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;
  29pub(crate) const WM_GPUI_KEYDOWN: u32 = WM_USER + 8;
  30
  31const SIZE_MOVE_LOOP_TIMER_ID: usize = 1;
  32const AUTO_HIDE_TASKBAR_THICKNESS_PX: i32 = 1;
  33
  34impl WindowsWindowInner {
  35    pub(crate) fn handle_msg(
  36        self: &Rc<Self>,
  37        handle: HWND,
  38        msg: u32,
  39        wparam: WPARAM,
  40        lparam: LPARAM,
  41    ) -> LRESULT {
  42        let handled = match msg {
  43            WM_ACTIVATE => self.handle_activate_msg(wparam),
  44            WM_CREATE => self.handle_create_msg(handle),
  45            WM_MOVE => self.handle_move_msg(handle, lparam),
  46            WM_SIZE => self.handle_size_msg(wparam, lparam),
  47            WM_GETMINMAXINFO => self.handle_get_min_max_info_msg(lparam),
  48            WM_ENTERSIZEMOVE | WM_ENTERMENULOOP => self.handle_size_move_loop(handle),
  49            WM_EXITSIZEMOVE | WM_EXITMENULOOP => self.handle_size_move_loop_exit(handle),
  50            WM_TIMER => self.handle_timer_msg(handle, wparam),
  51            WM_NCCALCSIZE => self.handle_calc_client_size(handle, wparam, lparam),
  52            WM_DPICHANGED => self.handle_dpi_changed_msg(handle, wparam, lparam),
  53            WM_DISPLAYCHANGE => self.handle_display_change_msg(handle),
  54            WM_NCHITTEST => self.handle_hit_test_msg(handle, lparam),
  55            WM_PAINT => self.handle_paint_msg(handle),
  56            WM_CLOSE => self.handle_close_msg(),
  57            WM_DESTROY => self.handle_destroy_msg(handle),
  58            WM_MOUSEMOVE => self.handle_mouse_move_msg(handle, lparam, wparam),
  59            WM_MOUSELEAVE | WM_NCMOUSELEAVE => self.handle_mouse_leave_msg(),
  60            WM_NCMOUSEMOVE => self.handle_nc_mouse_move_msg(handle, lparam),
  61            // Treat double click as a second single click, since we track the double clicks ourselves.
  62            // If you don't interact with any elements, this will fall through to the windows default
  63            // behavior of toggling whether the window is maximized.
  64            WM_NCLBUTTONDBLCLK | WM_NCLBUTTONDOWN => {
  65                self.handle_nc_mouse_down_msg(handle, MouseButton::Left, wparam, lparam)
  66            }
  67            WM_NCRBUTTONDOWN => {
  68                self.handle_nc_mouse_down_msg(handle, MouseButton::Right, wparam, lparam)
  69            }
  70            WM_NCMBUTTONDOWN => {
  71                self.handle_nc_mouse_down_msg(handle, MouseButton::Middle, wparam, lparam)
  72            }
  73            WM_NCLBUTTONUP => {
  74                self.handle_nc_mouse_up_msg(handle, MouseButton::Left, wparam, lparam)
  75            }
  76            WM_NCRBUTTONUP => {
  77                self.handle_nc_mouse_up_msg(handle, MouseButton::Right, wparam, lparam)
  78            }
  79            WM_NCMBUTTONUP => {
  80                self.handle_nc_mouse_up_msg(handle, MouseButton::Middle, wparam, lparam)
  81            }
  82            WM_LBUTTONDOWN => self.handle_mouse_down_msg(handle, MouseButton::Left, lparam),
  83            WM_RBUTTONDOWN => self.handle_mouse_down_msg(handle, MouseButton::Right, lparam),
  84            WM_MBUTTONDOWN => self.handle_mouse_down_msg(handle, MouseButton::Middle, lparam),
  85            WM_XBUTTONDOWN => {
  86                self.handle_xbutton_msg(handle, wparam, lparam, Self::handle_mouse_down_msg)
  87            }
  88            WM_LBUTTONUP => self.handle_mouse_up_msg(handle, MouseButton::Left, lparam),
  89            WM_RBUTTONUP => self.handle_mouse_up_msg(handle, MouseButton::Right, lparam),
  90            WM_MBUTTONUP => self.handle_mouse_up_msg(handle, MouseButton::Middle, lparam),
  91            WM_XBUTTONUP => {
  92                self.handle_xbutton_msg(handle, wparam, lparam, Self::handle_mouse_up_msg)
  93            }
  94            WM_MOUSEWHEEL => self.handle_mouse_wheel_msg(handle, wparam, lparam),
  95            WM_MOUSEHWHEEL => self.handle_mouse_horizontal_wheel_msg(handle, wparam, lparam),
  96            WM_SYSKEYUP => self.handle_syskeyup_msg(wparam, lparam),
  97            WM_KEYUP => self.handle_keyup_msg(wparam, lparam),
  98            WM_GPUI_KEYDOWN => self.handle_keydown_msg(wparam, lparam),
  99            WM_CHAR => self.handle_char_msg(wparam),
 100            WM_IME_STARTCOMPOSITION => self.handle_ime_position(handle),
 101            WM_IME_COMPOSITION => self.handle_ime_composition(handle, lparam),
 102            WM_SETCURSOR => self.handle_set_cursor(handle, lparam),
 103            WM_SETTINGCHANGE => self.handle_system_settings_changed(handle, wparam, lparam),
 104            WM_INPUTLANGCHANGE => self.handle_input_language_changed(),
 105            WM_SHOWWINDOW => self.handle_window_visibility_changed(handle, wparam),
 106            WM_GPUI_CURSOR_STYLE_CHANGED => self.handle_cursor_changed(lparam),
 107            WM_GPUI_FORCE_UPDATE_WINDOW => self.draw_window(handle, true),
 108            WM_GPUI_GPU_DEVICE_LOST => self.handle_device_lost(lparam),
 109            _ => None,
 110        };
 111        if let Some(n) = handled {
 112            LRESULT(n)
 113        } else {
 114            unsafe { DefWindowProcW(handle, msg, wparam, lparam) }
 115        }
 116    }
 117
 118    fn handle_move_msg(&self, handle: HWND, lparam: LPARAM) -> Option<isize> {
 119        let origin = logical_point(
 120            lparam.signed_loword() as f32,
 121            lparam.signed_hiword() as f32,
 122            self.state.scale_factor.get(),
 123        );
 124        self.state.origin.set(origin);
 125        let size = self.state.logical_size.get();
 126        let center_x = origin.x.0 + size.width.0 / 2.;
 127        let center_y = origin.y.0 + size.height.0 / 2.;
 128        let monitor_bounds = self.state.display.get().bounds();
 129        if center_x < monitor_bounds.left().0
 130            || center_x > monitor_bounds.right().0
 131            || center_y < monitor_bounds.top().0
 132            || center_y > monitor_bounds.bottom().0
 133        {
 134            // center of the window may have moved to another monitor
 135            let monitor = unsafe { MonitorFromWindow(handle, MONITOR_DEFAULTTONULL) };
 136            // minimize the window can trigger this event too, in this case,
 137            // monitor is invalid, we do nothing.
 138            if !monitor.is_invalid() && self.state.display.get().handle != monitor {
 139                // we will get the same monitor if we only have one
 140                self.state
 141                    .display
 142                    .set(WindowsDisplay::new_with_handle(monitor).log_err()?);
 143            }
 144        }
 145        if let Some(mut callback) = self.state.callbacks.moved.take() {
 146            callback();
 147            self.state.callbacks.moved.set(Some(callback));
 148        }
 149        Some(0)
 150    }
 151
 152    fn handle_get_min_max_info_msg(&self, lparam: LPARAM) -> Option<isize> {
 153        let min_size = self.state.min_size?;
 154        let scale_factor = self.state.scale_factor.get();
 155        let boarder_offset = &self.state.border_offset;
 156
 157        unsafe {
 158            let minmax_info = &mut *(lparam.0 as *mut MINMAXINFO);
 159            minmax_info.ptMinTrackSize.x =
 160                min_size.width.scale(scale_factor).0 as i32 + boarder_offset.width_offset.get();
 161            minmax_info.ptMinTrackSize.y =
 162                min_size.height.scale(scale_factor).0 as i32 + boarder_offset.height_offset.get();
 163        }
 164        Some(0)
 165    }
 166
 167    fn handle_size_msg(&self, wparam: WPARAM, lparam: LPARAM) -> Option<isize> {
 168        // Don't resize the renderer when the window is minimized, but record that it was minimized so
 169        // that on restore the swap chain can be recreated via `update_drawable_size_even_if_unchanged`.
 170        if wparam.0 == SIZE_MINIMIZED as usize {
 171            self.state
 172                .restore_from_minimized
 173                .set(self.state.callbacks.request_frame.take());
 174            return Some(0);
 175        }
 176
 177        let width = lparam.loword().max(1) as i32;
 178        let height = lparam.hiword().max(1) as i32;
 179        let new_size = size(DevicePixels(width), DevicePixels(height));
 180
 181        let scale_factor = self.state.scale_factor.get();
 182        let mut should_resize_renderer = false;
 183        if let Some(restore_from_minimized) = self.state.restore_from_minimized.take() {
 184            self.state
 185                .callbacks
 186                .request_frame
 187                .set(Some(restore_from_minimized));
 188        } else {
 189            should_resize_renderer = true;
 190        }
 191
 192        self.handle_size_change(new_size, scale_factor, should_resize_renderer);
 193        Some(0)
 194    }
 195
 196    fn handle_size_change(
 197        &self,
 198        device_size: Size<DevicePixels>,
 199        scale_factor: f32,
 200        should_resize_renderer: bool,
 201    ) {
 202        let new_logical_size = device_size.to_pixels(scale_factor);
 203
 204        self.state.logical_size.set(new_logical_size);
 205        if should_resize_renderer
 206            && let Err(e) = self.state.renderer.borrow_mut().resize(device_size)
 207        {
 208            log::error!("Failed to resize renderer, invalidating devices: {}", e);
 209            self.state
 210                .invalidate_devices
 211                .store(true, std::sync::atomic::Ordering::Release);
 212        }
 213        if let Some(mut callback) = self.state.callbacks.resize.take() {
 214            callback(new_logical_size, scale_factor);
 215            self.state.callbacks.resize.set(Some(callback));
 216        }
 217    }
 218
 219    fn handle_size_move_loop(&self, handle: HWND) -> Option<isize> {
 220        unsafe {
 221            let ret = SetTimer(
 222                Some(handle),
 223                SIZE_MOVE_LOOP_TIMER_ID,
 224                USER_TIMER_MINIMUM,
 225                None,
 226            );
 227            if ret == 0 {
 228                log::error!(
 229                    "unable to create timer: {}",
 230                    std::io::Error::last_os_error()
 231                );
 232            }
 233        }
 234        None
 235    }
 236
 237    fn handle_size_move_loop_exit(&self, handle: HWND) -> Option<isize> {
 238        unsafe {
 239            KillTimer(Some(handle), SIZE_MOVE_LOOP_TIMER_ID).log_err();
 240        }
 241        None
 242    }
 243
 244    fn handle_timer_msg(&self, handle: HWND, wparam: WPARAM) -> Option<isize> {
 245        if wparam.0 == SIZE_MOVE_LOOP_TIMER_ID {
 246            for runnable in self.main_receiver.drain() {
 247                WindowsDispatcher::execute_runnable(runnable);
 248            }
 249            self.handle_paint_msg(handle)
 250        } else {
 251            None
 252        }
 253    }
 254
 255    fn handle_paint_msg(&self, handle: HWND) -> Option<isize> {
 256        self.draw_window(handle, false)
 257    }
 258
 259    fn handle_close_msg(&self) -> Option<isize> {
 260        let mut callback = self.state.callbacks.should_close.take()?;
 261        let should_close = callback();
 262        self.state.callbacks.should_close.set(Some(callback));
 263        if should_close { None } else { Some(0) }
 264    }
 265
 266    fn handle_destroy_msg(&self, handle: HWND) -> Option<isize> {
 267        let callback = { self.state.callbacks.close.take() };
 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 Some(mut func) = self.state.callbacks.input.take() else {
 287            return Some(1);
 288        };
 289        let scale_factor = self.state.scale_factor.get();
 290
 291        let pressed_button = match MODIFIERKEYS_FLAGS(wparam.loword() as u32) {
 292            flags if flags.contains(MK_LBUTTON) => Some(MouseButton::Left),
 293            flags if flags.contains(MK_RBUTTON) => Some(MouseButton::Right),
 294            flags if flags.contains(MK_MBUTTON) => Some(MouseButton::Middle),
 295            flags if flags.contains(MK_XBUTTON1) => {
 296                Some(MouseButton::Navigate(NavigationDirection::Back))
 297            }
 298            flags if flags.contains(MK_XBUTTON2) => {
 299                Some(MouseButton::Navigate(NavigationDirection::Forward))
 300            }
 301            _ => None,
 302        };
 303        let x = lparam.signed_loword() as f32;
 304        let y = lparam.signed_hiword() as f32;
 305        let input = PlatformInput::MouseMove(MouseMoveEvent {
 306            position: logical_point(x, y, scale_factor),
 307            pressed_button,
 308            modifiers: current_modifiers(),
 309        });
 310        let handled = !func(input).propagate;
 311        self.state.callbacks.input.set(Some(func));
 312
 313        if handled { Some(0) } else { Some(1) }
 314    }
 315
 316    fn handle_mouse_leave_msg(&self) -> Option<isize> {
 317        self.state.hovered.set(false);
 318        if let Some(mut callback) = self.state.callbacks.hovered_status_change.take() {
 319            callback(false);
 320            self.state
 321                .callbacks
 322                .hovered_status_change
 323                .set(Some(callback));
 324        }
 325
 326        Some(0)
 327    }
 328
 329    fn handle_syskeyup_msg(&self, wparam: WPARAM, lparam: LPARAM) -> Option<isize> {
 330        let input = handle_key_event(wparam, lparam, &self.state, |keystroke, _| {
 331            PlatformInput::KeyUp(KeyUpEvent { keystroke })
 332        })?;
 333        let mut func = self.state.callbacks.input.take()?;
 334
 335        func(input);
 336        self.state.callbacks.input.set(Some(func));
 337
 338        // Always return 0 to indicate that the message was handled, so we could properly handle `ModifiersChanged` event.
 339        Some(0)
 340    }
 341
 342    // It's a known bug that you can't trigger `ctrl-shift-0`. See:
 343    // https://superuser.com/questions/1455762/ctrl-shift-number-key-combination-has-stopped-working-for-a-few-numbers
 344    fn handle_keydown_msg(&self, wparam: WPARAM, lparam: LPARAM) -> Option<isize> {
 345        let Some(input) = handle_key_event(
 346            wparam,
 347            lparam,
 348            &self.state,
 349            |keystroke, prefer_character_input| {
 350                PlatformInput::KeyDown(KeyDownEvent {
 351                    keystroke,
 352                    is_held: lparam.0 & (0x1 << 30) > 0,
 353                    prefer_character_input,
 354                })
 355            },
 356        ) else {
 357            return Some(1);
 358        };
 359
 360        let Some(mut func) = self.state.callbacks.input.take() else {
 361            return Some(1);
 362        };
 363
 364        let handled = !func(input).propagate;
 365
 366        self.state.callbacks.input.set(Some(func));
 367
 368        if handled { Some(0) } else { Some(1) }
 369    }
 370
 371    fn handle_keyup_msg(&self, wparam: WPARAM, lparam: LPARAM) -> Option<isize> {
 372        let Some(input) = handle_key_event(wparam, lparam, &self.state, |keystroke, _| {
 373            PlatformInput::KeyUp(KeyUpEvent { keystroke })
 374        }) else {
 375            return Some(1);
 376        };
 377
 378        let Some(mut func) = self.state.callbacks.input.take() else {
 379            return Some(1);
 380        };
 381
 382        let handled = !func(input).propagate;
 383        self.state.callbacks.input.set(Some(func));
 384
 385        if handled { Some(0) } else { Some(1) }
 386    }
 387
 388    fn handle_char_msg(&self, wparam: WPARAM) -> Option<isize> {
 389        let input = self.parse_char_message(wparam)?;
 390        self.with_input_handler(|input_handler| {
 391            input_handler.replace_text_in_range(None, &input);
 392        });
 393
 394        Some(0)
 395    }
 396
 397    fn handle_mouse_down_msg(
 398        &self,
 399        handle: HWND,
 400        button: MouseButton,
 401        lparam: LPARAM,
 402    ) -> Option<isize> {
 403        unsafe { SetCapture(handle) };
 404
 405        let Some(mut func) = self.state.callbacks.input.take() else {
 406            return Some(1);
 407        };
 408        let x = lparam.signed_loword();
 409        let y = lparam.signed_hiword();
 410        let physical_point = point(DevicePixels(x as i32), DevicePixels(y as i32));
 411        let click_count = self.state.click_state.update(button, physical_point);
 412        let scale_factor = self.state.scale_factor.get();
 413
 414        let input = PlatformInput::MouseDown(MouseDownEvent {
 415            button,
 416            position: logical_point(x as f32, y as f32, scale_factor),
 417            modifiers: current_modifiers(),
 418            click_count,
 419            first_mouse: false,
 420        });
 421        let handled = !func(input).propagate;
 422        self.state.callbacks.input.set(Some(func));
 423
 424        if handled { Some(0) } else { Some(1) }
 425    }
 426
 427    fn handle_mouse_up_msg(
 428        &self,
 429        _handle: HWND,
 430        button: MouseButton,
 431        lparam: LPARAM,
 432    ) -> Option<isize> {
 433        unsafe { ReleaseCapture().log_err() };
 434
 435        let Some(mut func) = self.state.callbacks.input.take() else {
 436            return Some(1);
 437        };
 438        let x = lparam.signed_loword() as f32;
 439        let y = lparam.signed_hiword() as f32;
 440        let click_count = self.state.click_state.current_count.get();
 441        let scale_factor = self.state.scale_factor.get();
 442
 443        let input = PlatformInput::MouseUp(MouseUpEvent {
 444            button,
 445            position: logical_point(x, y, scale_factor),
 446            modifiers: current_modifiers(),
 447            click_count,
 448        });
 449        let handled = !func(input).propagate;
 450        self.state.callbacks.input.set(Some(func));
 451
 452        if handled { Some(0) } else { Some(1) }
 453    }
 454
 455    fn handle_xbutton_msg(
 456        &self,
 457        handle: HWND,
 458        wparam: WPARAM,
 459        lparam: LPARAM,
 460        handler: impl Fn(&Self, HWND, MouseButton, LPARAM) -> Option<isize>,
 461    ) -> Option<isize> {
 462        let nav_dir = match wparam.hiword() {
 463            XBUTTON1 => NavigationDirection::Back,
 464            XBUTTON2 => NavigationDirection::Forward,
 465            _ => return Some(1),
 466        };
 467        handler(self, handle, MouseButton::Navigate(nav_dir), lparam)
 468    }
 469
 470    fn handle_mouse_wheel_msg(
 471        &self,
 472        handle: HWND,
 473        wparam: WPARAM,
 474        lparam: LPARAM,
 475    ) -> Option<isize> {
 476        let modifiers = current_modifiers();
 477
 478        let Some(mut func) = self.state.callbacks.input.take() else {
 479            return Some(1);
 480        };
 481        let scale_factor = self.state.scale_factor.get();
 482        let wheel_scroll_amount = match modifiers.shift {
 483            true => self
 484                .system_settings()
 485                .mouse_wheel_settings
 486                .wheel_scroll_chars
 487                .get(),
 488            false => self
 489                .system_settings()
 490                .mouse_wheel_settings
 491                .wheel_scroll_lines
 492                .get(),
 493        };
 494
 495        let wheel_distance =
 496            (wparam.signed_hiword() as f32 / WHEEL_DELTA as f32) * wheel_scroll_amount as f32;
 497        let mut cursor_point = POINT {
 498            x: lparam.signed_loword().into(),
 499            y: lparam.signed_hiword().into(),
 500        };
 501        unsafe { ScreenToClient(handle, &mut cursor_point).ok().log_err() };
 502        let input = PlatformInput::ScrollWheel(ScrollWheelEvent {
 503            position: logical_point(cursor_point.x as f32, cursor_point.y as f32, scale_factor),
 504            delta: ScrollDelta::Lines(match modifiers.shift {
 505                true => Point {
 506                    x: wheel_distance,
 507                    y: 0.0,
 508                },
 509                false => Point {
 510                    y: wheel_distance,
 511                    x: 0.0,
 512                },
 513            }),
 514            modifiers,
 515            touch_phase: TouchPhase::Moved,
 516        });
 517        let handled = !func(input).propagate;
 518        self.state.callbacks.input.set(Some(func));
 519
 520        if handled { Some(0) } else { Some(1) }
 521    }
 522
 523    fn handle_mouse_horizontal_wheel_msg(
 524        &self,
 525        handle: HWND,
 526        wparam: WPARAM,
 527        lparam: LPARAM,
 528    ) -> Option<isize> {
 529        let Some(mut func) = self.state.callbacks.input.take() else {
 530            return Some(1);
 531        };
 532        let scale_factor = self.state.scale_factor.get();
 533        let wheel_scroll_chars = self
 534            .system_settings()
 535            .mouse_wheel_settings
 536            .wheel_scroll_chars
 537            .get();
 538
 539        let wheel_distance =
 540            (-wparam.signed_hiword() as f32 / WHEEL_DELTA as f32) * wheel_scroll_chars as f32;
 541        let mut cursor_point = POINT {
 542            x: lparam.signed_loword().into(),
 543            y: lparam.signed_hiword().into(),
 544        };
 545        unsafe { ScreenToClient(handle, &mut cursor_point).ok().log_err() };
 546        let event = PlatformInput::ScrollWheel(ScrollWheelEvent {
 547            position: logical_point(cursor_point.x as f32, cursor_point.y as f32, scale_factor),
 548            delta: ScrollDelta::Lines(Point {
 549                x: wheel_distance,
 550                y: 0.0,
 551            }),
 552            modifiers: current_modifiers(),
 553            touch_phase: TouchPhase::Moved,
 554        });
 555        let handled = !func(event).propagate;
 556        self.state.callbacks.input.set(Some(func));
 557
 558        if handled { Some(0) } else { Some(1) }
 559    }
 560
 561    fn retrieve_caret_position(&self) -> Option<POINT> {
 562        self.with_input_handler_and_scale_factor(|input_handler, scale_factor| {
 563            let caret_range = input_handler.selected_text_range(false)?;
 564            let caret_position = input_handler.bounds_for_range(caret_range.range)?;
 565            Some(POINT {
 566                // logical to physical
 567                x: (caret_position.origin.x.0 * scale_factor) as i32,
 568                y: (caret_position.origin.y.0 * scale_factor) as i32
 569                    + ((caret_position.size.height.0 * scale_factor) as i32 / 2),
 570            })
 571        })
 572    }
 573
 574    fn handle_ime_position(&self, handle: HWND) -> Option<isize> {
 575        unsafe {
 576            let ctx = ImmGetContext(handle);
 577
 578            let Some(caret_position) = self.retrieve_caret_position() else {
 579                return Some(0);
 580            };
 581            {
 582                let config = COMPOSITIONFORM {
 583                    dwStyle: CFS_POINT,
 584                    ptCurrentPos: caret_position,
 585                    ..Default::default()
 586                };
 587                ImmSetCompositionWindow(ctx, &config as _).ok().log_err();
 588            }
 589            {
 590                let config = CANDIDATEFORM {
 591                    dwStyle: CFS_CANDIDATEPOS,
 592                    ptCurrentPos: caret_position,
 593                    ..Default::default()
 594                };
 595                ImmSetCandidateWindow(ctx, &config as _).ok().log_err();
 596            }
 597            ImmReleaseContext(handle, ctx).ok().log_err();
 598            Some(0)
 599        }
 600    }
 601
 602    fn handle_ime_composition(&self, handle: HWND, lparam: LPARAM) -> Option<isize> {
 603        let ctx = unsafe { ImmGetContext(handle) };
 604        let result = self.handle_ime_composition_inner(ctx, lparam);
 605        unsafe { ImmReleaseContext(handle, ctx).ok().log_err() };
 606        result
 607    }
 608
 609    fn handle_ime_composition_inner(&self, ctx: HIMC, lparam: LPARAM) -> Option<isize> {
 610        let lparam = lparam.0 as u32;
 611        if lparam == 0 {
 612            // Japanese IME may send this message with lparam = 0, which indicates that
 613            // there is no composition string.
 614            self.with_input_handler(|input_handler| {
 615                input_handler.replace_text_in_range(None, "");
 616            })?;
 617            Some(0)
 618        } else {
 619            if lparam & GCS_COMPSTR.0 > 0 {
 620                let comp_string = parse_ime_composition_string(ctx, GCS_COMPSTR)?;
 621                let caret_pos =
 622                    (!comp_string.is_empty() && lparam & GCS_CURSORPOS.0 > 0).then(|| {
 623                        let pos = retrieve_composition_cursor_position(ctx);
 624                        pos..pos
 625                    });
 626                self.with_input_handler(|input_handler| {
 627                    input_handler.replace_and_mark_text_in_range(None, &comp_string, caret_pos);
 628                })?;
 629            }
 630            if lparam & GCS_RESULTSTR.0 > 0 {
 631                let comp_result = parse_ime_composition_string(ctx, GCS_RESULTSTR)?;
 632                self.with_input_handler(|input_handler| {
 633                    input_handler.replace_text_in_range(None, &comp_result);
 634                })?;
 635                return Some(0);
 636            }
 637
 638            // currently, we don't care other stuff
 639            None
 640        }
 641    }
 642
 643    /// SEE: https://learn.microsoft.com/en-us/windows/win32/winmsg/wm-nccalcsize
 644    fn handle_calc_client_size(
 645        &self,
 646        handle: HWND,
 647        wparam: WPARAM,
 648        lparam: LPARAM,
 649    ) -> Option<isize> {
 650        if !self.hide_title_bar || self.state.is_fullscreen() || wparam.0 == 0 {
 651            return None;
 652        }
 653
 654        let is_maximized = self.state.is_maximized();
 655        let insets = get_client_area_insets(handle, is_maximized, self.windows_version);
 656        // wparam is TRUE so lparam points to an NCCALCSIZE_PARAMS structure
 657        let mut params = lparam.0 as *mut NCCALCSIZE_PARAMS;
 658        let mut requested_client_rect = unsafe { &mut ((*params).rgrc) };
 659
 660        requested_client_rect[0].left += insets.left;
 661        requested_client_rect[0].top += insets.top;
 662        requested_client_rect[0].right -= insets.right;
 663        requested_client_rect[0].bottom -= insets.bottom;
 664
 665        // Fix auto hide taskbar not showing. This solution is based on the approach
 666        // used by Chrome. However, it may result in one row of pixels being obscured
 667        // in our client area. But as Chrome says, "there seems to be no better solution."
 668        if is_maximized
 669            && let Some(taskbar_position) = self.system_settings().auto_hide_taskbar_position.get()
 670        {
 671            // For the auto-hide taskbar, adjust in by 1 pixel on taskbar edge,
 672            // so the window isn't treated as a "fullscreen app", which would cause
 673            // the taskbar to disappear.
 674            match taskbar_position {
 675                AutoHideTaskbarPosition::Left => {
 676                    requested_client_rect[0].left += AUTO_HIDE_TASKBAR_THICKNESS_PX
 677                }
 678                AutoHideTaskbarPosition::Top => {
 679                    requested_client_rect[0].top += AUTO_HIDE_TASKBAR_THICKNESS_PX
 680                }
 681                AutoHideTaskbarPosition::Right => {
 682                    requested_client_rect[0].right -= AUTO_HIDE_TASKBAR_THICKNESS_PX
 683                }
 684                AutoHideTaskbarPosition::Bottom => {
 685                    requested_client_rect[0].bottom -= AUTO_HIDE_TASKBAR_THICKNESS_PX
 686                }
 687            }
 688        }
 689
 690        Some(0)
 691    }
 692
 693    fn handle_activate_msg(self: &Rc<Self>, wparam: WPARAM) -> Option<isize> {
 694        let activated = wparam.loword() > 0;
 695        let this = self.clone();
 696        self.executor
 697            .spawn(async move {
 698                if let Some(mut func) = this.state.callbacks.active_status_change.take() {
 699                    func(activated);
 700                    this.state.callbacks.active_status_change.set(Some(func));
 701                }
 702            })
 703            .detach();
 704
 705        None
 706    }
 707
 708    fn handle_create_msg(&self, handle: HWND) -> Option<isize> {
 709        if self.hide_title_bar {
 710            notify_frame_changed(handle);
 711            Some(0)
 712        } else {
 713            None
 714        }
 715    }
 716
 717    fn handle_dpi_changed_msg(
 718        &self,
 719        handle: HWND,
 720        wparam: WPARAM,
 721        lparam: LPARAM,
 722    ) -> Option<isize> {
 723        let new_dpi = wparam.loword() as f32;
 724
 725        let is_maximized = self.state.is_maximized();
 726        let new_scale_factor = new_dpi / USER_DEFAULT_SCREEN_DPI as f32;
 727        self.state.scale_factor.set(new_scale_factor);
 728        self.state.border_offset.update(handle).log_err();
 729
 730        if is_maximized {
 731            // Get the monitor and its work area at the new DPI
 732            let monitor = unsafe { MonitorFromWindow(handle, MONITOR_DEFAULTTONEAREST) };
 733            let mut monitor_info: MONITORINFO = unsafe { std::mem::zeroed() };
 734            monitor_info.cbSize = std::mem::size_of::<MONITORINFO>() as u32;
 735            if unsafe { GetMonitorInfoW(monitor, &mut monitor_info) }.as_bool() {
 736                let work_area = monitor_info.rcWork;
 737                let width = work_area.right - work_area.left;
 738                let height = work_area.bottom - work_area.top;
 739
 740                // Update the window size to match the new monitor work area
 741                // This will trigger WM_SIZE which will handle the size change
 742                unsafe {
 743                    SetWindowPos(
 744                        handle,
 745                        None,
 746                        work_area.left,
 747                        work_area.top,
 748                        width,
 749                        height,
 750                        SWP_NOZORDER | SWP_NOACTIVATE | SWP_FRAMECHANGED,
 751                    )
 752                    .context("unable to set maximized window position after dpi has changed")
 753                    .log_err();
 754                }
 755
 756                // SetWindowPos may not send WM_SIZE for maximized windows in some cases,
 757                // so we manually update the size to ensure proper rendering
 758                let device_size = size(DevicePixels(width), DevicePixels(height));
 759                self.handle_size_change(device_size, new_scale_factor, true);
 760            }
 761        } else {
 762            // For non-maximized windows, use the suggested RECT from the system
 763            let rect = unsafe { &*(lparam.0 as *const RECT) };
 764            let width = rect.right - rect.left;
 765            let height = rect.bottom - rect.top;
 766            // this will emit `WM_SIZE` and `WM_MOVE` right here
 767            // even before this function returns
 768            // the new size is handled in `WM_SIZE`
 769            unsafe {
 770                SetWindowPos(
 771                    handle,
 772                    None,
 773                    rect.left,
 774                    rect.top,
 775                    width,
 776                    height,
 777                    SWP_NOZORDER | SWP_NOACTIVATE,
 778                )
 779                .context("unable to set window position after dpi has changed")
 780                .log_err();
 781            }
 782        }
 783
 784        Some(0)
 785    }
 786
 787    /// The following conditions will trigger this event:
 788    /// 1. The monitor on which the window is located goes offline or changes resolution.
 789    /// 2. Another monitor goes offline, is plugged in, or changes resolution.
 790    ///
 791    /// In either case, the window will only receive information from the monitor on which
 792    /// it is located.
 793    ///
 794    /// For example, in the case of condition 2, where the monitor on which the window is
 795    /// located has actually changed nothing, it will still receive this event.
 796    fn handle_display_change_msg(&self, handle: HWND) -> Option<isize> {
 797        // NOTE:
 798        // Even the `lParam` holds the resolution of the screen, we just ignore it.
 799        // Because WM_DPICHANGED, WM_MOVE, WM_SIZE will come first, window reposition and resize
 800        // are handled there.
 801        // So we only care about if monitor is disconnected.
 802        let previous_monitor = self.state.display.get();
 803        if WindowsDisplay::is_connected(previous_monitor.handle) {
 804            // we are fine, other display changed
 805            return None;
 806        }
 807        // display disconnected
 808        // in this case, the OS will move our window to another monitor, and minimize it.
 809        // we deminimize the window and query the monitor after moving
 810        unsafe {
 811            let _ = ShowWindow(handle, SW_SHOWNORMAL);
 812        };
 813        let new_monitor = unsafe { MonitorFromWindow(handle, MONITOR_DEFAULTTONULL) };
 814        // all monitors disconnected
 815        if new_monitor.is_invalid() {
 816            log::error!("No monitor detected!");
 817            return None;
 818        }
 819        let new_display = WindowsDisplay::new_with_handle(new_monitor).log_err()?;
 820        self.state.display.set(new_display);
 821        Some(0)
 822    }
 823
 824    fn handle_hit_test_msg(&self, handle: HWND, lparam: LPARAM) -> Option<isize> {
 825        if !self.is_movable || self.state.is_fullscreen() {
 826            return None;
 827        }
 828
 829        let callback = self.state.callbacks.hit_test_window_control.take();
 830        let drag_area = if let Some(mut callback) = callback {
 831            let area = callback();
 832            self.state
 833                .callbacks
 834                .hit_test_window_control
 835                .set(Some(callback));
 836            if let Some(area) = area {
 837                match area {
 838                    WindowControlArea::Drag => Some(HTCAPTION as _),
 839                    WindowControlArea::Close => return Some(HTCLOSE as _),
 840                    WindowControlArea::Max => return Some(HTMAXBUTTON as _),
 841                    WindowControlArea::Min => return Some(HTMINBUTTON as _),
 842                }
 843            } else {
 844                None
 845            }
 846        } else {
 847            None
 848        };
 849
 850        if !self.hide_title_bar {
 851            // If the OS draws the title bar, we don't need to handle hit test messages.
 852            return drag_area;
 853        }
 854
 855        let dpi = unsafe { GetDpiForWindow(handle) };
 856        // We do not use the OS title bar, so the default `DefWindowProcW` will only register a 1px edge for resizes
 857        // We need to calculate the frame thickness ourselves and do the hit test manually.
 858        let frame_y = get_frame_thicknessx(dpi);
 859        let frame_x = get_frame_thicknessy(dpi);
 860        let mut cursor_point = POINT {
 861            x: lparam.signed_loword().into(),
 862            y: lparam.signed_hiword().into(),
 863        };
 864
 865        unsafe { ScreenToClient(handle, &mut cursor_point).ok().log_err() };
 866        if !self.state.is_maximized() && 0 <= cursor_point.y && cursor_point.y <= frame_y {
 867            // x-axis actually goes from -frame_x to 0
 868            return Some(if cursor_point.x <= 0 {
 869                HTTOPLEFT
 870            } else {
 871                let mut rect = Default::default();
 872                unsafe { GetWindowRect(handle, &mut rect) }.log_err();
 873                // right and bottom bounds of RECT are exclusive, thus `-1`
 874                let right = rect.right - rect.left - 1;
 875                // the bounds include the padding frames, so accomodate for both of them
 876                if right - 2 * frame_x <= cursor_point.x {
 877                    HTTOPRIGHT
 878                } else {
 879                    HTTOP
 880                }
 881            } as _);
 882        }
 883
 884        drag_area
 885    }
 886
 887    fn handle_nc_mouse_move_msg(&self, handle: HWND, lparam: LPARAM) -> Option<isize> {
 888        self.start_tracking_mouse(handle, TME_LEAVE | TME_NONCLIENT);
 889
 890        let mut func = self.state.callbacks.input.take()?;
 891        let scale_factor = self.state.scale_factor.get();
 892
 893        let mut cursor_point = POINT {
 894            x: lparam.signed_loword().into(),
 895            y: lparam.signed_hiword().into(),
 896        };
 897        unsafe { ScreenToClient(handle, &mut cursor_point).ok().log_err() };
 898        let input = PlatformInput::MouseMove(MouseMoveEvent {
 899            position: logical_point(cursor_point.x as f32, cursor_point.y as f32, scale_factor),
 900            pressed_button: None,
 901            modifiers: current_modifiers(),
 902        });
 903        let handled = !func(input).propagate;
 904        self.state.callbacks.input.set(Some(func));
 905
 906        if handled { Some(0) } else { None }
 907    }
 908
 909    fn handle_nc_mouse_down_msg(
 910        &self,
 911        handle: HWND,
 912        button: MouseButton,
 913        wparam: WPARAM,
 914        lparam: LPARAM,
 915    ) -> Option<isize> {
 916        if let Some(mut func) = self.state.callbacks.input.take() {
 917            let scale_factor = self.state.scale_factor.get();
 918            let mut cursor_point = POINT {
 919                x: lparam.signed_loword().into(),
 920                y: lparam.signed_hiword().into(),
 921            };
 922            unsafe { ScreenToClient(handle, &mut cursor_point).ok().log_err() };
 923            let physical_point = point(DevicePixels(cursor_point.x), DevicePixels(cursor_point.y));
 924            let click_count = self.state.click_state.update(button, physical_point);
 925
 926            let input = PlatformInput::MouseDown(MouseDownEvent {
 927                button,
 928                position: logical_point(cursor_point.x as f32, cursor_point.y as f32, scale_factor),
 929                modifiers: current_modifiers(),
 930                click_count,
 931                first_mouse: false,
 932            });
 933            let result = func(input);
 934            let handled = !result.propagate || result.default_prevented;
 935            self.state.callbacks.input.set(Some(func));
 936
 937            if handled {
 938                return Some(0);
 939            }
 940        } else {
 941        };
 942
 943        // Since these are handled in handle_nc_mouse_up_msg we must prevent the default window proc
 944        if button == MouseButton::Left {
 945            match wparam.0 as u32 {
 946                HTMINBUTTON => self.state.nc_button_pressed.set(Some(HTMINBUTTON)),
 947                HTMAXBUTTON => self.state.nc_button_pressed.set(Some(HTMAXBUTTON)),
 948                HTCLOSE => self.state.nc_button_pressed.set(Some(HTCLOSE)),
 949                _ => return None,
 950            };
 951            Some(0)
 952        } else {
 953            None
 954        }
 955    }
 956
 957    fn handle_nc_mouse_up_msg(
 958        &self,
 959        handle: HWND,
 960        button: MouseButton,
 961        wparam: WPARAM,
 962        lparam: LPARAM,
 963    ) -> Option<isize> {
 964        if let Some(mut func) = self.state.callbacks.input.take() {
 965            let scale_factor = self.state.scale_factor.get();
 966
 967            let mut cursor_point = POINT {
 968                x: lparam.signed_loword().into(),
 969                y: lparam.signed_hiword().into(),
 970            };
 971            unsafe { ScreenToClient(handle, &mut cursor_point).ok().log_err() };
 972            let input = PlatformInput::MouseUp(MouseUpEvent {
 973                button,
 974                position: logical_point(cursor_point.x as f32, cursor_point.y as f32, scale_factor),
 975                modifiers: current_modifiers(),
 976                click_count: 1,
 977            });
 978            let handled = !func(input).propagate;
 979            self.state.callbacks.input.set(Some(func));
 980
 981            if handled {
 982                return Some(0);
 983            }
 984        } else {
 985        }
 986
 987        let last_pressed = self.state.nc_button_pressed.take();
 988        if button == MouseButton::Left
 989            && let Some(last_pressed) = last_pressed
 990        {
 991            let handled = match (wparam.0 as u32, last_pressed) {
 992                (HTMINBUTTON, HTMINBUTTON) => {
 993                    unsafe { ShowWindowAsync(handle, SW_MINIMIZE).ok().log_err() };
 994                    true
 995                }
 996                (HTMAXBUTTON, HTMAXBUTTON) => {
 997                    if self.state.is_maximized() {
 998                        unsafe { ShowWindowAsync(handle, SW_NORMAL).ok().log_err() };
 999                    } else {
1000                        unsafe { ShowWindowAsync(handle, SW_MAXIMIZE).ok().log_err() };
1001                    }
1002                    true
1003                }
1004                (HTCLOSE, HTCLOSE) => {
1005                    unsafe {
1006                        PostMessageW(Some(handle), WM_CLOSE, WPARAM::default(), LPARAM::default())
1007                            .log_err()
1008                    };
1009                    true
1010                }
1011                _ => false,
1012            };
1013            if handled {
1014                return Some(0);
1015            }
1016        }
1017
1018        None
1019    }
1020
1021    fn handle_cursor_changed(&self, lparam: LPARAM) -> Option<isize> {
1022        let had_cursor = self.state.current_cursor.get().is_some();
1023
1024        self.state.current_cursor.set(if lparam.0 == 0 {
1025            None
1026        } else {
1027            Some(HCURSOR(lparam.0 as _))
1028        });
1029
1030        if had_cursor != self.state.current_cursor.get().is_some() {
1031            unsafe { SetCursor(self.state.current_cursor.get()) };
1032        }
1033
1034        Some(0)
1035    }
1036
1037    fn handle_set_cursor(&self, handle: HWND, lparam: LPARAM) -> Option<isize> {
1038        if unsafe { !IsWindowEnabled(handle).as_bool() }
1039            || matches!(
1040                lparam.loword() as u32,
1041                HTLEFT
1042                    | HTRIGHT
1043                    | HTTOP
1044                    | HTTOPLEFT
1045                    | HTTOPRIGHT
1046                    | HTBOTTOM
1047                    | HTBOTTOMLEFT
1048                    | HTBOTTOMRIGHT
1049            )
1050        {
1051            return None;
1052        }
1053        unsafe {
1054            SetCursor(self.state.current_cursor.get());
1055        };
1056        Some(0)
1057    }
1058
1059    fn handle_system_settings_changed(
1060        &self,
1061        handle: HWND,
1062        wparam: WPARAM,
1063        lparam: LPARAM,
1064    ) -> Option<isize> {
1065        if wparam.0 != 0 {
1066            let display = self.state.display.get();
1067            self.state.click_state.system_update(wparam.0);
1068            self.state.border_offset.update(handle).log_err();
1069            // system settings may emit a window message which wants to take the refcell self.state, so drop it
1070
1071            self.system_settings().update(display, wparam.0);
1072        } else {
1073            self.handle_system_theme_changed(handle, lparam)?;
1074        };
1075        // Force to trigger WM_NCCALCSIZE event to ensure that we handle auto hide
1076        // taskbar correctly.
1077        notify_frame_changed(handle);
1078
1079        Some(0)
1080    }
1081
1082    fn handle_system_theme_changed(&self, handle: HWND, lparam: LPARAM) -> Option<isize> {
1083        // lParam is a pointer to a string that indicates the area containing the system parameter
1084        // that was changed.
1085        let parameter = PCWSTR::from_raw(lparam.0 as _);
1086        if unsafe { !parameter.is_null() && !parameter.is_empty() }
1087            && let Some(parameter_string) = unsafe { parameter.to_string() }.log_err()
1088        {
1089            log::info!("System settings changed: {}", parameter_string);
1090            if parameter_string.as_str() == "ImmersiveColorSet" {
1091                let new_appearance = system_appearance()
1092                    .context("unable to get system appearance when handling ImmersiveColorSet")
1093                    .log_err()?;
1094
1095                if new_appearance != self.state.appearance.get() {
1096                    self.state.appearance.set(new_appearance);
1097                    let mut callback = self.state.callbacks.appearance_changed.take()?;
1098
1099                    callback();
1100                    self.state.callbacks.appearance_changed.set(Some(callback));
1101                    configure_dwm_dark_mode(handle, new_appearance);
1102                }
1103            }
1104        }
1105        Some(0)
1106    }
1107
1108    fn handle_input_language_changed(&self) -> Option<isize> {
1109        unsafe {
1110            PostMessageW(
1111                Some(self.platform_window_handle),
1112                WM_GPUI_KEYBOARD_LAYOUT_CHANGED,
1113                WPARAM(self.validation_number),
1114                LPARAM(0),
1115            )
1116            .log_err();
1117        }
1118        Some(0)
1119    }
1120
1121    fn handle_window_visibility_changed(&self, handle: HWND, wparam: WPARAM) -> Option<isize> {
1122        if wparam.0 == 1 {
1123            self.draw_window(handle, false);
1124        }
1125        None
1126    }
1127
1128    fn handle_device_lost(&self, lparam: LPARAM) -> Option<isize> {
1129        let devices = lparam.0 as *const DirectXDevices;
1130        let devices = unsafe { &*devices };
1131        if let Err(err) = self
1132            .state
1133            .renderer
1134            .borrow_mut()
1135            .handle_device_lost(&devices)
1136        {
1137            panic!("Device lost: {err}");
1138        }
1139        Some(0)
1140    }
1141
1142    #[inline]
1143    fn draw_window(&self, handle: HWND, force_render: bool) -> Option<isize> {
1144        let mut request_frame = self.state.callbacks.request_frame.take()?;
1145
1146        // we are instructing gpui to force render a frame, this will
1147        // re-populate all the gpu textures for us so we can resume drawing in
1148        // case we disabled drawing earlier due to a device loss
1149        self.state.renderer.borrow_mut().mark_drawable();
1150        request_frame(RequestFrameOptions {
1151            require_presentation: false,
1152            force_render,
1153        });
1154
1155        self.state.callbacks.request_frame.set(Some(request_frame));
1156        unsafe { ValidateRect(Some(handle), None).ok().log_err() };
1157
1158        Some(0)
1159    }
1160
1161    #[inline]
1162    fn parse_char_message(&self, wparam: WPARAM) -> Option<String> {
1163        let code_point = wparam.loword();
1164
1165        // https://www.unicode.org/versions/Unicode16.0.0/core-spec/chapter-3/#G2630
1166        match code_point {
1167            0xD800..=0xDBFF => {
1168                // High surrogate, wait for low surrogate
1169                self.state.pending_surrogate.set(Some(code_point));
1170                None
1171            }
1172            0xDC00..=0xDFFF => {
1173                if let Some(high_surrogate) = self.state.pending_surrogate.take() {
1174                    // Low surrogate, combine with pending high surrogate
1175                    String::from_utf16(&[high_surrogate, code_point]).ok()
1176                } else {
1177                    // Invalid low surrogate without a preceding high surrogate
1178                    log::warn!(
1179                        "Received low surrogate without a preceding high surrogate: {code_point:x}"
1180                    );
1181                    None
1182                }
1183            }
1184            _ => {
1185                self.state.pending_surrogate.set(None);
1186                char::from_u32(code_point as u32)
1187                    .filter(|c| !c.is_control())
1188                    .map(|c| c.to_string())
1189            }
1190        }
1191    }
1192
1193    fn start_tracking_mouse(&self, handle: HWND, flags: TRACKMOUSEEVENT_FLAGS) {
1194        if !self.state.hovered.get() {
1195            self.state.hovered.set(true);
1196            unsafe {
1197                TrackMouseEvent(&mut TRACKMOUSEEVENT {
1198                    cbSize: std::mem::size_of::<TRACKMOUSEEVENT>() as u32,
1199                    dwFlags: flags,
1200                    hwndTrack: handle,
1201                    dwHoverTime: HOVER_DEFAULT,
1202                })
1203                .log_err()
1204            };
1205            if let Some(mut callback) = self.state.callbacks.hovered_status_change.take() {
1206                callback(true);
1207                self.state
1208                    .callbacks
1209                    .hovered_status_change
1210                    .set(Some(callback));
1211            }
1212        }
1213    }
1214
1215    fn with_input_handler<F, R>(&self, f: F) -> Option<R>
1216    where
1217        F: FnOnce(&mut PlatformInputHandler) -> R,
1218    {
1219        let mut input_handler = self.state.input_handler.take()?;
1220        let result = f(&mut input_handler);
1221        self.state.input_handler.set(Some(input_handler));
1222        Some(result)
1223    }
1224
1225    fn with_input_handler_and_scale_factor<F, R>(&self, f: F) -> Option<R>
1226    where
1227        F: FnOnce(&mut PlatformInputHandler, f32) -> Option<R>,
1228    {
1229        let mut input_handler = self.state.input_handler.take()?;
1230        let scale_factor = self.state.scale_factor.get();
1231
1232        let result = f(&mut input_handler, scale_factor);
1233        self.state.input_handler.set(Some(input_handler));
1234        result
1235    }
1236}
1237
1238fn handle_key_event<F>(
1239    wparam: WPARAM,
1240    lparam: LPARAM,
1241    state: &WindowsWindowState,
1242    f: F,
1243) -> Option<PlatformInput>
1244where
1245    F: FnOnce(Keystroke, bool) -> PlatformInput,
1246{
1247    let virtual_key = VIRTUAL_KEY(wparam.loword());
1248    let modifiers = current_modifiers();
1249
1250    match virtual_key {
1251        VK_SHIFT | VK_CONTROL | VK_MENU | VK_LMENU | VK_RMENU | VK_LWIN | VK_RWIN => {
1252            if state
1253                .last_reported_modifiers
1254                .get()
1255                .is_some_and(|prev_modifiers| prev_modifiers == modifiers)
1256            {
1257                return None;
1258            }
1259            state.last_reported_modifiers.set(Some(modifiers));
1260            Some(PlatformInput::ModifiersChanged(ModifiersChangedEvent {
1261                modifiers,
1262                capslock: current_capslock(),
1263            }))
1264        }
1265        VK_PACKET => None,
1266        VK_CAPITAL => {
1267            let capslock = current_capslock();
1268            if state
1269                .last_reported_capslock
1270                .get()
1271                .is_some_and(|prev_capslock| prev_capslock == capslock)
1272            {
1273                return None;
1274            }
1275            state.last_reported_capslock.set(Some(capslock));
1276            Some(PlatformInput::ModifiersChanged(ModifiersChangedEvent {
1277                modifiers,
1278                capslock,
1279            }))
1280        }
1281        vkey => {
1282            let keystroke = parse_normal_key(vkey, lparam, modifiers)?;
1283            Some(f(keystroke.0, keystroke.1))
1284        }
1285    }
1286}
1287
1288fn parse_immutable(vkey: VIRTUAL_KEY) -> Option<String> {
1289    Some(
1290        match vkey {
1291            VK_SPACE => "space",
1292            VK_BACK => "backspace",
1293            VK_RETURN => "enter",
1294            VK_TAB => "tab",
1295            VK_UP => "up",
1296            VK_DOWN => "down",
1297            VK_RIGHT => "right",
1298            VK_LEFT => "left",
1299            VK_HOME => "home",
1300            VK_END => "end",
1301            VK_PRIOR => "pageup",
1302            VK_NEXT => "pagedown",
1303            VK_BROWSER_BACK => "back",
1304            VK_BROWSER_FORWARD => "forward",
1305            VK_ESCAPE => "escape",
1306            VK_INSERT => "insert",
1307            VK_DELETE => "delete",
1308            VK_APPS => "menu",
1309            VK_F1 => "f1",
1310            VK_F2 => "f2",
1311            VK_F3 => "f3",
1312            VK_F4 => "f4",
1313            VK_F5 => "f5",
1314            VK_F6 => "f6",
1315            VK_F7 => "f7",
1316            VK_F8 => "f8",
1317            VK_F9 => "f9",
1318            VK_F10 => "f10",
1319            VK_F11 => "f11",
1320            VK_F12 => "f12",
1321            VK_F13 => "f13",
1322            VK_F14 => "f14",
1323            VK_F15 => "f15",
1324            VK_F16 => "f16",
1325            VK_F17 => "f17",
1326            VK_F18 => "f18",
1327            VK_F19 => "f19",
1328            VK_F20 => "f20",
1329            VK_F21 => "f21",
1330            VK_F22 => "f22",
1331            VK_F23 => "f23",
1332            VK_F24 => "f24",
1333            _ => return None,
1334        }
1335        .to_string(),
1336    )
1337}
1338
1339fn parse_normal_key(
1340    vkey: VIRTUAL_KEY,
1341    lparam: LPARAM,
1342    mut modifiers: Modifiers,
1343) -> Option<(Keystroke, bool)> {
1344    let (key_char, prefer_character_input) = process_key(vkey, lparam.hiword());
1345
1346    let key = parse_immutable(vkey).or_else(|| {
1347        let scan_code = lparam.hiword() & 0xFF;
1348        get_keystroke_key(vkey, scan_code as u32, &mut modifiers)
1349    })?;
1350
1351    Some((
1352        Keystroke {
1353            modifiers,
1354            key,
1355            key_char,
1356        },
1357        prefer_character_input,
1358    ))
1359}
1360
1361fn process_key(vkey: VIRTUAL_KEY, scan_code: u16) -> (Option<String>, bool) {
1362    let mut keyboard_state = [0u8; 256];
1363    unsafe {
1364        if GetKeyboardState(&mut keyboard_state).is_err() {
1365            return (None, false);
1366        }
1367    }
1368
1369    let mut buffer_c = [0u16; 8];
1370    let result_c = unsafe {
1371        ToUnicode(
1372            vkey.0 as u32,
1373            scan_code as u32,
1374            Some(&keyboard_state),
1375            &mut buffer_c,
1376            0x4,
1377        )
1378    };
1379
1380    if result_c == 0 {
1381        return (None, false);
1382    }
1383
1384    let c = &buffer_c[..result_c.unsigned_abs() as usize];
1385    let key_char = String::from_utf16(c)
1386        .ok()
1387        .filter(|s| !s.is_empty() && !s.chars().next().unwrap().is_control());
1388
1389    if result_c < 0 {
1390        return (key_char, true);
1391    }
1392
1393    if key_char.is_none() {
1394        return (None, false);
1395    }
1396
1397    // Workaround for some bug that makes the compiler think keyboard_state is still zeroed out
1398    let keyboard_state = std::hint::black_box(keyboard_state);
1399    let ctrl_down = (keyboard_state[VK_CONTROL.0 as usize] & 0x80) != 0;
1400    let alt_down = (keyboard_state[VK_MENU.0 as usize] & 0x80) != 0;
1401    let win_down = (keyboard_state[VK_LWIN.0 as usize] & 0x80) != 0
1402        || (keyboard_state[VK_RWIN.0 as usize] & 0x80) != 0;
1403
1404    let has_modifiers = ctrl_down || alt_down || win_down;
1405    if !has_modifiers {
1406        return (key_char, false);
1407    }
1408
1409    let mut state_no_modifiers = keyboard_state;
1410    state_no_modifiers[VK_CONTROL.0 as usize] = 0;
1411    state_no_modifiers[VK_LCONTROL.0 as usize] = 0;
1412    state_no_modifiers[VK_RCONTROL.0 as usize] = 0;
1413    state_no_modifiers[VK_MENU.0 as usize] = 0;
1414    state_no_modifiers[VK_LMENU.0 as usize] = 0;
1415    state_no_modifiers[VK_RMENU.0 as usize] = 0;
1416    state_no_modifiers[VK_LWIN.0 as usize] = 0;
1417    state_no_modifiers[VK_RWIN.0 as usize] = 0;
1418
1419    let mut buffer_c_no_modifiers = [0u16; 8];
1420    let result_c_no_modifiers = unsafe {
1421        ToUnicode(
1422            vkey.0 as u32,
1423            scan_code as u32,
1424            Some(&state_no_modifiers),
1425            &mut buffer_c_no_modifiers,
1426            0x4,
1427        )
1428    };
1429
1430    let c_no_modifiers = &buffer_c_no_modifiers[..result_c_no_modifiers.unsigned_abs() as usize];
1431    (
1432        key_char,
1433        result_c != result_c_no_modifiers || c != c_no_modifiers,
1434    )
1435}
1436
1437fn parse_ime_composition_string(ctx: HIMC, comp_type: IME_COMPOSITION_STRING) -> Option<String> {
1438    unsafe {
1439        let string_len = ImmGetCompositionStringW(ctx, comp_type, None, 0);
1440        if string_len >= 0 {
1441            let mut buffer = vec![0u8; string_len as usize + 2];
1442            ImmGetCompositionStringW(
1443                ctx,
1444                comp_type,
1445                Some(buffer.as_mut_ptr() as _),
1446                string_len as _,
1447            );
1448            let wstring = std::slice::from_raw_parts::<u16>(
1449                buffer.as_mut_ptr().cast::<u16>(),
1450                string_len as usize / 2,
1451            );
1452            Some(String::from_utf16_lossy(wstring))
1453        } else {
1454            None
1455        }
1456    }
1457}
1458
1459#[inline]
1460fn retrieve_composition_cursor_position(ctx: HIMC) -> usize {
1461    unsafe { ImmGetCompositionStringW(ctx, GCS_CURSORPOS, None, 0) as usize }
1462}
1463
1464#[inline]
1465fn is_virtual_key_pressed(vkey: VIRTUAL_KEY) -> bool {
1466    unsafe { GetKeyState(vkey.0 as i32) < 0 }
1467}
1468
1469#[inline]
1470pub(crate) fn current_modifiers() -> Modifiers {
1471    Modifiers {
1472        control: is_virtual_key_pressed(VK_CONTROL),
1473        alt: is_virtual_key_pressed(VK_MENU),
1474        shift: is_virtual_key_pressed(VK_SHIFT),
1475        platform: is_virtual_key_pressed(VK_LWIN) || is_virtual_key_pressed(VK_RWIN),
1476        function: false,
1477    }
1478}
1479
1480#[inline]
1481pub(crate) fn current_capslock() -> Capslock {
1482    let on = unsafe { GetKeyState(VK_CAPITAL.0 as i32) & 1 } > 0;
1483    Capslock { on }
1484}
1485
1486fn get_client_area_insets(
1487    handle: HWND,
1488    is_maximized: bool,
1489    windows_version: WindowsVersion,
1490) -> RECT {
1491    // For maximized windows, Windows outdents the window rect from the screen's client rect
1492    // by `frame_thickness` on each edge, meaning `insets` must contain `frame_thickness`
1493    // on all sides (including the top) to avoid the client area extending onto adjacent
1494    // monitors.
1495    //
1496    // For non-maximized windows, things become complicated:
1497    //
1498    // - On Windows 10
1499    // The top inset must be zero, since if there is any nonclient area, Windows will draw
1500    // a full native titlebar outside the client area. (This doesn't occur in the maximized
1501    // case.)
1502    //
1503    // - On Windows 11
1504    // The top inset is calculated using an empirical formula that I derived through various
1505    // tests. Without this, the top 1-2 rows of pixels in our window would be obscured.
1506    let dpi = unsafe { GetDpiForWindow(handle) };
1507    let frame_thickness = get_frame_thicknessx(dpi);
1508    let top_insets = if is_maximized {
1509        frame_thickness
1510    } else {
1511        match windows_version {
1512            WindowsVersion::Win10 => 0,
1513            WindowsVersion::Win11 => (dpi as f32 / USER_DEFAULT_SCREEN_DPI as f32).round() as i32,
1514        }
1515    };
1516    RECT {
1517        left: frame_thickness,
1518        top: top_insets,
1519        right: frame_thickness,
1520        bottom: frame_thickness,
1521    }
1522}
1523
1524// there is some additional non-visible space when talking about window
1525// borders on Windows:
1526// - SM_CXSIZEFRAME: The resize handle.
1527// - SM_CXPADDEDBORDER: Additional border space that isn't part of the resize handle.
1528fn get_frame_thicknessx(dpi: u32) -> i32 {
1529    let resize_frame_thickness = unsafe { GetSystemMetricsForDpi(SM_CXSIZEFRAME, dpi) };
1530    let padding_thickness = unsafe { GetSystemMetricsForDpi(SM_CXPADDEDBORDER, dpi) };
1531    resize_frame_thickness + padding_thickness
1532}
1533
1534fn get_frame_thicknessy(dpi: u32) -> i32 {
1535    let resize_frame_thickness = unsafe { GetSystemMetricsForDpi(SM_CYSIZEFRAME, dpi) };
1536    let padding_thickness = unsafe { GetSystemMetricsForDpi(SM_CXPADDEDBORDER, dpi) };
1537    resize_frame_thickness + padding_thickness
1538}
1539
1540fn notify_frame_changed(handle: HWND) {
1541    unsafe {
1542        SetWindowPos(
1543            handle,
1544            None,
1545            0,
1546            0,
1547            0,
1548            0,
1549            SWP_FRAMECHANGED
1550                | SWP_NOACTIVATE
1551                | SWP_NOCOPYBITS
1552                | SWP_NOMOVE
1553                | SWP_NOOWNERZORDER
1554                | SWP_NOREPOSITION
1555                | SWP_NOSENDCHANGING
1556                | SWP_NOSIZE
1557                | SWP_NOZORDER,
1558        )
1559        .log_err();
1560    }
1561}