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This topic applies to FRE for Windows .
This section is intended to help you upgrade your code using ABBYY ScanDifFinder SDK to a new Document Comparison API that is implemented in ABBYY FineReader Engine. ABBYY ScanDifFinder SDK:
  • Uses built-in recognition mechanisms for the documents processing
  • Compares a file with its copy and saves the result as the page images
ABBYY FineReader Engine with the Document Comparison API:
  • Uses a full range of ABBYY FineReader Engine methods to prepare the documents for comparison
  • Requires usage of the documents or pages that were recognized using ABBYY FineReader Engine
  • Compares a document or selected range of pages with their copies and exports the result to an XML or DOCX format
In this release the Document Comparison API does not support: This object will be implemented in future releases.

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Samples

ABBYY ScanDifFinder SDK and Document Comparison API use widely different methods to compare the files. The samples below illustrate this difference. ABBYY ScanDifFinder SDK code sample 
//Specify the paths to the documents to be compared,
//and the path for the comparison result
 
try
{
    string refFile = Path.GetFullPath( args[0] );
    string userFile = Path.GetFullPath( args[1] );
    ScanDifFinder difFinder = new ScanDifFinder();
    difFinder.TempDir = tempDir;
    ProcessFiles( difFinder, refFile, userFile );
}
catch (Exception)
{
}
finally
{
    if (Directory.Exists( tempDir ))
    Directory.Delete( tempDir, true );
}
Document Comparison API sample 
// Perform full processing of reference document
FREngine.FRDocument referenceFRDocument = engine.CreateFRDocument();
referenceFRDocument.AddImageFile( "C:\\ReferenceDocument.pdf", null, null );
referenceFRDocument.Process( dpParams );
// Perform full processing of user document
FREngine.FRDocument userFRDocument = engine.CreateFRDocument();
userFRDocument.AddImageFile( "C:\\UserDocument.pdf", null, null );
userFRDocument.Process( dpParams );
// Perform comparison
FREngine.IComparator comparator = engineLoader.Engine.CreateComparator();
FREngine.IComparisonResult comparisonResult = 
    comparator.CompareDocuments( referenceFRDocument, userFRDocument, null, null );
FREngine.IChanges changes = comparisonResult.Changes;
// Work with the comparison result
foreach (FREngine.IChange change in changes)
{
FREngine.IChangeLocation userLocation = change.UserLocation;
FREngine.IChangePosition userChangeStartPosition = userLocation.StartPosition;
FREngine.IChangePosition userChangeEndPosition = userLocation.EndPosition;
}
// Export the result to a file of the specified format
comparisonResult.Export( "C:\\ComparisonResult.xml", FREngine.ComparatorExportFormatEnum.CEF_Xml, null );

​
API Comparison

The methods and properties of ABBYY FineReader Engine, that replace the methods and properties of ABBYY ScanDifFinder SDK, are described in the table below.

Object/Enumeration of ABBYY ScanDifFinder SDK

Property/Method

Replacing Methods/Properties from ABBYY FineReader Engine

ScanDifFinder Class


Use the Comparator object instead as the main object for documents or pages comparison.

CompareFiles

Use the CompareDocuments method for the document comparison and ComparePages method for the pages comparison.

ImageSettingsForExportedImages

Saving images is performed with ABBYY FineReader Engine methods, for example, with the WriteToFile method of the Image object.

Languages

Use the SetPredefinedTextLanguage method of the RecognizerParams object.

Options

Use the properties of the PrepareImageMode, PageProcessingParams and ObjectsExtractionParams objects instead.

SetLocalLicenseFile

The licensing of the Document Comparison API is performed using ABBYY FineReader Engine (see Licensing).

TempDir

Use the InitializeEngine method to specify the path to the folder for ABBYY FineReader Engine temporary files and other additional parameters.

CompareResult Class


Use the ComparisonResult object instead. To represent the result of comparing the original document or page with its copy, use the GetChangesForReferencePage and GetChangesForUserPage methods. To export the result to a file, use the Export method.

AllChanges

Use the Changes object instead to get the list of all changes that were detected during the document comparison.

RefPagesCount

Use the Count property of the FRPages object to get the number of pages in a document.

UserPagesCount

BaseChange Interface


Use the Change object to represent one difference between the original document and its copy. The GetAsTextChange method will help you to get the change made in the document text.

ChangeType

Use the ChangeType and the ModificationType properties of the Change object instead. These properties return the information about the type of the changed content and the kind of modification that was made.

RefLocation

Use the ReferenceLocation property of the Change object instead.

RefText

Use the ReferenceText property of the TextChange object instead.

UserLocation

Use the UserLocation property of the Change object instead.

UserText

Use the UserText property of the TextChange object instead.

Change Interface


Use the Change object instead to get the information about one change.

Description

This property is removed because the Document Comparison API uses another logical structure.

EditLength

Use the EditLength property of the TextChange object instead.

RefDescription

These properties are removed because the Document Comparison API uses another logical structure.

SmallChanges

UserDescription

ChangeLocation Interface


Use the ChangeLocation object to get information about the location of the change.

GetRelativeChangePosition

Use the RegionForPage property of the ChangeLocation object instead. This property returns the region of the change on the specified page.

PageIndex

ComparisonOptions Class


Use the ComparisonParams object instead.

DoNotUsePdfTextLayer

Use the SourceContentReuseMode property of the ObjectsExtractionParams object, which has been set to CRM_DoNotReuse, instead. This property specifies how to use the text and image layers of the source PDF file.

DoubleColumnsMode

Use the UseDoubleLanguageAgreementMode property of the ComparisonParams object instead.

UseDoubleLanguageAgreementMode is not currently implemented.

EnhanceLocalContrast

Use the EnhanceLocalContrast method of the ImageDocument object.

FastMode

This property is removed because the Document Comparison API uses another logical structure.

IgnoreColorObjects

Use the ProhibitColorObjectsAtProcessing property of the PageProcessingParams object instead. This property specifies if color objects must be filtered out on the image before layout analysis and recognition.

IgnoreOcrErrors

Use the CorrectOcrErrors property of the ComparisonParams object instead.

IgnoreOneLetterNonDigits

Use the DetectOneLetterNonDigitChanges property of the ComparisonParams object instead.

IgnorePunctuators

Use the DetectPunctuatorChanges property of the ComparisonParams object instead.

IgnoreRunningTitles

Use the DetectRunningTitleChanges property of the ComparisonParams object instead.

IgnoreWhiteSpaces

This property was modified and performs another function now (see the DetectWhiteSpaceChanges property of the ComparisonParams object).

ProcessDocumentAsOneLineText

This property is removed because the Document Comparison API uses another logical structure.

ImageSettings Class

ColorType

Saving images is performed with ABBYY FineReader Engine methods, for example, with the WriteToFile method of the Image object.

CompressionType

Extension

Format

Resolution

RecognitionLanguage Class

DisplayName

Use the SetPredefinedTextLanguage method of the RecognizerParams object.

Language

ChangeTypeEnum Enumeration


Use ModificationTypeEnum and DocumentChangeTypeEnum instead. These enumerations specify the kind of modification made to the document content and the type of the changed content.

ColorTypeEnum Enumeration


Saving images is performed with ABBYY FineReader Engine methods, for example, with the WriteToFile method of the Image object.

CompressionTypeEnum Enumeration

FileFormatEnum Enumeration

LanguageEnum Enumeration

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See also

Document Comparison Objects