> ## 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.

# IProcessingEvents Interface

This is a callback interface that is used by the [InjectTextLayer](/fine-reader/engine/api-reference/engine-object-iengine-interface/processing-methods/injecttextlayer-method) method of the [Engine](/fine-reader/engine/api-reference/engine-object-iengine-interface) object to report events during processing. This interface is implemented on the client-side.

An object receiving notifications through this interface's methods may do the following inside the methods' implementation:

* Process any system messages to help prevent the application from appearing unresponsive during long operations. This can be helpful in applications with a user interface.

* Report percentage of document analysis, recognition, and export.

* Report recognizer tips and warnings to the user.

* Report information about completion of the operation.

## Methods

| Name                                                                                                                            | Description                                                                             |
| ------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------- |
| [OnPageProcessed](/fine-reader/engine/api-reference/supplementary-objects-and-methods/iprocessingevents/onpageprocessed-method) | Delivers to the client information about page processing completed.                     |
| [OnProgress](/fine-reader/engine/api-reference/supplementary-objects-and-methods/iprocessingevents/onprogress-method)           | Delivers to the client information about approximate percentage of operation completed. |
| [OnWarning](/fine-reader/engine/api-reference/supplementary-objects-and-methods/iprocessingevents/onwarning-method)             | Delivers to the client tips and warnings which occurred during processing.              |

## Input parameter

The [InjectTextLayer](/fine-reader/engine/api-reference/engine-object-iengine-interface/processing-methods/injecttextlayer-method) method of the [Engine](/fine-reader/engine/api-reference/engine-object-iengine-interface) object receives a pointer to this interface as an input parameter.

## Remarks

In Linux, this interface does not work if the Engine object is loaded as an out-of-process server.