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# OnToolEraseRect Method of the IImageViewerEvents Interface

> OnToolEraseRect method of the IImageViewerEvents Interface in ABBYY FineReader Engine Visual Components on Windows — This method is implemented on the client-side.

This method is implemented on the client-side. It is called by ABBYY FineReader Engine before erasing a part of an image, if this process has been invoked with the help of the [MI\_ChooseTool\_Eraser](/fine-reader/engine/visual-components-reference/imageviewer/image-viewer-commands#mi_choosetool_eraser) command of [Image Viewer](/fine-reader/engine/visual-components-reference/imageviewer). For the ways how this command can be called see the [Image Viewer Commands](/fine-reader/engine/visual-components-reference/imageviewer/image-viewer-commands) list.

The method delivers to the client information on the page which is going to be edited, and the coordinates of the erasing rectangle. With the help of this method it is possible to cancel the operation.

<Accordion title="See the illustration">
  <img src="https://mintcdn.com/abbyy/lsETHFYUFiongXSm/images/fine-reader/engine/editimage_erase.png?fit=max&auto=format&n=lsETHFYUFiongXSm&q=85&s=71c6db1793aae3aeb95713d990937d6c" alt="EditImage_Erase" width="568" height="426" data-path="images/fine-reader/engine/editimage_erase.png" />
</Accordion>

## Syntax

### C++

```cpp theme={null}
HRESULT OnToolEraseRect(
  IFRRectangle* Rect,
  int           PageIndex,
  VARIANT_BOOL* Cancel
);
```

### C\#

```csharp theme={null}
void OnToolEraseRect(
  IFRRectangle Rect,
  int         PageIndex,
  out bool    Cancel
);
```

### Visual Basic .NET

```vb theme={null}
Sub OnToolEraseRect( _
  Rect As IFRRectangle, _
  PageIndex As Integer, _
  ByRef Cancel As Boolean _
)
```

## Parameters

Rect

\[in] Contains the coordinates of the erasing rectangle as the [FRRectangle](/fine-reader/engine/api-reference/supplementary-objects-and-methods/frrectangle) object. The coordinates are specified in pixels relative to the document image.

PageIndex

\[in] Specifies the index of the page in the document.

Cancel

\[out] You may set this variable to TRUE to indicate that the process should be terminated. In this case, the image area inside the erasing rectangle will not be deleted.

## Return values

\[C++ only] If this method returns a value other than S\_OK, it indicates that an error occurred on the client-side, and in this case the value of the Cancel parameter is not taken into account.

## Remarks

The client implementation of this method must assure that all exceptions thrown inside the method are caught and handled and no exceptions are propagated outside the method. Propagation of an exception outside the method may lead to unpredictable results (such as program termination).

## See also

[IImageViewerEvents](/fine-reader/engine/visual-components-reference/iimageviewerevents)