Visualization of contrary and contradictory relations

[ggbetz]

In a map, the following cases are visualized in the same way.

(A)

a
  <- b
  -> b

(B)

a
  >< b

That's unfortunate, because (A) espresses that a and b are contrary, not more, and (B) expresses that they are contradictory.

Suggestion: Red arrow with arrows at both ends for contradictory.

[ggbetz]

For example, in dot, this could be the visualization of a contradicory relation:

  n1 -> n0 [color="red", type="map-edge", dir="both", arrowhead="diamond", arrowtail="diamond"];

And this could be the visualization of a contrary relation:

  n1 -> n0 [color="red", type="map-edge", dir="both"];

[christianvoigt]

Currently dagre-d3 does not support arrow heads at both ends, but there is a pull request ready to be merged:

dagrejs/dagre-d3#316

Let's hope it gets merged soon. Until then, contrary and contradictory relations will only be one-headed in the Dagre-D3 map.

[christianvoigt]

This has still not been merged into Dagre and has changed to dagrejs/dagre-d3/pull/361