Crate iced

source ·

Expand description

Iced is a cross-platform GUI library focused on simplicity and type-safety. Inspired by Elm.

Features

Simple, easy-to-use, batteries-included API
Type-safe, reactive programming model
Cross-platform support (Windows, macOS, Linux, and the Web)
Responsive layout
Built-in widgets (including text inputs, scrollables, and more!)
Custom widget support (create your own!)
Debug overlay with performance metrics
First-class support for async actions (use futures!)
Modular ecosystem split into reusable parts:
- A renderer-agnostic native runtime enabling integration with existing systems
- A built-in renderer supporting Vulkan, Metal, DX11, and DX12
- A windowing shell
- A web runtime leveraging the DOM

Check out the repository and the examples for more details!

Overview

Inspired by The Elm Architecture, Iced expects you to split user interfaces into four different concepts:

State — the state of your application
Messages — user interactions or meaningful events that you care about
View logic — a way to display your state as widgets that may produce messages on user interaction
Update logic — a way to react to messages and update your state

We can build something to see how this works! Let’s say we want a simple counter that can be incremented and decremented using two buttons.

We start by modelling the state of our application:

struct Counter {
    // The counter value
    value: i32,
}

Next, we need to define the possible user interactions of our counter: the button presses. These interactions are our messages:

#[derive(Debug, Clone, Copy)]
pub enum Message {
    IncrementPressed,
    DecrementPressed,
}

Now, let’s show the actual counter by putting it all together in our view logic:

use iced::widget::{button, column, text, Column};

impl Counter {
    pub fn view(&mut self) -> Column<Message> {
        // We use a column: a simple vertical layout
        column![
            // The increment button. We tell it to produce an
            // `IncrementPressed` message when pressed
            button("+").on_press(Message::IncrementPressed),

            // We show the value of the counter here
            text(self.value).size(50),

            // The decrement button. We tell it to produce a
            // `DecrementPressed` message when pressed
            button("-").on_press(Message::DecrementPressed),
        ]
    }
}

Finally, we need to be able to react to any produced messages and change our state accordingly in our update logic:

impl Counter {
    // ...

    pub fn update(&mut self, message: Message) {
        match message {
            Message::IncrementPressed => {
                self.value += 1;
            }
            Message::DecrementPressed => {
                self.value -= 1;
            }
        }
    }
}

And that’s everything! We just wrote a whole user interface. Iced is now able to:

Take the result of our view logic and layout its widgets.
Process events from our system and produce messages for our update logic.
Draw the resulting user interface.