[FEA] Radial and linear hierarchical layouts

[lmeyerov]

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From discussions with @sevickson :

The radial and linear layout modes are helpful for API usage, so we should make it easy for pygraphistry/api users to make them!

This comes down to a few things, and can be done in stages:

Components

PyGraphistry layout: mapping a graph -> linear/radial coordinates + axis object

Input:

• g: nodes/edges df with src/dst/node bindings
• `orientation :: linear | radial
• ?sort_key :: str
• axis :: [ { label : str, ?key_val: any, ?sort: [ { ?key: str, ascending: bool } ], color : str | int, ?thickness: int, ?width : int, stroke : solid | dotted | ..., ?spacing : int } ]

Output:

• g.nodes set with x/y
• axis objects list

PyGraphistry hooks for specifying the layout

• Graph: g.layout(g.layout_radial(...)), where g.layout_radialinternally is justg * ... -> g
• Hypergraph: ???
• .plot(): Uses complexEncodings API to pass along the axis?

Rollout

• Phase 1: Run the layout locally via PyGraphistry <-- community-contributable for the layout alg part, and we should carry the water for plugging into pygraphistry and the complex encodings api

• Phase 2: Support for all API users and on bigger scale via mirroring on the backend

• Phase 3: ... with post-load in-UI editing