player: always notify when writing window-scale option

As described in the previous commit, update_window_scale will always
execute whenever window-scale is written even if the value doesn't
change.

DOCS/man/input.rst

@@ -2690,30 +2690,6 @@ Property list
     enabled, or after precise seeking). Files with imprecise timestamps (such
     as Matroska) might lead to unstable results.
 
-``window-scale`` (RW)
-    Window size multiplier. Setting this will resize the video window to the
-    values contained in ``dwidth`` and ``dheight`` multiplied with the value
-    set with this property. Setting ``1`` will resize to original video size
-    (or to be exact, the size the video filters output). ``2`` will set the
-    double size, ``0.5`` halves the size.
-
-    Note that setting a value identical to its previous value will not resize
-    the window. That's because this property mirrors the ``window-scale``
-    option, and setting an option to its previous value is ignored. If this
-    value is set while the window is in a fullscreen, the multiplier is not
-    applied until the window is taken out of that state. Writing this property
-    to a maximized window can unmaximize the window depending on the OS and
-    window manager. If the window does not unmaximize, the multiplier will be
-    applied if the user unmaximizes the window later.
-
-    See ``current-window-scale`` for the value derived from the actual window
-    size.
-
-    Since mpv 0.31.0, this always returns the previously set value (or the
-    default value), instead of the value implied by the actual window size.
-    Before mpv 0.31.0, this returned what ``current-window-scale`` returns now,
-    after the window was created.
-
 ``current-window-scale`` (RW)
     The ``window-scale`` value calculated from the current window size. This
     has the same value as ``window-scale`` if the window size was not changed
@@ -2722,10 +2698,9 @@ Property list
     calculated from the last non-fullscreen size of the window. The property
     is unavailable if no video is active.
 
-    When setting this property in the fullscreen or maximized state, the behavior
-    is the same as window-scale. In all other cases, setting the value of this
-    property will always resize the window. This does not affect the value of
-    ``window-scale``.
+    It is also possible to write to this property. This has the same behavior as
+    writing ``window-scale``. Note that writing to ``current-window-scale`` will
+    not affect the value of ``window-scale``.
 
 ``focused``
     Whether the window has focus. Might not be supported by all VOs.

DOCS/man/options.rst

@@ -3397,7 +3397,10 @@ Window
 ``--window-scale=<factor>``
     Resize the video window to a multiple (or fraction) of the video size. This
     option is applied before ``--autofit`` and other options are applied (so
-    they override this option).
+    they override this option). Changing this option while the window is
+    maximized can unmaximize the window depending on the OS and window manager.
+    If the window does not unmaximize, the multiplier will be applied if the user
+    unmaximizes the window later.
 
     For example, ``--window-scale=0.5`` would show the window at half the
     video size.

etc/input.conf

@@ -117,9 +117,9 @@
 #6 add gamma 1
 #7 add saturation -1
 #8 add saturation 1
-#Alt+0 set current-window-scale 0.5     # halve the window size
-#Alt+1 set current-window-scale 1.0     # reset the window size
-#Alt+2 set current-window-scale 2.0     # double the window size
+#Alt+0 set window-scale 0.5             # halve the window size
+#Alt+1 set window-scale 1.0             # reset the window size
+#Alt+2 set window-scale 2.0             # double the window size
 #b cycle deband                         # toggle the debanding filter
 #d cycle deinterlace                    # cycle the deinterlacing filter
 #r add sub-pos -1                       # move subtitles up

options/options.c

@@ -128,7 +128,7 @@ static const m_option_t mp_vo_opt_list[] = {
     {"autofit-larger", OPT_SIZE_BOX(autofit_larger)},
     {"autofit-smaller", OPT_SIZE_BOX(autofit_smaller)},
     {"auto-window-resize", OPT_BOOL(auto_window_resize)},
-    {"window-scale", OPT_DOUBLE(window_scale), M_RANGE(0.001, 100)},
+    {"window-scale", OPT_DOUBLE(window_scale), M_RANGE(0.001, 100), .force_update = true},
     {"window-minimized", OPT_BOOL(window_minimized)},
     {"window-maximized", OPT_BOOL(window_maximized)},
     {"focus-on-open", OPT_REMOVED("Replaced by --focus-on")},