Chooses which side of an element or port a link attaches to when using the
mid-side anchor. 'auto' picks the side nearest the other end; 'horizontal'
and 'vertical' lock to left/right or top/bottom; the 'prefer-*' variants
favor one axis but fall back to the other; and the directional pairs
('top-bottom', 'left-right', etc.) pin the source and target to opposite
sides.
Chooses which side of an element or port a link attaches to when using the mid-side anchor.
'auto'picks the side nearest the other end;'horizontal'and'vertical'lock to left/right or top/bottom; the'prefer-*'variants favor one axis but fall back to the other; and the directional pairs ('top-bottom','left-right', etc.) pin the source and target to opposite sides.