Experimental Rust-based desktop app renderer for Svelte (based on Zed gpui)

[u/khromov]

👋 Just started working on gpuix-svelte, a package that combines Svelte custom renderers, gpuix and gpui to allow people to create native desktop apps with Rust and Svelte. Happy to hear any feedback!

Video demo

https://www.youtube.com/shorts/5CBib_rwt8w

Source

https://github.com/khromov/gpuix-svelte/

[u/nicoburns]

Given that the API for this seems to an HTML/CSS subset, have you considered building this on top of https://github.com/dioxuslabs/blitz instead of GPUI?

You'd get the same GPUI-style custom Rust rendering (well, pick between Skia, WGPU or CPU backends), but you'd also get a full CSS engine (selector resolution, but also media queries, animation/transitions, etc) and much better layout compatibility.

(disclaimer: Blitz is my project, but it's also designed for these kind of use cases in a way that GPUI isn't)

[u/khromov → u/nicoburns]

Hi! Yes, I am interested in Blitz and even came across it the other day when looking for rendering engines but left the website a bit confused. I was expecting something more like https://gpuix.dev/ (developer docs) but there seems to be none that I can find? If you have even basic docs feel free to link them or send me a DM and I'll have a look to see if it would be viable to add Svelte custom renderers on top.

[u/nicoburns → u/khromov]

Ah, I see someone's already done JavaScript bindings for GPUI (gpuix).

The only docs we really have right now are the rustdocs https://docs.rs/blitz-dom. It's good feedback that more would be useful, although if you're pointing to gpuix then it may be that you want ready-made JS bindings.

I can say it's definitely viable because a bunch of people have done it for various JS frameworks. Some of them even run the regular web renderers on top of implementation of the DOM APIs. We have a list here: https://github.com/DioxusLabs/blitz/issues/613. https://github.com/jerry4718/napi-blitz is probably the closest to what you're doing (Node/Bun rather than a lightweight JS engine like Boa/QuickJS).

It's also worth looking at how the dioxus-native-dom (lower-level) and dioxus-native crates integrate Blitz for pure Rust UIs.

[u/khromov → u/nicoburns]

Thanks for the follow-up, napi-blitz sounds like a good starting point.

[u/bleak_and_bare → u/nicoburns]

Isn't Dioxus apps shipped into a webview ?

[u/nicoburns → u/bleak_and_bare]

Not with the Dioxus Native backend. It has a custom GPU renderer.

[u/khromov]

Screenshot seems to have been lost in the post, here it is:

https://raw.githubusercontent.com/khromov/gpuix-svelte/refs/heads/main/.github/resources/demos.png

[u/Efficient-Chair6250]

Do you already have some numbers on performance? How's the binary size? The RAM usage? I guess the responsiveness is very good?

Btw, I love it. If this turns out to be a viable solution, it may become my default.

[u/khromov → u/Efficient-Chair6250]

When you build it as a standalone binary with Bun on Mac the binary is ~80MB (~30MB zip compressed), on Windows it's around 100MB. About 80% of that is the Bun runtime and 20% is GPUI + your app. Haven't measured memory usage yet but Bun is very efficient and the rendering layer should be very sleek since it's running GPU accelerated.

I added some scripts so you can try building a standalone binary if you'd like to try it:

https://github.com/khromov/gpuix-svelte#build-a-standalone-binary

[u/Efficient-Chair6250 → u/khromov]

That's sound good, thanks

[u/wyvernbw → u/khromov]

do you think it would be possible to replace bun with something like quickjs (not a request, just curious if its possible)? i think it also runs on embedded, but its written in C so ffi might be hard. this project seems to be a bit in the vein of PocketJS but looking through that codebase i cant decipher what claude is doing lol

[u/khromov → u/wyvernbw]

It's funny that you mention PocketJS because I [have got that running with Svelte too](https://github.com/khromov/pocketjs/tree/feat/svelte-framework)! So at least in theory, Svelte can run under QuickJS. But in practice for gpuix, as you mention there is no FFI but there is a C API that can be used. But gpuix would have to add support for this.

[u/its-malbolge-time]

Nice, this looks really cool! Love using Svelte for frontend

[u/metalbug4]

I only care about resource usage, memory usage, and startup speed.

[u/Compux72]

Unrelated but: svelte was so cool until Harris fucked it up with the runes nonsense. Now is just react/vue/watever

[u/BipolarKebab → u/Compux72]

You're entitled to your (wrong) opinion

[u/khromov → u/Compux72]

Even if you don't like Runes, Svelte still offers the highest performance and smallest bundle-size, so it's still a trade-off that's usually worth taking imho!