<h1>
<a href="https://relm4.org">
<img src="assets/Relm_logo_with_text.png" width="200" alt="Relm4">
</a>
</h1>
[](https://github.com/Relm4/Relm4/actions/workflows/rust.yml)
[](https://matrix.to/#/#relm4:matrix.org)
[](https://crates.io/crates/relm4)
[](https://docs.rs/relm4/)
[](https://relm4.org/book/stable/)
[](https://deps.rs/repo/github/Relm4/Relm4)
An idiomatic GUI library inspired by [Elm](https://elm-lang.org/) and based on [gtk4-rs](https://crates.io/crates/gtk4).
Relm4 is a new version of [relm](https://github.com/antoyo/relm) that's built from scratch and is compatible with [GTK4](https://www.gtk.org/) and [libadwaita](https://gitlab.gnome.org/GNOME/libadwaita).
## Why Relm4
We believe that GUI development should be easy, productive and delightful.
The [gtk4-rs](https://crates.io/crates/gtk4) crate already provides everything you need to write modern, beautiful and cross-platform applications.
Built on top of this foundation, Relm4 makes developing more idiomatic, simpler and faster and enables you to become productive in just a few hours.
## Our goals
+ ⏱️ **Productivity**
+ ✨ **Simplicity**
+ 📎 **Outstanding documentation**
+ 🔧 **Maintainability**
## Documentation
+ 📖 **[The Relm4 book](https://relm4.org/book/stable/)**
+ 📜 **[Rust documentation](https://docs.rs/relm4/)**
## Dependencies
Relm4 depends on GTK4: [How to install GTK4 and Rust](https://gtk-rs.org/gtk4-rs/git/book/installation.html)
## Ecosystem
+ [relm4-macros](https://crates.io/crates/relm4-macros) - several macros for declarative UI definitions.
+ [relm4-components](https://crates.io/crates/relm4-components) - a collections of reusable components.
+ [relm4-icons](https://crates.io/crates/relm4-icons) - icons for your application.
+ [relm4-template](https://github.com/Relm4/relm4-template) - a starter template for creating Relm4 applications in the Flatpak package format.
+ [relm4-snippets](https://github.com/Relm4/vscode-relm4-snippets) - code snippets to speed up your development.
Use this in to your `Cargo.toml`:
```toml
# Core library
relm4 = "0.9"
# Optional: reusable components
relm4-components = "0.9"
# Optional: icons (more info at https://github.com/Relm4/icons)
relm4-icons = "0.9.0"
```
### Features
The `relm4` crate has four feature flags:
| `macros` | Enable macros by re-exporting [`relm4-macros`](https://crates.io/crates/relm4-macros) | ✅ |
| `libadwaita` | Improved support for [libadwaita](https://gitlab.gnome.org/World/Rust/libadwaita-rs) | - |
| `libpanel` | Improved support for [libpanel](https://gitlab.gnome.org/World/Rust/libpanel-rs) | - |
| `gnome_46` | Enable all version feature flags of all dependencies to match the GNOME 46 SDK | - |
| `gnome_45` | Enable all version feature flags of all dependencies to match the GNOME 45 SDK | - |
| `gnome_44` | Enable all version feature flags of all dependencies to match the GNOME 44 SDK | - |
| `gnome_43` | Enable all version feature flags of all dependencies to match the GNOME 43 SDK | - |
| `gnome_42` | Enable all version feature flags of all dependencies to match the GNOME 42 SDK | ✅ |
The `macros` feature is a default feature.
## Examples
Several example applications are available at [examples/](examples/).
#### [📸 Screenshots from the example apps](assets/screenshots)
### A simple counter app
```rust
use gtk::prelude::*;
use relm4::prelude::*;
struct App {
counter: u8,
}
#[derive(Debug)]
enum Msg {
Increment,
Decrement,
}
#[relm4::component]
impl SimpleComponent for App {
type Init = u8;
type Input = Msg;
type Output = ();
view! {
gtk::Window {
set_title: Some("Simple app"),
set_default_size: (300, 100),
gtk::Box {
set_orientation: gtk::Orientation::Vertical,
set_spacing: 5,
set_margin_all: 5,
gtk::Button {
set_label: "Increment",
connect_clicked => Msg::Increment,
},
gtk::Button {
set_label: "Decrement",
connect_clicked => Msg::Decrement,
},
gtk::Label {
#[watch]
set_label: &format!("Counter: {}", model.counter),
set_margin_all: 5,
}
}
}
}
// Initialize the component.
fn init(
counter: Self::Init,
root: Self::Root,
sender: ComponentSender<Self>,
) -> ComponentParts<Self> {
let model = App { counter };
// Insert the code generation of the view! macro here
let widgets = view_output!();
ComponentParts { model, widgets }
}
fn update(&mut self, msg: Self::Input, _sender: ComponentSender<Self>) {
match msg {
Msg::Increment => {
self.counter = self.counter.wrapping_add(1);
}
Msg::Decrement => {
self.counter = self.counter.wrapping_sub(1);
}
}
}
}
fn main() {
let app = RelmApp::new("relm4.example.simple");
app.run::<App>(0);
}
```
## Projects using Relm4
- [fm](https://github.com/euclio/fm) — A small, general-purpose file manager.
- [Done](https://github.com/edfloreshz/done) - A simple and versatile to do app.
- [Reovim](https://github.com/songww/reovim) - GUI frontend for neovim.
- [NixOS Configuration Editor](https://github.com/vlinkz/nixos-conf-editor) - A graphical configuration editor for [NixOS](https://nixos.org).
- [Rhino Setup](https://github.com/rhino-linux/rhino-setup) - Setup wizard for [Rolling Rhino](https://rhinolinux.org/)
- [Lemoa](https://github.com/lemmy-gtk/lemoa) - Desktop client for Lemmy
- [Score Tracker](https://github.com/weclaw1/score-tracker) - App for tracking player scores in card and board games
- [Spidey](https://github.com/kdwk/Spidey) - A seamless and distraction-free work and play environment on the web
- [Toolbox Tuner](https://github.com/13hannes11/toolbox-tuner) - An application to manage Toolbx containers
- [BitRitter](https://codeberg.org/Chfkch/bitritter) - A bitwarden/vaultwarden client with mobile devices in mind
- [Space Acres](https://github.com/autonomys/space-acres) - An opinionated GUI application for farming on Autonomys Network
## License
Licensed under either of
* Apache License, Version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or http://www.apache.org/licenses/LICENSE-2.0)
* MIT license ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT)
at your option.
### Contribution
Unless you explicitly state otherwise, any contribution intentionally submitted
for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any
additional terms or conditions.
**Feedback and contributions are highly appreciated!**