The following operations are available.
Keep layer contents
If this option is active, the content of the draw layer will not be
erased after a fixation.
Invert
This inverts the selection of the draw layer.
Smooth
Smooths the content of the draw layer by a settable value. Used
correctly it can e.g. create shadow effects.
Transparency
Affects the intensities of the draw layer. Values smaller zero
increase the portion of the base image, values greater zero the portion
of the effect layer on the result.
Antialiasing
Rounds "edgy" parts of the draw layer with additional tranparency
value.
Copy to picture
Creates a new image containing the contents of the draw layer as
base image.
Copy from picture
Uses the contents of another image as draw layer. The selected
image has to have the same size, though.