OcrProgressCallback Delegate

Monitors progress of OCR operations.

Syntax

C#
Visual Basic
WinRT C#
Java
Objective-C
WinRT JavaScript
C++

public delegate void OcrProgressCallback( 
   IOcrProgressData data
)

'Declaration

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

'Usage

Dim instance As New OcrProgressCallback(AddressOf HandlerMethod)

public delegate void OcrProgressCallback( 
   IOcrProgressData data
)

typedef void (^LTOcrProgressHandler)(LTOcrProgressData *progressData)

void OcrProgressListener.onProgress(OcrProgressData data)

OcrProgressCallback( 
   data 
)

public delegate void OcrProgressCallback( 
   IOcrProgressData^ data
)

Parameters

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

Remarks

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.

Example

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.

C#
Visual Basic
WinRT C#
WinRT JavaScript
Silverlight C#
Silverlight VB

Copy Code

Imports Leadtools
Imports Leadtools.Codecs
Imports Leadtools.Forms.Ocr
Imports Leadtools.Forms.DocumentWriters
Imports Leadtools.Forms
Imports Leadtools.WinForms

' Text writer to save the log to
Private _log As StreamWriter
<TestMethod>
Public Sub OcrProgressCallbackExample()
   Dim logFileName As String = Path.Combine(LEAD_VARS.ImagesDir, "log.txt")
   Dim multiPageTifFileName As String = Path.Combine(LEAD_VARS.ImagesDir, "Ocr.tif")
   Dim pdfFileName As String = Path.Combine(LEAD_VARS.ImagesDir, "Ocr1.pdf")

   ' Create the log text writer
   _log = File.CreateText(logFileName)

   ' Create an instance of the engine
   Using ocrEngine As IOcrEngine = OcrEngineManager.CreateEngine(OcrEngineType.Advantage, False)
      ' Start the engine using default parameters
      ocrEngine.Startup(Nothing, Nothing, Nothing, LEAD_VARS.OcrAdvantageRuntimeDir)

      ' 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, New OcrProgressCallback(AddressOf MyOcrProgressCallback))

         ' Auto-recognize the zones in all the pages
         _log.WriteLine("Auto-zoning")
         _log.WriteLine("********************************")
         ocrDocument.Pages.AutoZone(New OcrProgressCallback(AddressOf MyOcrProgressCallback))

         ' Recognize it and save it as PDF
         _log.WriteLine("Recognizing")
         _log.WriteLine("********************************")
         ocrDocument.Pages.Recognize(New OcrProgressCallback(AddressOf MyOcrProgressCallback))
         _log.WriteLine("Saving to PDF")
         _log.WriteLine("********************************")
         ocrDocument.Save(pdfFileName, DocumentFormat.Pdf, New OcrProgressCallback(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(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

Public NotInheritable Class LEAD_VARS
Public Const ImagesDir As String = "C:\Users\Public\Documents\LEADTOOLS Images"
Public Const OcrAdvantageRuntimeDir As String = "C:\LEADTOOLS 19\Bin\Common\OcrAdvantageRuntime"
End Class

using Leadtools;
using Leadtools.Codecs;
using Leadtools.Forms.Ocr;
using Leadtools.Forms.DocumentWriters;
using Leadtools.Forms;
using Leadtools.WinForms;

public void OcrProgressCallbackExample()
{
   string logFileName = Path.Combine(LEAD_VARS.ImagesDir, "log.txt");
   string multiPageTifFileName = Path.Combine(LEAD_VARS.ImagesDir, "Ocr.tif");
   string pdfFileName = Path.Combine(LEAD_VARS.ImagesDir, "Ocr1.pdf");
   // Create the log text writer
   _log = File.CreateText(logFileName);

   // Create an instance of the engine
   using (IOcrEngine ocrEngine = OcrEngineManager.CreateEngine(OcrEngineType.Advantage, false))
   {
      // Start the engine using default parameters
      ocrEngine.Startup(null, null, null, LEAD_VARS.OcrAdvantageRuntimeDir);

      // 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();
}
// Text writer to save the log to
private StreamWriter _log;

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);
}

static class LEAD_VARS
{
public const string ImagesDir = @"C:\Users\Public\Documents\LEADTOOLS Images";
public const string OcrAdvantageRuntimeDir = @"C:\LEADTOOLS 19\Bin\Common\OcrAdvantageRuntime";
}

using Leadtools;
using Leadtools.Codecs;
using Leadtools.Forms.Ocr;
using Leadtools.Forms.DocumentWriters;
using Leadtools.Forms;

// Text writer to save the log to
private DataWriter _log;
private IRandomAccessStream _fileStream;
private IOutputStream _outputStream;
      
public async Task OcrProgressCallbackExample()
{
   string logFileName = @"log.txt";
   string tifFileName = @"Assets\Ocr1.tif";
   string pdfFileName = @"Ocr1.pdf";

   // Create the log text writer
   StorageFile file = await Tools.AppLocalFolder.CreateFileAsync(logFileName);
   _fileStream = await file.OpenAsync(FileAccessMode.ReadWrite);

   _outputStream = _fileStream.GetOutputStreamAt(0);
   _log = new DataWriter(_outputStream);

   // Create an instance of the engine
   IOcrEngine ocrEngine = OcrEngineManager.CreateEngine(OcrEngineType.Advantage, false);

   // Start the engine using default parameters
   ocrEngine.Startup(null, null, String.Empty, Tools.OcrEnginePath);

   // Create an OCR document
   IOcrDocument ocrDocument = ocrEngine.DocumentManager.CreateDocument();

   // Add this image to the document
   _log.WriteString("Adding the pages\r\n");
   _log.WriteString("********************************\r\n");

   using (RasterCodecs codecs = new RasterCodecs())
   {
      StorageFile loadFile = await Tools.AppInstallFolder.GetFileAsync(tifFileName);
      using (RasterImage image = await codecs.LoadAsync(LeadStreamFactory.Create(loadFile)))
         ocrDocument.Pages.AddPage(image, new OcrProgressCallback(MyOcrProgressCallback));
   }

   // Auto-recognize the zones in all the pages
   _log.WriteString("Auto-zoning\r\n");
   _log.WriteString("********************************\r\n");
   ocrDocument.Pages.AutoZone(new OcrProgressCallback(MyOcrProgressCallback));

   // Recognize it and save it as PDF
   _log.WriteString("Recognizing\r\n");
   _log.WriteString("********************************\r\n");
   ocrDocument.Pages.Recognize(new OcrProgressCallback(MyOcrProgressCallback));
   _log.WriteString("Saving to PDF\r\n");
   _log.WriteString("********************************\r\n");
   StorageFile saveFile = await Tools.AppLocalFolder.CreateFileAsync(pdfFileName, CreationCollisionOption.ReplaceExisting);
   await ocrDocument.SaveAsync(LeadStreamFactory.Create(saveFile), DocumentFormat.Pdf, new OcrProgressCallback(MyOcrProgressCallback));

   // Shutdown the engine
   ocrEngine.Shutdown();

   _log.WriteString("********************************\r\n");
   _log.WriteString("Complete\r\n");

   await _log.StoreAsync();
   _log.DetachStream();
   await _outputStream.FlushAsync();
   _fileStream.Dispose();
}

private void MyOcrProgressCallback(IOcrProgressData data)
{
   if(data.Percentage == 0)
      _log.WriteString("--------------------------\r\n");

   _log.WriteString(string.Format("Page:{0}({1}:{2}) {3}% Operation:{4}\r\n",
      data.CurrentPageIndex,
      data.FirstPageIndex,
      data.LastPageIndex,
      data.Percentage,
      data.Operation));
}

Requirements

Target Platforms

Reference

OcrProgressCallback Members
Leadtools.Forms.Ocr Namespace
IOcrProgressData Interface
OcrProgressOperation Enumeration
OcrProgressStatus Enumeration
IOcrEngine Interface
Programming with the LEADTOOLS .NET OCR