diff --git a/doc/emacs/msdos.texi b/doc/emacs/msdos.texi
index 0f8f429b3f87..3c6c61613e27 100644
--- a/doc/emacs/msdos.texi
+++ b/doc/emacs/msdos.texi
@@ -1181,6 +1181,13 @@ The default is @code{t}, which fits well with the Windows default
click-to-focus policy.
@end ifnottex
+ On Windows 10 (version 1809 and higher) and Windows 11, Emacs title
+bars and scroll bars will follow the system Light or Dark mode,
+similar to other programs such as Explorer and Command Prompt. To
+change the color mode: Windows Settings > Personalization > Colors >
+Choose your color (or Choose your default app mode); then restart
+Emacs.
+
@ifnottex
@include msdos-xtra.texi
@end ifnottex
diff --git a/etc/NEWS b/etc/NEWS
index e475a49b98df..82d8048c235d 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -73,6 +73,14 @@ Image specifiers can now use ':type webp'.
*** 'display-buffer' now can set up the body size of the chosen window.
For example, an alist entry as '(window-width . (body-columns . 40))'
will make the body of the chosen window 40 columns wide.
+
+** MS-Windows
+
++++
+*** Supports dark mode on Windows 10 (version 1809 and higher) and Windows 11.
+Graphical frames now use the appropriate light or dark title bar and
+scroll bars, based on the user's Windows color settings.
+
* Editing Changes in Emacs 29.1
diff --git a/src/w32.c b/src/w32.c
index 9fe698d28d72..369e7ee4e1f0 100644
--- a/src/w32.c
+++ b/src/w32.c
@@ -2820,8 +2820,15 @@ sys_putenv (char *str)
#define REG_ROOT "SOFTWARE\\GNU\\Emacs"
+/* Query a value from the Windows Registry (under HKCU and HKLM),
+ where `key` is the registry key, `name` is the name, and `lpdwtype`
+ is a pointer to the return value's type. `lpwdtype` can be NULL if
+ you do not care about the type.
+
+ Returns: pointer to the value, or null pointer if the key/name does
+ not exist. */
LPBYTE
-w32_get_resource (const char *key, LPDWORD lpdwtype)
+w32_get_resource (const char *key, const char *name, LPDWORD lpdwtype)
{
LPBYTE lpvalue;
HKEY hrootkey = NULL;
@@ -2830,13 +2837,13 @@ w32_get_resource (const char *key, LPDWORD lpdwtype)
/* Check both the current user and the local machine to see if
we have any resources. */
- if (RegOpenKeyEx (HKEY_CURRENT_USER, REG_ROOT, 0, KEY_READ, &hrootkey) == ERROR_SUCCESS)
+ if (RegOpenKeyEx (HKEY_CURRENT_USER, key, 0, KEY_READ, &hrootkey) == ERROR_SUCCESS)
{
lpvalue = NULL;
- if (RegQueryValueEx (hrootkey, key, NULL, NULL, NULL, &cbData) == ERROR_SUCCESS
+ if (RegQueryValueEx (hrootkey, name, NULL, NULL, NULL, &cbData) == ERROR_SUCCESS
&& (lpvalue = xmalloc (cbData)) != NULL
- && RegQueryValueEx (hrootkey, key, NULL, lpdwtype, lpvalue, &cbData) == ERROR_SUCCESS)
+ && RegQueryValueEx (hrootkey, name, NULL, lpdwtype, lpvalue, &cbData) == ERROR_SUCCESS)
{
RegCloseKey (hrootkey);
return (lpvalue);
@@ -2847,13 +2854,13 @@ w32_get_resource (const char *key, LPDWORD lpdwtype)
RegCloseKey (hrootkey);
}
- if (RegOpenKeyEx (HKEY_LOCAL_MACHINE, REG_ROOT, 0, KEY_READ, &hrootkey) == ERROR_SUCCESS)
+ if (RegOpenKeyEx (HKEY_LOCAL_MACHINE, key, 0, KEY_READ, &hrootkey) == ERROR_SUCCESS)
{
lpvalue = NULL;
- if (RegQueryValueEx (hrootkey, key, NULL, NULL, NULL, &cbData) == ERROR_SUCCESS
+ if (RegQueryValueEx (hrootkey, name, NULL, NULL, NULL, &cbData) == ERROR_SUCCESS
&& (lpvalue = xmalloc (cbData)) != NULL
- && RegQueryValueEx (hrootkey, key, NULL, lpdwtype, lpvalue, &cbData) == ERROR_SUCCESS)
+ && RegQueryValueEx (hrootkey, name, NULL, lpdwtype, lpvalue, &cbData) == ERROR_SUCCESS)
{
RegCloseKey (hrootkey);
return (lpvalue);
@@ -3077,7 +3084,7 @@ init_environment (char ** argv)
int dont_free = 0;
char bufc[SET_ENV_BUF_SIZE];
- if ((lpval = w32_get_resource (env_vars[i].name, &dwType)) == NULL
+ if ((lpval = w32_get_resource (REG_ROOT, env_vars[i].name, &dwType)) == NULL
/* Also ignore empty environment variables. */
|| *lpval == 0)
{
diff --git a/src/w32.h b/src/w32.h
index ffa145b1484a..ec0f37123e83 100644
--- a/src/w32.h
+++ b/src/w32.h
@@ -161,8 +161,9 @@ extern void prepare_standard_handles (int in, int out,
extern void reset_standard_handles (int in, int out,
int err, HANDLE handles[4]);
-/* Return the string resource associated with KEY of type TYPE. */
-extern LPBYTE w32_get_resource (const char * key, LPDWORD type);
+/* Query Windows Registry and return the resource associated
+ associated with KEY and NAME of type TYPE. */
+extern LPBYTE w32_get_resource (const char * key, const char * name, LPDWORD type);
extern void release_listen_threads (void);
extern void init_ntproc (int);
diff --git a/src/w32fns.c b/src/w32fns.c
index 14d1154a2bc5..bcf0f50c6a6c 100644
--- a/src/w32fns.c
+++ b/src/w32fns.c
@@ -73,6 +73,18 @@ along with GNU Emacs. If not, see . */
#include
#include
+/*
+ Internal/undocumented constants for Windows Dark mode.
+ See: https://github.com/microsoft/WindowsAppSDK/issues/41
+*/
+#define DARK_MODE_APP_NAME L"DarkMode_Explorer"
+/* For Windows 10 version 1809, 1903, 1909. */
+#define DWMWA_USE_IMMERSIVE_DARK_MODE_OLD 19
+/* For Windows 10 version 2004 and higher, and Windows 11. */
+#ifndef DWMWA_USE_IMMERSIVE_DARK_MODE
+#define DWMWA_USE_IMMERSIVE_DARK_MODE 20
+#endif
+
#ifndef FOF_NO_CONNECTED_ELEMENTS
#define FOF_NO_CONNECTED_ELEMENTS 0x2000
#endif
@@ -185,6 +197,11 @@ typedef BOOL (WINAPI *IsDebuggerPresent_Proc) (void);
typedef HRESULT (WINAPI *SetThreadDescription_Proc)
(HANDLE hThread, PCWSTR lpThreadDescription);
+typedef HRESULT (WINAPI * SetWindowTheme_Proc)
+ (IN HWND hwnd, IN LPCWSTR pszSubAppName, IN LPCWSTR pszSubIdList);
+typedef HRESULT (WINAPI * DwmSetWindowAttribute_Proc)
+ (HWND hwnd, DWORD dwAttribute, IN LPCVOID pvAttribute, DWORD cbAttribute);
+
TrackMouseEvent_Proc track_mouse_event_fn = NULL;
ImmGetCompositionString_Proc get_composition_string_fn = NULL;
ImmGetContext_Proc get_ime_context_fn = NULL;
@@ -199,6 +216,8 @@ EnumDisplayMonitors_Proc enum_display_monitors_fn = NULL;
GetTitleBarInfo_Proc get_title_bar_info_fn = NULL;
IsDebuggerPresent_Proc is_debugger_present = NULL;
SetThreadDescription_Proc set_thread_description = NULL;
+SetWindowTheme_Proc SetWindowTheme_fn = NULL;
+DwmSetWindowAttribute_Proc DwmSetWindowAttribute_fn = NULL;
extern AppendMenuW_Proc unicode_append_menu;
@@ -252,6 +271,9 @@ int w32_major_version;
int w32_minor_version;
int w32_build_number;
+/* If the OS is set to use dark mode. */
+BOOL w32_darkmode = FALSE;
+
/* Distinguish between Windows NT and Windows 95. */
int os_subtype;
@@ -2279,10 +2301,36 @@ w32_init_class (HINSTANCE hinst)
}
}
+/* Applies the Windows system theme (light or dark) to a window handle. */
+static void
+w32_applytheme (HWND hwnd)
+{
+ if (w32_darkmode)
+ {
+ /* Set window theme to that of a built-in Windows app (Explorer)
+ because it has dark scroll bars and other UI elements. */
+ if (SetWindowTheme_fn)
+ {
+ SetWindowTheme_fn (hwnd, DARK_MODE_APP_NAME, NULL);
+ }
+ /* Set the titlebar to system dark mode. */
+ if (DwmSetWindowAttribute_fn)
+ {
+ /* Windows 10 version 2004 and up, Windows 11. */
+ DWORD attr = DWMWA_USE_IMMERSIVE_DARK_MODE;
+ /* Windows 10 older than 2004. */
+ if (w32_build_number < 19041)
+ attr = DWMWA_USE_IMMERSIVE_DARK_MODE_OLD;
+ DwmSetWindowAttribute_fn
+ (hwnd, attr, &w32_darkmode, sizeof(w32_darkmode));
+ }
+ }
+}
+
static HWND
w32_createvscrollbar (struct frame *f, struct scroll_bar * bar)
{
- return CreateWindow ("SCROLLBAR", "",
+ HWND hwnd = CreateWindow ("SCROLLBAR", "",
/* Clip siblings so we don't draw over child
frames. Apparently this is not always
sufficient so we also try to make bar windows
@@ -2291,12 +2339,15 @@ w32_createvscrollbar (struct frame *f, struct scroll_bar * bar)
/* Position and size of scroll bar. */
bar->left, bar->top, bar->width, bar->height,
FRAME_W32_WINDOW (f), NULL, hinst, NULL);
+ if (hwnd)
+ w32_applytheme (hwnd);
+ return hwnd;
}
static HWND
w32_createhscrollbar (struct frame *f, struct scroll_bar * bar)
{
- return CreateWindow ("SCROLLBAR", "",
+ HWND hwnd = CreateWindow ("SCROLLBAR", "",
/* Clip siblings so we don't draw over child
frames. Apparently this is not always
sufficient so we also try to make bar windows
@@ -2305,6 +2356,9 @@ w32_createhscrollbar (struct frame *f, struct scroll_bar * bar)
/* Position and size of scroll bar. */
bar->left, bar->top, bar->width, bar->height,
FRAME_W32_WINDOW (f), NULL, hinst, NULL);
+ if (hwnd)
+ w32_applytheme (hwnd);
+ return hwnd;
}
static void
@@ -2390,6 +2444,9 @@ w32_createwindow (struct frame *f, int *coords)
/* Enable drag-n-drop. */
DragAcceptFiles (hwnd, TRUE);
+ /* Enable system light/dark theme. */
+ w32_applytheme (hwnd);
+
/* Do this to discard the default setting specified by our parent. */
ShowWindow (hwnd, SW_HIDE);
@@ -11028,6 +11085,36 @@ globals_of_w32fns (void)
set_thread_description = (SetThreadDescription_Proc)
get_proc_addr (hm_kernel32, "SetThreadDescription");
+ /* Support OS dark mode on Windows 10 version 1809 and higher.
+ See `w32_applytheme` which uses appropriate APIs per version of Windows.
+ For future wretches who may need to understand Windows build numbers:
+ https://docs.microsoft.com/en-us/windows/release-health/release-information
+ */
+ if (w32_major_version >= 10 && w32_build_number >= 17763
+ && os_subtype == OS_SUBTYPE_NT)
+ {
+ /* Load dwmapi and uxtheme, which will be needed to set window themes. */
+ HMODULE dwmapi_lib = LoadLibrary("dwmapi.dll");
+ DwmSetWindowAttribute_fn = (DwmSetWindowAttribute_Proc)
+ get_proc_addr (dwmapi_lib, "DwmSetWindowAttribute");
+ HMODULE uxtheme_lib = LoadLibrary("uxtheme.dll");
+ SetWindowTheme_fn = (SetWindowTheme_Proc)
+ get_proc_addr (uxtheme_lib, "SetWindowTheme");
+
+ /* Check Windows Registry for system theme. DWORD set to 0 or 1.
+ TODO: "Nice to have" would be to create a lisp setting (which
+ defaults to this Windows Registry value), then read that lisp
+ value here instead. This would allow the user to forcibly
+ override the system theme (which is also user-configurable in
+ Windows settings; see MS-Windows section in Emacs manual). */
+ LPBYTE val = w32_get_resource
+ ("Software\\Microsoft\\Windows\\CurrentVersion\\Themes\\Personalize",
+ "AppsUseLightTheme",
+ NULL);
+ if (val && (DWORD)*val == 0)
+ w32_darkmode = TRUE;
+ }
+
except_code = 0;
except_addr = 0;
#ifndef CYGWIN