keycode

A Rust crate for translating keycodes based on Chrome's mapping of keys.

Easily convert, generate, listen for, or map keycodes for Linux, Windows, Mac, USB, and browsers! Includes a struct to manage the state of pressed keys and generate USB HID reports. Can be used for #![no_std] crates.

Source Data

Source of keycodes data:

• Repo: https://chromium.googlesource.com/chromium/src.git
• File: https://chromium.googlesource.com/chromium/src.git/+/master/ui/events/keycodes/dom/keycode_converter_data.inc
• Git commit: 2b6022954b9fb600f15e08002a148187f4f986da

How to update source file:

curl -sL 'https://chromium.googlesource.com/chromium/src/+/master/ui/events/keycodes/dom/keycode_converter_data.inc?format=TEXT' | base64 --decode > keycode_converter_data.inc

Examples

Get a key mapping

use keycode::{KeyMap, KeyMappingId};

// Check the USB HID value of the "a" key
fn main() {
    let a = KeyMap::from(KeyMappingId::UsA);
    assert_eq!(a.usb, 0x0004);
    assert_eq!(a.evdev, 0x001e);
    assert_eq!(a.xkb, 0x0026);
    assert_eq!(a.win, 0x001e);
    assert_eq!(a.mac, 0x0000);
}

Generate a USB HID report

use keycode::{KeyboardState, KeyMap, KeyMappingId, KeyState};

// Press and release the "A" key
fn main() {
    // Generate a keyboard state with n-key rollover
    let mut keyboard_state = KeyboardState::new(None);

    // Get key mappings
    let a = KeyMap::from(KeyMappingId::UsA);
    let shift = KeyMap::from(KeyMappingId::ShiftLeft);

    // USB HID report for "no keys pressed"
    assert_eq!(keyboard_state.usb_input_report(), &[0; 8]);

    // Press "shift" and "a" keys
    keyboard_state.update_key(a, KeyState::Pressed);
    keyboard_state.update_key(shift, KeyState::Pressed);

    // USB HID report for "'A' is pressed"
    assert_eq!(
        keyboard_state.usb_input_report(),
        &[shift.modifier.unwrap().bits(), 0, a.usb as u8, 0, 0, 0, 0, 0]
    );

    // Release "shift" and "a" keys
    keyboard_state.update_key(a, KeyState::Released);
    keyboard_state.update_key(shift, KeyState::Released);

    // USB HID report for "no keys pressed"
    assert_eq!(keyboard_state.usb_input_report(), &[0; 8]);
}

Supported Rust Versions

Requires Rust 1.34.0 or newer due to use of TryFrom.

Developing

I recommend to use Nix and the flake within this repo:

nix develop