rdev 0.4.0

Simple library to listen and send events to keyboard and mouse.

You can also check out Enigo which is another crate which helped me write this one.

This crate is so far a pet project for me to understand the rust ecosystem.

Simple Usage

Listening to global events

use rdev::{listen, Event};

fn main() {
    // This will block.
    if let Err(error) = listen(callback) {
        println!("Error: {:?}", error)
    }
}

fn callback(event: Event) {
    println!("My callback {:?}", event);
    match event.name {
        Some(string) => println!("User wrote {:?}", string),
        None => (),
    }
}

Sending some events

use rdev::{simulate, Button, EventType, Key, SimulateError};
use std::{thread, time};

fn send(event_type: &EventType) {
    let delay = time::Duration::from_millis(20);
    match simulate(event_type) {
        Ok(()) => (),
        Err(SimulateError) => {
            println!("We could not send {:?}", event_type);
        }
    }
    // Let ths OS catchup (at least MacOS)
    thread::sleep(delay);
}

fn main() {
    send(&EventType::KeyPress(Key::KeyS));
    send(&EventType::KeyRelease(Key::KeyS));

    send(&EventType::MouseMove { x: 0.0, y: 0.0 });
    send(&EventType::MouseMove { x: 400.0, y: 400.0 });
    send(&EventType::ButtonPress(Button::Left));
    send(&EventType::ButtonRelease(Button::Right));
    send(&EventType::Wheel {
        delta_x: 0,
        delta_y: 1,
    });
}

Getting the main screen size

use rdev::{display_size};

fn main() {
    let (w, h) = display_size();
    assert!(w > 0);
    assert!(h > 0);
}

Keyboard state

We can define a dummy Keyboard, that we will use to detect what kind of EventType trigger some String. We get the currently used layout for now ! Caveat : This is layout dependent. If your app needs to support layout switching don't use this ! Caveat: On Linux, the dead keys mechanism is not implemented. Caveat: Only shift and dead keys are implemented, Alt+unicode code on windows won't work.

use rdev::{Keyboard, EventType, Key, KeyboardState};

let mut keyboard = Keyboard::new().unwrap();
let string = keyboard.add(&EventType::KeyPress(Key::KeyS));
// string == Some("s")

Grabbing global events.

In the callback, returning None ignores the event and returning the event let's it pass. There is no modification of the event possible here. Caveat: On MacOS, you require the grab loop needs to be the primary app (no fork before) and need to have accessibility settings enabled. On Linux, this is not implemented, you will always receive an error.

use rdev::{grab, Event, EventType, Key};

fn callback(event: Event) -> Option<Event> {
    println!("My callback {:?}", event);
    match event.event_type{
        EventType::KeyPress(Key::Tab) => None,
        _ => Some(event),
    }
}
fn main(){
    // This will block.
    if let Err(error) = grab(callback) {
        println!("Error: {:?}", error)
    }
}

Serialization

Serialization and deserialization is optional behind the feature "serialize".

Event struct

In order to detect what a user types, we need to plug to the OS level management of keyboard state (modifiers like shift, ctrl, but also dead keys if they exist).

In order to see what is the outcome of an event, you need to read the Event::name option.

/// When events arrive from the system we can add some information
/// time is when the event was received, name *will* be at some point changed
/// to be mapped to the function of the key (Alt, s, Return and so on).
#[derive(Debug)]
pub struct Event {
    pub time: SystemTime,
    pub name: Option<String>,
    pub event_type: EventType,
}

Be careful, Event::name, might be None, but also String::from(""), and might contain not displayable unicode characters. We send exactly what the OS sends us so do some sanity checking before using it. Caveat: Dead keys don't function yet on Linux

Events enum

In order to manage different OS, the current EventType choices is a mix&match to account for all possible events. There is a safe mechanism to detect events no matter what, which are the Unknown() variant of the enum which will contain some OS specific value. Also not that not all keys are mapped to an OS code, so simulate might fail if you try to send an unmapped key. Sending Unknown() variants will always work (the OS might still reject it).

/// In order to manage different OS, the current EventType choices is a mix&match
/// to account for all possible events.
#[derive(Debug)]
pub enum EventType {
    /// The keys correspond to a standard qwerty layout, they don't correspond
    /// To the actual letter a user would use, that requires some layout logic to be added.
    KeyPress(Key),
    KeyRelease(Key),
    /// Some mouse will have more than 3 buttons, these are not defined, and different OS will
    /// give different Unknown code.
    ButtonPress(Button),
    ButtonRelease(Button),
    /// Values in pixels
    MouseMove {
        x: f64,
        y: f64,
    },
    /// Note: On Linux, there is no actual delta the actual values are ignored for delta_x
    /// and we only look at the sign of delta_y to simulate wheelup or wheeldown.
    Wheel {
        delta_x: i64,
        delta_y: i64,
    },
}

OS Specificities

For now the code only works for Linux (X11), MacOS and Windows. On MacOS, the listen loop needs to be the primary app (no fork before) and needs to have accessibility settings enabled (Terminal added in System Preferences > Security & Privacy > Privacy > Accessibility).