# Erode node¶

This documentation is for version 2.1 of Erode (net.sf.cimg.CImgErode).

## Description¶

Erode (or dilate) input stream by a rectangular structuring element of specified size and Neumann boundary conditions (pixels out of the image get the value of the nearest pixel).

A negative size will perform a dilation instead of an erosion.

Different sizes can be given for the x and y axis.

Uses the ‘erode’ and ‘dilate’ functions from the CImg library.

CImg is a free, open-source library distributed under the CeCILL-C (close to the GNU LGPL) or CeCILL (compatible with the GNU GPL) licenses. It can be used in commercial applications (see http://cimg.eu).

## Inputs¶

Input Description Optional
Source   No
Size / size Integer x: 1 y: 1 Width/height of the rectangular structuring element is 2*size+1, in pixel units (>=0).
Expand RoD / expandRoD Boolean On Expand the source region of definition by 2*size pixels if size is negative
(Un)premult / premult Boolean Off Divide the image by the alpha channel before processing, and re-multiply it afterwards. Use if the input images are premultiplied.
Invert Mask / maskInvert Boolean Off When checked, the effect is fully applied where the mask is 0.
Mix / mix Double 1 Mix factor between the original and the transformed image.