AddPage(RasterImage,OcrProgressCallback) Method

Adds a page from a Leadtools.RasterImage object.

Syntax

Visual Basic
C#
WinRT C#
WinRT JavaScript
C++

IOcrPage AddPage( 
   RasterImage image,
   OcrProgressCallback callback
)

'Declaration
 
Overloads Function AddPage( _
   ByVal image As RasterImage, _
   ByVal callback As OcrProgressCallback _
) As IOcrPage

'Usage
 
Dim instance As IOcrPageCollection
Dim image As RasterImage
Dim callback As OcrProgressCallback
Dim value As IOcrPage
 
value = instance.AddPage(image, callback)

IOcrPage AddPage( 
   RasterImage image,
   OcrProgressCallback callback
)

function Leadtools.Forms.Ocr.IOcrPageCollection.AddPage(RasterImage,OcrProgressCallback)( 
   image ,
   callback 
)

IOcrPage^ AddPage( 
   RasterImage^ image,
   OcrProgressCallback^ callback
)

Parameters

image: The Leadtools.RasterImage object containing the page to add.
callback: Optional callback to show operation progress.

Return Value

The IOcrPage object that define the newly added page.

Remarks

This method copies the Leadtools.RasterImage object image data into the newly created IOcrPage. Therefore, after this method returns there is no relationship between image and the IOcrPage inside the OCR document. For example, if you do not need the image object after calling this method, you should dispose it after this method returns.

This method guarantees that no changes will be made to image.

If image contains more than one page, then the current page as defined in RasterImage.Page is the one added to the OCR document.

To add all or specific range of the pages of a multi-page Leadtools.RasterImage object to the OCR document, either iterate through the pages by changing to the value of RasterImage.Page to go from 1 to RasterImage.PageCount or use the AddPages(RasterImage image, 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.

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.

Example

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

Copy Code

Public Sub AddPageOcrExample()
      ' For this example, we will use the Clean.tif image. This image is skewed so we will do that using the
      ' LEADTOOLS Deskew command before we add it to the document
      Dim tifFileName As String = Path.Combine(LEAD_VARS.ImagesDir, "Clean.tif")
      Dim pdfFileName As String = Path.Combine(LEAD_VARS.ImagesDir, "Clean.pdf")
      ' Load the TIF file
      Dim codecs As New RasterCodecs()

      Dim image As RasterImage = codecs.Load(tifFileName)

      ' Check if the image needs to be deskewed
      Dim deskewCommand As New DeskewCommand()
      deskewCommand.FillColor = RasterColor.FromKnownColor(RasterKnownColor.White)
      deskewCommand.Flags = DeskewCommandFlags.ReturnAngleOnly
      deskewCommand.Run(image)

      If (deskewCommand.Angle <> 0) Then
         ' Deskew it
         deskewCommand.Flags = DeskewCommandFlags.RotateLinear
         deskewCommand.Run(image)
      End If

      ' Create an instance of the engine
      Using ocrEngine As IOcrEngine = OcrEngineManager.CreateEngine(OcrEngineType.Plus, False)
         ' Start the engine using default parameters
         ' Since we have a RasterCodecs object, re-use it in the OCR engine. Although
         ' this demo will not use it, it is always a good practice
         ocrEngine.Startup(codecs, Nothing, Nothing, Nothing)

         ' Create an OCR document
         Using ocrDocument As IOcrDocument = ocrEngine.DocumentManager.CreateDocument()
            ' Add the image
            ocrDocument.Pages.AddPage(image, Nothing)

            ' We do not need the image anymore
            image.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

      codecs.Dispose()
   End Sub

Public NotInheritable Class LEAD_VARS
   Public Const ImagesDir As String = "C:\Users\Public\Documents\LEADTOOLS Images"
End Class

public void AddPageOcrExample()
   {
      // For this example, we will use the Clean.tif image. This image is skewed so we will do that using the
      // LEADTOOLS Deskew command before we add it to the document
      string tifFileName = Path.Combine(LEAD_VARS.ImagesDir, "Clean.tif");
      string pdfFileName = Path.Combine(LEAD_VARS.ImagesDir, "Clean.pdf");
      // Load the TIF file
      RasterCodecs codecs = new RasterCodecs();

      RasterImage image = codecs.Load(tifFileName);

      // Check if the image needs to be deskewed
      DeskewCommand deskewCommand = new DeskewCommand();
      deskewCommand.FillColor = RasterColor.FromKnownColor(RasterKnownColor.White);
      deskewCommand.Flags = DeskewCommandFlags.ReturnAngleOnly;
      deskewCommand.Run(image);

      if(deskewCommand.Angle != 0)
      {
         // Deskew it
         deskewCommand.Flags = DeskewCommandFlags.RotateLinear;
         deskewCommand.Run(image);
      }

      // Create an instance of the engine
      using(IOcrEngine ocrEngine = OcrEngineManager.CreateEngine(OcrEngineType.Plus, false))
      {
         // Start the engine using default parameters
         // Since we have a RasterCodecs object, re-use it in the OCR engine. Although
         // this demo will not use it, it is always a good practice
         ocrEngine.Startup(codecs, null, null, null);

         // Create an OCR document
         using(IOcrDocument ocrDocument = ocrEngine.DocumentManager.CreateDocument())
         {
            // Add the image
            ocrDocument.Pages.AddPage(image, null);

            // We do not need the image anymore
            image.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();
      }

      codecs.Dispose();
   }

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

[TestMethod]
public async Task AddPageOcrExample()
{
   // For this example, we will use the Clean.tif image. This image is skewed so we will do that using the
   // LEADTOOLS Deskew command before we add it to the document
   string tifFileName = @"Assets\Clean.tif";
   string pdfFileName = "Clean.pdf";
   // Load the TIF file
   RasterCodecs codecs = new RasterCodecs();

   StorageFile loadFile = await Tools.AppInstallFolder.GetFileAsync(tifFileName);
   RasterImage image = await codecs.LoadAsync(LeadStreamFactory.Create(loadFile));

   // Check if the image needs to be deskewed
   DeskewCommand deskewCommand = new DeskewCommand();
   deskewCommand.FillColor = RasterColorHelper.FromKnownColor(RasterKnownColor.White);
   deskewCommand.Flags = DeskewCommandFlags.ReturnAngleOnly;
   deskewCommand.Run(image);

   if(deskewCommand.Angle != 0)
   {
      // Deskew it
      deskewCommand.Flags = DeskewCommandFlags.RotateLinear;
      deskewCommand.Run(image);
   }

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

   // Start the engine using default parameters
   // Since we have a RasterCodecs object, re-use it in the OCR engine. Although
   // this demo will not use it, it is always a good practice
   ocrEngine.Startup(codecs, null, String.Empty, Tools.OcrEnginePath);

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

   // Add the image
   ocrDocument.Pages.AddPage(image, null);

   // We do not need the image anymore
   image.Dispose();

   // Recognize
   ocrDocument.Pages.Recognize(null);

   // Save
   StorageFile saveFile = await Tools.AppLocalFolder.CreateFileAsync(pdfFileName, CreationCollisionOption.ReplaceExisting);
   await ocrDocument.SaveAsync(LeadStreamFactory.Create(saveFile), DocumentFormat.Pdf, null);

   // Shutdown the engine
   ocrEngine.Shutdown();

   codecs.Dispose();
}

Requirements

Target Platforms: Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

Reference

IOcrPageCollection Interface
IOcrPageCollection Members
Overload List
OcrEngineManager Class
OcrEngineType Enumeration
IOcrPage Interface
Programming with the LEADTOOLS .NET OCR