Zoom in/out supported by default (like in blackjack)? about egui_node_graph HOT 2 CLOSED

Hi @DerLando! 😄

I'm happy to share the details of how I achieved the zoom functionality in blackjack, but unfortunately it requires a forked egui backend and it's not something that would be accepted upstream. Basically, it's a hack specific to the wgpu backend, and an ugly one at that: I have two separate egui instances, and render the second instance inside the first as a texture. This also means hijacking the winit integration and translating mouse events, plus adding a few transformations inside egui_wgpu to make sure clip rects are correct when sending them the GPU. On top of that, you need to mess with pixels_per_point at runtime, which can lead to performance issues.

This is why egui_node_graph doesn't support zoom while blackjack does. Because this is currently impossible to do without a very specific application architecture (2 separate egui instances, and a forked backend).

Egui needs a backend-independent mechanism for zooming, but I don't know enough about the egui internals to make that work. Nevertheless, I have reported this to the egui main repo and even volunteered for an implementation: With some guidance, and if someone tells me this has a chance of getting upstreamed, I'll gladly help. But so far things have been quiet.

It might help if you show your support there (even a thumbs up is okay) and expose your use case if you think that's relevant 👍

from egui_node_graph.

Thanks so much for the quick reply, I had a look at the linked feature request upstream and will add my voice.

I'll close this for now as it will likely require changes upstream.

from egui_node_graph.