Overridable Function AddDib( _
   ByVal dib As IntPtr, _
   ByVal callback As OcrProgressCallback _
) As IOcrPage

Visual Basic (Usage)	Copy Code
Dim instance As IOcrPageCollection Dim dib As IntPtr Dim callback As OcrProgressCallback Dim value As IOcrPage   value = instance.AddDib(dib, callback)

virtual IOcrPage AddDib( 
   IntPtr dib,
   OcrProgressCallback callback
)

virtual IOcrPage^ AddDib( 
   IntPtr dib,
   OcrProgressCallback^ callback
) 

Parameters

dib

An unmanaged pointer to the DIB (device-independent bitmap).

callback

Optional callback to show operation progress.

Return Value

This example will add a raster image stored in an HTTP location to an OCR document

Visual Basic

Copy Code

Public Sub AddPageFromDibExample()    ' 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 bmpFileName As String = LeadtoolsExamples.Common.ImagesPath.Path + "Ocr1.bmp"    Dim pdfFileName As String = LeadtoolsExamples.Common.ImagesPath.Path + "Ocr1.pdf"    ' Get a DIB    ' In this example, we will save the TIF file as BMP, then load it without the BITMAPFILEHEADER structure    ' The result is a valid Windows DIB    RasterCodecs.Startup()    Using codecs As New RasterCodecs()       codecs.Convert(tifFileName, bmpFileName, RasterImageFormat.Bmp, 0, 0, 1, Nothing)    End Using    RasterCodecs.Shutdown()    ' From MSDN    Dim bitmapFileHeaderStructSize As Integer = 14    Dim dib As IntPtr = IntPtr.Zero    Using fs As FileStream = File.OpenRead(bmpFileName)       ' Allocate the DIB       Dim dibSize As Integer = CType(fs.Length - bitmapFileHeaderStructSize, Integer)       dib = Marshal.AllocHGlobal(dibSize)       Dim dibOffset As Integer = 0       ' Now read it       fs.Seek(bitmapFileHeaderStructSize, SeekOrigin.Begin)       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             Dim dibPtr As New IntPtr(dib.ToInt64() + dibOffset)             Marshal.Copy(buffer, 0, dibPtr, bytes)             dibOffset += bytes          End If       Loop While (bytes > 0)    End Using    ' 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.AddDib(dib, Nothing)          ' Free the DIB since we do not need it anymore          Marshal.FreeHGlobal(dib)          ' 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 AddPageFromDibExample()  {     // 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 bmpFileName = LeadtoolsExamples.Common.ImagesPath.Path + "Ocr1.bmp";     string pdfFileName = LeadtoolsExamples.Common.ImagesPath.Path + "Ocr1.pdf";       // Get a DIB     // In this example, we will save the TIF file as BMP, then load it without the BITMAPFILEHEADER structure     // The result is a valid Windows DIB     RasterCodecs.Startup();       using(RasterCodecs codecs = new RasterCodecs())        codecs.Convert(tifFileName, bmpFileName, RasterImageFormat.Bmp, 0, 0, 1, null);       RasterCodecs.Shutdown();       // From MSDN     const int bitmapFileHeaderStructSize = 14;     IntPtr dib = IntPtr.Zero;       using(FileStream fs = File.OpenRead(bmpFileName))     {        // Allocate the DIB        int dibSize = (int)fs.Length - bitmapFileHeaderStructSize;        dib = Marshal.AllocHGlobal(dibSize);        int dibOffset = 0;          // Now read it        fs.Seek(bitmapFileHeaderStructSize, SeekOrigin.Begin);          const int bufferSize = 1024 * 4;        byte[] buffer = new byte[bufferSize];        int bytes = 0;        do        {           bytes = fs.Read(buffer, 0, bufferSize);           if(bytes > 0)           {              IntPtr dibPtr = new IntPtr(dib.ToInt64() + dibOffset);              Marshal.Copy(buffer, 0, dibPtr, bytes);              dibOffset += bytes;           }        }        while(bytes > 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.AddDib(dib, null);             // Free the DIB since we do not need it anymore           Marshal.FreeHGlobal(dib);             // 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 add a device independent bitmap (DIB) stored in an unmanaged memory pointer to the OCR document.

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

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