Enhanced dark mode. (#984)

* Dark mode for title bar and menus.

src/winmain.c

@@ -183,7 +183,6 @@ trace_winsize(char * tag)
 #define trace_winsize(tag)	
 #endif
 
-
 static HRESULT (WINAPI * pDwmIsCompositionEnabled)(BOOL *) = 0;
 static HRESULT (WINAPI * pDwmExtendFrameIntoClientArea)(HWND, const MARGINS *) = 0;
 static HRESULT (WINAPI * pDwmEnableBlurBehindWindow)(HWND, void *) = 0;
@@ -193,7 +192,8 @@ static HRESULT (WINAPI * pSetWindowCompositionAttribute)(HWND, void *) = 0;
 static BOOL (WINAPI * pSystemParametersInfo)(UINT, UINT, PVOID, UINT) = 0;
 
 static BOOLEAN (WINAPI * pShouldAppsUseDarkMode)(void) = 0; /* undocumented */
-static BOOLEAN (WINAPI * pShouldSystUseDarkMode)(void) = 0; /* undocumented */
+static BOOLEAN (WINAPI * pAllowDarkModeForApp)(BOOLEAN) = 0; /* undocumented */
+static DWORD (WINAPI * pSetPreferredAppMode)(DWORD) = 0; /* undocumented */
 static HRESULT (WINAPI * pSetWindowTheme)(HWND, const wchar_t *, const wchar_t *) = 0;
 
 #define HTHEME HANDLE
@@ -243,8 +243,13 @@ load_dwm_funcs(void)
   if (uxtheme) {
     pShouldAppsUseDarkMode = 
       (void *)GetProcAddress(uxtheme, MAKEINTRESOURCEA(132)); /* ordinal */
-    pShouldSystUseDarkMode = 
-      (void *)GetProcAddress(uxtheme, MAKEINTRESOURCEA(138)); /* ordinal */
+    if (HIWORD(GetVersion()) < 18362) { /* 1903 */
+      pAllowDarkModeForApp = 
+        (void *)GetProcAddress(uxtheme, MAKEINTRESOURCEA(135)); /* ordinal */
+    } else {
+      pSetPreferredAppMode = 
+        (void *)GetProcAddress(uxtheme, MAKEINTRESOURCEA(135)); /* ordinal */
+    }
     pSetWindowTheme = 
       (void *)GetProcAddress(uxtheme, "SetWindowTheme");
     pOpenThemeData =
@@ -4875,6 +4880,15 @@ main(int argc, char *argv[])
     }
   }
 
+  // Set app mode
+  if (pAllowDarkModeForApp || pSetPreferredAppMode) {
+    if (HIWORD(GetVersion()) < 18362) {
+      pAllowDarkModeForApp(1);
+    } else {
+      pSetPreferredAppMode(1); /* AllowDark */
+    }
+  }
+
   // The window class.
   class_atom = RegisterClassExW(&(WNDCLASSEXW){
     .cbSize = sizeof(WNDCLASSEXW),
@@ -4937,19 +4951,20 @@ main(int argc, char *argv[])
   trace_winsize("createwindow");
 
   // Dark mode support
-  if (pShouldSystUseDarkMode) {
+  if (pShouldAppsUseDarkMode) {
     HIGHCONTRASTW hc;
     hc.cbSize = sizeof hc;
     pSystemParametersInfo(SPI_GETHIGHCONTRAST, sizeof hc, &hc, 0);
     //printf("High Contrast scheme <%ls>\n", hc.lpszDefaultScheme);
 
-    if (!(hc.dwFlags & HCF_HIGHCONTRASTON) && pShouldSystUseDarkMode()) {
+    if (!(hc.dwFlags & HCF_HIGHCONTRASTON) && pShouldAppsUseDarkMode()) {
       pSetWindowTheme(wnd, W("DarkMode_Explorer"), NULL);
       BOOL dark = 1;
 
       // set DWMWA_USE_IMMERSIVE_DARK_MODE
-      pDwmSetWindowAttribute(wnd, 20, &dark, sizeof dark);
-      pDwmSetWindowAttribute(wnd, 19, &dark, sizeof dark);
+      if (pDwmSetWindowAttribute(wnd, 20, &dark, sizeof dark)) {
+        pDwmSetWindowAttribute(wnd, 19, &dark, sizeof dark);
+      }
     }
   }