might be functional

include/Mw/LowLevel.h

@@ -163,6 +163,7 @@ struct _MwLLHandler {
 	void (*focus_in)(MwLL handle, void* data);
 	void (*focus_out)(MwLL handle, void* data);
 	void (*clipboard)(MwLL handle, void* data);
+	void (*dark_theme)(MwLL handle, void* data);
 };
 
 #ifdef __cplusplus

include/Mw/LowLevel/GDI.h

@@ -22,6 +22,7 @@ struct _MwLLGDI {
 	int grabbed;
 	int force_render;
 	int get_clipboard;
+	int get_darktheme;
 };
 
 struct _MwLLGDIColor {

src/backend/gdi.c

@@ -8,6 +8,17 @@ typedef struct userdata {
 	int   max_set;
 } userdata_t;
 
+static void detect_darktheme(MwLL handle){
+	DWORD dw;
+	DWORD sz = sizeof(dw);
+
+	if(RegGetValue(HKEY_CURRENT_USER, "Software\\Microsoft\\Windows\\CurrentVersion\\Themes\\Personalize", "AppsUseLightTheme", RRF_RT_REG_DWORD, NULL, &dw, &sz) == ERROR_SUCCESS){
+		int t = dw ? 0 : 1;
+
+		MwLLDispatch(handle, dark_theme, &t);
+	}
+}
+
 static LRESULT CALLBACK wndproc(HWND hWnd, UINT msg, WPARAM wp, LPARAM lp) {
 	userdata_t* u = (userdata_t*)GetWindowLongPtr(hWnd, GWLP_USERDATA);
 
@@ -205,6 +216,10 @@ static LRESULT CALLBACK wndproc(HWND hWnd, UINT msg, WPARAM wp, LPARAM lp) {
 	} else if(msg == WM_USER) {
 		InvalidateRect(hWnd, NULL, FALSE);
 		UpdateWindow(hWnd);
+	} else if(msg == WM_WININICHANGE){
+		char* s = (char*)lp;
+		
+		if(s != NULL && strcmp(s, "ImmersiveColorSet") == 0) detect_darktheme(u->ll);
 	} else {
 		return DefWindowProc(hWnd, msg, wp, lp);
 	}
@@ -238,6 +253,7 @@ static MwLL MwLLCreateImpl(MwLL parent, int x, int y, int width, int height) {
 	r->common.type	      = MwLLBackendGDI;
 
 	r->gdi.get_clipboard = 1;
+	r->gdi.get_darktheme = 1;
 	r->gdi.force_render  = 0;
 	r->gdi.grabbed	     = 0;
 	r->gdi.hWnd	     = CreateWindow("milsko", "Milsko", parent == NULL ? (WS_OVERLAPPEDWINDOW) : (WS_CHILD | WS_VISIBLE), x == MwDEFAULT ? CW_USEDEFAULT : x, y == MwDEFAULT ? CW_USEDEFAULT : y, width, height, parent == NULL ? NULL : parent->gdi.hWnd, 0, wc.hInstance, NULL);
@@ -384,7 +400,7 @@ static int MwLLPendingImpl(MwLL handle) {
 
 	(void)handle;
 
-	if(handle->gdi.get_clipboard) return 1;
+	if(handle->gdi.get_clipboard || handle->gdi.get_darktheme) return 1;
 	return PeekMessage(&msg, handle->gdi.hWnd, 0, 0, PM_NOREMOVE) ? 1 : 0;
 }
 
@@ -411,6 +427,11 @@ static void MwLLNextEventImpl(MwLL handle) {
 
 		handle->gdi.get_clipboard = 0;
 	}
+	if(handle->gdi.get_darktheme){
+		detect_darktheme(handle);
+
+		handle->gdi.get_clipboard = 0;
+	}
 	while(PeekMessage(&msg, handle->gdi.hWnd, 0, 0, PM_NOREMOVE)) {
 		GetMessage(&msg, handle->gdi.hWnd, 0, 0);
 		TranslateMessage(&msg);

src/core.c

@@ -127,6 +127,13 @@ static void llclipboardhandler(MwLL handle, void* data) {
  */
 #define IsFirstVisible(handle) ((handle)->widget_class != NULL && ((handle)->parent == NULL || (handle)->parent->widget_class == NULL))
 
+static void lldarkthemehandler(MwLL handle, void* data){
+	MwWidget h = (MwWidget)handle->common.user;
+	int* ptr = data;
+
+	if(IsFirstVisible(h)) MwToggleDarkTheme(h, *ptr);
+}
+
 MwWidget MwCreateWidget(MwClass widget_class, const char* name, MwWidget parent, int x, int y, unsigned int width, unsigned int height) {
 	MwWidget h = malloc(sizeof(*h));
 
@@ -171,6 +178,7 @@ MwWidget MwCreateWidget(MwClass widget_class, const char* name, MwWidget parent,
 		h->lowlevel->common.handler->focus_in	  = llfocusinhandler;
 		h->lowlevel->common.handler->focus_out	  = llfocusouthandler;
 		h->lowlevel->common.handler->clipboard	  = llclipboardhandler;
+		h->lowlevel->common.handler->dark_theme	  = lldarkthemehandler;
 	}
 
 	if(parent != NULL) arrput(parent->children, h);