Rust GTK4 (relm4 + libadwaita)

Build HIG-compliant GTK4 desktop apps with the relm4 Elm-style loop: message-driven, composable components with clean separation between model state and view rendering.

Core Architecture: relm4 Elm Pattern

relm4 implements an Elm-like model-update-view loop:

• Component::init() — construct initial model state + build widget tree
• Component::update() — receive a typed message, mutate model
• view! macro — declarative widget tree; auto-syncs to model on #[watch] fields

The #[relm4::component] macro generates the boilerplate; the view! macro is the widget DSL.

Key Concepts

Sync vs Async Components