From f3874210b26f5d8b969491d4c2d4266beebb45bb Mon Sep 17 00:00:00 2001
From: Toni Wilen <twilen@winuae.net>
Date: Sun, 12 May 2024 20:00:12 +0300
Subject: [PATCH] Darkmode follow Windows/external program setting

---
 od-win32/darkmode.cpp | 46 ++++++++++++++++++++++++++++++++-----------
 od-win32/darkmode.h   |  5 +++--
 od-win32/win32.cpp    | 14 +++++++++++--
 3 files changed, 50 insertions(+), 15 deletions(-)

diff --git a/od-win32/darkmode.cpp b/od-win32/darkmode.cpp
index 158ee604..97807f4c 100644
--- a/od-win32/darkmode.cpp
+++ b/od-win32/darkmode.cpp
@@ -24,6 +24,7 @@ extern void write_log(const char *, ...);
 bool g_darkModeSupported = false;
 bool g_darkModeEnabled = false;
 int darkModeForced = 0;
+int darkModeDetect = 0;
 DWORD g_buildNumber = 0;
 
 fnSetWindowCompositionAttribute _SetWindowCompositionAttribute = nullptr;
@@ -41,6 +42,14 @@ fnSetPreferredAppMode _SetPreferredAppMode = nullptr;
 
 COLORREF dark_text_color, dark_bg_color;
 
+int GetAppDarkModeState(void)
+{
+	if (!_ShouldAppsUseDarkMode) {
+		return -1;
+	}
+	return _ShouldAppsUseDarkMode() ? 1 : 0;
+}
+
 bool AllowDarkModeForWindow(HWND hWnd, bool allow)
 {
 	if (g_darkModeSupported)
@@ -191,25 +200,38 @@ void InitDarkMode(int enable)
 				{
 					g_darkModeSupported = true;
 
-					if (darkModeForced > 0) {
-						AllowDarkModeForApp(PreferredAppMode::ForceDark);
-					} else  if (darkModeForced < 0) {
-						AllowDarkModeForApp(PreferredAppMode::ForceLight);
-					} else if (enable == -1 || enable == 1) {
-						AllowDarkModeForApp(PreferredAppMode::AllowDark);
-					} else {
-						AllowDarkModeForApp(PreferredAppMode::Default);
+					if (!darkModeDetect) {
+						if (darkModeForced > 0) {
+							AllowDarkModeForApp(PreferredAppMode::ForceDark);
+						} else  if (darkModeForced < 0) {
+							AllowDarkModeForApp(PreferredAppMode::ForceLight);
+						} else if (enable == -1 || enable == 1) {
+							AllowDarkModeForApp(PreferredAppMode::AllowDark);
+						} else {
+							AllowDarkModeForApp(PreferredAppMode::Default);
+						}
+					} else if (darkModeDetect < 0) {
+						if (_ShouldAppsUseDarkMode()) {
+							AllowDarkModeForApp(PreferredAppMode::ForceDark);
+						} else {
+							AllowDarkModeForApp(PreferredAppMode::ForceLight);
+						}
 					}
+
 					_RefreshImmersiveColorPolicyState();
 
 					g_darkModeEnabled = _ShouldAppsUseDarkMode() && !IsHighContrast();
 					
 					if (g_darkModeEnabled && enable < -1) {
-						AllowDarkModeForApp(PreferredAppMode::ForceDark);
+						if (darkModeDetect < 0) {
+							AllowDarkModeForApp(PreferredAppMode::ForceDark);
+						}
 					}
 
 					if (!g_darkModeEnabled && enable > 0 && darkModeForced >= 0) {
-						AllowDarkModeForApp(PreferredAppMode::ForceDark);
+						if (darkModeDetect < 0) {
+							AllowDarkModeForApp(PreferredAppMode::ForceDark);
+						}
 						_RefreshImmersiveColorPolicyState();
 						g_darkModeEnabled = _ShouldAppsUseDarkMode() && !IsHighContrast();
 					}
@@ -224,7 +246,9 @@ void InitDarkMode(int enable)
 	}
 
 	if (!enable && g_darkModeSupported) {
-		AllowDarkModeForApp(PreferredAppMode::Default);
+		if (darkModeDetect < 0) {
+			AllowDarkModeForApp(PreferredAppMode::Default);
+		}
 		if (_RefreshImmersiveColorPolicyState != NULL) {
 			_RefreshImmersiveColorPolicyState();
 		}
diff --git a/od-win32/darkmode.h b/od-win32/darkmode.h
index 4ab5fd2f..2a8de6e6 100644
--- a/od-win32/darkmode.h
+++ b/od-win32/darkmode.h
@@ -73,7 +73,7 @@ using fnIsDarkModeAllowedForApp = bool (WINAPI *)(); // ordinal 139
 
 extern bool g_darkModeSupported;
 extern bool g_darkModeEnabled;
-extern int darkModeForced;
+extern int darkModeForced, darkModeDetect;
 extern COLORREF dark_text_color, dark_bg_color;;
 
 bool AllowDarkModeForWindow(HWND hWnd, bool allow);
@@ -84,4 +84,5 @@ void AllowDarkModeForApp(bool allow);
 void SubclassListViewControl(HWND hListView);
 void SubclassTreeViewControl(HWND hListView);
 void SubclassButtonControl(HWND hwnd);
-void SubClassStatusBar(HWND hwnd);
\ No newline at end of file
+void SubClassStatusBar(HWND hwnd);
+int GetAppDarkModeState(void);
diff --git a/od-win32/win32.cpp b/od-win32/win32.cpp
index b71f3d40..5ead2b9c 100644
--- a/od-win32/win32.cpp
+++ b/od-win32/win32.cpp
@@ -7187,6 +7187,8 @@ static int parseargs(const TCHAR *argx, const TCHAR *np, const TCHAR *np2)
 			darkModeForced = 1;
 		} else if (!_tcsicmp(np, _T("light"))) {
 			darkModeForced = -1;
+		} else if (!_tcsicmp(np, _T("default"))) {
+			darkModeDetect = -1;
 		}
 		return 2;
 	}
@@ -8320,16 +8322,24 @@ bool is_mainthread(void)
 void InitializeDarkMode(void)
 {
 	static int initialized = -10;
+	static int dmdetect = -10;
 
 	int v = -1;
 	regqueryint(NULL, _T("GUIDarkMode"), &v);
 	if (rp_isactive()) {
-		v = -2;
+		darkModeDetect = 1;
+	}
+	if (darkModeDetect) {
+		int dms = GetAppDarkModeState();
+		if (dms != dmdetect) {
+			dmdetect = dms;
+			initialized = -10;
+		}
+		v = -1;
 	}
 	if (darkModeForced) {
 		v = 1;
 	}
-
 	if (initialized != v) {
 		InitDarkMode(v);
 		write_log("dark mode supported: %d enabled: %d\n", g_darkModeSupported, g_darkModeEnabled);
-- 
2.47.3