Dilate/erode image. Applies a morphological dilate (radius > 0) or erode (radius < 0) to the mask data.
Dilate/erode radius in pixels where radiusR is applied as is, regardless of whether the mask is downsampled (int -100..100).
Primarily used to slightly grow or shrink a mask to avoid artifacts around the edge of the mask.
Applies to the current layer or to layer
op_growMaskR=0, for no change.