Renderer as a child inside another window

[andreiltd]

Hello 👋

Is it possible to integrate Freya for UI development within an application that is built on winit, similar to the way wry allows the creation of child webviews? Specifically, I'm interested in understanding if Freya can be used to design 2D menus or interfaces within a game application which owns the window and event loop.

[marc2332]

Hey Tomasz!

I think it could be possible, although I have never attempted anything as that. Freya depends on some Skia APIs, so it's not exactly graphics-agnostic, perhaps that is not a problem.

Freya at its core is event loop-agnostic, so it should be possible to integrate it into another winit app. It even has a headless testing runner that simulates an event loop and platform inputs (like cursor movement, and that stuff), so, my point is that it would only need to be integrated properly. Perhaps getting skia to work on top is the most difficult part? I am not sure

[felipetesc]

Hello. I'm just guessing here, but I think, child webviews, alert dialogs, and the such, are actually something related to winit itself(as you stated) and how to integrate to Freya. Here we can find an example of multi windows: https://github.com/rust-windowing/winit/blob/master/examples/multiwindow.rs. So, perhaps, if there is high level way to coordinate multi windows manageament, using for example, use_state, and use_signal, and the event bubbling, it will be possible. About the menubar, this Rust crate, could help https://lib.rs/crates/menubar, although I donno the current state of it.

[marc2332]

No, there is no HTML, wry was simply an example on how they integrate multiple GUIs in the same window.

[andreiltd]

I did some initial research and it should be doable via Skia by setting translation matrix on canvas:

let matrix = Matrix::translate(Vector::new(100.0, 100.0));
canvas.set_matrix(&matrix);

which causes the coordinate system to be shifted such that the point (100, 100) in the original coordinate system is now treated as the origin (0, 0) so any drawing will be shifted as well. This would, hopefully, allow to create subregion for drawing.

[marc2332]

Sorry for late reply. Yes, that would move the rendering wherever you want, but it would break the event system as freya would still think the elements are wherever they were in the first place, so events would also need to be translated to the new coordinates

[felipetesc]

With this event system changes, and more tweaks, would be possible to use Freya with webgl (wasm), Fyrox, SDL Canvas, and so own ?

[marc2332]

Everything is possible with enough tweaks, Freya could run in wasm "easily" as Skia supports web, but,running Freya under Fyrox or other renderers would require making Freya renderer-agnostic, which isn't currently the case as it's "highly" integrated with Skia