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;
  27pub(crate) const WM_GPUI_KEYBOARD_LAYOUT_CHANGED: u32 = WM_USER + 6;
  28
  29const SIZE_MOVE_LOOP_TIMER_ID: usize = 1;
  30const AUTO_HIDE_TASKBAR_THICKNESS_PX: i32 = 1;
  31
  32impl WindowsWindowInner {
  33    pub(crate) fn handle_msg(
  34        self: &Rc<Self>,
  35        handle: HWND,
  36        msg: u32,
  37        wparam: WPARAM,
  38        lparam: LPARAM,
  39    ) -> LRESULT {
  40        let handled = match msg {
  41            WM_ACTIVATE => self.handle_activate_msg(wparam),
  42            WM_CREATE => self.handle_create_msg(handle),
  43            WM_DEVICECHANGE => self.handle_device_change_msg(handle, wparam),
  44            WM_MOVE => self.handle_move_msg(handle, lparam),
  45            WM_SIZE => self.handle_size_msg(wparam, lparam),
  46            WM_GETMINMAXINFO => self.handle_get_min_max_info_msg(lparam),
  47            WM_ENTERSIZEMOVE | WM_ENTERMENULOOP => self.handle_size_move_loop(handle),
  48            WM_EXITSIZEMOVE | WM_EXITMENULOOP => self.handle_size_move_loop_exit(handle),
  49            WM_TIMER => self.handle_timer_msg(handle, wparam),
  50            WM_NCCALCSIZE => self.handle_calc_client_size(handle, wparam, lparam),
  51            WM_DPICHANGED => self.handle_dpi_changed_msg(handle, wparam, lparam),
  52            WM_DISPLAYCHANGE => self.handle_display_change_msg(handle),
  53            WM_NCHITTEST => self.handle_hit_test_msg(handle, msg, wparam, lparam),
  54            WM_PAINT => self.handle_paint_msg(handle),
  55            WM_CLOSE => self.handle_close_msg(),
  56            WM_DESTROY => self.handle_destroy_msg(handle),
  57            WM_MOUSEMOVE => self.handle_mouse_move_msg(handle, lparam, wparam),
  58            WM_MOUSELEAVE | WM_NCMOUSELEAVE => self.handle_mouse_leave_msg(),
  59            WM_NCMOUSEMOVE => self.handle_nc_mouse_move_msg(handle, lparam),
  60            WM_NCLBUTTONDOWN => {
  61                self.handle_nc_mouse_down_msg(handle, MouseButton::Left, wparam, lparam)
  62            }
  63            WM_NCRBUTTONDOWN => {
  64                self.handle_nc_mouse_down_msg(handle, MouseButton::Right, wparam, lparam)
  65            }
  66            WM_NCMBUTTONDOWN => {
  67                self.handle_nc_mouse_down_msg(handle, MouseButton::Middle, wparam, lparam)
  68            }
  69            WM_NCLBUTTONUP => {
  70                self.handle_nc_mouse_up_msg(handle, MouseButton::Left, wparam, lparam)
  71            }
  72            WM_NCRBUTTONUP => {
  73                self.handle_nc_mouse_up_msg(handle, MouseButton::Right, wparam, lparam)
  74            }
  75            WM_NCMBUTTONUP => {
  76                self.handle_nc_mouse_up_msg(handle, MouseButton::Middle, wparam, lparam)
  77            }
  78            WM_LBUTTONDOWN => self.handle_mouse_down_msg(handle, MouseButton::Left, lparam),
  79            WM_RBUTTONDOWN => self.handle_mouse_down_msg(handle, MouseButton::Right, lparam),
  80            WM_MBUTTONDOWN => self.handle_mouse_down_msg(handle, MouseButton::Middle, lparam),
  81            WM_XBUTTONDOWN => {
  82                self.handle_xbutton_msg(handle, wparam, lparam, Self::handle_mouse_down_msg)
  83            }
  84            WM_LBUTTONUP => self.handle_mouse_up_msg(handle, MouseButton::Left, lparam),
  85            WM_RBUTTONUP => self.handle_mouse_up_msg(handle, MouseButton::Right, lparam),
  86            WM_MBUTTONUP => self.handle_mouse_up_msg(handle, MouseButton::Middle, lparam),
  87            WM_XBUTTONUP => {
  88                self.handle_xbutton_msg(handle, wparam, lparam, Self::handle_mouse_up_msg)
  89            }
  90            WM_MOUSEWHEEL => self.handle_mouse_wheel_msg(handle, wparam, lparam),
  91            WM_MOUSEHWHEEL => self.handle_mouse_horizontal_wheel_msg(handle, wparam, lparam),
  92            WM_SYSKEYDOWN => self.handle_syskeydown_msg(handle, wparam, lparam),
  93            WM_SYSKEYUP => self.handle_syskeyup_msg(handle, wparam, lparam),
  94            WM_SYSCOMMAND => self.handle_system_command(wparam),
  95            WM_KEYDOWN => self.handle_keydown_msg(handle, wparam, lparam),
  96            WM_KEYUP => self.handle_keyup_msg(handle, wparam, lparam),
  97            WM_CHAR => self.handle_char_msg(wparam),
  98            WM_DEADCHAR => self.handle_dead_char_msg(wparam),
  99            WM_IME_STARTCOMPOSITION => self.handle_ime_position(handle),
 100            WM_IME_COMPOSITION => self.handle_ime_composition(handle, lparam),
 101            WM_SETCURSOR => self.handle_set_cursor(handle, lparam),
 102            WM_SETTINGCHANGE => self.handle_system_settings_changed(handle, wparam, lparam),
 103            WM_INPUTLANGCHANGE => self.handle_input_language_changed(),
 104            WM_SHOWWINDOW => self.handle_window_visibility_changed(handle, wparam),
 105            WM_GPUI_CURSOR_STYLE_CHANGED => self.handle_cursor_changed(lparam),
 106            WM_GPUI_FORCE_UPDATE_WINDOW => self.draw_window(handle, true),
 107            _ => None,
 108        };
 109        if let Some(n) = handled {
 110            LRESULT(n)
 111        } else {
 112            unsafe { DefWindowProcW(handle, msg, wparam, lparam) }
 113        }
 114    }
 115
 116    fn handle_move_msg(&self, handle: HWND, lparam: LPARAM) -> Option<isize> {
 117        let mut lock = self.state.borrow_mut();
 118        let origin = logical_point(
 119            lparam.signed_loword() as f32,
 120            lparam.signed_hiword() as f32,
 121            lock.scale_factor,
 122        );
 123        lock.origin = origin;
 124        let size = lock.logical_size;
 125        let center_x = origin.x.0 + size.width.0 / 2.;
 126        let center_y = origin.y.0 + size.height.0 / 2.;
 127        let monitor_bounds = lock.display.bounds();
 128        if center_x < monitor_bounds.left().0
 129            || center_x > monitor_bounds.right().0
 130            || center_y < monitor_bounds.top().0
 131            || center_y > monitor_bounds.bottom().0
 132        {
 133            // center of the window may have moved to another monitor
 134            let monitor = unsafe { MonitorFromWindow(handle, MONITOR_DEFAULTTONULL) };
 135            // minimize the window can trigger this event too, in this case,
 136            // monitor is invalid, we do nothing.
 137            if !monitor.is_invalid() && lock.display.handle != monitor {
 138                // we will get the same monitor if we only have one
 139                lock.display = WindowsDisplay::new_with_handle(monitor);
 140            }
 141        }
 142        if let Some(mut callback) = lock.callbacks.moved.take() {
 143            drop(lock);
 144            callback();
 145            self.state.borrow_mut().callbacks.moved = Some(callback);
 146        }
 147        Some(0)
 148    }
 149
 150    fn handle_get_min_max_info_msg(&self, lparam: LPARAM) -> Option<isize> {
 151        let lock = self.state.borrow();
 152        let min_size = lock.min_size?;
 153        let scale_factor = lock.scale_factor;
 154        let boarder_offset = lock.border_offset;
 155        drop(lock);
 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    }
 165
 166    fn handle_size_msg(&self, wparam: WPARAM, lparam: LPARAM) -> Option<isize> {
 167        let mut lock = self.state.borrow_mut();
 168
 169        // Don't resize the renderer when the window is minimized, but record that it was minimized so
 170        // that on restore the swap chain can be recreated via `update_drawable_size_even_if_unchanged`.
 171        if wparam.0 == SIZE_MINIMIZED as usize {
 172            lock.restore_from_minimized = lock.callbacks.request_frame.take();
 173            return Some(0);
 174        }
 175
 176        let width = lparam.loword().max(1) as i32;
 177        let height = lparam.hiword().max(1) as i32;
 178        let new_size = size(DevicePixels(width), DevicePixels(height));
 179
 180        let scale_factor = lock.scale_factor;
 181        let mut should_resize_renderer = false;
 182        if lock.restore_from_minimized.is_some() {
 183            lock.callbacks.request_frame = lock.restore_from_minimized.take();
 184        } else {
 185            should_resize_renderer = true;
 186        }
 187        drop(lock);
 188
 189        self.handle_size_change(new_size, scale_factor, should_resize_renderer);
 190        Some(0)
 191    }
 192
 193    fn handle_size_change(
 194        &self,
 195        device_size: Size<DevicePixels>,
 196        scale_factor: f32,
 197        should_resize_renderer: bool,
 198    ) {
 199        let new_logical_size = device_size.to_pixels(scale_factor);
 200        let mut lock = self.state.borrow_mut();
 201        lock.logical_size = new_logical_size;
 202        if should_resize_renderer {
 203            lock.renderer.resize(device_size).log_err();
 204        }
 205        if let Some(mut callback) = lock.callbacks.resize.take() {
 206            drop(lock);
 207            callback(new_logical_size, scale_factor);
 208            self.state.borrow_mut().callbacks.resize = Some(callback);
 209        }
 210    }
 211
 212    fn handle_size_move_loop(&self, handle: HWND) -> Option<isize> {
 213        unsafe {
 214            let ret = SetTimer(
 215                Some(handle),
 216                SIZE_MOVE_LOOP_TIMER_ID,
 217                USER_TIMER_MINIMUM,
 218                None,
 219            );
 220            if ret == 0 {
 221                log::error!(
 222                    "unable to create timer: {}",
 223                    std::io::Error::last_os_error()
 224                );
 225            }
 226        }
 227        None
 228    }
 229
 230    fn handle_size_move_loop_exit(&self, handle: HWND) -> Option<isize> {
 231        unsafe {
 232            KillTimer(Some(handle), SIZE_MOVE_LOOP_TIMER_ID).log_err();
 233        }
 234        None
 235    }
 236
 237    fn handle_timer_msg(&self, handle: HWND, wparam: WPARAM) -> Option<isize> {
 238        if wparam.0 == SIZE_MOVE_LOOP_TIMER_ID {
 239            for runnable in self.main_receiver.drain() {
 240                runnable.run();
 241            }
 242            self.handle_paint_msg(handle)
 243        } else {
 244            None
 245        }
 246    }
 247
 248    fn handle_paint_msg(&self, handle: HWND) -> Option<isize> {
 249        self.draw_window(handle, false)
 250    }
 251
 252    fn handle_close_msg(&self) -> Option<isize> {
 253        let mut callback = self.state.borrow_mut().callbacks.should_close.take()?;
 254        let should_close = callback();
 255        self.state.borrow_mut().callbacks.should_close = Some(callback);
 256        if should_close { None } else { Some(0) }
 257    }
 258
 259    fn handle_destroy_msg(&self, handle: HWND) -> Option<isize> {
 260        let callback = {
 261            let mut lock = self.state.borrow_mut();
 262            lock.callbacks.close.take()
 263        };
 264        if let Some(callback) = callback {
 265            callback();
 266        }
 267        unsafe {
 268            PostMessageW(
 269                Some(self.platform_window_handle),
 270                WM_GPUI_CLOSE_ONE_WINDOW,
 271                WPARAM(self.validation_number),
 272                LPARAM(handle.0 as isize),
 273            )
 274            .log_err();
 275        }
 276        Some(0)
 277    }
 278
 279    fn handle_mouse_move_msg(&self, handle: HWND, lparam: LPARAM, wparam: WPARAM) -> Option<isize> {
 280        self.start_tracking_mouse(handle, TME_LEAVE);
 281
 282        let mut lock = self.state.borrow_mut();
 283        let Some(mut func) = lock.callbacks.input.take() else {
 284            return Some(1);
 285        };
 286        let scale_factor = lock.scale_factor;
 287        drop(lock);
 288
 289        let pressed_button = match MODIFIERKEYS_FLAGS(wparam.loword() as u32) {
 290            flags if flags.contains(MK_LBUTTON) => Some(MouseButton::Left),
 291            flags if flags.contains(MK_RBUTTON) => Some(MouseButton::Right),
 292            flags if flags.contains(MK_MBUTTON) => Some(MouseButton::Middle),
 293            flags if flags.contains(MK_XBUTTON1) => {
 294                Some(MouseButton::Navigate(NavigationDirection::Back))
 295            }
 296            flags if flags.contains(MK_XBUTTON2) => {
 297                Some(MouseButton::Navigate(NavigationDirection::Forward))
 298            }
 299            _ => None,
 300        };
 301        let x = lparam.signed_loword() as f32;
 302        let y = lparam.signed_hiword() as f32;
 303        let input = PlatformInput::MouseMove(MouseMoveEvent {
 304            position: logical_point(x, y, scale_factor),
 305            pressed_button,
 306            modifiers: current_modifiers(),
 307        });
 308        let handled = !func(input).propagate;
 309        self.state.borrow_mut().callbacks.input = Some(func);
 310
 311        if handled { Some(0) } else { Some(1) }
 312    }
 313
 314    fn handle_mouse_leave_msg(&self) -> Option<isize> {
 315        let mut lock = self.state.borrow_mut();
 316        lock.hovered = false;
 317        if let Some(mut callback) = lock.callbacks.hovered_status_change.take() {
 318            drop(lock);
 319            callback(false);
 320            self.state.borrow_mut().callbacks.hovered_status_change = Some(callback);
 321        }
 322
 323        Some(0)
 324    }
 325
 326    fn handle_syskeydown_msg(&self, handle: HWND, wparam: WPARAM, lparam: LPARAM) -> Option<isize> {
 327        let mut lock = self.state.borrow_mut();
 328        let input = handle_key_event(handle, wparam, lparam, &mut lock, |keystroke| {
 329            PlatformInput::KeyDown(KeyDownEvent {
 330                keystroke,
 331                is_held: lparam.0 & (0x1 << 30) > 0,
 332            })
 333        })?;
 334        let mut func = lock.callbacks.input.take()?;
 335        drop(lock);
 336
 337        let handled = !func(input).propagate;
 338
 339        let mut lock = self.state.borrow_mut();
 340        lock.callbacks.input = Some(func);
 341
 342        if handled {
 343            lock.system_key_handled = true;
 344            Some(0)
 345        } else {
 346            // we need to call `DefWindowProcW`, or we will lose the system-wide `Alt+F4`, `Alt+{other keys}`
 347            // shortcuts.
 348            None
 349        }
 350    }
 351
 352    fn handle_syskeyup_msg(&self, handle: HWND, wparam: WPARAM, lparam: LPARAM) -> Option<isize> {
 353        let mut lock = self.state.borrow_mut();
 354        let input = handle_key_event(handle, wparam, lparam, &mut lock, |keystroke| {
 355            PlatformInput::KeyUp(KeyUpEvent { keystroke })
 356        })?;
 357        let mut func = lock.callbacks.input.take()?;
 358        drop(lock);
 359        func(input);
 360        self.state.borrow_mut().callbacks.input = Some(func);
 361
 362        // Always return 0 to indicate that the message was handled, so we could properly handle `ModifiersChanged` event.
 363        Some(0)
 364    }
 365
 366    // It's a known bug that you can't trigger `ctrl-shift-0`. See:
 367    // https://superuser.com/questions/1455762/ctrl-shift-number-key-combination-has-stopped-working-for-a-few-numbers
 368    fn handle_keydown_msg(&self, handle: HWND, wparam: WPARAM, lparam: LPARAM) -> Option<isize> {
 369        let mut lock = self.state.borrow_mut();
 370        let Some(input) = handle_key_event(handle, wparam, lparam, &mut lock, |keystroke| {
 371            PlatformInput::KeyDown(KeyDownEvent {
 372                keystroke,
 373                is_held: lparam.0 & (0x1 << 30) > 0,
 374            })
 375        }) else {
 376            return Some(1);
 377        };
 378        drop(lock);
 379
 380        let is_composing = self
 381            .with_input_handler(|input_handler| input_handler.marked_text_range())
 382            .flatten()
 383            .is_some();
 384        if is_composing {
 385            translate_message(handle, wparam, lparam);
 386            return Some(0);
 387        }
 388
 389        let Some(mut func) = self.state.borrow_mut().callbacks.input.take() else {
 390            return Some(1);
 391        };
 392
 393        let handled = !func(input).propagate;
 394
 395        self.state.borrow_mut().callbacks.input = Some(func);
 396
 397        if handled {
 398            Some(0)
 399        } else {
 400            translate_message(handle, wparam, lparam);
 401            Some(1)
 402        }
 403    }
 404
 405    fn handle_keyup_msg(&self, handle: HWND, wparam: WPARAM, lparam: LPARAM) -> Option<isize> {
 406        let mut lock = self.state.borrow_mut();
 407        let Some(input) = handle_key_event(handle, wparam, lparam, &mut lock, |keystroke| {
 408            PlatformInput::KeyUp(KeyUpEvent { keystroke })
 409        }) else {
 410            return Some(1);
 411        };
 412
 413        let Some(mut func) = lock.callbacks.input.take() else {
 414            return Some(1);
 415        };
 416        drop(lock);
 417
 418        let handled = !func(input).propagate;
 419        self.state.borrow_mut().callbacks.input = Some(func);
 420
 421        if handled { Some(0) } else { Some(1) }
 422    }
 423
 424    fn handle_char_msg(&self, wparam: WPARAM) -> Option<isize> {
 425        let input = self.parse_char_message(wparam)?;
 426        self.with_input_handler(|input_handler| {
 427            input_handler.replace_text_in_range(None, &input);
 428        });
 429
 430        Some(0)
 431    }
 432
 433    fn handle_dead_char_msg(&self, wparam: WPARAM) -> Option<isize> {
 434        let ch = char::from_u32(wparam.0 as u32)?.to_string();
 435        self.with_input_handler(|input_handler| {
 436            input_handler.replace_and_mark_text_in_range(None, &ch, None);
 437        });
 438        None
 439    }
 440
 441    fn handle_mouse_down_msg(
 442        &self,
 443        handle: HWND,
 444        button: MouseButton,
 445        lparam: LPARAM,
 446    ) -> Option<isize> {
 447        unsafe { SetCapture(handle) };
 448        let mut lock = self.state.borrow_mut();
 449        let Some(mut func) = lock.callbacks.input.take() else {
 450            return Some(1);
 451        };
 452        let x = lparam.signed_loword();
 453        let y = lparam.signed_hiword();
 454        let physical_point = point(DevicePixels(x as i32), DevicePixels(y as i32));
 455        let click_count = lock.click_state.update(button, physical_point);
 456        let scale_factor = lock.scale_factor;
 457        drop(lock);
 458
 459        let input = PlatformInput::MouseDown(MouseDownEvent {
 460            button,
 461            position: logical_point(x as f32, y as f32, scale_factor),
 462            modifiers: current_modifiers(),
 463            click_count,
 464            first_mouse: false,
 465        });
 466        let handled = !func(input).propagate;
 467        self.state.borrow_mut().callbacks.input = Some(func);
 468
 469        if handled { Some(0) } else { Some(1) }
 470    }
 471
 472    fn handle_mouse_up_msg(
 473        &self,
 474        _handle: HWND,
 475        button: MouseButton,
 476        lparam: LPARAM,
 477    ) -> Option<isize> {
 478        unsafe { ReleaseCapture().log_err() };
 479        let mut lock = self.state.borrow_mut();
 480        let Some(mut func) = lock.callbacks.input.take() else {
 481            return Some(1);
 482        };
 483        let x = lparam.signed_loword() as f32;
 484        let y = lparam.signed_hiword() as f32;
 485        let click_count = lock.click_state.current_count;
 486        let scale_factor = lock.scale_factor;
 487        drop(lock);
 488
 489        let input = PlatformInput::MouseUp(MouseUpEvent {
 490            button,
 491            position: logical_point(x, y, scale_factor),
 492            modifiers: current_modifiers(),
 493            click_count,
 494        });
 495        let handled = !func(input).propagate;
 496        self.state.borrow_mut().callbacks.input = Some(func);
 497
 498        if handled { Some(0) } else { Some(1) }
 499    }
 500
 501    fn handle_xbutton_msg(
 502        &self,
 503        handle: HWND,
 504        wparam: WPARAM,
 505        lparam: LPARAM,
 506        handler: impl Fn(&Self, HWND, MouseButton, LPARAM) -> Option<isize>,
 507    ) -> Option<isize> {
 508        let nav_dir = match wparam.hiword() {
 509            XBUTTON1 => NavigationDirection::Back,
 510            XBUTTON2 => NavigationDirection::Forward,
 511            _ => return Some(1),
 512        };
 513        handler(self, handle, MouseButton::Navigate(nav_dir), lparam)
 514    }
 515
 516    fn handle_mouse_wheel_msg(
 517        &self,
 518        handle: HWND,
 519        wparam: WPARAM,
 520        lparam: LPARAM,
 521    ) -> Option<isize> {
 522        let modifiers = current_modifiers();
 523        let mut lock = self.state.borrow_mut();
 524        let Some(mut func) = lock.callbacks.input.take() else {
 525            return Some(1);
 526        };
 527        let scale_factor = lock.scale_factor;
 528        let wheel_scroll_amount = match modifiers.shift {
 529            true => lock.system_settings.mouse_wheel_settings.wheel_scroll_chars,
 530            false => lock.system_settings.mouse_wheel_settings.wheel_scroll_lines,
 531        };
 532        drop(lock);
 533
 534        let wheel_distance =
 535            (wparam.signed_hiword() as f32 / WHEEL_DELTA as f32) * wheel_scroll_amount as f32;
 536        let mut cursor_point = POINT {
 537            x: lparam.signed_loword().into(),
 538            y: lparam.signed_hiword().into(),
 539        };
 540        unsafe { ScreenToClient(handle, &mut cursor_point).ok().log_err() };
 541        let input = PlatformInput::ScrollWheel(ScrollWheelEvent {
 542            position: logical_point(cursor_point.x as f32, cursor_point.y as f32, scale_factor),
 543            delta: ScrollDelta::Lines(match modifiers.shift {
 544                true => Point {
 545                    x: wheel_distance,
 546                    y: 0.0,
 547                },
 548                false => Point {
 549                    y: wheel_distance,
 550                    x: 0.0,
 551                },
 552            }),
 553            modifiers,
 554            touch_phase: TouchPhase::Moved,
 555        });
 556        let handled = !func(input).propagate;
 557        self.state.borrow_mut().callbacks.input = Some(func);
 558
 559        if handled { Some(0) } else { Some(1) }
 560    }
 561
 562    fn handle_mouse_horizontal_wheel_msg(
 563        &self,
 564        handle: HWND,
 565        wparam: WPARAM,
 566        lparam: LPARAM,
 567    ) -> Option<isize> {
 568        let mut lock = self.state.borrow_mut();
 569        let Some(mut func) = lock.callbacks.input.take() else {
 570            return Some(1);
 571        };
 572        let scale_factor = lock.scale_factor;
 573        let wheel_scroll_chars = lock.system_settings.mouse_wheel_settings.wheel_scroll_chars;
 574        drop(lock);
 575
 576        let wheel_distance =
 577            (-wparam.signed_hiword() as f32 / WHEEL_DELTA as f32) * wheel_scroll_chars as f32;
 578        let mut cursor_point = POINT {
 579            x: lparam.signed_loword().into(),
 580            y: lparam.signed_hiword().into(),
 581        };
 582        unsafe { ScreenToClient(handle, &mut cursor_point).ok().log_err() };
 583        let event = PlatformInput::ScrollWheel(ScrollWheelEvent {
 584            position: logical_point(cursor_point.x as f32, cursor_point.y as f32, scale_factor),
 585            delta: ScrollDelta::Lines(Point {
 586                x: wheel_distance,
 587                y: 0.0,
 588            }),
 589            modifiers: current_modifiers(),
 590            touch_phase: TouchPhase::Moved,
 591        });
 592        let handled = !func(event).propagate;
 593        self.state.borrow_mut().callbacks.input = Some(func);
 594
 595        if handled { Some(0) } else { Some(1) }
 596    }
 597
 598    fn retrieve_caret_position(&self) -> Option<POINT> {
 599        self.with_input_handler_and_scale_factor(|input_handler, scale_factor| {
 600            let caret_range = input_handler.selected_text_range(false)?;
 601            let caret_position = input_handler.bounds_for_range(caret_range.range)?;
 602            Some(POINT {
 603                // logical to physical
 604                x: (caret_position.origin.x.0 * scale_factor) as i32,
 605                y: (caret_position.origin.y.0 * scale_factor) as i32
 606                    + ((caret_position.size.height.0 * scale_factor) as i32 / 2),
 607            })
 608        })
 609    }
 610
 611    fn handle_ime_position(&self, handle: HWND) -> Option<isize> {
 612        unsafe {
 613            let ctx = ImmGetContext(handle);
 614
 615            let Some(caret_position) = self.retrieve_caret_position() else {
 616                return Some(0);
 617            };
 618            {
 619                let config = COMPOSITIONFORM {
 620                    dwStyle: CFS_POINT,
 621                    ptCurrentPos: caret_position,
 622                    ..Default::default()
 623                };
 624                ImmSetCompositionWindow(ctx, &config as _).ok().log_err();
 625            }
 626            {
 627                let config = CANDIDATEFORM {
 628                    dwStyle: CFS_CANDIDATEPOS,
 629                    ptCurrentPos: caret_position,
 630                    ..Default::default()
 631                };
 632                ImmSetCandidateWindow(ctx, &config as _).ok().log_err();
 633            }
 634            ImmReleaseContext(handle, ctx).ok().log_err();
 635            Some(0)
 636        }
 637    }
 638
 639    fn handle_ime_composition(&self, handle: HWND, lparam: LPARAM) -> Option<isize> {
 640        let ctx = unsafe { ImmGetContext(handle) };
 641        let result = self.handle_ime_composition_inner(ctx, lparam);
 642        unsafe { ImmReleaseContext(handle, ctx).ok().log_err() };
 643        result
 644    }
 645
 646    fn handle_ime_composition_inner(&self, ctx: HIMC, lparam: LPARAM) -> Option<isize> {
 647        let lparam = lparam.0 as u32;
 648        if lparam == 0 {
 649            // Japanese IME may send this message with lparam = 0, which indicates that
 650            // there is no composition string.
 651            self.with_input_handler(|input_handler| {
 652                input_handler.replace_text_in_range(None, "");
 653            })?;
 654            Some(0)
 655        } else {
 656            if lparam & GCS_COMPSTR.0 > 0 {
 657                let comp_string = parse_ime_composition_string(ctx, GCS_COMPSTR)?;
 658                let caret_pos =
 659                    (!comp_string.is_empty() && lparam & GCS_CURSORPOS.0 > 0).then(|| {
 660                        let pos = retrieve_composition_cursor_position(ctx);
 661                        pos..pos
 662                    });
 663                self.with_input_handler(|input_handler| {
 664                    input_handler.replace_and_mark_text_in_range(None, &comp_string, caret_pos);
 665                })?;
 666            }
 667            if lparam & GCS_RESULTSTR.0 > 0 {
 668                let comp_result = parse_ime_composition_string(ctx, GCS_RESULTSTR)?;
 669                self.with_input_handler(|input_handler| {
 670                    input_handler.replace_text_in_range(None, &comp_result);
 671                })?;
 672                return Some(0);
 673            }
 674
 675            // currently, we don't care other stuff
 676            None
 677        }
 678    }
 679
 680    /// SEE: https://learn.microsoft.com/en-us/windows/win32/winmsg/wm-nccalcsize
 681    fn handle_calc_client_size(
 682        &self,
 683        handle: HWND,
 684        wparam: WPARAM,
 685        lparam: LPARAM,
 686    ) -> Option<isize> {
 687        if !self.hide_title_bar || self.state.borrow().is_fullscreen() || wparam.0 == 0 {
 688            return None;
 689        }
 690
 691        let is_maximized = self.state.borrow().is_maximized();
 692        let insets = get_client_area_insets(handle, is_maximized, self.windows_version);
 693        // wparam is TRUE so lparam points to an NCCALCSIZE_PARAMS structure
 694        let mut params = lparam.0 as *mut NCCALCSIZE_PARAMS;
 695        let mut requested_client_rect = unsafe { &mut ((*params).rgrc) };
 696
 697        requested_client_rect[0].left += insets.left;
 698        requested_client_rect[0].top += insets.top;
 699        requested_client_rect[0].right -= insets.right;
 700        requested_client_rect[0].bottom -= insets.bottom;
 701
 702        // Fix auto hide taskbar not showing. This solution is based on the approach
 703        // used by Chrome. However, it may result in one row of pixels being obscured
 704        // in our client area. But as Chrome says, "there seems to be no better solution."
 705        if is_maximized
 706            && let Some(ref taskbar_position) = self
 707                .state
 708                .borrow()
 709                .system_settings
 710                .auto_hide_taskbar_position
 711        {
 712            // For the auto-hide taskbar, adjust in by 1 pixel on taskbar edge,
 713            // so the window isn't treated as a "fullscreen app", which would cause
 714            // the taskbar to disappear.
 715            match taskbar_position {
 716                AutoHideTaskbarPosition::Left => {
 717                    requested_client_rect[0].left += AUTO_HIDE_TASKBAR_THICKNESS_PX
 718                }
 719                AutoHideTaskbarPosition::Top => {
 720                    requested_client_rect[0].top += AUTO_HIDE_TASKBAR_THICKNESS_PX
 721                }
 722                AutoHideTaskbarPosition::Right => {
 723                    requested_client_rect[0].right -= AUTO_HIDE_TASKBAR_THICKNESS_PX
 724                }
 725                AutoHideTaskbarPosition::Bottom => {
 726                    requested_client_rect[0].bottom -= AUTO_HIDE_TASKBAR_THICKNESS_PX
 727                }
 728            }
 729        }
 730
 731        Some(0)
 732    }
 733
 734    fn handle_activate_msg(self: &Rc<Self>, wparam: WPARAM) -> Option<isize> {
 735        let activated = wparam.loword() > 0;
 736        let this = self.clone();
 737        self.executor
 738            .spawn(async move {
 739                let mut lock = this.state.borrow_mut();
 740                if let Some(mut func) = lock.callbacks.active_status_change.take() {
 741                    drop(lock);
 742                    func(activated);
 743                    this.state.borrow_mut().callbacks.active_status_change = Some(func);
 744                }
 745            })
 746            .detach();
 747
 748        None
 749    }
 750
 751    fn handle_create_msg(&self, handle: HWND) -> Option<isize> {
 752        if self.hide_title_bar {
 753            notify_frame_changed(handle);
 754            Some(0)
 755        } else {
 756            None
 757        }
 758    }
 759
 760    fn handle_dpi_changed_msg(
 761        &self,
 762        handle: HWND,
 763        wparam: WPARAM,
 764        lparam: LPARAM,
 765    ) -> Option<isize> {
 766        let new_dpi = wparam.loword() as f32;
 767        let mut lock = self.state.borrow_mut();
 768        let is_maximized = lock.is_maximized();
 769        let new_scale_factor = new_dpi / USER_DEFAULT_SCREEN_DPI as f32;
 770        lock.scale_factor = new_scale_factor;
 771        lock.border_offset.update(handle).log_err();
 772        drop(lock);
 773
 774        let rect = unsafe { &*(lparam.0 as *const RECT) };
 775        let width = rect.right - rect.left;
 776        let height = rect.bottom - rect.top;
 777        // this will emit `WM_SIZE` and `WM_MOVE` right here
 778        // even before this function returns
 779        // the new size is handled in `WM_SIZE`
 780        unsafe {
 781            SetWindowPos(
 782                handle,
 783                None,
 784                rect.left,
 785                rect.top,
 786                width,
 787                height,
 788                SWP_NOZORDER | SWP_NOACTIVATE,
 789            )
 790            .context("unable to set window position after dpi has changed")
 791            .log_err();
 792        }
 793
 794        // When maximized, SetWindowPos doesn't send WM_SIZE, so we need to manually
 795        // update the size and call the resize callback
 796        if is_maximized {
 797            let device_size = size(DevicePixels(width), DevicePixels(height));
 798            self.handle_size_change(device_size, new_scale_factor, true);
 799        }
 800
 801        Some(0)
 802    }
 803
 804    /// The following conditions will trigger this event:
 805    /// 1. The monitor on which the window is located goes offline or changes resolution.
 806    /// 2. Another monitor goes offline, is plugged in, or changes resolution.
 807    ///
 808    /// In either case, the window will only receive information from the monitor on which
 809    /// it is located.
 810    ///
 811    /// For example, in the case of condition 2, where the monitor on which the window is
 812    /// located has actually changed nothing, it will still receive this event.
 813    fn handle_display_change_msg(&self, handle: HWND) -> Option<isize> {
 814        // NOTE:
 815        // Even the `lParam` holds the resolution of the screen, we just ignore it.
 816        // Because WM_DPICHANGED, WM_MOVE, WM_SIZE will come first, window reposition and resize
 817        // are handled there.
 818        // So we only care about if monitor is disconnected.
 819        let previous_monitor = self.state.borrow().display;
 820        if WindowsDisplay::is_connected(previous_monitor.handle) {
 821            // we are fine, other display changed
 822            return None;
 823        }
 824        // display disconnected
 825        // in this case, the OS will move our window to another monitor, and minimize it.
 826        // we deminimize the window and query the monitor after moving
 827        unsafe {
 828            let _ = ShowWindow(handle, SW_SHOWNORMAL);
 829        };
 830        let new_monitor = unsafe { MonitorFromWindow(handle, MONITOR_DEFAULTTONULL) };
 831        // all monitors disconnected
 832        if new_monitor.is_invalid() {
 833            log::error!("No monitor detected!");
 834            return None;
 835        }
 836        let new_display = WindowsDisplay::new_with_handle(new_monitor);
 837        self.state.borrow_mut().display = new_display;
 838        Some(0)
 839    }
 840
 841    fn handle_hit_test_msg(
 842        &self,
 843        handle: HWND,
 844        msg: u32,
 845        wparam: WPARAM,
 846        lparam: LPARAM,
 847    ) -> Option<isize> {
 848        if !self.is_movable || self.state.borrow().is_fullscreen() {
 849            return None;
 850        }
 851
 852        let mut lock = self.state.borrow_mut();
 853        if let Some(mut callback) = lock.callbacks.hit_test_window_control.take() {
 854            drop(lock);
 855            let area = callback();
 856            self.state.borrow_mut().callbacks.hit_test_window_control = Some(callback);
 857            if let Some(area) = area {
 858                return match area {
 859                    WindowControlArea::Drag => Some(HTCAPTION as _),
 860                    WindowControlArea::Close => Some(HTCLOSE as _),
 861                    WindowControlArea::Max => Some(HTMAXBUTTON as _),
 862                    WindowControlArea::Min => Some(HTMINBUTTON as _),
 863                };
 864            }
 865        } else {
 866            drop(lock);
 867        }
 868
 869        if !self.hide_title_bar {
 870            // If the OS draws the title bar, we don't need to handle hit test messages.
 871            return None;
 872        }
 873
 874        // default handler for resize areas
 875        let hit = unsafe { DefWindowProcW(handle, msg, wparam, lparam) };
 876        if matches!(
 877            hit.0 as u32,
 878            HTNOWHERE
 879                | HTRIGHT
 880                | HTLEFT
 881                | HTTOPLEFT
 882                | HTTOP
 883                | HTTOPRIGHT
 884                | HTBOTTOMRIGHT
 885                | HTBOTTOM
 886                | HTBOTTOMLEFT
 887        ) {
 888            return Some(hit.0);
 889        }
 890
 891        if self.state.borrow().is_fullscreen() {
 892            return Some(HTCLIENT as _);
 893        }
 894
 895        let dpi = unsafe { GetDpiForWindow(handle) };
 896        let frame_y = unsafe { GetSystemMetricsForDpi(SM_CYFRAME, dpi) };
 897
 898        let mut cursor_point = POINT {
 899            x: lparam.signed_loword().into(),
 900            y: lparam.signed_hiword().into(),
 901        };
 902        unsafe { ScreenToClient(handle, &mut cursor_point).ok().log_err() };
 903        if !self.state.borrow().is_maximized() && cursor_point.y >= 0 && cursor_point.y <= frame_y {
 904            return Some(HTTOP as _);
 905        }
 906
 907        Some(HTCLIENT as _)
 908    }
 909
 910    fn handle_nc_mouse_move_msg(&self, handle: HWND, lparam: LPARAM) -> Option<isize> {
 911        self.start_tracking_mouse(handle, TME_LEAVE | TME_NONCLIENT);
 912
 913        let mut lock = self.state.borrow_mut();
 914        let mut func = lock.callbacks.input.take()?;
 915        let scale_factor = lock.scale_factor;
 916        drop(lock);
 917
 918        let mut cursor_point = POINT {
 919            x: lparam.signed_loword().into(),
 920            y: lparam.signed_hiword().into(),
 921        };
 922        unsafe { ScreenToClient(handle, &mut cursor_point).ok().log_err() };
 923        let input = PlatformInput::MouseMove(MouseMoveEvent {
 924            position: logical_point(cursor_point.x as f32, cursor_point.y as f32, scale_factor),
 925            pressed_button: None,
 926            modifiers: current_modifiers(),
 927        });
 928        let handled = !func(input).propagate;
 929        self.state.borrow_mut().callbacks.input = Some(func);
 930
 931        if handled { Some(0) } else { None }
 932    }
 933
 934    fn handle_nc_mouse_down_msg(
 935        &self,
 936        handle: HWND,
 937        button: MouseButton,
 938        wparam: WPARAM,
 939        lparam: LPARAM,
 940    ) -> Option<isize> {
 941        let mut lock = self.state.borrow_mut();
 942        if let Some(mut func) = lock.callbacks.input.take() {
 943            let scale_factor = lock.scale_factor;
 944            let mut cursor_point = POINT {
 945                x: lparam.signed_loword().into(),
 946                y: lparam.signed_hiword().into(),
 947            };
 948            unsafe { ScreenToClient(handle, &mut cursor_point).ok().log_err() };
 949            let physical_point = point(DevicePixels(cursor_point.x), DevicePixels(cursor_point.y));
 950            let click_count = lock.click_state.update(button, physical_point);
 951            drop(lock);
 952
 953            let input = PlatformInput::MouseDown(MouseDownEvent {
 954                button,
 955                position: logical_point(cursor_point.x as f32, cursor_point.y as f32, scale_factor),
 956                modifiers: current_modifiers(),
 957                click_count,
 958                first_mouse: false,
 959            });
 960            let result = func(input);
 961            let handled = !result.propagate || result.default_prevented;
 962            self.state.borrow_mut().callbacks.input = Some(func);
 963
 964            if handled {
 965                return Some(0);
 966            }
 967        } else {
 968            drop(lock);
 969        };
 970
 971        // Since these are handled in handle_nc_mouse_up_msg we must prevent the default window proc
 972        if button == MouseButton::Left {
 973            match wparam.0 as u32 {
 974                HTMINBUTTON => self.state.borrow_mut().nc_button_pressed = Some(HTMINBUTTON),
 975                HTMAXBUTTON => self.state.borrow_mut().nc_button_pressed = Some(HTMAXBUTTON),
 976                HTCLOSE => self.state.borrow_mut().nc_button_pressed = Some(HTCLOSE),
 977                _ => return None,
 978            };
 979            Some(0)
 980        } else {
 981            None
 982        }
 983    }
 984
 985    fn handle_nc_mouse_up_msg(
 986        &self,
 987        handle: HWND,
 988        button: MouseButton,
 989        wparam: WPARAM,
 990        lparam: LPARAM,
 991    ) -> Option<isize> {
 992        let mut lock = self.state.borrow_mut();
 993        if let Some(mut func) = lock.callbacks.input.take() {
 994            let scale_factor = lock.scale_factor;
 995            drop(lock);
 996
 997            let mut cursor_point = POINT {
 998                x: lparam.signed_loword().into(),
 999                y: lparam.signed_hiword().into(),
1000            };
1001            unsafe { ScreenToClient(handle, &mut cursor_point).ok().log_err() };
1002            let input = PlatformInput::MouseUp(MouseUpEvent {
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: 1,
1007            });
1008            let handled = !func(input).propagate;
1009            self.state.borrow_mut().callbacks.input = Some(func);
1010
1011            if handled {
1012                return Some(0);
1013            }
1014        } else {
1015            drop(lock);
1016        }
1017
1018        let last_pressed = self.state.borrow_mut().nc_button_pressed.take();
1019        if button == MouseButton::Left
1020            && let Some(last_pressed) = last_pressed
1021        {
1022            let handled = match (wparam.0 as u32, last_pressed) {
1023                (HTMINBUTTON, HTMINBUTTON) => {
1024                    unsafe { ShowWindowAsync(handle, SW_MINIMIZE).ok().log_err() };
1025                    true
1026                }
1027                (HTMAXBUTTON, HTMAXBUTTON) => {
1028                    if self.state.borrow().is_maximized() {
1029                        unsafe { ShowWindowAsync(handle, SW_NORMAL).ok().log_err() };
1030                    } else {
1031                        unsafe { ShowWindowAsync(handle, SW_MAXIMIZE).ok().log_err() };
1032                    }
1033                    true
1034                }
1035                (HTCLOSE, HTCLOSE) => {
1036                    unsafe {
1037                        PostMessageW(Some(handle), WM_CLOSE, WPARAM::default(), LPARAM::default())
1038                            .log_err()
1039                    };
1040                    true
1041                }
1042                _ => false,
1043            };
1044            if handled {
1045                return Some(0);
1046            }
1047        }
1048
1049        None
1050    }
1051
1052    fn handle_cursor_changed(&self, lparam: LPARAM) -> Option<isize> {
1053        let mut state = self.state.borrow_mut();
1054        let had_cursor = state.current_cursor.is_some();
1055
1056        state.current_cursor = if lparam.0 == 0 {
1057            None
1058        } else {
1059            Some(HCURSOR(lparam.0 as _))
1060        };
1061
1062        if had_cursor != state.current_cursor.is_some() {
1063            unsafe { SetCursor(state.current_cursor) };
1064        }
1065
1066        Some(0)
1067    }
1068
1069    fn handle_set_cursor(&self, handle: HWND, lparam: LPARAM) -> Option<isize> {
1070        if unsafe { !IsWindowEnabled(handle).as_bool() }
1071            || matches!(
1072                lparam.loword() as u32,
1073                HTLEFT
1074                    | HTRIGHT
1075                    | HTTOP
1076                    | HTTOPLEFT
1077                    | HTTOPRIGHT
1078                    | HTBOTTOM
1079                    | HTBOTTOMLEFT
1080                    | HTBOTTOMRIGHT
1081            )
1082        {
1083            return None;
1084        }
1085        unsafe {
1086            SetCursor(self.state.borrow().current_cursor);
1087        };
1088        Some(1)
1089    }
1090
1091    fn handle_system_settings_changed(
1092        &self,
1093        handle: HWND,
1094        wparam: WPARAM,
1095        lparam: LPARAM,
1096    ) -> Option<isize> {
1097        if wparam.0 != 0 {
1098            let mut lock = self.state.borrow_mut();
1099            let display = lock.display;
1100            lock.system_settings.update(display, wparam.0);
1101            lock.click_state.system_update(wparam.0);
1102            lock.border_offset.update(handle).log_err();
1103        } else {
1104            self.handle_system_theme_changed(handle, lparam)?;
1105        };
1106        // Force to trigger WM_NCCALCSIZE event to ensure that we handle auto hide
1107        // taskbar correctly.
1108        notify_frame_changed(handle);
1109
1110        Some(0)
1111    }
1112
1113    fn handle_system_command(&self, wparam: WPARAM) -> Option<isize> {
1114        if wparam.0 == SC_KEYMENU as usize {
1115            let mut lock = self.state.borrow_mut();
1116            if lock.system_key_handled {
1117                lock.system_key_handled = false;
1118                return Some(0);
1119            }
1120        }
1121        None
1122    }
1123
1124    fn handle_system_theme_changed(&self, handle: HWND, lparam: LPARAM) -> Option<isize> {
1125        // lParam is a pointer to a string that indicates the area containing the system parameter
1126        // that was changed.
1127        let parameter = PCWSTR::from_raw(lparam.0 as _);
1128        if unsafe { !parameter.is_null() && !parameter.is_empty() }
1129            && let Some(parameter_string) = unsafe { parameter.to_string() }.log_err()
1130        {
1131            log::info!("System settings changed: {}", parameter_string);
1132            if parameter_string.as_str() == "ImmersiveColorSet" {
1133                let new_appearance = system_appearance()
1134                    .context("unable to get system appearance when handling ImmersiveColorSet")
1135                    .log_err()?;
1136                let mut lock = self.state.borrow_mut();
1137                if new_appearance != lock.appearance {
1138                    lock.appearance = new_appearance;
1139                    let mut callback = lock.callbacks.appearance_changed.take()?;
1140                    drop(lock);
1141                    callback();
1142                    self.state.borrow_mut().callbacks.appearance_changed = Some(callback);
1143                    configure_dwm_dark_mode(handle, new_appearance);
1144                }
1145            }
1146        }
1147        Some(0)
1148    }
1149
1150    fn handle_input_language_changed(&self) -> Option<isize> {
1151        unsafe {
1152            PostMessageW(
1153                Some(self.platform_window_handle),
1154                WM_GPUI_KEYBOARD_LAYOUT_CHANGED,
1155                WPARAM(self.validation_number),
1156                LPARAM(0),
1157            )
1158            .log_err();
1159        }
1160        Some(0)
1161    }
1162
1163    fn handle_window_visibility_changed(&self, handle: HWND, wparam: WPARAM) -> Option<isize> {
1164        if wparam.0 == 1 {
1165            self.draw_window(handle, false);
1166        }
1167        None
1168    }
1169
1170    fn handle_device_change_msg(&self, handle: HWND, wparam: WPARAM) -> Option<isize> {
1171        if wparam.0 == DBT_DEVNODES_CHANGED as usize {
1172            // The reason for sending this message is to actually trigger a redraw of the window.
1173            unsafe {
1174                PostMessageW(
1175                    Some(handle),
1176                    WM_GPUI_FORCE_UPDATE_WINDOW,
1177                    WPARAM(0),
1178                    LPARAM(0),
1179                )
1180                .log_err();
1181            }
1182            // If the GPU device is lost, this redraw will take care of recreating the device context.
1183            // The WM_GPUI_FORCE_UPDATE_WINDOW message will take care of redrawing the window, after
1184            // the device context has been recreated.
1185            self.draw_window(handle, true)
1186        } else {
1187            // Other device change messages are not handled.
1188            None
1189        }
1190    }
1191
1192    #[inline]
1193    fn draw_window(&self, handle: HWND, force_render: bool) -> Option<isize> {
1194        let mut request_frame = self.state.borrow_mut().callbacks.request_frame.take()?;
1195        request_frame(RequestFrameOptions {
1196            require_presentation: false,
1197            force_render,
1198        });
1199        self.state.borrow_mut().callbacks.request_frame = Some(request_frame);
1200        unsafe { ValidateRect(Some(handle), None).ok().log_err() };
1201        Some(0)
1202    }
1203
1204    #[inline]
1205    fn parse_char_message(&self, wparam: WPARAM) -> Option<String> {
1206        let code_point = wparam.loword();
1207        let mut lock = self.state.borrow_mut();
1208        // https://www.unicode.org/versions/Unicode16.0.0/core-spec/chapter-3/#G2630
1209        match code_point {
1210            0xD800..=0xDBFF => {
1211                // High surrogate, wait for low surrogate
1212                lock.pending_surrogate = Some(code_point);
1213                None
1214            }
1215            0xDC00..=0xDFFF => {
1216                if let Some(high_surrogate) = lock.pending_surrogate.take() {
1217                    // Low surrogate, combine with pending high surrogate
1218                    String::from_utf16(&[high_surrogate, code_point]).ok()
1219                } else {
1220                    // Invalid low surrogate without a preceding high surrogate
1221                    log::warn!(
1222                        "Received low surrogate without a preceding high surrogate: {code_point:x}"
1223                    );
1224                    None
1225                }
1226            }
1227            _ => {
1228                lock.pending_surrogate = None;
1229                char::from_u32(code_point as u32)
1230                    .filter(|c| !c.is_control())
1231                    .map(|c| c.to_string())
1232            }
1233        }
1234    }
1235
1236    fn start_tracking_mouse(&self, handle: HWND, flags: TRACKMOUSEEVENT_FLAGS) {
1237        let mut lock = self.state.borrow_mut();
1238        if !lock.hovered {
1239            lock.hovered = true;
1240            unsafe {
1241                TrackMouseEvent(&mut TRACKMOUSEEVENT {
1242                    cbSize: std::mem::size_of::<TRACKMOUSEEVENT>() as u32,
1243                    dwFlags: flags,
1244                    hwndTrack: handle,
1245                    dwHoverTime: HOVER_DEFAULT,
1246                })
1247                .log_err()
1248            };
1249            if let Some(mut callback) = lock.callbacks.hovered_status_change.take() {
1250                drop(lock);
1251                callback(true);
1252                self.state.borrow_mut().callbacks.hovered_status_change = Some(callback);
1253            }
1254        }
1255    }
1256
1257    fn with_input_handler<F, R>(&self, f: F) -> Option<R>
1258    where
1259        F: FnOnce(&mut PlatformInputHandler) -> R,
1260    {
1261        let mut input_handler = self.state.borrow_mut().input_handler.take()?;
1262        let result = f(&mut input_handler);
1263        self.state.borrow_mut().input_handler = Some(input_handler);
1264        Some(result)
1265    }
1266
1267    fn with_input_handler_and_scale_factor<F, R>(&self, f: F) -> Option<R>
1268    where
1269        F: FnOnce(&mut PlatformInputHandler, f32) -> Option<R>,
1270    {
1271        let mut lock = self.state.borrow_mut();
1272        let mut input_handler = lock.input_handler.take()?;
1273        let scale_factor = lock.scale_factor;
1274        drop(lock);
1275        let result = f(&mut input_handler, scale_factor);
1276        self.state.borrow_mut().input_handler = Some(input_handler);
1277        result
1278    }
1279}
1280
1281#[inline]
1282fn translate_message(handle: HWND, wparam: WPARAM, lparam: LPARAM) {
1283    let msg = MSG {
1284        hwnd: handle,
1285        message: WM_KEYDOWN,
1286        wParam: wparam,
1287        lParam: lparam,
1288        // It seems like leaving the following two parameters empty doesn't break key events, they still work as expected.
1289        // But if any bugs pop up after this PR, this is probably the place to look first.
1290        time: 0,
1291        pt: POINT::default(),
1292    };
1293    unsafe { TranslateMessage(&msg).ok().log_err() };
1294}
1295
1296fn handle_key_event<F>(
1297    handle: HWND,
1298    wparam: WPARAM,
1299    lparam: LPARAM,
1300    state: &mut WindowsWindowState,
1301    f: F,
1302) -> Option<PlatformInput>
1303where
1304    F: FnOnce(Keystroke) -> PlatformInput,
1305{
1306    let virtual_key = VIRTUAL_KEY(wparam.loword());
1307    let mut modifiers = current_modifiers();
1308
1309    match virtual_key {
1310        VK_SHIFT | VK_CONTROL | VK_MENU | VK_LWIN | VK_RWIN => {
1311            if state
1312                .last_reported_modifiers
1313                .is_some_and(|prev_modifiers| prev_modifiers == modifiers)
1314            {
1315                return None;
1316            }
1317            state.last_reported_modifiers = Some(modifiers);
1318            Some(PlatformInput::ModifiersChanged(ModifiersChangedEvent {
1319                modifiers,
1320                capslock: current_capslock(),
1321            }))
1322        }
1323        VK_PACKET => {
1324            translate_message(handle, wparam, lparam);
1325            None
1326        }
1327        VK_CAPITAL => {
1328            let capslock = current_capslock();
1329            if state
1330                .last_reported_capslock
1331                .is_some_and(|prev_capslock| prev_capslock == capslock)
1332            {
1333                return None;
1334            }
1335            state.last_reported_capslock = Some(capslock);
1336            Some(PlatformInput::ModifiersChanged(ModifiersChangedEvent {
1337                modifiers,
1338                capslock,
1339            }))
1340        }
1341        vkey => {
1342            let vkey = if vkey == VK_PROCESSKEY {
1343                VIRTUAL_KEY(unsafe { ImmGetVirtualKey(handle) } as u16)
1344            } else {
1345                vkey
1346            };
1347            let keystroke = parse_normal_key(vkey, lparam, modifiers)?;
1348            Some(f(keystroke))
1349        }
1350    }
1351}
1352
1353fn parse_immutable(vkey: VIRTUAL_KEY) -> Option<String> {
1354    Some(
1355        match vkey {
1356            VK_SPACE => "space",
1357            VK_BACK => "backspace",
1358            VK_RETURN => "enter",
1359            VK_TAB => "tab",
1360            VK_UP => "up",
1361            VK_DOWN => "down",
1362            VK_RIGHT => "right",
1363            VK_LEFT => "left",
1364            VK_HOME => "home",
1365            VK_END => "end",
1366            VK_PRIOR => "pageup",
1367            VK_NEXT => "pagedown",
1368            VK_BROWSER_BACK => "back",
1369            VK_BROWSER_FORWARD => "forward",
1370            VK_ESCAPE => "escape",
1371            VK_INSERT => "insert",
1372            VK_DELETE => "delete",
1373            VK_APPS => "menu",
1374            VK_F1 => "f1",
1375            VK_F2 => "f2",
1376            VK_F3 => "f3",
1377            VK_F4 => "f4",
1378            VK_F5 => "f5",
1379            VK_F6 => "f6",
1380            VK_F7 => "f7",
1381            VK_F8 => "f8",
1382            VK_F9 => "f9",
1383            VK_F10 => "f10",
1384            VK_F11 => "f11",
1385            VK_F12 => "f12",
1386            VK_F13 => "f13",
1387            VK_F14 => "f14",
1388            VK_F15 => "f15",
1389            VK_F16 => "f16",
1390            VK_F17 => "f17",
1391            VK_F18 => "f18",
1392            VK_F19 => "f19",
1393            VK_F20 => "f20",
1394            VK_F21 => "f21",
1395            VK_F22 => "f22",
1396            VK_F23 => "f23",
1397            VK_F24 => "f24",
1398            _ => return None,
1399        }
1400        .to_string(),
1401    )
1402}
1403
1404fn parse_normal_key(
1405    vkey: VIRTUAL_KEY,
1406    lparam: LPARAM,
1407    mut modifiers: Modifiers,
1408) -> Option<Keystroke> {
1409    let mut key_char = None;
1410    let key = parse_immutable(vkey).or_else(|| {
1411        let scan_code = lparam.hiword() & 0xFF;
1412        key_char = generate_key_char(
1413            vkey,
1414            scan_code as u32,
1415            modifiers.control,
1416            modifiers.shift,
1417            modifiers.alt,
1418        );
1419        get_keystroke_key(vkey, scan_code as u32, &mut modifiers)
1420    })?;
1421    Some(Keystroke {
1422        modifiers,
1423        key,
1424        key_char,
1425    })
1426}
1427
1428fn parse_ime_composition_string(ctx: HIMC, comp_type: IME_COMPOSITION_STRING) -> Option<String> {
1429    unsafe {
1430        let string_len = ImmGetCompositionStringW(ctx, comp_type, None, 0);
1431        if string_len >= 0 {
1432            let mut buffer = vec![0u8; string_len as usize + 2];
1433            ImmGetCompositionStringW(
1434                ctx,
1435                comp_type,
1436                Some(buffer.as_mut_ptr() as _),
1437                string_len as _,
1438            );
1439            let wstring = std::slice::from_raw_parts::<u16>(
1440                buffer.as_mut_ptr().cast::<u16>(),
1441                string_len as usize / 2,
1442            );
1443            Some(String::from_utf16_lossy(wstring))
1444        } else {
1445            None
1446        }
1447    }
1448}
1449
1450#[inline]
1451fn retrieve_composition_cursor_position(ctx: HIMC) -> usize {
1452    unsafe { ImmGetCompositionStringW(ctx, GCS_CURSORPOS, None, 0) as usize }
1453}
1454
1455#[inline]
1456fn is_virtual_key_pressed(vkey: VIRTUAL_KEY) -> bool {
1457    unsafe { GetKeyState(vkey.0 as i32) < 0 }
1458}
1459
1460#[inline]
1461pub(crate) fn current_modifiers() -> Modifiers {
1462    Modifiers {
1463        control: is_virtual_key_pressed(VK_CONTROL),
1464        alt: is_virtual_key_pressed(VK_MENU),
1465        shift: is_virtual_key_pressed(VK_SHIFT),
1466        platform: is_virtual_key_pressed(VK_LWIN) || is_virtual_key_pressed(VK_RWIN),
1467        function: false,
1468    }
1469}
1470
1471#[inline]
1472pub(crate) fn current_capslock() -> Capslock {
1473    let on = unsafe { GetKeyState(VK_CAPITAL.0 as i32) & 1 } > 0;
1474    Capslock { on }
1475}
1476
1477fn get_client_area_insets(
1478    handle: HWND,
1479    is_maximized: bool,
1480    windows_version: WindowsVersion,
1481) -> RECT {
1482    // For maximized windows, Windows outdents the window rect from the screen's client rect
1483    // by `frame_thickness` on each edge, meaning `insets` must contain `frame_thickness`
1484    // on all sides (including the top) to avoid the client area extending onto adjacent
1485    // monitors.
1486    //
1487    // For non-maximized windows, things become complicated:
1488    //
1489    // - On Windows 10
1490    // The top inset must be zero, since if there is any nonclient area, Windows will draw
1491    // a full native titlebar outside the client area. (This doesn't occur in the maximized
1492    // case.)
1493    //
1494    // - On Windows 11
1495    // The top inset is calculated using an empirical formula that I derived through various
1496    // tests. Without this, the top 1-2 rows of pixels in our window would be obscured.
1497    let dpi = unsafe { GetDpiForWindow(handle) };
1498    let frame_thickness = get_frame_thickness(dpi);
1499    let top_insets = if is_maximized {
1500        frame_thickness
1501    } else {
1502        match windows_version {
1503            WindowsVersion::Win10 => 0,
1504            WindowsVersion::Win11 => (dpi as f32 / USER_DEFAULT_SCREEN_DPI as f32).round() as i32,
1505        }
1506    };
1507    RECT {
1508        left: frame_thickness,
1509        top: top_insets,
1510        right: frame_thickness,
1511        bottom: frame_thickness,
1512    }
1513}
1514
1515// there is some additional non-visible space when talking about window
1516// borders on Windows:
1517// - SM_CXSIZEFRAME: The resize handle.
1518// - SM_CXPADDEDBORDER: Additional border space that isn't part of the resize handle.
1519fn get_frame_thickness(dpi: u32) -> i32 {
1520    let resize_frame_thickness = unsafe { GetSystemMetricsForDpi(SM_CXSIZEFRAME, dpi) };
1521    let padding_thickness = unsafe { GetSystemMetricsForDpi(SM_CXPADDEDBORDER, dpi) };
1522    resize_frame_thickness + padding_thickness
1523}
1524
1525fn notify_frame_changed(handle: HWND) {
1526    unsafe {
1527        SetWindowPos(
1528            handle,
1529            None,
1530            0,
1531            0,
1532            0,
1533            0,
1534            SWP_FRAMECHANGED
1535                | SWP_NOACTIVATE
1536                | SWP_NOCOPYBITS
1537                | SWP_NOMOVE
1538                | SWP_NOOWNERZORDER
1539                | SWP_NOREPOSITION
1540                | SWP_NOSENDCHANGING
1541                | SWP_NOSIZE
1542                | SWP_NOZORDER,
1543        )
1544        .log_err();
1545    }
1546}