New experimental asset graph layout algorithms

[salazarm]

We are experimenting with new and exponentially faster layout algorithms to dramatically improve the loading of asset graphs with 1,000+ assets. Two new feature flags have been added under user settings:

Below are the technical definitions. Network-simplex is the current algorithm which is iterative and is too slow for very large (1,000+ assets) graphs. We are considering changing to one of the other two options (tight-tree or longest-path) and would love your input into which you would prefer and why.

The above definition is very technical but at a high level one of the main differences is that longest-path will align all of the leaf nodes at the bottom where as tight-tree aligns all of the root nodes at the top. Another difference is that when expanding/collapsing subgraphs, longest-path results in graphs that are not drastically different from their unexpanded/uncollapsed counterparts.

Please experiment with the options and let us know what you think!

(Note that you should only enable one of the flags at a time, otherwise tight-tree will take precedence over longest-path)

[maxwelljoslyn]

Here's a subset of my asset graph (with redacted asset and group names).

I'm using longest-path in this screenshot, and frankly it looks pretty bad. It's hard to read the arrows when they overlap like this.

I also tried tight-tree. That layout ended up almost the same as simplex, except that it moved some groups to different positions. But I didn't have any readability problems. So in the absence of any other information, tight-tree would definitely be my preference.

[maxwelljoslyn]

To put it another way, I think that the priority for graph drawing algorithms should be ensuring that arrows don't overlap. I don't really have a preference how that happens internally.

[maxwelljoslyn]

Since I'm on the subject of layout algorithms: I would find it useful to have layout use both horizontal and vertical space. One way to measure that would be a constraint that tries to minimize the area of an imaginary square with its upper left corner at the uppermost, leftmost asset, and its bottom right corner at the bottom-most, rightmost asset. That would help me see more stuff on screen without scrolling.