FRPage Object (IFRPage Interface)

FRPage object (IFRPage interface) in the ABBYY FineReader Engine API — Represents a single page, either from an FRDocument or from a Batch Processor (Linux/Windows); exposes page-level analyze, recognize, synthesize, export, and preprocessing methods plus cache-dictionary operations.

This object corresponds to a page.

In Linux and Windows, this can be either a page of a document, or a page produced by Batch Processor.

It provides a set of methods for page preprocessing, analysis, recognition, page synthesis, and export. The methods of this object do not perform document synthesis (except for the Synthesize method). Before exporting the results you must explicitly call some method which performs document synthesis. See Tuning Parameters of Preprocessing, Analysis, Recognition, and Synthesis for details.

The FRPage object is a so-called “connectable object.” For Visual Basic in FRE for Windows, it may be declared WithEvents. For C++ (all supported operating systems), this means that it supports the IConnectionPointContainer interface. To receive notification events during processing, C++ users should create an object derived from the IFRPageEvents interface and…

• In Linux and macOS, advise it to the FRPage object by the call to the AdviseFREngineObject global function.
• In Windows: set up the connection between it and the events source implemented in the FRPage object by standard COM means.

In Windows: The methods of the FRPage object report information about page processing progress through special outgoing interfaces. These interfaces are IFRPageEvents (for C++) and the dispinterface DIFRPageEvents (for Visual Basic). It should be noted that Visual Basic users should not care for details of implementing event interfaces, as this development platform provides easy means for handling them.

Properties

Name	Type	Description
Application	Engine, read-only	Returns the Engine object.
Common attributes
Document	FRDocument, read-only	Returns the document which contains the page.
ImageDocument	ImageDocument, read-only	Provides access to the image of the page.
Layout	Layout	Provides access to the layout of the page. When you assign a Layout object to this property (for example, when transferring data from one page to another), the logical structure of the corresponding document becomes invalid. It is necessary to restore the document structure by calling one of the synthesis methods. However, you do not need to perform synthesis for the whole document, it is only necessary to synthesize changed pages, e.g., using the Synthesize method.
PlainText	PlainText, read-only	Returns the text of the page in a special “plain text” format.
SourceImagePath	BSTR, read-only	Specifies the full path to the source image of the page.
Page languages
BasicLanguage	BSTR, read-only	Specifies the main language of the recognized page. The property contains the internal name of the first language in the collection of detected languages (DetectedLanguages property). This property has a meaningful value only if recognition was performed with the automatic language detection on (see the IRecognizerParams::LanguageDetectionMode property for details). By default, it is an empty string.
DetectedLanguages	DetectedLanguages, read-only	Provides access to the collection of recognition languages detected on the recognized page. Languages in the collection are sorted by the frequency of occurrence: from the most frequently occurred to the least. This property has a meaningful value only if recognition was performed with the automatic language detection on (see the IRecognizerParams::LanguageDetectionMode property for details). The list of languages is updated only after recognition, i.e., if you edit the layout of the page manually, the collection remains the same.
Page structure
PageStructureOutOfDate	VARIANT_BOOL, read-only	Specifies whether the logical structure of the page is out of date. If this property is TRUE, you should perform document synthesis for the page before export. Otherwise, an error will occur during export. This property is useful when you work with Visual Components. The logical structure of a page becomes invalid if a user changes layout of this page via GUI of Visual Components. If export of such page is performed using commands available in Visual Components, Visual Components synthesize the page automatically. But if you use FineReader Engine API methods for export, you are responsible for performing document synthesis for the page before export.
SourceFilePageIndex	int, read-only	Returns the index of the page in the source file.
SourceHasDigitalSignature	VARIANT_BOOL, read-only	Indicates whether the source file of this page was a digitally signed PDF.
Business cards
BusinessCards	BusinessCards, read-only	Provides access to the collection of business cards detected on the page.
Undo support
UndoSupport	VARIANT_BOOL	Visual Components are currently only supported for Windows. Specifies whether the Undo and Redo methods are allowed. If the value of this property is TRUE, all the commands called either with the help of the methods that can modify the page (such as methods of the FRPage or the ImageDocument object) or from the Windows Visual Components can be added to an undo stack. In this case, the commands that were called from the Visual Components are added to the stack automatically. To add to the stack the commands which were called from the API, use the Update method. The property cannot be set to FALSE for a page which has been opened in Visual Components.
CanRedo	VARIANT_BOOL, read-only	Visual Components are currently only supported for Windows. Specifies whether the Redo method can be executed for the latest undone command which was called either with the help of one of the methods that can modify the page (such as methods of the FRPage or the ImageDocument object) or from one of the Visual Components.
CanUndo	VARIANT_BOOL, read-only	Visual Components are currently only supported for Windows. Specifies whether the Undo method can be executed for the latest command which was called either with the help of one of the methods that can modify the page (such as methods of the FRPage or the ImageDocument object) or from one of the Visual Components.

Methods

Name	Description
AddWordsToCacheDictionary	This method adds a group of words to the cache dictionary.
AddWordToCacheDictionary	This method adds one word to the cache dictionary.
Analyze	Analyzes the page.
AnalyzeRegion	Analyzes layout of the image inside the specified region.
AnalyzeTable	Replaces a specified block with a table block and analyzes the structure of the table.
CleanCacheDictionary	This method deletes all words from the cache dictionary.
DetectOrientation	Detects page orientation.
DetectResolution	Selects the best resolution from the specified range.
Export	Saves a page into a file in an external format.
ExtractBarcodes	Finds and recognizes all barcode blocks.
ExtractMrz	Extracts data from a machine-readable zone (MRZ).
FindPageSplitPosition	Finds the position where the image can be split.
Flush	Unloads and, if necessary, saves to disk the ImageDocument and the Layout objects corresponding to the FRPage object if there are no references to them. Saving to disk is an option, you can omit this stage if the data has not been changed.
IsEmpty	Checks if the page is empty.
LearnCheckmarks	Trains FineReader Engine to recognize checkmarks of a custom type.
PreprocessAnalyzeRecognize	Performs preprocessing, layout analysis, recognition, and page synthesis of the page.
Preprocess	Preprocesses the page: corrects page orientation, inversion, geometrical distortions. Page preprocessing is performed before page analysis.
Recognize	Recognizes the page and performs page synthesis.
RecognizeBlocks	Recognizes text and performs page synthesis in an explicitly specified set of blocks.
Redo	Note: Visual Components are currently only supported for Windows. Redoes the latest undone command which was called from the FineReader Engine API.
Synthesize	Performs document synthesis for the individual page. In Linux and Windows, this method may be useful when processing one-page documents with Batch Processor.
SynthesizeBusinessCard	Tries to find business card fields in the specified recognized region.
SynthesizeBusinessCardEx	Tries to find business card fields in the specified recognized region using the synthesis parameters.
Undo	Note: Visual Components are currently only supported for Windows. Undoes the latest command which was called from the FineReader Engine API.
Update	Note: Visual Components are currently only supported for Windows. Transfers changes in the page layout made via FineReader Engine API to Visual Components and saves these changes to the undo stack. Note: When you call this method, the logical structure of the corresponding document becomes invalid. It is necessary to restore the document structure by calling one of the synthesis methods. However, you do not need to perform synthesis for the whole document, it is only necessary to synthesize changed pages, e.g., using the Synthesize method.

Related objects

Object Diagram

Output parameter

This object is the output parameter of the following methods:

• Item method of the FRPages object
• In Linux and Windows: GetNextProcessedPage method of the BatchProcessor object

Input parameter

This object is passed as an input parameter to the following methods:

• IndexOf method of the FRPages object
• AddPage method of the FRDocument object
• AddPage method of the ExportFileWriter object
• CreateObjectFromPage method of the ClassificationEngine object
• OnProgress, OnWarning, OnRegionProcessed, OnPageProcessed methods of the IFRPageEvents interface
• PageRemoved method of the IFRPagesEvents interface
• ComparePages method of the Comparator object
• In Linux and Windows: ProcessPageAsync method of the BatchProcessor object
• In Windows, using Visual Components:
  • OnActivePageChanged, OnActivePageChanging methods of the DocumentViewerEvents interface
  • OnActivePageChanged, OnActivePageChanging method of the IImageViewerEvents interface
  • OnActivePageChanged method of the IZoomViewerEvents interface
  • OnActivePageChanged, OnActivePageChanging method of the ITextEditorEvents interface
  • OnActivePageChanged method of the ITextValidatorEvents interface

Related Visual Components

Samples

C# code

FREngine.IEngine engine;
string fileName;
FREngine.IBatchProcessor batchProcessor;
// We presume that Batch Processor is created and started
// Obtain recognized pages and export them to PDF format
FREngine.IFRPage page = batchProcessor.GetNextProcessedPage();
while( page != null ) {
 // Synthesize page before export
 page.Synthesize(null);
 // Export page to a file
 page.Export(fileName, FREngine.FileExportFormatEnum.FEF_PDF, null);
 page = batchProcessor.GetNextProcessedPage();
}

The object is used in the following code samples:

• macOS: Business Card Recognition and RecognizedTextProcessing
• Linux: BCR, BatchProcessing, CustomLanguage, CommandLineInterface
• Windows: BatchProcessing, CustomLanguage, CommandLineInterface, RecognizedTextProcessing, VisualComponents and demo tools: BatchProcessingRecognition, Engine Predefined Processing Profiles.

See also

FRPages

Working with Connectable Objects

Working with Properties