Support non-US keyboard layout on macOS

This commit implements a look up table to map between CGKeyCode
on the physical keyboard and the actual output character from the
selected input source. This table is built once when the application
starts.

Currently, we have to restart the application if we change the
input source. This can be improved in the future.

Fixes #20

Cargo.toml

@@ -17,6 +17,7 @@ vi = "0.3.5"
 bitflags = "1.3.2"
 druid = "0.7.0"
 once_cell = "1.17.0"
+rdev = "0.5.2"
 
 [package.metadata.bundle]
 copyright = "Copyright (c) Huy Tran 2023. All rights reserved."

src/input.rs

@@ -1,8 +1,8 @@
-use std::{fmt::Display, str::FromStr};
+use std::{collections::HashMap, fmt::Display, str::FromStr};
 
 use druid::{Data, Target};
 use log::debug;
-use once_cell::sync::Lazy;
+use once_cell::sync::{Lazy, OnceCell};
 
 use crate::{
     config::{CONFIG_MANAGER, HOTKEY_CONFIG_KEY, TYPING_METHOD_CONFIG_KEY},
@@ -32,6 +32,68 @@ const TONABLE_VOWELS: [char; 144] = [
 
 pub static mut INPUT_STATE: Lazy<InputState> = Lazy::new(|| InputState::new());
 
+pub const PREDEFINED_CHARS: [char; 47] = [
+    'a', '`', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '-', '=', 'q', 'w', 'e', 'r', 't',
+    'y', 'u', 'i', 'o', 'p', '[', ']', 's', 'd', 'f', 'g', 'h', 'j', 'k', 'l', ';', '\'', '\\',
+    'z', 'x', 'c', 'v', 'b', 'n', 'm', ',', '.', '/',
+];
+
+pub fn get_key_from_char(c: char) -> rdev::Key {
+    use rdev::Key::*;
+    match &c {
+        'a' => KeyA,
+        '`' => BackQuote,
+        '1' => Num1,
+        '2' => Num2,
+        '3' => Num3,
+        '4' => Num4,
+        '5' => Num5,
+        '6' => Num6,
+        '7' => Num7,
+        '8' => Num8,
+        '9' => Num9,
+        '0' => Num0,
+        '-' => Minus,
+        '=' => Equal,
+        'q' => KeyQ,
+        'w' => KeyW,
+        'e' => KeyE,
+        'r' => KeyR,
+        't' => KeyT,
+        'y' => KeyY,
+        'u' => KeyU,
+        'i' => KeyI,
+        'o' => KeyO,
+        'p' => KeyP,
+        '[' => LeftBracket,
+        ']' => RightBracket,
+        's' => KeyS,
+        'd' => KeyD,
+        'f' => KeyF,
+        'g' => KeyG,
+        'h' => KeyH,
+        'j' => KeyJ,
+        'k' => KeyK,
+        'l' => KeyL,
+        ';' => SemiColon,
+        '\'' => Quote,
+        '\\' => BackSlash,
+        'z' => KeyZ,
+        'x' => KeyX,
+        'c' => KeyC,
+        'v' => KeyV,
+        'b' => KeyB,
+        'n' => KeyN,
+        'm' => KeyM,
+        ',' => Comma,
+        '.' => Dot,
+        '/' => Slash,
+        _ => Unknown(0),
+    }
+}
+
+pub static KEYBOARD_LAYOUT_CHARACTER_MAP: OnceCell<HashMap<char, char>> = OnceCell::new();
+
 #[derive(PartialEq, Eq, Data, Clone, Copy)]
 pub enum TypingMethod {
     VNI,

src/main.rs

@@ -5,14 +5,15 @@ mod platform;
 mod ui;
 
 use druid::{AppLauncher, ExtEventSink, Target, WindowDesc};
-use input::INPUT_STATE;
+use input::{get_key_from_char, INPUT_STATE, KEYBOARD_LAYOUT_CHARACTER_MAP, PREDEFINED_CHARS};
 use log::debug;
 use once_cell::sync::OnceCell;
 use platform::{
     run_event_listener, send_backspace, send_string, Handle, KeyModifier, KEY_DELETE, KEY_ENTER,
     KEY_ESCAPE, KEY_SPACE, KEY_TAB,
 };
-use std::thread;
+use rdev::{EventType, Keyboard, KeyboardState};
+use std::{collections::HashMap, thread};
 use ui::{UIDataAdapter, UPDATE_UI};
 
 static UI_EVENT_SINK: OnceCell<ExtEventSink> = OnceCell::new();
@@ -38,6 +39,7 @@ fn event_handler(handle: Handle, keycode: Option<char>, modifiers: KeyModifier)
     unsafe {
         match keycode {
             Some(keycode) => {
+                println!("KEYCODE: {}", keycode);
                 // Toggle Vietnamese input mod with Ctrl + Cmd + Space key
                 if INPUT_STATE.get_hotkey().is_match(modifiers, &keycode) {
                     INPUT_STATE.toggle_vietnamese();
@@ -99,6 +101,17 @@ fn event_handler(handle: Handle, keycode: Option<char>, modifiers: KeyModifier)
 fn main() {
     env_logger::init();
 
+    let mut map = HashMap::new();
+    let mut kb = Keyboard::new().unwrap();
+    for c in PREDEFINED_CHARS {
+        let key = rdev::EventType::KeyPress(get_key_from_char(c));
+        if let Some(s) = kb.add(&key) {
+            let ch = s.chars().last().unwrap();
+            map.insert(c, ch);
+        }
+    }
+    _ = KEYBOARD_LAYOUT_CHARACTER_MAP.set(map);
+
     let win = WindowDesc::new(ui::main_ui_builder)
         .title("gõkey")
         .window_size((320.0, 234.0))