use std::fmt::Write;
pub trait Widget {
/// Natural width of `self`.
fn width(&self) -> usize;
/// Draw the widget into a buffer.
fn draw_into(&self, buffer: &mut dyn std::fmt::Write);
/// Draw the widget on standard output.
fn draw(&self) {
let mut buffer = String::new();
self.draw_into(&mut buffer);
println!("{}", &buffer);
}
}
pub struct Label {
label: String,
}
impl Label {
fn new(label: &str) -> Label {
Label {
label: label.to_owned(),
}
}
}
pub struct Button {
label: Label,
callback: Box<dyn FnMut()>,
}
impl Button {
fn new(label: &str, callback: Box<dyn FnMut()>) -> Button {
Button {
label: Label::new(label),
callback,
}
}
}
pub struct Window {
title: String,
widgets: Vec<Box<dyn Widget>>,
}
impl Window {
fn new(title: &str) -> Window {
Window {
title: title.to_owned(),
widgets: Vec::new(),
}
}
fn add_widget(&mut self, widget: Box<dyn Widget>) {
self.widgets.push(widget);
}
}
impl Widget for Label {
fn width(&self) -> usize {
unimplemented!()
}
fn draw_into(&self, buffer: &mut dyn std::fmt::Write) {
buffer.write_str(self.label.as_str()).unwrap();
}
}
impl Widget for Button {
fn width(&self) -> usize {
unimplemented!()
}
fn draw_into(&self, buffer: &mut dyn std::fmt::Write) {
buffer.write_str("\n|").unwrap();
buffer.write_str(&self.label.label.as_str()).unwrap();
buffer.write_str("|\n").unwrap();
}
}
impl Widget for Window {
fn width(&self) -> usize {
10
}
fn draw_into(&self, buffer: &mut dyn std::fmt::Write) {
buffer.write_str("\n--------------\n").unwrap();
buffer.write_str(self.title.as_str()).unwrap();
buffer.write_str("\n--------------\n").unwrap();
for w in &self.widgets {
w.draw_into(buffer)
}
}
}
fn main() {
let mut window = Window::new("Rust GUI Demo 1.23");
window.add_widget(Box::new(Label::new("This is a small text GUI demo.")));
window.add_widget(Box::new(Button::new(
"Click me!",
Box::new(|| println!("You clicked the button!")),
)));
window.draw();