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AddPage(Stream,OcrProgressCallback) Method

Adds a page from a disk file.
public IOcrPage AddPage( 
   Stream stream, 
   OcrProgressCallback callback 
- (nullable LTOcrPage *)addPageWithStream:(LTLeadStream *)stream  
                                    error:(NSError **)error 
public OcrPage addPage(ILeadStream stream, 
                       OcrProgressListener callback) 
def AddPage(self,stream,callback): 


A .NET stream containing the image.

Optional callback to show operation progress.

Return Value

The IOcrPage object that define the newly added page.


This method will load the first page from a raster image stored inside a .NET stream and adds it to the OCR document.

To add all or specific range of the pages of a multipage image file stored in a .NET stream to the OCR document, use the AddPages(Stream stream, 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.

If you passed a RasterCodecs object to the IOcrEngine.Startup, then this method will use the same RasterCodecs object to load the raster image file. If you did not pass a RasterCodecs object, the engine will create an instance the first time one of the add or export page methods is called.

The image file in  stream can be any of the file formats supported by LEADTOOLS. For more information, refer to Summary of All Supported Image File Formats.

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 loads the image(s) and sets them in the pages internally. 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.


This example will add a raster image stored in a memory stream 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 AddPageFromStreamExample() 
   string tifFileName = Path.Combine(LEAD_VARS.ImagesDir, "Ocr1.tif"); 
   string pdfFileName = Path.Combine(LEAD_VARS.ImagesDir, "Ocr1.pdf"); 
   // Load the TIF image into a memory stream 
   MemoryStream ms = new MemoryStream(); 
   using (FileStream fs = File.OpenRead(tifFileName)) 
      const int bufferSize = 1024 * 4; 
      byte[] buffer = new byte[bufferSize]; 
      int bytes = 0; 
         bytes = fs.Read(buffer, 0, bufferSize); 
         if (bytes > 0) 
            ms.Write(buffer, 0, bytes); 
      while (bytes > 0); 
   // Reset the stream position 
   ms.Position = 0; 
   // Create an instance of the engine 
   using (IOcrEngine ocrEngine = OcrEngineManager.CreateEngine(OcrEngineType.LEAD)) 
      // Start the engine using default parameters 
      ocrEngine.Startup(null, null, null, LEAD_VARS.OcrLEADRuntimeDir); 
      // Create an OCR document 
      using (IOcrDocument ocrDocument = ocrEngine.DocumentManager.CreateDocument()) 
         // Add the image 
         ocrDocument.Pages.AddPage(ms, null); 
         // We do not need the stream 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:\LEADTOOLS23\Resources\Images"; 
   public const string OcrLEADRuntimeDir = @"C:\LEADTOOLS23\Bin\Common\OcrLEADRuntime"; 
import java.io.File; 
import java.io.IOException; 
import java.net.URI; 
import java.net.URISyntaxException; 
import org.junit.*; 
import org.junit.runner.JUnitCore; 
import org.junit.runner.Result; 
import org.junit.runner.notification.Failure; 
import static org.junit.Assert.*; 
import leadtools.*; 
import leadtools.codecs.*; 
import leadtools.document.writer.DocumentFormat; 
import leadtools.imageprocessing.core.DeskewCommand; 
import leadtools.imageprocessing.core.DeskewCommandFlags; 
import leadtools.ocr.OcrDocument; 
import leadtools.ocr.OcrEngine; 
import leadtools.ocr.OcrEngineManager; 
import leadtools.ocr.OcrEngineType; 
public void IOcrPageCollectionsAddPageFromStreamExample() throws IOException { 
   final String LEAD_VARS_IMAGES_DIR = "C:\\LEADTOOLS23\\Resources\\Images"; 
   final String LEAD_VARS_OCR_LEAD_RUNTIME_DIR = "C:\\LEADTOOLS23\\Bin\\Common\\OcrLEADRuntime"; 
   String tifFileName = combine(LEAD_VARS_IMAGES_DIR, "ocr1-4.tif"); 
   String pdfFileName = combine(LEAD_VARS_IMAGES_DIR, "ocr1-4.pdf"); 
   // Create an instance of the engine 
   OcrEngine ocrEngine = OcrEngineManager.createEngine(OcrEngineType.LEAD); 
   // Start the engine using default parameters 
   ocrEngine.startup(null, null, null, LEAD_VARS_OCR_LEAD_RUNTIME_DIR); 
   assertTrue("Engine unsuccessfully started", ocrEngine.isStarted()); 
   // Create an OCR document 
   OcrDocument ocrDocument = ocrEngine.getDocumentManager().createDocument(); 
   // Load the TIF image into a memory stream 
   ILeadStream file = LeadStreamFactory.create(tifFileName); 
   // Add the image 
   ocrDocument.getPages().addPages(file, 1, 4, null); 
   // Recognize 
   // Save 
   ocrDocument.save(pdfFileName, DocumentFormat.PDF, null); 
   assertTrue("File unsuccessfully saved", (new File(tifFileName)).exists()); 
   ocrDocument = null; 
   // Shutdown the engine 
   // Note: calling Dispose will also automatically shutdown the engine if it has 
   // been started 

Target Platforms

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Leadtools.Ocr Assembly

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