Format, int Flags);

        [DllImport(LIBNAME)]
        public static extern int Img_SaveToMemory(int ImgObj, IntPtr Bytes, int BufferSize, int Format, int Flags);
////////

        [DllImport(LIBNAME)]
        public static extern int Blk_GetType(int BlkObj);

        [DllImport(LIBNAME)]
        public static extern int Blk_SetType(int BlkObj, int BlockType);

        [DllImport(LIBNAME)]
        public static extern int Blk_GetRect(int BlkObj, out int Xpos, out int Ypos, out int Width, out int Height);

        [DllImport(LIBNAME)]
        public static extern int Blk_GetText(int BlkObj, [MarshalAs(UnmanagedType.LPWStr)] StringBuilder TextStr, int MaxLen, int Flags);

        [DllImport(LIBNAME)]
        public static extern int Blk_GetLineCnt(int BlkObj);

        [DllImport(LIBNAME)]
        public static extern int Blk_GetLineText(int BlkObj, int LineIndex, [MarshalAs(UnmanagedType.LPWStr)] StringBuilder TextStr, int MaxLen);

        [DllImport(LIBNAME)]
        public static extern int Blk_GetWordCnt(int BlkObj, int LineIndex);

        [DllImport(LIBNAME)]
        public static extern int Blk_GetWordText(int BlkObj, int LineIndex, int WordIndex, [MarshalAs(UnmanagedType.LPWStr)] StringBuilder TextStr, int MaxLen);

        [DllImport(LIBNAME)]
        public static extern int Blk_SetWordText(int BlkObj, int LineIndex, int WordIndex, [MarshalAs(UnmanagedType.LPWStr)] string TextStr);

        [DllImport(LIBNAME)]
        public static extern int Blk_GetCharCnt(int BlkObj, int LineIndex, int WordIndex);

        [DllImport(LIBNAME)]
        public static extern int Blk_GetCharRect(int BlkObj, int LineIndex, int WordIndex, int CharIndex, out int Xpos, out int Ypos, out int Width, out int Height);

        [DllImport(LIBNAME)]
        public static extern int Blk_GetCharText(int BlkObj, int LineIndex, int WordIndex, int CharIndex, int ResultIndex, [MarshalAs(UnmanagedType.LPWStr)] StringBuilder TextStr, int MaxLen);

        [DllImport(LIBNAME)]
        public static extern int Blk_GetCharQual(int BlkObj, int LineIndex, int WordIndex, int CharIndex, int ResultIndex);

        [DllImport(LIBNAME)]
        public static extern int Blk_GetTextRect(int BlkObj, int LineIndex, int WordIndex, out int Xpos, out int Ypos, out int Width, out int Height);

        [DllImport(LIBNAME)]
        public static extern int Blk_Inversion(int BlkObj, int Inversion);

        [DllImport(LIBNAME)]
        public static extern int Blk_Rotation(int BlkObj, int Rotation);

        [DllImport(LIBNAME)]
        public static extern int Blk_Mirror(int BlkObj, int Mirror);

        [DllImport(LIBNAME)]
        public static extern int Blk_IsWordInDictionary(int BlkObj, int LineIndex, int WordIndex);

        [DllImport(LIBNAME)]
        public static extern int Blk_SetRect(int BlkObj, int Xpos, int Ypos, int Width, int Height);

        [DllImport(LIBNAME)]
        public static extern int Blk_GetWordQual(int BlkObj, int LineIndex, int WordIndex);

        [DllImport(LIBNAME)]
        public static extern int Blk_GetWordFontColor(int BlkObj, int LineIndex, int WordIndex);

        [DllImport(LIBNAME)]
        public static extern int Blk_GetWordFontSize(int BlkObj, int LineIndex, int WordIndex);

        [DllImport(LIBNAME)]
        public static extern int Blk_GetWordFontStyle(int BlkObj, int LineIndex, int WordIndex);

        [DllImport(LIBNAME)]
        public static extern int Blk_GetBackgroundColor(int BlkObj);

        [DllImport(LIBNAME)]
        public static extern int Blk_SetWordRegEx(int BlkObj, int LineIndex, int WordIndex, [MarshalAs(UnmanagedType.LPWStr)] string RegEx, int Flags);

        [DllImport(LIBNAME)]
        public static extern int Blk_GetBarcodeCnt(int BlkObj);

        [DllImport(LIBNAME)]
        public static extern int Blk_GetBarcodeText(int BlkObj, int BarcodeInd, [MarshalAs(UnmanagedType.LPWStr)] StringBuilder TextStr, int MaxLen);

        [DllImport(LIBNAME)]
        public static extern int Blk_GetBarcodeRect(int BlkObj, int BarcodeInd, out int Xpos, out int Ypos, out int Width, out int Height);

        [DllImport(LIBNAME)]
        public static extern int Blk_GetBarcodeType(int BlkObj, int BarcodeInd);

        ////////

        [DllImport(LIBNAME)]
        public static extern int Svr_Create(int CfgObj, int Format, out int SvrObj);

        [DllImport(LIBNAME)]
        public static extern int Svr_Destroy(int SvrObj);

        [DllImport(LIBNAME)]
        public static extern int Svr_NewDocument(int SvrObj);

        [DllImport(LIBNAME)]
        public static extern int Svr_AddPage(int SvrObj, int ImgObj, int Flags);

        [DllImport(LIBNAME)]
        public static extern int Svr_SaveToFile(int SvrObj, [MarshalAs(UnmanagedType.LPWStr)] string FileName);

        [DllImport(LIBNAME)]
        public static extern int Svr_SaveToMemory(int SvrObj, IntPtr Bytes, int BufferSize);

        [DllImport(LIBNAME)]
        public static extern int Svr_GetText(int SvrObj, int PageIndex, [MarshalAs(UnmanagedType.LPWStr)] StringBuilder TextStr, int MaxLen);

        [DllImport(LIBNAME)]
        public static extern int Svr_SetDocumentInfo(int SvrObj, int InfoID, [MarshalAs(UnmanagedType.LPWStr)] string InfoStr);

        ////////

        [DllImport(LIBNAME)]
        public static extern int Scan_Create(int CfgObj, out int ScanObj);

        [DllImport(LIBNAME)]
        public static extern int Scan_Destroy(int ScanObj);

        [DllImport(LIBNAME)]
        public static extern int Scan_Enumerate(int ScanObj, [MarshalAs(UnmanagedType.LPWStr)] StringBuilder ScannerNames, int MaxLen, int Flags);

        [DllImport(LIBNAME)]
        public static extern int Scan_ScanToImg(int ScanObj, int ImgObj, int ScannerIndex, int Flags);

        [DllImport(LIBNAME)]
        public static extern int Scan_ScanToFile(int ScanObj, [MarshalAs(UnmanagedType.LPWStr)] string FileName, int ScannerIndex, int Flags);
    }
}

Download

'A VB.NET wrapper class for NSOCR

'******************************************************************************
'                        Nicomsoft OCR DLL interface
'                    Copyright (c) 2010-2016 Nicomsoft
'                 Copyright (c) 2010-2016 Michael Kapustin
'                           www.nsocr.com
'******************************************************************************


Public Class TNSOCR

    'error codes
    Public Const ERROR_FIRST = &H70000000
    Public Const ERROR_FILENOTFOUND = &H70000001
    Public Const ERROR_LOADFILE = &H70000002
    Public Const ERROR_SAVEFILE = &H70000003
    Public Const ERROR_MISSEDIMGLOADER = &H70000004
    Public Const ERROR_OPTIONNOTFOUND = &H70000005
    Public Const ERROR_NOBLOCKS = &H70000006
    Public Const ERROR_BLOCKNOTFOUND = &H70000007
    Public Const ERROR_INVALIDINDEX = &H70000008
    Public Const ERROR_INVALIDPARAMETER = &H70000009
    Public Const ERROR_FAILED = &H7000000A
    Public Const ERROR_INVALIDBLOCKTYPE = &H7000000B
    Public Const ERROR_EMPTYTEXT = &H7000000D
    Public Const ERROR_LOADINGDICTIONARY = &H7000000E
    Public Const ERROR_LOADCHARBASE = &H7000000F
    Public Const ERROR_NOMEMORY = &H70000010
    Public Const ERROR_CANNOTLOADGS = &H70000011
    Public Const ERROR_CANNOTPROCESSPDF = &H70000012
    Public Const ERROR_NOIMAGE = &H70000013
    Public Const ERROR_MISSEDSTEP = &H70000014
    Public Const ERROR_OUTOFIMAGE = &H70000015
    Public Const ERROR_EXCEPTION = &H70000016
    Public Const ERROR_NOTALLOWED = &H70000017
    Public Const ERROR_NODEFAULTDEVICE = &H70000018
    Public Const ERROR_NOTAPPLICABLE = &H70000019
    Public Const ERROR_MISSEDBARCODEDLL = &H7000001A
    Public Const ERROR_PENDING = &H7000001B
    Public Const ERROR_OPERATIONCANCELLED = &H7000001C
    Public Const ERROR_TOOMANYLANGUAGES = &H7000001D
    Public Const ERROR_OPERATIONTIMEOUT = &H7000001E
    Public Const ERROR_LOAD_ASIAN_MODULE= &H7000001F	
    Public Const ERROR_LOAD_ASIAN_LANG	= &H70000020
    Public Const ERROR_INVALIDOBJECT = &H70010000
    Public Const ERROR_TOOMANYOBJECTS = &H70010001
    Public Const ERROR_DLLNOTLOADED = &H70010002
    Public Const ERROR_DEMO = &H70010003

    'block types
    Public Const BT_DEFAULT = 0
    Public Const BT_OCRTEXT = 1
    Public Const BT_ICRDIGIT = 2
    Public Const BT_CLEAR = 3
    Public Const BT_PICTURE = 4
    Public Const BT_ZONING = 5
    Public Const BT_OCRDIGIT = 6
    Public Const BT_BARCODE = 7
    Public Const BT_TABLE = 8
    Public Const BT_MRZ = 9

    'Constants for Img_LoadBmpData function
    Public Const BMP_24BIT = &H0
    Public Const BMP_8BIT = &H1
    Public Const BMP_1BIT = &H2
    Public Const BMP_32BIT = &H3
    Public Const BMP_BOTTOMTOP = &H100

    'Constants for Img_GetImgText, Blk_GetText and Svr_AddPage functions
    Public Const FMT_EDITCOPY = &H0
    Public Const FMT_EXACTCOPY = &H1

    'for Img_OCR
    Public Const OCRSTEP_FIRST = &H0 'first step
    Public Const OCRSTEP_PREFILTERS = &H10 'filters before binarizing: scaling, invert, rotate etc
    Public Const OCRSTEP_BINARIZE = &H20 'binarize
    Public Const OCRSTEP_POSTFILTERS = &H50 'bin garbage filter etc
    Public Const OCRSTEP_REMOVELINES = &H60 'find and remove lines
    Public Const OCRSTEP_ZONING = &H70 'analyze page layout
    Public Const OCRSTEP_OCR = &H80 'ocr itself
    Public Const OCRSTEP_LAST = &HFF 'last step

    'for Img_OCR, "Flags" parameter
    Public Const OCRFLAG_NONE = &H0 'default mode (blocking)
    Public Const OCRFLAG_THREAD = &H1 'non-blocking mode
    Public Const OCRFLAG_GETRESULT = &H2 'get result for non-blocking mode
    Public Const OCRFLAG_GETPROGRESS = &H3 'get progress
    Public Const OCRFLAG_CANCEL = &H4 'cancel ocr

    'for Img_DrawToDC and Img_GetBmpData
    Public Const DRAW_NORMAL = &H0
    Public Const DRAW_BINARY = &H1
    Public Const DRAW_GETBPP = &H100

    'values for Blk_Inversion function
    Public Const BLK_INVERSE_GET = -1
    Public Const BLK_INVERSE_SET0 = 0
    Public Const BLK_INVERSE_SET1 = 1
    Public Const BLK_INVERSE_DETECT = &H100

    'for Blk_Rotation function
    Public Const BLK_ROTATE_GET = -1
    Public Const BLK_ROTATE_NONE = 0
    Public Const BLK_ROTATE_90 = &H1
    Public Const BLK_ROTATE_180 = &H2
    Public Const BLK_ROTATE_270 = &H3
    Public Const BLK_ROTATE_ANGLE = &H100000
    Public Const BLK_ROTATE_DETECT = &H100

    'for Blk_Mirror function
    Public Const BLK_MIRROR_GET = -1
    Public Const BLK_MIRROR_H = &H1
    Public Const BLK_MIRROR_V = &H2

    'for Svr_Create function   
    Public Const SVR_FORMAT_PDF = &H1
    Public Const SVR_FORMAT_RTF = &H2
    Public Const SVR_FORMAT_TXT_ASCII = &H3
    Public Const SVR_FORMAT_TXT_UNICODE = &H4
    Public Const SVR_FORMAT_XML = &H5
    Public Const SVR_FORMAT_PDFA = &H6

    'for Scan_Enumerate function
    Public Const SCAN_GETDEFAULTDEVICE = &H1
    Public Const SCAN_SETDEFAULTDEVICE = &H100

    'for Scan_ScanToImg and Scan_ScanToFile functions
    Public Const SCAN_NOUI = &H1
    Public Const SCAN_SOURCEADF = &H2
    Public Const SCAN_SOURCEAUTO = &H4
    Public Const SCAN_DONTCLOSEDS = &H8
    Public Const SCAN_FILE_SEPARATE = &H10

    'for Blk_GetWordFontStyle function
    Public Const FONT_STYLE_UNDERLINED = &H1
    Public Const FONT_STYLE_STRIKED = &H2
    Public Const FONT_STYLE_BOLD = &H4
    Public Const FONT_STYLE_ITALIC = &H8

    'for Img_GetProperty function, PropertyID parameter
    Public Const IMG_PROP_DPIX = &H1   'original DPI
    Public Const IMG_PROP_DPIY = &H2
    Public Const IMG_PROP_BPP = &H3   'color depth
    Public Const IMG_PROP_WIDTH = &H4   'original width
    Public Const IMG_PROP_HEIGHT = &H5   'original height
    Public Const IMG_PROP_INVERTED = &H6    'image was inverted
    Public Const IMG_PROP_SKEW = &H7   'image skew angle after OCR_STEP_PREFILTERS step, multiplied by 1000
    Public Const IMG_PROP_SCALE = &H8   'image scale factor after OCR_STEP_PREFILTERS step, multiplied by 1000
    Public Const IMG_PROP_PAGEINDEX = &H9 'image page index

    'for "Blk_SetWordRegEx" function
    Public Const REGEX_SET = &H0
    Public Const REGEX_CLEAR = &H1
    Public Const REGEX_CLEAR_ALL = &H2
    Public Const REGEX_DISABLE_DICT = &H4
    Public Const REGEX_CHECK = &H8

    'for Svr_SetDocumentInfo function
    Public Const INFO_PDF_AUTHOR = &H1
    Public Const INFO_PDF_CREATOR = &H2
    Public Const INFO_PDF_PRODUCER = &H3
    Public Const INFO_PDF_TITLE = &H4
    Public Const INFO_PDF_SUBJECT = &H5
    Public Const INFO_PDF_KEYWORDS = &H6

    'for Blk_GetBarcodeType function
    Public Const BARCODE_TYPE_EAN8 = &H1
    Public Const BARCODE_TYPE_UPCE = &H2
    Public Const BARCODE_TYPE_ISBN10 = &H3
    Public Const BARCODE_TYPE_UPCA = &H4
    Public Const BARCODE_TYPE_EAN13 = &H5
    Public Const BARCODE_TYPE_ISBN13 = &H6
    Public Const BARCODE_TYPE_ZBAR_I25 = &H7
    Public Const BARCODE_TYPE_CODE39 = &H8
    Public Const BARCODE_TYPE_QRCODE = &H9
    Public Const BARCODE_TYPE_CODE128 = &HA

    'for "BarCode/TypesMask" configuration option
    Public Const BARCODE_TYPE_MASK_EAN8 = &H1
    Public Const BARCODE_TYPE_MASK_UPCE = &H2
    Public Const BARCODE_TYPE_MASK_ISBN10 = &H4
    Public Const BARCODE_TYPE_MASK_UPCA = &H8
    Public Const BARCODE_TYPE_MASK_EAN13 = &H10
    Public Const BARCODE_TYPE_MASK_ISBN13 = &H20
    Public Const BARCODE_TYPE_MASK_ZBAR_I25 = &H40
    Public Const BARCODE_TYPE_MASK_CODE39 = &H80
    Public Const BARCODE_TYPE_MASK_QRCODE = &H100
    Public Const BARCODE_TYPE_MASK_CODE128 = &H200

    'for Img_SaveToFile function
    Public Const IMG_FORMAT_BMP = 0
    Public Const IMG_FORMAT_JPEG = 2
    Public Const IMG_FORMAT_PNG = 13
    Public Const IMG_FORMAT_TIFF = 18
    Public Const IMG_FORMAT_FLAG_BINARIZED = &H100
End Class

Download

If you need a new code example or have a question: email us at support@sautinsoft.com or ask at Online Chat (right-bottom corner of this page) or use the Form below:


Questions and suggestions from you are always welcome!

We are developing .Net components since 2002. We know PDF, DOCX, RTF, HTML, XLSX and Images formats. If you need any assistance with creating, modifying or converting documents in various formats, we can help you. We will write any code example for you absolutely free.