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;
  26pub(crate) const WM_GPUI_FORCE_UPDATE_WINDOW: u32 = WM_USER + 5;
  27
  28const SIZE_MOVE_LOOP_TIMER_ID: usize = 1;
  29const AUTO_HIDE_TASKBAR_THICKNESS_PX: i32 = 1;
  30
  31pub(crate) fn handle_msg(
  32    handle: HWND,
  33    msg: u32,
  34    wparam: WPARAM,
  35    lparam: LPARAM,
  36    state_ptr: Rc<WindowsWindowStatePtr>,
  37) -> LRESULT {
  38    let handled = match msg {
  39        WM_ACTIVATE => handle_activate_msg(wparam, state_ptr),
  40        WM_CREATE => handle_create_msg(handle, state_ptr),
  41        WM_DEVICECHANGE => handle_device_change_msg(handle, wparam, state_ptr),
  42        WM_MOVE => handle_move_msg(handle, lparam, state_ptr),
  43        WM_SIZE => handle_size_msg(wparam, lparam, state_ptr),
  44        WM_GETMINMAXINFO => handle_get_min_max_info_msg(lparam, state_ptr),
  45        WM_ENTERSIZEMOVE | WM_ENTERMENULOOP => handle_size_move_loop(handle),
  46        WM_EXITSIZEMOVE | WM_EXITMENULOOP => handle_size_move_loop_exit(handle),
  47        WM_TIMER => handle_timer_msg(handle, wparam, state_ptr),
  48        WM_NCCALCSIZE => handle_calc_client_size(handle, wparam, lparam, state_ptr),
  49        WM_DPICHANGED => handle_dpi_changed_msg(handle, wparam, lparam, state_ptr),
  50        WM_DISPLAYCHANGE => handle_display_change_msg(handle, state_ptr),
  51        WM_NCHITTEST => handle_hit_test_msg(handle, msg, wparam, lparam, state_ptr),
  52        WM_PAINT => handle_paint_msg(handle, state_ptr),
  53        WM_CLOSE => handle_close_msg(state_ptr),
  54        WM_DESTROY => handle_destroy_msg(handle, state_ptr),
  55        WM_MOUSEMOVE => handle_mouse_move_msg(handle, lparam, wparam, state_ptr),
  56        WM_MOUSELEAVE | WM_NCMOUSELEAVE => handle_mouse_leave_msg(state_ptr),
  57        WM_NCMOUSEMOVE => handle_nc_mouse_move_msg(handle, lparam, state_ptr),
  58        WM_NCLBUTTONDOWN => {
  59            handle_nc_mouse_down_msg(handle, MouseButton::Left, wparam, lparam, state_ptr)
  60        }
  61        WM_NCRBUTTONDOWN => {
  62            handle_nc_mouse_down_msg(handle, MouseButton::Right, wparam, lparam, state_ptr)
  63        }
  64        WM_NCMBUTTONDOWN => {
  65            handle_nc_mouse_down_msg(handle, MouseButton::Middle, wparam, lparam, state_ptr)
  66        }
  67        WM_NCLBUTTONUP => {
  68            handle_nc_mouse_up_msg(handle, MouseButton::Left, wparam, lparam, state_ptr)
  69        }
  70        WM_NCRBUTTONUP => {
  71            handle_nc_mouse_up_msg(handle, MouseButton::Right, wparam, lparam, state_ptr)
  72        }
  73        WM_NCMBUTTONUP => {
  74            handle_nc_mouse_up_msg(handle, MouseButton::Middle, wparam, lparam, state_ptr)
  75        }
  76        WM_LBUTTONDOWN => handle_mouse_down_msg(handle, MouseButton::Left, lparam, state_ptr),
  77        WM_RBUTTONDOWN => handle_mouse_down_msg(handle, MouseButton::Right, lparam, state_ptr),
  78        WM_MBUTTONDOWN => handle_mouse_down_msg(handle, MouseButton::Middle, lparam, state_ptr),
  79        WM_XBUTTONDOWN => {
  80            handle_xbutton_msg(handle, wparam, lparam, handle_mouse_down_msg, state_ptr)
  81        }
  82        WM_LBUTTONUP => handle_mouse_up_msg(handle, MouseButton::Left, lparam, state_ptr),
  83        WM_RBUTTONUP => handle_mouse_up_msg(handle, MouseButton::Right, lparam, state_ptr),
  84        WM_MBUTTONUP => handle_mouse_up_msg(handle, MouseButton::Middle, lparam, state_ptr),
  85        WM_XBUTTONUP => handle_xbutton_msg(handle, wparam, lparam, handle_mouse_up_msg, state_ptr),
  86        WM_MOUSEWHEEL => handle_mouse_wheel_msg(handle, wparam, lparam, state_ptr),
  87        WM_MOUSEHWHEEL => handle_mouse_horizontal_wheel_msg(handle, wparam, lparam, state_ptr),
  88        WM_SYSKEYDOWN => handle_syskeydown_msg(handle, wparam, lparam, state_ptr),
  89        WM_SYSKEYUP => handle_syskeyup_msg(handle, wparam, lparam, state_ptr),
  90        WM_SYSCOMMAND => handle_system_command(wparam, state_ptr),
  91        WM_KEYDOWN => handle_keydown_msg(handle, wparam, lparam, state_ptr),
  92        WM_KEYUP => handle_keyup_msg(handle, wparam, lparam, state_ptr),
  93        WM_CHAR => handle_char_msg(wparam, state_ptr),
  94        WM_DEADCHAR => handle_dead_char_msg(wparam, state_ptr),
  95        WM_IME_STARTCOMPOSITION => handle_ime_position(handle, state_ptr),
  96        WM_IME_COMPOSITION => handle_ime_composition(handle, lparam, state_ptr),
  97        WM_SETCURSOR => handle_set_cursor(handle, lparam, state_ptr),
  98        WM_SETTINGCHANGE => handle_system_settings_changed(handle, wparam, lparam, state_ptr),
  99        WM_INPUTLANGCHANGE => handle_input_language_changed(lparam, state_ptr),
 100        WM_GPUI_CURSOR_STYLE_CHANGED => handle_cursor_changed(lparam, state_ptr),
 101        WM_GPUI_FORCE_UPDATE_WINDOW => draw_window(handle, true, state_ptr),
 102        _ => None,
 103    };
 104    if let Some(n) = handled {
 105        LRESULT(n)
 106    } else {
 107        unsafe { DefWindowProcW(handle, msg, wparam, lparam) }
 108    }
 109}
 110
 111fn handle_move_msg(
 112    handle: HWND,
 113    lparam: LPARAM,
 114    state_ptr: Rc<WindowsWindowStatePtr>,
 115) -> Option<isize> {
 116    let mut lock = state_ptr.state.borrow_mut();
 117    let origin = logical_point(
 118        lparam.signed_loword() as f32,
 119        lparam.signed_hiword() as f32,
 120        lock.scale_factor,
 121    );
 122    lock.origin = origin;
 123    let size = lock.logical_size;
 124    let center_x = origin.x.0 + size.width.0 / 2.;
 125    let center_y = origin.y.0 + size.height.0 / 2.;
 126    let monitor_bounds = lock.display.bounds();
 127    if center_x < monitor_bounds.left().0
 128        || center_x > monitor_bounds.right().0
 129        || center_y < monitor_bounds.top().0
 130        || center_y > monitor_bounds.bottom().0
 131    {
 132        // center of the window may have moved to another monitor
 133        let monitor = unsafe { MonitorFromWindow(handle, MONITOR_DEFAULTTONULL) };
 134        // minimize the window can trigger this event too, in this case,
 135        // monitor is invalid, we do nothing.
 136        if !monitor.is_invalid() && lock.display.handle != monitor {
 137            // we will get the same monitor if we only have one
 138            lock.display = WindowsDisplay::new_with_handle(monitor);
 139        }
 140    }
 141    if let Some(mut callback) = lock.callbacks.moved.take() {
 142        drop(lock);
 143        callback();
 144        state_ptr.state.borrow_mut().callbacks.moved = Some(callback);
 145    }
 146    Some(0)
 147}
 148
 149fn handle_get_min_max_info_msg(
 150    lparam: LPARAM,
 151    state_ptr: Rc<WindowsWindowStatePtr>,
 152) -> Option<isize> {
 153    let lock = state_ptr.state.borrow();
 154    let min_size = lock.min_size?;
 155    let scale_factor = lock.scale_factor;
 156    let boarder_offset = lock.border_offset;
 157    drop(lock);
 158    unsafe {
 159        let minmax_info = &mut *(lparam.0 as *mut MINMAXINFO);
 160        minmax_info.ptMinTrackSize.x =
 161            min_size.width.scale(scale_factor).0 as i32 + boarder_offset.width_offset;
 162        minmax_info.ptMinTrackSize.y =
 163            min_size.height.scale(scale_factor).0 as i32 + boarder_offset.height_offset;
 164    }
 165    Some(0)
 166}
 167
 168fn handle_size_msg(
 169    wparam: WPARAM,
 170    lparam: LPARAM,
 171    state_ptr: Rc<WindowsWindowStatePtr>,
 172) -> Option<isize> {
 173    let mut lock = state_ptr.state.borrow_mut();
 174
 175    // Don't resize the renderer when the window is minimized, but record that it was minimized so
 176    // that on restore the swap chain can be recreated via `update_drawable_size_even_if_unchanged`.
 177    if wparam.0 == SIZE_MINIMIZED as usize {
 178        lock.restore_from_minimized = lock.callbacks.request_frame.take();
 179        return Some(0);
 180    }
 181
 182    let width = lparam.loword().max(1) as i32;
 183    let height = lparam.hiword().max(1) as i32;
 184    let new_size = size(DevicePixels(width), DevicePixels(height));
 185    let scale_factor = lock.scale_factor;
 186    if lock.restore_from_minimized.is_some() {
 187        lock.callbacks.request_frame = lock.restore_from_minimized.take();
 188    } else {
 189        lock.renderer.resize(new_size).log_err();
 190    }
 191    let new_size = new_size.to_pixels(scale_factor);
 192    lock.logical_size = new_size;
 193    if let Some(mut callback) = lock.callbacks.resize.take() {
 194        drop(lock);
 195        callback(new_size, scale_factor);
 196        state_ptr.state.borrow_mut().callbacks.resize = Some(callback);
 197    }
 198    Some(0)
 199}
 200
 201fn handle_size_move_loop(handle: HWND) -> Option<isize> {
 202    unsafe {
 203        let ret = SetTimer(
 204            Some(handle),
 205            SIZE_MOVE_LOOP_TIMER_ID,
 206            USER_TIMER_MINIMUM,
 207            None,
 208        );
 209        if ret == 0 {
 210            log::error!(
 211                "unable to create timer: {}",
 212                std::io::Error::last_os_error()
 213            );
 214        }
 215    }
 216    None
 217}
 218
 219fn handle_size_move_loop_exit(handle: HWND) -> Option<isize> {
 220    unsafe {
 221        KillTimer(Some(handle), SIZE_MOVE_LOOP_TIMER_ID).log_err();
 222    }
 223    None
 224}
 225
 226fn handle_timer_msg(
 227    handle: HWND,
 228    wparam: WPARAM,
 229    state_ptr: Rc<WindowsWindowStatePtr>,
 230) -> Option<isize> {
 231    if wparam.0 == SIZE_MOVE_LOOP_TIMER_ID {
 232        for runnable in state_ptr.main_receiver.drain() {
 233            runnable.run();
 234        }
 235        handle_paint_msg(handle, state_ptr)
 236    } else {
 237        None
 238    }
 239}
 240
 241fn handle_paint_msg(handle: HWND, state_ptr: Rc<WindowsWindowStatePtr>) -> Option<isize> {
 242    draw_window(handle, false, state_ptr)
 243}
 244
 245fn handle_close_msg(state_ptr: Rc<WindowsWindowStatePtr>) -> Option<isize> {
 246    let mut callback = state_ptr.state.borrow_mut().callbacks.should_close.take()?;
 247    let should_close = callback();
 248    state_ptr.state.borrow_mut().callbacks.should_close = Some(callback);
 249    if should_close { None } else { Some(0) }
 250}
 251
 252fn handle_destroy_msg(handle: HWND, state_ptr: Rc<WindowsWindowStatePtr>) -> Option<isize> {
 253    let callback = {
 254        let mut lock = state_ptr.state.borrow_mut();
 255        lock.callbacks.close.take()
 256    };
 257    if let Some(callback) = callback {
 258        callback();
 259    }
 260    unsafe {
 261        PostThreadMessageW(
 262            state_ptr.main_thread_id_win32,
 263            WM_GPUI_CLOSE_ONE_WINDOW,
 264            WPARAM(state_ptr.validation_number),
 265            LPARAM(handle.0 as isize),
 266        )
 267        .log_err();
 268    }
 269    Some(0)
 270}
 271
 272fn handle_mouse_move_msg(
 273    handle: HWND,
 274    lparam: LPARAM,
 275    wparam: WPARAM,
 276    state_ptr: Rc<WindowsWindowStatePtr>,
 277) -> Option<isize> {
 278    start_tracking_mouse(handle, &state_ptr, TME_LEAVE);
 279
 280    let mut lock = state_ptr.state.borrow_mut();
 281    let Some(mut func) = lock.callbacks.input.take() else {
 282        return Some(1);
 283    };
 284    let scale_factor = lock.scale_factor;
 285    drop(lock);
 286
 287    let pressed_button = match MODIFIERKEYS_FLAGS(wparam.loword() as u32) {
 288        flags if flags.contains(MK_LBUTTON) => Some(MouseButton::Left),
 289        flags if flags.contains(MK_RBUTTON) => Some(MouseButton::Right),
 290        flags if flags.contains(MK_MBUTTON) => Some(MouseButton::Middle),
 291        flags if flags.contains(MK_XBUTTON1) => {
 292            Some(MouseButton::Navigate(NavigationDirection::Back))
 293        }
 294        flags if flags.contains(MK_XBUTTON2) => {
 295            Some(MouseButton::Navigate(NavigationDirection::Forward))
 296        }
 297        _ => None,
 298    };
 299    let x = lparam.signed_loword() as f32;
 300    let y = lparam.signed_hiword() as f32;
 301    let input = PlatformInput::MouseMove(MouseMoveEvent {
 302        position: logical_point(x, y, scale_factor),
 303        pressed_button,
 304        modifiers: current_modifiers(),
 305    });
 306    let handled = !func(input).propagate;
 307    state_ptr.state.borrow_mut().callbacks.input = Some(func);
 308
 309    if handled { Some(0) } else { Some(1) }
 310}
 311
 312fn handle_mouse_leave_msg(state_ptr: Rc<WindowsWindowStatePtr>) -> Option<isize> {
 313    let mut lock = state_ptr.state.borrow_mut();
 314    lock.hovered = false;
 315    if let Some(mut callback) = lock.callbacks.hovered_status_change.take() {
 316        drop(lock);
 317        callback(false);
 318        state_ptr.state.borrow_mut().callbacks.hovered_status_change = Some(callback);
 319    }
 320
 321    Some(0)
 322}
 323
 324fn handle_syskeydown_msg(
 325    handle: HWND,
 326    wparam: WPARAM,
 327    lparam: LPARAM,
 328    state_ptr: Rc<WindowsWindowStatePtr>,
 329) -> Option<isize> {
 330    let mut lock = state_ptr.state.borrow_mut();
 331    let input = handle_key_event(handle, wparam, lparam, &mut lock, |keystroke| {
 332        PlatformInput::KeyDown(KeyDownEvent {
 333            keystroke,
 334            is_held: lparam.0 & (0x1 << 30) > 0,
 335        })
 336    })?;
 337    let mut func = lock.callbacks.input.take()?;
 338    drop(lock);
 339
 340    let handled = !func(input).propagate;
 341
 342    let mut lock = state_ptr.state.borrow_mut();
 343    lock.callbacks.input = Some(func);
 344
 345    if handled {
 346        lock.system_key_handled = true;
 347        Some(0)
 348    } else {
 349        // we need to call `DefWindowProcW`, or we will lose the system-wide `Alt+F4`, `Alt+{other keys}`
 350        // shortcuts.
 351        None
 352    }
 353}
 354
 355fn handle_syskeyup_msg(
 356    handle: HWND,
 357    wparam: WPARAM,
 358    lparam: LPARAM,
 359    state_ptr: Rc<WindowsWindowStatePtr>,
 360) -> Option<isize> {
 361    let mut lock = state_ptr.state.borrow_mut();
 362    let input = handle_key_event(handle, wparam, lparam, &mut lock, |keystroke| {
 363        PlatformInput::KeyUp(KeyUpEvent { keystroke })
 364    })?;
 365    let mut func = lock.callbacks.input.take()?;
 366    drop(lock);
 367    func(input);
 368    state_ptr.state.borrow_mut().callbacks.input = Some(func);
 369
 370    // Always return 0 to indicate that the message was handled, so we could properly handle `ModifiersChanged` event.
 371    Some(0)
 372}
 373
 374// It's a known bug that you can't trigger `ctrl-shift-0`. See:
 375// https://superuser.com/questions/1455762/ctrl-shift-number-key-combination-has-stopped-working-for-a-few-numbers
 376fn handle_keydown_msg(
 377    handle: HWND,
 378    wparam: WPARAM,
 379    lparam: LPARAM,
 380    state_ptr: Rc<WindowsWindowStatePtr>,
 381) -> Option<isize> {
 382    let mut lock = state_ptr.state.borrow_mut();
 383    let Some(input) = handle_key_event(handle, wparam, lparam, &mut lock, |keystroke| {
 384        PlatformInput::KeyDown(KeyDownEvent {
 385            keystroke,
 386            is_held: lparam.0 & (0x1 << 30) > 0,
 387        })
 388    }) else {
 389        return Some(1);
 390    };
 391    drop(lock);
 392
 393    let is_composing = with_input_handler(&state_ptr, |input_handler| {
 394        input_handler.marked_text_range()
 395    })
 396    .flatten()
 397    .is_some();
 398    if is_composing {
 399        translate_message(handle, wparam, lparam);
 400        return Some(0);
 401    }
 402
 403    let Some(mut func) = state_ptr.state.borrow_mut().callbacks.input.take() else {
 404        return Some(1);
 405    };
 406
 407    let handled = !func(input).propagate;
 408
 409    state_ptr.state.borrow_mut().callbacks.input = Some(func);
 410
 411    if handled {
 412        Some(0)
 413    } else {
 414        translate_message(handle, wparam, lparam);
 415        Some(1)
 416    }
 417}
 418
 419fn handle_keyup_msg(
 420    handle: HWND,
 421    wparam: WPARAM,
 422    lparam: LPARAM,
 423    state_ptr: Rc<WindowsWindowStatePtr>,
 424) -> Option<isize> {
 425    let mut lock = state_ptr.state.borrow_mut();
 426    let Some(input) = handle_key_event(handle, wparam, lparam, &mut lock, |keystroke| {
 427        PlatformInput::KeyUp(KeyUpEvent { keystroke })
 428    }) else {
 429        return Some(1);
 430    };
 431
 432    let Some(mut func) = lock.callbacks.input.take() else {
 433        return Some(1);
 434    };
 435    drop(lock);
 436
 437    let handled = !func(input).propagate;
 438    state_ptr.state.borrow_mut().callbacks.input = Some(func);
 439
 440    if handled { Some(0) } else { Some(1) }
 441}
 442
 443fn handle_char_msg(wparam: WPARAM, state_ptr: Rc<WindowsWindowStatePtr>) -> Option<isize> {
 444    let input = parse_char_message(wparam, &state_ptr)?;
 445    with_input_handler(&state_ptr, |input_handler| {
 446        input_handler.replace_text_in_range(None, &input);
 447    });
 448
 449    Some(0)
 450}
 451
 452fn handle_dead_char_msg(wparam: WPARAM, state_ptr: Rc<WindowsWindowStatePtr>) -> Option<isize> {
 453    let ch = char::from_u32(wparam.0 as u32)?.to_string();
 454    with_input_handler(&state_ptr, |input_handler| {
 455        input_handler.replace_and_mark_text_in_range(None, &ch, None);
 456    });
 457    None
 458}
 459
 460fn handle_mouse_down_msg(
 461    handle: HWND,
 462    button: MouseButton,
 463    lparam: LPARAM,
 464    state_ptr: Rc<WindowsWindowStatePtr>,
 465) -> Option<isize> {
 466    unsafe { SetCapture(handle) };
 467    let mut lock = state_ptr.state.borrow_mut();
 468    let Some(mut func) = lock.callbacks.input.take() else {
 469        return Some(1);
 470    };
 471    let x = lparam.signed_loword();
 472    let y = lparam.signed_hiword();
 473    let physical_point = point(DevicePixels(x as i32), DevicePixels(y as i32));
 474    let click_count = lock.click_state.update(button, physical_point);
 475    let scale_factor = lock.scale_factor;
 476    drop(lock);
 477
 478    let input = PlatformInput::MouseDown(MouseDownEvent {
 479        button,
 480        position: logical_point(x as f32, y as f32, scale_factor),
 481        modifiers: current_modifiers(),
 482        click_count,
 483        first_mouse: false,
 484    });
 485    let handled = !func(input).propagate;
 486    state_ptr.state.borrow_mut().callbacks.input = Some(func);
 487
 488    if handled { Some(0) } else { Some(1) }
 489}
 490
 491fn handle_mouse_up_msg(
 492    _handle: HWND,
 493    button: MouseButton,
 494    lparam: LPARAM,
 495    state_ptr: Rc<WindowsWindowStatePtr>,
 496) -> Option<isize> {
 497    unsafe { ReleaseCapture().log_err() };
 498    let mut lock = state_ptr.state.borrow_mut();
 499    let Some(mut func) = lock.callbacks.input.take() else {
 500        return Some(1);
 501    };
 502    let x = lparam.signed_loword() as f32;
 503    let y = lparam.signed_hiword() as f32;
 504    let click_count = lock.click_state.current_count;
 505    let scale_factor = lock.scale_factor;
 506    drop(lock);
 507
 508    let input = PlatformInput::MouseUp(MouseUpEvent {
 509        button,
 510        position: logical_point(x, y, scale_factor),
 511        modifiers: current_modifiers(),
 512        click_count,
 513    });
 514    let handled = !func(input).propagate;
 515    state_ptr.state.borrow_mut().callbacks.input = Some(func);
 516
 517    if handled { Some(0) } else { Some(1) }
 518}
 519
 520fn handle_xbutton_msg(
 521    handle: HWND,
 522    wparam: WPARAM,
 523    lparam: LPARAM,
 524    handler: impl Fn(HWND, MouseButton, LPARAM, Rc<WindowsWindowStatePtr>) -> Option<isize>,
 525    state_ptr: Rc<WindowsWindowStatePtr>,
 526) -> Option<isize> {
 527    let nav_dir = match wparam.hiword() {
 528        XBUTTON1 => NavigationDirection::Back,
 529        XBUTTON2 => NavigationDirection::Forward,
 530        _ => return Some(1),
 531    };
 532    handler(handle, MouseButton::Navigate(nav_dir), lparam, state_ptr)
 533}
 534
 535fn handle_mouse_wheel_msg(
 536    handle: HWND,
 537    wparam: WPARAM,
 538    lparam: LPARAM,
 539    state_ptr: Rc<WindowsWindowStatePtr>,
 540) -> Option<isize> {
 541    let modifiers = current_modifiers();
 542    let mut lock = state_ptr.state.borrow_mut();
 543    let Some(mut func) = lock.callbacks.input.take() else {
 544        return Some(1);
 545    };
 546    let scale_factor = lock.scale_factor;
 547    let wheel_scroll_amount = match modifiers.shift {
 548        true => lock.system_settings.mouse_wheel_settings.wheel_scroll_chars,
 549        false => lock.system_settings.mouse_wheel_settings.wheel_scroll_lines,
 550    };
 551    drop(lock);
 552
 553    let wheel_distance =
 554        (wparam.signed_hiword() as f32 / WHEEL_DELTA as f32) * wheel_scroll_amount as f32;
 555    let mut cursor_point = POINT {
 556        x: lparam.signed_loword().into(),
 557        y: lparam.signed_hiword().into(),
 558    };
 559    unsafe { ScreenToClient(handle, &mut cursor_point).ok().log_err() };
 560    let input = PlatformInput::ScrollWheel(ScrollWheelEvent {
 561        position: logical_point(cursor_point.x as f32, cursor_point.y as f32, scale_factor),
 562        delta: ScrollDelta::Lines(match modifiers.shift {
 563            true => Point {
 564                x: wheel_distance,
 565                y: 0.0,
 566            },
 567            false => Point {
 568                y: wheel_distance,
 569                x: 0.0,
 570            },
 571        }),
 572        modifiers,
 573        touch_phase: TouchPhase::Moved,
 574    });
 575    let handled = !func(input).propagate;
 576    state_ptr.state.borrow_mut().callbacks.input = Some(func);
 577
 578    if handled { Some(0) } else { Some(1) }
 579}
 580
 581fn handle_mouse_horizontal_wheel_msg(
 582    handle: HWND,
 583    wparam: WPARAM,
 584    lparam: LPARAM,
 585    state_ptr: Rc<WindowsWindowStatePtr>,
 586) -> Option<isize> {
 587    let mut lock = state_ptr.state.borrow_mut();
 588    let Some(mut func) = lock.callbacks.input.take() else {
 589        return Some(1);
 590    };
 591    let scale_factor = lock.scale_factor;
 592    let wheel_scroll_chars = lock.system_settings.mouse_wheel_settings.wheel_scroll_chars;
 593    drop(lock);
 594
 595    let wheel_distance =
 596        (-wparam.signed_hiword() as f32 / WHEEL_DELTA as f32) * wheel_scroll_chars as f32;
 597    let mut cursor_point = POINT {
 598        x: lparam.signed_loword().into(),
 599        y: lparam.signed_hiword().into(),
 600    };
 601    unsafe { ScreenToClient(handle, &mut cursor_point).ok().log_err() };
 602    let event = PlatformInput::ScrollWheel(ScrollWheelEvent {
 603        position: logical_point(cursor_point.x as f32, cursor_point.y as f32, scale_factor),
 604        delta: ScrollDelta::Lines(Point {
 605            x: wheel_distance,
 606            y: 0.0,
 607        }),
 608        modifiers: current_modifiers(),
 609        touch_phase: TouchPhase::Moved,
 610    });
 611    let handled = !func(event).propagate;
 612    state_ptr.state.borrow_mut().callbacks.input = Some(func);
 613
 614    if handled { Some(0) } else { Some(1) }
 615}
 616
 617fn retrieve_caret_position(state_ptr: &Rc<WindowsWindowStatePtr>) -> Option<POINT> {
 618    with_input_handler_and_scale_factor(state_ptr, |input_handler, scale_factor| {
 619        let caret_range = input_handler.selected_text_range(false)?;
 620        let caret_position = input_handler.bounds_for_range(caret_range.range)?;
 621        Some(POINT {
 622            // logical to physical
 623            x: (caret_position.origin.x.0 * scale_factor) as i32,
 624            y: (caret_position.origin.y.0 * scale_factor) as i32
 625                + ((caret_position.size.height.0 * scale_factor) as i32 / 2),
 626        })
 627    })
 628}
 629
 630fn handle_ime_position(handle: HWND, state_ptr: Rc<WindowsWindowStatePtr>) -> Option<isize> {
 631    unsafe {
 632        let ctx = ImmGetContext(handle);
 633
 634        let Some(caret_position) = retrieve_caret_position(&state_ptr) else {
 635            return Some(0);
 636        };
 637        {
 638            let config = COMPOSITIONFORM {
 639                dwStyle: CFS_POINT,
 640                ptCurrentPos: caret_position,
 641                ..Default::default()
 642            };
 643            ImmSetCompositionWindow(ctx, &config as _).ok().log_err();
 644        }
 645        {
 646            let config = CANDIDATEFORM {
 647                dwStyle: CFS_CANDIDATEPOS,
 648                ptCurrentPos: caret_position,
 649                ..Default::default()
 650            };
 651            ImmSetCandidateWindow(ctx, &config as _).ok().log_err();
 652        }
 653        ImmReleaseContext(handle, ctx).ok().log_err();
 654        Some(0)
 655    }
 656}
 657
 658fn handle_ime_composition(
 659    handle: HWND,
 660    lparam: LPARAM,
 661    state_ptr: Rc<WindowsWindowStatePtr>,
 662) -> Option<isize> {
 663    let ctx = unsafe { ImmGetContext(handle) };
 664    let result = handle_ime_composition_inner(ctx, lparam, state_ptr);
 665    unsafe { ImmReleaseContext(handle, ctx).ok().log_err() };
 666    result
 667}
 668
 669fn handle_ime_composition_inner(
 670    ctx: HIMC,
 671    lparam: LPARAM,
 672    state_ptr: Rc<WindowsWindowStatePtr>,
 673) -> Option<isize> {
 674    let lparam = lparam.0 as u32;
 675    if lparam == 0 {
 676        // Japanese IME may send this message with lparam = 0, which indicates that
 677        // there is no composition string.
 678        with_input_handler(&state_ptr, |input_handler| {
 679            input_handler.replace_text_in_range(None, "");
 680        })?;
 681        Some(0)
 682    } else {
 683        if lparam & GCS_COMPSTR.0 > 0 {
 684            let comp_string = parse_ime_composition_string(ctx, GCS_COMPSTR)?;
 685            let caret_pos = (!comp_string.is_empty() && lparam & GCS_CURSORPOS.0 > 0).then(|| {
 686                let pos = retrieve_composition_cursor_position(ctx);
 687                pos..pos
 688            });
 689            with_input_handler(&state_ptr, |input_handler| {
 690                input_handler.replace_and_mark_text_in_range(None, &comp_string, caret_pos);
 691            })?;
 692        }
 693        if lparam & GCS_RESULTSTR.0 > 0 {
 694            let comp_result = parse_ime_composition_string(ctx, GCS_RESULTSTR)?;
 695            with_input_handler(&state_ptr, |input_handler| {
 696                input_handler.replace_text_in_range(None, &comp_result);
 697            })?;
 698            return Some(0);
 699        }
 700
 701        // currently, we don't care other stuff
 702        None
 703    }
 704}
 705
 706/// SEE: https://learn.microsoft.com/en-us/windows/win32/winmsg/wm-nccalcsize
 707fn handle_calc_client_size(
 708    handle: HWND,
 709    wparam: WPARAM,
 710    lparam: LPARAM,
 711    state_ptr: Rc<WindowsWindowStatePtr>,
 712) -> Option<isize> {
 713    if !state_ptr.hide_title_bar || state_ptr.state.borrow().is_fullscreen() || wparam.0 == 0 {
 714        return None;
 715    }
 716
 717    let is_maximized = state_ptr.state.borrow().is_maximized();
 718    let insets = get_client_area_insets(handle, is_maximized, state_ptr.windows_version);
 719    // wparam is TRUE so lparam points to an NCCALCSIZE_PARAMS structure
 720    let mut params = lparam.0 as *mut NCCALCSIZE_PARAMS;
 721    let mut requested_client_rect = unsafe { &mut ((*params).rgrc) };
 722
 723    requested_client_rect[0].left += insets.left;
 724    requested_client_rect[0].top += insets.top;
 725    requested_client_rect[0].right -= insets.right;
 726    requested_client_rect[0].bottom -= insets.bottom;
 727
 728    // Fix auto hide taskbar not showing. This solution is based on the approach
 729    // used by Chrome. However, it may result in one row of pixels being obscured
 730    // in our client area. But as Chrome says, "there seems to be no better solution."
 731    if is_maximized {
 732        if let Some(ref taskbar_position) = state_ptr
 733            .state
 734            .borrow()
 735            .system_settings
 736            .auto_hide_taskbar_position
 737        {
 738            // Fot the auto-hide taskbar, adjust in by 1 pixel on taskbar edge,
 739            // so the window isn't treated as a "fullscreen app", which would cause
 740            // the taskbar to disappear.
 741            match taskbar_position {
 742                AutoHideTaskbarPosition::Left => {
 743                    requested_client_rect[0].left += AUTO_HIDE_TASKBAR_THICKNESS_PX
 744                }
 745                AutoHideTaskbarPosition::Top => {
 746                    requested_client_rect[0].top += AUTO_HIDE_TASKBAR_THICKNESS_PX
 747                }
 748                AutoHideTaskbarPosition::Right => {
 749                    requested_client_rect[0].right -= AUTO_HIDE_TASKBAR_THICKNESS_PX
 750                }
 751                AutoHideTaskbarPosition::Bottom => {
 752                    requested_client_rect[0].bottom -= AUTO_HIDE_TASKBAR_THICKNESS_PX
 753                }
 754            }
 755        }
 756    }
 757
 758    Some(0)
 759}
 760
 761fn handle_activate_msg(wparam: WPARAM, state_ptr: Rc<WindowsWindowStatePtr>) -> Option<isize> {
 762    let activated = wparam.loword() > 0;
 763    let this = state_ptr.clone();
 764    state_ptr
 765        .executor
 766        .spawn(async move {
 767            let mut lock = this.state.borrow_mut();
 768            if let Some(mut func) = lock.callbacks.active_status_change.take() {
 769                drop(lock);
 770                func(activated);
 771                this.state.borrow_mut().callbacks.active_status_change = Some(func);
 772            }
 773        })
 774        .detach();
 775
 776    None
 777}
 778
 779fn handle_create_msg(handle: HWND, state_ptr: Rc<WindowsWindowStatePtr>) -> Option<isize> {
 780    if state_ptr.hide_title_bar {
 781        notify_frame_changed(handle);
 782        Some(0)
 783    } else {
 784        None
 785    }
 786}
 787
 788fn handle_dpi_changed_msg(
 789    handle: HWND,
 790    wparam: WPARAM,
 791    lparam: LPARAM,
 792    state_ptr: Rc<WindowsWindowStatePtr>,
 793) -> Option<isize> {
 794    let new_dpi = wparam.loword() as f32;
 795    let mut lock = state_ptr.state.borrow_mut();
 796    lock.scale_factor = new_dpi / USER_DEFAULT_SCREEN_DPI as f32;
 797    lock.border_offset.update(handle).log_err();
 798    drop(lock);
 799
 800    let rect = unsafe { &*(lparam.0 as *const RECT) };
 801    let width = rect.right - rect.left;
 802    let height = rect.bottom - rect.top;
 803    // this will emit `WM_SIZE` and `WM_MOVE` right here
 804    // even before this function returns
 805    // the new size is handled in `WM_SIZE`
 806    unsafe {
 807        SetWindowPos(
 808            handle,
 809            None,
 810            rect.left,
 811            rect.top,
 812            width,
 813            height,
 814            SWP_NOZORDER | SWP_NOACTIVATE,
 815        )
 816        .context("unable to set window position after dpi has changed")
 817        .log_err();
 818    }
 819
 820    Some(0)
 821}
 822
 823/// The following conditions will trigger this event:
 824/// 1. The monitor on which the window is located goes offline or changes resolution.
 825/// 2. Another monitor goes offline, is plugged in, or changes resolution.
 826///
 827/// In either case, the window will only receive information from the monitor on which
 828/// it is located.
 829///
 830/// For example, in the case of condition 2, where the monitor on which the window is
 831/// located has actually changed nothing, it will still receive this event.
 832fn handle_display_change_msg(handle: HWND, state_ptr: Rc<WindowsWindowStatePtr>) -> Option<isize> {
 833    // NOTE:
 834    // Even the `lParam` holds the resolution of the screen, we just ignore it.
 835    // Because WM_DPICHANGED, WM_MOVE, WM_SIZE will come first, window reposition and resize
 836    // are handled there.
 837    // So we only care about if monitor is disconnected.
 838    let previous_monitor = state_ptr.state.borrow().display;
 839    if WindowsDisplay::is_connected(previous_monitor.handle) {
 840        // we are fine, other display changed
 841        return None;
 842    }
 843    // display disconnected
 844    // in this case, the OS will move our window to another monitor, and minimize it.
 845    // we deminimize the window and query the monitor after moving
 846    unsafe {
 847        let _ = ShowWindow(handle, SW_SHOWNORMAL);
 848    };
 849    let new_monitor = unsafe { MonitorFromWindow(handle, MONITOR_DEFAULTTONULL) };
 850    // all monitors disconnected
 851    if new_monitor.is_invalid() {
 852        log::error!("No monitor detected!");
 853        return None;
 854    }
 855    let new_display = WindowsDisplay::new_with_handle(new_monitor);
 856    state_ptr.state.borrow_mut().display = new_display;
 857    Some(0)
 858}
 859
 860fn handle_hit_test_msg(
 861    handle: HWND,
 862    msg: u32,
 863    wparam: WPARAM,
 864    lparam: LPARAM,
 865    state_ptr: Rc<WindowsWindowStatePtr>,
 866) -> Option<isize> {
 867    if !state_ptr.is_movable || state_ptr.state.borrow().is_fullscreen() {
 868        return None;
 869    }
 870
 871    let mut lock = state_ptr.state.borrow_mut();
 872    if let Some(mut callback) = lock.callbacks.hit_test_window_control.take() {
 873        drop(lock);
 874        let area = callback();
 875        state_ptr
 876            .state
 877            .borrow_mut()
 878            .callbacks
 879            .hit_test_window_control = Some(callback);
 880        if let Some(area) = area {
 881            return match area {
 882                WindowControlArea::Drag => Some(HTCAPTION as _),
 883                WindowControlArea::Close => Some(HTCLOSE as _),
 884                WindowControlArea::Max => Some(HTMAXBUTTON as _),
 885                WindowControlArea::Min => Some(HTMINBUTTON as _),
 886            };
 887        }
 888    } else {
 889        drop(lock);
 890    }
 891
 892    if !state_ptr.hide_title_bar {
 893        // If the OS draws the title bar, we don't need to handle hit test messages.
 894        return None;
 895    }
 896
 897    // default handler for resize areas
 898    let hit = unsafe { DefWindowProcW(handle, msg, wparam, lparam) };
 899    if matches!(
 900        hit.0 as u32,
 901        HTNOWHERE
 902            | HTRIGHT
 903            | HTLEFT
 904            | HTTOPLEFT
 905            | HTTOP
 906            | HTTOPRIGHT
 907            | HTBOTTOMRIGHT
 908            | HTBOTTOM
 909            | HTBOTTOMLEFT
 910    ) {
 911        return Some(hit.0);
 912    }
 913
 914    if state_ptr.state.borrow().is_fullscreen() {
 915        return Some(HTCLIENT as _);
 916    }
 917
 918    let dpi = unsafe { GetDpiForWindow(handle) };
 919    let frame_y = unsafe { GetSystemMetricsForDpi(SM_CYFRAME, dpi) };
 920
 921    let mut cursor_point = POINT {
 922        x: lparam.signed_loword().into(),
 923        y: lparam.signed_hiword().into(),
 924    };
 925    unsafe { ScreenToClient(handle, &mut cursor_point).ok().log_err() };
 926    if !state_ptr.state.borrow().is_maximized() && cursor_point.y >= 0 && cursor_point.y <= frame_y
 927    {
 928        return Some(HTTOP as _);
 929    }
 930
 931    Some(HTCLIENT as _)
 932}
 933
 934fn handle_nc_mouse_move_msg(
 935    handle: HWND,
 936    lparam: LPARAM,
 937    state_ptr: Rc<WindowsWindowStatePtr>,
 938) -> Option<isize> {
 939    start_tracking_mouse(handle, &state_ptr, TME_LEAVE | TME_NONCLIENT);
 940
 941    let mut lock = state_ptr.state.borrow_mut();
 942    let mut func = lock.callbacks.input.take()?;
 943    let scale_factor = lock.scale_factor;
 944    drop(lock);
 945
 946    let mut cursor_point = POINT {
 947        x: lparam.signed_loword().into(),
 948        y: lparam.signed_hiword().into(),
 949    };
 950    unsafe { ScreenToClient(handle, &mut cursor_point).ok().log_err() };
 951    let input = PlatformInput::MouseMove(MouseMoveEvent {
 952        position: logical_point(cursor_point.x as f32, cursor_point.y as f32, scale_factor),
 953        pressed_button: None,
 954        modifiers: current_modifiers(),
 955    });
 956    let handled = !func(input).propagate;
 957    state_ptr.state.borrow_mut().callbacks.input = Some(func);
 958
 959    if handled { Some(0) } else { None }
 960}
 961
 962fn handle_nc_mouse_down_msg(
 963    handle: HWND,
 964    button: MouseButton,
 965    wparam: WPARAM,
 966    lparam: LPARAM,
 967    state_ptr: Rc<WindowsWindowStatePtr>,
 968) -> Option<isize> {
 969    let mut lock = state_ptr.state.borrow_mut();
 970    if let Some(mut func) = lock.callbacks.input.take() {
 971        let scale_factor = lock.scale_factor;
 972        let mut cursor_point = POINT {
 973            x: lparam.signed_loword().into(),
 974            y: lparam.signed_hiword().into(),
 975        };
 976        unsafe { ScreenToClient(handle, &mut cursor_point).ok().log_err() };
 977        let physical_point = point(DevicePixels(cursor_point.x), DevicePixels(cursor_point.y));
 978        let click_count = lock.click_state.update(button, physical_point);
 979        drop(lock);
 980
 981        let input = PlatformInput::MouseDown(MouseDownEvent {
 982            button,
 983            position: logical_point(cursor_point.x as f32, cursor_point.y as f32, scale_factor),
 984            modifiers: current_modifiers(),
 985            click_count,
 986            first_mouse: false,
 987        });
 988        let result = func(input.clone());
 989        let handled = !result.propagate || result.default_prevented;
 990        state_ptr.state.borrow_mut().callbacks.input = Some(func);
 991
 992        if handled {
 993            return Some(0);
 994        }
 995    } else {
 996        drop(lock);
 997    };
 998
 999    // Since these are handled in handle_nc_mouse_up_msg we must prevent the default window proc
1000    if button == MouseButton::Left {
1001        match wparam.0 as u32 {
1002            HTMINBUTTON => state_ptr.state.borrow_mut().nc_button_pressed = Some(HTMINBUTTON),
1003            HTMAXBUTTON => state_ptr.state.borrow_mut().nc_button_pressed = Some(HTMAXBUTTON),
1004            HTCLOSE => state_ptr.state.borrow_mut().nc_button_pressed = Some(HTCLOSE),
1005            _ => return None,
1006        };
1007        Some(0)
1008    } else {
1009        None
1010    }
1011}
1012
1013fn handle_nc_mouse_up_msg(
1014    handle: HWND,
1015    button: MouseButton,
1016    wparam: WPARAM,
1017    lparam: LPARAM,
1018    state_ptr: Rc<WindowsWindowStatePtr>,
1019) -> Option<isize> {
1020    let mut lock = state_ptr.state.borrow_mut();
1021    if let Some(mut func) = lock.callbacks.input.take() {
1022        let scale_factor = lock.scale_factor;
1023        drop(lock);
1024
1025        let mut cursor_point = POINT {
1026            x: lparam.signed_loword().into(),
1027            y: lparam.signed_hiword().into(),
1028        };
1029        unsafe { ScreenToClient(handle, &mut cursor_point).ok().log_err() };
1030        let input = PlatformInput::MouseUp(MouseUpEvent {
1031            button,
1032            position: logical_point(cursor_point.x as f32, cursor_point.y as f32, scale_factor),
1033            modifiers: current_modifiers(),
1034            click_count: 1,
1035        });
1036        let handled = !func(input).propagate;
1037        state_ptr.state.borrow_mut().callbacks.input = Some(func);
1038
1039        if handled {
1040            return Some(0);
1041        }
1042    } else {
1043        drop(lock);
1044    }
1045
1046    let last_pressed = state_ptr.state.borrow_mut().nc_button_pressed.take();
1047    if button == MouseButton::Left
1048        && let Some(last_pressed) = last_pressed
1049    {
1050        let handled = match (wparam.0 as u32, last_pressed) {
1051            (HTMINBUTTON, HTMINBUTTON) => {
1052                unsafe { ShowWindowAsync(handle, SW_MINIMIZE).ok().log_err() };
1053                true
1054            }
1055            (HTMAXBUTTON, HTMAXBUTTON) => {
1056                if state_ptr.state.borrow().is_maximized() {
1057                    unsafe { ShowWindowAsync(handle, SW_NORMAL).ok().log_err() };
1058                } else {
1059                    unsafe { ShowWindowAsync(handle, SW_MAXIMIZE).ok().log_err() };
1060                }
1061                true
1062            }
1063            (HTCLOSE, HTCLOSE) => {
1064                unsafe {
1065                    PostMessageW(Some(handle), WM_CLOSE, WPARAM::default(), LPARAM::default())
1066                        .log_err()
1067                };
1068                true
1069            }
1070            _ => false,
1071        };
1072        if handled {
1073            return Some(0);
1074        }
1075    }
1076
1077    None
1078}
1079
1080fn handle_cursor_changed(lparam: LPARAM, state_ptr: Rc<WindowsWindowStatePtr>) -> Option<isize> {
1081    let mut state = state_ptr.state.borrow_mut();
1082    let had_cursor = state.current_cursor.is_some();
1083
1084    state.current_cursor = if lparam.0 == 0 {
1085        None
1086    } else {
1087        Some(HCURSOR(lparam.0 as _))
1088    };
1089
1090    if had_cursor != state.current_cursor.is_some() {
1091        unsafe { SetCursor(state.current_cursor) };
1092    }
1093
1094    Some(0)
1095}
1096
1097fn handle_set_cursor(
1098    handle: HWND,
1099    lparam: LPARAM,
1100    state_ptr: Rc<WindowsWindowStatePtr>,
1101) -> Option<isize> {
1102    if unsafe { !IsWindowEnabled(handle).as_bool() }
1103        || matches!(
1104            lparam.loword() as u32,
1105            HTLEFT
1106                | HTRIGHT
1107                | HTTOP
1108                | HTTOPLEFT
1109                | HTTOPRIGHT
1110                | HTBOTTOM
1111                | HTBOTTOMLEFT
1112                | HTBOTTOMRIGHT
1113        )
1114    {
1115        return None;
1116    }
1117    unsafe {
1118        SetCursor(state_ptr.state.borrow().current_cursor);
1119    };
1120    Some(1)
1121}
1122
1123fn handle_system_settings_changed(
1124    handle: HWND,
1125    wparam: WPARAM,
1126    lparam: LPARAM,
1127    state_ptr: Rc<WindowsWindowStatePtr>,
1128) -> Option<isize> {
1129    if wparam.0 != 0 {
1130        let mut lock = state_ptr.state.borrow_mut();
1131        let display = lock.display;
1132        lock.system_settings.update(display, wparam.0);
1133        lock.click_state.system_update(wparam.0);
1134        lock.border_offset.update(handle).log_err();
1135    } else {
1136        handle_system_theme_changed(handle, lparam, state_ptr)?;
1137    };
1138    // Force to trigger WM_NCCALCSIZE event to ensure that we handle auto hide
1139    // taskbar correctly.
1140    notify_frame_changed(handle);
1141
1142    Some(0)
1143}
1144
1145fn handle_system_command(wparam: WPARAM, state_ptr: Rc<WindowsWindowStatePtr>) -> Option<isize> {
1146    if wparam.0 == SC_KEYMENU as usize {
1147        let mut lock = state_ptr.state.borrow_mut();
1148        if lock.system_key_handled {
1149            lock.system_key_handled = false;
1150            return Some(0);
1151        }
1152    }
1153    None
1154}
1155
1156fn handle_system_theme_changed(
1157    handle: HWND,
1158    lparam: LPARAM,
1159    state_ptr: Rc<WindowsWindowStatePtr>,
1160) -> Option<isize> {
1161    // lParam is a pointer to a string that indicates the area containing the system parameter
1162    // that was changed.
1163    let parameter = PCWSTR::from_raw(lparam.0 as _);
1164    if unsafe { !parameter.is_null() && !parameter.is_empty() } {
1165        if let Some(parameter_string) = unsafe { parameter.to_string() }.log_err() {
1166            log::info!("System settings changed: {}", parameter_string);
1167            match parameter_string.as_str() {
1168                "ImmersiveColorSet" => {
1169                    let new_appearance = system_appearance()
1170                        .context("unable to get system appearance when handling ImmersiveColorSet")
1171                        .log_err()?;
1172                    let mut lock = state_ptr.state.borrow_mut();
1173                    if new_appearance != lock.appearance {
1174                        lock.appearance = new_appearance;
1175                        let mut callback = lock.callbacks.appearance_changed.take()?;
1176                        drop(lock);
1177                        callback();
1178                        state_ptr.state.borrow_mut().callbacks.appearance_changed = Some(callback);
1179                        configure_dwm_dark_mode(handle, new_appearance);
1180                    }
1181                }
1182                _ => {}
1183            }
1184        }
1185    }
1186    Some(0)
1187}
1188
1189fn handle_input_language_changed(
1190    lparam: LPARAM,
1191    state_ptr: Rc<WindowsWindowStatePtr>,
1192) -> Option<isize> {
1193    let thread = state_ptr.main_thread_id_win32;
1194    let validation = state_ptr.validation_number;
1195    unsafe {
1196        PostThreadMessageW(thread, WM_INPUTLANGCHANGE, WPARAM(validation), lparam).log_err();
1197    }
1198    Some(0)
1199}
1200
1201fn handle_device_change_msg(
1202    handle: HWND,
1203    wparam: WPARAM,
1204    state_ptr: Rc<WindowsWindowStatePtr>,
1205) -> Option<isize> {
1206    if wparam.0 == DBT_DEVNODES_CHANGED as usize {
1207        // The reason for sending this message is to actually trigger a redraw of the window.
1208        unsafe {
1209            PostMessageW(
1210                Some(handle),
1211                WM_GPUI_FORCE_UPDATE_WINDOW,
1212                WPARAM(0),
1213                LPARAM(0),
1214            )
1215            .log_err();
1216        }
1217        // If the GPU device is lost, this redraw will take care of recreating the device context.
1218        // The WM_GPUI_FORCE_UPDATE_WINDOW message will take care of redrawing the window, after
1219        // the device context has been recreated.
1220        draw_window(handle, true, state_ptr)
1221    } else {
1222        // Other device change messages are not handled.
1223        None
1224    }
1225}
1226
1227#[inline]
1228fn draw_window(
1229    handle: HWND,
1230    force_render: bool,
1231    state_ptr: Rc<WindowsWindowStatePtr>,
1232) -> Option<isize> {
1233    let mut request_frame = state_ptr
1234        .state
1235        .borrow_mut()
1236        .callbacks
1237        .request_frame
1238        .take()?;
1239    request_frame(RequestFrameOptions {
1240        require_presentation: false,
1241        force_render,
1242    });
1243    state_ptr.state.borrow_mut().callbacks.request_frame = Some(request_frame);
1244    unsafe { ValidateRect(Some(handle), None).ok().log_err() };
1245    Some(0)
1246}
1247
1248#[inline]
1249fn parse_char_message(wparam: WPARAM, state_ptr: &Rc<WindowsWindowStatePtr>) -> Option<String> {
1250    let code_point = wparam.loword();
1251    let mut lock = state_ptr.state.borrow_mut();
1252    // https://www.unicode.org/versions/Unicode16.0.0/core-spec/chapter-3/#G2630
1253    match code_point {
1254        0xD800..=0xDBFF => {
1255            // High surrogate, wait for low surrogate
1256            lock.pending_surrogate = Some(code_point);
1257            None
1258        }
1259        0xDC00..=0xDFFF => {
1260            if let Some(high_surrogate) = lock.pending_surrogate.take() {
1261                // Low surrogate, combine with pending high surrogate
1262                String::from_utf16(&[high_surrogate, code_point]).ok()
1263            } else {
1264                // Invalid low surrogate without a preceding high surrogate
1265                log::warn!(
1266                    "Received low surrogate without a preceding high surrogate: {code_point:x}"
1267                );
1268                None
1269            }
1270        }
1271        _ => {
1272            lock.pending_surrogate = None;
1273            char::from_u32(code_point as u32)
1274                .filter(|c| !c.is_control())
1275                .map(|c| c.to_string())
1276        }
1277    }
1278}
1279
1280#[inline]
1281fn translate_message(handle: HWND, wparam: WPARAM, lparam: LPARAM) {
1282    let msg = MSG {
1283        hwnd: handle,
1284        message: WM_KEYDOWN,
1285        wParam: wparam,
1286        lParam: lparam,
1287        // It seems like leaving the following two parameters empty doesn't break key events, they still work as expected.
1288        // But if any bugs pop up after this PR, this is probably the place to look first.
1289        time: 0,
1290        pt: POINT::default(),
1291    };
1292    unsafe { TranslateMessage(&msg).ok().log_err() };
1293}
1294
1295fn handle_key_event<F>(
1296    handle: HWND,
1297    wparam: WPARAM,
1298    lparam: LPARAM,
1299    state: &mut WindowsWindowState,
1300    f: F,
1301) -> Option<PlatformInput>
1302where
1303    F: FnOnce(Keystroke) -> PlatformInput,
1304{
1305    let virtual_key = VIRTUAL_KEY(wparam.loword());
1306    let mut modifiers = current_modifiers();
1307
1308    match virtual_key {
1309        VK_SHIFT | VK_CONTROL | VK_MENU | VK_LWIN | VK_RWIN => {
1310            if state
1311                .last_reported_modifiers
1312                .is_some_and(|prev_modifiers| prev_modifiers == modifiers)
1313            {
1314                return None;
1315            }
1316            state.last_reported_modifiers = Some(modifiers);
1317            Some(PlatformInput::ModifiersChanged(ModifiersChangedEvent {
1318                modifiers,
1319                capslock: current_capslock(),
1320            }))
1321        }
1322        VK_PACKET => {
1323            translate_message(handle, wparam, lparam);
1324            None
1325        }
1326        VK_CAPITAL => {
1327            let capslock = current_capslock();
1328            if state
1329                .last_reported_capslock
1330                .is_some_and(|prev_capslock| prev_capslock == capslock)
1331            {
1332                return None;
1333            }
1334            state.last_reported_capslock = Some(capslock);
1335            Some(PlatformInput::ModifiersChanged(ModifiersChangedEvent {
1336                modifiers,
1337                capslock,
1338            }))
1339        }
1340        vkey => {
1341            let vkey = if vkey == VK_PROCESSKEY {
1342                VIRTUAL_KEY(unsafe { ImmGetVirtualKey(handle) } as u16)
1343            } else {
1344                vkey
1345            };
1346            let keystroke = parse_normal_key(vkey, lparam, modifiers)?;
1347            Some(f(keystroke))
1348        }
1349    }
1350}
1351
1352fn parse_immutable(vkey: VIRTUAL_KEY) -> Option<String> {
1353    Some(
1354        match vkey {
1355            VK_SPACE => "space",
1356            VK_BACK => "backspace",
1357            VK_RETURN => "enter",
1358            VK_TAB => "tab",
1359            VK_UP => "up",
1360            VK_DOWN => "down",
1361            VK_RIGHT => "right",
1362            VK_LEFT => "left",
1363            VK_HOME => "home",
1364            VK_END => "end",
1365            VK_PRIOR => "pageup",
1366            VK_NEXT => "pagedown",
1367            VK_BROWSER_BACK => "back",
1368            VK_BROWSER_FORWARD => "forward",
1369            VK_ESCAPE => "escape",
1370            VK_INSERT => "insert",
1371            VK_DELETE => "delete",
1372            VK_APPS => "menu",
1373            VK_F1 => "f1",
1374            VK_F2 => "f2",
1375            VK_F3 => "f3",
1376            VK_F4 => "f4",
1377            VK_F5 => "f5",
1378            VK_F6 => "f6",
1379            VK_F7 => "f7",
1380            VK_F8 => "f8",
1381            VK_F9 => "f9",
1382            VK_F10 => "f10",
1383            VK_F11 => "f11",
1384            VK_F12 => "f12",
1385            VK_F13 => "f13",
1386            VK_F14 => "f14",
1387            VK_F15 => "f15",
1388            VK_F16 => "f16",
1389            VK_F17 => "f17",
1390            VK_F18 => "f18",
1391            VK_F19 => "f19",
1392            VK_F20 => "f20",
1393            VK_F21 => "f21",
1394            VK_F22 => "f22",
1395            VK_F23 => "f23",
1396            VK_F24 => "f24",
1397            _ => return None,
1398        }
1399        .to_string(),
1400    )
1401}
1402
1403fn parse_normal_key(
1404    vkey: VIRTUAL_KEY,
1405    lparam: LPARAM,
1406    mut modifiers: Modifiers,
1407) -> Option<Keystroke> {
1408    let mut key_char = None;
1409    let key = parse_immutable(vkey).or_else(|| {
1410        let scan_code = lparam.hiword() & 0xFF;
1411        key_char = generate_key_char(
1412            vkey,
1413            scan_code as u32,
1414            modifiers.control,
1415            modifiers.shift,
1416            modifiers.alt,
1417        );
1418        get_keystroke_key(vkey, scan_code as u32, &mut modifiers)
1419    })?;
1420    Some(Keystroke {
1421        modifiers,
1422        key,
1423        key_char,
1424    })
1425}
1426
1427fn parse_ime_composition_string(ctx: HIMC, comp_type: IME_COMPOSITION_STRING) -> Option<String> {
1428    unsafe {
1429        let string_len = ImmGetCompositionStringW(ctx, comp_type, None, 0);
1430        if string_len >= 0 {
1431            let mut buffer = vec![0u8; string_len as usize + 2];
1432            ImmGetCompositionStringW(
1433                ctx,
1434                comp_type,
1435                Some(buffer.as_mut_ptr() as _),
1436                string_len as _,
1437            );
1438            let wstring = std::slice::from_raw_parts::<u16>(
1439                buffer.as_mut_ptr().cast::<u16>(),
1440                string_len as usize / 2,
1441            );
1442            Some(String::from_utf16_lossy(wstring))
1443        } else {
1444            None
1445        }
1446    }
1447}
1448
1449#[inline]
1450fn retrieve_composition_cursor_position(ctx: HIMC) -> usize {
1451    unsafe { ImmGetCompositionStringW(ctx, GCS_CURSORPOS, None, 0) as usize }
1452}
1453
1454#[inline]
1455fn is_virtual_key_pressed(vkey: VIRTUAL_KEY) -> bool {
1456    unsafe { GetKeyState(vkey.0 as i32) < 0 }
1457}
1458
1459#[inline]
1460pub(crate) fn current_modifiers() -> Modifiers {
1461    Modifiers {
1462        control: is_virtual_key_pressed(VK_CONTROL),
1463        alt: is_virtual_key_pressed(VK_MENU),
1464        shift: is_virtual_key_pressed(VK_SHIFT),
1465        platform: is_virtual_key_pressed(VK_LWIN) || is_virtual_key_pressed(VK_RWIN),
1466        function: false,
1467    }
1468}
1469
1470#[inline]
1471pub(crate) fn current_capslock() -> Capslock {
1472    let on = unsafe { GetKeyState(VK_CAPITAL.0 as i32) & 1 } > 0;
1473    Capslock { on: on }
1474}
1475
1476fn get_client_area_insets(
1477    handle: HWND,
1478    is_maximized: bool,
1479    windows_version: WindowsVersion,
1480) -> RECT {
1481    // For maximized windows, Windows outdents the window rect from the screen's client rect
1482    // by `frame_thickness` on each edge, meaning `insets` must contain `frame_thickness`
1483    // on all sides (including the top) to avoid the client area extending onto adjacent
1484    // monitors.
1485    //
1486    // For non-maximized windows, things become complicated:
1487    //
1488    // - On Windows 10
1489    // The top inset must be zero, since if there is any nonclient area, Windows will draw
1490    // a full native titlebar outside the client area. (This doesn't occur in the maximized
1491    // case.)
1492    //
1493    // - On Windows 11
1494    // The top inset is calculated using an empirical formula that I derived through various
1495    // tests. Without this, the top 1-2 rows of pixels in our window would be obscured.
1496    let dpi = unsafe { GetDpiForWindow(handle) };
1497    let frame_thickness = get_frame_thickness(dpi);
1498    let top_insets = if is_maximized {
1499        frame_thickness
1500    } else {
1501        match windows_version {
1502            WindowsVersion::Win10 => 0,
1503            WindowsVersion::Win11 => (dpi as f32 / USER_DEFAULT_SCREEN_DPI as f32).round() as i32,
1504        }
1505    };
1506    RECT {
1507        left: frame_thickness,
1508        top: top_insets,
1509        right: frame_thickness,
1510        bottom: frame_thickness,
1511    }
1512}
1513
1514// there is some additional non-visible space when talking about window
1515// borders on Windows:
1516// - SM_CXSIZEFRAME: The resize handle.
1517// - SM_CXPADDEDBORDER: Additional border space that isn't part of the resize handle.
1518fn get_frame_thickness(dpi: u32) -> i32 {
1519    let resize_frame_thickness = unsafe { GetSystemMetricsForDpi(SM_CXSIZEFRAME, dpi) };
1520    let padding_thickness = unsafe { GetSystemMetricsForDpi(SM_CXPADDEDBORDER, dpi) };
1521    resize_frame_thickness + padding_thickness
1522}
1523
1524fn notify_frame_changed(handle: HWND) {
1525    unsafe {
1526        SetWindowPos(
1527            handle,
1528            None,
1529            0,
1530            0,
1531            0,
1532            0,
1533            SWP_FRAMECHANGED
1534                | SWP_NOACTIVATE
1535                | SWP_NOCOPYBITS
1536                | SWP_NOMOVE
1537                | SWP_NOOWNERZORDER
1538                | SWP_NOREPOSITION
1539                | SWP_NOSENDCHANGING
1540                | SWP_NOSIZE
1541                | SWP_NOZORDER,
1542        )
1543        .log_err();
1544    }
1545}
1546
1547fn start_tracking_mouse(
1548    handle: HWND,
1549    state_ptr: &Rc<WindowsWindowStatePtr>,
1550    flags: TRACKMOUSEEVENT_FLAGS,
1551) {
1552    let mut lock = state_ptr.state.borrow_mut();
1553    if !lock.hovered {
1554        lock.hovered = true;
1555        unsafe {
1556            TrackMouseEvent(&mut TRACKMOUSEEVENT {
1557                cbSize: std::mem::size_of::<TRACKMOUSEEVENT>() as u32,
1558                dwFlags: flags,
1559                hwndTrack: handle,
1560                dwHoverTime: HOVER_DEFAULT,
1561            })
1562            .log_err()
1563        };
1564        if let Some(mut callback) = lock.callbacks.hovered_status_change.take() {
1565            drop(lock);
1566            callback(true);
1567            state_ptr.state.borrow_mut().callbacks.hovered_status_change = Some(callback);
1568        }
1569    }
1570}
1571
1572fn with_input_handler<F, R>(state_ptr: &Rc<WindowsWindowStatePtr>, f: F) -> Option<R>
1573where
1574    F: FnOnce(&mut PlatformInputHandler) -> R,
1575{
1576    let mut input_handler = state_ptr.state.borrow_mut().input_handler.take()?;
1577    let result = f(&mut input_handler);
1578    state_ptr.state.borrow_mut().input_handler = Some(input_handler);
1579    Some(result)
1580}
1581
1582fn with_input_handler_and_scale_factor<F, R>(
1583    state_ptr: &Rc<WindowsWindowStatePtr>,
1584    f: F,
1585) -> Option<R>
1586where
1587    F: FnOnce(&mut PlatformInputHandler, f32) -> Option<R>,
1588{
1589    let mut lock = state_ptr.state.borrow_mut();
1590    let mut input_handler = lock.input_handler.take()?;
1591    let scale_factor = lock.scale_factor;
1592    drop(lock);
1593    let result = f(&mut input_handler, scale_factor);
1594    state_ptr.state.borrow_mut().input_handler = Some(input_handler);
1595    result
1596}