From 4907859ee039f0d707b21050c2dec7d49f571590 Mon Sep 17 00:00:00 2001
From: Stefan Kangas <stefankangas@gmail.com>
Date: Thu, 15 Sep 2022 19:12:10 +0200
Subject: [PATCH] Document MS-Windows support in wallpaper.el

* lisp/image/wallpaper.el: Add MS-Windows to Commentary.
(wallpaper-command, wallpaper-command-args, wallpaper-set):
Document MS-Windows support.
---
 etc/NEWS                |  4 ++--
 lisp/image/wallpaper.el | 30 ++++++++++++++++--------------
 2 files changed, 18 insertions(+), 16 deletions(-)

diff --git a/etc/NEWS b/etc/NEWS
index cc68cd82b86..72c330f5f77 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -2467,8 +2467,8 @@ This package provides the command 'wallpaper-set', which sets the
 desktop background image.  Depending on the system and the desktop,
 this may require an external program (such as 'swaybg', 'gm',
 'display' or 'xloadimage').  If so, a suitable command should be
-detected automatically in most cases, and can also be customized
-manually if needed using the new user options 'wallpaper-command' and
+detected automatically in most cases.  It can also be customized
+manually if needed, using the new user options 'wallpaper-command' and
 'wallpaper-command-args'.
 
 +++
diff --git a/lisp/image/wallpaper.el b/lisp/image/wallpaper.el
index fe6882a5880..5622f9b8e8a 100644
--- a/lisp/image/wallpaper.el
+++ b/lisp/image/wallpaper.el
@@ -28,19 +28,21 @@
 ;; On GNU/Linux and other Unix-like systems, it uses an external
 ;; command to set the desktop background.
 ;;
-;; On Haiku, it uses the `haiku-set-wallpaper' function, which does
-;; not rely on any external commands.
-;;
-;; On macOS, the "osascript" command is used.  You might need to
-;; disable the option "Change picture" in the "Desktop & Screensaver"
-;; preferences for this to work (this was seen with macOS 10.13).
-;;
 ;; Finding an external command to use is obviously a bit tricky to get
 ;; right, as there is no lack of platforms, window managers, desktop
 ;; environments and tools.  However, it should be detected
 ;; automatically in most cases.  If it doesn't work in your
 ;; environment, customize the user options `wallpaper-command' and
 ;; `wallpaper-command-args'.
+;;
+;; On MS-Windows, it uses the `w32-set-wallpaper' function, and on
+;; Haiku the `haiku-set-wallpaper' function, neither of which relies
+;; on any external commands.  The value of `wallpaper-command' and
+;; `wallpaper-command-args' are ignored on such systems.
+;;
+;; On macOS, the "osascript" command is used.  You might need to
+;; disable the option "Change picture" in the "Desktop & Screensaver"
+;; preferences for this to work (this was seen with macOS 10.13).
 
 ;;; Code:
 
@@ -131,7 +133,7 @@ Used to set `wallpaper-command'."
                  (wallpaper--find-command-arguments))))
 
 (defcustom wallpaper-command (wallpaper--find-command)
-  "Executable used for setting the wallpaper.
+  "Executable used by `wallpaper-set' for setting the wallpaper.
 A suitable command for your environment should be detected
 automatically, so there is usually no need to customize this.
 
@@ -147,8 +149,8 @@ hear about it!  Please send an email to bug-gnu-emacs@gnu.org and
 tell us the command (and all options) that worked for you.  You
 can also use \\[report-emacs-bug].
 
-The value of this variable is ignored on Haiku systems, where a
-native API will be used instead (see `haiku-set-wallpaper')."
+The value of this variable is ignored on MS-Windows and Haiku
+systems, where a native API is used instead."
   :type
   '(choice
     (radio
@@ -186,8 +188,8 @@ returned by `display-pixel-width').
 If `wallpaper-set' is run from a TTY frame, it will prompt for a
 height and width for \"%h\" and \"%w\" instead.
 
-The value of this variable is ignored on Haiku systems, where a
-native API will be used instead (see `haiku-set-wallpaper')."
+The value of this variable is ignored on MS-Windows and Haiku
+systems, where a native API is used instead."
   :type '(repeat string)
   :group 'image
   :version "29.1")
@@ -233,8 +235,8 @@ external command.  Which command to use is automatically detected
 in most cases, but can be manually customized with the user
 options `wallpaper-command' and `wallpaper-command-args'.
 
-On Haiku, no external command is needed, so the value of
-`wallpaper-commands' is ignored."
+On MS-Windows and Haiku systems, no external command is needed,
+so the value of `wallpaper-commands' is ignored."
   (interactive (list (and
                       (display-graphic-p)
                       (read-file-name "Set desktop background to: "
-- 
2.39.2