| 1 | #include "win32_window.h" |
| 2 | |
| 3 | #include <dwmapi.h> |
| 4 | #include <flutter_windows.h> |
| 5 | |
| 6 | #include "resource.h" |
| 7 | |
| 8 | namespace { |
| 9 | |
| 10 | /// Window attribute that enables dark mode window decorations. |
| 11 | /// |
| 12 | /// Redefined in case the developer's machine has a Windows SDK older than |
| 13 | /// version 10.0.22000.0. |
| 14 | /// See: https://docs.microsoft.com/windows/win32/api/dwmapi/ne-dwmapi-dwmwindowattribute |
| 15 | #ifndef DWMWA_USE_IMMERSIVE_DARK_MODE |
| 16 | #define DWMWA_USE_IMMERSIVE_DARK_MODE 20 |
| 17 | #endif |
| 18 | |
| 19 | constexpr const wchar_t kWindowClassName[] = L"FLUTTER_RUNNER_WIN32_WINDOW"; |
| 20 | |
| 21 | /// Registry key for app theme preference. |
| 22 | /// |
| 23 | /// A value of 0 indicates apps should use dark mode. A non-zero or missing |
| 24 | /// value indicates apps should use light mode. |
| 25 | constexpr const wchar_t kGetPreferredBrightnessRegKey[] = |
| 26 | L"Software\\Microsoft\\Windows\\CurrentVersion\\Themes\\Personalize"; |
| 27 | constexpr const wchar_t kGetPreferredBrightnessRegValue[] = L"AppsUseLightTheme"; |
| 28 | |
| 29 | // The number of Win32Window objects that currently exist. |
| 30 | static int g_active_window_count = 0; |
| 31 | |
| 32 | using EnableNonClientDpiScaling = BOOL __stdcall(HWND hwnd); |
| 33 | |
| 34 | // Scale helper to convert logical scaler values to physical using passed in |
| 35 | // scale factor |
| 36 | int Scale(int source, double scale_factor) { |
| 37 | return static_cast<int>(source * scale_factor); |
| 38 | } |
| 39 | |
| 40 | // Dynamically loads the |EnableNonClientDpiScaling| from the User32 module. |
| 41 | // This API is only needed for PerMonitor V1 awareness mode. |
| 42 | void EnableFullDpiSupportIfAvailable(HWND hwnd) { |
| 43 | HMODULE user32_module = LoadLibraryA("User32.dll"); |
| 44 | if (!user32_module) { |
| 45 | return; |
| 46 | } |
| 47 | auto enable_non_client_dpi_scaling = |
| 48 | reinterpret_cast<EnableNonClientDpiScaling*>( |
| 49 | GetProcAddress(user32_module, "EnableNonClientDpiScaling")); |
| 50 | if (enable_non_client_dpi_scaling != nullptr) { |
| 51 | enable_non_client_dpi_scaling(hwnd); |
| 52 | } |
| 53 | FreeLibrary(user32_module); |
| 54 | } |
| 55 | |
| 56 | } // namespace |
| 57 | |
| 58 | // Manages the Win32Window's window class registration. |
| 59 | class WindowClassRegistrar { |
| 60 | public: |
| 61 | ~WindowClassRegistrar() = default; |
| 62 | |
| 63 | // Returns the singleton registrar instance. |
| 64 | static WindowClassRegistrar* GetInstance() { |
| 65 | if (!instance_) { |
| 66 | instance_ = new WindowClassRegistrar(); |
| 67 | } |
| 68 | return instance_; |
| 69 | } |
| 70 | |
| 71 | // Returns the name of the window class, registering the class if it hasn't |
| 72 | // previously been registered. |
| 73 | const wchar_t* GetWindowClass(); |
| 74 | |
| 75 | // Unregisters the window class. Should only be called if there are no |
| 76 | // instances of the window. |
| 77 | void UnregisterWindowClass(); |
| 78 | |
| 79 | private: |
| 80 | WindowClassRegistrar() = default; |
| 81 | |
| 82 | static WindowClassRegistrar* instance_; |
| 83 | |
| 84 | bool class_registered_ = false; |
| 85 | }; |
| 86 | |
| 87 | WindowClassRegistrar* WindowClassRegistrar::instance_ = nullptr; |
| 88 | |
| 89 | const wchar_t* WindowClassRegistrar::GetWindowClass() { |
| 90 | if (!class_registered_) { |
| 91 | WNDCLASS window_class{}; |
| 92 | window_class.hCursor = LoadCursor(nullptr, IDC_ARROW); |
| 93 | window_class.lpszClassName = kWindowClassName; |
| 94 | window_class.style = CS_HREDRAW | CS_VREDRAW; |
| 95 | window_class.cbClsExtra = 0; |
| 96 | window_class.cbWndExtra = 0; |
| 97 | window_class.hInstance = GetModuleHandle(nullptr); |
| 98 | window_class.hIcon = |
| 99 | LoadIcon(window_class.hInstance, MAKEINTRESOURCE(IDI_APP_ICON)); |
| 100 | window_class.hbrBackground = 0; |
| 101 | window_class.lpszMenuName = nullptr; |
| 102 | window_class.lpfnWndProc = Win32Window::WndProc; |
| 103 | RegisterClass(&window_class); |
| 104 | class_registered_ = true; |
| 105 | } |
| 106 | return kWindowClassName; |
| 107 | } |
| 108 | |
| 109 | void WindowClassRegistrar::UnregisterWindowClass() { |
| 110 | UnregisterClass(kWindowClassName, nullptr); |
| 111 | class_registered_ = false; |
| 112 | } |
| 113 | |
| 114 | Win32Window::Win32Window() { |
| 115 | ++g_active_window_count; |
| 116 | } |
| 117 | |
| 118 | Win32Window::~Win32Window() { |
| 119 | --g_active_window_count; |
| 120 | Destroy(); |
| 121 | } |
| 122 | |
| 123 | bool Win32Window::Create(const std::wstring& title, |
| 124 | const Point& origin, |
| 125 | const Size& size) { |
| 126 | Destroy(); |
| 127 | |
| 128 | const wchar_t* window_class = |
| 129 | WindowClassRegistrar::GetInstance()->GetWindowClass(); |
| 130 | |
| 131 | const POINT target_point = {static_cast<LONG>(origin.x), |
| 132 | static_cast<LONG>(origin.y)}; |
| 133 | HMONITOR monitor = MonitorFromPoint(target_point, MONITOR_DEFAULTTONEAREST); |
| 134 | UINT dpi = FlutterDesktopGetDpiForMonitor(monitor); |
| 135 | double scale_factor = dpi / 96.0; |
| 136 | |
| 137 | HWND window = CreateWindow( |
| 138 | window_class, title.c_str(), WS_OVERLAPPEDWINDOW, |
| 139 | Scale(origin.x, scale_factor), Scale(origin.y, scale_factor), |
| 140 | Scale(size.width, scale_factor), Scale(size.height, scale_factor), |
| 141 | nullptr, nullptr, GetModuleHandle(nullptr), this); |
| 142 | |
| 143 | if (!window) { |
| 144 | return false; |
| 145 | } |
| 146 | |
| 147 | UpdateTheme(window); |
| 148 | |
| 149 | return OnCreate(); |
| 150 | } |
| 151 | |
| 152 | bool Win32Window::Show() { |
| 153 | return ShowWindow(window_handle_, SW_SHOWNORMAL); |
| 154 | } |
| 155 | |
| 156 | // static |
| 157 | LRESULT CALLBACK Win32Window::WndProc(HWND const window, |
| 158 | UINT const message, |
| 159 | WPARAM const wparam, |
| 160 | LPARAM const lparam) noexcept { |
| 161 | if (message == WM_NCCREATE) { |
| 162 | auto window_struct = reinterpret_cast<CREATESTRUCT*>(lparam); |
| 163 | SetWindowLongPtr(window, GWLP_USERDATA, |
| 164 | reinterpret_cast<LONG_PTR>(window_struct->lpCreateParams)); |
| 165 | |
| 166 | auto that = static_cast<Win32Window*>(window_struct->lpCreateParams); |
| 167 | EnableFullDpiSupportIfAvailable(window); |
| 168 | that->window_handle_ = window; |
| 169 | } else if (Win32Window* that = GetThisFromHandle(window)) { |
| 170 | return that->MessageHandler(window, message, wparam, lparam); |
| 171 | } |
| 172 | |
| 173 | return DefWindowProc(window, message, wparam, lparam); |
| 174 | } |
| 175 | |
| 176 | LRESULT |
| 177 | Win32Window::MessageHandler(HWND hwnd, |
| 178 | UINT const message, |
| 179 | WPARAM const wparam, |
| 180 | LPARAM const lparam) noexcept { |
| 181 | switch (message) { |
| 182 | case WM_DESTROY: |
| 183 | window_handle_ = nullptr; |
| 184 | Destroy(); |
| 185 | if (quit_on_close_) { |
| 186 | PostQuitMessage(0); |
| 187 | } |
| 188 | return 0; |
| 189 | |
| 190 | case WM_DPICHANGED: { |
| 191 | auto newRectSize = reinterpret_cast<RECT*>(lparam); |
| 192 | LONG newWidth = newRectSize->right - newRectSize->left; |
| 193 | LONG newHeight = newRectSize->bottom - newRectSize->top; |
| 194 | |
| 195 | SetWindowPos(hwnd, nullptr, newRectSize->left, newRectSize->top, newWidth, |
| 196 | newHeight, SWP_NOZORDER | SWP_NOACTIVATE); |
| 197 | |
| 198 | return 0; |
| 199 | } |
| 200 | case WM_SIZE: { |
| 201 | RECT rect = GetClientArea(); |
| 202 | if (child_content_ != nullptr) { |
| 203 | // Size and position the child window. |
| 204 | MoveWindow(child_content_, rect.left, rect.top, rect.right - rect.left, |
| 205 | rect.bottom - rect.top, TRUE); |
| 206 | } |
| 207 | return 0; |
| 208 | } |
| 209 | |
| 210 | case WM_ACTIVATE: |
| 211 | if (child_content_ != nullptr) { |
| 212 | SetFocus(child_content_); |
| 213 | } |
| 214 | return 0; |
| 215 | |
| 216 | case WM_DWMCOLORIZATIONCOLORCHANGED: |
| 217 | UpdateTheme(hwnd); |
| 218 | return 0; |
| 219 | } |
| 220 | |
| 221 | return DefWindowProc(window_handle_, message, wparam, lparam); |
| 222 | } |
| 223 | |
| 224 | void Win32Window::Destroy() { |
| 225 | OnDestroy(); |
| 226 | |
| 227 | if (window_handle_) { |
| 228 | DestroyWindow(window_handle_); |
| 229 | window_handle_ = nullptr; |
| 230 | } |
| 231 | if (g_active_window_count == 0) { |
| 232 | WindowClassRegistrar::GetInstance()->UnregisterWindowClass(); |
| 233 | } |
| 234 | } |
| 235 | |
| 236 | Win32Window* Win32Window::GetThisFromHandle(HWND const window) noexcept { |
| 237 | return reinterpret_cast<Win32Window*>( |
| 238 | GetWindowLongPtr(window, GWLP_USERDATA)); |
| 239 | } |
| 240 | |
| 241 | void Win32Window::SetChildContent(HWND content) { |
| 242 | child_content_ = content; |
| 243 | SetParent(content, window_handle_); |
| 244 | RECT frame = GetClientArea(); |
| 245 | |
| 246 | MoveWindow(content, frame.left, frame.top, frame.right - frame.left, |
| 247 | frame.bottom - frame.top, true); |
| 248 | |
| 249 | SetFocus(child_content_); |
| 250 | } |
| 251 | |
| 252 | RECT Win32Window::GetClientArea() { |
| 253 | RECT frame; |
| 254 | GetClientRect(window_handle_, &frame); |
| 255 | return frame; |
| 256 | } |
| 257 | |
| 258 | HWND Win32Window::GetHandle() { |
| 259 | return window_handle_; |
| 260 | } |
| 261 | |
| 262 | void Win32Window::SetQuitOnClose(bool quit_on_close) { |
| 263 | quit_on_close_ = quit_on_close; |
| 264 | } |
| 265 | |
| 266 | bool Win32Window::OnCreate() { |
| 267 | // No-op; provided for subclasses. |
| 268 | return true; |
| 269 | } |
| 270 | |
| 271 | void Win32Window::OnDestroy() { |
| 272 | // No-op; provided for subclasses. |
| 273 | } |
| 274 | |
| 275 | void Win32Window::UpdateTheme(HWND const window) { |
| 276 | DWORD light_mode; |
| 277 | DWORD light_mode_size = sizeof(light_mode); |
| 278 | LSTATUS result = RegGetValue(HKEY_CURRENT_USER, kGetPreferredBrightnessRegKey, |
| 279 | kGetPreferredBrightnessRegValue, |
| 280 | RRF_RT_REG_DWORD, nullptr, &light_mode, |
| 281 | &light_mode_size); |
| 282 | |
| 283 | if (result == ERROR_SUCCESS) { |
| 284 | BOOL enable_dark_mode = light_mode == 0; |
| 285 | DwmSetWindowAttribute(window, DWMWA_USE_IMMERSIVE_DARK_MODE, |
| 286 | &enable_dark_mode, sizeof(enable_dark_mode)); |
| 287 | } |
| 288 | } |