Trait eframe::App

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pub trait App {
    fn update(&mut self, ctx: &Context, frame: &mut Frame);

    fn save(&mut self, _storage: &mut dyn Storage) { ... }
    fn on_close_event(&mut self) -> bool { ... }
    fn on_exit(&mut self, _gl: Option<&Context>) { ... }
    fn auto_save_interval(&self) -> Duration { ... }
    fn max_size_points(&self) -> Vec2 { ... }
    fn clear_color(&self, _visuals: &Visuals) -> Rgba { ... }
    fn persist_native_window(&self) -> bool { ... }
    fn persist_egui_memory(&self) -> bool { ... }
    fn warm_up_enabled(&self) -> bool { ... }
    fn post_rendering(&mut self, _window_size_px: [u32; 2], _frame: &Frame) { ... }
}

Expand description

Implement this trait to write apps that can be compiled for both web/wasm and desktop/native using eframe.

Required Methods

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fn update(&mut self, ctx: &Context, frame: &mut Frame)

Called each time the UI needs repainting, which may be many times per second.

Put your widgets into a egui::SidePanel, egui::TopBottomPanel, egui::CentralPanel, egui::Window or egui::Area.

The egui::Context can be cloned and saved if you like.

To force a repaint, call egui::Context::request_repaint at any time (e.g. from another thread).

Provided Methods

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fn save(&mut self, _storage: &mut dyn Storage)

Called on shutdown, and perhaps at regular intervals. Allows you to save state.

Only called when the “persistence” feature is enabled.

On web the state is stored to “Local Storage”. On native the path is picked using directories_next::ProjectDirs::data_dir which is:

Linux: /home/UserName/.local/share/APPNAME
macOS: /Users/UserName/Library/Application Support/APPNAME
Windows: C:\Users\UserName\AppData\Roaming\APPNAME

where APPNAME is what is given to eframe::run_native.

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fn on_close_event(&mut self) -> bool

Called when the user attempts to close the desktop window and/or quit the application.

By returning false the closing will be aborted. To continue the closing return true.

A scenario where this method will be run is after pressing the close button on a native window, which allows you to ask the user whether they want to do something before exiting. See the example at https://github.com/emilk/egui/blob/master/examples/confirm_exit/ for practical usage.

It will not be called on the web or when the window is forcefully closed.

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