//! Demonstrates how to block read events. | |
//! | |
//! cargo run --example event-read | |
use std::io::stdout; | |
use crossterm::event::poll; | |
use crossterm::{ | |
cursor::position, | |
event::{read, DisableMouseCapture, EnableMouseCapture, Event, KeyCode}, | |
execute, | |
terminal::{disable_raw_mode, enable_raw_mode}, | |
Result, | |
}; | |
use std::time::Duration; | |
const HELP: &str = r#"Blocking read() | |
- Keyboard, mouse and terminal resize events enabled | |
- Hit "c" to print current cursor position | |
- Use Esc to quit | |
"#; | |
fn print_events() -> Result<()> { | |
loop { | |
// Blocking read | |
let event = read()?; | |
println!("Event: {:?}\r", event); | |
if event == Event::Key(KeyCode::Char('c').into()) { | |
println!("Cursor position: {:?}\r", position()); | |
} | |
if let Event::Resize(_, _) = event { | |
let (original_size, new_size) = flush_resize_events(event); | |
println!("Resize from: {:?}, to: {:?}", original_size, new_size); | |
} | |
if event == Event::Key(KeyCode::Esc.into()) { | |
break; | |
} | |
} | |
Ok(()) | |
} | |
// Resize events can occur in batches. | |
// With a simple loop they can be flushed. | |
// This function will keep the first and last resize event. | |
fn flush_resize_events(event: Event) -> ((u16, u16), (u16, u16)) { | |
if let Event::Resize(x, y) = event { | |
let mut last_resize = (x, y); | |
loop { | |
if let Ok(true) = poll(Duration::from_millis(50)) { | |
if let Ok(Event::Resize(x, y)) = read() { | |
last_resize = (x, y); | |
} | |
} else { | |
break; | |
} | |
} | |
return ((x, y), last_resize); | |
} | |
((0, 0), (0, 0)) | |
} | |
fn main() -> Result<()> { | |
println!("{}", HELP); | |
enable_raw_mode()?; | |
let mut stdout = stdout(); | |
execute!(stdout, EnableMouseCapture)?; | |
if let Err(e) = print_events() { | |
println!("Error: {:?}\r", e); | |
} | |
execute!(stdout, DisableMouseCapture)?; | |
disable_raw_mode() | |
} |