Public Delegate Sub OcrProgressCallback( _
   ByVal data As IOcrProgressData _
) 

Visual Basic (Usage)	Copy Code
Dim instance As New OcrProgressCallback(AddressOf HandlerMethod)

public delegate void OcrProgressCallback( 
   IOcrProgressData data
)

public delegate void OcrProgressCallback( 
   IOcrProgressData^ data
)

Parameters

data

An instance of the IOcrProgressData interface containing the progress callback data.

This example will display a simple "Processing" Windows Forms dialog that can be used to show OCR operation progress as well as allow the user to abort the current operation. You can plug this dialog into your application and call it in response to user-interface commands that correspond to OCR operations.

Visual Basic

Copy Code

' Text writer to save the log to Private _log As StreamWriter Public Sub OcrProgressCallbackExample()    ' Unlock the support needed for LEADTOOLS Plus OCR engine    RasterSupport.Unlock(RasterSupportType.Document, "Replace with your own key here")    RasterSupport.Unlock(RasterSupportType.OcrPlus, "Replace with your own key here")    RasterSupport.Unlock(RasterSupportType.OcrPlusPdfLeadOutput, "Replace with your own key here")    Dim logFileName As String = LeadtoolsExamples.Common.ImagesPath.Path + "log.txt"    Dim multiPageTifFileName As String = LeadtoolsExamples.Common.ImagesPath.Path + "Ocr.tif"    Dim pdfFileName As String = LeadtoolsExamples.Common.ImagesPath.Path + "Ocr1.pdf"    ' Create the log text writer    _log = File.CreateText(logFileName)    ' Create an instance of the engine    Using ocrEngine As IOcrEngine = OcrEngineManager.CreateEngine(OcrEngineType.Plus, False)       ' Start the engine using default parameters       ocrEngine.Startup(Nothing, Nothing, Nothing, Nothing)       ' Create an OCR document       Using ocrDocument As IOcrDocument = ocrEngine.DocumentManager.CreateDocument()          ' Add this image to the document          _log.WriteLine("Adding the pages")          _log.WriteLine("********************************")          ocrDocument.Pages.AddPages(multiPageTifFileName, 1, -1, AddressOf MyOcrProgressCallback)          ' Auto-recognize the zones in all the pages          _log.WriteLine("Auto-zoning")          _log.WriteLine("********************************")          ocrDocument.Pages.AutoZone(AddressOf MyOcrProgressCallback)          ' Recognize it and save it as PDF          _log.WriteLine("Recognizing")          _log.WriteLine("********************************")          ocrDocument.Pages.Recognize(AddressOf MyOcrProgressCallback)          _log.WriteLine("Saving to PDF")          _log.WriteLine("********************************")          ocrDocument.Save(pdfFileName, DocumentFormat.Pdf, AddressOf MyOcrProgressCallback)       End Using       ' Shutdown the engine       ' Note: calling Dispose will also automatically shutdown the engine if it has been started       ocrEngine.Shutdown()    End Using    _log.WriteLine("********************************")    _log.WriteLine("Complete")    _log.Flush()    _log.Close() End Sub Private Sub MyOcrProgressCallback(ByVal data As IOcrProgressData)    If (Data.Percentage = 0) Then       _log.WriteLine("--------------------------")    End If    _log.WriteLine("Page:{0}({1}:{2}) {3}% Operation:{4}", _       data.CurrentPageIndex.ToString("00"), _       data.FirstPageIndex.ToString("00"), _       data.LastPageIndex.ToString("00"), _       data.Percentage.ToString("000"), _       data.Operation) End Sub

C#

Copy Code

// Text writer to save the log to  private StreamWriter _log;  public void OcrProgressCallbackExample()  {     // Unlock the support needed for LEADTOOLS Plus OCR engine     RasterSupport.Unlock(RasterSupportType.Document, "Replace with your own key here");     RasterSupport.Unlock(RasterSupportType.OcrPlus, "Replace with your own key here");     RasterSupport.Unlock(RasterSupportType.OcrPlusPdfLeadOutput, "Replace with your own key here");       string logFileName = LeadtoolsExamples.Common.ImagesPath.Path + "log.txt";     string multiPageTifFileName = LeadtoolsExamples.Common.ImagesPath.Path + "Ocr.tif";     string pdfFileName = LeadtoolsExamples.Common.ImagesPath.Path + "Ocr1.pdf";       // Create the log text writer     _log = File.CreateText(logFileName);       // Create an instance of the engine     using(IOcrEngine ocrEngine = OcrEngineManager.CreateEngine(OcrEngineType.Plus, false))     {        // Start the engine using default parameters        ocrEngine.Startup(null, null, null, null);          // Create an OCR document        using(IOcrDocument ocrDocument = ocrEngine.DocumentManager.CreateDocument())        {           // Add this image to the document           _log.WriteLine("Adding the pages");           _log.WriteLine("********************************");           ocrDocument.Pages.AddPages(multiPageTifFileName, 1, -1, new OcrProgressCallback(MyOcrProgressCallback));             // Auto-recognize the zones in all the pages           _log.WriteLine("Auto-zoning");           _log.WriteLine("********************************");           ocrDocument.Pages.AutoZone(new OcrProgressCallback(MyOcrProgressCallback));             // Recognize it and save it as PDF           _log.WriteLine("Recognizing");           _log.WriteLine("********************************");           ocrDocument.Pages.Recognize(new OcrProgressCallback(MyOcrProgressCallback));           _log.WriteLine("Saving to PDF");           _log.WriteLine("********************************");           ocrDocument.Save(pdfFileName, DocumentFormat.Pdf, new OcrProgressCallback(MyOcrProgressCallback));        }          // Shutdown the engine        // Note: calling Dispose will also automatically shutdown the engine if it has been started        ocrEngine.Shutdown();     }       _log.WriteLine("********************************");     _log.WriteLine("Complete");     _log.Flush();     _log.Close();  }    private void MyOcrProgressCallback(IOcrProgressData data)  {     if(data.Percentage == 0)        _log.WriteLine("--------------------------");       _log.WriteLine("Page:{0}({1}:{2}) {3}% Operation:{4}",        data.CurrentPageIndex.ToString("00"),        data.FirstPageIndex.ToString("00"),        data.LastPageIndex.ToString("00"),        data.Percentage.ToString("000"),        data.Operation);  }

The OCR engine will continuously invoke the callback procedure during the different OCR operations with an instance of IOcrProgressData providing the current processing stage and a percentage indicator value. Use this function to indicate progress of application operations.

The callback can set the IOcrProgressData.Status property at any time to OcrProgressStatus.Abort to abort the OCR process and cancel all pending operations.

Target Platforms: Microsoft .NET Framework 3.0, Windows XP, Windows Server 2003 family, Windows Server 2008 family

Reference