mask

Copy and flip between a main layer and a mask layer in the selected glyphs.

RF3 RoboFont 3 code which still works in RoboFont 4. Not updated to the new RoboFont 4 APIs yet.

main layer
select the main layer
mask layer
select another layer as the mask layer
copy
copy contents of the main layer to the mask layer
flip
flip contents between main and mask layers
clear
clear contents of the mask layer
copy width

copy glyph widths when copying between layers
this option is no longer necessary in RoboFont 4