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InsertPage(int,RasterImage,OcrProgressCallback) Method

Summary

Inserts a RasterImage object to the specified location.

Syntax

C#
VB
Java
Objective-C
C++

Overloads Function InsertPage( _ 
   ByVal pageIndex As Integer, _ 
   ByVal image As RasterImage, _ 
   ByVal callback As OcrProgressCallback _ 
) As IOcrPage 

- (nullable LTOcrPage *)insertPageAtIndex:(NSUInteger)pageIndex 
                                    image:(LTRasterImage *)image 
                                    error:(NSError **)error 

public OcrPage insertPage(int pageIndex, 
                          RasterImage image, 
                          OcrProgressListener callback) 

Parameters

pageIndex
The zero-based index at which image should be inserted.

image
The RasterImage object containing the page to insert.

callback
Optional callback to show operation progress.

Return Value

The IOcrPage object that define the newly inserted 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 inserted to the OCR document.

To insert 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 InsertPages(int pageIndex, RasterImage image, int imageFirstPageNumber, int imageLastPageNumber, OcrProgressCallback callback) method.

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 then insert in reverse order a group of RasterImage objects.

C#
VB
using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.Ocr; 
using Leadtools.Document.Writer; 
using Leadtools.Forms.Common; 
using Leadtools.ImageProcessing.Core; 
 
public void InsertPageFromRasterImageExample() 
{ 
   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(); 
 
   // 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()) 
      { 
         // Loop through the images, insert them in the reverse order 
         for (int i = 0; i < 4; i++) 
         { 
            string pageFileName = Path.Combine(LEAD_VARS.ImagesDir, string.Format("Ocr{0}.tif", i + 1)); 
            using (RasterImage image = codecs.Load(pageFileName)) 
               ocrDocument.Pages.InsertPage(0, image, null); 
         } 
 
         // 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 InsertPageFromRasterImageExample() 
   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() 
 
   ' 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() 
         ' Loop through the images, insert them in the reverse order 
         For i As Integer = 0 To 3 
            Dim pageFileName As String = Path.Combine(LEAD_VARS.ImagesDir, String.Format("Ocr{0}.tif", i + 1)) 
            Using image As RasterImage = codecs.Load(pageFileName) 
               ocrDocument.Pages.InsertPage(0, image, Nothing) 
            End Using 
         Next 
 
         ' 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