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 => lock.system_settings.mouse_wheel_settings.wheel_scroll_chars,
 534            false => lock.system_settings.mouse_wheel_settings.wheel_scroll_lines,
 535        };
 536        drop(lock);
 537
 538        let wheel_distance =
 539            (wparam.signed_hiword() as f32 / WHEEL_DELTA as f32) * wheel_scroll_amount as f32;
 540        let mut cursor_point = POINT {
 541            x: lparam.signed_loword().into(),
 542            y: lparam.signed_hiword().into(),
 543        };
 544        unsafe { ScreenToClient(handle, &mut cursor_point).ok().log_err() };
 545        let input = PlatformInput::ScrollWheel(ScrollWheelEvent {
 546            position: logical_point(cursor_point.x as f32, cursor_point.y as f32, scale_factor),
 547            delta: ScrollDelta::Lines(match modifiers.shift {
 548                true => Point {
 549                    x: wheel_distance,
 550                    y: 0.0,
 551                },
 552                false => Point {
 553                    y: wheel_distance,
 554                    x: 0.0,
 555                },
 556            }),
 557            modifiers,
 558            touch_phase: TouchPhase::Moved,
 559        });
 560        let handled = !func(input).propagate;
 561        self.state.borrow_mut().callbacks.input = Some(func);
 562
 563        if handled { Some(0) } else { Some(1) }
 564    }
 565
 566    fn handle_mouse_horizontal_wheel_msg(
 567        &self,
 568        handle: HWND,
 569        wparam: WPARAM,
 570        lparam: LPARAM,
 571    ) -> Option<isize> {
 572        let mut lock = self.state.borrow_mut();
 573        let Some(mut func) = lock.callbacks.input.take() else {
 574            return Some(1);
 575        };
 576        let scale_factor = lock.scale_factor;
 577        let wheel_scroll_chars = lock.system_settings.mouse_wheel_settings.wheel_scroll_chars;
 578        drop(lock);
 579
 580        let wheel_distance =
 581            (-wparam.signed_hiword() as f32 / WHEEL_DELTA as f32) * wheel_scroll_chars as f32;
 582        let mut cursor_point = POINT {
 583            x: lparam.signed_loword().into(),
 584            y: lparam.signed_hiword().into(),
 585        };
 586        unsafe { ScreenToClient(handle, &mut cursor_point).ok().log_err() };
 587        let event = PlatformInput::ScrollWheel(ScrollWheelEvent {
 588            position: logical_point(cursor_point.x as f32, cursor_point.y as f32, scale_factor),
 589            delta: ScrollDelta::Lines(Point {
 590                x: wheel_distance,
 591                y: 0.0,
 592            }),
 593            modifiers: current_modifiers(),
 594            touch_phase: TouchPhase::Moved,
 595        });
 596        let handled = !func(event).propagate;
 597        self.state.borrow_mut().callbacks.input = Some(func);
 598
 599        if handled { Some(0) } else { Some(1) }
 600    }
 601
 602    fn retrieve_caret_position(&self) -> Option<POINT> {
 603        self.with_input_handler_and_scale_factor(|input_handler, scale_factor| {
 604            let caret_range = input_handler.selected_text_range(false)?;
 605            let caret_position = input_handler.bounds_for_range(caret_range.range)?;
 606            Some(POINT {
 607                // logical to physical
 608                x: (caret_position.origin.x.0 * scale_factor) as i32,
 609                y: (caret_position.origin.y.0 * scale_factor) as i32
 610                    + ((caret_position.size.height.0 * scale_factor) as i32 / 2),
 611            })
 612        })
 613    }
 614
 615    fn handle_ime_position(&self, handle: HWND) -> Option<isize> {
 616        unsafe {
 617            let ctx = ImmGetContext(handle);
 618
 619            let Some(caret_position) = self.retrieve_caret_position() else {
 620                return Some(0);
 621            };
 622            {
 623                let config = COMPOSITIONFORM {
 624                    dwStyle: CFS_POINT,
 625                    ptCurrentPos: caret_position,
 626                    ..Default::default()
 627                };
 628                ImmSetCompositionWindow(ctx, &config as _).ok().log_err();
 629            }
 630            {
 631                let config = CANDIDATEFORM {
 632                    dwStyle: CFS_CANDIDATEPOS,
 633                    ptCurrentPos: caret_position,
 634                    ..Default::default()
 635                };
 636                ImmSetCandidateWindow(ctx, &config as _).ok().log_err();
 637            }
 638            ImmReleaseContext(handle, ctx).ok().log_err();
 639            Some(0)
 640        }
 641    }
 642
 643    fn handle_ime_composition(&self, handle: HWND, lparam: LPARAM) -> Option<isize> {
 644        let ctx = unsafe { ImmGetContext(handle) };
 645        let result = self.handle_ime_composition_inner(ctx, lparam);
 646        unsafe { ImmReleaseContext(handle, ctx).ok().log_err() };
 647        result
 648    }
 649
 650    fn handle_ime_composition_inner(&self, ctx: HIMC, lparam: LPARAM) -> Option<isize> {
 651        let lparam = lparam.0 as u32;
 652        if lparam == 0 {
 653            // Japanese IME may send this message with lparam = 0, which indicates that
 654            // there is no composition string.
 655            self.with_input_handler(|input_handler| {
 656                input_handler.replace_text_in_range(None, "");
 657            })?;
 658            Some(0)
 659        } else {
 660            if lparam & GCS_COMPSTR.0 > 0 {
 661                let comp_string = parse_ime_composition_string(ctx, GCS_COMPSTR)?;
 662                let caret_pos =
 663                    (!comp_string.is_empty() && lparam & GCS_CURSORPOS.0 > 0).then(|| {
 664                        let pos = retrieve_composition_cursor_position(ctx);
 665                        pos..pos
 666                    });
 667                self.with_input_handler(|input_handler| {
 668                    input_handler.replace_and_mark_text_in_range(None, &comp_string, caret_pos);
 669                })?;
 670            }
 671            if lparam & GCS_RESULTSTR.0 > 0 {
 672                let comp_result = parse_ime_composition_string(ctx, GCS_RESULTSTR)?;
 673                self.with_input_handler(|input_handler| {
 674                    input_handler.replace_text_in_range(None, &comp_result);
 675                })?;
 676                return Some(0);
 677            }
 678
 679            // currently, we don't care other stuff
 680            None
 681        }
 682    }
 683
 684    /// SEE: https://learn.microsoft.com/en-us/windows/win32/winmsg/wm-nccalcsize
 685    fn handle_calc_client_size(
 686        &self,
 687        handle: HWND,
 688        wparam: WPARAM,
 689        lparam: LPARAM,
 690    ) -> Option<isize> {
 691        if !self.hide_title_bar || self.state.borrow().is_fullscreen() || wparam.0 == 0 {
 692            return None;
 693        }
 694
 695        let is_maximized = self.state.borrow().is_maximized();
 696        let insets = get_client_area_insets(handle, is_maximized, self.windows_version);
 697        // wparam is TRUE so lparam points to an NCCALCSIZE_PARAMS structure
 698        let mut params = lparam.0 as *mut NCCALCSIZE_PARAMS;
 699        let mut requested_client_rect = unsafe { &mut ((*params).rgrc) };
 700
 701        requested_client_rect[0].left += insets.left;
 702        requested_client_rect[0].top += insets.top;
 703        requested_client_rect[0].right -= insets.right;
 704        requested_client_rect[0].bottom -= insets.bottom;
 705
 706        // Fix auto hide taskbar not showing. This solution is based on the approach
 707        // used by Chrome. However, it may result in one row of pixels being obscured
 708        // in our client area. But as Chrome says, "there seems to be no better solution."
 709        if is_maximized
 710            && let Some(ref taskbar_position) = self
 711                .state
 712                .borrow()
 713                .system_settings
 714                .auto_hide_taskbar_position
 715        {
 716            // For the auto-hide taskbar, adjust in by 1 pixel on taskbar edge,
 717            // so the window isn't treated as a "fullscreen app", which would cause
 718            // the taskbar to disappear.
 719            match taskbar_position {
 720                AutoHideTaskbarPosition::Left => {
 721                    requested_client_rect[0].left += AUTO_HIDE_TASKBAR_THICKNESS_PX
 722                }
 723                AutoHideTaskbarPosition::Top => {
 724                    requested_client_rect[0].top += AUTO_HIDE_TASKBAR_THICKNESS_PX
 725                }
 726                AutoHideTaskbarPosition::Right => {
 727                    requested_client_rect[0].right -= AUTO_HIDE_TASKBAR_THICKNESS_PX
 728                }
 729                AutoHideTaskbarPosition::Bottom => {
 730                    requested_client_rect[0].bottom -= AUTO_HIDE_TASKBAR_THICKNESS_PX
 731                }
 732            }
 733        }
 734
 735        Some(0)
 736    }
 737
 738    fn handle_activate_msg(self: &Rc<Self>, wparam: WPARAM) -> Option<isize> {
 739        let activated = wparam.loword() > 0;
 740        let this = self.clone();
 741        self.executor
 742            .spawn(async move {
 743                let mut lock = this.state.borrow_mut();
 744                if let Some(mut func) = lock.callbacks.active_status_change.take() {
 745                    drop(lock);
 746                    func(activated);
 747                    this.state.borrow_mut().callbacks.active_status_change = Some(func);
 748                }
 749            })
 750            .detach();
 751
 752        None
 753    }
 754
 755    fn handle_create_msg(&self, handle: HWND) -> Option<isize> {
 756        if self.hide_title_bar {
 757            notify_frame_changed(handle);
 758            Some(0)
 759        } else {
 760            None
 761        }
 762    }
 763
 764    fn handle_dpi_changed_msg(
 765        &self,
 766        handle: HWND,
 767        wparam: WPARAM,
 768        lparam: LPARAM,
 769    ) -> Option<isize> {
 770        let new_dpi = wparam.loword() as f32;
 771        let mut lock = self.state.borrow_mut();
 772        let is_maximized = lock.is_maximized();
 773        let new_scale_factor = new_dpi / USER_DEFAULT_SCREEN_DPI as f32;
 774        lock.scale_factor = new_scale_factor;
 775        lock.border_offset.update(handle).log_err();
 776        drop(lock);
 777
 778        let rect = unsafe { &*(lparam.0 as *const RECT) };
 779        let width = rect.right - rect.left;
 780        let height = rect.bottom - rect.top;
 781        // this will emit `WM_SIZE` and `WM_MOVE` right here
 782        // even before this function returns
 783        // the new size is handled in `WM_SIZE`
 784        unsafe {
 785            SetWindowPos(
 786                handle,
 787                None,
 788                rect.left,
 789                rect.top,
 790                width,
 791                height,
 792                SWP_NOZORDER | SWP_NOACTIVATE,
 793            )
 794            .context("unable to set window position after dpi has changed")
 795            .log_err();
 796        }
 797
 798        // When maximized, SetWindowPos doesn't send WM_SIZE, so we need to manually
 799        // update the size and call the resize callback
 800        if is_maximized {
 801            let device_size = size(DevicePixels(width), DevicePixels(height));
 802            self.handle_size_change(device_size, new_scale_factor, true);
 803        }
 804
 805        Some(0)
 806    }
 807
 808    /// The following conditions will trigger this event:
 809    /// 1. The monitor on which the window is located goes offline or changes resolution.
 810    /// 2. Another monitor goes offline, is plugged in, or changes resolution.
 811    ///
 812    /// In either case, the window will only receive information from the monitor on which
 813    /// it is located.
 814    ///
 815    /// For example, in the case of condition 2, where the monitor on which the window is
 816    /// located has actually changed nothing, it will still receive this event.
 817    fn handle_display_change_msg(&self, handle: HWND) -> Option<isize> {
 818        // NOTE:
 819        // Even the `lParam` holds the resolution of the screen, we just ignore it.
 820        // Because WM_DPICHANGED, WM_MOVE, WM_SIZE will come first, window reposition and resize
 821        // are handled there.
 822        // So we only care about if monitor is disconnected.
 823        let previous_monitor = self.state.borrow().display;
 824        if WindowsDisplay::is_connected(previous_monitor.handle) {
 825            // we are fine, other display changed
 826            return None;
 827        }
 828        // display disconnected
 829        // in this case, the OS will move our window to another monitor, and minimize it.
 830        // we deminimize the window and query the monitor after moving
 831        unsafe {
 832            let _ = ShowWindow(handle, SW_SHOWNORMAL);
 833        };
 834        let new_monitor = unsafe { MonitorFromWindow(handle, MONITOR_DEFAULTTONULL) };
 835        // all monitors disconnected
 836        if new_monitor.is_invalid() {
 837            log::error!("No monitor detected!");
 838            return None;
 839        }
 840        let new_display = WindowsDisplay::new_with_handle(new_monitor);
 841        self.state.borrow_mut().display = new_display;
 842        Some(0)
 843    }
 844
 845    fn handle_hit_test_msg(
 846        &self,
 847        handle: HWND,
 848        msg: u32,
 849        wparam: WPARAM,
 850        lparam: LPARAM,
 851    ) -> Option<isize> {
 852        if !self.is_movable || self.state.borrow().is_fullscreen() {
 853            return None;
 854        }
 855
 856        let mut lock = self.state.borrow_mut();
 857        if let Some(mut callback) = lock.callbacks.hit_test_window_control.take() {
 858            drop(lock);
 859            let area = callback();
 860            self.state.borrow_mut().callbacks.hit_test_window_control = Some(callback);
 861            if let Some(area) = area {
 862                return match area {
 863                    WindowControlArea::Drag => Some(HTCAPTION as _),
 864                    WindowControlArea::Close => Some(HTCLOSE as _),
 865                    WindowControlArea::Max => Some(HTMAXBUTTON as _),
 866                    WindowControlArea::Min => Some(HTMINBUTTON as _),
 867                };
 868            }
 869        } else {
 870            drop(lock);
 871        }
 872
 873        if !self.hide_title_bar {
 874            // If the OS draws the title bar, we don't need to handle hit test messages.
 875            return None;
 876        }
 877
 878        // default handler for resize areas
 879        let hit = unsafe { DefWindowProcW(handle, msg, wparam, lparam) };
 880        if matches!(
 881            hit.0 as u32,
 882            HTNOWHERE
 883                | HTRIGHT
 884                | HTLEFT
 885                | HTTOPLEFT
 886                | HTTOP
 887                | HTTOPRIGHT
 888                | HTBOTTOMRIGHT
 889                | HTBOTTOM
 890                | HTBOTTOMLEFT
 891        ) {
 892            return Some(hit.0);
 893        }
 894
 895        if self.state.borrow().is_fullscreen() {
 896            return Some(HTCLIENT as _);
 897        }
 898
 899        let dpi = unsafe { GetDpiForWindow(handle) };
 900        let frame_y = unsafe { GetSystemMetricsForDpi(SM_CYFRAME, dpi) };
 901
 902        let mut cursor_point = POINT {
 903            x: lparam.signed_loword().into(),
 904            y: lparam.signed_hiword().into(),
 905        };
 906        unsafe { ScreenToClient(handle, &mut cursor_point).ok().log_err() };
 907        if !self.state.borrow().is_maximized() && cursor_point.y >= 0 && cursor_point.y <= frame_y {
 908            return Some(HTTOP as _);
 909        }
 910
 911        Some(HTCLIENT as _)
 912    }
 913
 914    fn handle_nc_mouse_move_msg(&self, handle: HWND, lparam: LPARAM) -> Option<isize> {
 915        self.start_tracking_mouse(handle, TME_LEAVE | TME_NONCLIENT);
 916
 917        let mut lock = self.state.borrow_mut();
 918        let mut func = lock.callbacks.input.take()?;
 919        let scale_factor = lock.scale_factor;
 920        drop(lock);
 921
 922        let mut cursor_point = POINT {
 923            x: lparam.signed_loword().into(),
 924            y: lparam.signed_hiword().into(),
 925        };
 926        unsafe { ScreenToClient(handle, &mut cursor_point).ok().log_err() };
 927        let input = PlatformInput::MouseMove(MouseMoveEvent {
 928            position: logical_point(cursor_point.x as f32, cursor_point.y as f32, scale_factor),
 929            pressed_button: None,
 930            modifiers: current_modifiers(),
 931        });
 932        let handled = !func(input).propagate;
 933        self.state.borrow_mut().callbacks.input = Some(func);
 934
 935        if handled { Some(0) } else { None }
 936    }
 937
 938    fn handle_nc_mouse_down_msg(
 939        &self,
 940        handle: HWND,
 941        button: MouseButton,
 942        wparam: WPARAM,
 943        lparam: LPARAM,
 944    ) -> Option<isize> {
 945        let mut lock = self.state.borrow_mut();
 946        if let Some(mut func) = lock.callbacks.input.take() {
 947            let scale_factor = lock.scale_factor;
 948            let mut cursor_point = POINT {
 949                x: lparam.signed_loword().into(),
 950                y: lparam.signed_hiword().into(),
 951            };
 952            unsafe { ScreenToClient(handle, &mut cursor_point).ok().log_err() };
 953            let physical_point = point(DevicePixels(cursor_point.x), DevicePixels(cursor_point.y));
 954            let click_count = lock.click_state.update(button, physical_point);
 955            drop(lock);
 956
 957            let input = PlatformInput::MouseDown(MouseDownEvent {
 958                button,
 959                position: logical_point(cursor_point.x as f32, cursor_point.y as f32, scale_factor),
 960                modifiers: current_modifiers(),
 961                click_count,
 962                first_mouse: false,
 963            });
 964            let result = func(input);
 965            let handled = !result.propagate || result.default_prevented;
 966            self.state.borrow_mut().callbacks.input = Some(func);
 967
 968            if handled {
 969                return Some(0);
 970            }
 971        } else {
 972            drop(lock);
 973        };
 974
 975        // Since these are handled in handle_nc_mouse_up_msg we must prevent the default window proc
 976        if button == MouseButton::Left {
 977            match wparam.0 as u32 {
 978                HTMINBUTTON => self.state.borrow_mut().nc_button_pressed = Some(HTMINBUTTON),
 979                HTMAXBUTTON => self.state.borrow_mut().nc_button_pressed = Some(HTMAXBUTTON),
 980                HTCLOSE => self.state.borrow_mut().nc_button_pressed = Some(HTCLOSE),
 981                _ => return None,
 982            };
 983            Some(0)
 984        } else {
 985            None
 986        }
 987    }
 988
 989    fn handle_nc_mouse_up_msg(
 990        &self,
 991        handle: HWND,
 992        button: MouseButton,
 993        wparam: WPARAM,
 994        lparam: LPARAM,
 995    ) -> Option<isize> {
 996        let mut lock = self.state.borrow_mut();
 997        if let Some(mut func) = lock.callbacks.input.take() {
 998            let scale_factor = lock.scale_factor;
 999            drop(lock);
1000
1001            let mut cursor_point = POINT {
1002                x: lparam.signed_loword().into(),
1003                y: lparam.signed_hiword().into(),
1004            };
1005            unsafe { ScreenToClient(handle, &mut cursor_point).ok().log_err() };
1006            let input = PlatformInput::MouseUp(MouseUpEvent {
1007                button,
1008                position: logical_point(cursor_point.x as f32, cursor_point.y as f32, scale_factor),
1009                modifiers: current_modifiers(),
1010                click_count: 1,
1011            });
1012            let handled = !func(input).propagate;
1013            self.state.borrow_mut().callbacks.input = Some(func);
1014
1015            if handled {
1016                return Some(0);
1017            }
1018        } else {
1019            drop(lock);
1020        }
1021
1022        let last_pressed = self.state.borrow_mut().nc_button_pressed.take();
1023        if button == MouseButton::Left
1024            && let Some(last_pressed) = last_pressed
1025        {
1026            let handled = match (wparam.0 as u32, last_pressed) {
1027                (HTMINBUTTON, HTMINBUTTON) => {
1028                    unsafe { ShowWindowAsync(handle, SW_MINIMIZE).ok().log_err() };
1029                    true
1030                }
1031                (HTMAXBUTTON, HTMAXBUTTON) => {
1032                    if self.state.borrow().is_maximized() {
1033                        unsafe { ShowWindowAsync(handle, SW_NORMAL).ok().log_err() };
1034                    } else {
1035                        unsafe { ShowWindowAsync(handle, SW_MAXIMIZE).ok().log_err() };
1036                    }
1037                    true
1038                }
1039                (HTCLOSE, HTCLOSE) => {
1040                    unsafe {
1041                        PostMessageW(Some(handle), WM_CLOSE, WPARAM::default(), LPARAM::default())
1042                            .log_err()
1043                    };
1044                    true
1045                }
1046                _ => false,
1047            };
1048            if handled {
1049                return Some(0);
1050            }
1051        }
1052
1053        None
1054    }
1055
1056    fn handle_cursor_changed(&self, lparam: LPARAM) -> Option<isize> {
1057        let mut state = self.state.borrow_mut();
1058        let had_cursor = state.current_cursor.is_some();
1059
1060        state.current_cursor = if lparam.0 == 0 {
1061            None
1062        } else {
1063            Some(HCURSOR(lparam.0 as _))
1064        };
1065
1066        if had_cursor != state.current_cursor.is_some() {
1067            unsafe { SetCursor(state.current_cursor) };
1068        }
1069
1070        Some(0)
1071    }
1072
1073    fn handle_set_cursor(&self, handle: HWND, lparam: LPARAM) -> Option<isize> {
1074        if unsafe { !IsWindowEnabled(handle).as_bool() }
1075            || matches!(
1076                lparam.loword() as u32,
1077                HTLEFT
1078                    | HTRIGHT
1079                    | HTTOP
1080                    | HTTOPLEFT
1081                    | HTTOPRIGHT
1082                    | HTBOTTOM
1083                    | HTBOTTOMLEFT
1084                    | HTBOTTOMRIGHT
1085            )
1086        {
1087            return None;
1088        }
1089        unsafe {
1090            SetCursor(self.state.borrow().current_cursor);
1091        };
1092        Some(1)
1093    }
1094
1095    fn handle_system_settings_changed(
1096        &self,
1097        handle: HWND,
1098        wparam: WPARAM,
1099        lparam: LPARAM,
1100    ) -> Option<isize> {
1101        if wparam.0 != 0 {
1102            let mut lock = self.state.borrow_mut();
1103            let display = lock.display;
1104            lock.system_settings.update(display, wparam.0);
1105            lock.click_state.system_update(wparam.0);
1106            lock.border_offset.update(handle).log_err();
1107        } else {
1108            self.handle_system_theme_changed(handle, lparam)?;
1109        };
1110        // Force to trigger WM_NCCALCSIZE event to ensure that we handle auto hide
1111        // taskbar correctly.
1112        notify_frame_changed(handle);
1113
1114        Some(0)
1115    }
1116
1117    fn handle_system_command(&self, wparam: WPARAM) -> Option<isize> {
1118        if wparam.0 == SC_KEYMENU as usize {
1119            let mut lock = self.state.borrow_mut();
1120            if lock.system_key_handled {
1121                lock.system_key_handled = false;
1122                return Some(0);
1123            }
1124        }
1125        None
1126    }
1127
1128    fn handle_system_theme_changed(&self, handle: HWND, lparam: LPARAM) -> Option<isize> {
1129        // lParam is a pointer to a string that indicates the area containing the system parameter
1130        // that was changed.
1131        let parameter = PCWSTR::from_raw(lparam.0 as _);
1132        if unsafe { !parameter.is_null() && !parameter.is_empty() }
1133            && let Some(parameter_string) = unsafe { parameter.to_string() }.log_err()
1134        {
1135            log::info!("System settings changed: {}", parameter_string);
1136            if parameter_string.as_str() == "ImmersiveColorSet" {
1137                let new_appearance = system_appearance()
1138                    .context("unable to get system appearance when handling ImmersiveColorSet")
1139                    .log_err()?;
1140                let mut lock = self.state.borrow_mut();
1141                if new_appearance != lock.appearance {
1142                    lock.appearance = new_appearance;
1143                    let mut callback = lock.callbacks.appearance_changed.take()?;
1144                    drop(lock);
1145                    callback();
1146                    self.state.borrow_mut().callbacks.appearance_changed = Some(callback);
1147                    configure_dwm_dark_mode(handle, new_appearance);
1148                }
1149            }
1150        }
1151        Some(0)
1152    }
1153
1154    fn handle_input_language_changed(&self) -> Option<isize> {
1155        unsafe {
1156            PostMessageW(
1157                Some(self.platform_window_handle),
1158                WM_GPUI_KEYBOARD_LAYOUT_CHANGED,
1159                WPARAM(self.validation_number),
1160                LPARAM(0),
1161            )
1162            .log_err();
1163        }
1164        Some(0)
1165    }
1166
1167    fn handle_window_visibility_changed(&self, handle: HWND, wparam: WPARAM) -> Option<isize> {
1168        if wparam.0 == 1 {
1169            self.draw_window(handle, false);
1170        }
1171        None
1172    }
1173
1174    fn handle_device_lost(&self, lparam: LPARAM) -> Option<isize> {
1175        let mut lock = self.state.borrow_mut();
1176        let devices = lparam.0 as *const DirectXDevices;
1177        let devices = unsafe { &*devices };
1178        lock.renderer.handle_device_lost(&devices);
1179        Some(0)
1180    }
1181
1182    #[inline]
1183    fn draw_window(&self, handle: HWND, force_render: bool) -> Option<isize> {
1184        let mut request_frame = self.state.borrow_mut().callbacks.request_frame.take()?;
1185        request_frame(RequestFrameOptions {
1186            require_presentation: false,
1187            force_render,
1188        });
1189        self.state.borrow_mut().callbacks.request_frame = Some(request_frame);
1190        unsafe { ValidateRect(Some(handle), None).ok().log_err() };
1191        Some(0)
1192    }
1193
1194    #[inline]
1195    fn parse_char_message(&self, wparam: WPARAM) -> Option<String> {
1196        let code_point = wparam.loword();
1197        let mut lock = self.state.borrow_mut();
1198        // https://www.unicode.org/versions/Unicode16.0.0/core-spec/chapter-3/#G2630
1199        match code_point {
1200            0xD800..=0xDBFF => {
1201                // High surrogate, wait for low surrogate
1202                lock.pending_surrogate = Some(code_point);
1203                None
1204            }
1205            0xDC00..=0xDFFF => {
1206                if let Some(high_surrogate) = lock.pending_surrogate.take() {
1207                    // Low surrogate, combine with pending high surrogate
1208                    String::from_utf16(&[high_surrogate, code_point]).ok()
1209                } else {
1210                    // Invalid low surrogate without a preceding high surrogate
1211                    log::warn!(
1212                        "Received low surrogate without a preceding high surrogate: {code_point:x}"
1213                    );
1214                    None
1215                }
1216            }
1217            _ => {
1218                lock.pending_surrogate = None;
1219                char::from_u32(code_point as u32)
1220                    .filter(|c| !c.is_control())
1221                    .map(|c| c.to_string())
1222            }
1223        }
1224    }
1225
1226    fn start_tracking_mouse(&self, handle: HWND, flags: TRACKMOUSEEVENT_FLAGS) {
1227        let mut lock = self.state.borrow_mut();
1228        if !lock.hovered {
1229            lock.hovered = true;
1230            unsafe {
1231                TrackMouseEvent(&mut TRACKMOUSEEVENT {
1232                    cbSize: std::mem::size_of::<TRACKMOUSEEVENT>() as u32,
1233                    dwFlags: flags,
1234                    hwndTrack: handle,
1235                    dwHoverTime: HOVER_DEFAULT,
1236                })
1237                .log_err()
1238            };
1239            if let Some(mut callback) = lock.callbacks.hovered_status_change.take() {
1240                drop(lock);
1241                callback(true);
1242                self.state.borrow_mut().callbacks.hovered_status_change = Some(callback);
1243            }
1244        }
1245    }
1246
1247    fn with_input_handler<F, R>(&self, f: F) -> Option<R>
1248    where
1249        F: FnOnce(&mut PlatformInputHandler) -> R,
1250    {
1251        let mut input_handler = self.state.borrow_mut().input_handler.take()?;
1252        let result = f(&mut input_handler);
1253        self.state.borrow_mut().input_handler = Some(input_handler);
1254        Some(result)
1255    }
1256
1257    fn with_input_handler_and_scale_factor<F, R>(&self, f: F) -> Option<R>
1258    where
1259        F: FnOnce(&mut PlatformInputHandler, f32) -> Option<R>,
1260    {
1261        let mut lock = self.state.borrow_mut();
1262        let mut input_handler = lock.input_handler.take()?;
1263        let scale_factor = lock.scale_factor;
1264        drop(lock);
1265        let result = f(&mut input_handler, scale_factor);
1266        self.state.borrow_mut().input_handler = Some(input_handler);
1267        result
1268    }
1269}
1270
1271#[inline]
1272fn translate_message(handle: HWND, wparam: WPARAM, lparam: LPARAM) {
1273    let msg = MSG {
1274        hwnd: handle,
1275        message: WM_KEYDOWN,
1276        wParam: wparam,
1277        lParam: lparam,
1278        // It seems like leaving the following two parameters empty doesn't break key events, they still work as expected.
1279        // But if any bugs pop up after this PR, this is probably the place to look first.
1280        time: 0,
1281        pt: POINT::default(),
1282    };
1283    unsafe { TranslateMessage(&msg).ok().log_err() };
1284}
1285
1286fn handle_key_event<F>(
1287    handle: HWND,
1288    wparam: WPARAM,
1289    lparam: LPARAM,
1290    state: &mut WindowsWindowState,
1291    f: F,
1292) -> Option<PlatformInput>
1293where
1294    F: FnOnce(Keystroke) -> PlatformInput,
1295{
1296    let virtual_key = VIRTUAL_KEY(wparam.loword());
1297    let mut modifiers = current_modifiers();
1298
1299    match virtual_key {
1300        VK_SHIFT | VK_CONTROL | VK_MENU | VK_LWIN | VK_RWIN => {
1301            if state
1302                .last_reported_modifiers
1303                .is_some_and(|prev_modifiers| prev_modifiers == modifiers)
1304            {
1305                return None;
1306            }
1307            state.last_reported_modifiers = Some(modifiers);
1308            Some(PlatformInput::ModifiersChanged(ModifiersChangedEvent {
1309                modifiers,
1310                capslock: current_capslock(),
1311            }))
1312        }
1313        VK_PACKET => {
1314            translate_message(handle, wparam, lparam);
1315            None
1316        }
1317        VK_CAPITAL => {
1318            let capslock = current_capslock();
1319            if state
1320                .last_reported_capslock
1321                .is_some_and(|prev_capslock| prev_capslock == capslock)
1322            {
1323                return None;
1324            }
1325            state.last_reported_capslock = Some(capslock);
1326            Some(PlatformInput::ModifiersChanged(ModifiersChangedEvent {
1327                modifiers,
1328                capslock,
1329            }))
1330        }
1331        vkey => {
1332            let vkey = if vkey == VK_PROCESSKEY {
1333                VIRTUAL_KEY(unsafe { ImmGetVirtualKey(handle) } as u16)
1334            } else {
1335                vkey
1336            };
1337            let keystroke = parse_normal_key(vkey, lparam, modifiers)?;
1338            Some(f(keystroke))
1339        }
1340    }
1341}
1342
1343fn parse_immutable(vkey: VIRTUAL_KEY) -> Option<String> {
1344    Some(
1345        match vkey {
1346            VK_SPACE => "space",
1347            VK_BACK => "backspace",
1348            VK_RETURN => "enter",
1349            VK_TAB => "tab",
1350            VK_UP => "up",
1351            VK_DOWN => "down",
1352            VK_RIGHT => "right",
1353            VK_LEFT => "left",
1354            VK_HOME => "home",
1355            VK_END => "end",
1356            VK_PRIOR => "pageup",
1357            VK_NEXT => "pagedown",
1358            VK_BROWSER_BACK => "back",
1359            VK_BROWSER_FORWARD => "forward",
1360            VK_ESCAPE => "escape",
1361            VK_INSERT => "insert",
1362            VK_DELETE => "delete",
1363            VK_APPS => "menu",
1364            VK_F1 => "f1",
1365            VK_F2 => "f2",
1366            VK_F3 => "f3",
1367            VK_F4 => "f4",
1368            VK_F5 => "f5",
1369            VK_F6 => "f6",
1370            VK_F7 => "f7",
1371            VK_F8 => "f8",
1372            VK_F9 => "f9",
1373            VK_F10 => "f10",
1374            VK_F11 => "f11",
1375            VK_F12 => "f12",
1376            VK_F13 => "f13",
1377            VK_F14 => "f14",
1378            VK_F15 => "f15",
1379            VK_F16 => "f16",
1380            VK_F17 => "f17",
1381            VK_F18 => "f18",
1382            VK_F19 => "f19",
1383            VK_F20 => "f20",
1384            VK_F21 => "f21",
1385            VK_F22 => "f22",
1386            VK_F23 => "f23",
1387            VK_F24 => "f24",
1388            _ => return None,
1389        }
1390        .to_string(),
1391    )
1392}
1393
1394fn parse_normal_key(
1395    vkey: VIRTUAL_KEY,
1396    lparam: LPARAM,
1397    mut modifiers: Modifiers,
1398) -> Option<Keystroke> {
1399    let mut key_char = None;
1400    let key = parse_immutable(vkey).or_else(|| {
1401        let scan_code = lparam.hiword() & 0xFF;
1402        key_char = generate_key_char(
1403            vkey,
1404            scan_code as u32,
1405            modifiers.control,
1406            modifiers.shift,
1407            modifiers.alt,
1408        );
1409        get_keystroke_key(vkey, scan_code as u32, &mut modifiers)
1410    })?;
1411    Some(Keystroke {
1412        modifiers,
1413        key,
1414        key_char,
1415    })
1416}
1417
1418fn parse_ime_composition_string(ctx: HIMC, comp_type: IME_COMPOSITION_STRING) -> Option<String> {
1419    unsafe {
1420        let string_len = ImmGetCompositionStringW(ctx, comp_type, None, 0);
1421        if string_len >= 0 {
1422            let mut buffer = vec![0u8; string_len as usize + 2];
1423            ImmGetCompositionStringW(
1424                ctx,
1425                comp_type,
1426                Some(buffer.as_mut_ptr() as _),
1427                string_len as _,
1428            );
1429            let wstring = std::slice::from_raw_parts::<u16>(
1430                buffer.as_mut_ptr().cast::<u16>(),
1431                string_len as usize / 2,
1432            );
1433            Some(String::from_utf16_lossy(wstring))
1434        } else {
1435            None
1436        }
1437    }
1438}
1439
1440#[inline]
1441fn retrieve_composition_cursor_position(ctx: HIMC) -> usize {
1442    unsafe { ImmGetCompositionStringW(ctx, GCS_CURSORPOS, None, 0) as usize }
1443}
1444
1445#[inline]
1446fn is_virtual_key_pressed(vkey: VIRTUAL_KEY) -> bool {
1447    unsafe { GetKeyState(vkey.0 as i32) < 0 }
1448}
1449
1450#[inline]
1451pub(crate) fn current_modifiers() -> Modifiers {
1452    let altgr = is_virtual_key_pressed(VK_RMENU) && is_virtual_key_pressed(VK_LCONTROL);
1453
1454    Modifiers {
1455        control: is_virtual_key_pressed(VK_CONTROL) && !altgr,
1456        alt: is_virtual_key_pressed(VK_MENU) && !altgr,
1457        shift: is_virtual_key_pressed(VK_SHIFT),
1458        platform: is_virtual_key_pressed(VK_LWIN) || is_virtual_key_pressed(VK_RWIN),
1459        function: false,
1460    }
1461}
1462
1463#[inline]
1464pub(crate) fn current_capslock() -> Capslock {
1465    let on = unsafe { GetKeyState(VK_CAPITAL.0 as i32) & 1 } > 0;
1466    Capslock { on }
1467}
1468
1469fn get_client_area_insets(
1470    handle: HWND,
1471    is_maximized: bool,
1472    windows_version: WindowsVersion,
1473) -> RECT {
1474    // For maximized windows, Windows outdents the window rect from the screen's client rect
1475    // by `frame_thickness` on each edge, meaning `insets` must contain `frame_thickness`
1476    // on all sides (including the top) to avoid the client area extending onto adjacent
1477    // monitors.
1478    //
1479    // For non-maximized windows, things become complicated:
1480    //
1481    // - On Windows 10
1482    // The top inset must be zero, since if there is any nonclient area, Windows will draw
1483    // a full native titlebar outside the client area. (This doesn't occur in the maximized
1484    // case.)
1485    //
1486    // - On Windows 11
1487    // The top inset is calculated using an empirical formula that I derived through various
1488    // tests. Without this, the top 1-2 rows of pixels in our window would be obscured.
1489    let dpi = unsafe { GetDpiForWindow(handle) };
1490    let frame_thickness = get_frame_thickness(dpi);
1491    let top_insets = if is_maximized {
1492        frame_thickness
1493    } else {
1494        match windows_version {
1495            WindowsVersion::Win10 => 0,
1496            WindowsVersion::Win11 => (dpi as f32 / USER_DEFAULT_SCREEN_DPI as f32).round() as i32,
1497        }
1498    };
1499    RECT {
1500        left: frame_thickness,
1501        top: top_insets,
1502        right: frame_thickness,
1503        bottom: frame_thickness,
1504    }
1505}
1506
1507// there is some additional non-visible space when talking about window
1508// borders on Windows:
1509// - SM_CXSIZEFRAME: The resize handle.
1510// - SM_CXPADDEDBORDER: Additional border space that isn't part of the resize handle.
1511fn get_frame_thickness(dpi: u32) -> i32 {
1512    let resize_frame_thickness = unsafe { GetSystemMetricsForDpi(SM_CXSIZEFRAME, dpi) };
1513    let padding_thickness = unsafe { GetSystemMetricsForDpi(SM_CXPADDEDBORDER, dpi) };
1514    resize_frame_thickness + padding_thickness
1515}
1516
1517fn notify_frame_changed(handle: HWND) {
1518    unsafe {
1519        SetWindowPos(
1520            handle,
1521            None,
1522            0,
1523            0,
1524            0,
1525            0,
1526            SWP_FRAMECHANGED
1527                | SWP_NOACTIVATE
1528                | SWP_NOCOPYBITS
1529                | SWP_NOMOVE
1530                | SWP_NOOWNERZORDER
1531                | SWP_NOREPOSITION
1532                | SWP_NOSENDCHANGING
1533                | SWP_NOSIZE
1534                | SWP_NOZORDER,
1535        )
1536        .log_err();
1537    }
1538}