AddPage(RasterImage,OcrProgressCallback) Method

Adds a page from a RasterImage object.

Syntax

C#
Visual Basic
WinRT C#
Java
Objective-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
)

- (nullable LTOcrPage *)addPageWithImage:(LTRasterImage *)image 
                                   error:(NSError **)error

public OcrPage addPage(RasterImage image,
                       OcrProgressListener callback)

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

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

Parameters

image: The 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 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 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: If the value of the "Recognition.ShareOriginalImage" (only supported by the Advantage OCR engine) setting is supported and is set to true, then calling this method will store the reference image inside the page and the image reference must be kept alive as long as the IOcrPage is alive. In this mode, the original image reference can be obtained from the page using IOcrPage.GetRasterImage(OcrPageType.Original). Sharing the original image minimizes the memory used during OCR operations.

This member only works with memory-based documents and will throw an exception otherwise. For more information, refer to IOcrDocumentManager.CreateDocument and Programming with the LEADTOOLS .NET OCR.

Example

This example will load a RasterImage object, perform image cleanup on it using LEADTOOLS then add it to an OCR document

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.ImageProcessing.Core

<TestMethod>
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.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, Nothing, Nothing, LEAD_VARS.OcrAdvantageRuntimeDir)

      ' 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"
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.ImageProcessing.Core;

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.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, null, LEAD_VARS.OcrAdvantageRuntimeDir);

      // 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";
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;
using Leadtools.ImageProcessing.Core;

      
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

Reference

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