fix windows cpu hight

analysis_options.yaml

@@ -0,0 +1,28 @@
+# This file configures the analyzer, which statically analyzes Dart code to
+# check for errors, warnings, and lints.
+#
+# The issues identified by the analyzer are surfaced in the UI of Dart-enabled
+# IDEs (https://dart.dev/tools#ides-and-editors). The analyzer can also be
+# invoked from the command line by running `flutter analyze`.
+
+# The following line activates a set of recommended lints for Flutter apps,
+# packages, and plugins designed to encourage good coding practices.
+include: package:flutter_lints/flutter.yaml
+
+linter:
+  # The lint rules applied to this project can be customized in the
+  # section below to disable rules from the `package:flutter_lints/flutter.yaml`
+  # included above or to enable additional rules. A list of all available lints
+  # and their documentation is published at https://dart.dev/lints.
+  #
+  # Instead of disabling a lint rule for the entire project in the
+  # section below, it can also be suppressed for a single line of code
+  # or a specific dart file by using the `// ignore: name_of_lint` and
+  # `// ignore_for_file: name_of_lint` syntax on the line or in the file
+  # producing the lint.
+  rules:
+    # avoid_print: false  # Uncomment to disable the `avoid_print` rule
+    # prefer_single_quotes: true  # Uncomment to enable the `prefer_single_quotes` rule
+
+# Additional information about this file can be found at
+# https://dart.dev/guides/language/analysis-options

windows/CMakeLists.txt

@@ -1,13 +1,16 @@
-cmake_minimum_required(VERSION 3.15)
+# Project-level configuration.
+cmake_minimum_required(VERSION 3.14)
 project(flutter_clock LANGUAGES CXX)
 
+# The name of the executable created for the application. Change this to change
+# the on-disk name of your application.
 set(BINARY_NAME "flutter_clock")
 
-cmake_policy(SET CMP0063 NEW)
+# Explicitly opt in to modern CMake behaviors to avoid warnings with recent
+# versions of CMake.
+cmake_policy(VERSION 3.14...3.25)
 
-set(CMAKE_INSTALL_RPATH "$ORIGIN/lib")
-
-# Configure build options.
+# Define build configuration option.
 get_property(IS_MULTICONFIG GLOBAL PROPERTY GENERATOR_IS_MULTI_CONFIG)
 if(IS_MULTICONFIG)
   set(CMAKE_CONFIGURATION_TYPES "Debug;Profile;Release"
@@ -20,7 +23,7 @@ else()
       "Debug" "Profile" "Release")
   endif()
 endif()
-
+# Define settings for the Profile build mode.
 set(CMAKE_EXE_LINKER_FLAGS_PROFILE "${CMAKE_EXE_LINKER_FLAGS_RELEASE}")
 set(CMAKE_SHARED_LINKER_FLAGS_PROFILE "${CMAKE_SHARED_LINKER_FLAGS_RELEASE}")
 set(CMAKE_C_FLAGS_PROFILE "${CMAKE_C_FLAGS_RELEASE}")
@@ -30,6 +33,10 @@ set(CMAKE_CXX_FLAGS_PROFILE "${CMAKE_CXX_FLAGS_RELEASE}")
 add_definitions(-DUNICODE -D_UNICODE)
 
 # Compilation settings that should be applied to most targets.
+#
+# Be cautious about adding new options here, as plugins use this function by
+# default. In most cases, you should add new options to specific targets instead
+# of modifying this function.
 function(APPLY_STANDARD_SETTINGS TARGET)
   target_compile_features(${TARGET} PUBLIC cxx_std_17)
   target_compile_options(${TARGET} PRIVATE /W4 /WX /wd"4100")
@@ -38,14 +45,14 @@ function(APPLY_STANDARD_SETTINGS TARGET)
   target_compile_definitions(${TARGET} PRIVATE "$<$<CONFIG:Debug>:_DEBUG>")
 endfunction()
 
-set(FLUTTER_MANAGED_DIR "${CMAKE_CURRENT_SOURCE_DIR}/flutter")
-
 # Flutter library and tool build rules.
+set(FLUTTER_MANAGED_DIR "${CMAKE_CURRENT_SOURCE_DIR}/flutter")
 add_subdirectory(${FLUTTER_MANAGED_DIR})
 
-# Application build
+# Application build; see runner/CMakeLists.txt.
 add_subdirectory("runner")
 
+
 # Generated plugin build rules, which manage building the plugins and adding
 # them to the application.
 include(flutter/generated_plugins.cmake)
@@ -80,6 +87,12 @@ if(PLUGIN_BUNDLED_LIBRARIES)
     COMPONENT Runtime)
 endif()
 
+# Copy the native assets provided by the build.dart from all packages.
+set(NATIVE_ASSETS_DIR "${PROJECT_BUILD_DIR}native_assets/windows/")
+install(DIRECTORY "${NATIVE_ASSETS_DIR}"
+   DESTINATION "${INSTALL_BUNDLE_LIB_DIR}"
+   COMPONENT Runtime)
+
 # Fully re-copy the assets directory on each build to avoid having stale files
 # from a previous install.
 set(FLUTTER_ASSET_DIR_NAME "flutter_assets")

windows/flutter/CMakeLists.txt

@@ -1,4 +1,5 @@
-cmake_minimum_required(VERSION 3.15)
+# This file controls Flutter-level build steps. It should not be edited.
+cmake_minimum_required(VERSION 3.14)
 
 set(EPHEMERAL_DIR "${CMAKE_CURRENT_SOURCE_DIR}/ephemeral")
 
@@ -9,6 +10,11 @@ include(${EPHEMERAL_DIR}/generated_config.cmake)
 # https://github.com/flutter/flutter/issues/57146.
 set(WRAPPER_ROOT "${EPHEMERAL_DIR}/cpp_client_wrapper")
 
+# Set fallback configurations for older versions of the flutter tool.
+if (NOT DEFINED FLUTTER_TARGET_PLATFORM)
+  set(FLUTTER_TARGET_PLATFORM "windows-x64")
+endif()
+
 # === Flutter Library ===
 set(FLUTTER_LIBRARY "${EPHEMERAL_DIR}/flutter_windows.dll")
 
@@ -91,7 +97,7 @@ add_custom_command(
   COMMAND ${CMAKE_COMMAND} -E env
     ${FLUTTER_TOOL_ENVIRONMENT}
     "${FLUTTER_ROOT}/packages/flutter_tools/bin/tool_backend.bat"
-      windows-x64 $<CONFIG>
+      ${FLUTTER_TARGET_PLATFORM} $<CONFIG>
   VERBATIM
 )
 add_custom_target(flutter_assemble DEPENDS

windows/runner/CMakeLists.txt

@@ -1,18 +1,40 @@
-cmake_minimum_required(VERSION 3.15)
+cmake_minimum_required(VERSION 3.14)
 project(runner LANGUAGES CXX)
 
+# Define the application target. To change its name, change BINARY_NAME in the
+# top-level CMakeLists.txt, not the value here, or `flutter run` will no longer
+# work.
+#
+# Any new source files that you add to the application should be added here.
 add_executable(${BINARY_NAME} WIN32
   "flutter_window.cpp"
   "main.cpp"
-  "run_loop.cpp"
   "utils.cpp"
   "win32_window.cpp"
   "${FLUTTER_MANAGED_DIR}/generated_plugin_registrant.cc"
   "Runner.rc"
   "runner.exe.manifest"
 )
+
+# Apply the standard set of build settings. This can be removed for applications
+# that need different build settings.
 apply_standard_settings(${BINARY_NAME})
+
+# Add preprocessor definitions for the build version.
+target_compile_definitions(${BINARY_NAME} PRIVATE "FLUTTER_VERSION=\"${FLUTTER_VERSION}\"")
+target_compile_definitions(${BINARY_NAME} PRIVATE "FLUTTER_VERSION_MAJOR=${FLUTTER_VERSION_MAJOR}")
+target_compile_definitions(${BINARY_NAME} PRIVATE "FLUTTER_VERSION_MINOR=${FLUTTER_VERSION_MINOR}")
+target_compile_definitions(${BINARY_NAME} PRIVATE "FLUTTER_VERSION_PATCH=${FLUTTER_VERSION_PATCH}")
+target_compile_definitions(${BINARY_NAME} PRIVATE "FLUTTER_VERSION_BUILD=${FLUTTER_VERSION_BUILD}")
+
+# Disable Windows macros that collide with C++ standard library functions.
 target_compile_definitions(${BINARY_NAME} PRIVATE "NOMINMAX")
+
+# Add dependency libraries and include directories. Add any application-specific
+# dependencies here.
 target_link_libraries(${BINARY_NAME} PRIVATE flutter flutter_wrapper_app)
+target_link_libraries(${BINARY_NAME} PRIVATE "dwmapi.lib")
 target_include_directories(${BINARY_NAME} PRIVATE "${CMAKE_SOURCE_DIR}")
+
+# Run the Flutter tool portions of the build. This must not be removed.
 add_dependencies(${BINARY_NAME} flutter_assemble)

windows/runner/Runner.rc

@@ -60,14 +60,14 @@ IDI_APP_ICON            ICON                    "resources\\app_icon.ico"
 // Version
 //
 
-#ifdef FLUTTER_BUILD_NUMBER
-#define VERSION_AS_NUMBER FLUTTER_BUILD_NUMBER
+#if defined(FLUTTER_VERSION_MAJOR) && defined(FLUTTER_VERSION_MINOR) && defined(FLUTTER_VERSION_PATCH) && defined(FLUTTER_VERSION_BUILD)
+#define VERSION_AS_NUMBER FLUTTER_VERSION_MAJOR,FLUTTER_VERSION_MINOR,FLUTTER_VERSION_PATCH,FLUTTER_VERSION_BUILD
 #else
-#define VERSION_AS_NUMBER 1,0,0
+#define VERSION_AS_NUMBER 1,0,0,0
 #endif
 
-#ifdef FLUTTER_BUILD_NAME
-#define VERSION_AS_STRING #FLUTTER_BUILD_NAME
+#if defined(FLUTTER_VERSION)
+#define VERSION_AS_STRING FLUTTER_VERSION
 #else
 #define VERSION_AS_STRING "1.0.0"
 #endif
@@ -90,10 +90,10 @@ BEGIN
         BLOCK "040904e4"
         BEGIN
             VALUE "CompanyName", "me.yoqi.flutter" "\0"
-            VALUE "FileDescription", "A new Flutter application." "\0"
+            VALUE "FileDescription", "flutter_clock" "\0"
             VALUE "FileVersion", VERSION_AS_STRING "\0"
             VALUE "InternalName", "flutter_clock" "\0"
-            VALUE "LegalCopyright", "Copyright (C) 2021 me.yoqi.flutter. All rights reserved." "\0"
+            VALUE "LegalCopyright", "Copyright (C) 2025 me.yoqi.flutter. All rights reserved." "\0"
             VALUE "OriginalFilename", "flutter_clock.exe" "\0"
             VALUE "ProductName", "flutter_clock" "\0"
             VALUE "ProductVersion", VERSION_AS_STRING "\0"

windows/runner/flutter_window.cpp

@@ -4,9 +4,8 @@
 
 #include "flutter/generated_plugin_registrant.h"
 
-FlutterWindow::FlutterWindow(RunLoop* run_loop,
-                             const flutter::DartProject& project)
-    : run_loop_(run_loop), project_(project) {}
+FlutterWindow::FlutterWindow(const flutter::DartProject& project)
+    : project_(project) {}
 
 FlutterWindow::~FlutterWindow() {}
 
@@ -26,14 +25,22 @@ bool FlutterWindow::OnCreate() {
     return false;
   }
   RegisterPlugins(flutter_controller_->engine());
-  run_loop_->RegisterFlutterInstance(flutter_controller_->engine());
   SetChildContent(flutter_controller_->view()->GetNativeWindow());
+
+  flutter_controller_->engine()->SetNextFrameCallback([&]() {
+    this->Show();
+  });
+
+  // Flutter can complete the first frame before the "show window" callback is
+  // registered. The following call ensures a frame is pending to ensure the
+  // window is shown. It is a no-op if the first frame hasn't completed yet.
+  flutter_controller_->ForceRedraw();
+
   return true;
 }
 
 void FlutterWindow::OnDestroy() {
   if (flutter_controller_) {
-    run_loop_->UnregisterFlutterInstance(flutter_controller_->engine());
     flutter_controller_ = nullptr;
   }
 
@@ -44,7 +51,7 @@ LRESULT
 FlutterWindow::MessageHandler(HWND hwnd, UINT const message,
                               WPARAM const wparam,
                               LPARAM const lparam) noexcept {
-  // Give Flutter, including plugins, an opporutunity to handle window messages.
+  // Give Flutter, including plugins, an opportunity to handle window messages.
   if (flutter_controller_) {
     std::optional<LRESULT> result =
         flutter_controller_->HandleTopLevelWindowProc(hwnd, message, wparam,

windows/runner/flutter_window.h

@@ -6,16 +6,13 @@
 
 #include <memory>
 
-#include "run_loop.h"
 #include "win32_window.h"
 
 // A window that does nothing but host a Flutter view.
 class FlutterWindow : public Win32Window {
  public:
-  // Creates a new FlutterWindow driven by the |run_loop|, hosting a
-  // Flutter view running |project|.
-  explicit FlutterWindow(RunLoop* run_loop,
-                         const flutter::DartProject& project);
+  // Creates a new FlutterWindow hosting a Flutter view running |project|.
+  explicit FlutterWindow(const flutter::DartProject& project);
   virtual ~FlutterWindow();
 
  protected:
@@ -26,9 +23,6 @@ class FlutterWindow : public Win32Window {
                          LPARAM const lparam) noexcept override;
 
  private:
-  // The run loop driving events for this window.
-  RunLoop* run_loop_;
-
   // The project to run.
   flutter::DartProject project_;
 

windows/runner/main.cpp

@@ -3,7 +3,6 @@
 #include <windows.h>
 
 #include "flutter_window.h"
-#include "run_loop.h"
 #include "utils.h"
 
 int APIENTRY wWinMain(_In_ HINSTANCE instance, _In_opt_ HINSTANCE prev,
@@ -18,8 +17,6 @@ int APIENTRY wWinMain(_In_ HINSTANCE instance, _In_opt_ HINSTANCE prev,
   // plugins.
   ::CoInitializeEx(nullptr, COINIT_APARTMENTTHREADED);
 
-  RunLoop run_loop;
-
   flutter::DartProject project(L"data");
 
   std::vector<std::string> command_line_arguments =
@@ -27,15 +24,19 @@ int APIENTRY wWinMain(_In_ HINSTANCE instance, _In_opt_ HINSTANCE prev,
 
   project.set_dart_entrypoint_arguments(std::move(command_line_arguments));
 
-  FlutterWindow window(&run_loop, project);
+  FlutterWindow window(project);
   Win32Window::Point origin(10, 10);
   Win32Window::Size size(1280, 720);
-  if (!window.CreateAndShow(L"flutter_clock", origin, size)) {
+  if (!window.Create(L"flutter_clock", origin, size)) {
     return EXIT_FAILURE;
   }
   window.SetQuitOnClose(true);
 
-  run_loop.Run();
+  ::MSG msg;
+  while (::GetMessage(&msg, nullptr, 0, 0)) {
+    ::TranslateMessage(&msg);
+    ::DispatchMessage(&msg);
+  }
 
   ::CoUninitialize();
   return EXIT_SUCCESS;

windows/runner/run_loop.cpp

@@ -1,66 +0,0 @@
-#include "run_loop.h"
-
-#include <windows.h>
-
-#include <algorithm>
-
-RunLoop::RunLoop() {}
-
-RunLoop::~RunLoop() {}
-
-void RunLoop::Run() {
-  bool keep_running = true;
-  TimePoint next_flutter_event_time = TimePoint::clock::now();
-  while (keep_running) {
-    std::chrono::nanoseconds wait_duration =
-        std::max(std::chrono::nanoseconds(0),
-                 next_flutter_event_time - TimePoint::clock::now());
-    ::MsgWaitForMultipleObjects(
-        0, nullptr, FALSE, static_cast<DWORD>(wait_duration.count() / 1000),
-        QS_ALLINPUT);
-    bool processed_events = false;
-    MSG message;
-    // All pending Windows messages must be processed; MsgWaitForMultipleObjects
-    // won't return again for items left in the queue after PeekMessage.
-    while (::PeekMessage(&message, nullptr, 0, 0, PM_REMOVE)) {
-      processed_events = true;
-      if (message.message == WM_QUIT) {
-        keep_running = false;
-        break;
-      }
-      ::TranslateMessage(&message);
-      ::DispatchMessage(&message);
-      // Allow Flutter to process messages each time a Windows message is
-      // processed, to prevent starvation.
-      next_flutter_event_time =
-          std::min(next_flutter_event_time, ProcessFlutterMessages());
-    }
-    // If the PeekMessage loop didn't run, process Flutter messages.
-    if (!processed_events) {
-      next_flutter_event_time =
-          std::min(next_flutter_event_time, ProcessFlutterMessages());
-    }
-  }
-}
-
-void RunLoop::RegisterFlutterInstance(
-    flutter::FlutterEngine* flutter_instance) {
-  flutter_instances_.insert(flutter_instance);
-}
-
-void RunLoop::UnregisterFlutterInstance(
-    flutter::FlutterEngine* flutter_instance) {
-  flutter_instances_.erase(flutter_instance);
-}
-
-RunLoop::TimePoint RunLoop::ProcessFlutterMessages() {
-  TimePoint next_event_time = TimePoint::max();
-  for (auto instance : flutter_instances_) {
-    std::chrono::nanoseconds wait_duration = instance->ProcessMessages();
-    if (wait_duration != std::chrono::nanoseconds::max()) {
-      next_event_time =
-          std::min(next_event_time, TimePoint::clock::now() + wait_duration);
-    }
-  }
-  return next_event_time;
-}

windows/runner/run_loop.h

@@ -1,40 +0,0 @@
-#ifndef RUNNER_RUN_LOOP_H_
-#define RUNNER_RUN_LOOP_H_
-
-#include <flutter/flutter_engine.h>
-
-#include <chrono>
-#include <set>
-
-// A runloop that will service events for Flutter instances as well
-// as native messages.
-class RunLoop {
- public:
-  RunLoop();
-  ~RunLoop();
-
-  // Prevent copying
-  RunLoop(RunLoop const&) = delete;
-  RunLoop& operator=(RunLoop const&) = delete;
-
-  // Runs the run loop until the application quits.
-  void Run();
-
-  // Registers the given Flutter instance for event servicing.
-  void RegisterFlutterInstance(
-      flutter::FlutterEngine* flutter_instance);
-
-  // Unregisters the given Flutter instance from event servicing.
-  void UnregisterFlutterInstance(
-      flutter::FlutterEngine* flutter_instance);
-
- private:
-  using TimePoint = std::chrono::steady_clock::time_point;
-
-  // Processes all currently pending messages for registered Flutter instances.
-  TimePoint ProcessFlutterMessages();
-
-  std::set<flutter::FlutterEngine*> flutter_instances_;
-};
-
-#endif  // RUNNER_RUN_LOOP_H_

windows/runner/runner.exe.manifest

@@ -7,7 +7,7 @@
   </application>
   <compatibility xmlns="urn:schemas-microsoft-com:compatibility.v1">
     <application>
-      <!-- Windows 10 -->
+      <!-- Windows 10 and Windows 11 -->
       <supportedOS Id="{8e0f7a12-bfb3-4fe8-b9a5-48fd50a15a9a}"/>
       <!-- Windows 8.1 -->
       <supportedOS Id="{1f676c76-80e1-4239-95bb-83d0f6d0da78}"/>

windows/runner/utils.cpp

@@ -47,16 +47,17 @@ std::string Utf8FromUtf16(const wchar_t* utf16_string) {
   }
   int target_length = ::WideCharToMultiByte(
       CP_UTF8, WC_ERR_INVALID_CHARS, utf16_string,
-      -1, nullptr, 0, nullptr, nullptr);
-  if (target_length == 0) {
-    return std::string();
-  }
+      -1, nullptr, 0, nullptr, nullptr)
+    -1; // remove the trailing null character
+  int input_length = (int)wcslen(utf16_string);
   std::string utf8_string;
+  if (target_length <= 0 || target_length > utf8_string.max_size()) {
+    return utf8_string;
+  }
   utf8_string.resize(target_length);
   int converted_length = ::WideCharToMultiByte(
       CP_UTF8, WC_ERR_INVALID_CHARS, utf16_string,
-      -1, utf8_string.data(),
-      target_length, nullptr, nullptr);
+      input_length, utf8_string.data(), target_length, nullptr, nullptr);
   if (converted_length == 0) {
     return std::string();
   }

windows/runner/win32_window.cpp

@@ -1,13 +1,31 @@
 #include "win32_window.h"
 
+#include <dwmapi.h>
 #include <flutter_windows.h>
 
 #include "resource.h"
 
 namespace {
 
+/// Window attribute that enables dark mode window decorations.
+///
+/// Redefined in case the developer's machine has a Windows SDK older than
+/// version 10.0.22000.0.
+/// See: https://docs.microsoft.com/windows/win32/api/dwmapi/ne-dwmapi-dwmwindowattribute
+#ifndef DWMWA_USE_IMMERSIVE_DARK_MODE
+#define DWMWA_USE_IMMERSIVE_DARK_MODE 20
+#endif
+
 constexpr const wchar_t kWindowClassName[] = L"FLUTTER_RUNNER_WIN32_WINDOW";
 
+/// Registry key for app theme preference.
+///
+/// A value of 0 indicates apps should use dark mode. A non-zero or missing
+/// value indicates apps should use light mode.
+constexpr const wchar_t kGetPreferredBrightnessRegKey[] =
+  L"Software\\Microsoft\\Windows\\CurrentVersion\\Themes\\Personalize";
+constexpr const wchar_t kGetPreferredBrightnessRegValue[] = L"AppsUseLightTheme";
+
 // The number of Win32Window objects that currently exist.
 static int g_active_window_count = 0;
 
@@ -31,8 +49,8 @@ void EnableFullDpiSupportIfAvailable(HWND hwnd) {
           GetProcAddress(user32_module, "EnableNonClientDpiScaling"));
   if (enable_non_client_dpi_scaling != nullptr) {
     enable_non_client_dpi_scaling(hwnd);
-    FreeLibrary(user32_module);
   }
+  FreeLibrary(user32_module);
 }
 
 }  // namespace
@@ -42,7 +60,7 @@ class WindowClassRegistrar {
  public:
   ~WindowClassRegistrar() = default;
 
-  // Returns the singleton registar instance.
+  // Returns the singleton registrar instance.
   static WindowClassRegistrar* GetInstance() {
     if (!instance_) {
       instance_ = new WindowClassRegistrar();
@@ -102,9 +120,9 @@ Win32Window::~Win32Window() {
   Destroy();
 }
 
-bool Win32Window::CreateAndShow(const std::wstring& title,
-                                const Point& origin,
-                                const Size& size) {
+bool Win32Window::Create(const std::wstring& title,
+                         const Point& origin,
+                         const Size& size) {
   Destroy();
 
   const wchar_t* window_class =
@@ -117,7 +135,7 @@ bool Win32Window::CreateAndShow(const std::wstring& title,
   double scale_factor = dpi / 96.0;
 
   HWND window = CreateWindow(
-      window_class, title.c_str(), WS_OVERLAPPEDWINDOW | WS_VISIBLE,
+      window_class, title.c_str(), WS_OVERLAPPEDWINDOW,
       Scale(origin.x, scale_factor), Scale(origin.y, scale_factor),
       Scale(size.width, scale_factor), Scale(size.height, scale_factor),
       nullptr, nullptr, GetModuleHandle(nullptr), this);
@@ -126,9 +144,15 @@ bool Win32Window::CreateAndShow(const std::wstring& title,
     return false;
   }
 
+  UpdateTheme(window);
+
   return OnCreate();
 }
 
+bool Win32Window::Show() {
+  return ShowWindow(window_handle_, SW_SHOWNORMAL);
+}
+
 // static
 LRESULT CALLBACK Win32Window::WndProc(HWND const window,
                                       UINT const message,
@@ -188,6 +212,10 @@ Win32Window::MessageHandler(HWND hwnd,
         SetFocus(child_content_);
       }
       return 0;
+
+    case WM_DWMCOLORIZATIONCOLORCHANGED:
+      UpdateTheme(hwnd);
+      return 0;
   }
 
   return DefWindowProc(window_handle_, message, wparam, lparam);
@@ -243,3 +271,18 @@ bool Win32Window::OnCreate() {
 void Win32Window::OnDestroy() {
   // No-op; provided for subclasses.
 }
+
+void Win32Window::UpdateTheme(HWND const window) {
+  DWORD light_mode;
+  DWORD light_mode_size = sizeof(light_mode);
+  LSTATUS result = RegGetValue(HKEY_CURRENT_USER, kGetPreferredBrightnessRegKey,
+                               kGetPreferredBrightnessRegValue,
+                               RRF_RT_REG_DWORD, nullptr, &light_mode,
+                               &light_mode_size);
+
+  if (result == ERROR_SUCCESS) {
+    BOOL enable_dark_mode = light_mode == 0;
+    DwmSetWindowAttribute(window, DWMWA_USE_IMMERSIVE_DARK_MODE,
+                          &enable_dark_mode, sizeof(enable_dark_mode));
+  }
+}

windows/runner/win32_window.h

@@ -28,15 +28,16 @@ class Win32Window {
   Win32Window();
   virtual ~Win32Window();
 
-  // Creates and shows a win32 window with |title| and position and size using
+  // Creates a win32 window with |title| that is positioned and sized using
   // |origin| and |size|. New windows are created on the default monitor. Window
   // sizes are specified to the OS in physical pixels, hence to ensure a
-  // consistent size to will treat the width height passed in to this function
-  // as logical pixels and scale to appropriate for the default monitor. Returns
-  // true if the window was created successfully.
-  bool CreateAndShow(const std::wstring& title,
-                     const Point& origin,
-                     const Size& size);
+  // consistent size this function will scale the inputted width and height as
+  // as appropriate for the default monitor. The window is invisible until
+  // |Show| is called. Returns true if the window was created successfully.
+  bool Create(const std::wstring& title, const Point& origin, const Size& size);
+
+  // Show the current window. Returns true if the window was successfully shown.
+  bool Show();
 
   // Release OS resources associated with window.
   void Destroy();
@@ -76,7 +77,7 @@ class Win32Window {
   // OS callback called by message pump. Handles the WM_NCCREATE message which
   // is passed when the non-client area is being created and enables automatic
   // non-client DPI scaling so that the non-client area automatically
-  // responsponds to changes in DPI. All other messages are handled by
+  // responds to changes in DPI. All other messages are handled by
   // MessageHandler.
   static LRESULT CALLBACK WndProc(HWND const window,
                                   UINT const message,
@@ -86,6 +87,9 @@ class Win32Window {
   // Retrieves a class instance pointer for |window|
   static Win32Window* GetThisFromHandle(HWND const window) noexcept;
 
+  // Update the window frame's theme to match the system theme.
+  static void UpdateTheme(HWND const window);
+
   bool quit_on_close_ = false;
 
   // window handle for top level window.