Trait Panel 

pub trait Panel {
    // Required methods
    fn title(&self) -> &str;
    fn ui(&mut self, ui: &mut Ui);
    fn state_json(&self) -> Value;
    fn update_json(&mut self, msg_json: &str);
}

One pane, host-/backend-agnostic. The single seam every UI pane implements.

It is object-safe (Box<dyn Panel> is the currency the deck/host holds), and it mirrors Facet’s four core methods so the blanket impl below makes every Facet a Panel.

Required Methods

fn title(&self) -> &str

Tab label / panel heading.

fn ui(&mut self, ui: &mut Ui)

Paint into the live egui frame. Backends: native paints directly; the native cross-host adapter forwards to the guest pane’s own ui; the wasm backend paints a decoded display-list; headless paints nothing.

fn state_json(&self) -> Value

FC-3 observable state — the common currency for tests + the web state-hook.

fn update_json(&mut self, msg_json: &str)

The Elm mutation path — apply one message (JSON). Used by the headless drive + robotui, and by the wasm/adapter backends to route host-side input.

Dyn Compatibility

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors

impl<T: Facet + ?Sized> Panel for T

Backend (1): native in-process. The blanket impl that makes every facett Facet a Panel with zero per-facet code. It forwards each of the four Panel methods to the identically-shaped Facet method (the update_json default landed on Facet for exactly this convergence). There is no boundary, no serialize, no wasm toolchain — this is what a pane runs in its own app’s desktop client, the common case for every inventoried pane.