double getTopOffset(Vertex2d v, int offset) {
			return goingDown ? v.getTop() - offset : v.getBottom() + offset;
		}
Encapsulates knowledge of edge direction (up/down, left/right) and uses that knowledge
to report vertex offsets from the appropriate side and top/bottom
Ghidra/Features/FunctionGraphDecompilerExtension/src/main/java/ghidra/app/plugin/core/functiongraph/graph/layout/DecompilerNestedLayout.java