frust

Frust is a Rust-native, mobile-first declarative UI framework: write one View tree in Rust and ship it to Android, iOS, macOS, Windows, Linux, and the web, rendered everywhere by the frust-owned frust-engine GPU pipeline.

frust is the facade crate. Application code depends on this single crate; it exposes run, the canonical app entry point, and curates the view, widget and reactive vocabulary from the underlying framework crates (frust-core, frust-widgets, frust-reactive, frust-theme and others).

Status: pre-1.0; APIs may change between minor versions.

Platforms

• Android and iOS
• macOS, Windows and Linux (desktop shells)
• Web (WebGPU, with a WebGL2 fallback)

Example

Add the dependency:

[dependencies]
frust = { package = "frust-ui", version = "0.6" }
frust-material = "0.6"

The package is named frust-ui and imported as frust, because the crates.io name frust belongs to another project (https://github.com/lloydmeta/frunk/issues/258). The dependency key is what frust run and frust build use to enable frust/devtools-style features: frust-cli 0.6.0 requires the key frust, while newer CLIs resolve any key, so with them frust-ui = "0.6" also works.

A counter app, the shape frust create generates. build reads as one declarative tree, and frust::app! turns the Component into the platform entry points:

use frust::{Align, Alignment, Component, CrossAxisAlignment, View, column, icon, scaffold, text};
use frust_material::{AppBarContainer, app_bar, fab, icons};

#[derive(Default)]
pub struct CounterApp;

impl Component for CounterApp {
    type State = u32;

    fn init(&self) -> u32 {
        0
    }

    fn build(&self, count: &mut u32) -> impl View<u32> {
        scaffold(Align(
            Alignment::CENTER,
            column()
                .child(text("You have pushed the button this many times:"))
                .child(text(count.to_string()).size(48.0))
                .cross_axis(CrossAxisAlignment::Center),
        ))
        .app_bar(
            app_bar::<u32>("Counter")
                .container(AppBarContainer::InversePrimary)
                .elevation(2),
        )
        .fab(Self::increment_fab())
    }
}

impl CounterApp {
    fn increment_fab() -> impl View<u32> {
        fab(icon(icons::ADD), |count: &mut u32| *count += 1).label("Increment")
    }
}

// `setup` runs once on the UI thread before the root `init`. Material 3 is the
// design system; swap in another design-system plugin's `install()` to change it.
frust::app!(
    CounterApp,
    setup = {
        frust_material::install();
    }
);

Getting started

Install the command-line tool and create a project:

cargo install frust-cli
frust create my_app

frust create writes the dependency above into the new project.

Design systems ship as separate plugin crates that an application depends on beside frust; the facade itself carries only the baseline widget set.

Links

• Documentation: https://frust.dev
• Source: https://github.com/frust-rs/frust

License

Licensed under MIT OR Apache-2.0, at your option. See LICENSE-MIT and LICENSE-APACHE in this directory.