events.rs

   1use std::rc::Rc;
   2
   3use ::util::ResultExt;
   4use anyhow::Context as _;
   5use windows::{
   6    Win32::{
   7        Foundation::*,
   8        Graphics::Gdi::*,
   9        System::SystemServices::*,
  10        UI::{
  11            Controls::*,
  12            HiDpi::*,
  13            Input::{Ime::*, KeyboardAndMouse::*},
  14            WindowsAndMessaging::*,
  15        },
  16    },
  17    core::PCWSTR,
  18};
  19
  20use crate::*;
  21
  22pub(crate) const WM_GPUI_CURSOR_STYLE_CHANGED: u32 = WM_USER + 1;
  23pub(crate) const WM_GPUI_CLOSE_ONE_WINDOW: u32 = WM_USER + 2;
  24pub(crate) const WM_GPUI_TASK_DISPATCHED_ON_MAIN_THREAD: u32 = WM_USER + 3;
  25pub(crate) const WM_GPUI_DOCK_MENU_ACTION: u32 = WM_USER + 4;
  26
  27const SIZE_MOVE_LOOP_TIMER_ID: usize = 1;
  28const AUTO_HIDE_TASKBAR_THICKNESS_PX: i32 = 1;
  29
  30pub(crate) fn handle_msg(
  31    handle: HWND,
  32    msg: u32,
  33    wparam: WPARAM,
  34    lparam: LPARAM,
  35    state_ptr: Rc<WindowsWindowStatePtr>,
  36) -> LRESULT {
  37    let handled = match msg {
  38        WM_ACTIVATE => handle_activate_msg(handle, wparam, state_ptr),
  39        WM_CREATE => handle_create_msg(handle, state_ptr),
  40        WM_MOVE => handle_move_msg(handle, lparam, state_ptr),
  41        WM_SIZE => handle_size_msg(wparam, lparam, state_ptr),
  42        WM_GETMINMAXINFO => handle_get_min_max_info_msg(lparam, state_ptr),
  43        WM_ENTERSIZEMOVE | WM_ENTERMENULOOP => handle_size_move_loop(handle),
  44        WM_EXITSIZEMOVE | WM_EXITMENULOOP => handle_size_move_loop_exit(handle),
  45        WM_TIMER => handle_timer_msg(handle, wparam, state_ptr),
  46        WM_NCCALCSIZE => handle_calc_client_size(handle, wparam, lparam, state_ptr),
  47        WM_DPICHANGED => handle_dpi_changed_msg(handle, wparam, lparam, state_ptr),
  48        WM_DISPLAYCHANGE => handle_display_change_msg(handle, state_ptr),
  49        WM_NCHITTEST => handle_hit_test_msg(handle, msg, wparam, lparam, state_ptr),
  50        WM_PAINT => handle_paint_msg(handle, state_ptr),
  51        WM_CLOSE => handle_close_msg(state_ptr),
  52        WM_DESTROY => handle_destroy_msg(handle, state_ptr),
  53        WM_MOUSEMOVE => handle_mouse_move_msg(handle, lparam, wparam, state_ptr),
  54        WM_MOUSELEAVE | WM_NCMOUSELEAVE => handle_mouse_leave_msg(state_ptr),
  55        WM_NCMOUSEMOVE => handle_nc_mouse_move_msg(handle, lparam, state_ptr),
  56        WM_NCLBUTTONDOWN => {
  57            handle_nc_mouse_down_msg(handle, MouseButton::Left, wparam, lparam, state_ptr)
  58        }
  59        WM_NCRBUTTONDOWN => {
  60            handle_nc_mouse_down_msg(handle, MouseButton::Right, wparam, lparam, state_ptr)
  61        }
  62        WM_NCMBUTTONDOWN => {
  63            handle_nc_mouse_down_msg(handle, MouseButton::Middle, wparam, lparam, state_ptr)
  64        }
  65        WM_NCLBUTTONUP => {
  66            handle_nc_mouse_up_msg(handle, MouseButton::Left, wparam, lparam, state_ptr)
  67        }
  68        WM_NCRBUTTONUP => {
  69            handle_nc_mouse_up_msg(handle, MouseButton::Right, wparam, lparam, state_ptr)
  70        }
  71        WM_NCMBUTTONUP => {
  72            handle_nc_mouse_up_msg(handle, MouseButton::Middle, wparam, lparam, state_ptr)
  73        }
  74        WM_LBUTTONDOWN => handle_mouse_down_msg(handle, MouseButton::Left, lparam, state_ptr),
  75        WM_RBUTTONDOWN => handle_mouse_down_msg(handle, MouseButton::Right, lparam, state_ptr),
  76        WM_MBUTTONDOWN => handle_mouse_down_msg(handle, MouseButton::Middle, lparam, state_ptr),
  77        WM_XBUTTONDOWN => {
  78            handle_xbutton_msg(handle, wparam, lparam, handle_mouse_down_msg, state_ptr)
  79        }
  80        WM_LBUTTONUP => handle_mouse_up_msg(handle, MouseButton::Left, lparam, state_ptr),
  81        WM_RBUTTONUP => handle_mouse_up_msg(handle, MouseButton::Right, lparam, state_ptr),
  82        WM_MBUTTONUP => handle_mouse_up_msg(handle, MouseButton::Middle, lparam, state_ptr),
  83        WM_XBUTTONUP => handle_xbutton_msg(handle, wparam, lparam, handle_mouse_up_msg, state_ptr),
  84        WM_MOUSEWHEEL => handle_mouse_wheel_msg(handle, wparam, lparam, state_ptr),
  85        WM_MOUSEHWHEEL => handle_mouse_horizontal_wheel_msg(handle, wparam, lparam, state_ptr),
  86        WM_SYSKEYDOWN => handle_syskeydown_msg(wparam, lparam, state_ptr),
  87        WM_SYSKEYUP => handle_syskeyup_msg(wparam, lparam, state_ptr),
  88        WM_SYSCOMMAND => handle_system_command(wparam, state_ptr),
  89        WM_KEYDOWN => handle_keydown_msg(wparam, lparam, state_ptr),
  90        WM_KEYUP => handle_keyup_msg(wparam, lparam, state_ptr),
  91        WM_CHAR => handle_char_msg(wparam, state_ptr),
  92        WM_DEADCHAR => handle_dead_char_msg(wparam, state_ptr),
  93        WM_IME_STARTCOMPOSITION => handle_ime_position(handle, state_ptr),
  94        WM_IME_COMPOSITION => handle_ime_composition(handle, lparam, state_ptr),
  95        WM_SETCURSOR => handle_set_cursor(lparam, state_ptr),
  96        WM_SETTINGCHANGE => handle_system_settings_changed(handle, lparam, state_ptr),
  97        WM_INPUTLANGCHANGE => handle_input_language_changed(lparam, state_ptr),
  98        WM_GPUI_CURSOR_STYLE_CHANGED => handle_cursor_changed(lparam, state_ptr),
  99        _ => None,
 100    };
 101    if let Some(n) = handled {
 102        LRESULT(n)
 103    } else {
 104        unsafe { DefWindowProcW(handle, msg, wparam, lparam) }
 105    }
 106}
 107
 108fn handle_move_msg(
 109    handle: HWND,
 110    lparam: LPARAM,
 111    state_ptr: Rc<WindowsWindowStatePtr>,
 112) -> Option<isize> {
 113    let mut lock = state_ptr.state.borrow_mut();
 114    let origin = logical_point(
 115        lparam.signed_loword() as f32,
 116        lparam.signed_hiword() as f32,
 117        lock.scale_factor,
 118    );
 119    lock.origin = origin;
 120    let size = lock.logical_size;
 121    let center_x = origin.x.0 + size.width.0 / 2.;
 122    let center_y = origin.y.0 + size.height.0 / 2.;
 123    let monitor_bounds = lock.display.bounds();
 124    if center_x < monitor_bounds.left().0
 125        || center_x > monitor_bounds.right().0
 126        || center_y < monitor_bounds.top().0
 127        || center_y > monitor_bounds.bottom().0
 128    {
 129        // center of the window may have moved to another monitor
 130        let monitor = unsafe { MonitorFromWindow(handle, MONITOR_DEFAULTTONULL) };
 131        // minimize the window can trigger this event too, in this case,
 132        // monitor is invalid, we do nothing.
 133        if !monitor.is_invalid() && lock.display.handle != monitor {
 134            // we will get the same monitor if we only have one
 135            lock.display = WindowsDisplay::new_with_handle(monitor);
 136        }
 137    }
 138    if let Some(mut callback) = lock.callbacks.moved.take() {
 139        drop(lock);
 140        callback();
 141        state_ptr.state.borrow_mut().callbacks.moved = Some(callback);
 142    }
 143    Some(0)
 144}
 145
 146fn handle_get_min_max_info_msg(
 147    lparam: LPARAM,
 148    state_ptr: Rc<WindowsWindowStatePtr>,
 149) -> Option<isize> {
 150    let lock = state_ptr.state.borrow();
 151    if let Some(min_size) = lock.min_size {
 152        let scale_factor = lock.scale_factor;
 153        let boarder_offset = lock.border_offset;
 154        drop(lock);
 155
 156        unsafe {
 157            let minmax_info = &mut *(lparam.0 as *mut MINMAXINFO);
 158            minmax_info.ptMinTrackSize.x =
 159                min_size.width.scale(scale_factor).0 as i32 + boarder_offset.width_offset;
 160            minmax_info.ptMinTrackSize.y =
 161                min_size.height.scale(scale_factor).0 as i32 + boarder_offset.height_offset;
 162        }
 163        Some(0)
 164    } else {
 165        None
 166    }
 167}
 168
 169fn handle_size_msg(
 170    wparam: WPARAM,
 171    lparam: LPARAM,
 172    state_ptr: Rc<WindowsWindowStatePtr>,
 173) -> Option<isize> {
 174    let mut lock = state_ptr.state.borrow_mut();
 175
 176    // Don't resize the renderer when the window is minimized, but record that it was minimized so
 177    // that on restore the swap chain can be recreated via `update_drawable_size_even_if_unchanged`.
 178    if wparam.0 == SIZE_MINIMIZED as usize {
 179        lock.restore_from_minimized = lock.callbacks.request_frame.take();
 180        return Some(0);
 181    }
 182
 183    let width = lparam.loword().max(1) as i32;
 184    let height = lparam.hiword().max(1) as i32;
 185    let new_size = size(DevicePixels(width), DevicePixels(height));
 186    let scale_factor = lock.scale_factor;
 187    if lock.restore_from_minimized.is_some() {
 188        lock.renderer
 189            .update_drawable_size_even_if_unchanged(new_size);
 190        lock.callbacks.request_frame = lock.restore_from_minimized.take();
 191    } else {
 192        lock.renderer.update_drawable_size(new_size);
 193    }
 194    let new_size = new_size.to_pixels(scale_factor);
 195    lock.logical_size = new_size;
 196    if let Some(mut callback) = lock.callbacks.resize.take() {
 197        drop(lock);
 198        callback(new_size, scale_factor);
 199        state_ptr.state.borrow_mut().callbacks.resize = Some(callback);
 200    }
 201    Some(0)
 202}
 203
 204fn handle_size_move_loop(handle: HWND) -> Option<isize> {
 205    unsafe {
 206        let ret = SetTimer(
 207            Some(handle),
 208            SIZE_MOVE_LOOP_TIMER_ID,
 209            USER_TIMER_MINIMUM,
 210            None,
 211        );
 212        if ret == 0 {
 213            log::error!(
 214                "unable to create timer: {}",
 215                std::io::Error::last_os_error()
 216            );
 217        }
 218    }
 219    None
 220}
 221
 222fn handle_size_move_loop_exit(handle: HWND) -> Option<isize> {
 223    unsafe {
 224        KillTimer(Some(handle), SIZE_MOVE_LOOP_TIMER_ID).log_err();
 225    }
 226    None
 227}
 228
 229fn handle_timer_msg(
 230    handle: HWND,
 231    wparam: WPARAM,
 232    state_ptr: Rc<WindowsWindowStatePtr>,
 233) -> Option<isize> {
 234    if wparam.0 == SIZE_MOVE_LOOP_TIMER_ID {
 235        for runnable in state_ptr.main_receiver.drain() {
 236            runnable.run();
 237        }
 238        handle_paint_msg(handle, state_ptr)
 239    } else {
 240        None
 241    }
 242}
 243
 244fn handle_paint_msg(handle: HWND, state_ptr: Rc<WindowsWindowStatePtr>) -> Option<isize> {
 245    let mut lock = state_ptr.state.borrow_mut();
 246    if let Some(mut request_frame) = lock.callbacks.request_frame.take() {
 247        drop(lock);
 248        request_frame(Default::default());
 249        state_ptr.state.borrow_mut().callbacks.request_frame = Some(request_frame);
 250    }
 251    unsafe { ValidateRect(Some(handle), None).ok().log_err() };
 252    Some(0)
 253}
 254
 255fn handle_close_msg(state_ptr: Rc<WindowsWindowStatePtr>) -> Option<isize> {
 256    let mut lock = state_ptr.state.borrow_mut();
 257    if let Some(mut callback) = lock.callbacks.should_close.take() {
 258        drop(lock);
 259        let should_close = callback();
 260        state_ptr.state.borrow_mut().callbacks.should_close = Some(callback);
 261        if should_close { None } else { Some(0) }
 262    } else {
 263        None
 264    }
 265}
 266
 267fn handle_destroy_msg(handle: HWND, state_ptr: Rc<WindowsWindowStatePtr>) -> Option<isize> {
 268    let callback = {
 269        let mut lock = state_ptr.state.borrow_mut();
 270        lock.callbacks.close.take()
 271    };
 272    if let Some(callback) = callback {
 273        callback();
 274    }
 275    unsafe {
 276        PostThreadMessageW(
 277            state_ptr.main_thread_id_win32,
 278            WM_GPUI_CLOSE_ONE_WINDOW,
 279            WPARAM(state_ptr.validation_number),
 280            LPARAM(handle.0 as isize),
 281        )
 282        .log_err();
 283    }
 284    Some(0)
 285}
 286
 287fn handle_mouse_move_msg(
 288    handle: HWND,
 289    lparam: LPARAM,
 290    wparam: WPARAM,
 291    state_ptr: Rc<WindowsWindowStatePtr>,
 292) -> Option<isize> {
 293    start_tracking_mouse(handle, &state_ptr, TME_LEAVE);
 294
 295    let mut lock = state_ptr.state.borrow_mut();
 296    let Some(mut func) = lock.callbacks.input.take() else {
 297        return Some(1);
 298    };
 299    let scale_factor = lock.scale_factor;
 300    drop(lock);
 301
 302    let pressed_button = match MODIFIERKEYS_FLAGS(wparam.loword() as u32) {
 303        flags if flags.contains(MK_LBUTTON) => Some(MouseButton::Left),
 304        flags if flags.contains(MK_RBUTTON) => Some(MouseButton::Right),
 305        flags if flags.contains(MK_MBUTTON) => Some(MouseButton::Middle),
 306        flags if flags.contains(MK_XBUTTON1) => {
 307            Some(MouseButton::Navigate(NavigationDirection::Back))
 308        }
 309        flags if flags.contains(MK_XBUTTON2) => {
 310            Some(MouseButton::Navigate(NavigationDirection::Forward))
 311        }
 312        _ => None,
 313    };
 314    let x = lparam.signed_loword() as f32;
 315    let y = lparam.signed_hiword() as f32;
 316    let input = PlatformInput::MouseMove(MouseMoveEvent {
 317        position: logical_point(x, y, scale_factor),
 318        pressed_button,
 319        modifiers: current_modifiers(),
 320    });
 321    let handled = !func(input).propagate;
 322    state_ptr.state.borrow_mut().callbacks.input = Some(func);
 323
 324    if handled { Some(0) } else { Some(1) }
 325}
 326
 327fn handle_mouse_leave_msg(state_ptr: Rc<WindowsWindowStatePtr>) -> Option<isize> {
 328    let mut lock = state_ptr.state.borrow_mut();
 329    lock.hovered = false;
 330    if let Some(mut callback) = lock.callbacks.hovered_status_change.take() {
 331        drop(lock);
 332        callback(false);
 333        state_ptr.state.borrow_mut().callbacks.hovered_status_change = Some(callback);
 334    }
 335
 336    Some(0)
 337}
 338
 339fn handle_syskeydown_msg(
 340    wparam: WPARAM,
 341    lparam: LPARAM,
 342    state_ptr: Rc<WindowsWindowStatePtr>,
 343) -> Option<isize> {
 344    let mut lock = state_ptr.state.borrow_mut();
 345    let input = handle_key_event(wparam, lparam, &mut lock, |keystroke| {
 346        PlatformInput::KeyDown(KeyDownEvent {
 347            keystroke,
 348            is_held: lparam.0 & (0x1 << 30) > 0,
 349        })
 350    })?;
 351    let mut func = lock.callbacks.input.take()?;
 352    drop(lock);
 353
 354    let handled = !func(input).propagate;
 355
 356    let mut lock = state_ptr.state.borrow_mut();
 357    lock.callbacks.input = Some(func);
 358
 359    if handled {
 360        lock.system_key_handled = true;
 361        lock.suppress_next_char_msg = true;
 362        Some(0)
 363    } else {
 364        // we need to call `DefWindowProcW`, or we will lose the system-wide `Alt+F4`, `Alt+{other keys}`
 365        // shortcuts.
 366        None
 367    }
 368}
 369
 370fn handle_syskeyup_msg(
 371    wparam: WPARAM,
 372    lparam: LPARAM,
 373    state_ptr: Rc<WindowsWindowStatePtr>,
 374) -> Option<isize> {
 375    let mut lock = state_ptr.state.borrow_mut();
 376    let input = handle_key_event(wparam, lparam, &mut lock, |keystroke| {
 377        PlatformInput::KeyUp(KeyUpEvent { keystroke })
 378    })?;
 379    let mut func = lock.callbacks.input.take()?;
 380    drop(lock);
 381    func(input);
 382    state_ptr.state.borrow_mut().callbacks.input = Some(func);
 383
 384    // Always return 0 to indicate that the message was handled, so we could properly handle `ModifiersChanged` event.
 385    Some(0)
 386}
 387
 388// It's a known bug that you can't trigger `ctrl-shift-0`. See:
 389// https://superuser.com/questions/1455762/ctrl-shift-number-key-combination-has-stopped-working-for-a-few-numbers
 390fn handle_keydown_msg(
 391    wparam: WPARAM,
 392    lparam: LPARAM,
 393    state_ptr: Rc<WindowsWindowStatePtr>,
 394) -> Option<isize> {
 395    let mut lock = state_ptr.state.borrow_mut();
 396    let Some(input) = handle_key_event(wparam, lparam, &mut lock, |keystroke| {
 397        PlatformInput::KeyDown(KeyDownEvent {
 398            keystroke,
 399            is_held: lparam.0 & (0x1 << 30) > 0,
 400        })
 401    }) else {
 402        return Some(1);
 403    };
 404
 405    let Some(mut func) = lock.callbacks.input.take() else {
 406        return Some(1);
 407    };
 408    drop(lock);
 409
 410    let handled = !func(input).propagate;
 411
 412    let mut lock = state_ptr.state.borrow_mut();
 413    lock.callbacks.input = Some(func);
 414
 415    if handled {
 416        lock.suppress_next_char_msg = true;
 417        Some(0)
 418    } else {
 419        Some(1)
 420    }
 421}
 422
 423fn handle_keyup_msg(
 424    wparam: WPARAM,
 425    lparam: LPARAM,
 426    state_ptr: Rc<WindowsWindowStatePtr>,
 427) -> Option<isize> {
 428    let mut lock = state_ptr.state.borrow_mut();
 429    let Some(input) = handle_key_event(wparam, lparam, &mut lock, |keystroke| {
 430        PlatformInput::KeyUp(KeyUpEvent { keystroke })
 431    }) else {
 432        return Some(1);
 433    };
 434
 435    let Some(mut func) = lock.callbacks.input.take() else {
 436        return Some(1);
 437    };
 438    drop(lock);
 439
 440    let handled = !func(input).propagate;
 441    state_ptr.state.borrow_mut().callbacks.input = Some(func);
 442
 443    if handled { Some(0) } else { Some(1) }
 444}
 445
 446fn handle_char_msg(wparam: WPARAM, state_ptr: Rc<WindowsWindowStatePtr>) -> Option<isize> {
 447    let Some(input) = char::from_u32(wparam.0 as u32)
 448        .filter(|c| !c.is_control())
 449        .map(String::from)
 450    else {
 451        return Some(1);
 452    };
 453    with_input_handler(&state_ptr, |input_handler| {
 454        input_handler.replace_text_in_range(None, &input);
 455    });
 456
 457    Some(0)
 458}
 459
 460fn handle_dead_char_msg(wparam: WPARAM, state_ptr: Rc<WindowsWindowStatePtr>) -> Option<isize> {
 461    let ch = char::from_u32(wparam.0 as u32)?.to_string();
 462    with_input_handler(&state_ptr, |input_handler| {
 463        input_handler.replace_and_mark_text_in_range(None, &ch, None);
 464    });
 465    None
 466}
 467
 468fn handle_mouse_down_msg(
 469    handle: HWND,
 470    button: MouseButton,
 471    lparam: LPARAM,
 472    state_ptr: Rc<WindowsWindowStatePtr>,
 473) -> Option<isize> {
 474    unsafe { SetCapture(handle) };
 475    let mut lock = state_ptr.state.borrow_mut();
 476    let Some(mut func) = lock.callbacks.input.take() else {
 477        return Some(1);
 478    };
 479    let x = lparam.signed_loword();
 480    let y = lparam.signed_hiword();
 481    let physical_point = point(DevicePixels(x as i32), DevicePixels(y as i32));
 482    let click_count = lock.click_state.update(button, physical_point);
 483    let scale_factor = lock.scale_factor;
 484    drop(lock);
 485
 486    let input = PlatformInput::MouseDown(MouseDownEvent {
 487        button,
 488        position: logical_point(x as f32, y as f32, scale_factor),
 489        modifiers: current_modifiers(),
 490        click_count,
 491        first_mouse: false,
 492    });
 493    let handled = !func(input).propagate;
 494    state_ptr.state.borrow_mut().callbacks.input = Some(func);
 495
 496    if handled { Some(0) } else { Some(1) }
 497}
 498
 499fn handle_mouse_up_msg(
 500    _handle: HWND,
 501    button: MouseButton,
 502    lparam: LPARAM,
 503    state_ptr: Rc<WindowsWindowStatePtr>,
 504) -> Option<isize> {
 505    unsafe { ReleaseCapture().log_err() };
 506    let mut lock = state_ptr.state.borrow_mut();
 507    let Some(mut func) = lock.callbacks.input.take() else {
 508        return Some(1);
 509    };
 510    let x = lparam.signed_loword() as f32;
 511    let y = lparam.signed_hiword() as f32;
 512    let click_count = lock.click_state.current_count;
 513    let scale_factor = lock.scale_factor;
 514    drop(lock);
 515
 516    let input = PlatformInput::MouseUp(MouseUpEvent {
 517        button,
 518        position: logical_point(x, y, scale_factor),
 519        modifiers: current_modifiers(),
 520        click_count,
 521    });
 522    let handled = !func(input).propagate;
 523    state_ptr.state.borrow_mut().callbacks.input = Some(func);
 524
 525    if handled { Some(0) } else { Some(1) }
 526}
 527
 528fn handle_xbutton_msg(
 529    handle: HWND,
 530    wparam: WPARAM,
 531    lparam: LPARAM,
 532    handler: impl Fn(HWND, MouseButton, LPARAM, Rc<WindowsWindowStatePtr>) -> Option<isize>,
 533    state_ptr: Rc<WindowsWindowStatePtr>,
 534) -> Option<isize> {
 535    let nav_dir = match wparam.hiword() {
 536        XBUTTON1 => NavigationDirection::Back,
 537        XBUTTON2 => NavigationDirection::Forward,
 538        _ => return Some(1),
 539    };
 540    handler(handle, MouseButton::Navigate(nav_dir), lparam, state_ptr)
 541}
 542
 543fn handle_mouse_wheel_msg(
 544    handle: HWND,
 545    wparam: WPARAM,
 546    lparam: LPARAM,
 547    state_ptr: Rc<WindowsWindowStatePtr>,
 548) -> Option<isize> {
 549    let modifiers = current_modifiers();
 550    let mut lock = state_ptr.state.borrow_mut();
 551    let Some(mut func) = lock.callbacks.input.take() else {
 552        return Some(1);
 553    };
 554    let scale_factor = lock.scale_factor;
 555    let wheel_scroll_amount = match modifiers.shift {
 556        true => lock.system_settings.mouse_wheel_settings.wheel_scroll_chars,
 557        false => lock.system_settings.mouse_wheel_settings.wheel_scroll_lines,
 558    };
 559    drop(lock);
 560
 561    let wheel_distance =
 562        (wparam.signed_hiword() as f32 / WHEEL_DELTA as f32) * wheel_scroll_amount as f32;
 563    let mut cursor_point = POINT {
 564        x: lparam.signed_loword().into(),
 565        y: lparam.signed_hiword().into(),
 566    };
 567    unsafe { ScreenToClient(handle, &mut cursor_point).ok().log_err() };
 568    let input = PlatformInput::ScrollWheel(ScrollWheelEvent {
 569        position: logical_point(cursor_point.x as f32, cursor_point.y as f32, scale_factor),
 570        delta: ScrollDelta::Lines(match modifiers.shift {
 571            true => Point {
 572                x: wheel_distance,
 573                y: 0.0,
 574            },
 575            false => Point {
 576                y: wheel_distance,
 577                x: 0.0,
 578            },
 579        }),
 580        modifiers,
 581        touch_phase: TouchPhase::Moved,
 582    });
 583    let handled = !func(input).propagate;
 584    state_ptr.state.borrow_mut().callbacks.input = Some(func);
 585
 586    if handled { Some(0) } else { Some(1) }
 587}
 588
 589fn handle_mouse_horizontal_wheel_msg(
 590    handle: HWND,
 591    wparam: WPARAM,
 592    lparam: LPARAM,
 593    state_ptr: Rc<WindowsWindowStatePtr>,
 594) -> Option<isize> {
 595    let mut lock = state_ptr.state.borrow_mut();
 596    let Some(mut func) = lock.callbacks.input.take() else {
 597        return Some(1);
 598    };
 599    let scale_factor = lock.scale_factor;
 600    let wheel_scroll_chars = lock.system_settings.mouse_wheel_settings.wheel_scroll_chars;
 601    drop(lock);
 602
 603    let wheel_distance =
 604        (-wparam.signed_hiword() as f32 / WHEEL_DELTA as f32) * wheel_scroll_chars as f32;
 605    let mut cursor_point = POINT {
 606        x: lparam.signed_loword().into(),
 607        y: lparam.signed_hiword().into(),
 608    };
 609    unsafe { ScreenToClient(handle, &mut cursor_point).ok().log_err() };
 610    let event = PlatformInput::ScrollWheel(ScrollWheelEvent {
 611        position: logical_point(cursor_point.x as f32, cursor_point.y as f32, scale_factor),
 612        delta: ScrollDelta::Lines(Point {
 613            x: wheel_distance,
 614            y: 0.0,
 615        }),
 616        modifiers: current_modifiers(),
 617        touch_phase: TouchPhase::Moved,
 618    });
 619    let handled = !func(event).propagate;
 620    state_ptr.state.borrow_mut().callbacks.input = Some(func);
 621
 622    if handled { Some(0) } else { Some(1) }
 623}
 624
 625fn retrieve_caret_position(state_ptr: &Rc<WindowsWindowStatePtr>) -> Option<POINT> {
 626    with_input_handler_and_scale_factor(state_ptr, |input_handler, scale_factor| {
 627        let caret_range = input_handler.selected_text_range(false)?;
 628        let caret_position = input_handler.bounds_for_range(caret_range.range)?;
 629        Some(POINT {
 630            // logical to physical
 631            x: (caret_position.origin.x.0 * scale_factor) as i32,
 632            y: (caret_position.origin.y.0 * scale_factor) as i32
 633                + ((caret_position.size.height.0 * scale_factor) as i32 / 2),
 634        })
 635    })
 636}
 637
 638fn handle_ime_position(handle: HWND, state_ptr: Rc<WindowsWindowStatePtr>) -> Option<isize> {
 639    unsafe {
 640        let ctx = ImmGetContext(handle);
 641
 642        let Some(caret_position) = retrieve_caret_position(&state_ptr) else {
 643            return Some(0);
 644        };
 645        {
 646            let config = COMPOSITIONFORM {
 647                dwStyle: CFS_POINT,
 648                ptCurrentPos: caret_position,
 649                ..Default::default()
 650            };
 651            ImmSetCompositionWindow(ctx, &config as _).ok().log_err();
 652        }
 653        {
 654            let config = CANDIDATEFORM {
 655                dwStyle: CFS_CANDIDATEPOS,
 656                ptCurrentPos: caret_position,
 657                ..Default::default()
 658            };
 659            ImmSetCandidateWindow(ctx, &config as _).ok().log_err();
 660        }
 661        ImmReleaseContext(handle, ctx).ok().log_err();
 662        Some(0)
 663    }
 664}
 665
 666fn handle_ime_composition(
 667    handle: HWND,
 668    lparam: LPARAM,
 669    state_ptr: Rc<WindowsWindowStatePtr>,
 670) -> Option<isize> {
 671    let ctx = unsafe { ImmGetContext(handle) };
 672    let result = handle_ime_composition_inner(ctx, lparam, state_ptr);
 673    unsafe { ImmReleaseContext(handle, ctx).ok().log_err() };
 674    result
 675}
 676
 677fn handle_ime_composition_inner(
 678    ctx: HIMC,
 679    lparam: LPARAM,
 680    state_ptr: Rc<WindowsWindowStatePtr>,
 681) -> Option<isize> {
 682    let mut ime_input = None;
 683    if lparam.0 as u32 & GCS_COMPSTR.0 > 0 {
 684        let comp_string = parse_ime_compostion_string(ctx)?;
 685        with_input_handler(&state_ptr, |input_handler| {
 686            input_handler.replace_and_mark_text_in_range(None, &comp_string, None);
 687        })?;
 688        ime_input = Some(comp_string);
 689    }
 690    if lparam.0 as u32 & GCS_CURSORPOS.0 > 0 {
 691        let comp_string = &ime_input?;
 692        let caret_pos = retrieve_composition_cursor_position(ctx);
 693        with_input_handler(&state_ptr, |input_handler| {
 694            input_handler.replace_and_mark_text_in_range(
 695                None,
 696                comp_string,
 697                Some(caret_pos..caret_pos),
 698            );
 699        })?;
 700    }
 701    if lparam.0 as u32 & GCS_RESULTSTR.0 > 0 {
 702        let comp_result = parse_ime_compostion_result(ctx)?;
 703        with_input_handler(&state_ptr, |input_handler| {
 704            input_handler.replace_text_in_range(None, &comp_result);
 705        })?;
 706        return Some(0);
 707    }
 708    // currently, we don't care other stuff
 709    None
 710}
 711
 712/// SEE: https://learn.microsoft.com/en-us/windows/win32/winmsg/wm-nccalcsize
 713fn handle_calc_client_size(
 714    handle: HWND,
 715    wparam: WPARAM,
 716    lparam: LPARAM,
 717    state_ptr: Rc<WindowsWindowStatePtr>,
 718) -> Option<isize> {
 719    if !state_ptr.hide_title_bar || state_ptr.state.borrow().is_fullscreen() || wparam.0 == 0 {
 720        return None;
 721    }
 722
 723    let is_maximized = state_ptr.state.borrow().is_maximized();
 724    let insets = get_client_area_insets(handle, is_maximized, state_ptr.windows_version);
 725    // wparam is TRUE so lparam points to an NCCALCSIZE_PARAMS structure
 726    let mut params = lparam.0 as *mut NCCALCSIZE_PARAMS;
 727    let mut requested_client_rect = unsafe { &mut ((*params).rgrc) };
 728
 729    requested_client_rect[0].left += insets.left;
 730    requested_client_rect[0].top += insets.top;
 731    requested_client_rect[0].right -= insets.right;
 732    requested_client_rect[0].bottom -= insets.bottom;
 733
 734    // Fix auto hide taskbar not showing. This solution is based on the approach
 735    // used by Chrome. However, it may result in one row of pixels being obscured
 736    // in our client area. But as Chrome says, "there seems to be no better solution."
 737    if is_maximized {
 738        if let Some(ref taskbar_position) = state_ptr
 739            .state
 740            .borrow()
 741            .system_settings
 742            .auto_hide_taskbar_position
 743        {
 744            // Fot the auto-hide taskbar, adjust in by 1 pixel on taskbar edge,
 745            // so the window isn't treated as a "fullscreen app", which would cause
 746            // the taskbar to disappear.
 747            match taskbar_position {
 748                AutoHideTaskbarPosition::Left => {
 749                    requested_client_rect[0].left += AUTO_HIDE_TASKBAR_THICKNESS_PX
 750                }
 751                AutoHideTaskbarPosition::Top => {
 752                    requested_client_rect[0].top += AUTO_HIDE_TASKBAR_THICKNESS_PX
 753                }
 754                AutoHideTaskbarPosition::Right => {
 755                    requested_client_rect[0].right -= AUTO_HIDE_TASKBAR_THICKNESS_PX
 756                }
 757                AutoHideTaskbarPosition::Bottom => {
 758                    requested_client_rect[0].bottom -= AUTO_HIDE_TASKBAR_THICKNESS_PX
 759                }
 760            }
 761        }
 762    }
 763
 764    Some(0)
 765}
 766
 767fn handle_activate_msg(
 768    handle: HWND,
 769    wparam: WPARAM,
 770    state_ptr: Rc<WindowsWindowStatePtr>,
 771) -> Option<isize> {
 772    let activated = wparam.loword() > 0;
 773    if state_ptr.hide_title_bar {
 774        if let Some(titlebar_rect) = state_ptr.state.borrow().get_titlebar_rect().log_err() {
 775            unsafe {
 776                InvalidateRect(Some(handle), Some(&titlebar_rect), false)
 777                    .ok()
 778                    .log_err()
 779            };
 780        }
 781    }
 782    let this = state_ptr.clone();
 783    state_ptr
 784        .executor
 785        .spawn(async move {
 786            let mut lock = this.state.borrow_mut();
 787            if let Some(mut func) = lock.callbacks.active_status_change.take() {
 788                drop(lock);
 789                func(activated);
 790                this.state.borrow_mut().callbacks.active_status_change = Some(func);
 791            }
 792        })
 793        .detach();
 794
 795    None
 796}
 797
 798fn handle_create_msg(handle: HWND, state_ptr: Rc<WindowsWindowStatePtr>) -> Option<isize> {
 799    if state_ptr.hide_title_bar {
 800        notify_frame_changed(handle);
 801        Some(0)
 802    } else {
 803        None
 804    }
 805}
 806
 807fn handle_dpi_changed_msg(
 808    handle: HWND,
 809    wparam: WPARAM,
 810    lparam: LPARAM,
 811    state_ptr: Rc<WindowsWindowStatePtr>,
 812) -> Option<isize> {
 813    let new_dpi = wparam.loword() as f32;
 814    let mut lock = state_ptr.state.borrow_mut();
 815    lock.scale_factor = new_dpi / USER_DEFAULT_SCREEN_DPI as f32;
 816    lock.border_offset.update(handle).log_err();
 817    drop(lock);
 818
 819    let rect = unsafe { &*(lparam.0 as *const RECT) };
 820    let width = rect.right - rect.left;
 821    let height = rect.bottom - rect.top;
 822    // this will emit `WM_SIZE` and `WM_MOVE` right here
 823    // even before this function returns
 824    // the new size is handled in `WM_SIZE`
 825    unsafe {
 826        SetWindowPos(
 827            handle,
 828            None,
 829            rect.left,
 830            rect.top,
 831            width,
 832            height,
 833            SWP_NOZORDER | SWP_NOACTIVATE,
 834        )
 835        .context("unable to set window position after dpi has changed")
 836        .log_err();
 837    }
 838
 839    Some(0)
 840}
 841
 842/// The following conditions will trigger this event:
 843/// 1. The monitor on which the window is located goes offline or changes resolution.
 844/// 2. Another monitor goes offline, is plugged in, or changes resolution.
 845///
 846/// In either case, the window will only receive information from the monitor on which
 847/// it is located.
 848///
 849/// For example, in the case of condition 2, where the monitor on which the window is
 850/// located has actually changed nothing, it will still receive this event.
 851fn handle_display_change_msg(handle: HWND, state_ptr: Rc<WindowsWindowStatePtr>) -> Option<isize> {
 852    // NOTE:
 853    // Even the `lParam` holds the resolution of the screen, we just ignore it.
 854    // Because WM_DPICHANGED, WM_MOVE, WM_SIZE will come first, window reposition and resize
 855    // are handled there.
 856    // So we only care about if monitor is disconnected.
 857    let previous_monitor = state_ptr.state.borrow().display;
 858    if WindowsDisplay::is_connected(previous_monitor.handle) {
 859        // we are fine, other display changed
 860        return None;
 861    }
 862    // display disconnected
 863    // in this case, the OS will move our window to another monitor, and minimize it.
 864    // we deminimize the window and query the monitor after moving
 865    unsafe {
 866        let _ = ShowWindow(handle, SW_SHOWNORMAL);
 867    };
 868    let new_monitor = unsafe { MonitorFromWindow(handle, MONITOR_DEFAULTTONULL) };
 869    // all monitors disconnected
 870    if new_monitor.is_invalid() {
 871        log::error!("No monitor detected!");
 872        return None;
 873    }
 874    let new_display = WindowsDisplay::new_with_handle(new_monitor);
 875    state_ptr.state.borrow_mut().display = new_display;
 876    Some(0)
 877}
 878
 879fn handle_hit_test_msg(
 880    handle: HWND,
 881    msg: u32,
 882    wparam: WPARAM,
 883    lparam: LPARAM,
 884    state_ptr: Rc<WindowsWindowStatePtr>,
 885) -> Option<isize> {
 886    if !state_ptr.is_movable {
 887        return None;
 888    }
 889    if !state_ptr.hide_title_bar {
 890        return None;
 891    }
 892
 893    // default handler for resize areas
 894    let hit = unsafe { DefWindowProcW(handle, msg, wparam, lparam) };
 895    if matches!(
 896        hit.0 as u32,
 897        HTNOWHERE
 898            | HTRIGHT
 899            | HTLEFT
 900            | HTTOPLEFT
 901            | HTTOP
 902            | HTTOPRIGHT
 903            | HTBOTTOMRIGHT
 904            | HTBOTTOM
 905            | HTBOTTOMLEFT
 906    ) {
 907        return Some(hit.0);
 908    }
 909
 910    if state_ptr.state.borrow().is_fullscreen() {
 911        return Some(HTCLIENT as _);
 912    }
 913
 914    let dpi = unsafe { GetDpiForWindow(handle) };
 915    let frame_y = unsafe { GetSystemMetricsForDpi(SM_CYFRAME, dpi) };
 916
 917    let mut cursor_point = POINT {
 918        x: lparam.signed_loword().into(),
 919        y: lparam.signed_hiword().into(),
 920    };
 921    unsafe { ScreenToClient(handle, &mut cursor_point).ok().log_err() };
 922    if !state_ptr.state.borrow().is_maximized() && cursor_point.y >= 0 && cursor_point.y <= frame_y
 923    {
 924        return Some(HTTOP as _);
 925    }
 926
 927    let titlebar_rect = state_ptr.state.borrow().get_titlebar_rect();
 928    if let Ok(titlebar_rect) = titlebar_rect {
 929        if cursor_point.y < titlebar_rect.bottom {
 930            let caption_btn_width = (state_ptr.state.borrow().caption_button_width().0
 931                * state_ptr.state.borrow().scale_factor) as i32;
 932            if cursor_point.x >= titlebar_rect.right - caption_btn_width {
 933                return Some(HTCLOSE as _);
 934            } else if cursor_point.x >= titlebar_rect.right - caption_btn_width * 2 {
 935                return Some(HTMAXBUTTON as _);
 936            } else if cursor_point.x >= titlebar_rect.right - caption_btn_width * 3 {
 937                return Some(HTMINBUTTON as _);
 938            }
 939
 940            return Some(HTCAPTION as _);
 941        }
 942    }
 943
 944    Some(HTCLIENT as _)
 945}
 946
 947fn handle_nc_mouse_move_msg(
 948    handle: HWND,
 949    lparam: LPARAM,
 950    state_ptr: Rc<WindowsWindowStatePtr>,
 951) -> Option<isize> {
 952    if !state_ptr.hide_title_bar {
 953        return None;
 954    }
 955
 956    start_tracking_mouse(handle, &state_ptr, TME_LEAVE | TME_NONCLIENT);
 957
 958    let mut lock = state_ptr.state.borrow_mut();
 959    let mut func = lock.callbacks.input.take()?;
 960    let scale_factor = lock.scale_factor;
 961    drop(lock);
 962
 963    let mut cursor_point = POINT {
 964        x: lparam.signed_loword().into(),
 965        y: lparam.signed_hiword().into(),
 966    };
 967    unsafe { ScreenToClient(handle, &mut cursor_point).ok().log_err() };
 968    let input = PlatformInput::MouseMove(MouseMoveEvent {
 969        position: logical_point(cursor_point.x as f32, cursor_point.y as f32, scale_factor),
 970        pressed_button: None,
 971        modifiers: current_modifiers(),
 972    });
 973    let handled = !func(input).propagate;
 974    state_ptr.state.borrow_mut().callbacks.input = Some(func);
 975
 976    if handled { Some(0) } else { None }
 977}
 978
 979fn handle_nc_mouse_down_msg(
 980    handle: HWND,
 981    button: MouseButton,
 982    wparam: WPARAM,
 983    lparam: LPARAM,
 984    state_ptr: Rc<WindowsWindowStatePtr>,
 985) -> Option<isize> {
 986    if !state_ptr.hide_title_bar {
 987        return None;
 988    }
 989
 990    let mut lock = state_ptr.state.borrow_mut();
 991    if let Some(mut func) = lock.callbacks.input.take() {
 992        let scale_factor = lock.scale_factor;
 993        let mut cursor_point = POINT {
 994            x: lparam.signed_loword().into(),
 995            y: lparam.signed_hiword().into(),
 996        };
 997        unsafe { ScreenToClient(handle, &mut cursor_point).ok().log_err() };
 998        let physical_point = point(DevicePixels(cursor_point.x), DevicePixels(cursor_point.y));
 999        let click_count = lock.click_state.update(button, physical_point);
1000        drop(lock);
1001
1002        let input = PlatformInput::MouseDown(MouseDownEvent {
1003            button,
1004            position: logical_point(cursor_point.x as f32, cursor_point.y as f32, scale_factor),
1005            modifiers: current_modifiers(),
1006            click_count,
1007            first_mouse: false,
1008        });
1009        let result = func(input.clone());
1010        let handled = !result.propagate || result.default_prevented;
1011        state_ptr.state.borrow_mut().callbacks.input = Some(func);
1012
1013        if handled {
1014            return Some(0);
1015        }
1016    } else {
1017        drop(lock);
1018    };
1019
1020    // Since these are handled in handle_nc_mouse_up_msg we must prevent the default window proc
1021    if button == MouseButton::Left {
1022        match wparam.0 as u32 {
1023            HTMINBUTTON => state_ptr.state.borrow_mut().nc_button_pressed = Some(HTMINBUTTON),
1024            HTMAXBUTTON => state_ptr.state.borrow_mut().nc_button_pressed = Some(HTMAXBUTTON),
1025            HTCLOSE => state_ptr.state.borrow_mut().nc_button_pressed = Some(HTCLOSE),
1026            _ => return None,
1027        };
1028        Some(0)
1029    } else {
1030        None
1031    }
1032}
1033
1034fn handle_nc_mouse_up_msg(
1035    handle: HWND,
1036    button: MouseButton,
1037    wparam: WPARAM,
1038    lparam: LPARAM,
1039    state_ptr: Rc<WindowsWindowStatePtr>,
1040) -> Option<isize> {
1041    if !state_ptr.hide_title_bar {
1042        return None;
1043    }
1044
1045    let mut lock = state_ptr.state.borrow_mut();
1046    if let Some(mut func) = lock.callbacks.input.take() {
1047        let scale_factor = lock.scale_factor;
1048        drop(lock);
1049
1050        let mut cursor_point = POINT {
1051            x: lparam.signed_loword().into(),
1052            y: lparam.signed_hiword().into(),
1053        };
1054        unsafe { ScreenToClient(handle, &mut cursor_point).ok().log_err() };
1055        let input = PlatformInput::MouseUp(MouseUpEvent {
1056            button,
1057            position: logical_point(cursor_point.x as f32, cursor_point.y as f32, scale_factor),
1058            modifiers: current_modifiers(),
1059            click_count: 1,
1060        });
1061        let handled = !func(input).propagate;
1062        state_ptr.state.borrow_mut().callbacks.input = Some(func);
1063
1064        if handled {
1065            return Some(0);
1066        }
1067    } else {
1068        drop(lock);
1069    }
1070
1071    let last_pressed = state_ptr.state.borrow_mut().nc_button_pressed.take();
1072    if button == MouseButton::Left && last_pressed.is_some() {
1073        let handled = match (wparam.0 as u32, last_pressed.unwrap()) {
1074            (HTMINBUTTON, HTMINBUTTON) => {
1075                unsafe { ShowWindowAsync(handle, SW_MINIMIZE).ok().log_err() };
1076                true
1077            }
1078            (HTMAXBUTTON, HTMAXBUTTON) => {
1079                if state_ptr.state.borrow().is_maximized() {
1080                    unsafe { ShowWindowAsync(handle, SW_NORMAL).ok().log_err() };
1081                } else {
1082                    unsafe { ShowWindowAsync(handle, SW_MAXIMIZE).ok().log_err() };
1083                }
1084                true
1085            }
1086            (HTCLOSE, HTCLOSE) => {
1087                unsafe {
1088                    PostMessageW(Some(handle), WM_CLOSE, WPARAM::default(), LPARAM::default())
1089                        .log_err()
1090                };
1091                true
1092            }
1093            _ => false,
1094        };
1095        if handled {
1096            return Some(0);
1097        }
1098    }
1099
1100    None
1101}
1102
1103fn handle_cursor_changed(lparam: LPARAM, state_ptr: Rc<WindowsWindowStatePtr>) -> Option<isize> {
1104    let mut state = state_ptr.state.borrow_mut();
1105    let had_cursor = state.current_cursor.is_some();
1106
1107    state.current_cursor = if lparam.0 == 0 {
1108        None
1109    } else {
1110        Some(HCURSOR(lparam.0 as _))
1111    };
1112
1113    if had_cursor != state.current_cursor.is_some() {
1114        unsafe { SetCursor(state.current_cursor) };
1115    }
1116
1117    Some(0)
1118}
1119
1120fn handle_set_cursor(lparam: LPARAM, state_ptr: Rc<WindowsWindowStatePtr>) -> Option<isize> {
1121    if matches!(
1122        lparam.loword() as u32,
1123        HTLEFT | HTRIGHT | HTTOP | HTTOPLEFT | HTTOPRIGHT | HTBOTTOM | HTBOTTOMLEFT | HTBOTTOMRIGHT
1124    ) {
1125        return None;
1126    }
1127    unsafe {
1128        SetCursor(state_ptr.state.borrow().current_cursor);
1129    };
1130    Some(1)
1131}
1132
1133fn handle_system_settings_changed(
1134    handle: HWND,
1135    lparam: LPARAM,
1136    state_ptr: Rc<WindowsWindowStatePtr>,
1137) -> Option<isize> {
1138    let mut lock = state_ptr.state.borrow_mut();
1139    let display = lock.display;
1140    // system settings
1141    lock.system_settings.update(display);
1142    // mouse double click
1143    lock.click_state.system_update();
1144    // window border offset
1145    lock.border_offset.update(handle).log_err();
1146    drop(lock);
1147
1148    // lParam is a pointer to a string that indicates the area containing the system parameter
1149    // that was changed.
1150    let parameter = PCWSTR::from_raw(lparam.0 as _);
1151    if unsafe { !parameter.is_null() && !parameter.is_empty() } {
1152        if let Some(parameter_string) = unsafe { parameter.to_string() }.log_err() {
1153            log::info!("System settings changed: {}", parameter_string);
1154            match parameter_string.as_str() {
1155                "ImmersiveColorSet" => {
1156                    handle_system_theme_changed(handle, state_ptr);
1157                }
1158                _ => {}
1159            }
1160        }
1161    }
1162
1163    // Force to trigger WM_NCCALCSIZE event to ensure that we handle auto hide
1164    // taskbar correctly.
1165    notify_frame_changed(handle);
1166    Some(0)
1167}
1168
1169fn handle_system_command(wparam: WPARAM, state_ptr: Rc<WindowsWindowStatePtr>) -> Option<isize> {
1170    if wparam.0 == SC_KEYMENU as usize {
1171        let mut lock = state_ptr.state.borrow_mut();
1172        if lock.system_key_handled {
1173            lock.system_key_handled = false;
1174            return Some(0);
1175        }
1176    }
1177    None
1178}
1179
1180fn handle_system_theme_changed(
1181    handle: HWND,
1182    state_ptr: Rc<WindowsWindowStatePtr>,
1183) -> Option<isize> {
1184    let mut callback = state_ptr
1185        .state
1186        .borrow_mut()
1187        .callbacks
1188        .appearance_changed
1189        .take()?;
1190    callback();
1191    state_ptr.state.borrow_mut().callbacks.appearance_changed = Some(callback);
1192    configure_dwm_dark_mode(handle);
1193    Some(0)
1194}
1195
1196fn handle_input_language_changed(
1197    lparam: LPARAM,
1198    state_ptr: Rc<WindowsWindowStatePtr>,
1199) -> Option<isize> {
1200    let thread = state_ptr.main_thread_id_win32;
1201    let validation = state_ptr.validation_number;
1202    unsafe {
1203        PostThreadMessageW(thread, WM_INPUTLANGCHANGE, WPARAM(validation), lparam).log_err();
1204    }
1205    Some(0)
1206}
1207
1208fn handle_key_event<F>(
1209    wparam: WPARAM,
1210    lparam: LPARAM,
1211    state: &mut WindowsWindowState,
1212    f: F,
1213) -> Option<PlatformInput>
1214where
1215    F: FnOnce(Keystroke) -> PlatformInput,
1216{
1217    state.suppress_next_char_msg = false;
1218    let virtual_key = VIRTUAL_KEY(wparam.loword());
1219    let mut modifiers = current_modifiers();
1220
1221    match virtual_key {
1222        VK_PROCESSKEY => {
1223            // IME composition
1224            None
1225        }
1226        VK_SHIFT | VK_CONTROL | VK_MENU | VK_LWIN | VK_RWIN => {
1227            if state
1228                .last_reported_modifiers
1229                .is_some_and(|prev_modifiers| prev_modifiers == modifiers)
1230            {
1231                return None;
1232            }
1233            state.last_reported_modifiers = Some(modifiers);
1234            Some(PlatformInput::ModifiersChanged(ModifiersChangedEvent {
1235                modifiers,
1236            }))
1237        }
1238        vkey => {
1239            let keystroke = parse_normal_key(vkey, lparam, modifiers)?;
1240            Some(f(keystroke))
1241        }
1242    }
1243}
1244
1245fn parse_immutable(vkey: VIRTUAL_KEY) -> Option<String> {
1246    Some(
1247        match vkey {
1248            VK_SPACE => "space",
1249            VK_BACK => "backspace",
1250            VK_RETURN => "enter",
1251            VK_TAB => "tab",
1252            VK_UP => "up",
1253            VK_DOWN => "down",
1254            VK_RIGHT => "right",
1255            VK_LEFT => "left",
1256            VK_HOME => "home",
1257            VK_END => "end",
1258            VK_PRIOR => "pageup",
1259            VK_NEXT => "pagedown",
1260            VK_BROWSER_BACK => "back",
1261            VK_BROWSER_FORWARD => "forward",
1262            VK_ESCAPE => "escape",
1263            VK_INSERT => "insert",
1264            VK_DELETE => "delete",
1265            VK_APPS => "menu",
1266            VK_F1 => "f1",
1267            VK_F2 => "f2",
1268            VK_F3 => "f3",
1269            VK_F4 => "f4",
1270            VK_F5 => "f5",
1271            VK_F6 => "f6",
1272            VK_F7 => "f7",
1273            VK_F8 => "f8",
1274            VK_F9 => "f9",
1275            VK_F10 => "f10",
1276            VK_F11 => "f11",
1277            VK_F12 => "f12",
1278            VK_F13 => "f13",
1279            VK_F14 => "f14",
1280            VK_F15 => "f15",
1281            VK_F16 => "f16",
1282            VK_F17 => "f17",
1283            VK_F18 => "f18",
1284            VK_F19 => "f19",
1285            VK_F20 => "f20",
1286            VK_F21 => "f21",
1287            VK_F22 => "f22",
1288            VK_F23 => "f23",
1289            VK_F24 => "f24",
1290            _ => return None,
1291        }
1292        .to_string(),
1293    )
1294}
1295
1296fn parse_normal_key(
1297    vkey: VIRTUAL_KEY,
1298    lparam: LPARAM,
1299    mut modifiers: Modifiers,
1300) -> Option<Keystroke> {
1301    let mut key_char = None;
1302    let key = parse_immutable(vkey).or_else(|| {
1303        let scan_code = lparam.hiword() & 0xFF;
1304        key_char = generate_key_char(
1305            vkey,
1306            scan_code as u32,
1307            modifiers.control,
1308            modifiers.shift,
1309            modifiers.alt,
1310        );
1311        get_keystroke_key(vkey, scan_code as u32, &mut modifiers)
1312    })?;
1313    Some(Keystroke {
1314        modifiers,
1315        key,
1316        key_char,
1317    })
1318}
1319
1320fn parse_ime_compostion_string(ctx: HIMC) -> Option<String> {
1321    unsafe {
1322        let string_len = ImmGetCompositionStringW(ctx, GCS_COMPSTR, None, 0);
1323        if string_len >= 0 {
1324            let mut buffer = vec![0u8; string_len as usize + 2];
1325            ImmGetCompositionStringW(
1326                ctx,
1327                GCS_COMPSTR,
1328                Some(buffer.as_mut_ptr() as _),
1329                string_len as _,
1330            );
1331            let wstring = std::slice::from_raw_parts::<u16>(
1332                buffer.as_mut_ptr().cast::<u16>(),
1333                string_len as usize / 2,
1334            );
1335            Some(String::from_utf16_lossy(wstring))
1336        } else {
1337            None
1338        }
1339    }
1340}
1341
1342#[inline]
1343fn retrieve_composition_cursor_position(ctx: HIMC) -> usize {
1344    unsafe { ImmGetCompositionStringW(ctx, GCS_CURSORPOS, None, 0) as usize }
1345}
1346
1347fn parse_ime_compostion_result(ctx: HIMC) -> Option<String> {
1348    unsafe {
1349        let string_len = ImmGetCompositionStringW(ctx, GCS_RESULTSTR, None, 0);
1350        if string_len >= 0 {
1351            let mut buffer = vec![0u8; string_len as usize + 2];
1352            ImmGetCompositionStringW(
1353                ctx,
1354                GCS_RESULTSTR,
1355                Some(buffer.as_mut_ptr() as _),
1356                string_len as _,
1357            );
1358            let wstring = std::slice::from_raw_parts::<u16>(
1359                buffer.as_mut_ptr().cast::<u16>(),
1360                string_len as usize / 2,
1361            );
1362            let string = String::from_utf16_lossy(wstring);
1363            Some(string)
1364        } else {
1365            None
1366        }
1367    }
1368}
1369
1370#[inline]
1371fn is_virtual_key_pressed(vkey: VIRTUAL_KEY) -> bool {
1372    unsafe { GetKeyState(vkey.0 as i32) < 0 }
1373}
1374
1375#[inline]
1376pub(crate) fn current_modifiers() -> Modifiers {
1377    Modifiers {
1378        control: is_virtual_key_pressed(VK_CONTROL),
1379        alt: is_virtual_key_pressed(VK_MENU),
1380        shift: is_virtual_key_pressed(VK_SHIFT),
1381        platform: is_virtual_key_pressed(VK_LWIN) || is_virtual_key_pressed(VK_RWIN),
1382        function: false,
1383    }
1384}
1385
1386fn get_client_area_insets(
1387    handle: HWND,
1388    is_maximized: bool,
1389    windows_version: WindowsVersion,
1390) -> RECT {
1391    // For maximized windows, Windows outdents the window rect from the screen's client rect
1392    // by `frame_thickness` on each edge, meaning `insets` must contain `frame_thickness`
1393    // on all sides (including the top) to avoid the client area extending onto adjacent
1394    // monitors.
1395    //
1396    // For non-maximized windows, things become complicated:
1397    //
1398    // - On Windows 10
1399    // The top inset must be zero, since if there is any nonclient area, Windows will draw
1400    // a full native titlebar outside the client area. (This doesn't occur in the maximized
1401    // case.)
1402    //
1403    // - On Windows 11
1404    // The top inset is calculated using an empirical formula that I derived through various
1405    // tests. Without this, the top 1-2 rows of pixels in our window would be obscured.
1406    let dpi = unsafe { GetDpiForWindow(handle) };
1407    let frame_thickness = get_frame_thickness(dpi);
1408    let top_insets = if is_maximized {
1409        frame_thickness
1410    } else {
1411        match windows_version {
1412            WindowsVersion::Win10 => 0,
1413            WindowsVersion::Win11 => (dpi as f32 / USER_DEFAULT_SCREEN_DPI as f32).round() as i32,
1414        }
1415    };
1416    RECT {
1417        left: frame_thickness,
1418        top: top_insets,
1419        right: frame_thickness,
1420        bottom: frame_thickness,
1421    }
1422}
1423
1424// there is some additional non-visible space when talking about window
1425// borders on Windows:
1426// - SM_CXSIZEFRAME: The resize handle.
1427// - SM_CXPADDEDBORDER: Additional border space that isn't part of the resize handle.
1428fn get_frame_thickness(dpi: u32) -> i32 {
1429    let resize_frame_thickness = unsafe { GetSystemMetricsForDpi(SM_CXSIZEFRAME, dpi) };
1430    let padding_thickness = unsafe { GetSystemMetricsForDpi(SM_CXPADDEDBORDER, dpi) };
1431    resize_frame_thickness + padding_thickness
1432}
1433
1434fn notify_frame_changed(handle: HWND) {
1435    unsafe {
1436        SetWindowPos(
1437            handle,
1438            None,
1439            0,
1440            0,
1441            0,
1442            0,
1443            SWP_FRAMECHANGED
1444                | SWP_NOACTIVATE
1445                | SWP_NOCOPYBITS
1446                | SWP_NOMOVE
1447                | SWP_NOOWNERZORDER
1448                | SWP_NOREPOSITION
1449                | SWP_NOSENDCHANGING
1450                | SWP_NOSIZE
1451                | SWP_NOZORDER,
1452        )
1453        .log_err();
1454    }
1455}
1456
1457fn start_tracking_mouse(
1458    handle: HWND,
1459    state_ptr: &Rc<WindowsWindowStatePtr>,
1460    flags: TRACKMOUSEEVENT_FLAGS,
1461) {
1462    let mut lock = state_ptr.state.borrow_mut();
1463    if !lock.hovered {
1464        lock.hovered = true;
1465        unsafe {
1466            TrackMouseEvent(&mut TRACKMOUSEEVENT {
1467                cbSize: std::mem::size_of::<TRACKMOUSEEVENT>() as u32,
1468                dwFlags: flags,
1469                hwndTrack: handle,
1470                dwHoverTime: HOVER_DEFAULT,
1471            })
1472            .log_err()
1473        };
1474        if let Some(mut callback) = lock.callbacks.hovered_status_change.take() {
1475            drop(lock);
1476            callback(true);
1477            state_ptr.state.borrow_mut().callbacks.hovered_status_change = Some(callback);
1478        }
1479    }
1480}
1481
1482fn with_input_handler<F, R>(state_ptr: &Rc<WindowsWindowStatePtr>, f: F) -> Option<R>
1483where
1484    F: FnOnce(&mut PlatformInputHandler) -> R,
1485{
1486    let mut lock = state_ptr.state.borrow_mut();
1487    if lock.suppress_next_char_msg {
1488        return None;
1489    }
1490    let mut input_handler = lock.input_handler.take()?;
1491    drop(lock);
1492    let result = f(&mut input_handler);
1493    state_ptr.state.borrow_mut().input_handler = Some(input_handler);
1494    Some(result)
1495}
1496
1497fn with_input_handler_and_scale_factor<F, R>(
1498    state_ptr: &Rc<WindowsWindowStatePtr>,
1499    f: F,
1500) -> Option<R>
1501where
1502    F: FnOnce(&mut PlatformInputHandler, f32) -> Option<R>,
1503{
1504    let mut lock = state_ptr.state.borrow_mut();
1505    if lock.suppress_next_char_msg {
1506        return None;
1507    }
1508    let mut input_handler = lock.input_handler.take()?;
1509    let scale_factor = lock.scale_factor;
1510    drop(lock);
1511    let result = f(&mut input_handler, scale_factor);
1512    state_ptr.state.borrow_mut().input_handler = Some(input_handler);
1513    result
1514}