rust-sdl2/examples/mouse-state.rs

extern crate sdl2;

use sdl2::event::Event;
use sdl2::keyboard::Keycode;
use std::collections::HashSet;
use std::time::Duration;

pub fn main() -> Result<(), String> {
    let sdl_context = sdl2::init()?;
    let video_subsystem = sdl_context.video()?;

    let _window = video_subsystem
        .window("Mouse", 800, 600)
        .position_centered()
        .build()
        .map_err(|e| e.to_string())?;

    let mut events = sdl_context.event_pump()?;

    let mut prev_buttons = HashSet::new();

    'running: loop {
        for event in events.poll_iter() {
            match event {
                Event::KeyDown {
                    keycode: Some(Keycode::Escape),
                    ..
                }
                | Event::Quit { .. } => break 'running,
                _ => {}
            }
        }

        // get a mouse state
        let state = events.mouse_state();

        // Create a set of pressed Keys.
        let buttons = state.pressed_mouse_buttons().collect();

        // Get the difference between the new and old sets.
        let new_buttons = &buttons - &prev_buttons;
        let old_buttons = &prev_buttons - &buttons;

        if !new_buttons.is_empty() || !old_buttons.is_empty() {
            println!(
                "X = {:?}, Y = {:?} : {:?} -> {:?}",
                state.x(),
                state.y(),
                new_buttons,
                old_buttons
            );
        }

        prev_buttons = buttons;

        std::thread::sleep(Duration::from_millis(100));
    }

    Ok(())
}