# ABBYY FineReader Engine — API Reference: Supporting Objects

> Classification, mechanism, document comparison, batch processor, license-related objects, engine loaders, functions, and top-level API reference stubs for the FineReader Engine 12 C++ SDK.
> For the full ABBYY documentation index, see: https://docs.abbyy.com/llms.txt
> Other API Reference section files:
>   Data Types: https://docs.abbyy.com/llms-finereader-api-datatypes.txt
>   Document and Image Objects: https://docs.abbyy.com/llms-finereader-api-documents.txt
>   Engine and Layout Objects: https://docs.abbyy.com/llms-finereader-api-engine.txt
> Guides (installation, licensing, tour): https://docs.abbyy.com/llms-finereader-guide.txt

## API Reference Top-Level Pages

- [API Reference](https://docs.abbyy.com/fine-reader/engine/api-reference.md): Reference for the ABBYY FineReader Engine 12 API: objects, interfaces, methods, and parameters for OCR, layout analysis, and document export.
- [Alphabetical List of the ABBYY FineReader Engine 12 Objects and Interfaces](https://docs.abbyy.com/fine-reader/engine/api-reference/alphabetical-list-of-objects-and-interfaces.md): Alphabetical List of the ABBYY FineReader Engine 12 Objects and Interfaces in the ABBYY FineReader Engine API — The ABBYY FineReader Engine functionality is implemented in a number of objects that provide methods for...
- [Object Diagrams](https://docs.abbyy.com/fine-reader/engine/api-reference/object-diagram.md): Object Diagrams in the ABBYY FineReader Engine API — This topic contains the Object diagrams for Linux, macOS, and Windows.

## Classification-Related Objects

- [Classification-Related Objects](https://docs.abbyy.com/fine-reader/engine/api-reference/classification-related-objects.md): Classification-Related Objects in the ABBYY FineReader Engine API — ClassificationEngine, Trainer, Model, ClassificationResults, Categories, and related objects used to train and apply document classification.
- [Categories Object (ICategories Interface)](https://docs.abbyy.com/fine-reader/engine/api-reference/classification-related-objects/categories.md): Categories object (ICategories interface) in the ABBYY FineReader Engine API — a collection of Category objects used to populate the categorized data set for training a classifier.
- [AddNew Method of the Categories Object](https://docs.abbyy.com/fine-reader/engine/api-reference/classification-related-objects/categories/addnew-method.md): AddNew method of the Categories object in the ABBYY FineReader Engine API — creates a new category with the specified label and adds it to the collection.
- [DeleteAll Method](https://docs.abbyy.com/fine-reader/engine/api-reference/classification-related-objects/categories/deleteall-method.md): DeleteAll method in the ABBYY FineReader Engine API — common method that removes all elements from a FineReader Engine collection.
- [DeleteAt Method](https://docs.abbyy.com/fine-reader/engine/api-reference/classification-related-objects/categories/deleteat-method.md): DeleteAt method in the ABBYY FineReader Engine API — common method that removes an element from a FineReader Engine collection by index.
- [Element Property](https://docs.abbyy.com/fine-reader/engine/api-reference/classification-related-objects/categories/element-property.md): Element property in the ABBYY FineReader Engine API — common property that provides access to a single element of a FineReader Engine collection.
- [Find Method of the Categories Object](https://docs.abbyy.com/fine-reader/engine/api-reference/classification-related-objects/categories/find-method.md): Find method of the Categories object in the ABBYY FineReader Engine API — finds a category in the collection by its label.
- [Item Method](https://docs.abbyy.com/fine-reader/engine/api-reference/classification-related-objects/categories/item-method.md): Item method in the ABBYY FineReader Engine API — common method that provides access to a single element of a FineReader Engine collection.
- [Category Object (ICategory Interface)](https://docs.abbyy.com/fine-reader/engine/api-reference/classification-related-objects/category.md): Category object (ICategory interface) in the ABBYY FineReader Engine API — a set of classification objects that belong to the same category, used as part of the training data.
- [ClassificationEngine Object (IClassificationEngine Interface)](https://docs.abbyy.com/fine-reader/engine/api-reference/classification-related-objects/classificationengine.md): ClassificationEngine object (IClassificationEngine interface) in the ABBYY FineReader Engine API — main entry point to the Classification API; loads classification models and creates trainers and classification objects.
- [CreateModelFromFile Method of the ClassificationEngine Object](https://docs.abbyy.com/fine-reader/engine/api-reference/classification-related-objects/classificationengine/createmodelfromfile-method.md): CreateModelFromFile method of the ClassificationEngine object in the ABBYY FineReader Engine API — loads a classification model from a file on disk.
- [CreateObjectFromDocument Method of the ClassificationEngine Object](https://docs.abbyy.com/fine-reader/engine/api-reference/classification-related-objects/classificationengine/createobjectfromdocument-method.md): CreateObjectFromDocument method of the ClassificationEngine object in the ABBYY FineReader Engine API — creates a new ClassificationObject from the first page of an FRDocument.
- [CreateObjectFromPage Method of the ClassificationEngine Object](https://docs.abbyy.com/fine-reader/engine/api-reference/classification-related-objects/classificationengine/createobjectfrompage-method.md): CreateObjectFromPage method of the ClassificationEngine object in the ABBYY FineReader Engine API — creates a new ClassificationObject from a single FRPage.
- [CreateTrainer Method of the ClassificationEngine Object](https://docs.abbyy.com/fine-reader/engine/api-reference/classification-related-objects/classificationengine/createtrainer-method.md): CreateTrainer method of the ClassificationEngine object in the ABBYY FineReader Engine API — creates a Trainer object used to configure parameters and train a new classification model.
- [CreateTrainingData Method of the ClassificationEngine Object](https://docs.abbyy.com/fine-reader/engine/api-reference/classification-related-objects/classificationengine/createtrainingdata-method.md): CreateTrainingData method of the ClassificationEngine object in the ABBYY FineReader Engine API — creates a new empty TrainingData object.
- [ClassificationObject Object (IClassificationObject Interface)](https://docs.abbyy.com/fine-reader/engine/api-reference/classification-related-objects/classificationobject.md): ClassificationObject object (IClassificationObject interface) in the ABBYY FineReader Engine API — holds classification-relevant data extracted from a document or page for training or classification.
- [ClassificationObjects Object (IClassificationObjects Interface)](https://docs.abbyy.com/fine-reader/engine/api-reference/classification-related-objects/classificationobjects.md): ClassificationObjects object (IClassificationObjects interface) in the ABBYY FineReader Engine API — a collection of ClassificationObject items used to group classification-relevant data.
- [Add Method](https://docs.abbyy.com/fine-reader/engine/api-reference/classification-related-objects/classificationobjects/add-method.md): Add method in the ABBYY FineReader Engine API — common method that adds an existing object at the end of a FineReader Engine collection.
- [DeleteAll Method](https://docs.abbyy.com/fine-reader/engine/api-reference/classification-related-objects/classificationobjects/deleteall-method.md): DeleteAll method in the ABBYY FineReader Engine API — common method that removes all elements from a FineReader Engine collection.
- [DeleteAt Method](https://docs.abbyy.com/fine-reader/engine/api-reference/classification-related-objects/classificationobjects/deleteat-method.md): DeleteAt method in the ABBYY FineReader Engine API — common method that removes an element from a FineReader Engine collection by index.
- [Element Property](https://docs.abbyy.com/fine-reader/engine/api-reference/classification-related-objects/classificationobjects/element-property.md): Element property in the ABBYY FineReader Engine API — common property that provides access to a single element of a FineReader Engine collection.
- [Find Method of the ClassificationObjects Object](https://docs.abbyy.com/fine-reader/engine/api-reference/classification-related-objects/classificationobjects/find-method.md): Find method of the ClassificationObjects object in the ABBYY FineReader Engine API — finds a classification object in the collection by its description.
- [Item Method](https://docs.abbyy.com/fine-reader/engine/api-reference/classification-related-objects/classificationobjects/item-method.md): Item method in the ABBYY FineReader Engine API — common method that provides access to a single element of a FineReader Engine collection.
- [ClassificationResult Object (IClassificationResult Interface)](https://docs.abbyy.com/fine-reader/engine/api-reference/classification-related-objects/classificationresult.md): ClassificationResult object (IClassificationResult interface) in the ABBYY FineReader Engine API — a single classification result with the category label and the probability that the classified object belongs to it.
- [ClassificationResults Object (IClassificationResults Interface)](https://docs.abbyy.com/fine-reader/engine/api-reference/classification-related-objects/classificationresults.md): ClassificationResults object (IClassificationResults interface) in the ABBYY FineReader Engine API — a collection of ClassificationResult items returned by classification methods, sorted by probability.
- [Element Property](https://docs.abbyy.com/fine-reader/engine/api-reference/classification-related-objects/classificationresults/element-property.md): Element property in the ABBYY FineReader Engine API — common property that provides access to a single element of a FineReader Engine collection.
- [Item Method](https://docs.abbyy.com/fine-reader/engine/api-reference/classification-related-objects/classificationresults/item-method.md): Item method in the ABBYY FineReader Engine API — common method that provides access to a single element of a FineReader Engine collection.
- [ConfusionMatrix Object (IConfusionMatrix Interface)](https://docs.abbyy.com/fine-reader/engine/api-reference/classification-related-objects/confusionmatrix.md): ConfusionMatrix object (IConfusionMatrix interface) in the ABBYY FineReader Engine API — the confusion matrix for a classification model, showing how objects from each category were classified.
- [Element Property of the ConfusionMatrix Object](https://docs.abbyy.com/fine-reader/engine/api-reference/classification-related-objects/confusionmatrix/element-property.md): Element property of the ConfusionMatrix object in the ABBYY FineReader Engine API — returns the value of the selected cell in the confusion matrix.
- [Model Object (IModel Interface)](https://docs.abbyy.com/fine-reader/engine/api-reference/classification-related-objects/model.md): Model object (IModel interface) in the ABBYY FineReader Engine API — a trained classification model used to classify documents and pages.
- [Classify Method of the Model Object](https://docs.abbyy.com/fine-reader/engine/api-reference/classification-related-objects/model/classify-method.md): Classify method of the Model object in the ABBYY FineReader Engine API — uses the model to classify a given ClassificationObject and returns category-label / probability pairs.
- [SaveToFile Method of the Model Object](https://docs.abbyy.com/fine-reader/engine/api-reference/classification-related-objects/model/savetofile-method.md): SaveToFile method of the Model object in the ABBYY FineReader Engine API — saves a trained classification model to a file on disk.
- [Trainer Object (ITrainer Interface)](https://docs.abbyy.com/fine-reader/engine/api-reference/classification-related-objects/trainer.md): Trainer object (ITrainer interface) in the ABBYY FineReader Engine API — trains a classifier on a categorized data set using configurable TrainingParams and ValidationParams.
- [TrainModel Method of the Trainer Object](https://docs.abbyy.com/fine-reader/engine/api-reference/classification-related-objects/trainer/trainmodel-method.md): TrainModel method of the Trainer object in the ABBYY FineReader Engine API — trains the classifier on the supplied TrainingData using the configured TrainingParams and ValidationParams.
- [TrainingData Object (ITrainingData Interface)](https://docs.abbyy.com/fine-reader/engine/api-reference/classification-related-objects/trainingdata.md): TrainingData object (ITrainingData interface) in the ABBYY FineReader Engine API — a categorized data set used as input for training a classifier.
- [LoadFromFile Method](https://docs.abbyy.com/fine-reader/engine/api-reference/classification-related-objects/trainingdata/loadfromfile-method.md): LoadFromFile method in the ABBYY FineReader Engine API — common method that restores an object's contents from a file on disk.
- [SaveToFile Method](https://docs.abbyy.com/fine-reader/engine/api-reference/classification-related-objects/trainingdata/savetofile-method.md): SaveToFile method in the ABBYY FineReader Engine API — common method that saves an object's contents to a file on disk.
- [TrainingParams Object (ITrainingParams Interface)](https://docs.abbyy.com/fine-reader/engine/api-reference/classification-related-objects/trainingparams.md): TrainingParams object (ITrainingParams interface) in the ABBYY FineReader Engine API — the parameters used when training a classification model, including the classifier type and training mode.
- [TrainingResult Object (ITrainingResult Interface)](https://docs.abbyy.com/fine-reader/engine/api-reference/classification-related-objects/trainingresult.md): TrainingResult object (ITrainingResult interface) in the ABBYY FineReader Engine API — the result of training the classifier on the input data set; includes the trained Model and the ValidationResult.
- [TrainingResults Object (ITrainingResults Interface)](https://docs.abbyy.com/fine-reader/engine/api-reference/classification-related-objects/trainingresults.md): TrainingResults object (ITrainingResults interface) in the ABBYY FineReader Engine API — a collection of TrainingResult items returned by the classification model training methods.
- [Element Property](https://docs.abbyy.com/fine-reader/engine/api-reference/classification-related-objects/trainingresults/element-property.md): Element property in the ABBYY FineReader Engine API — common property that provides access to a single element of a FineReader Engine collection.
- [Item Method](https://docs.abbyy.com/fine-reader/engine/api-reference/classification-related-objects/trainingresults/item-method.md): Item method in the ABBYY FineReader Engine API — common method that provides access to a single element of a FineReader Engine collection.
- [ValidationParams Object (IValidationParams Interface)](https://docs.abbyy.com/fine-reader/engine/api-reference/classification-related-objects/validationparams.md): ValidationParams object (IValidationParams interface) in the ABBYY FineReader Engine API — parameters that control classification-model validation, including k-fold cross-validation settings.
- [ValidationResult Object (IValidationResult Interface)](https://docs.abbyy.com/fine-reader/engine/api-reference/classification-related-objects/validationresult.md): ValidationResult object (IValidationResult interface) in the ABBYY FineReader Engine API — detailed classification-model performance metrics: accuracy, precision, recall, F-measure, and the confusion matrix.

## Mechanism Objects

- [Mechanism Objects](https://docs.abbyy.com/fine-reader/engine/api-reference/mechanism-objects.md): Mechanism Objects in the ABBYY FineReader Engine API — For Linux and macOS, this section contains only one object: ExportFileWriter.
- [ExportFileWriter Object (IExportFileWriter Interface)](https://docs.abbyy.com/fine-reader/engine/api-reference/mechanism-objects/exportfilewriter.md): ExportFileWriter object (IExportFileWriter interface) in the ABBYY FineReader Engine API — This object provides functionality for the export of the recognized information into PDF files.
- [AddPage Method of the ExportFileWriter Object](https://docs.abbyy.com/fine-reader/engine/api-reference/mechanism-objects/exportfilewriter/addpage-method.md): AddPage method of the ExportFileWriter Object in the ABBYY FineReader Engine API — This method saves recognized text from a single page into a file in PDF format.
- [AddPages Method of the ExportFileWriter Object](https://docs.abbyy.com/fine-reader/engine/api-reference/mechanism-objects/exportfilewriter/addpages-method.md): AddPages method of the ExportFileWriter Object in the ABBYY FineReader Engine API — This method saves recognized text from a set of pages into a file in PDF format.
- [Close Method of the ExportFileWriter Object](https://docs.abbyy.com/fine-reader/engine/api-reference/mechanism-objects/exportfilewriter/close-method.md): Close method of the ExportFileWriter Object in the ABBYY FineReader Engine API — This method finalizes the file that was exported to PDF format with AddPage or AddPages methods of the ExportFileWriter object.
- [IScanCallback Interface](https://docs.abbyy.com/fine-reader/engine/api-reference/mechanism-objects/iscancallback.md): IScanCallback interface in the ABBYY FineReader Engine API — This is a callback interface that is used for managing scanning operations.
- [OnError Method of the IScanCallback Interface](https://docs.abbyy.com/fine-reader/engine/api-reference/mechanism-objects/iscancallback/onerror-method.md): OnError method of the IScanCallback Interface in the ABBYY FineReader Engine API — This method is implemented on the client-side.
- [OnImageScanned Method of the IScanCallback Interface](https://docs.abbyy.com/fine-reader/engine/api-reference/mechanism-objects/iscancallback/onimagescanned-method.md): OnImageScanned method of the IScanCallback Interface in the ABBYY FineReader Engine API — This method is implemented on the client-side.
- [OnScanComplete Method of the IScanCallback Interface](https://docs.abbyy.com/fine-reader/engine/api-reference/mechanism-objects/iscancallback/onscancomplete-method.md): OnScanComplete method of the IScanCallback Interface in the ABBYY FineReader Engine API — This method notifies the client that the scanning operation is completed.
- [ScanManager Object (IScanManager Interface)](https://docs.abbyy.com/fine-reader/engine/api-reference/mechanism-objects/scanmanager.md): ScanManager object (IScanManager interface) in the ABBYY FineReader Engine API — This object exposes a set of properties and methods required to perform scanning.
- [FindScanSources Method of the ScanManager Object](https://docs.abbyy.com/fine-reader/engine/api-reference/mechanism-objects/scanmanager/findscansources-method.md): FindScanSources method of the ScanManager Object in the ABBYY FineReader Engine API — This method enables you to receive a list of available scanning sources filtered by user interface type and API type that the scanner...
- [PumpMessages Method of the ScanManager Object](https://docs.abbyy.com/fine-reader/engine/api-reference/mechanism-objects/scanmanager/pumpmessages-method.md): PumpMessages method of the ScanManager Object in the ABBYY FineReader Engine API — This method pumps queued messages.
- [ScanSource Object (IScanSource Interface)](https://docs.abbyy.com/fine-reader/engine/api-reference/mechanism-objects/scansource.md): ScanSource object (IScanSource interface) in the ABBYY FineReader Engine API — This object exposes a set of properties and methods concerned with scanning source.
- [BeginScan Method of the ScanSource Object](https://docs.abbyy.com/fine-reader/engine/api-reference/mechanism-objects/scansource/beginscan-method.md): BeginScan method of the ScanSource Object in the ABBYY FineReader Engine API — This method starts an asynchronous scanning operation and returns immediately.
- [CancelScan Method of the ScanSource Object](https://docs.abbyy.com/fine-reader/engine/api-reference/mechanism-objects/scansource/cancelscan-method.md): CancelScan method of the ScanSource Object in the ABBYY FineReader Engine API — This method cancels the asynchronous scanning operation.
- [ResetSettings Method of the ScanSource Object](https://docs.abbyy.com/fine-reader/engine/api-reference/mechanism-objects/scansource/resetsettings-method.md): ResetSettings method of the ScanSource Object in the ABBYY FineReader Engine API — This method resets all settings of the ScanSource object to their default values.
- [Scan Method of the ScanSource Object](https://docs.abbyy.com/fine-reader/engine/api-reference/mechanism-objects/scansource/scan-method.md): Scan method of the ScanSource Object in the ABBYY FineReader Engine API — This method performs scanning of one or more images.
- [ScanSourceCapabilities Object (IScanSourceCapabilities Interface)](https://docs.abbyy.com/fine-reader/engine/api-reference/mechanism-objects/scansourcecapabilities.md): ScanSourceCapabilities object (IScanSourceCapabilities interface) in the ABBYY FineReader Engine API — This object provides access to possible settings of the scanning source.
- [Compressions Property of the ScanSourceCapabilities Object](https://docs.abbyy.com/fine-reader/engine/api-reference/mechanism-objects/scansourcecapabilities/compressions-property.md): Compressions property of the ScanSourceCapabilities Object in the ABBYY FineReader Engine API — The ScanSourceCapabilities object provides access to possible settings of scanning source, but available modes of...
- [ScanSources Object (IScanSources Interface)](https://docs.abbyy.com/fine-reader/engine/api-reference/mechanism-objects/scansources.md): ScanSources object (IScanSources interface) in the ABBYY FineReader Engine API — This object represents a collection of scanning sources.
- [Element Property](https://docs.abbyy.com/fine-reader/engine/api-reference/mechanism-objects/scansources/element-property.md): Element property of the ScanSources Object in the ABBYY FineReader Engine API — This property provides access to a single element of ABBYY FineReader Engine collection.
- [Item Method](https://docs.abbyy.com/fine-reader/engine/api-reference/mechanism-objects/scansources/item-method.md): Item method of the ScanSources Object in the ABBYY FineReader Engine API — This method provides access to a single element of a FineReader Engine collection.
- [ScanSourceSettings Object (IScanSourceSettings Interface)](https://docs.abbyy.com/fine-reader/engine/api-reference/mechanism-objects/scansourcesettings.md): ScanSourceSettings object (IScanSourceSettings interface) in the ABBYY FineReader Engine API — This object provides access to the scanning settings of a source.

## Document Comparison Objects

- [Document Comparison Objects](https://docs.abbyy.com/fine-reader/engine/api-reference/document-comparison-objects.md): Document Comparison Objects in the ABBYY FineReader Engine API — ABBYY FineReader Engine provides the Comparator object to compare the original document or the page with their copies and find the differences; you may...
- [Change Object (IChange Interface)](https://docs.abbyy.com/fine-reader/engine/api-reference/document-comparison-objects/change.md): Change object (IChange interface) in the ABBYY FineReader Engine API — This object represents one difference between the original and the copy.
- [GetAsPictureChange Method of the Change Object](https://docs.abbyy.com/fine-reader/engine/api-reference/document-comparison-objects/change/getaspicturechange-method.md): GetAsPictureChange method of the Change Object in the ABBYY FineReader Engine API — This method always returns NULL, as currently only text changes are supported.
- [GetAsTextChange Method of the Change Object](https://docs.abbyy.com/fine-reader/engine/api-reference/document-comparison-objects/change/getastextchange-method.md): GetAsTextChange method of the Change Object in the ABBYY FineReader Engine API — This method returns the detected change as the TextChange object.
- [ChangeLocation Object (IChangeLocation Interface)](https://docs.abbyy.com/fine-reader/engine/api-reference/document-comparison-objects/changelocation.md): ChangeLocation object (IChangeLocation interface) in the ABBYY FineReader Engine API — This object provides information about the location of the change.
- [RegionForPage Property of the ChangeLocation Object](https://docs.abbyy.com/fine-reader/engine/api-reference/document-comparison-objects/changelocation/regionforpage-property.md): RegionForPage property of the ChangeLocation Object in the ABBYY FineReader Engine API — Returns the region of the change on the specified page.
- [ChangePosition Object (IChangePosition Interface)](https://docs.abbyy.com/fine-reader/engine/api-reference/document-comparison-objects/changeposition.md): ChangePosition object (IChangePosition interface) in the ABBYY FineReader Engine API — This object represents the place in the document where a change begins or ends.
- [Changes Object (IChanges Interface)](https://docs.abbyy.com/fine-reader/engine/api-reference/document-comparison-objects/changes.md): Changes object (IChanges interface) in the ABBYY FineReader Engine API — This object is a collection of the Change objects.
- [Element Property](https://docs.abbyy.com/fine-reader/engine/api-reference/document-comparison-objects/changes/element-property.md): Element property of the Changes Object in the ABBYY FineReader Engine API — This property provides access to a single element of ABBYY FineReader Engine collection.
- [Item Method](https://docs.abbyy.com/fine-reader/engine/api-reference/document-comparison-objects/changes/item-method.md): Item method of the Changes Object in the ABBYY FineReader Engine API — This method provides access to a single element of a FineReader Engine collection.
- [Comparator Object (IComparator Interface)](https://docs.abbyy.com/fine-reader/engine/api-reference/document-comparison-objects/comparator.md): Comparator object (IComparator interface) in the ABBYY FineReader Engine API — This object provides the methods that compare the original document or page with their copies.
- [CompareDocuments Method of the Comparator Object](https://docs.abbyy.com/fine-reader/engine/api-reference/document-comparison-objects/comparator/comparedocuments-method.md): CompareDocuments method of the Comparator Object in the ABBYY FineReader Engine API — This method compares the original document with its copy.
- [ComparePages Method of the Comparator Object](https://docs.abbyy.com/fine-reader/engine/api-reference/document-comparison-objects/comparator/comparepages-method.md): ComparePages method of the Comparator Object in the ABBYY FineReader Engine API — This method compares a page from the original document with its copy.
- [ComparisonParams Object (IComparisonParams Interface)](https://docs.abbyy.com/fine-reader/engine/api-reference/document-comparison-objects/comparisonparams.md): ComparisonParams object (IComparisonParams interface) in the ABBYY FineReader Engine API — This object provides access to the comparison parameters.
- [ComparisonResult Object (IComparisonResult Interface)](https://docs.abbyy.com/fine-reader/engine/api-reference/document-comparison-objects/comparisonresult.md): ComparisonResult object (IComparisonResult interface) in the ABBYY FineReader Engine API — The result of comparing the original document or page with its copy.
- [Export Method of the ComparisonResult Object](https://docs.abbyy.com/fine-reader/engine/api-reference/document-comparison-objects/comparisonresult/export-method.md): Export method of the ComparisonResult Object in the ABBYY FineReader Engine API — This method exports the comparison result to a file of the specified format.
- [GetChangesForReferencePage Method of the ComparisonResult Object](https://docs.abbyy.com/fine-reader/engine/api-reference/document-comparison-objects/comparisonresult/getchangesforreferencepage-method.md): GetChangesForReferencePage method of the ComparisonResult Object in the ABBYY FineReader Engine API — This method returns all detected changes for the original page by index.
- [GetChangesForUserPage Method of the ComparisonResult Object](https://docs.abbyy.com/fine-reader/engine/api-reference/document-comparison-objects/comparisonresult/getchangesforuserpage-method.md): GetChangesForUserPage method of the ComparisonResult Object in the ABBYY FineReader Engine API — This method returns all detected changes for the page copy by index.
- [PictureChange Object (IPictureChange Interface)](https://docs.abbyy.com/fine-reader/engine/api-reference/document-comparison-objects/picturechange.md): PictureChange object (IPictureChange interface) in the ABBYY FineReader Engine API — Not implemented.
- [TextChange Object (ITextChange Interface)](https://docs.abbyy.com/fine-reader/engine/api-reference/document-comparison-objects/textchange.md): TextChange object (ITextChange interface) in the ABBYY FineReader Engine API — This object represents a change made in the document text.

## Batch Processor

- [BatchProcessor Object and Related Interfaces](https://docs.abbyy.com/fine-reader/engine/api-reference/batch-processor.md): BatchProcessor Object and Related Interfaces in the ABBYY FineReader Engine API — BatchProcessor object is a processor object which converts input images into the recognized pages (FRPage objects).
- [BatchProcessor Object (IBatchProcessor Interface)](https://docs.abbyy.com/fine-reader/engine/api-reference/batch-processor/batchprocessor.md): BatchProcessor object (IBatchProcessor interface) in the ABBYY FineReader Engine API — This is a processor object which converts input images into the recognized pages (FRPage objects).
- [GetNextProcessedPage Method of the BatchProcessor Object](https://docs.abbyy.com/fine-reader/engine/api-reference/batch-processor/batchprocessor/getnextprocessedpage-method.md): GetNextProcessedPage method of the BatchProcessor Object in the ABBYY FineReader Engine API — This method provides the background processing until the next recognized image is available.
- [ProcessPageAsync Method of the BatchProcessor Object](https://docs.abbyy.com/fine-reader/engine/api-reference/batch-processor/batchprocessor/processpageasync-method.md): ProcessPageAsync method of the BatchProcessor Object in the ABBYY FineReader Engine API — This method allows you to repeat processing of a page with another parameters.
- [Start Method of the BatchProcessor Object](https://docs.abbyy.com/fine-reader/engine/api-reference/batch-processor/batchprocessor/start-method.md): Start method of the BatchProcessor Object in the ABBYY FineReader Engine API — This method prepares the Batch Processor for work.
- [IAsyncProcessingCallback Interface](https://docs.abbyy.com/fine-reader/engine/api-reference/batch-processor/iasyncprocessingcallback.md): IAsyncProcessingCallback interface in the ABBYY FineReader Engine API — This is a callback interface that is used for managing the work of the BatchProcessor object and reporting errors, occurred during processing.
- [OnError Method of the IAsyncProcessingCallback Interface](https://docs.abbyy.com/fine-reader/engine/api-reference/batch-processor/iasyncprocessingcallback/onerror-method.md): OnError method of the IAsyncProcessingCallback Interface in the ABBYY FineReader Engine API — This method is implemented on the client-side.
- [OnProgress Method of the IAsyncProcessingCallback Interface](https://docs.abbyy.com/fine-reader/engine/api-reference/batch-processor/iasyncprocessingcallback/onprogress-method.md): OnProgress method of the IAsyncProcessingCallback Interface in the ABBYY FineReader Engine API — This method is implemented on the client-side.
- [IFileAdapter Interface](https://docs.abbyy.com/fine-reader/engine/api-reference/batch-processor/ifileadapter.md): IFileAdapter interface in the ABBYY FineReader Engine API — This is the interface for a file adapter.
- [GetFileName Method of the IFileAdapter Interface](https://docs.abbyy.com/fine-reader/engine/api-reference/batch-processor/ifileadapter/getfilename-method.md): GetFileName method of the IFileAdapter Interface in the ABBYY FineReader Engine API — This method is implemented on the client-side.
- [GetPagesToProcess Method of the IFileAdapter Interface](https://docs.abbyy.com/fine-reader/engine/api-reference/batch-processor/ifileadapter/getpagestoprocess-method.md): GetPagesToProcess method of the IFileAdapter Interface in the ABBYY FineReader Engine API — This method is implemented on the client-side.
- [GetPassword Method of the IFileAdapter Interface](https://docs.abbyy.com/fine-reader/engine/api-reference/batch-processor/ifileadapter/getpassword-method.md): GetPassword method of the IFileAdapter Interface in the ABBYY FineReader Engine API — This method is implemented on the client-side.
- [IImageSource Interface](https://docs.abbyy.com/fine-reader/engine/api-reference/batch-processor/iimagesource.md): IImageSource interface in the ABBYY FineReader Engine API — This is the interface for a custom source of images.
- [GetNextImageDocument Method of the IImageSource Interface](https://docs.abbyy.com/fine-reader/engine/api-reference/batch-processor/iimagesource/getnextimagedocument-method.md): GetNextImageDocument method of the IImageSource Interface in the ABBYY FineReader Engine API — This method is implemented on the client-side.
- [GetNextImageFile Method of the IImageSource Interface](https://docs.abbyy.com/fine-reader/engine/api-reference/batch-processor/iimagesource/getnextimagefile-method.md): GetNextImageFile method of the IImageSource Interface in the ABBYY FineReader Engine API — This method is implemented on the client-side.
- [IsEmpty Method of the IImageSource Interface](https://docs.abbyy.com/fine-reader/engine/api-reference/batch-processor/iimagesource/isempty-method.md): IsEmpty method of the IImageSource Interface in the ABBYY FineReader Engine API — This method is implemented on the client-side.

## License-Related Objects

- [License-Related Objects](https://docs.abbyy.com/fine-reader/engine/api-reference/license-related-objects.md): License-Related Objects in the ABBYY FineReader Engine API — This section contains descriptions of the following license-related objects:
- [ILicensingConnectionRecoveryCallback Interface](https://docs.abbyy.com/fine-reader/engine/api-reference/license-related-objects/ilicensingconnectionrecoverycallback.md): ILicensingConnectionRecoveryCallback interface in the ABBYY FineReader Engine API — This is a callback interface that can be used when the connection to the license server breaks.
- [OnDisconnect Method of the ILicensingConnectionRecoveryCallback Interface](https://docs.abbyy.com/fine-reader/engine/api-reference/license-related-objects/ilicensingconnectionrecoverycallback/ondisconnect-method.md): OnDisconnect method of the ILicensingConnectionRecoveryCallback Interface in the ABBYY FineReader Engine API — This method is implemented on the client-side.
- [License Object (ILicense Interface)](https://docs.abbyy.com/fine-reader/engine/api-reference/license-related-objects/license.md): License object (ILicense interface) in the ABBYY FineReader Engine API — This object stores information about the current license.
- [ExpirationDate Method of the License Object](https://docs.abbyy.com/fine-reader/engine/api-reference/license-related-objects/license/expirationdate-method.md): ExpirationDate method of the License Object in the ABBYY FineReader Engine API — This method returns the date at which the license will stop working if the license has an absolute or relative time limitation.
- [Volume Property of the License Object](https://docs.abbyy.com/fine-reader/engine/api-reference/license-related-objects/license/volume-property.md): Volume property of the License Object in the ABBYY FineReader Engine API — This property provides access to the total number of pages/characters which can be processed during a period if the license has such a...
- [VolumeRefreshingDate Method of the License Object](https://docs.abbyy.com/fine-reader/engine/api-reference/license-related-objects/license/volumerefreshingdate-method.md): VolumeRefreshingDate method of the License Object in the ABBYY FineReader Engine API — This property provides access to the date on which the license limits in a number of processed pages will be renewed.
- [VolumeRefreshingPeriod Property of the License Object](https://docs.abbyy.com/fine-reader/engine/api-reference/license-related-objects/license/volumerefreshingperiod-property.md): VolumeRefreshingPeriod property of the License Object in the ABBYY FineReader Engine API — This property provides access to the limitation period if the license limits the number of processed pages/characters during...
- [VolumeRemaining Property of the License Object](https://docs.abbyy.com/fine-reader/engine/api-reference/license-related-objects/license/volumeremaining-property.md): VolumeRemaining property of the License Object in the ABBYY FineReader Engine API — This property provides access to the remaining number of pages/characters which can be processed till the end of the current period if...
- [Licenses Object (ILicenses Interface)](https://docs.abbyy.com/fine-reader/engine/api-reference/license-related-objects/licenses.md): Licenses object (ILicenses interface) in the ABBYY FineReader Engine API — This object is a collection of available (activated) licenses.
- [Element Property](https://docs.abbyy.com/fine-reader/engine/api-reference/license-related-objects/licenses/element-property.md): Element property of the Licenses Object in the ABBYY FineReader Engine API — This property provides access to a single element of ABBYY FineReader Engine collection.
- [Find Method of the Licenses Object](https://docs.abbyy.com/fine-reader/engine/api-reference/license-related-objects/licenses/find-method.md): Find method of the Licenses Object in the ABBYY FineReader Engine API — This method provides access to the license by its serial number.
- [Item Method](https://docs.abbyy.com/fine-reader/engine/api-reference/license-related-objects/licenses/item-method.md): Item method of the Licenses Object in the ABBYY FineReader Engine API — This method provides access to a single element of a FineReader Engine collection.

## Engine Loaders

- [Engine Loaders Overview](https://docs.abbyy.com/fine-reader/engine/api-reference/engine-loaders.md): Engine Loaders Overview in the ABBYY FineReader Engine API — This section describes the interfaces and objects which can be used for loading and unloading the Engine object.
- [IEngineLoader Interface](https://docs.abbyy.com/fine-reader/engine/api-reference/engine-loaders/iengineloader.md): IEngineLoader interface in the ABBYY FineReader Engine API — This interface is used specifically to load and unload the Engine object.
- [ExplicitlyUnload Method of the IEngineLoader Interface](https://docs.abbyy.com/fine-reader/engine/api-reference/engine-loaders/iengineloader/explicitlyunload-method.md): ExplicitlyUnload method of the IEngineLoader Interface in the ABBYY FineReader Engine API — This method deinitializes ABBYY FineReader Engine.
- [InitializeEngine Method of the IEngineLoader Interface](https://docs.abbyy.com/fine-reader/engine/api-reference/engine-loaders/iengineloader/initializeengine-method.md): InitializeEngine method of the IEngineLoader Interface in the ABBYY FineReader Engine API — This method is used to get a pointer to the IEngine interface.
- [IHostProcessControl Interface](https://docs.abbyy.com/fine-reader/engine/api-reference/engine-loaders/ihostprocesscontrol.md): IHostProcessControl interface in the ABBYY FineReader Engine API — This interface can be used to manage the process which hosts FineReader Engine.
- [SetClientProcessId Method of the IHostProcessControl Interface](https://docs.abbyy.com/fine-reader/engine/api-reference/engine-loaders/ihostprocesscontrol/setclientprocessid-method.md): SetClientProcessId method of the IHostProcessControl Interface in the ABBYY FineReader Engine API — Sets the ID of the client process which uses FineReader Engine.
- [SetPriorityClass Method of the IHostProcessControl Interface](https://docs.abbyy.com/fine-reader/engine/api-reference/engine-loaders/ihostprocesscontrol/setpriorityclass-method.md): SetPriorityClass method of the IHostProcessControl Interface in the ABBYY FineReader Engine API — Sets the priority class of the host process.
- [InprocLoader Object](https://docs.abbyy.com/fine-reader/engine/api-reference/engine-loaders/inprocloader.md): InprocLoader Object in the ABBYY FineReader Engine API — This object implements the IEngineLoader interface, which provides methods for loading and unloading the Engine object.
- [OutprocLoader Object](https://docs.abbyy.com/fine-reader/engine/api-reference/engine-loaders/outprocloader.md): OutprocLoader Object in the ABBYY FineReader Engine API — This object implements the IEngineLoader which provides methods for loading and unloading the Engine object.

## Functions

- [Functions](https://docs.abbyy.com/fine-reader/engine/api-reference/functions.md): Functions enumeration in the ABBYY FineReader Engine API — This section describes ABBYY FineReader Engine functions.
- [DeinitializeEngine Function](https://docs.abbyy.com/fine-reader/engine/api-reference/functions/deinitializeengine-function.md): DeinitializeEngine function in the ABBYY FineReader Engine API — This function deinitializes ABBYY FineReader Engine.
- [InitializeEngine Function](https://docs.abbyy.com/fine-reader/engine/api-reference/functions/initializeengine-function.md): InitializeEngine function in the ABBYY FineReader Engine API — This function is used to get a pointer to the IEngine interface.