bel="anchor" href="#arg-erode-dilate-opening-closing-filter"></a></dt>
<dd><p><strong>Morphological operations (brush size)</strong></p><ul><li><p><code>dilate</code> puts the mask over every background pixel, and sets it to
foreground if any of the pixels covered by the mask is from the foreground.</p></li>
<li><p><code>erode</code> puts the mask over every foreground pixel, and sets it to
background if any of the pixels covered by the mask is from the background.</p></li>
<li><p><code>opening</code> perfo