[examples] Add layout example

Cargo.toml

@@ -85,3 +85,7 @@ path = "examples/tabs.rs"
 [[example]]
 name = "user_input"
 path = "examples/user_input.rs"
+
+[[example]]
+name = "layout"
+path = "examples/layout.rs"

examples/layout.rs

@@ -0,0 +1,104 @@
+extern crate log;
+extern crate stderrlog;
+extern crate termion;
+extern crate tui;
+
+use std::io;
+use std::thread;
+use std::sync::mpsc;
+
+use termion::event;
+use termion::input::TermRead;
+
+use tui::Terminal;
+use tui::backend::MouseBackend;
+use tui::widgets::{Block, Borders, Widget};
+use tui::layout::{Direction, Group, Rect, Size};
+
+struct App {
+    size: Rect,
+}
+
+impl App {
+    fn new() -> App {
+        App {
+            size: Rect::default(),
+        }
+    }
+}
+
+enum Event {
+    Input(event::Key),
+}
+
+fn main() {
+    stderrlog::new().verbosity(4).init().unwrap();
+
+    // Terminal initialization
+    let backend = MouseBackend::new().unwrap();
+    let mut terminal = Terminal::new(backend).unwrap();
+
+    // Channels
+    let (tx, rx) = mpsc::channel();
+    let input_tx = tx.clone();
+
+    // Input
+    thread::spawn(move || {
+        let stdin = io::stdin();
+        for c in stdin.keys() {
+            let evt = c.unwrap();
+            input_tx.send(Event::Input(evt)).unwrap();
+            if evt == event::Key::Char('q') {
+                break;
+            }
+        }
+    });
+
+    // App
+    let mut app = App::new();
+
+    // First draw call
+    terminal.clear().unwrap();
+    terminal.hide_cursor().unwrap();
+    app.size = terminal.size().unwrap();
+    draw(&mut terminal, &app);
+
+    loop {
+        let size = terminal.size().unwrap();
+        if size != app.size {
+            terminal.resize(size).unwrap();
+            app.size = size;
+        }
+
+        let evt = rx.recv().unwrap();
+        match evt {
+            Event::Input(input) => match input {
+                event::Key::Char('q') => {
+                    break;
+                }
+                _ => {}
+            },
+        }
+        draw(&mut terminal, &app);
+    }
+
+    terminal.show_cursor().unwrap();
+}
+
+fn draw(t: &mut Terminal<MouseBackend>, app: &App) {
+    Group::default()
+        .direction(Direction::Vertical)
+        .sizes(&[Size::Percent(10), Size::Percent(80), Size::Percent(10)])
+        .render(t, &app.size, |t, chunks| {
+            Block::default()
+                .title("Block")
+                .borders(Borders::ALL)
+                .render(t, &chunks[0]);
+            Block::default()
+                .title("Block 2")
+                .borders(Borders::ALL)
+                .render(t, &chunks[2]);
+        });
+
+    t.draw().unwrap();
+}