Pattern diagrams not displaying properly

[jtucker2]

Many of the pattern diagrams in the output are being displayed with no links and all of the nodes stacked on top of each other. Affected diagrams are all of the matching patterns and some of the construction and threat patterns. Root patterns aren't affected. It's not clear why some are affected and some aren't.

[scp93ch]

There is a complication in the diagram code which might help explain this issue.

We had an objective that all diagrams incorporating the same root pattern presented the root pattern nodes in the same arrangement so that they would all look similar and make visual comparisons easier. By default, the graphvis layout system would lay each diagram out independently and the root patterns would not appear the same.

To fix this, the root patterns are generated and then the coordinates of the root pattern nodes are read in somehow, and then when other diagrams are generated, the root pattern node coordinates are constrained to match. This worked (or at least I thought it did), but results in some diagrams having their nodes quite spread out and therefore hard to read.