80 lines
2.8 KiB
Rust
80 lines
2.8 KiB
Rust
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//! Traits and helper for writing Egui apps.
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//!
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//! Egui can be used as a library, but you can also use it as a framework to write apps in.
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//! This module defined the `App` trait that can be implemented and used with the `egui_web` and `egui_glium` crates.
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use crate::Ui;
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/// Implement this trait to write apps that can be compiled both natively using the `egui_glium` crate,
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/// and deployed as a web site using the `egui_web` crate.
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pub trait App {
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/// Called each time the UI needs repainting, which may be many times per second.
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fn ui(&mut self, ui: &mut Ui, backend: &mut dyn Backend);
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/// Called once on shutdown. Allows you to save state.
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fn on_exit(&mut self, _storage: &mut dyn Storage) {}
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}
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// TODO: replace with manually calling `egui::Context::request_repaint()` each frame.
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/// How the backend runs the app
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#[derive(Clone, Copy, Debug, Eq, PartialEq)]
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pub enum RunMode {
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/// Rapint the UI all the time (at the display refresh rate of e.g. 60 Hz).
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/// This is good for games where things are constantly moving.
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/// This can also be achieved with `RunMode::Reactive` combined with calling `egui::Context::request_repaint()` each frame.
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Continuous,
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/// Only repaint when there are animations or input (mouse movement, keyboard input etc).
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/// This saves CPU.
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Reactive,
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}
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pub struct WebInfo {
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/// e.g. "#fragment" part of "www.example.com/index.html#fragment"
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pub web_location_hash: String,
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}
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pub trait Backend {
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fn run_mode(&self) -> RunMode;
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fn set_run_mode(&mut self, run_mode: RunMode);
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/// If the app is running in a Web context, this returns information about the environment.
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fn web_info(&self) -> Option<WebInfo> {
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None
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}
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/// excludes painting
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fn cpu_time(&self) -> f32;
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/// Smoothed frames per second
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fn fps(&self) -> f32;
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/// Signal the backend that we'd like to exit the app now.
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/// This does nothing for web apps.s
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fn quit(&mut self) {}
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}
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/// A place where you can store custom data in a way that persists when you restart the app.
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///
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/// On the web this is backed by [local storage](https://developer.mozilla.org/en-US/docs/Web/API/Window/localStorage).
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/// On desktop this is backed by the file system.
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pub trait Storage {
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fn get_string(&self, key: &str) -> Option<&str>;
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fn set_string(&mut self, key: &str, value: String);
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}
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#[cfg(feature = "with_serde")]
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pub fn get_value<T: serde::de::DeserializeOwned>(storage: &dyn Storage, key: &str) -> Option<T> {
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storage
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.get_string(key)
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.and_then(|value| serde_json::from_str(value).ok())
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}
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#[cfg(feature = "with_serde")]
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pub fn set_value<T: serde::Serialize>(storage: &mut dyn Storage, key: &str, value: &T) {
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storage.set_string(key, serde_json::to_string(value).unwrap());
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}
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/// storage key used for app
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pub const APP_KEY: &str = "app";
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