Indicate edge direction

[danielabar]

Now that edges are svg path elements, add an arrowhead or some sort of indicator at the target end, to make the direction obvious.

[matanox]

An edge that has width beyond the noticeable line itself, may alternatively point at the direction it is meant to show, by just narrowing down towards that side of itself. This is sort of the trick of dropping a component (the arrow-head) for simplicity.

Chord diagrams sometimes present such edges (which in the case of chord diagrams of that kind, only represent a ratio, not directionality, but they give an idea of how edges of varying width look like).

[matanox]

Intuitively in the domain of code visualization, inheritance might be more distinguishable from e.g. a call relationship, if it looks more like a fat chord than just a different color of arrow. The "widening towards" metaphor, sort of.