Guide Getting Started

Getting Started

By the end of this chapter you'll have a ROSACE app running in a window.

Prerequisites

• Rust (stable) — install via rustup.
• For web/mobile later: the wasm32-unknown-unknown target, Xcode (iOS), or the Android SDK/NDK. Not needed for desktop.

The rsc CLI

ROSACE ships a developer CLI, rsc, that wraps cargo and adds the app-framework workflow: scaffolding, a dev loop with hot reload, and multi-platform build/run. Install it from the repo:

# from the ROSACE repo root
cargo install --path rosace-cli
rsc --help

rsc uses cargo under the hood for desktop; it adds the toolchains for web (wasm), iOS (xcodebuild), and Android (gradle) on top. Run rsc doctor to check your toolchain, and rsc devices to list simulators/devices.

Your first app

Create a new app:

rsc new my-app
cd my-app

Then run it:

rsc dev          # dev mode: runs the app with hot reload on
# or
rsc run          # build + run once (release-style, no hot reload)

rsc dev builds and launches the app, watches your src/, and hot-reloads view! changes live (see the Hot Reload chapter). rsc run just builds and runs.

The anatomy of an app

Every ROSACE app is a Component you hand to App::launch:

use rosace::prelude::*;

struct App0;

impl Component for App0 {
    fn build(&self, _ctx: &mut Context) -> Element {
        Scaffold::new(
            Column::new()
                .padding(EdgeInsets::all(24.0))
                .child(Text::new("It works!")),
        )
        .into_element()
    }
}

fn main() {
    App::new().title("My App").size(480, 320).launch(App0);
}

• impl Component with a build method is the whole contract — you return the UI as an Element tree.
• Scaffold gives you the standard screen frame (optional app bar, body, etc.).
• Column stacks children vertically; Text renders text; .into_element() turns a widget into the Element the framework expects.
• App::new()...launch(...) opens the window and starts the frame loop.

Running the examples

The repo ships runnable examples you can learn from:

cargo run -p rosace-examples --bin widget_gallery
cargo run -p rosace-examples --bin markdown_editor_demo

Next: Components & State — the two ideas everything else is built on.