facet_runtime

Facet's application entry point. App::run installs the target backend; apps register windows and each window definition can register content routes.

import "facet_runtime/runtime" as runtime;
import "facet/screen" as screen;

fn main() -> i32 {
    let app = runtime::App::new("Notes");
    let main = app.window("main", home_factory,
        chrome: screen::Chrome::new(title: "Notes"));
    main.route("editor", editor_factory);
    let result = app.run("main");
    if result.is_ok() { return 0; }
    return 1;
}

Factories return screen::ScreenBox. Window title, size, and controls come from registration; screens receive nav::Context and nav::State hooks.

From a screen or component action, use runtime::app() to retrieve the running app: runtime::app().open_window("model_library"). Register that window during setup. No global app storage or windows::install(app) helper is needed. App::new(...) creates another app; it does not retrieve the current one. See app access and platform availability.

open_window(name, key:) creates or activates a window instance; find_window(name, key:) retrieves it without activation. Both return Option[window::Window]. w.nav() owns that instance's routes and history. Closing a window disposes its content and history. Opening another window never becomes content navigation. Desktop and mobile apps explicitly compose shared screens for their platform.

The alternate run, run_component, run_screen, and present_window functions and the runtime::Window interface have been removed. Use app.window(...) and app.run(...) for demos as well as applications.

runtime_macos, runtime_linux, runtime_windows, runtime_ios, and runtime_android install their backends.

Windows: WinUI, and the Win32 opt-out

runtime_windows runs the app on WinUI (facet_winui), the Windows backend (netdu/cplus#20). An app names no backend; its manifest lists facet_runtime's Windows closure:

[windows.dependencies]
facet_winui = "*"
winui       = "*"
winrt       = "*"
win32       = "*"   # the shell services: clipboard and file pickers

A plain cpc build output runs wherever the Windows App Runtime 2 is installed; see facet_winui's Deployment.

WinUI serves the whole facade surface App uses: one native window per open_window (sessions opened before launch are queued until the XAML Application starts, and timers scheduled before launch are armed then), screen::Chrome (size, minimum/maximum, bar, buttons), runtime::alert / choose / prompt / alert_blocking as keyed facet sheets on the window that asked (alert:title, alert:primary, ...), the window verbs, frame/density/ activity reads and the active/inactive/size/density observers. Closing the last window ends run. A user close (caption button, Alt+F4) asks the window's on_should_close, and closing the last window also asks on_should_quit, as app.quit() does. App::menu is a MenuBar in every window, its keys Ctrl shortcuts, and facet_agent serves every window through one connection - see facet_winui's MANIFEST. The clipboard and the file and folder pickers are src/shell_windows.cplus, over win32, whichever backend draws. When WinUI cannot start (no runtime), run answers InvalidInput with a message naming the installer.

The deprecated Win32 backend stays reachable as an explicit opt-out until it is removed:

import "facet_runtime/win32" as win32;   // Windows only: there is no base file
win32::select();                          // before app.run(...)

The app that does this lists facet_win32 beside the closure above. An app that never imports facet_runtime/win32 never compiles facet_win32: runtime_windows reaches it only through a seam (runtime::Backend, filled by select()). For that reason this package is source mode on Windows ([windows.build] prebuild = false): a prebuilt archive is compiled from every active module, win32_windows included. facet_runtime/winui's select(), the old WinUI opt-in, still exists and does nothing.

examples/facet_runtime_winui is a two-window app on WinUI; examples/facet_runtime_win32 takes the opt-out. The neutral runtime reports no backend. Shared window ownership lives in windows.cplus; retained content navigation lives in facet/navigation.

See the navigation guide and migration table and the API reference. Run cpc test --filter facet_runtime from this package to test the active platform facade and native window ownership.