> ## Documentation Index
> Fetch the complete documentation index at: https://docs.abbyy.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Processing Methods of the Engine Object

The [Engine](/fine-reader/engine/api-reference/engine-object-iengine-interface) object exposes a set of processing methods. They are used to open and convert image files or bitmaps (win), or process an image/PDF file directly. However, using the methods of the [FRDocument](/fine-reader/engine/api-reference/document-related-objects/frdocument) object is more convenient in most scenarios.

| Name                                                                                                                                                                                           | Description                                                                                                                                                                                                                                                                                                               |
| ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| [GetNumberOfPagesInImageFile](/fine-reader/engine/api-reference/engine-object-iengine-interface/processing-methods/getnumberofpagesinimagefile-method)                                         | Returns the number of pages in an image file.                                                                                                                                                                                                                                                                             |
| [InjectTextLayer](/fine-reader/engine/api-reference/engine-object-iengine-interface/processing-methods/injecttextlayer-method)                                                                 | Processes the input PDF file and creates a searchable PDF file of the "image on text" type which contains the same page images and the text layer created from the recognized text.                                                                                                                                       |
| [IsPdfPortfolio](/fine-reader/engine/api-reference/engine-object-iengine-interface/processing-methods/ispdfportfolio-method)                                                                   | Determines if a PDF file is a PDF Portfolio.                                                                                                                                                                                                                                                                              |
| [IsPdfPortfolioFromStream](/fine-reader/engine/api-reference/engine-object-iengine-interface/processing-methods/ispdfportfoliofromstream-method)                                               | Determines if a PDF file added from the stream is a PDF Portfolio.                                                                                                                                                                                                                                                        |
| [IsPdfWithTextualContent](/fine-reader/engine/api-reference/engine-object-iengine-interface/processing-methods/ispdfwithtextualcontent-method)                                                 | Determines if any of the pages of a PDF file contains text layer.                                                                                                                                                                                                                                                         |
| [IsPdfWithTextualContentFromStream](/fine-reader/engine/api-reference/engine-object-iengine-interface/processing-methods/ispdfwithtextualcontentfromstream-method)                             | Determines if any of the pages of a PDF file added from the stream contains text layer.                                                                                                                                                                                                                                   |
| [LoadImageDoc](/fine-reader/engine/api-reference/engine-object-iengine-interface/processing-methods/loadimagedoc-method)                                                                       | Restores the contents of the [ImageDocument](/fine-reader/engine/api-reference/image-related-objects/imagedocument) object from the folder on disk.                                                                                                                                                                       |
| [LoadImageDocFromFile](/fine-reader/engine/api-reference/engine-object-iengine-interface/processing-methods/loadimagedocfromfile-method)                                                       | Restores the contents of the [ImageDocument](/fine-reader/engine/api-reference/image-related-objects/imagedocument) object from the file previously saved with the help of the [IImageDocument::SaveToFile](/fine-reader/engine/api-reference/image-related-objects/imagedocument/savetofile-method) method.              |
| [LoadImageDocFromMemory](/fine-reader/engine/api-reference/engine-object-iengine-interface/processing-methods/loadimagedocfrommemory-method) <br /><br /> **Note:** *Implemented for Windows.* | Restores the contents of the [ImageDocument](/fine-reader/engine/api-reference/image-related-objects/imagedocument) object from the global memory, where it was previously saved by the [IImageDocument::SaveToMemory](/fine-reader/engine/api-reference/image-related-objects/imagedocument/savetomemory-method) method. |
| [OpenBitmap](/fine-reader/engine/api-reference/engine-object-iengine-interface/processing-methods/openbitmap-method)                                                                           | Opens the specified bitmap image (HBITMAP). <br /><br /> **Note:** *Not implemented for Linux and macOS.*                                                                                                                                                                                                                 |
| [OpenBitmapBits](/fine-reader/engine/api-reference/engine-object-iengine-interface/processing-methods/openbitmapbits-method)                                                                   | Opens the specified [bitmap data](/fine-reader/engine/api-reference/enumerations/bitmapbitsformatenum). <br /><br /> **Note:** *Not implemented for Linux and macOS.*                                                                                                                                                     |
| [OpenDib](/fine-reader/engine/api-reference/engine-object-iengine-interface/processing-methods/opendib-method)                                                                                 | Opens the specified device-independent bitmap. <br /><br /> **Note:** *Not implemented for Linux and macOS.*                                                                                                                                                                                                              |
| [OpenImageFileFromMemory](/fine-reader/engine/api-reference/engine-object-iengine-interface/processing-methods/openimagefilefrommemory-method)                                                 | Opens an image file from the global memory, where it was previously loaded by the user.                                                                                                                                                                                                                                   |
| [PrepareBitmap](/fine-reader/engine/api-reference/engine-object-iengine-interface/processing-methods/preparebitmap-method)                                                                     | Creates a copy of the specified bitmap image (HBITMAP) in FineReader Engine [internal image format](/fine-reader/engine/guided-tour/advanced-techniques/working-with-images#internal_format). <br /><br /> **Note:** *Not implemented for Linux and macOS.*                                                               |
| [PrepareBitmapBits](/fine-reader/engine/api-reference/engine-object-iengine-interface/processing-methods/preparebitmapbits-method)                                                             | Creates a copy of the specified [bitmap data](/fine-reader/engine/api-reference/enumerations/bitmapbitsformatenum) in FineReader Engine [internal image format](/fine-reader/engine/guided-tour/advanced-techniques/working-with-images#internal_format). <br /><br /> **Note:** *Not implemented for Linux and macOS.*   |
| [PrepareDib](/fine-reader/engine/api-reference/engine-object-iengine-interface/processing-methods/preparedib-method)                                                                           | Creates a copy of the specified device-independent bitmap in FineReader Engine [internal image format](/fine-reader/engine/guided-tour/advanced-techniques/working-with-images#internal_format). <br /><br /> **Note:** *Not implemented for Linux and macOS.*                                                            |
| [RecognizeImageFile](/fine-reader/engine/api-reference/engine-object-iengine-interface/processing-methods/recognizeimagefile-method)                                                           | Opens the specified image file, performs its preprocessing, layout analysis, recognition, page and document synthesis, and exports the recognized text into the selected output format.                                                                                                                                   |

## See also

[Engine](/fine-reader/engine/api-reference/engine-object-iengine-interface)