Ability to group nodes visually and programmatically

[Stygmates]

Hi,
I started working on my own implementation of a graph using egui as well and came across your project and may use it instead.
I'm looking for a way to group nodes, both visually and programmatically and didn't find any reference to a similar feature in the code or in any discussion.
Is there anything similar I can use or is there any plan to implement such feature?

[setzer22]

I'm not entirely sure what you mean by grouping nodes. Is it something like a sub-graph, where a node in the parent graph is made out of nodes in some inner child graph? In that case, that is something I'm planning to do eventually in my main project, but there is nothing in this library to support it yet.

That being said, the philosophy behind this library is doing one thing well, and that is drawing a single interactive graph and let you manipulate nodes and connections. A "grouping" action can be implemented on top of this library with minimal modifications. You'd need to detect the action somehow (this may require a small addition, to allow selecting multiple nodes), and then replace the selected group of nodes with a single one. Inside the NodeData for the new node you could store a reference (more like a handle, to avoid lifetime issues) to another graph, and then all the semantics of grouping can be implemented on top of that.

Opening the sub-graph editor window would be as easy as drawing the child graph UI using the same library, and for that you have all the power of egui: You can draw them on different floating windows, replace one with another, make the sub-graph pop up over the parent, or whatever interface you come up with.

These are decisions that are too closely tied to the semantics of each application, so it's hard to come up with a generic implementation that suits all user's use cases. But if you have ideas about this please let me know! 😄