I've been doing something similar to this, except with go. In my case I have a flutter frontend and a go backend that's built using go mobile. Instead of trying to figure out how to make all of my go functions use data types that are supported by the various native frameworks, I've opted to use protobuf objects for every type that is shared between the frontend and backend. This way I can expose a single go function via the flutter FFI that takes in a binary array and then converts it to a protobuf object. This gives me a nice separation of concerns between my business logic and frontend while also providing easy to use objects for the front and backend.
Not sure that I'd recommend this approach to everyone. Protobuf code generation can be finicky to set up, but I'm doing it so that I can access go's rich array of libraries in my app.
My music model is all Protobuf messages, which go from Dart/Flutter land to Kotlin/C/Swift/JS audio backends on target platforms. I also use Protobuf for saving and sharing. It’s been incredibly resilient and performant.
the__alchemist 1 hours ago [-]
Hah yea. I just did a deep dive into protobufs and RPC for an embedded application. Left learning a lot, and with a headache. Part of it was because this was using heapless, and I got errors until I configured the generator to use the right Vec sizes.
nu11ptr 51 minutes ago [-]
Have you considered just using gRPC in this case? You gain 100% language separation (no FFI) and remote client/server at the cost of a little more call overhead.
klabb3 43 minutes ago [-]
Not OP but in same situation. Not every platform can run gRPC over localhost easily or without extra privileges.
I used to use protobuf but now I just use JSON, over stdin/stdout on desktop. It’s honestly quite good.
cyberax 31 minutes ago [-]
Why not ConnectRPC? It's basically gRPC but without all the strange requirements for exotic HTTP features.
turtlebro 1 hours ago [-]
That's a perfectly fine approach, Protobuf strength is exactly these kind of use cases.
merksoftworks 5 hours ago [-]
So egui is great for projects where the application runtime is short lived, or for overlays in longer lived projects. The visual equivalent of scripts, where you know you need a small amount of immediate visual feedback and tweaking parameters for it to be useful to the end user.
Flutter answers questions about more robust UI.
It's good that you chose the right tool for the job and more people should know that there are options. But fundamentally I'm most motivated by the possibility of a robust UI framework made from first principles to be as low friction as egui but with the accessibility, performance, and visual flexibility of stylable retained mode guis.
Raph Levien and the xilem project might be getting us closer.
piker 4 hours ago [-]
Both approaches have their downsides and, in my view, retained mode and immediate mode tend to converge as the UI complexity increases. So far, no problems with implementing any UI I want in my experience with egui on a somewhat complicated application (Desktop word processor). Immediate mode is a breath of fresh air from React.
[Edit: although the standard accessibility criticisms apply to my application; although that's more of an issue with my implementation than an indictment of immediate mode generally.]
nopelynopington 23 minutes ago [-]
I'm also thinking of building a word processor so I'd be interested to see what you're working on if you fancy sharing?
the__alchemist 1 hours ago [-]
I'm curious too. I currently have both a plasmid editor, and protein/molecule viewer using EGUI. Both have complex UIs, and I haven't hit roadblocks. I think the protein viewer might be more of a canonical immediate-mode case, because most of the window is a 3D render, but it still has a GUI above it.
Aeolun 4 hours ago [-]
If your UI is fast enough, why not in complex UI’s either? I’d say it gives you good motivation to keep your UI handling code as fast as possible.
mort96 4 hours ago [-]
Doesn't egui always re-render? I like my idle apps to be doing nothing, I don't want them running their render loop in the background
the__alchemist 1 hours ago [-]
I think the default behavior is to only re-render if the window is active/focused. You can trigger a render at specific points, including in the main loop, which will result in the behavior you mention.
This can be problematic, e.g. some of the sensor interfaces I have, I want to always display correct data, even if not focused. So, I have to decide if I want to have old data shown in the background misleading users, or have a per penalty from constant renders. Or try something else to be clever. (Maybe have it update at a low rate if not focused? I think that's the move...)
user____name 4 hours ago [-]
Any quarter decent imgui implementation will idle when there's no input or active animations, and the renderer can generate dirty tiles or rects to unnecessary redrawing -- if it matters, gpus are ridiculously overpowered for drawing a bunch of rectangles. Ui logic is usually firmly in the microseconds realm.
mort96 4 hours ago [-]
I agree that this is not a necessary downside to immediate mode GUIs, but we're talking about egui specifically here. AFAIK, egui always redraws at some relatively high rate even when nothing is happening. (I'm having trouble finding documentation about what that rate is though.)
Boxxed 6 minutes ago [-]
That's not true, it only re-renders if there's an input event or an animation running. This is very easy to see if you just put a `println!` in your UI logic.
> egui only repaints when there is interaction (e.g. mouse movement) or an animation, so if your app is idle, no CPU is wasted.
pixelpoet 2 hours ago [-]
I really wish this were built into imgui as a first-class use case instead of requiring a hodgepodge mix of unofficial hacks.
I recall the author posting an imgui update saying this will be an officially supported mode, but AFAIK it's still not the case. Otherwise I would be building all my applications with imgui going forward.
Re-rendering the screen, even if it's fast, incurs a lot of memory bandwidth to draw everything and swap framebuffers etc. Not something you'd like to happen on mobile, in particular. Just because the waste is "small", doesn't mean it's acceptable.
freefrog1234 3 hours ago [-]
By default it re-renders on each event. This isn't often on mobile apps, but moving a mouse across a desktop app triggers multiple vents. There is a function call to request a re-render if you want not to wait for an event.
mort96 3 hours ago [-]
So if it's just an idle visible application, does it not render at all because there are no events? Or am I right that there's some idle redrawing going on
Philpax 3 hours ago [-]
With eframe, it does not re-render when idle, no. You need to have another thread that forces it to redraw on your own schedule. It will also redraw when an event occurs (mouse movement, keyboard presses, interacting with the application in general.)
baq 4 hours ago [-]
do you run without a compositor? I get where you're coming from, but 'idle' can mean a lot of different things and redrawing the whole UI at 60hz is not necessarily 'not idle' nowadays.
mort96 4 hours ago [-]
I run with a compositor, which is exactly why it's so great for the application to just draw its window once and then the compositor has the window's contents as a texture. The compositor can do whatever it wants with that texture without involvement from the application.
strogonoff 5 hours ago [-]
Immediate mode GUIs are cool but it seems that accessibility support is somewhat lacking. In native frameworks you often get it for free, on the Web you can follow ARIA and get it for free, but with immediate mode GUIs it seems that it is always a bit of an afterthought. For example, it seems that egui supports AccessKit, but not when used on the Web. With Dear ImGui it seems worse, there is some effort in that direction but tickets about accessibility are open (this is based on a quick scan, I may be wrong).
I guess it makes sense since immediate mode focuses on speed and applications like games, but if only there was best of both worlds.
Philpax 3 hours ago [-]
The lack of accessibility on the web is less an immediate mode problem and more of a problem with eschewing the web's native UI stack and rendering everything yourself. There are ways to signal to the browser what the content of your custom rendering is, but they very much do not come for free and require much more integration than AccessKit does on native.
zigzag312 4 hours ago [-]
Is there any technical limitation that accessibility support is usually lacking in immediate mode GUIs? Or it's just a lot of work?
Flutter, which does its own rendering of controls, needs to implement a lot of accessibility features by itself.
baq 4 hours ago [-]
'a lot of work' is probably an understatement. one of the reasons everybody embeds browsers nowadays is all the text rendering quirks (e.g. right-to-left) are solved - and some of it includes accessibility (like easy theming, scaling, aria, screen reader support, etc.) browsers spent a lot of resources to make this happen.
lazypenguin 1 hours ago [-]
There’s a big advantage to having your whole application in one language. I’m not sure the experience of egui on mobile though but egui is great to use as a developer
Pros
- Solid widget set
- Easy to get started
- Less state management
- Easy to make custom widgets
- Active community and crates (e.g docking view, tables, etc.)
- Fast to build new Ui
Cons
- Harder to do layouts (has multipass and some flexbox crates but still hard and compile loop makes it slow to iterate)
- Bring your own architecture (no restrictions on how you build your app so easy to make spaghetti if you’re not careful)
Egui is currently my favorite Rust UI crate although Slint and iced are also interesting.
> A quick Google search with "flutter setstate is not refreshing" reveals a struggle that you will face quite often when running Flutter. It sounds like an easy fix, but the nature of Flutter using a bunch of nested Widgets creates, naturally, lasagna code that makes it hard to reason about this.
Can you expand on this OP? I've never had problems with `setState` nor "lasagna code" in Flutter. From a quick search I mostly seem to find questions from people who are still learning Flutter and getting basic things wrong.
rossant 2 hours ago [-]
I really like the immediate mode GUI (IMGUI) paradigm. The other day, I looked into whether any web-based IMGUI libraries existed. It seems that HTML and the DOM are designed so differently from IMGUI that such an approach doesn't really make sense, unfortunately, unless everything is rendered manually in a canvas, WebGL, or WebGPU, which brings its own set of challenges.
ar-nelson 2 hours ago [-]
I really like Mithril.js (https://mithril.js.org/), which is, IMO, as close as it gets to web IMGUI. It looks a lot like React, but rendering happens manually, either on each event or with a manual m.redraw() call.
k__ 23 minutes ago [-]
I think, similar to Preact, Mithril skips the VDOM, which makes it "more immediate" than React.
However, updating the DOM and then turning the DOM to an image (i.e., rendering it) still has an indirection that using canvas/webgl/etc. don't have.
edflsafoiewq 2 hours ago [-]
Isn't that basically what VDOM is?
k__ 26 minutes ago [-]
A virtual DOM is another indirection, so the opposite of what immediate mode tries to accomplish.
edflsafoiewq 24 minutes ago [-]
Immediate mode only describes the interface.
k__ 20 minutes ago [-]
Does it?
I had the impression that the lack of double buffering would imply a more direct access, this the "immediate" in the name.
airstrike 3 hours ago [-]
I feel obliged to mention that iced is a fantastic Rust GUI library for more complex applications:
Since others are sharing Rust GUI libraries, I’ll mention Slint [https://slint.rs] a native GUI toolkit written Rust. It has a declarative domain specific languages, editor tools, and has been stable with no breaking API changes since 2023. I'm one of the developers.
mtndew4brkfst 1 hours ago [-]
Anyone considering it will need to decide for themselves how to feel about it, but I think it's important to prospective users to highlight that the current licensing model for Slint requires either GPL3-compatible licensing of your work, advertising for Slint within your own software, or paying ongoing licensing fees and/or royalties.
I only mention this because those constraints are notably more restrictive than the vast majority of the Rust crate ecosystem.
I take no particular stance on whether this is a fair or good practice or about the technical suitability of Slint beyond this concern, I just think it's a hurdle for most people so they should be made aware early and often.
the__alchemist 59 minutes ago [-]
I love how y'all target embedded. I love EGUI for PC applications, but will try Slint next time I'm doing an embedded device that has a display.
feverzsj 5 hours ago [-]
I still prefer good old GUI frameworks with WYSIWYG designers.
jeroenhd 5 hours ago [-]
I think Slint is getting pretty close to that these days: https://slint.dev/
No quick and easy drag&drop just yet, but IDE support for live preview rendering makes it come pretty close. I do long for the Visual Studio GUI design days, but things aren't as barebones anymore as they used to be in open source Rust land.
jenadine 3 hours ago [-]
WYSIWYG designers seem convenient, but they're not that popular anymore for a reason. Writing UI in code is more flexible, easier to maintain, and works better as projects grow.
alkonaut 1 hours ago [-]
WYSIWYG doesn't necessarily mean you are limited to using some designer and can't edit code. It's enough (and better) to have a live preview, than a full designer. It just means you see live what the code does, at the point when you write it, not later when you run it.
When hand-writing XAML or similar, it's great to see the UI created live. Like editing markdown and seeing the preview, versus editing markdown and not seeing the preview.
alerighi 3 hours ago [-]
In the end the WYSIWYG would produce an XML file that you can put under version control. All depends on the UI of the thing your are building, if what you are building only needs to be functional and nobody cares about the UI (that is always the case of internal use software, that needs to have a good UX but who cares if it has the Windows 95 style controls, like machine HMIs, ERP software, etc.) WYSIWYG (like Visual Studio) are good to write things fast and typically with a consistent layout.
I mean, most companies are not building a videogame, and most people are still fine using things like AS/400, so...
jenadine 2 hours ago [-]
But those files are often hard to read and merge.
If WYSIWYG really worked well, why aren't more big projects or popular frameworks using it? Why do you think it's become less popular over time?
mattmanser 2 hours ago [-]
Because editors stopped trying to do WYSIWYG. It's not that the demand isn't there. They stopped trying about the time monitors went from a couple of quite similar fixed widths of 600/768 to more. Then smart phones came along and really killed the WYSWIG editor. I worked with Silverlight for a year in the late 2000s, and even by then WYSWYG editors were struggling. You sorta still had some for flash and stuff. They were trying to bring back a WYSWIG editor for it (and for WPF in general after silverlight flopped). But it was pretty clunky still. There's a lot of hard problems about how you anchor elements, how things scale, that are much easier to express in code than in a properties panel.
You can see the demand in the sheer number of WYSWYG editors for the web.
But for development, basically all the big players stopped trying or died for other reasons. I just think no-one's got the will to try it.
I think it could be a huge opportunity for someone. Right now, with AI coming to the fore in development, seems to be when it would become absolutely killer for less code orientated people making their own apps by adding/dragging controls around and telling an AI what each control should do. All without a programmer involved. The AI could even "solve" the hard problem of a good responsive WYSWYG editor by making assumptions of how the user probably wants the controls anchored.
So I think that's the market we'll see a WYSWIG editor emerge again for.
wdroz 5 hours ago [-]
I also prefer the mental model of immediate mode, but when I played with Dioxus[0] for a rust fullstack hobby project[1], I was able to adapt.
I liked the DX with the tools and the `rsx!` macro. The use of `#[cfg(feature = "server")]` to define server-side code is interesting, it lets you keep a shared codebase for frontend and backend, while still controlling what gets compiled to WASM for the client.
I actually wanted to ask you about this at our last meetup (Rust Aarhus), so nice to see it on hackernews. It did seem you switched away from flutter. ;)
How is shipping egui apps vs flutter. I'd imagine that especially shipping a rust integration with Flutter might be a bit of a pain
voat 41 minutes ago [-]
I've personally been really impressed with gpui from the Zed folks.
dark__paladin 1 hours ago [-]
I'm not a UI dev but I have messed with Qt some. Does egui or some other rust framework the same native look that Qt does?
Not sure that I'd recommend this approach to everyone. Protobuf code generation can be finicky to set up, but I'm doing it so that I can access go's rich array of libraries in my app.
My music model is all Protobuf messages, which go from Dart/Flutter land to Kotlin/C/Swift/JS audio backends on target platforms. I also use Protobuf for saving and sharing. It’s been incredibly resilient and performant.
I used to use protobuf but now I just use JSON, over stdin/stdout on desktop. It’s honestly quite good.
Flutter answers questions about more robust UI.
It's good that you chose the right tool for the job and more people should know that there are options. But fundamentally I'm most motivated by the possibility of a robust UI framework made from first principles to be as low friction as egui but with the accessibility, performance, and visual flexibility of stylable retained mode guis.
Raph Levien and the xilem project might be getting us closer.
[Edit: although the standard accessibility criticisms apply to my application; although that's more of an issue with my implementation than an indictment of immediate mode generally.]
This can be problematic, e.g. some of the sensor interfaces I have, I want to always display correct data, even if not focused. So, I have to decide if I want to have old data shown in the background misleading users, or have a per penalty from constant renders. Or try something else to be clever. (Maybe have it update at a low rate if not focused? I think that's the move...)
This is also mentioned in the gui docs here https://github.com/emilk/egui#why-immediate-mode:
> egui only repaints when there is interaction (e.g. mouse movement) or an animation, so if your app is idle, no CPU is wasted.
I recall the author posting an imgui update saying this will be an officially supported mode, but AFAIK it's still not the case. Otherwise I would be building all my applications with imgui going forward.
Re-rendering the screen, even if it's fast, incurs a lot of memory bandwidth to draw everything and swap framebuffers etc. Not something you'd like to happen on mobile, in particular. Just because the waste is "small", doesn't mean it's acceptable.
I guess it makes sense since immediate mode focuses on speed and applications like games, but if only there was best of both worlds.
Flutter, which does its own rendering of controls, needs to implement a lot of accessibility features by itself.
Pros
- Solid widget set
- Easy to get started
- Less state management
- Easy to make custom widgets
- Active community and crates (e.g docking view, tables, etc.)
- Fast to build new Ui
Cons
- Harder to do layouts (has multipass and some flexbox crates but still hard and compile loop makes it slow to iterate)
- Bring your own architecture (no restrictions on how you build your app so easy to make spaghetti if you’re not careful)
Egui is currently my favorite Rust UI crate although Slint and iced are also interesting.
https://github.com/iced-rs/iced/pull/3000
Can you expand on this OP? I've never had problems with `setState` nor "lasagna code" in Flutter. From a quick search I mostly seem to find questions from people who are still learning Flutter and getting basic things wrong.
However, updating the DOM and then turning the DOM to an image (i.e., rendering it) still has an indirection that using canvas/webgl/etc. don't have.
I had the impression that the lack of double buffering would imply a more direct access, this the "immediate" in the name.
https://iced.rs
https://github.com/slint-ui/slint/blob/master/FAQ.md#licensi...
I only mention this because those constraints are notably more restrictive than the vast majority of the Rust crate ecosystem.
I take no particular stance on whether this is a fair or good practice or about the technical suitability of Slint beyond this concern, I just think it's a hurdle for most people so they should be made aware early and often.
No quick and easy drag&drop just yet, but IDE support for live preview rendering makes it come pretty close. I do long for the Visual Studio GUI design days, but things aren't as barebones anymore as they used to be in open source Rust land.
When hand-writing XAML or similar, it's great to see the UI created live. Like editing markdown and seeing the preview, versus editing markdown and not seeing the preview.
You can see the demand in the sheer number of WYSWYG editors for the web.
But for development, basically all the big players stopped trying or died for other reasons. I just think no-one's got the will to try it.
I think it could be a huge opportunity for someone. Right now, with AI coming to the fore in development, seems to be when it would become absolutely killer for less code orientated people making their own apps by adding/dragging controls around and telling an AI what each control should do. All without a programmer involved. The AI could even "solve" the hard problem of a good responsive WYSWYG editor by making assumptions of how the user probably wants the controls anchored.
So I think that's the market we'll see a WYSWIG editor emerge again for.
I liked the DX with the tools and the `rsx!` macro. The use of `#[cfg(feature = "server")]` to define server-side code is interesting, it lets you keep a shared codebase for frontend and backend, while still controlling what gets compiled to WASM for the client.
[0] -- https://dioxuslabs.com/
[1] -- https://blazingboard.ch/ (not mobile friendly, sorry)
How is shipping egui apps vs flutter. I'd imagine that especially shipping a rust integration with Flutter might be a bit of a pain
Non-goals
* Become the most powerful GUI library
* Native looking interface
valgrind --leak-check=full --show-reachable=yes --track-origins=yes -s ./your_program
is memory leak?