TikZ-SWIGs

The tikz-swigs package provides horizontally and vertically split elliptical (pairs of) nodes in TikZ.

The two new multi-part shapes are swig hsplit and swig vsplit. These build on and extend the existing ellipse split shape provided in the shapes.multipart TikZ library in the following ways:

• Space can be introduced physically separating the two sub-parts.
• The cut that divides the ellipse can be horizontal hsplit or vertical vsplit.
• The enclosing lines for each sub-part can be colored differently or can be double lines.
• With vsplit the position of the dividing line relative to the original undivided ellipse is determined based on the relative size of the label text for the two pieces.
• Anchors determined by angles are supported, for example mynode.170.

The package name derives from the fact that split ellipses of this type are used to represent Single-World Intervention Graph (SWIG) models which are used in counterfactual causal inference.

The tikz-swigs package is licensed under the The LaTeX Project Public License 1.3c and the GNU General Public License, version 2.

Thanks to Robin J. Evans, F. Richard Guo and Ilya Shpitser for providing guidance, motivation and encouragement.

– Thomas Richardson <thomasr@uw.edu> 9 July 2021