Overloads Overridable Function AddPage( _
   ByVal stream As Stream, _
   ByVal callback As OcrProgressCallback _
) As IOcrPage

Visual Basic (Usage)	Copy Code
Dim instance As IOcrPageCollection Dim stream As Stream Dim callback As OcrProgressCallback Dim value As IOcrPage   value = instance.AddPage(stream, callback)

virtual IOcrPage AddPage( 
   Stream stream,
   OcrProgressCallback callback
)

virtual IOcrPage^ AddPage( 
   Stream^ stream,
   OcrProgressCallback^ callback
) 

Parameters

stream

A .NET stream containing the image.

callback

Optional callback to show operation progress.

Return Value

This example will add a raster image stored in a memory stream to the OCR engine.

Visual Basic

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Public Sub AddPageFromStreamExample()    ' 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 tifFileName As String = LeadtoolsExamples.Common.ImagesPath.Path + "Ocr1.tif"    Dim pdfFileName As String = LeadtoolsExamples.Common.ImagesPath.Path + "Ocr1.pdf"    ' Load the TIF image into a memory stream    Dim ms As New MemoryStream()    Using fs As FileStream = File.OpenRead(tifFileName)       Dim bufferSize As Integer = 1024 * 4       Dim buffer(bufferSize - 1) As Byte       Dim bytes As Integer = 0       Do          bytes = fs.Read(buffer, 0, bufferSize)          If (bytes > 0) Then             ms.Write(buffer, 0, bytes)          End If       Loop While (bytes > 0)    End Using    ' Reset the stream position    ms.Position = 0    ' 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 the image          ocrDocument.Pages.AddPage(ms, Nothing)          ' We do not need the stream anymore          ms.Dispose()          ' Recognize          ocrDocument.Pages.Recognize(Nothing)          ' Save          ocrDocument.Save(pdfFileName, DocumentFormat.Pdf, Nothing)       End Using       ' Shutdown the engine       ' Note: calling Dispose will also automatically shutdown the engine if it has been started       ocrEngine.Shutdown()    End Using End Sub

C#

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public void AddPageFromStreamExample()  {     // 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 tifFileName = LeadtoolsExamples.Common.ImagesPath.Path + "Ocr1.tif";     string pdfFileName = LeadtoolsExamples.Common.ImagesPath.Path + "Ocr1.pdf";       // Load the TIF image into a memory stream     MemoryStream ms = new MemoryStream();       using(FileStream fs = File.OpenRead(tifFileName))     {        const int bufferSize = 1024 * 4;        byte[] buffer = new byte[bufferSize];        int bytes = 0;        do        {           bytes = fs.Read(buffer, 0, bufferSize);           if(bytes > 0)              ms.Write(buffer, 0, bytes);        }        while(bytes > 0);     }       // Reset the stream position     ms.Position = 0;       // 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 the image           ocrDocument.Pages.AddPage(ms, null);             // We do not need the stream anymore           ms.Dispose();             // Recognize           ocrDocument.Pages.Recognize(null);             // Save           ocrDocument.Save(pdfFileName, DocumentFormat.Pdf, null);        }          // Shutdown the engine        // Note: calling Dispose will also automatically shutdown the engine if it has been started        ocrEngine.Shutdown();     }  }

This method will load the first page from a raster image stored inside a .NET stream and adds it to the OCR document.

To add all or specific range of the pages of a multi-page image file stored in a .NET stream to the OCR document, use the AddPages(Stream stream, int imageFirstPageNumber, int imageLastPageNumber, OcrProgressCallback callback) method.

This method will add the page to the end of the collection if you already have pages in this IOcrPageCollection.

If you passed a RasterCodecs object to the IOcrEngine.Startup, then this method will use the same RasterCodecs object to load the raster image file. If you did not pass a RasterCodecs object, the engine will create an instance the first time one of the add or export page methods is called.

The image file in stream can be any of the file formats supported by LEADTOOLS. For more information, refer to Summary of All Supported Image File Formats.

You can use the OcrProgressCallback to show the operation progress or to abort it. For more information and an example, refer to OcrProgressCallback.

The LEADTOOLS OCR engine supports pages of dots per inch (DPI) values of 150 and greater. If you try to add a page with a DPI of less than 150 then the engine might be able to recognize any data from this page.

Note, the LEADTOOLS Plus OCR engine does not support image size greater than A3 paper size (11.7 by 16.5 inches at 300 dpi). Attempting to add an image that has a size greater than A3 will result in an error. For document of size greater than the maximum allowed, you must first resize the image before adding it to the LEADTOOLS Plus OCR engine. The Professional and Advantage engines do not have a restriction on the image size.

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

Reference