Crate terminput

Expand description

§terminput

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A library to abstract over various backends that provide input events, such as key presses and mouse clicks. This was mainly created as a common interface to the terminal backends that Ratatui supports.

Many TUI libraries want to support input from multiple backends, but mapping each backend’s input structure into a common interface can be tedious. This library aims to provide a uniform interface to these types.

Additionally, we supply methods for parsing and encoding ANSI escape sequences for events.

§Usage

Use the conversion methods provided by the integration crates to convert to and from from terminput’s event types.

use crossterm::event::read;
use std::io;
use terminput::Event;
use terminput_crossterm::{to_crossterm, to_terminput};

fn main() -> io::Result<()> {
    let crossterm_event = read()?;
    let event: Result<Event, _> = to_terminput(crossterm_event);
    println!("{event:?}");

    if let Ok(event) = event {
        // Conversions work both ways
        let event2: Result<crossterm::event::Event, _> = to_crossterm(event);
        println!("{event2:?}");
    }

    Ok(())
}

§Event Matching

Some helpers for matching on events are included. See the match_event example.

§Backends

The following backends are currently supported via separate integration crates:

The Event struct provided by this library is an attempt to create a superset of all supported backend functionality that TUI apps may be interested in.

The following table shows the matrix of supported features:

	crossterm	termion	termwiz	egui
key press	✓	✓	✓	✓
key release/repeat	✓			✓
mouse down	✓	✓	✓	✓
mouse up	✓	✓		✓
mouse move	✓		✓	✓
mouse drag	✓	✓
focus	✓			✓
paste	✓		✓	✓
resize	✓		✓

§Parsing

Use the Event::parse_from method to parse an ANSI-encoded sequence of bytes into an event struct. This can be helpful for usage with SSH or other situations where you need to read raw input from something other than a normal TTY device.

The input parser used here was extracted from crossterm’s implementation.

use terminput::Event;

fn read_input(input: &[u8]) {
    let event = Event::parse_from(input);

    match event {
        Ok(Some(event)) => {
            println!("Successfully parsed input: {event:?}");
        }
        Ok(None) => {
            println!("More input required");
        }
        Err(e) => {
            println!("Unable to parse input: {e:?}");
        }
    }
}

§Encoding

Input structs can also be encoded into ANSI escape sequences using Event::encode. This can be useful if you’re controlling a child pty and need to send it some encoded input.

use terminput::{Encoding, Event, KeyCode, KeyEvent, KittyFlags};

let event = Event::Key(KeyEvent::new(KeyCode::Char('a')));
let mut buf = [0; 16];

// Legacy encoding
let written = event.encode(&mut buf, Encoding::Xterm);
if let Ok(written) = written {
    println!("Encoded: {:?}", &buf[..written]);
}

// Kitty encoding
let mut buf = [0; 16];
let written = event.encode(&mut buf, Encoding::Kitty(KittyFlags::all()));
if let Ok(written) = written {
    println!("Encoded: {:?}", &buf[..written]);
}

§Supported Rust Versions

The MSRV is currently 1.85.0. Since Cargo’s V3 resolver supports MSRV-aware dependencies, we do not treat an MSRV bump as a breaking change.

Macros§

key: Pattern matching for key events.
modifiers: Macro for combining key modifiers in a way that’s valid in const contexts. Useful for match expressions.
states: Macro for combining key states together in a way that’s valid in const contexts. Useful for match expressions.

Structs§

KeyEvent: A key input event.
KeyEventState: Represents extra state about the key event.
KeyModifiers: Represents key modifiers (shift, control, alt, etc.).
KittyFlags: Controls which keyboard enhancement flags will be considered during encoding. These flags are described in Kitty’s documentation on progressive enhancement.
MouseEvent: A mouse event.
ScrollDelta: Represents the change that should be applied to the content in response to a scroll event.
UnsupportedEvent: The supplied event could not be converted into the requested type.

Enums§

Encoding: Encoding protocol used to control the output of Event::encode
Event: An application event.
KeyCode: Represents a key.
KeyEventKind: Type of key event. Repeat and release events may not be emitted if the input source is not configured to do so.
MediaKeyCode: Media keys.
ModifierDirection: Represents whether the modifier came from the left or right side of the keyboard, where applicable.
ModifierKeyCode: A modifier key event.
MouseButton: The mouse button used for this event.
MouseEventKind: The type of mouse event.
Repeats: Whether to include KeyEventKind::Repeat when checking for key down events.
ScrollDirection: Mouse scroll direction.

Constants§

ALT: Alt modifier.
CAPS_LOCK: Caps lock event state.
CTRL: Ctrl modifier.
HYPER: Hyper modifier.
KEYPAD: Keypad event state.
META: Meta modifier.
NUM_LOCK: Num lock event state.
SHIFT: Shift modifier.
SUPER: Super modifier.

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