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;
  28pub(crate) const WM_GPUI_GPU_DEVICE_LOST: u32 = WM_USER + 7;
  29
  30const SIZE_MOVE_LOOP_TIMER_ID: usize = 1;
  31const AUTO_HIDE_TASKBAR_THICKNESS_PX: i32 = 1;
  32
  33impl WindowsWindowInner {
  34    pub(crate) fn handle_msg(
  35        self: &Rc<Self>,
  36        handle: HWND,
  37        msg: u32,
  38        wparam: WPARAM,
  39        lparam: LPARAM,
  40    ) -> LRESULT {
  41        let handled = match msg {
  42            WM_ACTIVATE => self.handle_activate_msg(wparam),
  43            WM_CREATE => self.handle_create_msg(handle),
  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            // Treat double click as a second single click, since we track the double clicks ourselves.
  61            // If you don't interact with any elements, this will fall through to the windows default
  62            // behavior of toggling whether the window is maximized.
  63            WM_NCLBUTTONDBLCLK | WM_NCLBUTTONDOWN => {
  64                self.handle_nc_mouse_down_msg(handle, MouseButton::Left, wparam, lparam)
  65            }
  66            WM_NCRBUTTONDOWN => {
  67                self.handle_nc_mouse_down_msg(handle, MouseButton::Right, wparam, lparam)
  68            }
  69            WM_NCMBUTTONDOWN => {
  70                self.handle_nc_mouse_down_msg(handle, MouseButton::Middle, wparam, lparam)
  71            }
  72            WM_NCLBUTTONUP => {
  73                self.handle_nc_mouse_up_msg(handle, MouseButton::Left, wparam, lparam)
  74            }
  75            WM_NCRBUTTONUP => {
  76                self.handle_nc_mouse_up_msg(handle, MouseButton::Right, wparam, lparam)
  77            }
  78            WM_NCMBUTTONUP => {
  79                self.handle_nc_mouse_up_msg(handle, MouseButton::Middle, wparam, lparam)
  80            }
  81            WM_LBUTTONDOWN => self.handle_mouse_down_msg(handle, MouseButton::Left, lparam),
  82            WM_RBUTTONDOWN => self.handle_mouse_down_msg(handle, MouseButton::Right, lparam),
  83            WM_MBUTTONDOWN => self.handle_mouse_down_msg(handle, MouseButton::Middle, lparam),
  84            WM_XBUTTONDOWN => {
  85                self.handle_xbutton_msg(handle, wparam, lparam, Self::handle_mouse_down_msg)
  86            }
  87            WM_LBUTTONUP => self.handle_mouse_up_msg(handle, MouseButton::Left, lparam),
  88            WM_RBUTTONUP => self.handle_mouse_up_msg(handle, MouseButton::Right, lparam),
  89            WM_MBUTTONUP => self.handle_mouse_up_msg(handle, MouseButton::Middle, lparam),
  90            WM_XBUTTONUP => {
  91                self.handle_xbutton_msg(handle, wparam, lparam, Self::handle_mouse_up_msg)
  92            }
  93            WM_MOUSEWHEEL => self.handle_mouse_wheel_msg(handle, wparam, lparam),
  94            WM_MOUSEHWHEEL => self.handle_mouse_horizontal_wheel_msg(handle, wparam, lparam),
  95            WM_SYSKEYDOWN => self.handle_syskeydown_msg(handle, wparam, lparam),
  96            WM_SYSKEYUP => self.handle_syskeyup_msg(handle, wparam, lparam),
  97            WM_SYSCOMMAND => self.handle_system_command(wparam),
  98            WM_KEYDOWN => self.handle_keydown_msg(handle, wparam, lparam),
  99            WM_KEYUP => self.handle_keyup_msg(handle, wparam, lparam),
 100            WM_CHAR => self.handle_char_msg(wparam),
 101            WM_DEADCHAR => self.handle_dead_char_msg(wparam),
 102            WM_IME_STARTCOMPOSITION => self.handle_ime_position(handle),
 103            WM_IME_COMPOSITION => self.handle_ime_composition(handle, lparam),
 104            WM_SETCURSOR => self.handle_set_cursor(handle, lparam),
 105            WM_SETTINGCHANGE => self.handle_system_settings_changed(handle, wparam, lparam),
 106            WM_INPUTLANGCHANGE => self.handle_input_language_changed(),
 107            WM_SHOWWINDOW => self.handle_window_visibility_changed(handle, wparam),
 108            WM_GPUI_CURSOR_STYLE_CHANGED => self.handle_cursor_changed(lparam),
 109            WM_GPUI_FORCE_UPDATE_WINDOW => self.draw_window(handle, true),
 110            WM_GPUI_GPU_DEVICE_LOST => self.handle_device_lost(lparam),
 111            _ => None,
 112        };
 113        if let Some(n) = handled {
 114            LRESULT(n)
 115        } else {
 116            unsafe { DefWindowProcW(handle, msg, wparam, lparam) }
 117        }
 118    }
 119
 120    fn handle_move_msg(&self, handle: HWND, lparam: LPARAM) -> Option<isize> {
 121        let mut lock = self.state.borrow_mut();
 122        let origin = logical_point(
 123            lparam.signed_loword() as f32,
 124            lparam.signed_hiword() as f32,
 125            lock.scale_factor,
 126        );
 127        lock.origin = origin;
 128        let size = lock.logical_size;
 129        let center_x = origin.x.0 + size.width.0 / 2.;
 130        let center_y = origin.y.0 + size.height.0 / 2.;
 131        let monitor_bounds = lock.display.bounds();
 132        if center_x < monitor_bounds.left().0
 133            || center_x > monitor_bounds.right().0
 134            || center_y < monitor_bounds.top().0
 135            || center_y > monitor_bounds.bottom().0
 136        {
 137            // center of the window may have moved to another monitor
 138            let monitor = unsafe { MonitorFromWindow(handle, MONITOR_DEFAULTTONULL) };
 139            // minimize the window can trigger this event too, in this case,
 140            // monitor is invalid, we do nothing.
 141            if !monitor.is_invalid() && lock.display.handle != monitor {
 142                // we will get the same monitor if we only have one
 143                lock.display = WindowsDisplay::new_with_handle(monitor);
 144            }
 145        }
 146        if let Some(mut callback) = lock.callbacks.moved.take() {
 147            drop(lock);
 148            callback();
 149            self.state.borrow_mut().callbacks.moved = Some(callback);
 150        }
 151        Some(0)
 152    }
 153
 154    fn handle_get_min_max_info_msg(&self, lparam: LPARAM) -> Option<isize> {
 155        let lock = self.state.borrow();
 156        let min_size = lock.min_size?;
 157        let scale_factor = lock.scale_factor;
 158        let boarder_offset = lock.border_offset;
 159        drop(lock);
 160        unsafe {
 161            let minmax_info = &mut *(lparam.0 as *mut MINMAXINFO);
 162            minmax_info.ptMinTrackSize.x =
 163                min_size.width.scale(scale_factor).0 as i32 + boarder_offset.width_offset;
 164            minmax_info.ptMinTrackSize.y =
 165                min_size.height.scale(scale_factor).0 as i32 + boarder_offset.height_offset;
 166        }
 167        Some(0)
 168    }
 169
 170    fn handle_size_msg(&self, wparam: WPARAM, lparam: LPARAM) -> Option<isize> {
 171        let mut lock = self.state.borrow_mut();
 172
 173        // Don't resize the renderer when the window is minimized, but record that it was minimized so
 174        // that on restore the swap chain can be recreated via `update_drawable_size_even_if_unchanged`.
 175        if wparam.0 == SIZE_MINIMIZED as usize {
 176            lock.restore_from_minimized = lock.callbacks.request_frame.take();
 177            return Some(0);
 178        }
 179
 180        let width = lparam.loword().max(1) as i32;
 181        let height = lparam.hiword().max(1) as i32;
 182        let new_size = size(DevicePixels(width), DevicePixels(height));
 183
 184        let scale_factor = lock.scale_factor;
 185        let mut should_resize_renderer = false;
 186        if lock.restore_from_minimized.is_some() {
 187            lock.callbacks.request_frame = lock.restore_from_minimized.take();
 188        } else {
 189            should_resize_renderer = true;
 190        }
 191        drop(lock);
 192
 193        self.handle_size_change(new_size, scale_factor, should_resize_renderer);
 194        Some(0)
 195    }
 196
 197    fn handle_size_change(
 198        &self,
 199        device_size: Size<DevicePixels>,
 200        scale_factor: f32,
 201        should_resize_renderer: bool,
 202    ) {
 203        let new_logical_size = device_size.to_pixels(scale_factor);
 204        let mut lock = self.state.borrow_mut();
 205        lock.logical_size = new_logical_size;
 206        if should_resize_renderer {
 207            lock.renderer.resize(device_size).log_err();
 208        }
 209        if let Some(mut callback) = lock.callbacks.resize.take() {
 210            drop(lock);
 211            callback(new_logical_size, scale_factor);
 212            self.state.borrow_mut().callbacks.resize = Some(callback);
 213        }
 214    }
 215
 216    fn handle_size_move_loop(&self, handle: HWND) -> Option<isize> {
 217        unsafe {
 218            let ret = SetTimer(
 219                Some(handle),
 220                SIZE_MOVE_LOOP_TIMER_ID,
 221                USER_TIMER_MINIMUM,
 222                None,
 223            );
 224            if ret == 0 {
 225                log::error!(
 226                    "unable to create timer: {}",
 227                    std::io::Error::last_os_error()
 228                );
 229            }
 230        }
 231        None
 232    }
 233
 234    fn handle_size_move_loop_exit(&self, handle: HWND) -> Option<isize> {
 235        unsafe {
 236            KillTimer(Some(handle), SIZE_MOVE_LOOP_TIMER_ID).log_err();
 237        }
 238        None
 239    }
 240
 241    fn handle_timer_msg(&self, handle: HWND, wparam: WPARAM) -> Option<isize> {
 242        if wparam.0 == SIZE_MOVE_LOOP_TIMER_ID {
 243            for runnable in self.main_receiver.drain() {
 244                runnable.run();
 245            }
 246            self.handle_paint_msg(handle)
 247        } else {
 248            None
 249        }
 250    }
 251
 252    fn handle_paint_msg(&self, handle: HWND) -> Option<isize> {
 253        self.draw_window(handle, false)
 254    }
 255
 256    fn handle_close_msg(&self) -> Option<isize> {
 257        let mut callback = self.state.borrow_mut().callbacks.should_close.take()?;
 258        let should_close = callback();
 259        self.state.borrow_mut().callbacks.should_close = Some(callback);
 260        if should_close { None } else { Some(0) }
 261    }
 262
 263    fn handle_destroy_msg(&self, handle: HWND) -> Option<isize> {
 264        let callback = {
 265            let mut lock = self.state.borrow_mut();
 266            lock.callbacks.close.take()
 267        };
 268        if let Some(callback) = callback {
 269            callback();
 270        }
 271        unsafe {
 272            PostMessageW(
 273                Some(self.platform_window_handle),
 274                WM_GPUI_CLOSE_ONE_WINDOW,
 275                WPARAM(self.validation_number),
 276                LPARAM(handle.0 as isize),
 277            )
 278            .log_err();
 279        }
 280        Some(0)
 281    }
 282
 283    fn handle_mouse_move_msg(&self, handle: HWND, lparam: LPARAM, wparam: WPARAM) -> Option<isize> {
 284        self.start_tracking_mouse(handle, TME_LEAVE);
 285
 286        let mut lock = self.state.borrow_mut();
 287        let Some(mut func) = lock.callbacks.input.take() else {
 288            return Some(1);
 289        };
 290        let scale_factor = lock.scale_factor;
 291        drop(lock);
 292
 293        let pressed_button = match MODIFIERKEYS_FLAGS(wparam.loword() as u32) {
 294            flags if flags.contains(MK_LBUTTON) => Some(MouseButton::Left),
 295            flags if flags.contains(MK_RBUTTON) => Some(MouseButton::Right),
 296            flags if flags.contains(MK_MBUTTON) => Some(MouseButton::Middle),
 297            flags if flags.contains(MK_XBUTTON1) => {
 298                Some(MouseButton::Navigate(NavigationDirection::Back))
 299            }
 300            flags if flags.contains(MK_XBUTTON2) => {
 301                Some(MouseButton::Navigate(NavigationDirection::Forward))
 302            }
 303            _ => None,
 304        };
 305        let x = lparam.signed_loword() as f32;
 306        let y = lparam.signed_hiword() as f32;
 307        let input = PlatformInput::MouseMove(MouseMoveEvent {
 308            position: logical_point(x, y, scale_factor),
 309            pressed_button,
 310            modifiers: current_modifiers(),
 311        });
 312        let handled = !func(input).propagate;
 313        self.state.borrow_mut().callbacks.input = Some(func);
 314
 315        if handled { Some(0) } else { Some(1) }
 316    }
 317
 318    fn handle_mouse_leave_msg(&self) -> Option<isize> {
 319        let mut lock = self.state.borrow_mut();
 320        lock.hovered = false;
 321        if let Some(mut callback) = lock.callbacks.hovered_status_change.take() {
 322            drop(lock);
 323            callback(false);
 324            self.state.borrow_mut().callbacks.hovered_status_change = Some(callback);
 325        }
 326
 327        Some(0)
 328    }
 329
 330    fn handle_syskeydown_msg(&self, handle: HWND, wparam: WPARAM, lparam: LPARAM) -> Option<isize> {
 331        let mut lock = self.state.borrow_mut();
 332        let input = handle_key_event(handle, wparam, lparam, &mut lock, |keystroke| {
 333            PlatformInput::KeyDown(KeyDownEvent {
 334                keystroke,
 335                is_held: lparam.0 & (0x1 << 30) > 0,
 336            })
 337        })?;
 338        let mut func = lock.callbacks.input.take()?;
 339        drop(lock);
 340
 341        let handled = !func(input).propagate;
 342
 343        let mut lock = self.state.borrow_mut();
 344        lock.callbacks.input = Some(func);
 345
 346        if handled {
 347            lock.system_key_handled = true;
 348            Some(0)
 349        } else {
 350            // we need to call `DefWindowProcW`, or we will lose the system-wide `Alt+F4`, `Alt+{other keys}`
 351            // shortcuts.
 352            None
 353        }
 354    }
 355
 356    fn handle_syskeyup_msg(&self, handle: HWND, wparam: WPARAM, lparam: LPARAM) -> Option<isize> {
 357        let mut lock = self.state.borrow_mut();
 358        let input = handle_key_event(handle, wparam, lparam, &mut lock, |keystroke| {
 359            PlatformInput::KeyUp(KeyUpEvent { keystroke })
 360        })?;
 361        let mut func = lock.callbacks.input.take()?;
 362        drop(lock);
 363        func(input);
 364        self.state.borrow_mut().callbacks.input = Some(func);
 365
 366        // Always return 0 to indicate that the message was handled, so we could properly handle `ModifiersChanged` event.
 367        Some(0)
 368    }
 369
 370    // It's a known bug that you can't trigger `ctrl-shift-0`. See:
 371    // https://superuser.com/questions/1455762/ctrl-shift-number-key-combination-has-stopped-working-for-a-few-numbers
 372    fn handle_keydown_msg(&self, handle: HWND, wparam: WPARAM, lparam: LPARAM) -> Option<isize> {
 373        let mut lock = self.state.borrow_mut();
 374        let Some(input) = handle_key_event(handle, wparam, lparam, &mut lock, |keystroke| {
 375            PlatformInput::KeyDown(KeyDownEvent {
 376                keystroke,
 377                is_held: lparam.0 & (0x1 << 30) > 0,
 378            })
 379        }) else {
 380            return Some(1);
 381        };
 382        drop(lock);
 383
 384        let is_composing = self
 385            .with_input_handler(|input_handler| input_handler.marked_text_range())
 386            .flatten()
 387            .is_some();
 388        if is_composing {
 389            translate_message(handle, wparam, lparam);
 390            return Some(0);
 391        }
 392
 393        let Some(mut func) = self.state.borrow_mut().callbacks.input.take() else {
 394            return Some(1);
 395        };
 396
 397        let handled = !func(input).propagate;
 398
 399        self.state.borrow_mut().callbacks.input = Some(func);
 400
 401        if handled {
 402            Some(0)
 403        } else {
 404            translate_message(handle, wparam, lparam);
 405            Some(1)
 406        }
 407    }
 408
 409    fn handle_keyup_msg(&self, handle: HWND, wparam: WPARAM, lparam: LPARAM) -> Option<isize> {
 410        let mut lock = self.state.borrow_mut();
 411        let Some(input) = handle_key_event(handle, wparam, lparam, &mut lock, |keystroke| {
 412            PlatformInput::KeyUp(KeyUpEvent { keystroke })
 413        }) else {
 414            return Some(1);
 415        };
 416
 417        let Some(mut func) = lock.callbacks.input.take() else {
 418            return Some(1);
 419        };
 420        drop(lock);
 421
 422        let handled = !func(input).propagate;
 423        self.state.borrow_mut().callbacks.input = Some(func);
 424
 425        if handled { Some(0) } else { Some(1) }
 426    }
 427
 428    fn handle_char_msg(&self, wparam: WPARAM) -> Option<isize> {
 429        let input = self.parse_char_message(wparam)?;
 430        self.with_input_handler(|input_handler| {
 431            input_handler.replace_text_in_range(None, &input);
 432        });
 433
 434        Some(0)
 435    }
 436
 437    fn handle_dead_char_msg(&self, wparam: WPARAM) -> Option<isize> {
 438        let ch = char::from_u32(wparam.0 as u32)?.to_string();
 439        self.with_input_handler(|input_handler| {
 440            input_handler.replace_and_mark_text_in_range(None, &ch, None);
 441        });
 442        None
 443    }
 444
 445    fn handle_mouse_down_msg(
 446        &self,
 447        handle: HWND,
 448        button: MouseButton,
 449        lparam: LPARAM,
 450    ) -> Option<isize> {
 451        unsafe { SetCapture(handle) };
 452        let mut lock = self.state.borrow_mut();
 453        let Some(mut func) = lock.callbacks.input.take() else {
 454            return Some(1);
 455        };
 456        let x = lparam.signed_loword();
 457        let y = lparam.signed_hiword();
 458        let physical_point = point(DevicePixels(x as i32), DevicePixels(y as i32));
 459        let click_count = lock.click_state.update(button, physical_point);
 460        let scale_factor = lock.scale_factor;
 461        drop(lock);
 462
 463        let input = PlatformInput::MouseDown(MouseDownEvent {
 464            button,
 465            position: logical_point(x as f32, y as f32, scale_factor),
 466            modifiers: current_modifiers(),
 467            click_count,
 468            first_mouse: false,
 469        });
 470        let handled = !func(input).propagate;
 471        self.state.borrow_mut().callbacks.input = Some(func);
 472
 473        if handled { Some(0) } else { Some(1) }
 474    }
 475
 476    fn handle_mouse_up_msg(
 477        &self,
 478        _handle: HWND,
 479        button: MouseButton,
 480        lparam: LPARAM,
 481    ) -> Option<isize> {
 482        unsafe { ReleaseCapture().log_err() };
 483        let mut lock = self.state.borrow_mut();
 484        let Some(mut func) = lock.callbacks.input.take() else {
 485            return Some(1);
 486        };
 487        let x = lparam.signed_loword() as f32;
 488        let y = lparam.signed_hiword() as f32;
 489        let click_count = lock.click_state.current_count;
 490        let scale_factor = lock.scale_factor;
 491        drop(lock);
 492
 493        let input = PlatformInput::MouseUp(MouseUpEvent {
 494            button,
 495            position: logical_point(x, y, scale_factor),
 496            modifiers: current_modifiers(),
 497            click_count,
 498        });
 499        let handled = !func(input).propagate;
 500        self.state.borrow_mut().callbacks.input = Some(func);
 501
 502        if handled { Some(0) } else { Some(1) }
 503    }
 504
 505    fn handle_xbutton_msg(
 506        &self,
 507        handle: HWND,
 508        wparam: WPARAM,
 509        lparam: LPARAM,
 510        handler: impl Fn(&Self, HWND, MouseButton, LPARAM) -> Option<isize>,
 511    ) -> Option<isize> {
 512        let nav_dir = match wparam.hiword() {
 513            XBUTTON1 => NavigationDirection::Back,
 514            XBUTTON2 => NavigationDirection::Forward,
 515            _ => return Some(1),
 516        };
 517        handler(self, handle, MouseButton::Navigate(nav_dir), lparam)
 518    }
 519
 520    fn handle_mouse_wheel_msg(
 521        &self,
 522        handle: HWND,
 523        wparam: WPARAM,
 524        lparam: LPARAM,
 525    ) -> Option<isize> {
 526        let modifiers = current_modifiers();
 527        let mut lock = self.state.borrow_mut();
 528        let Some(mut func) = lock.callbacks.input.take() else {
 529            return Some(1);
 530        };
 531        let scale_factor = lock.scale_factor;
 532        let wheel_scroll_amount = match modifiers.shift {
 533            true => {
 534                self.system_settings
 535                    .borrow()
 536                    .mouse_wheel_settings
 537                    .wheel_scroll_chars
 538            }
 539            false => {
 540                self.system_settings
 541                    .borrow()
 542                    .mouse_wheel_settings
 543                    .wheel_scroll_lines
 544            }
 545        };
 546        drop(lock);
 547
 548        let wheel_distance =
 549            (wparam.signed_hiword() as f32 / WHEEL_DELTA as f32) * wheel_scroll_amount as f32;
 550        let mut cursor_point = POINT {
 551            x: lparam.signed_loword().into(),
 552            y: lparam.signed_hiword().into(),
 553        };
 554        unsafe { ScreenToClient(handle, &mut cursor_point).ok().log_err() };
 555        let input = PlatformInput::ScrollWheel(ScrollWheelEvent {
 556            position: logical_point(cursor_point.x as f32, cursor_point.y as f32, scale_factor),
 557            delta: ScrollDelta::Lines(match modifiers.shift {
 558                true => Point {
 559                    x: wheel_distance,
 560                    y: 0.0,
 561                },
 562                false => Point {
 563                    y: wheel_distance,
 564                    x: 0.0,
 565                },
 566            }),
 567            modifiers,
 568            touch_phase: TouchPhase::Moved,
 569        });
 570        let handled = !func(input).propagate;
 571        self.state.borrow_mut().callbacks.input = Some(func);
 572
 573        if handled { Some(0) } else { Some(1) }
 574    }
 575
 576    fn handle_mouse_horizontal_wheel_msg(
 577        &self,
 578        handle: HWND,
 579        wparam: WPARAM,
 580        lparam: LPARAM,
 581    ) -> Option<isize> {
 582        let mut lock = self.state.borrow_mut();
 583        let Some(mut func) = lock.callbacks.input.take() else {
 584            return Some(1);
 585        };
 586        let scale_factor = lock.scale_factor;
 587        let wheel_scroll_chars = self
 588            .system_settings
 589            .borrow()
 590            .mouse_wheel_settings
 591            .wheel_scroll_chars;
 592        drop(lock);
 593
 594        let wheel_distance =
 595            (-wparam.signed_hiword() as f32 / WHEEL_DELTA as f32) * wheel_scroll_chars as f32;
 596        let mut cursor_point = POINT {
 597            x: lparam.signed_loword().into(),
 598            y: lparam.signed_hiword().into(),
 599        };
 600        unsafe { ScreenToClient(handle, &mut cursor_point).ok().log_err() };
 601        let event = PlatformInput::ScrollWheel(ScrollWheelEvent {
 602            position: logical_point(cursor_point.x as f32, cursor_point.y as f32, scale_factor),
 603            delta: ScrollDelta::Lines(Point {
 604                x: wheel_distance,
 605                y: 0.0,
 606            }),
 607            modifiers: current_modifiers(),
 608            touch_phase: TouchPhase::Moved,
 609        });
 610        let handled = !func(event).propagate;
 611        self.state.borrow_mut().callbacks.input = Some(func);
 612
 613        if handled { Some(0) } else { Some(1) }
 614    }
 615
 616    fn retrieve_caret_position(&self) -> Option<POINT> {
 617        self.with_input_handler_and_scale_factor(|input_handler, scale_factor| {
 618            let caret_range = input_handler.selected_text_range(false)?;
 619            let caret_position = input_handler.bounds_for_range(caret_range.range)?;
 620            Some(POINT {
 621                // logical to physical
 622                x: (caret_position.origin.x.0 * scale_factor) as i32,
 623                y: (caret_position.origin.y.0 * scale_factor) as i32
 624                    + ((caret_position.size.height.0 * scale_factor) as i32 / 2),
 625            })
 626        })
 627    }
 628
 629    fn handle_ime_position(&self, handle: HWND) -> Option<isize> {
 630        unsafe {
 631            let ctx = ImmGetContext(handle);
 632
 633            let Some(caret_position) = self.retrieve_caret_position() else {
 634                return Some(0);
 635            };
 636            {
 637                let config = COMPOSITIONFORM {
 638                    dwStyle: CFS_POINT,
 639                    ptCurrentPos: caret_position,
 640                    ..Default::default()
 641                };
 642                ImmSetCompositionWindow(ctx, &config as _).ok().log_err();
 643            }
 644            {
 645                let config = CANDIDATEFORM {
 646                    dwStyle: CFS_CANDIDATEPOS,
 647                    ptCurrentPos: caret_position,
 648                    ..Default::default()
 649                };
 650                ImmSetCandidateWindow(ctx, &config as _).ok().log_err();
 651            }
 652            ImmReleaseContext(handle, ctx).ok().log_err();
 653            Some(0)
 654        }
 655    }
 656
 657    fn handle_ime_composition(&self, handle: HWND, lparam: LPARAM) -> Option<isize> {
 658        let ctx = unsafe { ImmGetContext(handle) };
 659        let result = self.handle_ime_composition_inner(ctx, lparam);
 660        unsafe { ImmReleaseContext(handle, ctx).ok().log_err() };
 661        result
 662    }
 663
 664    fn handle_ime_composition_inner(&self, ctx: HIMC, lparam: LPARAM) -> Option<isize> {
 665        let lparam = lparam.0 as u32;
 666        if lparam == 0 {
 667            // Japanese IME may send this message with lparam = 0, which indicates that
 668            // there is no composition string.
 669            self.with_input_handler(|input_handler| {
 670                input_handler.replace_text_in_range(None, "");
 671            })?;
 672            Some(0)
 673        } else {
 674            if lparam & GCS_COMPSTR.0 > 0 {
 675                let comp_string = parse_ime_composition_string(ctx, GCS_COMPSTR)?;
 676                let caret_pos =
 677                    (!comp_string.is_empty() && lparam & GCS_CURSORPOS.0 > 0).then(|| {
 678                        let pos = retrieve_composition_cursor_position(ctx);
 679                        pos..pos
 680                    });
 681                self.with_input_handler(|input_handler| {
 682                    input_handler.replace_and_mark_text_in_range(None, &comp_string, caret_pos);
 683                })?;
 684            }
 685            if lparam & GCS_RESULTSTR.0 > 0 {
 686                let comp_result = parse_ime_composition_string(ctx, GCS_RESULTSTR)?;
 687                self.with_input_handler(|input_handler| {
 688                    input_handler.replace_text_in_range(None, &comp_result);
 689                })?;
 690                return Some(0);
 691            }
 692
 693            // currently, we don't care other stuff
 694            None
 695        }
 696    }
 697
 698    /// SEE: https://learn.microsoft.com/en-us/windows/win32/winmsg/wm-nccalcsize
 699    fn handle_calc_client_size(
 700        &self,
 701        handle: HWND,
 702        wparam: WPARAM,
 703        lparam: LPARAM,
 704    ) -> Option<isize> {
 705        if !self.hide_title_bar || self.state.borrow().is_fullscreen() || wparam.0 == 0 {
 706            return None;
 707        }
 708
 709        let is_maximized = self.state.borrow().is_maximized();
 710        let insets = get_client_area_insets(handle, is_maximized, self.windows_version);
 711        // wparam is TRUE so lparam points to an NCCALCSIZE_PARAMS structure
 712        let mut params = lparam.0 as *mut NCCALCSIZE_PARAMS;
 713        let mut requested_client_rect = unsafe { &mut ((*params).rgrc) };
 714
 715        requested_client_rect[0].left += insets.left;
 716        requested_client_rect[0].top += insets.top;
 717        requested_client_rect[0].right -= insets.right;
 718        requested_client_rect[0].bottom -= insets.bottom;
 719
 720        // Fix auto hide taskbar not showing. This solution is based on the approach
 721        // used by Chrome. However, it may result in one row of pixels being obscured
 722        // in our client area. But as Chrome says, "there seems to be no better solution."
 723        if is_maximized
 724            && let Some(ref taskbar_position) =
 725                self.system_settings.borrow().auto_hide_taskbar_position
 726        {
 727            // For the auto-hide taskbar, adjust in by 1 pixel on taskbar edge,
 728            // so the window isn't treated as a "fullscreen app", which would cause
 729            // the taskbar to disappear.
 730            match taskbar_position {
 731                AutoHideTaskbarPosition::Left => {
 732                    requested_client_rect[0].left += AUTO_HIDE_TASKBAR_THICKNESS_PX
 733                }
 734                AutoHideTaskbarPosition::Top => {
 735                    requested_client_rect[0].top += AUTO_HIDE_TASKBAR_THICKNESS_PX
 736                }
 737                AutoHideTaskbarPosition::Right => {
 738                    requested_client_rect[0].right -= AUTO_HIDE_TASKBAR_THICKNESS_PX
 739                }
 740                AutoHideTaskbarPosition::Bottom => {
 741                    requested_client_rect[0].bottom -= AUTO_HIDE_TASKBAR_THICKNESS_PX
 742                }
 743            }
 744        }
 745
 746        Some(0)
 747    }
 748
 749    fn handle_activate_msg(self: &Rc<Self>, wparam: WPARAM) -> Option<isize> {
 750        let activated = wparam.loword() > 0;
 751        let this = self.clone();
 752        self.executor
 753            .spawn(async move {
 754                let mut lock = this.state.borrow_mut();
 755                if let Some(mut func) = lock.callbacks.active_status_change.take() {
 756                    drop(lock);
 757                    func(activated);
 758                    this.state.borrow_mut().callbacks.active_status_change = Some(func);
 759                }
 760            })
 761            .detach();
 762
 763        None
 764    }
 765
 766    fn handle_create_msg(&self, handle: HWND) -> Option<isize> {
 767        if self.hide_title_bar {
 768            notify_frame_changed(handle);
 769            Some(0)
 770        } else {
 771            None
 772        }
 773    }
 774
 775    fn handle_dpi_changed_msg(
 776        &self,
 777        handle: HWND,
 778        wparam: WPARAM,
 779        lparam: LPARAM,
 780    ) -> Option<isize> {
 781        let new_dpi = wparam.loword() as f32;
 782        let mut lock = self.state.borrow_mut();
 783        let is_maximized = lock.is_maximized();
 784        let new_scale_factor = new_dpi / USER_DEFAULT_SCREEN_DPI as f32;
 785        lock.scale_factor = new_scale_factor;
 786        lock.border_offset.update(handle).log_err();
 787        drop(lock);
 788
 789        let rect = unsafe { &*(lparam.0 as *const RECT) };
 790        let width = rect.right - rect.left;
 791        let height = rect.bottom - rect.top;
 792        // this will emit `WM_SIZE` and `WM_MOVE` right here
 793        // even before this function returns
 794        // the new size is handled in `WM_SIZE`
 795        unsafe {
 796            SetWindowPos(
 797                handle,
 798                None,
 799                rect.left,
 800                rect.top,
 801                width,
 802                height,
 803                SWP_NOZORDER | SWP_NOACTIVATE,
 804            )
 805            .context("unable to set window position after dpi has changed")
 806            .log_err();
 807        }
 808
 809        // When maximized, SetWindowPos doesn't send WM_SIZE, so we need to manually
 810        // update the size and call the resize callback
 811        if is_maximized {
 812            let device_size = size(DevicePixels(width), DevicePixels(height));
 813            self.handle_size_change(device_size, new_scale_factor, true);
 814        }
 815
 816        Some(0)
 817    }
 818
 819    /// The following conditions will trigger this event:
 820    /// 1. The monitor on which the window is located goes offline or changes resolution.
 821    /// 2. Another monitor goes offline, is plugged in, or changes resolution.
 822    ///
 823    /// In either case, the window will only receive information from the monitor on which
 824    /// it is located.
 825    ///
 826    /// For example, in the case of condition 2, where the monitor on which the window is
 827    /// located has actually changed nothing, it will still receive this event.
 828    fn handle_display_change_msg(&self, handle: HWND) -> Option<isize> {
 829        // NOTE:
 830        // Even the `lParam` holds the resolution of the screen, we just ignore it.
 831        // Because WM_DPICHANGED, WM_MOVE, WM_SIZE will come first, window reposition and resize
 832        // are handled there.
 833        // So we only care about if monitor is disconnected.
 834        let previous_monitor = self.state.borrow().display;
 835        if WindowsDisplay::is_connected(previous_monitor.handle) {
 836            // we are fine, other display changed
 837            return None;
 838        }
 839        // display disconnected
 840        // in this case, the OS will move our window to another monitor, and minimize it.
 841        // we deminimize the window and query the monitor after moving
 842        unsafe {
 843            let _ = ShowWindow(handle, SW_SHOWNORMAL);
 844        };
 845        let new_monitor = unsafe { MonitorFromWindow(handle, MONITOR_DEFAULTTONULL) };
 846        // all monitors disconnected
 847        if new_monitor.is_invalid() {
 848            log::error!("No monitor detected!");
 849            return None;
 850        }
 851        let new_display = WindowsDisplay::new_with_handle(new_monitor);
 852        self.state.borrow_mut().display = new_display;
 853        Some(0)
 854    }
 855
 856    fn handle_hit_test_msg(
 857        &self,
 858        handle: HWND,
 859        msg: u32,
 860        wparam: WPARAM,
 861        lparam: LPARAM,
 862    ) -> Option<isize> {
 863        if !self.is_movable || self.state.borrow().is_fullscreen() {
 864            return None;
 865        }
 866
 867        let mut lock = self.state.borrow_mut();
 868        if let Some(mut callback) = lock.callbacks.hit_test_window_control.take() {
 869            drop(lock);
 870            let area = callback();
 871            self.state.borrow_mut().callbacks.hit_test_window_control = Some(callback);
 872            if let Some(area) = area {
 873                return match area {
 874                    WindowControlArea::Drag => Some(HTCAPTION as _),
 875                    WindowControlArea::Close => Some(HTCLOSE as _),
 876                    WindowControlArea::Max => Some(HTMAXBUTTON as _),
 877                    WindowControlArea::Min => Some(HTMINBUTTON as _),
 878                };
 879            }
 880        } else {
 881            drop(lock);
 882        }
 883
 884        if !self.hide_title_bar {
 885            // If the OS draws the title bar, we don't need to handle hit test messages.
 886            return None;
 887        }
 888
 889        // default handler for resize areas
 890        let hit = unsafe { DefWindowProcW(handle, msg, wparam, lparam) };
 891        if matches!(
 892            hit.0 as u32,
 893            HTNOWHERE
 894                | HTRIGHT
 895                | HTLEFT
 896                | HTTOPLEFT
 897                | HTTOP
 898                | HTTOPRIGHT
 899                | HTBOTTOMRIGHT
 900                | HTBOTTOM
 901                | HTBOTTOMLEFT
 902        ) {
 903            return Some(hit.0);
 904        }
 905
 906        if self.state.borrow().is_fullscreen() {
 907            return Some(HTCLIENT as _);
 908        }
 909
 910        let dpi = unsafe { GetDpiForWindow(handle) };
 911        let frame_y = unsafe { GetSystemMetricsForDpi(SM_CYFRAME, dpi) };
 912
 913        let mut cursor_point = POINT {
 914            x: lparam.signed_loword().into(),
 915            y: lparam.signed_hiword().into(),
 916        };
 917        unsafe { ScreenToClient(handle, &mut cursor_point).ok().log_err() };
 918        if !self.state.borrow().is_maximized() && cursor_point.y >= 0 && cursor_point.y <= frame_y {
 919            return Some(HTTOP as _);
 920        }
 921
 922        Some(HTCLIENT as _)
 923    }
 924
 925    fn handle_nc_mouse_move_msg(&self, handle: HWND, lparam: LPARAM) -> Option<isize> {
 926        self.start_tracking_mouse(handle, TME_LEAVE | TME_NONCLIENT);
 927
 928        let mut lock = self.state.borrow_mut();
 929        let mut func = lock.callbacks.input.take()?;
 930        let scale_factor = lock.scale_factor;
 931        drop(lock);
 932
 933        let mut cursor_point = POINT {
 934            x: lparam.signed_loword().into(),
 935            y: lparam.signed_hiword().into(),
 936        };
 937        unsafe { ScreenToClient(handle, &mut cursor_point).ok().log_err() };
 938        let input = PlatformInput::MouseMove(MouseMoveEvent {
 939            position: logical_point(cursor_point.x as f32, cursor_point.y as f32, scale_factor),
 940            pressed_button: None,
 941            modifiers: current_modifiers(),
 942        });
 943        let handled = !func(input).propagate;
 944        self.state.borrow_mut().callbacks.input = Some(func);
 945
 946        if handled { Some(0) } else { None }
 947    }
 948
 949    fn handle_nc_mouse_down_msg(
 950        &self,
 951        handle: HWND,
 952        button: MouseButton,
 953        wparam: WPARAM,
 954        lparam: LPARAM,
 955    ) -> Option<isize> {
 956        let mut lock = self.state.borrow_mut();
 957        if let Some(mut func) = lock.callbacks.input.take() {
 958            let scale_factor = lock.scale_factor;
 959            let mut cursor_point = POINT {
 960                x: lparam.signed_loword().into(),
 961                y: lparam.signed_hiword().into(),
 962            };
 963            unsafe { ScreenToClient(handle, &mut cursor_point).ok().log_err() };
 964            let physical_point = point(DevicePixels(cursor_point.x), DevicePixels(cursor_point.y));
 965            let click_count = lock.click_state.update(button, physical_point);
 966            drop(lock);
 967
 968            let input = PlatformInput::MouseDown(MouseDownEvent {
 969                button,
 970                position: logical_point(cursor_point.x as f32, cursor_point.y as f32, scale_factor),
 971                modifiers: current_modifiers(),
 972                click_count,
 973                first_mouse: false,
 974            });
 975            let result = func(input);
 976            let handled = !result.propagate || result.default_prevented;
 977            self.state.borrow_mut().callbacks.input = Some(func);
 978
 979            if handled {
 980                return Some(0);
 981            }
 982        } else {
 983            drop(lock);
 984        };
 985
 986        // Since these are handled in handle_nc_mouse_up_msg we must prevent the default window proc
 987        if button == MouseButton::Left {
 988            match wparam.0 as u32 {
 989                HTMINBUTTON => self.state.borrow_mut().nc_button_pressed = Some(HTMINBUTTON),
 990                HTMAXBUTTON => self.state.borrow_mut().nc_button_pressed = Some(HTMAXBUTTON),
 991                HTCLOSE => self.state.borrow_mut().nc_button_pressed = Some(HTCLOSE),
 992                _ => return None,
 993            };
 994            Some(0)
 995        } else {
 996            None
 997        }
 998    }
 999
1000    fn handle_nc_mouse_up_msg(
1001        &self,
1002        handle: HWND,
1003        button: MouseButton,
1004        wparam: WPARAM,
1005        lparam: LPARAM,
1006    ) -> Option<isize> {
1007        let mut lock = self.state.borrow_mut();
1008        if let Some(mut func) = lock.callbacks.input.take() {
1009            let scale_factor = lock.scale_factor;
1010            drop(lock);
1011
1012            let mut cursor_point = POINT {
1013                x: lparam.signed_loword().into(),
1014                y: lparam.signed_hiword().into(),
1015            };
1016            unsafe { ScreenToClient(handle, &mut cursor_point).ok().log_err() };
1017            let input = PlatformInput::MouseUp(MouseUpEvent {
1018                button,
1019                position: logical_point(cursor_point.x as f32, cursor_point.y as f32, scale_factor),
1020                modifiers: current_modifiers(),
1021                click_count: 1,
1022            });
1023            let handled = !func(input).propagate;
1024            self.state.borrow_mut().callbacks.input = Some(func);
1025
1026            if handled {
1027                return Some(0);
1028            }
1029        } else {
1030            drop(lock);
1031        }
1032
1033        let last_pressed = self.state.borrow_mut().nc_button_pressed.take();
1034        if button == MouseButton::Left
1035            && let Some(last_pressed) = last_pressed
1036        {
1037            let handled = match (wparam.0 as u32, last_pressed) {
1038                (HTMINBUTTON, HTMINBUTTON) => {
1039                    unsafe { ShowWindowAsync(handle, SW_MINIMIZE).ok().log_err() };
1040                    true
1041                }
1042                (HTMAXBUTTON, HTMAXBUTTON) => {
1043                    if self.state.borrow().is_maximized() {
1044                        unsafe { ShowWindowAsync(handle, SW_NORMAL).ok().log_err() };
1045                    } else {
1046                        unsafe { ShowWindowAsync(handle, SW_MAXIMIZE).ok().log_err() };
1047                    }
1048                    true
1049                }
1050                (HTCLOSE, HTCLOSE) => {
1051                    unsafe {
1052                        PostMessageW(Some(handle), WM_CLOSE, WPARAM::default(), LPARAM::default())
1053                            .log_err()
1054                    };
1055                    true
1056                }
1057                _ => false,
1058            };
1059            if handled {
1060                return Some(0);
1061            }
1062        }
1063
1064        None
1065    }
1066
1067    fn handle_cursor_changed(&self, lparam: LPARAM) -> Option<isize> {
1068        let mut state = self.state.borrow_mut();
1069        let had_cursor = state.current_cursor.is_some();
1070
1071        state.current_cursor = if lparam.0 == 0 {
1072            None
1073        } else {
1074            Some(HCURSOR(lparam.0 as _))
1075        };
1076
1077        if had_cursor != state.current_cursor.is_some() {
1078            unsafe { SetCursor(state.current_cursor) };
1079        }
1080
1081        Some(0)
1082    }
1083
1084    fn handle_set_cursor(&self, handle: HWND, lparam: LPARAM) -> Option<isize> {
1085        if unsafe { !IsWindowEnabled(handle).as_bool() }
1086            || matches!(
1087                lparam.loword() as u32,
1088                HTLEFT
1089                    | HTRIGHT
1090                    | HTTOP
1091                    | HTTOPLEFT
1092                    | HTTOPRIGHT
1093                    | HTBOTTOM
1094                    | HTBOTTOMLEFT
1095                    | HTBOTTOMRIGHT
1096            )
1097        {
1098            return None;
1099        }
1100        unsafe {
1101            SetCursor(self.state.borrow().current_cursor);
1102        };
1103        Some(1)
1104    }
1105
1106    fn handle_system_settings_changed(
1107        &self,
1108        handle: HWND,
1109        wparam: WPARAM,
1110        lparam: LPARAM,
1111    ) -> Option<isize> {
1112        if wparam.0 != 0 {
1113            let mut lock = self.state.borrow_mut();
1114            let display = lock.display;
1115            lock.click_state.system_update(wparam.0);
1116            lock.border_offset.update(handle).log_err();
1117            // system settings may emit a window message which wants to take the refcell lock, so drop it
1118            drop(lock);
1119            self.system_settings.borrow_mut().update(display, wparam.0);
1120        } else {
1121            self.handle_system_theme_changed(handle, lparam)?;
1122        };
1123        // Force to trigger WM_NCCALCSIZE event to ensure that we handle auto hide
1124        // taskbar correctly.
1125        notify_frame_changed(handle);
1126
1127        Some(0)
1128    }
1129
1130    fn handle_system_command(&self, wparam: WPARAM) -> Option<isize> {
1131        if wparam.0 == SC_KEYMENU as usize {
1132            let mut lock = self.state.borrow_mut();
1133            if lock.system_key_handled {
1134                lock.system_key_handled = false;
1135                return Some(0);
1136            }
1137        }
1138        None
1139    }
1140
1141    fn handle_system_theme_changed(&self, handle: HWND, lparam: LPARAM) -> Option<isize> {
1142        // lParam is a pointer to a string that indicates the area containing the system parameter
1143        // that was changed.
1144        let parameter = PCWSTR::from_raw(lparam.0 as _);
1145        if unsafe { !parameter.is_null() && !parameter.is_empty() }
1146            && let Some(parameter_string) = unsafe { parameter.to_string() }.log_err()
1147        {
1148            log::info!("System settings changed: {}", parameter_string);
1149            if parameter_string.as_str() == "ImmersiveColorSet" {
1150                let new_appearance = system_appearance()
1151                    .context("unable to get system appearance when handling ImmersiveColorSet")
1152                    .log_err()?;
1153                let mut lock = self.state.borrow_mut();
1154                if new_appearance != lock.appearance {
1155                    lock.appearance = new_appearance;
1156                    let mut callback = lock.callbacks.appearance_changed.take()?;
1157                    drop(lock);
1158                    callback();
1159                    self.state.borrow_mut().callbacks.appearance_changed = Some(callback);
1160                    configure_dwm_dark_mode(handle, new_appearance);
1161                }
1162            }
1163        }
1164        Some(0)
1165    }
1166
1167    fn handle_input_language_changed(&self) -> Option<isize> {
1168        unsafe {
1169            PostMessageW(
1170                Some(self.platform_window_handle),
1171                WM_GPUI_KEYBOARD_LAYOUT_CHANGED,
1172                WPARAM(self.validation_number),
1173                LPARAM(0),
1174            )
1175            .log_err();
1176        }
1177        Some(0)
1178    }
1179
1180    fn handle_window_visibility_changed(&self, handle: HWND, wparam: WPARAM) -> Option<isize> {
1181        if wparam.0 == 1 {
1182            self.draw_window(handle, false);
1183        }
1184        None
1185    }
1186
1187    fn handle_device_lost(&self, lparam: LPARAM) -> Option<isize> {
1188        let mut lock = self.state.borrow_mut();
1189        let devices = lparam.0 as *const DirectXDevices;
1190        let devices = unsafe { &*devices };
1191        lock.renderer.handle_device_lost(&devices);
1192        Some(0)
1193    }
1194
1195    #[inline]
1196    fn draw_window(&self, handle: HWND, force_render: bool) -> Option<isize> {
1197        let mut request_frame = self.state.borrow_mut().callbacks.request_frame.take()?;
1198        request_frame(RequestFrameOptions {
1199            require_presentation: false,
1200            force_render,
1201        });
1202        self.state.borrow_mut().callbacks.request_frame = Some(request_frame);
1203        unsafe { ValidateRect(Some(handle), None).ok().log_err() };
1204        Some(0)
1205    }
1206
1207    #[inline]
1208    fn parse_char_message(&self, wparam: WPARAM) -> Option<String> {
1209        let code_point = wparam.loword();
1210        let mut lock = self.state.borrow_mut();
1211        // https://www.unicode.org/versions/Unicode16.0.0/core-spec/chapter-3/#G2630
1212        match code_point {
1213            0xD800..=0xDBFF => {
1214                // High surrogate, wait for low surrogate
1215                lock.pending_surrogate = Some(code_point);
1216                None
1217            }
1218            0xDC00..=0xDFFF => {
1219                if let Some(high_surrogate) = lock.pending_surrogate.take() {
1220                    // Low surrogate, combine with pending high surrogate
1221                    String::from_utf16(&[high_surrogate, code_point]).ok()
1222                } else {
1223                    // Invalid low surrogate without a preceding high surrogate
1224                    log::warn!(
1225                        "Received low surrogate without a preceding high surrogate: {code_point:x}"
1226                    );
1227                    None
1228                }
1229            }
1230            _ => {
1231                lock.pending_surrogate = None;
1232                char::from_u32(code_point as u32)
1233                    .filter(|c| !c.is_control())
1234                    .map(|c| c.to_string())
1235            }
1236        }
1237    }
1238
1239    fn start_tracking_mouse(&self, handle: HWND, flags: TRACKMOUSEEVENT_FLAGS) {
1240        let mut lock = self.state.borrow_mut();
1241        if !lock.hovered {
1242            lock.hovered = true;
1243            unsafe {
1244                TrackMouseEvent(&mut TRACKMOUSEEVENT {
1245                    cbSize: std::mem::size_of::<TRACKMOUSEEVENT>() as u32,
1246                    dwFlags: flags,
1247                    hwndTrack: handle,
1248                    dwHoverTime: HOVER_DEFAULT,
1249                })
1250                .log_err()
1251            };
1252            if let Some(mut callback) = lock.callbacks.hovered_status_change.take() {
1253                drop(lock);
1254                callback(true);
1255                self.state.borrow_mut().callbacks.hovered_status_change = Some(callback);
1256            }
1257        }
1258    }
1259
1260    fn with_input_handler<F, R>(&self, f: F) -> Option<R>
1261    where
1262        F: FnOnce(&mut PlatformInputHandler) -> R,
1263    {
1264        let mut input_handler = self.state.borrow_mut().input_handler.take()?;
1265        let result = f(&mut input_handler);
1266        self.state.borrow_mut().input_handler = Some(input_handler);
1267        Some(result)
1268    }
1269
1270    fn with_input_handler_and_scale_factor<F, R>(&self, f: F) -> Option<R>
1271    where
1272        F: FnOnce(&mut PlatformInputHandler, f32) -> Option<R>,
1273    {
1274        let mut lock = self.state.borrow_mut();
1275        let mut input_handler = lock.input_handler.take()?;
1276        let scale_factor = lock.scale_factor;
1277        drop(lock);
1278        let result = f(&mut input_handler, scale_factor);
1279        self.state.borrow_mut().input_handler = Some(input_handler);
1280        result
1281    }
1282}
1283
1284#[inline]
1285fn translate_message(handle: HWND, wparam: WPARAM, lparam: LPARAM) {
1286    let msg = MSG {
1287        hwnd: handle,
1288        message: WM_KEYDOWN,
1289        wParam: wparam,
1290        lParam: lparam,
1291        // It seems like leaving the following two parameters empty doesn't break key events, they still work as expected.
1292        // But if any bugs pop up after this PR, this is probably the place to look first.
1293        time: 0,
1294        pt: POINT::default(),
1295    };
1296    unsafe { TranslateMessage(&msg).ok().log_err() };
1297}
1298
1299fn handle_key_event<F>(
1300    handle: HWND,
1301    wparam: WPARAM,
1302    lparam: LPARAM,
1303    state: &mut WindowsWindowState,
1304    f: F,
1305) -> Option<PlatformInput>
1306where
1307    F: FnOnce(Keystroke) -> PlatformInput,
1308{
1309    let virtual_key = VIRTUAL_KEY(wparam.loword());
1310    let mut modifiers = current_modifiers();
1311
1312    match virtual_key {
1313        VK_SHIFT | VK_CONTROL | VK_MENU | VK_LWIN | VK_RWIN => {
1314            if state
1315                .last_reported_modifiers
1316                .is_some_and(|prev_modifiers| prev_modifiers == modifiers)
1317            {
1318                return None;
1319            }
1320            state.last_reported_modifiers = Some(modifiers);
1321            Some(PlatformInput::ModifiersChanged(ModifiersChangedEvent {
1322                modifiers,
1323                capslock: current_capslock(),
1324            }))
1325        }
1326        VK_PACKET => {
1327            translate_message(handle, wparam, lparam);
1328            None
1329        }
1330        VK_CAPITAL => {
1331            let capslock = current_capslock();
1332            if state
1333                .last_reported_capslock
1334                .is_some_and(|prev_capslock| prev_capslock == capslock)
1335            {
1336                return None;
1337            }
1338            state.last_reported_capslock = Some(capslock);
1339            Some(PlatformInput::ModifiersChanged(ModifiersChangedEvent {
1340                modifiers,
1341                capslock,
1342            }))
1343        }
1344        vkey => {
1345            let vkey = if vkey == VK_PROCESSKEY {
1346                VIRTUAL_KEY(unsafe { ImmGetVirtualKey(handle) } as u16)
1347            } else {
1348                vkey
1349            };
1350            let keystroke = parse_normal_key(vkey, lparam, modifiers)?;
1351            Some(f(keystroke))
1352        }
1353    }
1354}
1355
1356fn parse_immutable(vkey: VIRTUAL_KEY) -> Option<String> {
1357    Some(
1358        match vkey {
1359            VK_SPACE => "space",
1360            VK_BACK => "backspace",
1361            VK_RETURN => "enter",
1362            VK_TAB => "tab",
1363            VK_UP => "up",
1364            VK_DOWN => "down",
1365            VK_RIGHT => "right",
1366            VK_LEFT => "left",
1367            VK_HOME => "home",
1368            VK_END => "end",
1369            VK_PRIOR => "pageup",
1370            VK_NEXT => "pagedown",
1371            VK_BROWSER_BACK => "back",
1372            VK_BROWSER_FORWARD => "forward",
1373            VK_ESCAPE => "escape",
1374            VK_INSERT => "insert",
1375            VK_DELETE => "delete",
1376            VK_APPS => "menu",
1377            VK_F1 => "f1",
1378            VK_F2 => "f2",
1379            VK_F3 => "f3",
1380            VK_F4 => "f4",
1381            VK_F5 => "f5",
1382            VK_F6 => "f6",
1383            VK_F7 => "f7",
1384            VK_F8 => "f8",
1385            VK_F9 => "f9",
1386            VK_F10 => "f10",
1387            VK_F11 => "f11",
1388            VK_F12 => "f12",
1389            VK_F13 => "f13",
1390            VK_F14 => "f14",
1391            VK_F15 => "f15",
1392            VK_F16 => "f16",
1393            VK_F17 => "f17",
1394            VK_F18 => "f18",
1395            VK_F19 => "f19",
1396            VK_F20 => "f20",
1397            VK_F21 => "f21",
1398            VK_F22 => "f22",
1399            VK_F23 => "f23",
1400            VK_F24 => "f24",
1401            _ => return None,
1402        }
1403        .to_string(),
1404    )
1405}
1406
1407fn parse_normal_key(
1408    vkey: VIRTUAL_KEY,
1409    lparam: LPARAM,
1410    mut modifiers: Modifiers,
1411) -> Option<Keystroke> {
1412    let mut key_char = None;
1413    let key = parse_immutable(vkey).or_else(|| {
1414        let scan_code = lparam.hiword() & 0xFF;
1415        key_char = generate_key_char(
1416            vkey,
1417            scan_code as u32,
1418            modifiers.control,
1419            modifiers.shift,
1420            modifiers.alt,
1421        );
1422        get_keystroke_key(vkey, scan_code as u32, &mut modifiers)
1423    })?;
1424    Some(Keystroke {
1425        modifiers,
1426        key,
1427        key_char,
1428    })
1429}
1430
1431fn parse_ime_composition_string(ctx: HIMC, comp_type: IME_COMPOSITION_STRING) -> Option<String> {
1432    unsafe {
1433        let string_len = ImmGetCompositionStringW(ctx, comp_type, None, 0);
1434        if string_len >= 0 {
1435            let mut buffer = vec![0u8; string_len as usize + 2];
1436            ImmGetCompositionStringW(
1437                ctx,
1438                comp_type,
1439                Some(buffer.as_mut_ptr() as _),
1440                string_len as _,
1441            );
1442            let wstring = std::slice::from_raw_parts::<u16>(
1443                buffer.as_mut_ptr().cast::<u16>(),
1444                string_len as usize / 2,
1445            );
1446            Some(String::from_utf16_lossy(wstring))
1447        } else {
1448            None
1449        }
1450    }
1451}
1452
1453#[inline]
1454fn retrieve_composition_cursor_position(ctx: HIMC) -> usize {
1455    unsafe { ImmGetCompositionStringW(ctx, GCS_CURSORPOS, None, 0) as usize }
1456}
1457
1458#[inline]
1459fn is_virtual_key_pressed(vkey: VIRTUAL_KEY) -> bool {
1460    unsafe { GetKeyState(vkey.0 as i32) < 0 }
1461}
1462
1463#[inline]
1464pub(crate) fn current_modifiers() -> Modifiers {
1465    let altgr = is_virtual_key_pressed(VK_RMENU) && is_virtual_key_pressed(VK_LCONTROL);
1466
1467    Modifiers {
1468        control: is_virtual_key_pressed(VK_CONTROL) && !altgr,
1469        alt: is_virtual_key_pressed(VK_MENU) && !altgr,
1470        shift: is_virtual_key_pressed(VK_SHIFT),
1471        platform: is_virtual_key_pressed(VK_LWIN) || is_virtual_key_pressed(VK_RWIN),
1472        function: false,
1473    }
1474}
1475
1476#[inline]
1477pub(crate) fn current_capslock() -> Capslock {
1478    let on = unsafe { GetKeyState(VK_CAPITAL.0 as i32) & 1 } > 0;
1479    Capslock { on }
1480}
1481
1482fn get_client_area_insets(
1483    handle: HWND,
1484    is_maximized: bool,
1485    windows_version: WindowsVersion,
1486) -> RECT {
1487    // For maximized windows, Windows outdents the window rect from the screen's client rect
1488    // by `frame_thickness` on each edge, meaning `insets` must contain `frame_thickness`
1489    // on all sides (including the top) to avoid the client area extending onto adjacent
1490    // monitors.
1491    //
1492    // For non-maximized windows, things become complicated:
1493    //
1494    // - On Windows 10
1495    // The top inset must be zero, since if there is any nonclient area, Windows will draw
1496    // a full native titlebar outside the client area. (This doesn't occur in the maximized
1497    // case.)
1498    //
1499    // - On Windows 11
1500    // The top inset is calculated using an empirical formula that I derived through various
1501    // tests. Without this, the top 1-2 rows of pixels in our window would be obscured.
1502    let dpi = unsafe { GetDpiForWindow(handle) };
1503    let frame_thickness = get_frame_thickness(dpi);
1504    let top_insets = if is_maximized {
1505        frame_thickness
1506    } else {
1507        match windows_version {
1508            WindowsVersion::Win10 => 0,
1509            WindowsVersion::Win11 => (dpi as f32 / USER_DEFAULT_SCREEN_DPI as f32).round() as i32,
1510        }
1511    };
1512    RECT {
1513        left: frame_thickness,
1514        top: top_insets,
1515        right: frame_thickness,
1516        bottom: frame_thickness,
1517    }
1518}
1519
1520// there is some additional non-visible space when talking about window
1521// borders on Windows:
1522// - SM_CXSIZEFRAME: The resize handle.
1523// - SM_CXPADDEDBORDER: Additional border space that isn't part of the resize handle.
1524fn get_frame_thickness(dpi: u32) -> i32 {
1525    let resize_frame_thickness = unsafe { GetSystemMetricsForDpi(SM_CXSIZEFRAME, dpi) };
1526    let padding_thickness = unsafe { GetSystemMetricsForDpi(SM_CXPADDEDBORDER, dpi) };
1527    resize_frame_thickness + padding_thickness
1528}
1529
1530fn notify_frame_changed(handle: HWND) {
1531    unsafe {
1532        SetWindowPos(
1533            handle,
1534            None,
1535            0,
1536            0,
1537            0,
1538            0,
1539            SWP_FRAMECHANGED
1540                | SWP_NOACTIVATE
1541                | SWP_NOCOPYBITS
1542                | SWP_NOMOVE
1543                | SWP_NOOWNERZORDER
1544                | SWP_NOREPOSITION
1545                | SWP_NOSENDCHANGING
1546                | SWP_NOSIZE
1547                | SWP_NOZORDER,
1548        )
1549        .log_err();
1550    }
1551}