# relm4

**Repository Path**: lluo/relm4

## Basic Information

- **Project Name**: relm4
- **Description**: No description available
- **Primary Language**: Unknown
- **License**: MIT
- **Default Branch**: main
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2021-09-05
- **Last Updated**: 2024-05-29

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

<h1>
  <img src="assets/Relm_logo_with_text.svg" height="65" alt="Relm4">
</h1>

[![CI](https://github.com/AaronErhardt/relm4/actions/workflows/rust.yml/badge.svg)](https://github.com/AaronErhardt/relm4/actions/workflows/rust.yml)
[![Matrix](https://img.shields.io/matrix/relm4:matrix.org?label=matrix%20chat)](https://matrix.to/#/#relm4:matrix.org)
[![Relm4 on crates.io](https://img.shields.io/crates/v/relm4.svg)](https://crates.io/crates/relm4)
[![Relm4 docs](https://img.shields.io/badge/rust-documentation-blue)](https://aaronerhardt.github.io/docs/relm4/relm4/)
[![Relm4 book](https://img.shields.io/badge/rust-book-fc0060)](https://aaronerhardt.github.io/relm4-book/book/)
![Minimum Rust version 1.53](https://img.shields.io/badge/rustc-1.53+-06a096.svg)

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).

## Goals

+ ⏱️ **Productivity:** Writing Relm4 applications should be intuitive and efficient
+ ⚡ **Flexibility:** Anything that’s possible in GTK4 should work well in Relm4, too
+ ✨ **Simplicity:** Writing applications should be as easy and straightforward as possible
+ 🔧 **Maintainability**: The Elm programming model used by Relm4 provides a simple and clear structure for app development

## Documentation

+ 📖 **[Book](https://aaronerhardt.github.io/relm4-book/book/)**
+ 📜 **[Rust documentation](https://aaronerhardt.github.io/docs/relm4/relm4/)**

## Dependencies

Relm4 only depends on GTK4: [How to install GTK4](https://www.gtk.org/docs/installations/)

## Ecosystem

Relm4 has two crates that extend the core functionality:

+ [relm4-macros](https://crates.io/crates/relm4-macros) provides a `widget` macro that simplifies UI creation
+ [relm4-components](https://crates.io/crates/relm4-components) is a collections of reusable components you can easily integrate into your application

Add this to your `Cargo.toml`:

```toml
gtk = { version = "0.2", package = "gtk4" }
relm4 = "0.1"
relm4-macros = "0.1"
relm4-components = "0.1"
```

### Features

The relm4 crate has two feature flags:

+ tokio-rt: Adds the `AsyncWorker` type that uses an async update function
+ libadwaita: Improved support for [libadwaita](https://gitlab.gnome.org/World/Rust/libadwaita-rs)

## Examples

Several example applications are available at [relm4-examples/](relm4-examples/).

#### [📸 Screenshots from the example apps](assets/screenshots)

### A simple counter app

![Simple app screenshot light](assets/screenshots/simple-light.png)
![Simple app screenshot dark](assets/screenshots/simple-dark.png)

```rust
use gtk::prelude::{BoxExt, ButtonExt, GtkWindowExt, OrientableExt};
use relm4::{send, AppUpdate, Model, RelmApp, Sender, WidgetPlus, Widgets};

#[derive(Default)]
struct AppModel {
    counter: u8,
}

enum AppMsg {
    Increment,
    Decrement,
}

impl Model for AppModel {
    type Msg = AppMsg;
    type Widgets = AppWidgets;
    type Components = ();
}

impl AppUpdate for AppModel {
    fn update(&mut self, msg: AppMsg, _components: &(), _sender: Sender<AppMsg>) -> bool {
        match msg {
            AppMsg::Increment => {
                self.counter = self.counter.wrapping_add(1);
            }
            AppMsg::Decrement => {
                self.counter = self.counter.wrapping_sub(1);
            }
        }
        true
    }
}

#[relm4_macros::widget]
impl Widgets<AppModel, ()> for AppWidgets {
    view! {
        gtk::ApplicationWindow {
            set_title: Some("Simple app"),
            set_default_width: 300,
            set_default_height: 100,
            set_child = Some(&gtk::Box) {
                set_orientation: gtk::Orientation::Vertical,
                set_margin_all: 5,
                set_spacing: 5,

                append = &gtk::Button {
                    set_label: "Increment",
                    connect_clicked(sender) => move |_| {
                        send!(sender, AppMsg::Increment);
                    },
                },
                append = &gtk::Button {
                    set_label: "Decrement",
                    connect_clicked(sender) => move |_| {
                        send!(sender, AppMsg::Decrement);
                    },
                },
                append = &gtk::Label {
                    set_margin_all: 5,
                    set_label: watch! { &format!("Counter: {}", model.counter) },
                }
            },
        }
    }
}

fn main() {
    let model = AppModel::default();
    let app = RelmApp::new(model);
    app.run();
}

```

## 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!**