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AddPages(RasterImage,int,int,OcrProgressCallback) Method

Summary

Adds one or more pages from a multi-page RasterImage object.

Syntax

C#
VB
Java
Objective-C
C++

Overloads Sub AddPages( _ 
   ByVal image As RasterImage, _ 
   ByVal imageFirstPageNumber As Integer, _ 
   ByVal imageLastPageNumber As Integer, _ 
   ByVal callback As OcrProgressCallback _ 
)  

- (BOOL)addPagesWithImage:(LTRasterImage *)image  
                  inRange:(NSRange)range  
                    error:(NSError **)error 

public void addPages(RasterImage image, 
                     int imageFirstPageNumber, 
                     int imageLastPageNumber, 
                     OcrProgressListener callback) 

Parameters

image
The RasterImage object containing the pages to add.

imageFirstPageNumber
1-based index of the first page in image to add.

imageLastPageNumber
1-based index of the last page in image to add. A value of -1 means add up to and including the last page in image.

callback
Optional callback to show operation progress.

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.

A short-cut to add all the pages of a RasterImage object to the OCR document is AddPages(image, 1, -1, callback).

To add a single page from a RasterImage object, you can use AddPage(RasterImage image, OcrProgressCallback callback).

This method will add the page(s) 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 value of the "Recognition.ShareOriginalImage" (only supported by the LEADTOOLS OCR Module - LEAD Engine) setting is not used when calling this method. The engine will make a copy of image and store it in the page. Calling IOcrPage.GetRasterImage(OcrPageType.Original) on the page will return a null reference.

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 multiple pages into a RasterImage object then add them to the OCR engine.

C#
VB
using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.Ocr; 
using Leadtools.Document.Writer; 
using Leadtools.Forms.Common; 
using Leadtools.ImageProcessing.Core; 
 
public void AddMultiPageRasterImageExample() 
{ 
   string pdfFileName = Path.Combine(LEAD_VARS.ImagesDir, "Ocr1.pdf"); 
 
   // Load the Ocr1.tif, Ocr2.tif, Ocr3.tif and Ocr4.tif to a single RasterImage object 
   RasterCodecs codecs = new RasterCodecs(); 
 
   RasterImage image = null; 
   for (int i = 0; i < 4; i++) 
   { 
      string pageFileName = Path.Combine(LEAD_VARS.ImagesDir, string.Format("Ocr{0}.tif", i + 1)); 
      RasterImage tempImage = codecs.Load(pageFileName); 
      if (image == null) 
         image = tempImage; 
      else 
         image.AddPage(tempImage); 
   } 
 
   Console.WriteLine("RasterImage has {0} pages", image.PageCount); 
 
   // Create an instance of the engine 
   using (IOcrEngine ocrEngine = OcrEngineManager.CreateEngine(OcrEngineType.LEAD, false)) 
   { 
      // 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 2nd and 3rd pages to the document 
         Console.WriteLine("Adding the pages from 2 to 3 to the document"); 
         ocrDocument.Pages.AddPages(image, 2, 3, null); 
         Console.WriteLine("Document has {0} pages", ocrDocument.Pages.Count); 
 
         // 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 AddMultiPageRasterImageExample() 
   Dim pdfFileName As String = Path.Combine(LEAD_VARS.ImagesDir, "Ocr1.pdf") 
 
   ' Load the Ocr1.tif, Ocr2.tif, Ocr3.tif and Ocr4.tif to a single RasterImage object 
   Dim codecs As New RasterCodecs() 
 
   Dim image As RasterImage = Nothing 
   For i As Integer = 0 To 3 
      Dim pageFileName As String = Path.Combine(LEAD_VARS.ImagesDir, String.Format("Ocr{0}.tif", i + 1)) 
      Dim tempImage As RasterImage = codecs.Load(pageFileName) 
      If image Is Nothing Then 
         image = tempImage 
      Else 
         image.AddPage(tempImage) 
      End If 
   Next 
 
   Console.WriteLine("RasterImage has {0} pages", image.PageCount) 
 
   ' Create an instance of the engine 
   Using ocrEngine As IOcrEngine = OcrEngineManager.CreateEngine(OcrEngineType.LEAD, False) 
      ' 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 2nd and 3rd pages to the document 
         Console.WriteLine("Adding the pages from 2 to 3 to the document") 
         ocrDocument.Pages.AddPages(image, 2, 3, Nothing) 
         Console.WriteLine("Document has {0} pages", ocrDocument.Pages.Count) 
 
         ' 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