egui/crates/egui_demo_lib/src/demo/about.rs

94 lines
3.2 KiB
Rust

#[derive(Default)]
#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
#[cfg_attr(feature = "serde", serde(default))]
pub struct About {}
impl super::Demo for About {
fn name(&self) -> &'static str {
"About egui"
}
fn show(&mut self, ctx: &egui::Context, open: &mut bool) {
egui::Window::new(self.name())
.default_width(320.0)
.open(open)
.show(ctx, |ui| {
use super::View as _;
self.ui(ui);
});
}
}
impl super::View for About {
fn ui(&mut self, ui: &mut egui::Ui) {
use egui::special_emojis::{OS_APPLE, OS_LINUX, OS_WINDOWS};
ui.heading("egui");
ui.label(format!(
"egui is an immediate mode GUI library written in Rust. egui runs both on the web and natively on {}{}{}. \
On the web it is compiled to WebAssembly and rendered with WebGL.{}",
OS_APPLE, OS_LINUX, OS_WINDOWS,
if cfg!(target_arch = "wasm32") {
" Everything you see is rendered as textured triangles. There is no DOM, HTML, JS or CSS. Just Rust."
} else {""}
));
ui.label("egui is designed to be easy to use, portable, and fast.");
ui.add_space(12.0); // ui.separator();
ui.heading("Immediate mode");
about_immediate_mode(ui);
ui.add_space(12.0); // ui.separator();
ui.heading("Links");
links(ui);
}
}
fn about_immediate_mode(ui: &mut egui::Ui) {
ui.style_mut().spacing.interact_size.y = 0.0; // hack to make `horizontal_wrapped` work better with text.
ui.horizontal_wrapped(|ui| {
ui.spacing_mut().item_spacing.x = 0.0;
ui.label("Immediate mode is a GUI paradigm that lets you create a GUI with less code and simpler control flow. For example, this is how you create a ");
let _ = ui.small_button("button");
ui.label(" in egui:");
});
ui.add_space(8.0);
crate::rust_view_ui(
ui,
r#"
if ui.button("Save").clicked() {
my_state.save();
}"#
.trim_start_matches('\n'),
);
ui.add_space(8.0);
ui.label("Note how there are no callbacks or messages, and no button state to store.");
ui.label("Immediate mode has its roots in gaming, where everything on the screen is painted at the display refresh rate, i.e. at 60+ frames per second. \
In immediate mode GUIs, the entire interface is laid out and painted at the same high rate. \
This makes immediate mode GUIs especially well suited for highly interactive applications.");
ui.horizontal_wrapped(|ui| {
ui.spacing_mut().item_spacing.x = 0.0;
ui.label("More about immediate mode ");
ui.hyperlink_to("here", "https://github.com/emilk/egui#why-immediate-mode");
ui.label(".");
});
}
fn links(ui: &mut egui::Ui) {
use egui::special_emojis::{GITHUB, TWITTER};
ui.hyperlink_to(
format!("{GITHUB} egui on GitHub"),
"https://github.com/emilk/egui",
);
ui.hyperlink_to(
format!("{TWITTER} @ernerfeldt"),
"https://twitter.com/ernerfeldt",
);
ui.hyperlink_to("egui documentation", "https://docs.rs/egui/");
}