Idea: Nodes

[vlappa]

Nodes / routing blocks is a very useful paradigm in many software applications: routing audio, video, editing parameters in graphical tools etc.

It's also a workflow which has good 'transfer' value between applications. If you have worked with it, you're easy to adapt to new software with the same sort of functionality:
https://youtu.be/I4mdMMu-3fc?feature=shared&t=3820

Nuklear has nodes functionality (See screenshot above and the gif in their readme):

https://github.com/Immediate-Mode-UI/Nuklear

[david-vanderson]

We have the beginnings of this in the "scroll canvas" demo, which shows putting boxed widgets in a pannable/zoomable infinite canvas.

I believe a few people are using dvui to develop more functional node editors, so hopefully we can learn what additional features dvui needs to be able to support this more easily.

[phatchman]

Sounds like an interesting little project. If I ever finish the grid I might take a look at this.

I think we need a few things over what dvui already has for this:

1. Connection points
2. Routable lines.
   • Need some default routing, but allow user to supply their own.
   • Optionally, keep track of lines, where they interect, modify appearance to "bridge over" crossed lines,
   • Could be tricky to know where widgets are drawn, so how do we know to route around them?
3. The connection point is circular.
   • so maybe some clipping enhancements required?
   • Or we fake it somehow.
   • or don't have circular connection points.

[vlappa]

In the Linux audio world there are besides patchmatrix (which is interesting because it uses Nuklear):

• Patchage (by drobilla)
• Patchance (based on the patchbay in Carla plugin host)

[vlappa]

Qjackctl, qpwgraph

[vlappa]

Cool, this already pretty far it seems:

https://github.com/MichaelBelousov/graphl
https://graphl.tech/graphl/demo/

Nice work! @MichaelBelousov

[MichaelBelousov]

Nice work! @MichaelBelousov

mine is not ideal but works well. I'd be happy to work on a list of things to improve!

Not sure what @david-vanderson thinks but imo nodes for dvui should be like a separate library.

[david-vanderson]

I also think the graphl stuff is really cool!

I'm not sure where to draw the line between built-in and separate. Zig's compilation model means having lots of builtins that aren't used doesn't add that much overhead, so maybe that leans us a bit more towards builtin. I guess it depends on how generic the features needed are?

@MichaelBelousov Would you mind listing some of the features you had to implement on top of dvui?

[MichaelBelousov]

Here are the ones I can think of.
Honestly there aren't that many! Also keep in mind that my project is pretty heavily based on the existing scroll area demo.

• Draw background grid
• Drag state for linking node sockets (note that my edges are just lines using dvui.pathStroke. I'm sure you could draw a bezier between the same points.
• drawing links (again you can upgrade to bezier)
• handling socket hover and drag start
• not sure if anyone needs it, but the renderNode function. I haven't done it but ideally in the future if you zoom out too much, it won't render much of the node internals