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AddPage(RasterImage,OcrProgressCallback) Method

Summary

Adds a page from a RasterImage object.

Syntax

C#
VB
Java
Objective-C
C++

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

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

public OcrPage addPage(RasterImage image, 
                       OcrProgressListener 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 LEADTOOLS OCR Module - LEAD 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#
VB
using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.Ocr; 
using Leadtools.Document.Writer; 
using Leadtools.Forms.Common; 
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.LEAD, 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.OcrLEADRuntimeDir); 
 
      // 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 OcrLEADRuntimeDir = @"C:\LEADTOOLS 20\Bin\Common\OcrLEADRuntime"; 
} 

Imports Leadtools 
Imports Leadtools.Codecs 
Imports Leadtools.Ocr 
Imports Leadtools.Document.Writer 
Imports Leadtools.Forms 
Imports Leadtools.ImageProcessing.Core 
 
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.LEAD, 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.OcrLEADRuntimeDir) 
 
      ' 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 OcrLEADRuntimeDir As String = "C:\LEADTOOLS 20\Bin\Common\OcrLEADRuntime" 
End Class 

Requirements

Target Platforms

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Leadtools.Ocr Assembly