flutter_embedder VS Azul

I'm actually working on this as a side project (here).

I personally settled on Flutter. It's a modern declarative UI framework by Google that was designed for mobile apps, but it can also do desktop and web these days. It can be used as a library using its embedder API that can render to Vulkan, Metal and OpenGL. So, it can be embedded in a wgpu context (here's my prototype for that based on wgpu/Vulkan and winit). Flutter uses Dart for UI programming, which is fine for me, since a lot of iteration is necessary for that, and Flutter allows Dart code to be hot reloaded during development (so you just have to save your file and the running application is updated automatically, keeping all of its state intact). Rust wouldn't be able to do that at the moment. Web support is trivial, because Flutter Web allows integrating HTML elements between its UI layers. I can simply insert a canvas there and link that to wgpu.

Here's the repository.

I've started writing my own Flutter shell here that runs on all desktop and mobile systems Flutter supports without any platform-specific code paths. The trick is that I'm delegating the responsibility for platform-specific code to a generic library (winit in this case) and so keep it out of my codebase.

I've started a project for using Rust for a shell using the Flutter Engine's embedder interface, so it’s trivial to integrate Rust into the system. It’s available here.

What I'm currently looking into is using Flutter for UI drawing instead of web tech. It has a built-in compositing API that allows interleaving native drawing with its surfaces and has a Vulkan renderer. The only downside is that you have to write a shell for it that maps the native platform to its APIs, which is very underdocumented and needs a lot of code, for example for handling keyboard input. Here's my progress so far. It comes with shells for all of its supported platforms, but they all use OpenGL or Metal (for iOS/macOS).

I need to check out how well this combines with my Rust-based Flutter shell.

I personally spent a significant part of my spare time in the last few months researching this topic, and came to the conclusion that for my (very similar) project, I'd like to use Flutter and Dart for the UI and Rust with wgpu (maybe bevy) for the rendering backend. I'm working on an integration for native platforms (so everything except web) right now, it's available in earliest alpha here. Web itself is trivial, because you can simply mount a separate canvas as a platformview and use that for wgpu, completely separating the two worlds.

Unfortunately, I'm really busy these days so I don't have any time for any more projects. I'm currently working on this project, which allows using the UI framework Flutter together with wgpu, so I'd say that it's adjacent to your project.

Not sure what you mean but WebRender powers Firefox which definitely works on the desktop.

You can use it to build desktop UI frameworks - see for example https://azul.rs/

I'd been wanting to see this, preferably with JS being optional, and just allowing direct DOM access.

I initially thought this was what Azul was, but it's only just using Servo's WebRender compositor, and rolls its own CSS parser, DOM, and layout engine, so it doesn't benefit from most of the work done on Servo, and supports less CSS features.

https://github.com/fschutt/azul

Both Servo and Fifefox make use of webrender, which is an awesome piece of tech and is well suited to render a web page. Some GUI projects attempted to use webrender directly as well, like Azul and moxie-native

> But no one is saying, "Hey I have a CSS 2.1 compliant rasterizer and compositor that you can use in your C++ or Rust environment!" are they?

There’s actually quite a lot of interesting work going on in that general space, has been in various forms for some years. A couple that immediately spring to mind:

• Azul <https://azul.rs/> builds on WebRender, as used in Firefox. I haven’t looked at it for a few years, but it looks to have grown quite interesting now.

• Blitz <https://github.com/DioxusLabs/blitz> is based on from-scratch implementations of CSS layout and rendering, and wgpu rendering. It’s not usable yet, but is a very interesting concept. If one happens to be familiar with React Native: it’s kinda like that, or React Native Web.

Azul[1] was my solution for that, it was based on WebRender. I didn't get around to finish it in 2019, but I will work on it this year, maybe I'll get it to be mature enough to post it here.

> wide portability (at least Windoze, Linux, MacOS, iOS, Android, embedded: Azul is Windows-Linux-Mac only, don't underestimate the effort to properly port something to a new platform

> "though a Vulkan-based renderer can be made to run pretty much anywhere": WebRender is OpenGL + using software rendering as a fallback

> a permissive open source license: MPL-2.0

> a C interface/wrap to allow a wide programming language binding support: yes

> and an easily extensible and themable set of basic widgets: also yes

[1] https://azul.rs/

There is Iced which is used by system76 in Pop!_OS, Druid [DISCONTINUED], GTK-rs, Relm, Azul and Tauri. Personally I would use Tauri for its speed using the OS's native web render, documentation of use with things such as Sveltekit and the ability to make UI's using JS, CSS and HTML. Tauri similarly to Electron whilst being far faster. But its up to personal preference really. There aren't any solid "go to" options at the moment.

Sounds like you may be interested in azul not exactly servo based but on projects that originate from servo. Also this is not a typical WebView, for example it does not use HTML but uses DOM to define it's UI, and there is no JS engine in there.

Azul uses webrender. But your "glue" program is like half the web browser. You also need a vector graphics library to render websites. Webrender only does boxes, but not complex SVG paths. Once the plan was to use pathfinder, but mozilla fired the dev and they still using an old version of chromium's skia for that.

One day I'll get around to finish my library Azul [1]. Hopefully.

[1] https://azul.rs/

azul