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AddPages(RasterImage,int,int,OcrProgressCallback) Method

Adds one or more pages from a multipage RasterImage object.
- (BOOL)addPagesWithImage:(LTRasterImage *)image  
                    error:(NSError **)error 
public void addPages(RasterImage image, 
                     int imageFirstPageNumber, 
                     int imageLastPageNumber, 
                     OcrProgressListener callback) 


The RasterImage object containing the pages to add.

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

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.

Optional callback to show operation progress.


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.


This example will load multiple pages into a RasterImage object then add them to the OCR engine.

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; 
   Console.WriteLine("RasterImage has {0} pages", image.PageCount); 
   // Create an instance of the engine 
   using (IOcrEngine ocrEngine = OcrEngineManager.CreateEngine(OcrEngineType.LEAD)) 
      // 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 
         // Recognize 
         // Save 
         ocrDocument.Save(pdfFileName, DocumentFormat.Pdf, null); 
      // Shutdown the engine 
      // Note: calling Dispose will also automatically shutdown the engine if it has been started 
static class LEAD_VARS 
   public const string ImagesDir = @"C:\LEADTOOLS22\Resources\Images"; 
   public const string OcrLEADRuntimeDir = @"C:\LEADTOOLS22\Bin\Common\OcrLEADRuntime"; 

Target Platforms

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Leadtools.Ocr Assembly

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© 1991-2023 LEAD Technologies, Inc. All Rights Reserved.