[win] Add support for dark mode on Windows 11

Fixes aseprite/aseprite#3527
aseprite · Aug 16, 2023 · 7847847 · 7847847
1 parent c182b50
commit 7847847
Show file tree

Hide file tree

Showing 4 changed files with 55 additions and 3 deletions.
diff --git a/base/win/registry.cpp b/base/win/registry.cpp
@@ -1,4 +1,5 @@
 // LAF Base Library
+// Copyright (c) 2023 Igara Studio S.A.
 // Copyright (c) 2017 David Capello
 //
 // This file is released under the terms of the MIT license.
@@ -101,6 +102,14 @@ void hkey::close()
   }
 }
 
+bool hkey::exists(const std::string& name)
+{
+  std::wstring wname = from_utf8(name);
+  LONG result = RegQueryValueExW(m_hkey, wname.c_str(),
+                                 nullptr, nullptr, nullptr, nullptr);
+  return (result == ERROR_SUCCESS);
+}
+
 std::string hkey::string(const std::string& name)
 {
   if (!m_hkey)

diff --git a/base/win/registry.h b/base/win/registry.h
@@ -1,5 +1,5 @@
 // LAF Base Library
-// Copyright (c) 2021 Igara Studio S.A.
+// Copyright (c) 2021-2023 Igara Studio S.A.
 // Copyright (c) 2017 David Capello
 //
 // This file is released under the terms of the MIT license.
@@ -44,6 +44,8 @@ class hkey {
   hkey create(const std::string& subkey);
   void close();
 
+  bool exists(const std::string& name);
+
   std::string string(const std::string& name);
   void string(const std::string& name, const std::string& value);
 

diff --git a/os/win/window.cpp b/os/win/window.cpp
@@ -1,5 +1,5 @@
 // LAF OS Library
-// Copyright (C) 2018-2022  Igara Studio S.A.
+// Copyright (C) 2018-2023  Igara Studio S.A.
 // Copyright (C) 2012-2018  David Capello
 //
 // This file is released under the terms of the MIT license.
@@ -28,6 +28,8 @@
 #include "base/string.h"
 #include "base/thread.h"
 #include "base/win/comptr.h"
+#include "base/win/registry.h"
+#include "base/win/win32_exception.h"
 #include "gfx/border.h"
 #include "gfx/region.h"
 #include "gfx/size.h"
@@ -131,6 +133,10 @@ static BOOL CALLBACK log_monitor_info(HMONITOR monitor,
   return TRUE;
 }
 
+// Keys used to detect if the Windows 11 dark mode is selected.
+static constexpr const char* kPersonalizeKey = "Software\\Microsoft\\Windows\\CurrentVersion\\Themes\\Personalize";
+static constexpr const char* kAppsUseLightThemeValue = "AppsUseLightTheme";
+
 PointerType WindowWin::m_pointerType = PointerType::Unknown;
 float WindowWin::m_pressure = 0.0f;
 std::vector<PACKET> WindowWin::m_packets;
@@ -874,6 +880,7 @@ LRESULT WindowWin::wndProc(UINT msg, WPARAM wparam, LPARAM lparam)
         }
       }
 
+      checkDarkModeChange();
       notifyFullScreenStateToShell();
       break;
     }
@@ -1133,6 +1140,10 @@ LRESULT WindowWin::wndProc(UINT msg, WPARAM wparam, LPARAM lparam)
       onEndResizing();
       break;
 
+    case WM_SETTINGCHANGE:
+      checkDarkModeChange();
+      break;
+
     // Mouse and Trackpad Messages
 
     case WM_MOUSEMOVE: {
@@ -2343,6 +2354,35 @@ void WindowWin::checkColorSpaceChange()
     onChangeColorSpace();
 }
 
+// We only support the Windows 11 dark mode, detecting it and using
+// the correct (dark/light) title bar.
+//
+// A lot of information and discussion about this can be found here:
+// https://github.com/microsoft/WindowsAppSDK/issues/41
+void WindowWin::checkDarkModeChange()
+{
+  try {
+    auto key = base::hkey::current_user().open(kPersonalizeKey,
+                                               base::hkey::read);
+
+    // We can check if "AppsUseLightTheme" option is 0 which means
+    // that we have to use the dark theme. Not sure why this is not
+    // automatic or the default behavior on Windows 11, or configured
+    // through the manifest for Win32 apps.
+    if (key.exists(kAppsUseLightThemeValue)) {
+      BOOL value = (key.dword(kAppsUseLightThemeValue) == 0);
+      DwmSetWindowAttribute(
+        m_hwnd, 20, // DWMWA_USE_IMMERSIVE_DARK_MODE,
+        &value, sizeof(BOOL));
+    }
+  }
+  catch (const base::Win32Exception&) {
+    // Probably the "Personalize" key doesn't exist because we are on
+    // Windows 10, so we do nothing, which means: use the light
+    // theme/current theme/title bar as it is.
+  }
+}
+
 void WindowWin::openWintabCtx()
 {
   const TabletAPI tabletAPI = system()->tabletAPI();

diff --git a/os/win/window.h b/os/win/window.h
@@ -1,5 +1,5 @@
 // LAF OS Library
-// Copyright (C) 2018-2021  Igara Studio S.A.
+// Copyright (C) 2018-2023  Igara Studio S.A.
 // Copyright (C) 2012-2018  David Capello
 //
 // This file is released under the terms of the MIT license.
@@ -91,6 +91,7 @@ namespace os {
     void clearDelayedTouchEvents();
     void killTouchTimer();
     void checkColorSpaceChange();
+    void checkDarkModeChange();
 
     void openWintabCtx();
     void closeWintabCtx();